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Sample records for sound enamel mesial

  1. Influence of bleaching agents on surface roughness of sound or eroded dental enamel specimens.

    Science.gov (United States)

    Azrak, Birgül; Callaway, Angelika; Kurth, Petra; Willershausen, Brita

    2010-12-01

    The aim of the present in vitro study was to assess the effect of bleaching agents on eroded and sound enamel specimens. Enamel specimens prepared from human permanent anterior teeth were incubated with different bleaching agents containing active ingredients as 7.5 or 13.5% hydrogen peroxide or 35% carbamide peroxide, ranging in pH from 4.9 to 10.8. The effect of the tooth whitening agents on surface roughness was tested for sound enamel surfaces as well as for eroded enamel specimens. To provoke erosive damage, the enamel specimens were incubated for 10 hours with apple juice (pH = 3.4). Afterwards, pretreated and untreated dental slices were incubated with one of the bleaching agents for 10 hours. The surface roughness (R(a)) of all enamel specimens (N = 80) was measured using an optical profilometric device. A descriptive statistical analysis of the R(a) values was performed. The study demonstrated that exposure to an acidic bleaching agent (pH = 4.9) resulted in a higher surface roughness (p = 0.043) than treatment with a high peroxide concentration (pH = 6.15). If the enamel surface was previously exposed to erosive beverages, subsequent bleaching may enhance damage to the dental hard tissue. Bleaching agents with a high concentration of peroxide or an acidic pH can influence the surface roughness of sound or eroded enamel. © 2010, COPYRIGHT THE AUTHORS. JOURNAL COMPILATION © 2010, WILEY PERIODICALS, INC.

  2. Structural and thermal behaviour of carious and sound powders of human tooth enamel and dentine

    International Nuclear Information System (INIS)

    Tiznado-Orozco, Gaby E; Garcia-Garcia, R; Reyes-Gasga, J

    2009-01-01

    Powder from carious human tooth enamel and dentine were structurally, chemically and thermally analysed and compared against those from sound (healthy) teeth. Structural and chemical analyses were performed using x-ray diffraction, energy-dispersive x-ray spectroscopy and transmission electron microscopy. Thermal analysis was carried out by thermogravimetric analysis, Fourier transform infrared spectroscopy and x-ray diffraction. Results demonstrate partially dissolved crystals of hydroxyapatite (HAP) with substitutions of Na, Mg, Cl and C, and a greater weight loss in carious dentine as compared with carious enamel. A greater amount of thermal decomposition is observed in carious dentine as compared with sound dentine, with major variations in the a-axis of the HAP unit cell than in the c-axis. Variations in shape and intensity of the OH - , CO 3 2- and PO 4 3- FTIR bands were also found.

  3. Selective Acid Etching Improves the Bond Strength of Universal Adhesive to Sound and Demineralized Enamel of Primary Teeth.

    Science.gov (United States)

    Antoniazzi, Bruna Feltrin; Nicoloso, Gabriel Ferreira; Lenzi, Tathiane Larissa; Soares, Fabio Zovico Maxnuck; Rocha, Rachel de Oliveira

    To evaluate the influence of enamel condition and etching strategy on bond strength of a universal adhesive in primary teeth. Thirty-six primary molars were randomly assigned to six groups (n = 6) according to the enamel condition (sound [S] and demineralized [DEM]/cariogenic challenge by pH cycling prior to restorative procedures) and adhesive system (Scotchbond Universal Adhesive [SBU]) used in either etch-and-rinse (ER) or selfetching (SE) mode, with Clearfil SE Bond as the self-etching control. The adhesives were applied to flat enamel surfaces and composite cylinders (0.72 mm2) were built up. After 24-h storage in water, specimens were subjected to the microshear test. Bond strength (MPa) data were analyzed using two-way ANOVA and Tukey's post-hoc tests (α = 0.05). Significant differences were found considering the factors adhesive system (p = 0.003) and enamel condition (p = 0.001). Demineralized enamel negatively affected the bond strength, with μSBS values approximately 50% lower than those obtained for sound enamel. SBU performed better in etch-and-rinse mode, and the bond strength found for SBU applied in self-etching mode was similar to that of CSE. Enamel etching with phosphoric acid improves the bond strength of a universal adhesive system to primary enamel. Demineralized primary enamel results in lower bond strength.

  4. Combining casein phosphopeptide-amorphous calcium phosphate with fluoride: synergistic remineralization potential of artificially demineralized enamel or not?

    Science.gov (United States)

    Elsayad, Iman; Sakr, Amal; Badr, Yahia

    2009-07-01

    Recaldent is a product of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). The remineralizing potential of CPP-ACP per se, or when combined with 0.22% Fl gel on artificially demineralized enamel using laser florescence, is investigated. Mesial surfaces of 15 sound human molars are tested using a He-Cd laser beam at 441.5 nm with 18-mW power as an excitation source on a suitable setup based on a Spex 750-M monochromator provided with a photomultiplier tube (PMT) for detection of collected autofluorescence from sound enamel. Mesial surfaces are subjected to demineralization for ten days. The spectra from demineralized enamel are measured. Teeth are divided into three groups according to the remineralizing regimen: group 1 Recaldent per se, group 2 Recaldent combined with fluoride gel and ACP, and group 3 artificial saliva as a positive control. After following these protocols for three weeks, the spectra from the remineralized enamel are measured. The spectra of enamel autofluorescence are recorded and normalized to peak intensity at about 540 nm to compare spectra from sound, demineralized, and remineralized enamel surfaces. A slight red shift occurred in spectra from demineralized enamel, while a blue shift may occur in remineralized enamel. Group 2 shows the highest remineralizing potential. Combining fluoride and ACP with CPP-ACP can give a synergistic effect on enamel remineralization.

  5. A comparative analysis of bleached and sound enamel structure through scanning electron microscopy and atomic force microscopy

    International Nuclear Information System (INIS)

    Saleem, A.; Kaleem, M.; Anwar, R.

    2015-01-01

    To analyze the effects of bleaching agent on enamel structure and to characterize the morphological and chemical changes in enamel due to bleaching. Study Design: Experimental study. Place and Duration of Study: School of Chemical and Material Engineering (SCME), NUST Islamabad from Feb to May 2013. Materials and Methods: Ten recently extracted pre molars between the 12-22 years age group were randomly assigned into two groups. Group one was a non-bleached control group with sound enamel. Group two was bleached with Everbrite In office tooth whitening system after specimen preparation, surface morphology was observed under SEM (scanned electron microscope) and AFM (Atomic force microscope). Results: The detrimental effects of hydrogen per-oxide on enamel were evident in bleached specimens under SEM, and AFM analysis. Conclusion: There were significant surface alterations found in the bleached specimens as compared to control group. However salivary buffering potentials could overcome the demineralizing effect of bleaching gel. (author)

  6. XRD and FTIR crystallinity indices in sound human tooth enamel and synthetic hydroxyapatite

    International Nuclear Information System (INIS)

    Reyes-Gasga, José; Martínez-Piñeiro, Esmeralda L.; Rodríguez-Álvarez, Galois; Tiznado-Orozco, Gaby E.; García-García, Ramiro

    2013-01-01

    The crystallinity index (CI) is a measure of the percentage of crystalline material in a given sample and it is also correlated to the degree of order within the crystals. In the literature two ways are reported to measure the CI: X-ray diffraction and infrared spectroscopy. Although the CI determined by these techniques has been adopted in the field of archeology as a structural order measure in the bone with the idea that it can help e.g. in the sequencing of the bones in chronological and/or stratigraphic order, some debate remains about the reliability of the CI values. To investigate similarities and differences between the two techniques, the CI of sound human tooth enamel and synthetic hydroxyapatite (HAP) was measured in this work by X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR), at room temperature and after heat treatment. Although the (CI) XRD index is related to the crystal structure of the samples and the (CI) FTIR index is related to the vibration modes of the molecular bonds, both indices showed similar qualitative behavior for heat-treated samples. At room temperature, the (CI) XRD value indicated that enamel is more crystalline than synthetic HAP, while (CI) FTIR indicated the opposite. Scanning (SEM) and transmission (TEM) images were also used to corroborate the measured CI values. - Highlights: • XRD and FTIR crystallinity indices for tooth enamel and synthetic HAP were obtained. • SEM and TEM images were more correlated with (CI) XRD than with (CI) FTIR . • Regardless of the temperature, (CI) XRD and (CI) FTIR showed similar behavior. • XRD and FTIR crystallinity indices resulted in a fast and qualitative measurement

  7. XRD and FTIR crystallinity indices in sound human tooth enamel and synthetic hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Reyes-Gasga, José, E-mail: jreyes@fisica.unam.mx [Instituto de Física, UNAM, Circuito de la Investigación Científica s/n., Cd. Universitaria, Coyoacán 04510, México, D.F. (Mexico); Martínez-Piñeiro, Esmeralda L., E-mail: esmemapi@gmail.com [Instituto de Física, UNAM, Circuito de la Investigación Científica s/n., Cd. Universitaria, Coyoacán 04510, México, D.F. (Mexico); Rodríguez-Álvarez, Galois, E-mail: galoisborre@yahoo.com [Instituto de Física, UNAM, Circuito de la Investigación Científica s/n., Cd. Universitaria, Coyoacán 04510, México, D.F. (Mexico); Tiznado-Orozco, Gaby E., E-mail: gab0409@yahoo.com.mx [Unidad Académica de Odontología, Universidad Autónoma de Nayarit, Edificio E7, Ciudad de la Cultura “Amado Nervo”, C.P. 63190 Tepic, Nayarit (Mexico); García-García, Ramiro, E-mail: ramiro@fisica.unam.mx [Instituto de Física, UNAM, Circuito de la Investigación Científica s/n., Cd. Universitaria, Coyoacán 04510, México, D.F. (Mexico); and others

    2013-12-01

    The crystallinity index (CI) is a measure of the percentage of crystalline material in a given sample and it is also correlated to the degree of order within the crystals. In the literature two ways are reported to measure the CI: X-ray diffraction and infrared spectroscopy. Although the CI determined by these techniques has been adopted in the field of archeology as a structural order measure in the bone with the idea that it can help e.g. in the sequencing of the bones in chronological and/or stratigraphic order, some debate remains about the reliability of the CI values. To investigate similarities and differences between the two techniques, the CI of sound human tooth enamel and synthetic hydroxyapatite (HAP) was measured in this work by X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR), at room temperature and after heat treatment. Although the (CI){sub XRD} index is related to the crystal structure of the samples and the (CI){sub FTIR} index is related to the vibration modes of the molecular bonds, both indices showed similar qualitative behavior for heat-treated samples. At room temperature, the (CI){sub XRD} value indicated that enamel is more crystalline than synthetic HAP, while (CI){sub FTIR} indicated the opposite. Scanning (SEM) and transmission (TEM) images were also used to corroborate the measured CI values. - Highlights: • XRD and FTIR crystallinity indices for tooth enamel and synthetic HAP were obtained. • SEM and TEM images were more correlated with (CI){sub XRD} than with (CI){sub FTIR}. • Regardless of the temperature, (CI){sub XRD} and (CI){sub FTIR} showed similar behavior. • XRD and FTIR crystallinity indices resulted in a fast and qualitative measurement.

  8. XRD and FTIR crystallinity indices in sound human tooth enamel and synthetic hydroxyapatite.

    Science.gov (United States)

    Reyes-Gasga, José; Martínez-Piñeiro, Esmeralda L; Rodríguez-Álvarez, Galois; Tiznado-Orozco, Gaby E; García-García, Ramiro; Brès, Etienne F

    2013-12-01

    The crystallinity index (CI) is a measure of the percentage of crystalline material in a given sample and it is also correlated to the degree of order within the crystals. In the literature two ways are reported to measure the CI: X-ray diffraction and infrared spectroscopy. Although the CI determined by these techniques has been adopted in the field of archeology as a structural order measure in the bone with the idea that it can help e.g. in the sequencing of the bones in chronological and/or stratigraphic order, some debate remains about the reliability of the CI values. To investigate similarities and differences between the two techniques, the CI of sound human tooth enamel and synthetic hydroxyapatite (HAP) was measured in this work by X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR), at room temperature and after heat treatment. Although the (CI)XRD index is related to the crystal structure of the samples and the (CI)FTIR index is related to the vibration modes of the molecular bonds, both indices showed similar qualitative behavior for heat-treated samples. At room temperature, the (CI)XRD value indicated that enamel is more crystalline than synthetic HAP, while (CI)FTIR indicated the opposite. Scanning (SEM) and transmission (TEM) images were also used to corroborate the measured CI values. © 2013.

  9. Laser and caries diagnosis: the state of the art and evaluation in vitro of the differences of the fluorescence between sound, carious and demineralized enamel

    International Nuclear Information System (INIS)

    Mendonca, Maria Angelica Lopes Chaves

    2001-01-01

    The aim of this study was to evaluate the methods for establishing dental caries diagnosis that make use of Laser light as source of illumination, establishing the 'state of the art'. Experimental observation of the differences among fluorescence of sound, demineralized and carious enamel by visible luminescent spectroscopy was also done. Six human teeth, extracted for clinical reasons were studied, and the results showed that the spectrum of carious enamel is different from the sound and demineralized ones. The differences are more evident relative to sond enamel and carious enamel, the same occurring between demineralized and carious enamel. The review of the literature aimed to make comparative considerations between QLF, LF and DELF; their effectiveness relative to traditional methods such as visual, visual with probe, radiography. It was verified that DELF was more sensitive, but could not discriminate between different degrees of mineral loss. QLF, compared to DIAGNOdent has the same sensitivity, but it is better for scientific purposes. The experimental part of the present study used on argon ion Laser to illuminated the teeth and signs of emission of fluorescence were captured by a PMT and then analyzed by a computer system with EG and G software. The results showed that the spectrum of carious enamel is different from the sound and demineralized. The differences are more evident in relation to sound and carious enamel, the same occurs between demineralized and carious enamel. (author)

  10. Effect of ultrasonic, sonic and rotating-oscillating powered toothbrushing systems on surface roughness and wear of white spot lesions and sound enamel: An in vitro study.

    Science.gov (United States)

    Hernandé-Gatón, Patrícia; Palma-Dibb, Regina Guenka; Silva, Léa Assed Bezerra da; Faraoni, Juliana Jendiroba; de Queiroz, Alexandra Mussolino; Lucisano, Marília Pacífico; Silva, Raquel Assed Bezerra da; Nelson Filho, Paulo

    2018-04-01

    To evaluate the effect of ultrasonic, sonic and rotating-oscillating powered toothbrushing systems on surface roughness and wear of white spot lesions and sound enamel. 40 tooth segments obtained from third molar crowns had the enamel surface divided into thirds, one of which was not subjected to toothbrushing. In the other two thirds, sound enamel and enamel with artificially induced white spot lesions were randomly assigned to four groups (n=10) : UT: ultrasonic toothbrush (Emmi-dental); ST1: sonic toothbrush (Colgate ProClinical Omron); ST2: sonic toothbrush (Sonicare Philips); and ROT: rotating-oscillating toothbrush (control) (Oral-B Professional Care Triumph 5000 with SmartGuide). The specimens were analyzed by confocal laser microscopy for surface roughness and wear. Data were analyzed statistically by paired t-tests, Kruskal-Wallis, two-way ANOVA and Tukey's post-test (α= 0.05). The different powered toothbrushing systems did not cause a significant increase in the surface roughness of sound enamel (P> 0.05). In the ROT group, the roughness of white spot lesion surface increased significantly after toothbrushing and differed from the UT group (Pspot lesion compared with sound enamel, and this group differed significantly from the ST1 group (Pspot lesion increased surface roughness and wear. None of the powered toothbrushing systems (ultrasonic, sonic and rotating-oscillating) tested caused significant alterations on sound dental enamel. However, conventional rotating-oscillating toothbrushing on enamel with white spot lesion increased surface roughness and wear. Copyright©American Journal of Dentistry.

  11. The efficacy of laser-assisted in-office bleaching and home bleaching on sound and demineralized enamel

    Science.gov (United States)

    Akbari, Majid; Mohammadpour, Sakineh

    2015-01-01

    Aims: This study investigated the effectiveness of laser-assisted in-office bleaching and home-bleaching in sound and demineralized enamel. Materials and Methods: The sample consisted of 120 freshly-extracted bovine incisors. Half of the specimens were stored in a demineralizing solution to induce white spot lesions. Following exposure to a tea solution for 7.5 days, the specimens were randomly assigned to 4 groups of 30 according to the type of enamel and the bleaching procedure employed. Groups 1 and 2 consisted of demineralized teeth subjected to in-office bleaching and home bleaching, whereas in groups 3 and 4, sound teeth were subjected to in-office and home bleaching, respectively. A diode laser (810 nm, 2 W, continuous wave, four times for 15 seconds each) was employed for assisting the in-office process. The color of the specimens was measured before (T1) and after (T2) staining and during (T3) and after (T4) the bleaching procedures using a spectrophotometer. The color change (ΔE) between different treatments stages was compared among the groups. Results: There were significant differences in the color change between T2 and T3 (ΔE T2–T3) and T2 and T4 (ΔE T2–T4) stages among the study groups (pbleaching (group 1) as compared to the other groups (Pbleaching could provide faster and greater whitening effect than home bleaching on stained demineralized enamel, but both procedures produced comparable results on sound teeth. PMID:26877590

  12. A Comparison of Fluoride Uptake by Sound Enamel Following Application of Sodium Fluoride Mouthrinses and APF Gels Produced in Iran with Standardized Foreign Samples

    Directory of Open Access Journals (Sweden)

    A Kowsari

    2002-02-01

    Full Text Available The goal of this investigation is to compare the extent of fluoride uptake by sound enamel following application of two commercial mouthrinses containing sodium fluoride (0.2% and a topical gel containing APF (1.23% produced in Iran with those of foreign standardized ones. Sixty extracted premolars were used. Each tooth was divided into two lingual and buccal halves, one half as control, the other one as experimental. Enamel biopsy technique (two- step acid etching was used to determine the concentration of fluoride and calcium in each sample. For data comparison and fluoride uptake estimation, the depths of layers with the use of linear regression analysis were standardized to 25 and 50um. The analysis showed that in Iranian mouthrinse no. 1, there is linear correlation between fluoride concentration and enamel depth, in both control and experimental group at the first and second layers, while, in other groups, this correlation was observed just at the first layer (superficial enamel layer. The greatest fluoride uptake was seen at Iranian mouthrinse no.2 and the least was seen at foreign mouthrinse no. 3. From among two APF gels, the greatest uptake was observed at gel no. 1 (Iranian. The results showed that all three Iranian products increase fluoride content of enamel, moreover the level of fluoride uptake, while applying Iranian products, in comparison with foreign ones, shows considerable increase.

  13. Laser and caries diagnosis: the state of the art and evaluation in vitro of the differences of the fluorescence between sound, carious and demineralized enamel; Laser e diagnostico de caries: estado da arte e avaliacao in vitro das diferencas de fluorescencia entre esmalte sadio, cariado e desmineralizado

    Energy Technology Data Exchange (ETDEWEB)

    Mendonca, Maria Angelica Lopes Chaves

    2001-07-01

    The aim of this study was to evaluate the methods for establishing dental caries diagnosis that make use of Laser light as source of illumination, establishing the 'state of the art'. Experimental observation of the differences among fluorescence of sound, demineralized and carious enamel by visible luminescent spectroscopy was also done. Six human teeth, extracted for clinical reasons were studied, and the results showed that the spectrum of carious enamel is different from the sound and demineralized ones. The differences are more evident relative to sond enamel and carious enamel, the same occurring between demineralized and carious enamel. The review of the literature aimed to make comparative considerations between QLF, LF and DELF; their effectiveness relative to traditional methods such as visual, visual with probe, radiography. It was verified that DELF was more sensitive, but could not discriminate between different degrees of mineral loss. QLF, compared to DIAGNOdent has the same sensitivity, but it is better for scientific purposes. The experimental part of the present study used on argon ion Laser to illuminated the teeth and signs of emission of fluorescence were captured by a PMT and then analyzed by a computer system with EG and G software. The results showed that the spectrum of carious enamel is different from the sound and demineralized. The differences are more evident in relation to sound and carious enamel, the same occurs between demineralized and carious enamel. (author)

  14. Laser and caries diagnosis: the state of the art and evaluation in vitro of the differences of the fluorescence between sound, carious and demineralized enamel; Laser e diagnostico de caries: estado da arte e avaliacao in vitro das diferencas de fluorescencia entre esmalte sadio, cariado e desmineralizado

    Energy Technology Data Exchange (ETDEWEB)

    Mendonca, Maria Angelica Lopes Chaves

    2001-07-01

    The aim of this study was to evaluate the methods for establishing dental caries diagnosis that make use of Laser light as source of illumination, establishing the 'state of the art'. Experimental observation of the differences among fluorescence of sound, demineralized and carious enamel by visible luminescent spectroscopy was also done. Six human teeth, extracted for clinical reasons were studied, and the results showed that the spectrum of carious enamel is different from the sound and demineralized ones. The differences are more evident relative to sond enamel and carious enamel, the same occurring between demineralized and carious enamel. The review of the literature aimed to make comparative considerations between QLF, LF and DELF; their effectiveness relative to traditional methods such as visual, visual with probe, radiography. It was verified that DELF was more sensitive, but could not discriminate between different degrees of mineral loss. QLF, compared to DIAGNOdent has the same sensitivity, but it is better for scientific purposes. The experimental part of the present study used on argon ion Laser to illuminated the teeth and signs of emission of fluorescence were captured by a PMT and then analyzed by a computer system with EG and G software. The results showed that the spectrum of carious enamel is different from the sound and demineralized. The differences are more evident in relation to sound and carious enamel, the same occurs between demineralized and carious enamel. (author)

  15. Does ozone enhance the remineralizing potential of nanohydroxyapatite on artificially demineralized enamel? A laser induced fluorescence study

    Science.gov (United States)

    Srinivasan, Samuelraj; Prabhu, Vijendra; Chandra, Subhash; Koshy, Shalini; Acharya, Shashidhar; Mahato, Krishna K.

    2014-02-01

    The present era of minimal invasive dentistry emphasizes the early detection and remineralization of initial enamel caries. Ozone has been shown to reverse the initial demineralization before the integrity of the enamel surface is lost. Nano-hydroxyapatite is a proven remineralizing agent for early enamel caries. In the present study, the effect of ozone in enhancing the remineralizing potential of nano-hydroxyapatite on artificially demineralized enamel was investigated using laser induced fluorescence. Thirty five sound human premolars were collected from healthy subjects undergoing orthodontic treatment. Fluorescence was recorded by exciting the mesial surfaces using 325 nm He-Cd laser with 2 mW power. Tooth specimens were subjected to demineralization to create initial enamel caries. Following which the specimens were divided into three groups, i.e ozone (ozonated water for 2 min), without ozone and artificial saliva. Remineralization regimen was followed for 3 weeks. The fluorescence spectra of the specimens were recorded from all the three experimental groups at baseline, after demineralization and remineralization. The average spectrum for each experimental group was used for statistical analysis. Fluorescence intensities of Ozone treated specimens following remineralization were higher than that of artificial saliva, and this difference was found to be statistically significant (P<0.0001). In a nutshell, ozone enhanced the remineralizing potential of nanohydroxyapatite, and laser induced fluorescence was found to be effective in assessing the surface mineral changes in enamel. Ozone can be considered an effective agent in reversing the initial enamel caries there by preventing the tooth from entering into the repetitive restorative cycle.

  16. Caries like lesion initiation in sound enamel following CW CO2 laser irradiation: an in vitro study

    International Nuclear Information System (INIS)

    Nafie, A.; Issam, A.; Ali, M. S. R.

    2005-01-01

    This Study aimed to asses the caries - preventive potential of various CW CO 2 laser parameters, and to explore the effect of the laser power density, and the exposure time on the varies inhibition activity. Materials and Methods: Extracted human premolar teeth were irradiated with three different power densities (7.95, 15.9 and 31.8) W/Cm 2 for three different exposure times (0.2, 0.4 and 0.8) sec of 10.6 μm CW CO 2 laser. All teeth were subjected to caries like lesion formation by 3.5 pH lactic acid for 21 days. The teeth after that were sectioned into ground cross section and the lesion depths were measured using a graticule polarizing microscope. CW CO 2 laser preventive treatments inhibit caries like lesion progression up to 44%. This effect was improved with: (1) Increased power density for each of the three exposure times. (2) Decreased exposure time for each of the three power densities within the limits of the previously listed laser parameters. Conclusion: (1) short exposure time of CW CO 2 laser results in a significant inhibition of the enamel caries like lesion formation. (2) The inhibitory effect depends upon the power density and the exposure time of the laser beam. (3) The optimal CW CO 2 laser parameters used for caries inhibition purpose is achieved with approximately 30 W/Cm 2 power density and 0.2 sec exposure time. (author)

  17. Enamel proteins mitigate mechanical and structural degradations in mature human enamel during acid attack

    Science.gov (United States)

    Lubarsky, Gennady V.; Lemoine, Patrick; Meenan, Brian J.; Deb, Sanjukta; Mutreja, Isha; Carolan, Patrick; Petkov, Nikolay

    2014-04-01

    A hydrazine deproteination process was used to investigate the role of enamel proteins in the acid erosion of mature human dental enamel. Bright field high resolution transmission electron micrographs and x-ray diffraction analysis show no crystallographic changes after the hydrazine treatment with similar nanoscale hydroxyapatite crystallite size and orientation for sound and de-proteinated enamel. However, the presence of enamel proteins reduces the erosion depth, the loss of hardness and the loss of structural order in enamel, following exposure to citric acid. Nanoindentation creep is larger for sound enamel than for deproteinated enamel but it reduces in sound enamel after acid attack. These novel results are consistent with calcium ion-mediated visco-elasticty in enamel matrix proteins as described previously for nacre, bone and dental proteins. They are also in good agreement with a previous double layer force spectroscopy study by the authors which found that the proteins electrochemically buffer enamel against acid attack. Finally, this suggests that acid attack, and more specifically dental erosion, is influenced by ionic permeation through the enamel layer and that it is mitigated by the enamel protein matrix.

  18. Enamel proteins mitigate mechanical and structural degradations in mature human enamel during acid attack

    International Nuclear Information System (INIS)

    Lubarsky, Gennady V; Lemoine, Patrick; Meenan, Brian J; Deb, Sanjukta; Mutreja, Isha; Carolan, Patrick; Petkov, Nikolay

    2014-01-01

    A hydrazine deproteination process was used to investigate the role of enamel proteins in the acid erosion of mature human dental enamel. Bright field high resolution transmission electron micrographs and x-ray diffraction analysis show no crystallographic changes after the hydrazine treatment with similar nanoscale hydroxyapatite crystallite size and orientation for sound and de-proteinated enamel. However, the presence of enamel proteins reduces the erosion depth, the loss of hardness and the loss of structural order in enamel, following exposure to citric acid. Nanoindentation creep is larger for sound enamel than for deproteinated enamel but it reduces in sound enamel after acid attack. These novel results are consistent with calcium ion-mediated visco-elasticty in enamel matrix proteins as described previously for nacre, bone and dental proteins. They are also in good agreement with a previous double layer force spectroscopy study by the authors which found that the proteins electrochemically buffer enamel against acid attack. Finally, this suggests that acid attack, and more specifically dental erosion, is influenced by ionic permeation through the enamel layer and that it is mitigated by the enamel protein matrix. (papers)

  19. Sound

    CERN Document Server

    Robertson, William C

    2003-01-01

    Muddled about what makes music? Stuck on the study of harmonics? Dumbfounded by how sound gets around? Now you no longer have to struggle to teach concepts you really don t grasp yourself. Sound takes an intentionally light touch to help out all those adults science teachers, parents wanting to help with homework, home-schoolers seeking necessary scientific background to teach middle school physics with confidence. The book introduces sound waves and uses that model to explain sound-related occurrences. Starting with the basics of what causes sound and how it travels, you'll learn how musical instruments work, how sound waves add and subtract, how the human ear works, and even why you can sound like a Munchkin when you inhale helium. Sound is the fourth book in the award-winning Stop Faking It! Series, published by NSTA Press. Like the other popular volumes, it is written by irreverent educator Bill Robertson, who offers this Sound recommendation: One of the coolest activities is whacking a spinning metal rod...

  20. Demineralization of Enamel in Primary Second Molars Related to Properties of the Enamel

    Directory of Open Access Journals (Sweden)

    N. Sabel

    2012-01-01

    Full Text Available Enamel structure is of importance in demineralization. Differences in porosity in enamel effect the rate of demineralization, seen between permanent and deciduous teeth. Individual differences have been shown in the mean mineral concentration values in enamel, the role of this in demineralization is not thoroughly investigated. The aim of this study was to study variations of depths of artificial lesions of demineralization and to analyze the depth in relation to variations in the chemical and mineral composition of the enamel. A demineralized lesion was created in second primary molars from 18 individuals. Depths of lesions were then related to individual chemical content of the enamel. Enamel responded to demineralization with different lesion depths and this was correlated to the chemical composition. The carbon content in sound enamel was shown to be higher where lesions developed deeper. The lesion was deeper when the degree of porosity of the enamel was higher.

  1. Effects of ultrasonic instrumentation on enamel surfaces with various defects.

    Science.gov (United States)

    Kim, S-Y; Kang, M-K; Kang, S-M; Kim, H-E

    2018-05-01

    The aim of this study was to analyse the enamel damage caused by ultrasonic scaling of teeth with various enamel conditions that are difficult to identify by visual inspection, such as enamel cracks, early caries and resin restorations. In total, 120 tooth surfaces were divided into 4 experimental groups using a quantitative light-induced fluorescence-digital system: sound enamel group, enamel cracks group, early caries group and resin restoration group. A skilled dental hygienist performed ultrasonic scaling under a standardized set of conditions: a ≤ 15° angle between the scaler tip and tooth surface and 40-80 g of lateral pressure at the rate of 12 times/10 s. Following scaling, the depth of enamel damage was measured using a surface profilometer and observed using scanning electron microscopy (SEM). The damage depth was the greatest in the enamel cracks group (37.63 ± 34.42 μm), followed by the early caries group (26.81 ± 8.67 μm), resin restoration group (19.63 ± 6.73 μm) and the sound enamel group (17.00 ± 5.66 μm). The damage depth was significantly deeper in the enamel cracks and early caries groups than in the sound enamel group (P enamel loss in the enamel cracks, early caries and resin restoration groups. The results of this study suggest that ultrasonic scaling can cause further damage to teeth with enamel cracks, early caries and resin restorations. Therefore, accurate identification of tooth conditions and calculus before the initiation of ultrasonic scaling is necessary to minimize damage. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Microtensile bond strength to enamel affected by hypoplastic amelogenesis imperfecta.

    Science.gov (United States)

    Yaman, Batu Can; Ozer, Fusun; Cabukusta, Cigdem Sozen; Eren, Meltem M; Koray, Fatma; Blatz, Markus B

    2014-02-01

    This study compared the microtensile bond strengths (μTBS) of two different self-etching (SE) and etchand- rinse (ER) adhesive systems to enamel affected by hypoplastic amelogenesis imperfecta (HPAI) and analyzed the enamel etching patterns created by the two adhesive systems using scanning electron microscopy (SEM). Sixteen extracted HPAI-affected molars were used for the bond strength tests and 2 molars were examined under SEM for etching patterns. The control groups consisted of 12 healthy third molars for μTBS tests and two molars for SEM. Mesial and distal surfaces of the teeth were slightly ground flat. The adhesive systems and composite resin were applied to the flat enamel surfaces according to the manufacturers' instructions. The tooth slabs containing composite resin material on their mesial and distal surfaces were cut in the mesio-distal direction with a slow-speed diamond saw. The slabs were cut again to obtain square, 1-mm-thick sticks. Finally, each stick was divided into halves and placed in the μTBS tester. Bond strength tests were performed at a speed of 0.5 mm/min. Data were analyzed with two-way ANOVA and Tukey's tests. There was no significant difference between the bond strength values of ER and SE adhesives (p > 0.05). However, significant differences were found between HPAI and control groups (p systems provide similar bond strengths to HPAI-affected enamel surfaces.

  3. Natural enamel caries in polarized light microscopy: differences in histopathological features derived from a qualitative versus a quantitative approach to interpret enamel birefringence.

    Science.gov (United States)

    De Medeiros, R C G; Soares, J D; De Sousa, F B

    2012-05-01

    Lesion area measurement of enamel caries using polarized light microscopy (PLM) is currently performed in a large number of studies, but measurements are based mainly on a mislead qualitative interpretation of enamel birefringence in a single immersion medium. Here, five natural enamel caries lesions are analysed by microradiography and in PLM, and the differences in their histopathological features derived from a qualitative versus a quantitative interpretation of enamel birefringence are described. Enamel birefringence in different immersion media (air, water and quinoline) is interpreted by both qualitative and quantitative approaches, the former leading to an underestimation of the depth of enamel caries mainly when the criterion of validating sound enamel as a negatively birefringent area in immersion in water is used (a current common practice in dental research). Procedures to avoid the shortcomings of a qualitative interpretation of enamel birefringence are presented and discussed. © 2012 The Authors Journal of Microscopy © 2012 Royal Microscopical Society.

  4. Thalamic changes with mesial temporal sclerosis: MRI

    Energy Technology Data Exchange (ETDEWEB)

    Deasy, N.P.; Jarosz, J.M.; Cox, T.C.S. [Department of Neuroradiology, King' s College Hospital, London (United Kingdom); Elwes, R.C.D. [Department of Neurology, King' s College Hospital, London (United Kingdom); Polkey, C.E. [Department of Neurosurgery, King' s College and Maudsley Hospitals, London (United Kingdom)

    2000-05-01

    We reviewed the preoperative images of 28 patients with pathologically proven mesial temporal sclerosis, to assess thalamic asymmetry and signal change. A further 25 nonsurgical patients with temporal lobe epilepsy and unequivocal, unilateral changes of mesial temporal sclerosis, and 20 controls, were also reviewed. None of the control group had unequivocal asymmetry of the thalamus. There was an ipsilateral asymmetrically small thalamus in five (18 %) of the surgical group and in three (12 %) of the nonsurgical patients. In four cases there was thalamic signal change. In three patients with thalamic volume loss there was ipsilateral hemiatrophy. All patients with an asymmetrically small thalamus had an asymmetrically small fornix and all but one a small ipsilateral mamillary body. (orig.)

  5. Near-UV laser treatment of extrinsic dental enamel stains.

    Science.gov (United States)

    Schoenly, J E; Seka, W; Featherstone, J D B; Rechmann, P

    2012-04-01

    The selective ablation of extrinsic dental enamel stains using a 400-nm laser is evaluated at several fluences for completely removing stains with minimal damage to the underlying enamel. A frequency-doubled Ti:sapphire laser (400-nm wavelength, 60-nanosecond pulse duration, 10-Hz repetition rate) was used to treat 10 extracted human teeth with extrinsic enamel staining. Each tooth was irradiated perpendicular to the surface in a back-and-forth motion over a 1-mm length using an ∼300-µm-diam 10th-order super-Gaussian beam with fluences ranging from 0.8 to 6.4 J/cm(2) . Laser triangulation determined stain depth and volume removed by measuring 3D surface images before and after irradiation. Scanning electron microscopy evaluated the surface roughness of enamel following stain removal. Fluorescence spectroscopy measured spectra of unbleached and photobleached stains in the spectral range of 600-800 nm. Extrinsic enamel stains are removed with laser fluences between 0.8 and 6.4 J/cm(2) . Stains removed on sound enamel leave behind a smooth enamel surface. Stain removal in areas with signs of earlier cariogenic acid attacks resulted in isolated and randomly located laser-induced, 50-µm-diam enamel pits. These pits contain 0.5-µm diam, smooth craters indicative of heat transfer from the stain to the enamel and subsequent melting and water droplet ejection. Ablation stalling of enamel stains is typically observed at low fluences (Laser ablation of extrinsic enamel stains at 400 nm is observed to be most efficient above 3 J/cm(2) with minimal damage to the underlying enamel. Unsound underlying enamel is also observed to be selectively removed after irradiation. Copyright © 2012 Wiley Periodicals, Inc.

  6. On the critical parameters that regulate the deformation behaviour of tooth enamel.

    Science.gov (United States)

    Xie, Zonghan; Swain, Michael; Munroe, Paul; Hoffman, Mark

    2008-06-01

    Tooth enamel is the hardest tissue in the human body with a complex hierarchical structure. Enamel hypomineralisation--a developmental defect--has been reported to cause a marked reduction in the mechanical properties of enamel and loss of dental function. We discover a distinctive difference in the inelastic deformation mechanism between sound and hypomineralised enamels that is apparently controlled by microstructural variation. For sound enamel, when subjected to mechanical forces the controlling deformation mechanism was distributed shearing within nanometre thick protein layer between its constituent mineral crystals; whereas for hypomineralised enamel microcracking and subsequent crack growth were more evident in its less densely packed microstructure. We develop a mechanical model that not only identifies the critical parameters, i.e., the thickness and shear properties of enamels, that regulate the mechanical behaviour of enamel, but also explains the degradation of hypomineralised enamel as manifested by its lower resistance to deformation and propensity for catastrophic failure. With support of experimental data, we conclude that for sound enamel an optimal microstructure has been developed that endows enamel with remarkable structural integrity for durable mechanical function.

  7. Amelogenin and Enamel Biomimetics

    Science.gov (United States)

    Ruan, Qichao; Moradian-Oldak, Janet

    2015-01-01

    Mature tooth enamel is acellular and does not regenerate itself. Developing technologies that rebuild tooth enamel and preserve tooth structure is therefore of great interest. Considering the importance of amelogenin protein in dental enamel formation, its ability to control apatite mineralization in vitro, and its potential to be applied in fabrication of future bio-inspired dental material this review focuses on two major subjects: amelogenin and enamel biomimetics. We review the most recent findings on amelogenin secondary and tertiary structural properties with a focus on its interactions with different targets including other enamel proteins, apatite mineral, and phospholipids. Following a brief overview of enamel hierarchical structure and its mechanical properties we will present the state-of-the-art strategies in the biomimetic reconstruction of human enamel. PMID:26251723

  8. Mesial temporal sclerosis in children Esclerose mesial temporal em crianças

    Directory of Open Access Journals (Sweden)

    Eliana Maria Domingues Brandão

    2007-12-01

    Full Text Available Mesial temporal sclerosis is the most frequent cause of drug-resistant temporal lobe epilepsy but has a satisfactory response to surgery, and is considered infrequent in children. OBJECTIVE: To evaluate the clinical, electrographic and radiological spectrum of the disease in children. METHOD: Retrospective study by review of charts of 44 children with a diagnosis of mesial temporal sclerosis on magnetic resonance imaging, attended at the "Hospital das Clínicas" of the University of São Paulo Faculty of Medicine. RESULTS: Febrile seizure was identified in the history of 54% of the patients. Injuries at the left side predominated in patients with schooling difficulties (p=0.049, in those with the first seizures between six months and five years (p=0.021 and in those with complex febrile seizure (p=0.032. Thirteen patients were submitted to surgery and of these, eight remained without seizures. CONCLUSION: Febrile seizure may be related in a more direct way to the presence of left-side mesial temporal sclerosis.Em adultos, esclerose mesial temporal é a causa mais freqüente de epilepsia do lobo temporal intratável por medicamentos e que responde satisfatoriamente a cirurgia, sendo considerada pouco freqüente em criança. OBJETIVO: Avaliar o espectro clínico, eletrográfico e radiológico desta patologia em crianças. MÉTODO: Estudo retrospectivo, por revisão de prontuário de 44 crianças com diagnóstico de esclerose mesial temporal na ressonância magnética, atendidos no Hospital das Clínicas da Faculdade de Medicina de São Paulo. RESULTADO: Foi identificado que 54% dos pacientes apresentaram antecedente de crise febril. Lesão no lado esquerdo predominou nos pacientes com dificuldade escolar (p=0.049, naqueles com primeiras crises entre seis meses e cinco anos (p=0,021 e naqueles com crise febril complicada (p=0,032. Treze pacientes foram operados, dos quais oito ficaram livres de crises. CONCLUSÃO: Crise febril pode estar

  9. Trace Elements in Human Tooth Enamel

    Energy Technology Data Exchange (ETDEWEB)

    Nixon, G. S. [Turner Dental School, University Of Manchester, Manchester (United Kingdom); Smith, H.; Livingston, H. D. [Department of Forensic Medicine, University Of Glasgow, Glasgow (United Kingdom)

    1967-10-15

    The trace elements are considered to play a role in the resistance of teeth to dental caries. The exact mechanism by which they act has not yet been fully established. Estimations of trace elements have been undertaken in sound human teeth. By means of activation analysis it has been possible to determine trace element concentrations in different layers of enamel in the same tooth. The concentrations of the following elements have been determined: arsenic, antimony, copper, zinc, manganese, mercury, molybdenum and vanadium. The distribution of trace elements in enamel varies from those with a narrow range, such as manganese, to those with a broad range, such as antimony. The elements present in the broad range are considered to be non-essential and their presence is thought to result from a chance incorporation into the enamel. Those in the narrow range appear to be essential trace elements and are present in amounts which do not vary unduly from other body tissues. Only manganese and zinc were found in higher concentrations in the surface layer of enamel compared with the inner layers. The importance of the concentration of trace elements on this surface layer of enamel is emphasized as this layer is the site of the first attack by the carious process. (author)

  10. Maturation Stage Enamel Malformations in Amtn and Klk4 Null Mice

    Science.gov (United States)

    Nunez, Stephanie M.; Chun, Yong-Hee P.; Ganss, Bernhard; Hu, Yuanyuan; Richardson, Amelia S; Schmitz, James E.; Fajardo, Roberto; Yang, Jie; Hu, Jan C-C.; Simmer, James P.

    2015-01-01

    Amelotin (AMTN) and kallikrein-4 (KLK4) are secreted proteins specialized for enamel biomineralization. We characterized enamel from wild-type, Amtn−/−, Klk4−/−, Amtn+/−Klk4+/− and Amtn−/−Klk4−/− mice to gain insights into AMTN and KLK4 functions during amelogenesis. All of the null mice were healthy and fertile. The mandibular incisors in Amtn−/−, Klk4−/− and Amtn−/−Klk4−/− mice were chalky-white and chipped. No abnormalities except in enamel were observed, and no significant differences were detected in enamel thickness or volume, or in rod decussation. Micro-computed tomography (µCT) maximum intensity projections localized the onset of enamel maturation in wild-type incisors distal to the first molar, but mesial to this position in Amtn−/−, Klk4−/− and Amtn−/−Klk4−/− mice, demonstrating a delay in enamel maturation in Amtn−/− incisors. Micro-CT detected significantly reduced enamel mineral density (2.5 and 2.4 gHA/cm3) in the Klk4−/− and Amtn−/−Klk4−/− mice respectively, compared with wild-type enamel (3.1 gHA/cm3). Backscatter scanning electron microscopy showed that mineral density progressively diminished with enamel depth in the Klk4−/− and Amtn−/−Klk4−/− mice. Knoop hardness of Amtn−/− outer enamel was significantly reduced relative to the wild-type and was not as hard as the middle or inner enamel. Klk4−/− enamel hardness was significantly reduced at all levels, but the outer enamel was significantly harder than the inner and middle enamel. Thus the hardness patterns of the Amtn−/− and Klk4−/− mice were distinctly different, while the Amtn−/−Klk4−/− outer enamel was not as hard as in the Amtn−/− and Klk4−/− mice. We conclude that AMTN and KLK4 function independently, but are both necessary for proper enamel maturation. PMID:26620968

  11. Endocytosis and Enamel Formation

    Directory of Open Access Journals (Sweden)

    Cong-Dat Pham

    2017-07-01

    Full Text Available Enamel formation requires consecutive stages of development to achieve its characteristic extreme mineral hardness. Mineralization depends on the initial presence then removal of degraded enamel proteins from the matrix via endocytosis. The ameloblast membrane resides at the interface between matrix and cell. Enamel formation is controlled by ameloblasts that produce enamel in stages to build the enamel layer (secretory stage and to reach final mineralization (maturation stage. Each stage has specific functional requirements for the ameloblasts. Ameloblasts adopt different cell morphologies during each stage. Protein trafficking including the secretion and endocytosis of enamel proteins is a fundamental task in ameloblasts. The sites of internalization of enamel proteins on the ameloblast membrane are specific for every stage. In this review, an overview of endocytosis and trafficking of vesicles in ameloblasts is presented. The pathways for internalization and routing of vesicles are described. Endocytosis is proposed as a mechanism to remove debris of degraded enamel protein and to obtain feedback from the matrix on the status of the maturing enamel.

  12. Surgical Considerations of Intractable Mesial Temporal Lobe Epilepsy

    Science.gov (United States)

    Boling, Warren W.

    2018-01-01

    Surgery of temporal lobe epilepsy is the best opportunity for seizure freedom in medically intractable patients. The surgical approach has evolved to recognize the paramount importance of the mesial temporal structures in the majority of patients with temporal lobe epilepsy who have a seizure origin in the mesial temporal structures. For those individuals with medically intractable mesial temporal lobe epilepsy, a selective amygdalohippocampectomy surgery can be done that provides an excellent opportunity for seizure freedom and limits the resection to temporal lobe structures primarily involved in seizure genesis. PMID:29461485

  13. Surgical Considerations of Intractable Mesial Temporal Lobe Epilepsy

    Directory of Open Access Journals (Sweden)

    Warren W. Boling

    2018-02-01

    Full Text Available Surgery of temporal lobe epilepsy is the best opportunity for seizure freedom in medically intractable patients. The surgical approach has evolved to recognize the paramount importance of the mesial temporal structures in the majority of patients with temporal lobe epilepsy who have a seizure origin in the mesial temporal structures. For those individuals with medically intractable mesial temporal lobe epilepsy, a selective amygdalohippocampectomy surgery can be done that provides an excellent opportunity for seizure freedom and limits the resection to temporal lobe structures primarily involved in seizure genesis.

  14. Shear bond strengths of three glass ionomer cements to enamel and dentine

    NARCIS (Netherlands)

    Carvalho, T.S.; van Amerongen, W.E.; de Gee, A.; Bönecker, M.; Sampaio, F.C.

    2011-01-01

    Objectives: The shear bond strength of three glass ionomer cements (GIC) to enamel and dentine was evaluated. Study Design: Sound permanent human molars (n=12) were grinded perpendicular to their axial axes, exposing smooth, flat enamel and dentine surfaces. The teeth were embedded in resin and

  15. MicroCT study on the enamel mineral density of primary molars

    NARCIS (Netherlands)

    Elfrink, M.E.C.; Kalin, K.; van Ruijven, L.J.; ten Cate, J.M.; Veerkamp, J.S.J.

    2016-01-01

    Aim The aim of this study is to report on the mineral density of the enamel of primary molars related to the age of the child and to compare the mineral density of sound and carious enamel in those molars. Materials and methods This study included 23 children and 41 extracted primary molars. The

  16. Atypical handedness in mesial temporal lobe epilepsy.

    Science.gov (United States)

    Doležalová, Irena; Schachter, Steven; Chrastina, Jan; Hemza, Jan; Hermanová, Markéta; Rektor, Ivan; Pažourková, Marta; Brázdil, Milan

    2017-07-01

    The main aim of our study was to investigate the handedness of patients with mesial temporal lobe epilepsy (MTLE). We also sought to identify clinical variables that correlated with left-handedness in this population. Handedness (laterality quotient) was assessed in 73 consecutive patients with MTLE associated with unilateral hippocampal sclerosis (HS) using the Edinburgh Handedness Inventory. Associations between right- and left-handedness and clinical variables were investigated. We found that 54 (74.0%) patients were right-handed, and 19 (26%) patients were left-handed. There were 15 (36.6%) left-handed patients with left-sided seizure onset compared to 4 (12.5%) left-handed patients with right-sided seizure onset (p=0.030). Among patients with left-sided MTLE, age at epilepsy onset was significantly correlated with handedness (8years of age [median; min-max 0.5-17] in left-handers versus 15years of age [median; min-max 3-30] in right-handers (p<0.001). Left-sided MTLE is associated with atypical handedness, especially when seizure onset occurs during an active period of brain development, suggesting a bi-hemispheric neuroplastic process for establishing motor dominance in patients with early-onset left-sided MTLE. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Enamel surface remineralization: Using synthetic nanohydroxyapatite

    Directory of Open Access Journals (Sweden)

    J Shanti Swarup

    2012-01-01

    Full Text Available Objective: The purpose of this study was to evaluate the effects of synthetically processed hydroxyapatite particles in remineralization of the early enamel lesions in comparison with 2% sodium fluoride. Materials and Methods: Thirty sound human premolars were divided into nanohydroxyapatite group (n0 = 15 and the sodium fluoride group (n = 15. The specimens were subjected to demineralization before being coated with 10% aqueous slurry of 20 nm nanohydroxyapatite or 2% sodium fluoride. The remineralizing efficacy of the materials was evaluated using surface microhardness (SMH measurements, scanning microscopic analysis and analysis of the Ca/P ratio of the surface enamel. Data analysis was carried out using paired t-test and independent t-test. Results: The results showed that the nanohydroxyapatite group produced a surface morphology close to the biologic enamel, the increase in mineral content (Ca/P ratio was more significant in the nanohydroxyapatite group ( P 0.05. Conclusion: The use of biomimetic nanohydroxyapatite as a remineralizing agent holds promise as a new synthetic enamel biocompatible material to repair early carious lesions.

  18. Protein- mediated enamel mineralization

    Science.gov (United States)

    Moradian-Oldak, Janet

    2012-01-01

    Enamel is a hard nanocomposite bioceramic with significant resilience that protects the mammalian tooth from external physical and chemical damages. The remarkable mechanical properties of enamel are associated with its hierarchical structural organization and its thorough connection with underlying dentin. This dynamic mineralizing system offers scientists a wealth of information that allows the study of basic principals of organic matrix-mediated biomineralization and can potentially be utilized in the fields of material science and engineering for development and design of biomimetic materials. This chapter will provide a brief overview of enamel hierarchical structure and properties as well as the process and stages of amelogenesis. Particular emphasis is given to current knowledge of extracellular matrix protein and proteinases, and the structural chemistry of the matrix components and their putative functions. The chapter will conclude by discussing the potential of enamel for regrowth. PMID:22652761

  19. Structural, mechanical and chemical evaluation of molar-incisor hypomineralization-affected enamel: A systematic review.

    Science.gov (United States)

    Elhennawy, Karim; Manton, David John; Crombie, Felicity; Zaslansky, Paul; Radlanski, Ralf J; Jost-Brinkmann, Paul-Georg; Schwendicke, Falk

    2017-11-01

    To systematically assess and contrast reported differences in microstructure, mineral density, mechanical and chemical properties between molar-incisor-hypomineralization-affected (MIH) enamel and unaffected enamel. Studies on extracted human teeth, clinically diagnosed with MIH, reporting on the microstructure, mechanical properties or the chemical composition and comparing them to unaffected enamel were reviewed. Electronic databases (PubMed, Embase and Google Scholar) were screened; hand searches and cross-referencing were also performed. Twenty-two studies were included. Fifteen studies on a total of 201 teeth investigated the structural properties, including ten (141 teeth) on microstructure and seven (60 teeth) on mineral density; six (29 teeth) investigated the mechanical properties and eleven (87 teeth) investigated the chemical properties of MIH-affected enamel and compared them to unaffected enamel. Studies unambiguously found a reduction in mineral quantity and quality (reduced Ca and P content), reduction of hardness and modulus of elasticity (also in the clinically sound-appearing enamel bordering the MIH-lesion), an increase in porosity, carbon/carbonate concentrations and protein content compared to unaffected enamel. were ambiguous with regard to the extent of the lesion through the enamel to the enamel-dentin junction, the Ca/P ratio and the association between clinical appearance and defect severity. There is an understanding of the changes related to MIH-affected enamel. The association of these changes with the clinical appearance and resulting implications for clinical management are unclear. MIH-affected enamel is greatly different from unaffected enamel. This has implications for management strategies. The possibility of correlating the clinical appearance of MIH-affected enamel with the severity of enamel changes and deducing clinical concepts (risk stratification etc.) is limited. Crown Copyright © 2017. Published by Elsevier Ltd. All

  20. Relationship between microhardness and fluorine contents on tooth enamel determined by PIGE analysis

    International Nuclear Information System (INIS)

    Ma, D.S.; Paik, D.I.; Park, D.Y.; Moon, H.S.; Chang, Y.I.; Kim, J.B.

    1997-01-01

    The remineralization effect of fluoride has been measured by surface microhardness on tooth enamel. The purpose of this study was to investigate the relationship between microhardness and fluorine concentration on tooth enamel. Twelve sound bovine enamel specimens were prepared and immersed in 0.05% NaF solution for 1, 3, 6, 24 and 36 hours, respectively. The concentration of fluorine in specimens were measured by PIGE analysis and surface microhardness of each specimen was measured by surface microhardness tester. Fluorine concentration was increased by immersing time. There was no change in microhardness of each specimen by fluorine content. The results of this study suggest that there was no relationship between the fluorine concentration and surface microhardness in sound tooth enamel. PIGE analysis can be used effectively to assess the remineralization effect of fluorine content in tooth enamel. (author)

  1. Laser investigation of the non-uniformity of fluorescent species in dental enamel

    Science.gov (United States)

    Tran, Stephanie U.; Ridge, Jeremy S.; Nelson, Leonard Y.; Seibel, Eric J.

    In the present study, artificial type I and type II erosions were created on dental specimen using acetic acid and EDTA respectively. Specimens were prepared by etching extracted teeth samples in acid to varying degrees, after which the absolute fluorescence intensity ratio of the etched enamel relative to sound enamel was recorded for each specimen using 405 and 532 nm laser excitation. Results showed differences in the fluorescence ratio of etched to sound enamel for type I and II erosions. These findings suggest a non-uniform distribution of fluorescent species in the interprismatic region as compared to the prismatic region.

  2. Bond strength of a pit-and-fissure sealant associated to etch-and-rinse and self-etching adhesive systems to saliva-contaminated enamel: individual vs. simultaneous light curing.

    Science.gov (United States)

    Gomes-Silva, Jaciara Miranda; Torres, Carolina Paes; Contente, Marta Maria Martins Giamatei; Oliveira, Maria Angélica Hueb de Menezes; Palma-Dibb, Regina Guenka; Borsatto, Maria Cristina

    2008-01-01

    This study evaluated in vitro the shear bond strength (SBS) of a resin-based pit-and-fissure sealant [Fluroshield (F), Dentsply/Caulk] associated with either an etch-and-rinse [Adper Single Bond 2 (SB), 3M/ESPE] or a self-etching adhesive system [Clearfil S3 Bond (S3), Kuraray Co., Ltd.] to saliva-contaminated enamel, comparing two curing protocols: individual light curing of the adhesive system and the sealant or simultaneous curing of both materials. Mesial and distal enamel surfaces from 45 sound third molars were randomly assigned to 6 groups (n=15), according to the bonding technique: I - F was applied to 37% phosphoric acid etched enamel. The other groups were contaminated with fresh human saliva (0.01 mL; 10 s) after acid etching: II - SB and F were light cured separately; III - SB and F were light cured together; IV - S3 and F were light cured separately; V - S3 and F were light cured simultaneously; VI - F was applied to saliva-contaminated, acid-etched enamel without an intermediate bonding agent layer. SBS was tested to failure in a universal testing machine at 0.5 mm/min. Data were analyzed by one-way ANOVA and Fisher's test (alpha=0.05).The debonded specimens were examined with a stereomicroscope to assess the failure modes. Three representative specimens from each group were observed under scanning electron microscopy for a qualitative analysis. Mean SBS in MPa were: I-12.28 (+/-4.29); II-8.57 (+/-3.19); III-7.97 (+/-2.16); IV-12.56 (+/-3.11); V-11.45 (+/-3.77); and VI-7.47 (+/-1.99). In conclusion, individual or simultaneous curing of the intermediate bonding agent layer and the resin sealant did not seem to affect bond strength to saliva-contaminated enamel. S3/F presented significantly higher SBS than the that of the groups treated with SB etch-and-rinse adhesive system and similar SBS to that of the control group, in which the sealant was applied under ideal dry, noncontaminated conditions.

  3. Functional connectivity between right and left mesial temporal structures.

    Science.gov (United States)

    Lacuey, Nuria; Zonjy, Bilal; Kahriman, Emine S; Kaffashi, Farhad; Miller, Jonathan; Lüders, Hans O

    2015-09-01

    The aim of this study is to investigate functional connectivity between right and left mesial temporal structures using cerebrocerebral evoked potentials. We studied seven patients with drug-resistant focal epilepsy who were explored with stereotactically implanted depth electrodes in bilateral hippocampi. In all patients cerebrocerebral evoked potentials evoked by stimulation of the fornix were evaluated as part of a research project assessing fornix stimulation for control of hippocampal seizures. Stimulation of the fornix elicited responses in the ipsilateral hippocampus in all patients with a mean latency of 4.6 ms (range 2-7 ms). Two patients (29 %) also had contralateral hippocampus responses with a mean latency of 7.5 ms (range 5-12 ms) and without involvement of the contralateral temporal neocortex or amygdala. This study confirms the existence of connections between bilateral mesial temporal structures in some patients and explains seizure discharge spreading between homotopic mesial temporal structures without neocortical involvement.

  4. Radiosurgery in the Management of Intractable Mesial Temporal Lobe Epilepsy.

    Science.gov (United States)

    Peñagarícano, José; Serletis, Demitre

    2015-09-01

    Mesial temporal lobe epilepsy (MTLE) describes recurrent seizure activity originating from the depths of the temporal lobe. MTLE patients who fail two trials of medication now require testing for surgical candidacy at an epilepsy center. For these individuals, temporal lobectomy offers the greatest likelihood for seizure-freedom (up to 80-90%); unfortunately, this procedure remains largely underutilized. Moreover, for select patients unable to tolerate open surgery, novel techniques are emerging for selective ablation of the mesial temporal structures, including stereotactic radiosurgery (SRS). We present here a review of SRS as a potential therapy for MTLE, when open surgery is not an option.

  5. Sound and sound sources

    DEFF Research Database (Denmark)

    Larsen, Ole Næsbye; Wahlberg, Magnus

    2017-01-01

    There is no difference in principle between the infrasonic and ultrasonic sounds, which are inaudible to humans (or other animals) and the sounds that we can hear. In all cases, sound is a wave of pressure and particle oscillations propagating through an elastic medium, such as air. This chapter...... is about the physical laws that govern how animals produce sound signals and how physical principles determine the signals’ frequency content and sound level, the nature of the sound field (sound pressure versus particle vibrations) as well as directional properties of the emitted signal. Many...... of these properties are dictated by simple physical relationships between the size of the sound emitter and the wavelength of emitted sound. The wavelengths of the signals need to be sufficiently short in relation to the size of the emitter to allow for the efficient production of propagating sound pressure waves...

  6. Effects of Different Radiation Doses on the Bond Strengths of Two Different Adhesive Systems to Enamel and Dentin.

    Science.gov (United States)

    da Cunha, Sandra Ribeiro de Barros; Ramos, Pedro Augusto Minorin Mendes; Haddad, Cecília Maria Kalil; da Silva, João Luis Fernandes; Fregnani, Eduardo Rodrigues; Aranha, Ana Cecília Corrêa

    2016-01-01

    To evaluate the effects of three different radiation doses on the bond strengths of two different adhesive systems to enamel and dentin. Eighty human third molars were randomly divided into four groups (n = 20) according to the radiation dose (control/no radiation, 20 Gy, 40 Gy, and 70 Gy). The teeth were sagittally sectioned into three slices: one mesial and one distal section containing enamel and one middle section containing dentin. The sections were then placed in the enamel and dentin groups, which were further divided into two subgroups (n = 10) according to the adhesive used. Three restorations were performed in each tooth (one per section) using Adper Single Bond 2 (3M ESPE) or Universal Single Bond (3M ESPE) adhesive system and Filtek Z350 XT (3M ESPE) resin composite and subjected to the microshear bond test. Data were analyzed using a two-way ANOVA followed by Tukey's test. Failure modes were examined under a stereoscopic loupe. Radiotherapy did not affect the bond strengths of the adhesives to either enamel or dentin. In dentin, the Universal Single Bond adhesive system showed higher bond strength values when compared with the Adper Single Bond adhesive system. More adhesive failures were observed in the enamel for all radiation doses and adhesives. Radiotherapy did not influence the bond strength to enamel or dentin, irrespective of the adhesive or radiation dose used.

  7. Enamel formation and amelogenesis imperfecta.

    Science.gov (United States)

    Hu, Jan C-C; Chun, Yong-Hee P; Al Hazzazzi, Turki; Simmer, James P

    2007-01-01

    Dental enamel is the epithelial-derived hard tissue covering the crowns of teeth. It is the most highly mineralized and hardest tissue in the body. Dental enamel is acellular and has no physiological means of repair outside of the protective and remineralization potential provided by saliva. Enamel is comprised of highly organized hydroxyapatite crystals that form in a defined extracellular space, the contents of which are supplied and regulated by ameloblasts. The entire process is under genetic instruction. The genetic control of amelogenesis is poorly understood, but requires the activities of multiple components that are uniquely important for dental enamel formation. Amelogenesis imperfecta (AI) is a collective designation for the variety of inherited conditions displaying isolated enamel malformations, but the designation is also used to indicate the presence of an enamel phenotype in syndromes. Recently, genetic studies have demonstrated the importance of genes encoding enamel matrix proteins in the etiology of isolated AI. Here we review the essential elements of dental enamel formation and the results of genetic analyses that have identified disease-causing mutations in genes encoding enamel matrix proteins. In addition, we provide a fresh perspective on the roles matrix proteins play in catalyzing the biomineralization of dental enamel. Copyright 2007 S. Karger AG, Basel.

  8. Measurement of the efficacy of calcium silicate for the protection and repair of dental enamel.

    Science.gov (United States)

    Parker, Alexander S; Patel, Anisha N; Al Botros, Rehab; Snowden, Michael E; McKelvey, Kim; Unwin, Patrick R; Ashcroft, Alexander T; Carvell, Mel; Joiner, Andrew; Peruffo, Massimo

    2014-06-01

    To investigate the formation of hydroxyapatite (HAP) from calcium silicate and the deposition of calcium silicate onto sound and acid eroded enamel surfaces in order to investigate its repair and protective properties. Calcium silicate was mixed with phosphate buffer for seven days and the resulting solids analysed for crystalline phases by Raman spectroscopy. Deposition studies were conducted on bovine enamel surfaces. Acid etched regions were produced on the enamel surfaces using scanning electrochemical cell microscopy (SECCM) with acid filled pipettes and varying contact times. Following treatment with calcium silicate, the deposition was visualised with FE-SEM and etch pit volumes were measured by AFM. A second set of bovine enamel specimens were pre-treated with calcium silicate and fluoride, before acid exposure with the SECCM. The volumes of the resultant acid etched pits were measured using AFM and the intrinsic rate constant for calcium loss was calculated. Raman spectroscopy confirmed that HAP was formed from calcium silicate. Deposition studies demonstrated greater delivery of calcium silicate to acid eroded than sound enamel and that the volume of acid etched enamel pits was significantly reduced following one treatment (penamel was 0.092 ± 0.008 cm/s. This was significantly reduced, 0.056 ± 0.005 cm/s, for the calcium silicate treatments (penamel surfaces. Calcium silicate can provide significant protection of sound enamel from acid challenges. Calcium silicate is a material that has potential for a new approach to the repair of demineralised enamel and the protection of enamel from acid attacks, leading to significant dental hard tissue benefits. © 2014 Elsevier Ltd. All rights reserved.

  9. Near-surface structural examination of human tooth enamel subject to in vitro demineralization and remineralization

    Science.gov (United States)

    Gaines, Carmen Veronica

    The early stages of chemical tooth decay are governed by dynamic processes of demineralization and remineralization of dental enamel that initiates along the surface of the tooth. Conventional diagnostic techniques lack the spatial resolution required to analyze near-surface structural changes in enamel at the submicron level. In this study, slabs of highly-polished, decay-free human enamel were subjected to 0.12M EDTA and buffered lactic acid demineralizing agents and MI Paste(TM) and calcifying (0.1 ppm F) remineralizing treatments in vitro. Grazing incidence x-ray diffraction (GIXD), a technique typically used for thin film analysis, provided depth profiles of crystallinity changes in surface enamel with a resolution better than 100 nm. In conjunction with nanoindentation, a technique gaining acceptance as a means of examining the mechanical properties of sound enamel, these results were corroborated with well-established microscopy and Raman techniques to assess the nanohardness, morphologies and chemical nature of treated enamel. Interestingly, the average crystallite size of surface enamel along its c-axis dimension increased by nearly 40% after a 60 min EDTA treatment as detected by GIXD. This result was in direct contrast to the obvious surface degradation observed by microscopic and confocal Raman imaging. A decrease in nanohardness from 4.86 +/- 0.44 GPa to 0.28 +/- 0.10 GPa was observed. Collective results suggest that mineral dissolution characteristics evident on the micron scale may not be fully translated to the nanoscale in assessing the integrity of chemically-modified tooth enamel. While an intuitive decrease in enamel crystallinity was observed with buffered lactic acid-treated samples, demineralization was too slow to adequately quantify the enamel property changes seen. MI Paste(TM) treatment of EDTA-demineralized enamel showed preferential growth along the a-axis direction. Calcifying solution treatments of both demineralized sample types

  10. Quantitative comparison of 3 enamel-stripping devices in vitro: how precisely can we strip teeth?

    Science.gov (United States)

    Johner, Alexander Marc; Pandis, Nikolaos; Dudic, Alexander; Kiliaridis, Stavros

    2013-04-01

    In this in-vitro study, we aimed to investigate the predictability of the expected amount of stripping using 3 common stripping devices on premolars. One hundred eighty extracted premolars were mounted and aligned in silicone. Tooth mobility was tested with Periotest (Medizintechnik Gulden, Modautal, Germany) (8.3 ± 2.8 units). The selected methods for interproximal enamel reduction were hand-pulled strips (Horico, Hapf Ringleb & Company, Berlin, Germany), oscillating segmental disks (O-drive-OD 30; KaVo Dental, Biberach, Germany), and motor-driven abrasive strips (Orthofile; SDC Switzerland, Lugano-Grancia, Switzerland). With each device, the operator intended to strip 0.1, 0.2, 0.3, or 0.4 mm on the mesial side of 15 teeth. The teeth were scanned before and after stripping with a 3-dimensional laser scanner. Superposition and measurement of stripped enamel on the most mesial point of the tooth were conducted with Viewbox software (dHal Software, Kifissia, Greece). The Wilcoxon signed rank test and the Kruskal-Wallis test were applied; statistical significance was set at alpha ≤ 0.05. Large variations between the intended and the actual amounts of stripped enamel, and between stripping procedures, were observed. Significant differences were found at 0.1 mm of intended stripping (P ≤ 0.05) for the hand-pulled method and at 0.4 mm of intended stripping (P ≤ 0.001 to P = 0.05) for all methods. For all scenarios of enamel reduction, the actual amount of stripping was less than the predetermined and expected amount of stripping. The Kruskal-Wallis analysis showed no significant differences between the 3 methods. There were variations in the stripped amounts of enamel, and the stripping technique did not appear to be a significant predictor of the actual amount of enamel reduction. In most cases, actual stripping was less than the intended amount of enamel reduction. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights

  11. Bonding strategies for MIH-affected enamel and dentin.

    Science.gov (United States)

    Krämer, Norbert; Bui Khac, Ngoc-Han Nana; Lücker, Susanne; Stachniss, Vitus; Frankenberger, Roland

    2018-02-01

    Aim of the present study was to evaluate resin composite adhesion to dental hard tissues affected by molar incisor hypomineralisation (MIH). 94 freshly extracted human molars and incisors (53 suffering MIH) were used. 68 teeth (35 with MIH) were used for μ-TBS tests in enamel and dentin, 26 (18 with MIH) for qualitative evaluation. Specimens were bonded with Clearfil SE Bond, Scotchbond Universal, and OptiBond FL. For MIH affected enamel, additional OptiBond FL groups with NaOCl and NaOCl+Icon were investigated. Beside fractographic analysis, also qualitative evaluations were performed using SEM at different magnifications as well as histological sectioning. Highest μ-TBS values were recorded with dentin specimens (ANOVA, mod. LSD, p0.05). Pre-test failures did not occur in dentin specimens. Sound enamel specimens exhibited significantly higher μ-TBS values than MIH enamel (p0.05), however, it caused less pre-test failures (pMIH enamel is the limiting factor in adhesion to MIH teeth. MIH-affected dentin may be bonded conventionally. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  12. EFFECT OF SURFACE CONDTIONINGON BOND STRENGTH TO ENAMEL AND DENTIN

    Directory of Open Access Journals (Sweden)

    M MOUSAVINASAB

    2002-09-01

    Full Text Available Introduction. Compoglass is a trade mark of dental compomers and because of its partially resinus structure, surface conditioning of dental surfaces is needed for a better bonding process. In this study, the effect of enamel and dentin conditioning procedure on shear bond strength (SBS of compoglass to tooth surfaces was studied. Methods. four groups each one including 11 sound premolars were chosen and their surfaces were prepared as following groups: group1, unconitioned dentin; group 2, dentin conditioning with phosphoric acid 35%; group 3, dentin conditioning with polyacrylic acid 20% group 4, unconditioning enamel; group 5, enamel conditioning with phosphoric acid 35%; and group 6, enamel conditioning with polyacrylic acid 20%. Compoglass was bonded to prepared surfaces and after fixation of the samples in acrylic molds, all samples were tested under shear force of instron testing machine at a rate of 1 mm/min speed. Results. The mean SBS obtained in these 6 groups were 6.207, 8.057, 10.146, 25.939 and 11.827 mpa. the mode of fracture also studied using a streomicroscope. Statistical analysis of the results showed that the maximum SBS obtained in group 5 and the lowest SBS about 6.207 mpa obtained in group 1. Despite increase in SBS group 2 and 3, there was no statistical differncies between group 1, 2 and 3. Discussion. Based on results of this study, conditioning of enamel and dentin surface due to improve SBS is recommeneded.

  13. Hipoplasia Enamel Pada Penderita Penyakit Eksantema

    OpenAIRE

    Dewi saputri

    2008-01-01

    Hipoplasia enamel merupakan gangguan pada masa pemhentukan matriks organik yang menyebabkan gangguan struktur pada enamel sehingga secara klinis terlihat pada suatu bagian dari gigi tidak terbentuk enamel dan kadang-kadang sama sekali tidak terbentuk enamel, serta diikuti dengan perubahan warna pada gigi. Dikenal berbagai faktor penyebab hipoplasia enamel, salah satunya adalah penyakit eksantema yaitu menyebabkan infeksi pada bayi dan anak-anak. Gambaran histopatologis hipoplasia enamel adala...

  14. Mesial temporal lobe epilepsy - An overview of surgical techniques.

    Science.gov (United States)

    Muzumdar, Dattatraya; Patil, Manoj; Goel, Atul; Ravat, Sangeeta; Sawant, Nina; Shah, Urvashi

    2016-12-01

    Mesial temporal lobe epilepsy is one of the commonest indications for epilepsy surgery. Presurgical evaluation for drug resistant epilepsy and identification of appropriate candidates for surgery is essential for optimal seizure freedom. The anatomy of mesial temporal lobe is complex and needs to be understood in the context of the advanced imaging, ictal and interictal Video_EEG monitoring, neuropsychology and psychiatric considerations. The completeness of disconnection of epileptogenic neural networks is paramount and is correlated with the extent of resection of the mesial temporal structures. In the Indian subcontinent, a standard but extended anterior temporal lobectomy is a viable option in view of the diverse socioeconomic, cultural and pathological considerations. The maximum utilization of epilepsy surgery services in this region is also a challenge. There is a need for regional comprehensive epilepsy care teams in a tertiary care academic hospital to form centers of excellence catering to a large population. Copyright © 2016 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

  15. MR imaging findings of patients with mesial temporal sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Jung; Kim, Sun Yong; Suh, Jung Ho [School of Medicine, Ajou University, Suwon (Korea, Republic of)

    2000-06-01

    To evaluate the MR imaging findings of patients with mesial temporal sclerosis. We retrospectively reviewed the MR imaging findings of 116 patients diagnosed by MRI as suffering from mesial temporal sclerosis. In 18 of these, the condition was also histologically proven. Among the 116 patients, volume loss of the hippocampus was found in 95 (81.9%) and signal changes of the hippocampus in 53 (45.7%). Decreased signal intensity in the hippocampus on T1-weighted images was found in 13 (11.2%) and increased signal on T2-weighted images in 50 (43.1%). Signal abnormality in the hippocampus on both T1- and T2-weighted images was found in ten, and associated extrahippocampal abnormalities, as follows, in 20 (17.2%): atrophy of fornix (n=3D10), atrophy of the mammillary body (n=3D8), atrophy of the amygdala (n=3D10), atrophy or increased T2 signal intensity of the anterior thalamic nuclei (n=3D2), atrophy of the cingulate gyrus (n=3D2), atrophy or increased signal intensity of the anterior temporal lobe (n=3D8), and cerebral hemiatrophy (n=3D4). A high T2 signal and atrophy of the hippocampus are the most common and important MRI findings of mesial temporal sclerosis. Other abnormal findings, if any, which may be found in extrahippocampal structures such as the fornix, mammillary body and temporal lobe, should, however, also be carefully observed. (author)

  16. Microstructure of enamel.

    Science.gov (United States)

    Boyde, A

    1997-01-01

    Enamel is a composite material consisting of mineral and organic phases. The properties of the mineral phase are modulated dramatically by its division into microscopic crystals, cemented together by the organic matrix protein polymer. A good concept of the 3D orientations of the crystals derives from visualizing their growth perpendicular to the surface in which they develop, which is pitted by the secretory poles of the ameloblasts. The arrangement of the crystals is the cause of the discontinuities, known as the prism boundaries or junctions, in the otherwise continuous structure. These locations acquire a more concentrated organic matrix during maturation, and they are both crack stoppers and crack propagation tracks in the adult tissue. Any tendency of prisms to cleave may be reduced by their varicosities, which reflect daily variations in the rate of production; their cross-sectional shape; the non-parallelism of adjacent groups, which develops through translocation of groups of cells across the surface during development; and the support of any one microscopic tissue element by other tissue, including dentine, placed to resist an applied load. Incremental growth lines are preferential cleavage planes within the enamel. Failure patterns of enamel in normal and abnormal use can be explained by these parameters, with additional consideration of functional variation and fatigue.

  17. Active application of primer acid on acid-treated enamel: Influence on the bond effectiveness of self-etch adhesives systems.

    Science.gov (United States)

    Araújo, Cíntia Tereza Pimenta; Prieto, Lúcia Trazzi; Costa, Daiane Cristianismo; Bosso, Mariana Avalone; Coppini, Erick Kamiya; Dias, Carlos Tadeu Santos; Paulillo, Luis Alexandre Maffei Sartini

    2017-08-01

    Evaluate the composite-to-enamel bond after passive or active application of self-etching primer systems on polished or pre-etched enamel with phosphoric acid. Two self-etch adhesives systems (SEAS) were used: Clearfil SE Bond and Easy Bond. Third human molars were divided into 8 groups (N = 10). The crown of each tooth was sectioned into halves and the mesial/distal surfaces were used. The adhesives were actively or passively applied on enamel with or without prior phosphoric-acid etching. Resin composite cylinders were built after adhesive application. After stored in relative humidity for 24 hr/37°C the specimens were subjected to microshear test in universal testing a machine at a crosshead speed of 0.5 mm/minute. The results were analyzed with three-way ANOVA and the Tukey test. The enamel-etching pattern was evaluated under SEM. The 2-step SEAS system presented significantly higher adhesive bond strength means (47.37 MPa) than the 1-step (36.87 MPa). A poor enamel- etching pattern was observed in active mode showing irregular and short resin tags, however there was not compromised the bond strength. Active or passive application produced similar values of bond strength to enamel regardless of enamel pretreatment and type of SEAS. © 2017 Wiley Periodicals, Inc.

  18. Mechanism of Action of TiF4 on Dental Enamel Surface: SEM/EDX, KOH-Soluble F, and X-Ray Diffraction Analysis.

    Science.gov (United States)

    Comar, Lívia P; Souza, Beatriz M; Al-Ahj, Luana P; Martins, Jessica; Grizzo, Larissa T; Piasentim, Isabelle S; Rios, Daniela; Buzalaf, Marília Afonso Rabelo; Magalhães, Ana Carolina

    2017-10-12

    This in vitro study aimed to evaluate the action of TiF4 on sound and carious bovine and human enamel. Sound (S) and pre-demineralised (DE) bovine and human (primary and permanent) enamel samples were treated with TiF4 (pH 1.0) or NaF varnishes (pH 5.0), containing 0.95, 1.95, or 2.45% F for 12 h. The enamel surfaces were analysed using SEM-EDX (scanning electron microscopy/energy-dispersive X-ray spectroscopy) (n = 10, 5 S and 5 DE) and KOH-soluble fluoride was quantified (n = 20, 10 S and 10 DE). Hydroxyapatite powder produced by precipitation method was treated with the corresponding fluoride solutions for 1 min (n = 2). The formed compounds were detected using X-ray diffraction (XRD). All TiF4 varnishes produced a coating layer rich in Ti and F on all types of enamel surface, with micro-cracks in its extension. TiF4 (1.95 and 2.45% F) provided higher fluoride deposition than NaF, especially for bovine enamel (p enamel. The Ti content was higher for bovine and human primary enamel than human permanent enamel, with some differences between S and DE. The XRD analysis showed that TiF4 induced the formation of new compounds such as CaF2, TiO2, and Ti(HPO4)2·H2O. In conclusion, TiF4 (>0.95% F) interacts better, when compared to NaF, with bovine and human primary enamel than with human permanent enamel. TiF4 provoked higher F deposition compared to NaF. Carious enamel showed higher F uptake than sound enamel by TiF4 application, while Ti uptake was dependent on the enamel condition and origin. © 2017 S. Karger AG, Basel.

  19. Dental Enamel Development: Proteinases and Their Enamel Matrix Substrates

    Science.gov (United States)

    Bartlett, John D.

    2013-01-01

    This review focuses on recent discoveries and delves in detail about what is known about each of the proteins (amelogenin, ameloblastin, and enamelin) and proteinases (matrix metalloproteinase-20 and kallikrein-related peptidase-4) that are secreted into the enamel matrix. After an overview of enamel development, this review focuses on these enamel proteins by describing their nomenclature, tissue expression, functions, proteinase activation, and proteinase substrate specificity. These proteins and their respective null mice and human mutations are also evaluated to shed light on the mechanisms that cause nonsyndromic enamel malformations termed amelogenesis imperfecta. Pertinent controversies are addressed. For example, do any of these proteins have a critical function in addition to their role in enamel development? Does amelogenin initiate crystallite growth, does it inhibit crystallite growth in width and thickness, or does it do neither? Detailed examination of the null mouse literature provides unmistakable clues and/or answers to these questions, and this data is thoroughly analyzed. Striking conclusions from this analysis reveal that widely held paradigms of enamel formation are inadequate. The final section of this review weaves the recent data into a plausible new mechanism by which these enamel matrix proteins support and promote enamel development. PMID:24159389

  20. Bicarbonate Transport During Enamel Maturation.

    Science.gov (United States)

    Yin, Kaifeng; Paine, Michael L

    2017-11-01

    Amelogenesis (tooth enamel formation) is a biomineralization process consisting primarily of two stages (secretory stage and maturation stage) with unique features. During the secretory stage, the inner epithelium of the enamel organ (i.e., the ameloblast cells) synthesizes and secretes enamel matrix proteins (EMPs) into the enamel space. The protein-rich enamel matrix forms a highly organized architecture in a pH-neutral microenvironment. As amelogenesis transitions to maturation stage, EMPs are degraded and internalized by ameloblasts through endosomal-lysosomal pathways. Enamel crystallite formation is initiated early in the secretory stage, however, during maturation stage the more rapid deposition of calcium and phosphate into the enamel space results in a rapid expansion of crystallite length and mineral volume. During maturation-stage amelogenesis, the pH value of enamel varies considerably from slightly above neutral to acidic. Extracellular acid-base balance during enamel maturation is tightly controlled by ameloblast-mediated regulatory networks, which include significant synthesis and movement of bicarbonate ions from both the enamel papillary layer cells and ameloblasts. In this review we summarize the carbonic anhydrases and the carbonate transporters/exchangers involved in pH regulation in maturation-stage amelogenesis. Proteins that have been shown to be instrumental in this process include CA2, CA6, CFTR, AE2, NBCe1, SLC26A1/SAT1, SLC26A3/DRA, SLC26A4/PDS, SLC26A6/PAT1, and SLC26A7/SUT2. In addition, we discuss the association of miRNA regulation with bicarbonate transport in tooth enamel formation.

  1. Fluoride varnishes and enamel caries

    NARCIS (Netherlands)

    Bruyn, Hugo de

    1987-01-01

    Topical fluoride applications have the aim of increasing the fluoride uptake in enamel and consequently reducing caries. In the early ‘60s fluoride varnishes were introduced because they had a long contact period with the enamel which resulted in a higher fluoride uptake than from other topical

  2. Silicate enamel for alloyed steel

    International Nuclear Information System (INIS)

    Ket'ko, K.K.

    1976-01-01

    The use of silicate enamels in the metallurgical industry is discussed. Presented are the composition and the physico-chemical properties of the silicate enamel developed at the factory 'Krasnyj Oktyabr'. This enamel can be used in the working conditions both in the liquid and the solid state. In so doing the enamel is melted at 1250 to 1300 deg C, granulated and then reduced to a fraction of 0.3 to 0.5 mm. The greatest homogeneity is afforded by a granulated enamel. The trials have shown that the conversion of the test ingots melted under a layer of enamel leads to the smaller number of the ingots rejected for surface defect reasons and the lower metal consumption for slab cleaning. The cost of the silicate enamel is somewhat higher than that of synthetic slags but its application to the melting of stainless steels is still economically beneficial and technologically reasonable. Preliminary calculations only for steel EhI4IEh have revealed that the use of this enamel saves annually over 360000 roubles [ru

  3. Morphology and fracture of enamel.

    Science.gov (United States)

    Myoung, Sangwon; Lee, James; Constantino, Paul; Lucas, Peter; Chai, Herzl; Lawn, Brian

    2009-08-25

    This study examines the inter-relation between enamel morphology and crack resistance by sectioning extracted human molars after loading to fracture. Cracks appear to initiate from tufts, hypocalcified defects at the enamel-dentin junction, and grow longitudinally around the enamel coat to produce failure. Microindentation corner cracks placed next to the tufts in the sections deflect along the tuft interfaces and occasionally penetrate into the adjacent enamel. Although they constitute weak interfaces, the tufts are nevertheless filled with organic matter, and appear to be stabilized against easy extension by self-healing, as well as by mutual stress-shielding and decussation, accounting at least in part for the capacity of tooth enamel to survive high functional forces.

  4. Investigation of 16% carbamide-peroxide on the structure and properties and effect return enamel staining teeth whitening after their

    Directory of Open Access Journals (Sweden)

    Matvijenko Vladimir

    2015-01-01

    Full Text Available The most tooth whitening is a procedure that removes stains and various discolorations of tooth surface. Discoloration of teeth may be endogenous and exogenous nature. The aim of this study was to investigate the impact of bleaching combined with daily use of drinks that cause tooth discoloration. Evaluated the changes in surface structure of enamel, and changes in hardness after bleaching. Were 20 extracted teeth. The teeth are marked with longitudinal lines halves (medial vestibular and distal surfaces. Tretitana mesial half of the 16% carbamide peroxide, a distal was left as control. NDT device HL-400DL, duroskopskom method of enamel hardness was measured before treatment, after treatment and after remineralization. Olympus inverted microscope GX41 enamel structures were observed in the treated and control half of the tooth. After bleaching there is a difference compared to the untreated surface, that surface is bleached a few shades lighter, but after the use of coffee and soft drinks teeth back to the original dark color. Enamel microhardness after the treatment is somewhat small but not significant. With a magnification of 2000x and see the structural changes in enamel. Tooth whitening, but that the remineralization and the abstinence from prebojenih beverages and tobacco.

  5. The effect of additional enamel etching and a flowable composite to the interfacial integrity of Class II adhesive composite restorations.

    Science.gov (United States)

    Belli, S; Inokoshi, S; Ozer, F; Pereira, P N; Ogata, M; Tagami, J

    2001-01-01

    This in vitro study evaluated the interfacial integrity of Class II resin composite restorations. The influence of a flowable composite and additional enamel etching was also evaluated. Deep, saucer-shaped Class II cavities were prepared in the mesial and distal proximal surfaces of 25 extracted human molars and assigned to five treatment groups. The gingival margins were extended to approximately 1 mm above the CEJ in 40 cavities and below the CEJ in 10 cavities. The prepared cavities were then restored with a self-etching primer system (Clearfil Liner Bond II) and a hybrid resin composite (Clearfil AP-X), with and without a flowable composite (Protect Liner F) and additional enamel etching with 37% phosphoric acid gel (K-etchant). After finishing, polishing and thermocycling (4 and 60 degrees C, x300), the samples were longitudinally sectioned through the restorations and resin-tooth interfaces were observed directly under a laser scanning microscope. Statistical analysis indicated that the use of a flowable composite produced significantly more (p = 0.04) gap-free resin-dentin interfaces than teeth restored without the flowable composite. However, both flowable composite and enamel etching could not prevent gap formation at enamel-resin interfaces and crack formation on enamel walls.

  6. Mechanical characterization of enamel coated steel bars.

    Science.gov (United States)

    2012-12-01

    In this study, the corrosion process of enamel-coated deformed rebar completely immersed in 3.5 wt.% NaCl solution was evaluated : over a period of 84 days by EIS testing. Three types of enamel coating were investigated: pure enamel, 50/50 enamel coa...

  7. Effect of enamel organic matrix on the potential of Galla chinensis to promote the remineralization of initial enamel carious lesions in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Linglin; Zou Ling; Li Jiyao; Hao Yuqing; Xiao Liying; Zhou Xuedong; Li Wei, E-mail: leewei2000@sina.co, E-mail: zhll_sc@yahoo.c [State Key Laboratory of Oral Diseases, West China College of Stomatology, West China Hospital of Stomatology, Sichuan University, Chengdu (China)

    2009-06-15

    Galla chinensis, a natural traditional Chinese medicine with main composition of tannic acid and gallic acid, is formed when the Chinese sumac aphid Baker (Melaphis chinensis bell) parasitizes the levels of Rhus chinensis Mill. Galla chinensis has shown the potential to enhance the remineralization of initial enamel carious lesion, but the mechanism is still unknown. This study was to investigate whether the enamel organic matrix plays a significant role in the potential of Galla chinensis to promote the remineralization of initial enamel caries. Bovine sound enamel blocks and non-organic enamel blocks were demineralized and exposed to a 12 day pH cycling. During the pH cycling, 30 specimens with the enamel organic matrix were randomly divided into three groups, and treated with 1 g L{sup -1} NaF (group A), 4 g L{sup -1} Galla chinensis extract (group B1) or double deionized water (group C1). Twenty specimens without the enamel organic matrix were randomly divided into two groups, and treated with 4 g L{sup -1} Galla chinensis extract (group B2) or double deionized water (group C2). The integrated mineral loss and lesion depth of all the specimens were analysed by transverse microradiography. The integrated mineral loss and lesion depth of group B1 were less than those of groups B2, C1 and C2, and there were no statistical differences among groups B2, C1 and C2. In conclusion, Galla chinensis can enhance the remineralization of initial enamel carious lesion, and the enamel organic matrix plays a significant role in this potential of Galla chinensis.

  8. Determinants of brain metabolism changes in mesial temporal lobe epilepsy.

    Science.gov (United States)

    Chassoux, Francine; Artiges, Eric; Semah, Franck; Desarnaud, Serge; Laurent, Agathe; Landre, Elisabeth; Gervais, Philippe; Devaux, Bertrand; Helal, Ourkia Badia

    2016-06-01

    To determine the main factors influencing metabolic changes in mesial temporal lobe epilepsy (MTLE) due to hippocampal sclerosis (HS). We prospectively studied 114 patients with MTLE (62 female; 60 left HS; 15- to 56-year-olds) with (18) F-fluorodeoxyglucose-positron emission tomography and correlated the results with the side of HS, structural atrophy, electroclinical features, gender, age at onset, epilepsy duration, and seizure frequency. Imaging processing was performed using statistical parametric mapping. Ipsilateral hypometabolism involved temporal (mesial structures, pole, and lateral cortex) and extratemporal areas including the insula, frontal lobe, perisylvian regions, and thalamus, more extensively in right HS (RHS). A relative increase of metabolism (hypermetabolism) was found in the nonepileptic temporal lobe and in posterior areas bilaterally. Voxel-based morphometry detected unilateral hippocampus atrophy and gray matter concentration decrease in both frontal lobes, more extensively in left HS (LHS). Regardless of the structural alterations, the topography of hypometabolism correlated strongly with the extent of epileptic networks (mesial, anterior-mesiolateral, widespread mesiolateral, and bitemporal according to the ictal spread), which were larger in RHS. Notably, widespread perisylvian and bitemporal hypometabolism was found only in RHS. Mirror hypermetabolism was grossly proportional to the hypometabolic areas, coinciding partly with the default mode network. Gender-related effect was significant mainly in the contralateral frontal lobe, in which metabolism was higher in female patients. Epilepsy duration correlated with the contralateral temporal metabolism, positively in LHS and negatively in RHS. Opposite results were found with age at onset. High seizure frequency correlated negatively with the contralateral metabolism in LHS. Epileptic networks, as assessed by electroclinical correlations, appear to be the main determinant of

  9. Persistent Interictal Musical Hallucination in a Patient With Mesial Temporal Sclerosis-Related Epilepsy: First Case Report and Etiopathological Hypothesis.

    Science.gov (United States)

    Borelli, Paolo; Vedovello, Marcella; Braga, Massimiliano; Pederzoli, Massimo; Beretta, Sandro

    2016-12-01

    Musical hallucination is a disorder of complex sound processing of instrumental music, songs, choirs, chants, etc. The underlying pathologies include moderate to severe acquired hearing loss (the auditory equivalent of Charles Bonnet syndrome), psychiatric illnesses (depression, schizophrenia), drug intoxication (benzodiazepines, salicylate, pentoxifylline, propranolol), traumatic lesions along the acoustic pathways, and epilepsy. The hallucinations are most likely to begin late in life; 70% of patients are women. Musical hallucination has no known specific therapy. Treating the underlying cause is the most effective approach; neuroleptic and antidepressant medications have only rarely succeeded.Musical hallucination in epilepsy typically presents as simple partial seizures originating in the lateral temporal cortex. To our knowledge, no formal report of musical hallucination in the interictal state has been published before. In contrast, other interictal psychotic features are a relatively common complication, especially in patients with long-standing drug-resistant epilepsy.We describe a 62-year-old woman with a long history of mesial temporal lobe epilepsy whose musical hallucination was solely interictal. We speculate on the possible link between temporal epilepsy and her hallucination. We hypothesize that, as a result of her epileptic activity-induced damage, an imbalance developed between the excitatory and inhibitory projections connecting the mesial temporal cortex to the other auditory structures. These structures may have generated hyperactivity in the lateral temporal cortex through a "release" mechanism that eventually resulted in musical hallucination.

  10. Morphological, chemical and structural characterisation of deciduous enamel: SEM, EDS, XRD, FTIR and XPS analysis.

    Science.gov (United States)

    Zamudio-Ortega, C M; Contreras-Bulnes, R; Scougall-Vilchis, R J; Morales-Luckie, R A; Olea-Mejía, O F; Rodríguez-Vilchis, L E

    2014-09-01

    The purpose of this study was to characterise the enamel surface of sound deciduous teeth in terms of morphology, chemical composition, structure and crystalline phases. The enamel of 30 human deciduous teeth was examined by: Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), X-ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS). Chemical differences between incisors and canines were statistically evaluated using the Mann-Whitney U test (p ≤ 0.05). Three enamel patterns were observed by SEM: 'mostly smooth with some groves', 'abundant microporosities' and 'exposed prisms'. The average Ca/P molar ratios were 1.37 and 1.03 by EDS and XPS, respectively. The crystallite size determined by XRD was 210.82 ± 16.78 Å. The mean ratio between Ca bonded to phosphate and Ca bonded to hydroxyl was approximately 10:1. The enamel of sound deciduous teeth showed two main patterns: 'mostly smooth with some groves' and 'abundant microporosities'. 'Exposed prisms' was a secondary pattern. There were slight variations among the Ca/P molar ratios found by EDS and XPS, suggesting differences in the mineral content from the enamel surface to the interior. The crystalline phases found in enamel were hydroxyapatite and carbonate apatite, with major type B than type A carbonate incorporation.

  11. Three-dimensional primate molar enamel thickness.

    Science.gov (United States)

    Olejniczak, Anthony J; Tafforeau, Paul; Feeney, Robin N M; Martin, Lawrence B

    2008-02-01

    Molar enamel thickness has played an important role in the taxonomic, phylogenetic, and dietary assessments of fossil primate teeth for nearly 90 years. Despite the frequency with which enamel thickness is discussed in paleoanthropological discourse, methods used to attain information about enamel thickness are destructive and record information from only a single plane of section. Such semidestructive planar methods limit sample sizes and ignore dimensional data that may be culled from the entire length of a tooth. In light of recently developed techniques to investigate enamel thickness in 3D and the frequent use of enamel thickness in dietary and phylogenetic interpretations of living and fossil primates, the study presented here aims to produce and make available to other researchers a database of 3D enamel thickness measurements of primate molars (n=182 molars). The 3D enamel thickness measurements reported here generally agree with 2D studies. Hominoids show a broad range of relative enamel thicknesses, and cercopithecoids have relatively thicker enamel than ceboids, which in turn have relatively thicker enamel than strepsirrhine primates, on average. Past studies performed using 2D sections appear to have accurately diagnosed the 3D relative enamel thickness condition in great apes and humans: Gorilla has the relatively thinnest enamel, Pan has relatively thinner enamel than Pongo, and Homo has the relatively thickest enamel. Although the data set presented here has some taxonomic gaps, it may serve as a useful reference for researchers investigating enamel thickness in fossil taxa and studies of primate gnathic biology.

  12. Middle mesial canals in mandibular molars: incidence and related factors.

    Science.gov (United States)

    Nosrat, Ali; Deschenes, Raney J; Tordik, Patricia A; Hicks, M Lamar; Fouad, Ashraf F

    2015-01-01

    Although the internal anatomy of mandibular molars has been extensively studied, information about middle mesial (MM) canals is limited. The primary aim of this retrospective study was to evaluate the incidence of MM canals in mandibular first and second molars. The secondary aim was to correlate the incidence of MM canals with variables of molar type, sex, age, ethnicity, and presence of a second distal canal. All mature permanent first and second mandibular molars treated from August 2012 to May 2014 were included in the analysis. After completion of root canal instrumentation in all main canals, the clinician inspected the isthmus area of the mesial root using the dental operating microscope. If there was a catch point in this area with a file or explorer, the operator spent more time attempting to negotiate an MM canal. Seventy-five mandibular first and second molars were treated during the specified period. Fifteen (20%) teeth had negotiable MM canals. The incidence of MM canals was 32.1% in patients ≤ 20 years old, 23.8% in patients 21-40 years old, and 3.8% in patients > 40 years. Analysis of data revealed a significant difference in the distribution of MM canals among different age groups (P molar type, and presence of a second distal canal were not significant. The incidence of negotiable MM canals overall and their frequency of identification in younger patients were higher than in previous reports. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  13. Complications after mesial temporal lobe surgery via inferiortemporal gyrus approach.

    Science.gov (United States)

    Vale, Fernando L; Reintjes, Stephen; Garcia, Hermes G

    2013-06-01

    The purpose of this study was to identify the complications associated with the inferior temporal gyrus approach to anterior mesial temporal lobe resection for temporal lobe epilepsy. This retrospective study examined complications experienced by 483 patients during the 3 months after surgery. All surgeries were performed during 1998-2012 by the senior author (F.L.V.). A total of 13 complications (2.7%) were reported. Complications were 8 delayed subdural hematomas (1.6%), 2 superficial wound infections (0.4%), 1 delayed intracranial hemorrhage (0.2%), 1 small lacunar stroke (0.2%), and 1 transient frontalis nerve palsy (0.2%). Three patients with subdural hematoma (0.6%) required readmission and surgical intervention. One patient (0.2%) with delayed intracranial hemorrhage required readmission to the neuroscience intensive care unit for observation. No deaths or severe neurological impairments were reported. Among the 8 patients with subdural hematoma, 7 were older than 40 years (87.5%); however, this finding was not statistically significant (p = 0.198). The inferior temporal gyrus approach to mesial temporal lobe resection is a safe and effective method for treating temporal lobe epilepsy. Morbidity and mortality rates associated with this procedure are lower than those associated with other neurosurgical procedures. The finding that surgical complications seem to be more common among older patients emphasizes the need for early surgical referral of patients with medically refractory epilepsy.

  14. Studies of direct electroinsulating enamels

    International Nuclear Information System (INIS)

    Siwulski, S.; Gruszka, B.; Nocun, M.

    1998-01-01

    The results of studies on the influence of chemical composition of direct electroinsulating enamel on its properties were presented. The influence of alkaline Li 2 O, Na 2 O, K 2 O and adhesion promoting oxides CoO, NiO, CuO, MoO 3 on the frits properties were estimated. The characteristic temperature T g and T m as well as flowability were measured. The dielectric properties of frits and prepared enamels were also measured. Enamel substrates were prepared and tested for application in thick hybrid circuit technology. (author)

  15. Sound algorithms

    OpenAIRE

    De Götzen , Amalia; Mion , Luca; Tache , Olivier

    2007-01-01

    International audience; We call sound algorithms the categories of algorithms that deal with digital sound signal. Sound algorithms appeared in the very infancy of computer. Sound algorithms present strong specificities that are the consequence of two dual considerations: the properties of the digital sound signal itself and its uses, and the properties of auditory perception.

  16. Mandibular second molar with 3 mesial canals and a radix paramolaris

    Directory of Open Access Journals (Sweden)

    N Ragavendran

    2014-01-01

    Full Text Available Mandibular first molar commonly has two roots, the mesial and the distal root. Surprisingly in some mandibular first molar has an unusual extra third root in between mesial and distal root. This extra root is the most commonly seen in lingual side and is called as radix entomolaris. If this extra root is seen on the buccal side, it is termed as radix paramolaris (RP, which is a very rare phenomenon. Recently, various case report studies has shown the presence of third canal in the mesial and distal roots of mandibular molars. They are named as middle mesial and middle distal canal, respectively. Here, we present a case report of mandibular second molar showing three canals in the mesial root and a RP.

  17. Influence of Different Etching Modes on Bond Strength to Enamel using Universal Adhesive Systems.

    Science.gov (United States)

    Diniz, Ana Cs; Bandeca, Matheus C; Pinheiro, Larissa M; Dos Santosh Almeida, Lauber J; Torres, Carlos Rg; Borges, Alvaro H; Pinto, Shelon Cs; Tonetto, Mateus R; De Jesus Tavarez, Rudys R; Firoozmand, Leily M

    2016-10-01

    The adhesive systems and the techniques currently used are designed to provide a more effective adhesion with reduction of the protocol application. The objective of this study was to evaluate the bond strength of universal adhesive systems on enamel in different etching modes (self-etch and total etch). The mesial and distal halves of 52 bovine incisors, healthy, freshly extracted, were used and divided into seven experimental groups (n = 13). The enamel was treated in accordance with the following experimental conditions: FUE-Universal System - Futurabond U (VOCO) with etching; FUWE - Futurabond U (VOCO) without etching; SB-Total Etch System - Single Bond 2 (3M); SBUE-Universal System - Single Bond Universal (3M ESPE) with etching; SBUWE - Single Bond Universal (3M ESPE) without etching; CLE-Self-etch System - Clearfil SE Bond (Kuraray) was applied with etching; CLWE - Clearfil SE Bond (Kuraray) without etching. The specimens were made using the composite spectrum TPH (Dentsply) and stored in distilled water (37 ± 1°C) for 1 month. The microshear test was performed using the universal testing machine EMIC DL 2000 with the crosshead speed of 0.5 mm/minute. The bond strength values were analyzed using statistical tests (Kruskal-Wallis test and Mann-Whitney test) with Bonferroni correction. There was no statistically significant difference between groups (p adhesive interface revealed that most failures occurred between the interface composite resin and adhesive. The universal adhesive system used in dental enamel varies according to the trademark, and the previous enamel etching for universal systems and the self-etch both induced greater bond strength values. Selective enamel etching prior to the application of a universal adhesive system is a relevant strategy for better performance bonding.

  18. AFM analysis of bleaching effects on dental enamel microtopography

    International Nuclear Information System (INIS)

    Pedreira de Freitas, Ana Carolina; Cardoso Espejo, Luciana; Brossi Botta, Sergio; Sa Teixeira, Fernanda de; Cerqueira, Luz Maria Aparecida A.; Garone-Netto, Narciso; Bona Matos, Adriana; Barbosa da Silveira Salvadori, Maria Cecilia

    2010-01-01

    The purpose of this in vitro study was to test a new methodology to evaluate the effects of 35% hydrogen peroxide agent on the microtopography of sound enamel using an atomic force microscope (AFM). The buccal sound surfaces of three extracted human lower incisors were used, without polishing the surfaces to maintain them with natural morphology. These unpolished surfaces were subjected to bleaching procedure with 35% hydrogen peroxide that consisted of 4 applications of the bleaching agent on enamel surfaces for 10 min each application. Surface images were obtained in a 15 μm x 15 μm area using an AFM. The roughness (Ra and RMS) and the power spectral density (PSD) were obtained before and after the bleaching treatment. As results we could inquire that the PSD analyses were very suitable to identifying the morphological changes on the surfaces, while the Ra and RMS parameters were insufficient to represent the morphological alterations promoted by bleaching procedure on enamel. The morphological wavelength in the range of visible light spectrum (380-750 nm) was analyzed, showing a considerable increase of the PSD with the bleaching treatment.

  19. AFM analysis of bleaching effects on dental enamel microtopography

    Energy Technology Data Exchange (ETDEWEB)

    Pedreira de Freitas, Ana Carolina, E-mail: anacarolfreitas@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Cardoso Espejo, Luciana, E-mail: luespejo@hotmail.com [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Brossi Botta, Sergio, E-mail: sbbotta@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Sa Teixeira, Fernanda de, E-mail: nandast@if.usp.br [Laboratorio de Filmes Finos, Instituto de Fisica da Universidade de Sao Paulo, Rua do Matao, Travessa R, 187 - Cidade Universitaria, CEP 05314-970, Sao Paulo (Brazil); Cerqueira, Luz Maria Aparecida A., E-mail: maacluz@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Garone-Netto, Narciso, E-mail: ngarone@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Bona Matos, Adriana, E-mail: bona@usp.br [Departamento de Dentistica, Faculdade de Odontologia da Universidade de Sao Paulo, Av. Prof. Lineu Prestes, 2227 - Cidade Universitaria, CEP 05508-000, Sao Paulo (Brazil); Barbosa da Silveira Salvadori, Maria Cecilia, E-mail: mcsalva@if.usp.br [Laboratorio de Filmes Finos, Instituto de Fisica da Universidade de Sao Paulo, Rua do Matao, Travessa R, 187 - Cidade Universitaria, CEP 05314-970, Sao Paulo (Brazil)

    2010-02-15

    The purpose of this in vitro study was to test a new methodology to evaluate the effects of 35% hydrogen peroxide agent on the microtopography of sound enamel using an atomic force microscope (AFM). The buccal sound surfaces of three extracted human lower incisors were used, without polishing the surfaces to maintain them with natural morphology. These unpolished surfaces were subjected to bleaching procedure with 35% hydrogen peroxide that consisted of 4 applications of the bleaching agent on enamel surfaces for 10 min each application. Surface images were obtained in a 15 {mu}m x 15 {mu}m area using an AFM. The roughness (Ra and RMS) and the power spectral density (PSD) were obtained before and after the bleaching treatment. As results we could inquire that the PSD analyses were very suitable to identifying the morphological changes on the surfaces, while the Ra and RMS parameters were insufficient to represent the morphological alterations promoted by bleaching procedure on enamel. The morphological wavelength in the range of visible light spectrum (380-750 nm) was analyzed, showing a considerable increase of the PSD with the bleaching treatment.

  20. An association of external and internal enamel pearls.

    OpenAIRE

    Mahajan S; Charan C

    2005-01-01

    We report a rare case of an association of external enamel pearl with internal enamel pearl on the root of a molar. To the best of our knowledge, association of external and internal enamel pearls has not been previously reported. We discussed the histogenesis of enamel pearls and proposed that internal enamel pearl formation may be a continuation of formation of external enamel pearl.

  1. Relationships between birefringence and mineral content in artificial caries lesions of enamel.

    NARCIS (Netherlands)

    Theuns, H.M.; Shellis, R.P.; Groeneveld, A.; Dijk, J.W. van; Poole, D.F.

    1993-01-01

    The microradiographic mineral content and birefringence in water and Thoulet's solution were measured at selected points in sections of caries-like lesions. Birefringence was not related to mineral content in sound superficial enamel immersed in Thoulet's solution or in the lesion body immersed in

  2. Atypical febrile seizures, mesial temporal lobe epilepsy, and dual pathology.

    Science.gov (United States)

    Sanon, Nathalie T; Desgent, Sébastien; Carmant, Lionel

    2012-01-01

    Febrile seizures occurring in the neonatal period, especially when prolonged, are thought to be involved in the later development of mesial temporal lobe epilepsy (mTLE) in children. The presence of an often undetected, underlying cortical malformation has also been reported to be implicated in the epileptogenesis process following febrile seizures. This paper highlights some of the various animal models of febrile seizures and of cortical malformation and portrays a two-hit model that efficiently mimics these two insults and leads to spontaneous recurrent seizures in adult rats. Potential mechanisms are further proposed to explain how these two insults may each, or together, contribute to network hyperexcitability and epileptogenesis. Finally the clinical relevance of the two-hit model is briefly discussed in light of a therapeutic and preventive approach to mTLE.

  3. Mesial temporal lobe epilepsy diminishes functional connectivity during emotion perception.

    Science.gov (United States)

    Steiger, Bettina K; Muller, Angela M; Spirig, Esther; Toller, Gianina; Jokeit, Hennric

    2017-08-01

    Unilateral mesial temporal lobe epilepsy (MTLE) has been associated with impaired recognition of emotional facial expressions. Correspondingly, imaging studies showed decreased activity of the amygdala and cortical face processing regions in response to emotional faces. However, functional connectivity among regions involved in emotion perception has not been studied so far. To address this, we examined intrinsic functional connectivity (FC) modulated by the perception of dynamic fearful faces among the amygdala and limbic, frontal, temporal and brainstem regions. Regions of interest were identified in an activation analysis by presenting a block-design with dynamic fearful faces and dynamic landscapes to 15 healthy individuals. This led to 10 predominately right-hemispheric regions. Functional connectivity between these regions during the perception of fearful faces was examined in drug-refractory patients with left- (n=16) or right-sided (n=17) MTLE, epilepsy patients with extratemporal seizure onset (n=15) and a second group of 15 healthy controls. Healthy controls showed a widespread functional network modulated by the perception of fearful faces that encompassed bilateral amygdalae, limbic, cortical, subcortical and brainstem regions. In patients with left MTLE, a downsized network of frontal and temporal regions centered on the right amygdala was present. Patients with right MTLE showed almost no significant functional connectivity. A maintained network in the epilepsy control group indicates that findings in mesial temporal lobe epilepsy could not be explained by clinical factors such as seizures and antiepileptic medication. Functional networks underlying facial emotion perception are considerably changed in left and right MTLE. Alterations are present for both hemispheres in either MTLE group, but are more pronounced in right MTLE. Disruption of the functional network architecture possibly contributes to deficits in facial emotion recognition frequently

  4. Effects of bleaching agents on human enamel light reflectance.

    Science.gov (United States)

    Markovic, Ljubisa; Fotouhi, Kasra; Lorenz, Heribert; Jordan, Rainer A; Gaengler, Peter; Zimmer, Stefan

    2010-01-01

    Tooth whitening has been associated with splitting-up chromogenic molecules by hydrogen peroxides. Though micromorphological alterations are well documented, little is known about optical changes as a function of shifting in wavelengths. Therefore, the aim of the current study was to measure reflectance changes after bleaching in vitro by using a spectrometer. Forty-eight enamel slabs (diameter = 5 mm) were prepared from the sound enamel of extracted human teeth that were: 1) fully impacted, 2) from juveniles ages 10 to 16 years, 3) from adults 35 to 45 years of age and 4) from seniors older than age 65. In all specimens, the baseline total reflectance measurement was performed with a computer-assisted spectrometer (Ocean Optics, Dunedin, FL, USA) within wavelengths (wl) from 430 nm to 800 nm. Four enamel samples of each age group were exposed to either 10% or 15% carbamide peroxide (Illuminé Home, Dentsply, Konstanz, Germany) or 35% hydrogen peroxide (Pola Office, SDI Limited, Victoria, Australia). After surface treatment, all slabs underwent total reflectance measurement again. Statistical analysis was calculated at wl 450, 500 and 750 nm using the Student's paired t-test and one-way variance analysis. Total reflectance significantly increased after bleaching at all enamel maturation stages, irrespective of the bleaching agent concentration, for wl 450 nm (blue) and 500 nm (green) with penamel from adults and seniors (pwhitening of the dental enamel works at different maturation stages, even in impacted teeth. This effect is irrespective of the bleaching protocol used and the bleaching agent concentration.

  5. Verbal memory after temporal lobe epilepsy surgery in children: Do only mesial structures matter?

    Science.gov (United States)

    Law, Nicole; Benifla, Mony; Rutka, James; Smith, Mary Lou

    2017-02-01

    Previous findings have been mixed regarding verbal memory outcome after left temporal lobectomy in children, and there are few studies comparing verbal memory change after lateral versus mesial temporal lobe resections. We compared verbal memory outcome associated with sparing or including the mesial structures in children who underwent left or right temporal lobe resection. We also investigated predictors of postsurgical verbal memory change. We retrospectively assessed verbal memory change approximately 1 year after unilateral temporal lobe epilepsy surgery using a list learning task. Participants included 23 children who underwent temporal lobe surgery with sparing of the mesial structures (13 left), and 40 children who had a temporal lobectomy that included resection of mesial structures (22 left). Children who underwent resection from the left lateral and mesial temporal lobe were the only group to show decline in verbal memory. Furthermore, when we considered language representation in the left temporal resection group, patients with left language representation and spared mesial structures showed essentially no change in verbal memory from preoperative to follow-up, whereas those with left language representation and excised mesial structures showed a decline. Postoperative seizure status had no effect on verbal memory change in children after left temporal lobe surgery. Finally, we found that patients with intact preoperative verbal memory experienced a significant decline compared to those with below average preoperative verbal memory. Our findings provide evidence of significant risk factors for verbal memory decline in children, specific to left mesial temporal lobe epilepsy. Children who undergo left temporal lobe surgery that includes mesial structures may be most vulnerable for verbal memory decline, especially when language representation is localized to the left hemisphere and when preoperative verbal memory is intact. Wiley Periodicals, Inc.

  6. Dental Enamel Defects and Celiac Disease

    Science.gov (United States)

    ... Digestive System & How it Works Zollinger-Ellison Syndrome Dental Enamel Defects and Celiac Disease Celiac disease manifestations ... affecting any organ or body system. One manifestation—dental enamel defects—can help dentists and other health ...

  7. Properties of hot rolled steels for enamelling

    International Nuclear Information System (INIS)

    Gavrilovski, Dragica; Gavrilovski, Milorad

    2003-01-01

    The results of an investigation of the structure and properties of experimental produced hot rolled steels suitable for enamelling are presented in the paper. Hot rolled steels for enamelling represent a special group of the steels for conventional enamelling. Their quality has to be adapted to the method and conditions of enamelling. Therefore, these steels should meet some specific requirements. In addition to usual investigation of the chemical composition and mechanical properties, microstructure and quality of the steel surface also were investigated. The basic aim was to examine steels capability for enamelling, i. e. steels resistance to the fish scales phenomena, by trial enamelling, as well as quality of the steel - enamel contact surface, to evaluate the binding. Also, the changes of the mechanical properties, especially the yield point, during thermal treatment, as a very specific requirement, were investigated, by simplified method. Good results were obtained confirming the steels capability for enamelling. (Original)

  8. The fracture behaviour of dental enamel

    OpenAIRE

    Bechtle, Sabine; Habelitz, Stefan; Klocke, Arndt; Fett, Theo; Schneider, Gerold A.

    2009-01-01

    Abstract Enamel is the hardest tissue in the human body covering the crowns of teeth. Whereas the underlying dental material dentin is very well characterised in terms of mechanical and fracture properties, available data for enamel are quite limited and are apart from the most recent investigation mainly based on indentation studies. Within the current study, stable crack-growth experiments in bovine enamel have been performed, to measure fracture resistance curves for enamel. Single edge...

  9. Evaluation of a 6% hydrogen peroxide tooth-whitening gel on enamel microhardness after extended use.

    Science.gov (United States)

    Toteda, Mariarosaria; Philpotts, Carole J; Cox, Trevor F; Joiner, Andrew

    2008-11-01

    To evaluate the effects of a 6% hydrogen peroxide tooth whitener, Xtra White, on sound human enamel microhardness in vitro after an extended and exaggerated simulated 8 weeks of product use. Polished human enamel specimens were prepared and baseline microhardness and color measurements determined. The enamel specimens were exposed to a fluoride-containing toothpaste for 30 seconds and then exposed to water, Xtra White, a control carbopol gel containing no hydrogen peroxide, or a carbonated beverage (each group, n = 8) for 20 minutes. Specimens were exposed to whole saliva at all other times. In order to simulate 8 weeks of extended product use, quadruple the length of the manufacturer's instructions, 112 treatments, were conducted. Microhardness measurements were taken after 2, 4, 6, and 8 weeks of simulated treatments, and color was measured after 2 and 8 weeks. The Xtra White-treated specimens showed a statistically significant (P enamel microhardness between baseline and all treatment times for XW and water groups. Xtra White does not have any deleterious effects on sound human enamel microhardness after an extended and exaggerated simulated 8 weeks of product use.

  10. Spectrally enhanced imaging of occlusal surfaces and artificial shallow enamel erosions with a scanning fiber endoscope

    Science.gov (United States)

    Zhang, Liang; Nelson, Leonard Y.; Seibel, Eric J.

    2012-07-01

    An ultrathin scanning fiber endoscope, originally developed for cancer diagnosis, was used to image dental occlusal surfaces as well as shallow artificially induced enamel erosions from human extracted teeth (n=40). Enhanced image resolution of occlusal surfaces was obtained using a short-wavelength 405-nm illumination laser. In addition, artificial erosions of varying depths were also imaged with 405-, 404-, 532-, and 635-nm illumination lasers. Laser-induced autofluorescence images of the teeth using 405-nm illumination were also obtained. Contrast between sound and eroded enamel was quantitatively computed for each imaging modality. For shallow erosions, the image contrast with respect to sound enamel was greatest for the 405-nm reflected image. It was also determined that the increased contrast was in large part due to volume scattering with a smaller component from surface scattering. Furthermore, images obtained with a shallow penetration depth illumination laser (405 nm) provided the greatest detail of surface enamel topography since the reflected light does not contain contributions from light reflected from greater depths within the enamel tissue. Multilayered Monte Carlo simulations were also performed to confirm the experimental results.

  11. The development of enamel tubules during the formation of enamel in the marsupial Monodelphis domestica.

    OpenAIRE

    Sasagawa, I; Ferguson, M W

    1991-01-01

    In Monodelphis domestica, although both processes from odontoblasts and projections from ameloblasts were found in developing enamel, the majority of the contents of enamel tubules were probably processes that originated from odontoblasts. Processes from odontoblasts penetrating into enamel touched part of the ameloblasts in the stage of enamel formation. No specialised cell junctions were seen at the adherence between the two. There were no enamel tubules in the aprismatic and pseudoprismati...

  12. Transenamel and transdentinal penetration of hydrogen peroxide applied to cracked or microabrasioned enamel.

    Science.gov (United States)

    Briso, A L F; Lima, A P B; Gonçalves, R S; Gallinari, M O; dos Santos, P H

    2014-01-01

    The present study evaluated transenamel and transdentinal penetration of hydrogen peroxide during tooth whitening recognized in altered enamel by the presence of cracks or microabrasion. We used 72 experimental units (n=20) obtained from bovine incisors: GI-sound enamel; GII-teeth showing visible enamel cracks (4 mm to 5.7 mm in length); and GIII-microabrasioned enamel. The 12 remaining specimens were used to analyze the enamel surface morphology using scanning electron microscopy. The specimens were cylindrical and 5.7 mm in diameter and 3.5 mm thick. A product based on 35% hydrogen peroxide was used for bleaching, following the manufacturer's recommendations for use. To quantify the H2O2 penetration, the specimens were placed in artificial pulp chambers containing an acetate buffer solution. After bleaching, the solution was collected and adequately proportioned with leucocrystal violet, peroxidase enzyme, and deionized water. The resulting solution was evaluated using ultraviolet visible reflectance spectrophotometer equipment. The data were analyzed by analysis of variance (ANOVA) and Fisher's PLSD at a significance level of 0.05, and significant differences in the penetration of peroxide in different substrate conditions were observed (penamel was microabraded showed intermediate values when compared to the control group. Microabrasion and the presence of cracks in the enamel make this substrate more susceptible to penetration of hydrogen peroxide during in-office whitening.

  13. Enamel renal syndrome: A rare case report

    Directory of Open Access Journals (Sweden)

    S V Kala Vani

    2012-01-01

    Full Text Available Enamel renal syndrome is a very rare disorder associating amelogenesis imperfecta with nephrocalcinosis. It is known by various synonyms such as amelogenesis imperfecta nephrocalcinosis syndrome, MacGibbon syndrome, Lubinsky syndrome, and Lubinsky-MacGibbon syndrome. It is characterized by enamel agenesis and medullary nephrocalcinosis. This paper describes enamel renal syndrome in a female patient born in a consanguineous family.

  14. Foley Sounds vs Real Sounds

    DEFF Research Database (Denmark)

    Trento, Stefano; Götzen, Amalia De

    2011-01-01

    This paper is an initial attempt to study the world of sound effects for motion pictures, also known as Foley sounds. Throughout several audio and audio-video tests we have compared both Foley and real sounds originated by an identical action. The main purpose was to evaluate if sound effects...

  15. PIXE analysis of caries related trace elements in tooth enamel

    International Nuclear Information System (INIS)

    Annegarn, H.J.; Jodaikin, A.; Cleaton-Jones, P.E.; Sellschop, J.P.F.; Madiba, C.C.P.; Bibby, D.; University of the Witwatersrand, Johannesburg

    1981-01-01

    PIXE analysis has been applied to a set of twenty human teeth to determine trace element concentration in enamel from areas suceptible to dental caries (mesial and distal contact points) and in areas less susceptible to the disease (buccal surface), with the aim of determining the possible roles of trace elements in the carious process. The samples were caries-free anterior incisors extracted for periodontal reasons from subjects 10-30 years of age. Prior to extraction of the sample teeth, a detailed dental history and examination was carried out in each individual. PIXE analysis, using a 3 MeV proton beam of 1 mm diameter, allowed the determination of Ca, Mn, Fe, Cu, Zn, Sr and Pb above detection limits. As demonstrated in this work, the enhanced sensitivity of PIXE analysis over electron microprobe analysis, and capability of localised surface analysis compared with the pooled samples require for neutron activation analysis, makes it a powerful and useful technique in dental analysis. (orig.)

  16. PIXE analysis of caries related trace elements in tooth enamel

    Energy Technology Data Exchange (ETDEWEB)

    Annegarn, H J; Jodaikin, A; Cleaton-Jones, P E; Sellschop, J P.F.; Madiba, C C.P.; Bibby, D [University of the Witwatersrand, Johannesburg (South Africa). Nuclear Physics Research Unit; University of the Witwatersrand, Johannesburg (South Africa). Dental Research Unit)

    1981-03-01

    PIXE analysis has been applied to a set of twenty human teeth to determine trace element concentration in enamel from areas suceptible to dental caries (mesial and distal contact points) and in areas less susceptible to the disease (buccal surface), with the aim of determining the possible roles of trace elements in the carious process. The samples were caries-free anterior incisors extracted for periodontal reasons from subjects 10-30 years of age. Prior to extraction of the sample teeth, a detailed dental history and examination was carried out in each individual. PIXE analysis, using a 3 MeV proton beam of 1 mm diameter, allowed the determination of Ca, Mn, Fe, Cu, Zn, Sr and Pb above detection limits. As demonstrated in this work, the enhanced sensitivity of PIXE analysis over electron microprobe analysis, and capability of localised surface analysis compared with the pooled samples require for neutron activation analysis, makes it a powerful and useful technique in dental analysis.

  17. A mandibular third molar with three mesial roots: a case report.

    Science.gov (United States)

    Plotino, Gianluca

    2008-02-01

    Although its most common configuration is 2 roots and 3 root canals, mandibular molars might have many different combinations. A case of unusual root canal morphology is presented to demonstrate anatomic variations in mandibular molars. Endodontic therapy was performed in a mandibular third molar with 3 separate mesial roots. The appearance of the pulp chamber floor revealed 4 separate canal orifices. Radiographically the 4 root canals ended in their own distinct foramen. Many reports deal with 3 orifices or 3 independent canals in the mesial root, but none described 3 mesial canals in 3 separate mesial roots, indicating a rare anatomic configuration. This report points out the importance of looking for additional canals and unusual canal morphology, because knowledge of their existence might occasionally enable clinicians to treat a case successfully that otherwise might have ended in failure.

  18. Retrospective biodosimetry with small tooth enamel samples using K-Band and X-Band

    International Nuclear Information System (INIS)

    Gomez, Jorge A.; Kinoshita, Angela; Leonor, Sergio J.; Belmonte, Gustavo C.; Baffa, Oswaldo

    2011-01-01

    In an attempt to make the in vitro electron spin resonance (ESR) retrospective dosimetry of the tooth enamel a lesser invasive method, experiments using X-Band and K-Band were performed, aiming to determine conditions that could be used in cases of accidental exposures. First, a small prism from the enamel was removed and ground with an agate mortar and pestle until particles reach a diameter of approximately less than 0.5 mm. This enamel extraction process resulted in lower signal artifact compared with the direct enamel extraction performed with a diamond burr abrasion. The manual grinding of the enamel does not lead to any induced ESR signal artifact, whereas the use of a diamond burr at low speed produces a signal artifact equivalent to the dosimetric signal induced by a dose of 500 mGy of gamma irradiation. A mass of 25 mg of enamel was removed from a sound molar tooth previously irradiated in vitro with a dose of 100 mGy. This amount of enamel was enough to detect the dosimetric signal in a standard X-Band spectrometer. However using a K-Band spectrometer, samples mass between 5 and 10 mg were sufficient to obtain the same sensitivity. An overall evaluation of the uncertainties involved in the process in this and other dosimetric assessments performed at our laboratory indicates that it is possible at K-Band to estimate a 100 mGy dose with 25% accuracy. In addition, the use of K-Band also presented higher sensitivity and allowed the use of smaller sample mass in comparison with X-Band. Finally, the restoration process performed on a tooth after extraction of the 25 mg of enamel is described. This was conducted by dental treatment using photopolymerizable resin which enabled complete recovery of the tooth from the functional and aesthetic viewpoint showing that this procedure can be minimally invasive.

  19. Retrospective biodosimetry with small tooth enamel samples using K-Band and X-Band

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Jorge A. [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Kinoshita, Angela [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Universidade Sagrado Coracao - USC, 17011-160 Bauru, Sao Paulo (Brazil); Leonor, Sergio J. [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Belmonte, Gustavo C. [Universidade Sagrado Coracao - USC, 17011-160 Bauru, Sao Paulo (Brazil); Baffa, Oswaldo, E-mail: baffa@usp.br [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

    2011-09-15

    In an attempt to make the in vitro electron spin resonance (ESR) retrospective dosimetry of the tooth enamel a lesser invasive method, experiments using X-Band and K-Band were performed, aiming to determine conditions that could be used in cases of accidental exposures. First, a small prism from the enamel was removed and ground with an agate mortar and pestle until particles reach a diameter of approximately less than 0.5 mm. This enamel extraction process resulted in lower signal artifact compared with the direct enamel extraction performed with a diamond burr abrasion. The manual grinding of the enamel does not lead to any induced ESR signal artifact, whereas the use of a diamond burr at low speed produces a signal artifact equivalent to the dosimetric signal induced by a dose of 500 mGy of gamma irradiation. A mass of 25 mg of enamel was removed from a sound molar tooth previously irradiated in vitro with a dose of 100 mGy. This amount of enamel was enough to detect the dosimetric signal in a standard X-Band spectrometer. However using a K-Band spectrometer, samples mass between 5 and 10 mg were sufficient to obtain the same sensitivity. An overall evaluation of the uncertainties involved in the process in this and other dosimetric assessments performed at our laboratory indicates that it is possible at K-Band to estimate a 100 mGy dose with 25% accuracy. In addition, the use of K-Band also presented higher sensitivity and allowed the use of smaller sample mass in comparison with X-Band. Finally, the restoration process performed on a tooth after extraction of the 25 mg of enamel is described. This was conducted by dental treatment using photopolymerizable resin which enabled complete recovery of the tooth from the functional and aesthetic viewpoint showing that this procedure can be minimally invasive.

  20. Episodic and semantic memory in children with mesial temporal sclerosis.

    Science.gov (United States)

    Rzezak, Patricia; Guimarães, Catarina; Fuentes, Daniel; Guerreiro, Marilisa M; Valente, Kette Dualibi Ramos

    2011-07-01

    The aim of this study was to analyze semantic and episodic memory deficits in children with mesial temporal sclerosis (MTS) and their correlation with clinical epilepsy variables. For this purpose, 19 consecutive children and adolescents with MTS (8 to 16 years old) were evaluated and their performance on five episodic memory tests (short- and long-term memory and learning) and four semantic memory tests was compared with that of 28 healthy volunteers. Patients performed worse on tests of immediate and delayed verbal episodic memory, visual episodic memory, verbal and visual learning, mental scanning for semantic clues, object naming, word definition, and repetition of sentences. Clinical variables such as early age at seizure onset, severity of epilepsy, and polytherapy impaired distinct types of memory. These data confirm that children with MTS have episodic memory deficits and add new information on semantic memory. The data also demonstrate that clinical variables contribute differently to episodic and semantic memory performance. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Intact information sampling in mesial temporal lobe epilepsy.

    Science.gov (United States)

    Zamarian, Laura; Trinka, Eugen; Kuchukhidze, Giorgi; Bodner, Thomas; Unterberger, Iris; Luef, Gerhard; Delazer, Margarete

    2015-11-01

    Previous studies have reported deficits in decision making under ambiguity for patients with mesial temporal lobe epilepsy (mTLE). It is unknown whether mTLE is also associated with alterations at a predecisional stage. This study aimed to gain insight into predecisional processing of patients with mTLE. We compared performance of patients with mTLE (n = 25) with that of healthy controls (n = 75) on the information sampling task (IST), a task assessing reflection-impulsivity and predecisional information sampling. Patients and healthy controls showed a similar performance pattern in both conditions of the IST as indicated by the amount of information gathered, the degree of uncertainty tolerated, and the number of decision errors made. They both also demonstrated a significant sensitivity to the different reward characteristics of the task. For the patient group, we found no significant effects on performance on the IST of epilepsy lateralization, abnormality side, structural abnormality (hippocampus vs. amygdala), and medication (monotherapy vs. polytherapy). Reflection processes and predecisional information sampling as tested by the IST are intact in mTLE. Patients collect as much information as healthy individuals and adapt their behavior according to the changing reward conditions. Our findings indicate that in well-defined risk situations, where memory demands are sufficiently minimized, patients with mTLE should be able to gather sufficient information, weight risks and benefits, and make advantageous decisions. (c) 2015 APA, all rights reserved).

  2. Electroencephalography in Mesial Temporal Lobe Epilepsy: A Review

    Science.gov (United States)

    Javidan, Manouchehr

    2012-01-01

    Electroencephalography (EEG) has an important role in the diagnosis and classification of epilepsy. It can provide information for predicting the response to antiseizure drugs and to identify the surgically remediable epilepsies. In temporal lobe epilepsy (TLE) seizures could originate in the medial or lateral neocortical temporal region, and many of these patients are refractory to medical treatment. However, majority of patients have had excellent results after surgery and this often relies on the EEG and magnetic resonance imaging (MRI) data in presurgical evaluation. If the scalp EEG data is insufficient or discordant, invasive EEG recording with placement of intracranial electrodes could identify the seizure focus prior to surgery. This paper highlights the general information regarding the use of EEG in epilepsy, EEG patterns resembling epileptiform discharges, and the interictal, ictal and postictal findings in mesial temporal lobe epilepsy using scalp and intracranial recordings prior to surgery. The utility of the automated seizure detection and computerized mathematical models for increasing yield of non-invasive localization is discussed. This paper also describes the sensitivity, specificity, and predictive value of EEG for seizure recurrence after withdrawal of medications following seizure freedom with medical and surgical therapy. PMID:22957235

  3. The circuit of Papez in mesial temporal sclerosis: MRI

    International Nuclear Information System (INIS)

    Oikawa, H.; Sasaki, M.; Tamakawa, Y.; Kamei, A.

    2001-01-01

    We looked at abnormalities in the circuit of Papez in patients with the mesial temporal sclerosis (MTS). We reviewed the MRI studies of 15 patients with probable MTS, seeking changes in the fornix, mamillary body, mamillothalamic tract, thalamus and cingulate and parahippocampal gyri. We correlated any abnormalities with each other and with clinical severity. Atrophy and/or signal change in one or more structures in the circuit of Papez were found in five patients. They involved the parahippocampal gyri in all five, the fornices in four, mamillary bodies in three, the thalamus in two and the cingulate gyrus in one. Changes in the fornix, mamillary body, thalamus or cingulate gyrus were always accompanied by hippocampal and parahippocampal atrophy. The patients with abnormalities of the circuit of Papez did not have more severe epilepsy than those without. Changes in the parahippocampal gyrus, including the entorhinal cortex and subiculum, in which forniceal fibres originate, may be crucial in causing abnormalities more distally in the circuit. (orig.)

  4. Exome sequencing identifies SUCO mutations in mesial temporal lobe epilepsy.

    Science.gov (United States)

    Sha, Zhiqiang; Sha, Longze; Li, Wenting; Dou, Wanchen; Shen, Yan; Wu, Liwen; Xu, Qi

    2015-03-30

    Mesial temporal lobe epilepsy (mTLE) is the main type and most common medically intractable form of epilepsy. Severity of disease-based stratified samples may help identify new disease-associated mutant genes. We analyzed mRNA expression profiles from patient hippocampal tissue. Three of the seven patients had severe mTLE with generalized-onset convulsions and consciousness loss that occurred over many years. We found that compared with other groups, patients with severe mTLE were classified into a distinct group. Whole-exome sequencing and Sanger sequencing validation in all seven patients identified three novel SUN domain-containing ossification factor (SUCO) mutations in severely affected patients. Furthermore, SUCO knock down significantly reduced dendritic length in vitro. Our results indicate that mTLE defects may affect neuronal development, and suggest that neurons have abnormal development due to lack of SUCO, which may be a generalized-onset epilepsy-related gene. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  5. Imagining Sound

    DEFF Research Database (Denmark)

    Grimshaw, Mark; Garner, Tom Alexander

    2014-01-01

    We make the case in this essay that sound that is imagined is both a perception and as much a sound as that perceived through external stimulation. To argue this, we look at the evidence from auditory science, neuroscience, and philosophy, briefly present some new conceptual thinking on sound...... that accounts for this view, and then use this to look at what the future might hold in the context of imagining sound and developing technology....

  6. Shear bond strength of porcelain laminate veneers to enamel, dentine and enamel-dentine complex bonded with different adhesive luting systems.

    Science.gov (United States)

    Öztürk, Elif; Bolay, Şükran; Hickel, Reinhard; Ilie, Nicoleta

    2013-02-01

    The aim of this study was to evaluate the shear bond strength of porcelain laminate veneers to 3 different surfaces by means of enamel, dentine, and enamel-dentine complex. One hundred thirty-five extracted human maxillary central teeth were used, and the teeth were randomly divided into 9 groups (n=15). The teeth were prepared with 3 different levels for bonding surfaces of enamel (E), dentine (D), and enamel-dentine complex (E-D). Porcelain discs (IPS e.max Press, Ivoclar Vivadent) of 2mm in thickness and 4mm in diameter were luted to the tooth surfaces by using 2 light-curing (RelyX Veneer [RV], 3M ESPE; Variolink Veneer [VV], Ivoclar Vivadent) and a dual-curing (Variolink II [V2], Ivoclar Vivadent) adhesive systems according to the manufacturers' instructions. Shear bond strength test was performed in a universal testing machine at 0.5mm/min until bonding failure. Failure modes were determined under a stereomicroscope, and fracture surfaces were evaluated with a scanning electron microscope. The data were statistically analysed (SPSS 17.0) (p=0.05). Group RV-D exhibited the lowest bond strength value (5.42±6.6MPa). There was statistically no difference among RV-D, V2-D (13.78±8.8MPa) and VV-D (13.84±6.2MPa) groups (p>0.05). Group VV-E exhibited the highest bond strength value (24.76±8.8MPa). The type of tooth structure affected the shear bond strength of the porcelain laminate veneers to the 3 different types of tooth structures (enamel, dentine, and enamel-dentine complex). When dentine exposure is necessary during preparation, enough sound enamel must be protected as much as possible to maintain a good bonding; to obtain maximum bond strength, preparation margins should be on sound enamel. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Potential of nano-silver fluoride for tooth enamel caries prevention

    Science.gov (United States)

    Silva, Amitis V. C.; Mota, Cláudia C. B. O.; Teixeira, Joás. A.; Lins, Emery C.; Gomes, Anderson S. L.; Rosenblatt, Aronita

    2018-02-01

    This ex vivo study evaluated the efficiency of nano-silver fluoride (NSF) to enamel remineralization of deciduous teeth submitted to a high cariogenic challenge. 33 specimens of sound enamel were distributed into three groups: treated with sodium fluoride, with NSF, and deionized water. All specimens were submitted to microhardness test before chemical caries induction; post-induction of caries; and post-cariogenic challenge. The high cariogenic challenge was carried out in 14 daily cycles. There was no significant statistical difference (p=0.958) of enamel microhardness between NSFtreated and NaF-treated specimens. However, it presented significant difference between water-treated specimens and both NSF-treated and NaF-treated specimens (p=0.003).Furthermore, optical coherence tomography was employed for caries diagnosis, as it can be used in clinical environment.

  8. Age-Dependent Mesial Temporal Lobe Lateralization in Language FMRI

    Science.gov (United States)

    Sepeta, Leigh N.; Berl, Madison M.; Wilke, Marko; You, Xiaozhen; Mehta, Meera; Xu, Benjamin; Inati, Sara; Dustin, Irene; Khan, Omar; Austermuehle, Alison; Theodore, William H.; Gaillard, William D.

    2015-01-01

    Objective FMRI activation of the mesial temporal lobe (MTL) may be important for epilepsy surgical planning. We examined MTL activation and lateralization during language fMRI in children and adults with focal epilepsy. Methods 142 controls and patients with left hemisphere focal epilepsy (Pediatric: epilepsy, n = 17, mean age = 9.9 ± 2.0; controls, n = 48; mean age = 9.1 ± 2.6; Adult: epilepsy, n = 20, mean age = 26.7 ± 5.8; controls, n = 57, mean age = 26.2 ± 7.5) underwent 3T fMRI using a language task (auditory description decision task). Image processing and analyses were conducted in SPM8; ROIs included MTL, Broca’s area, and Wernicke’s area. We assessed group and individual MTL activation, and examined degree of lateralization. Results Patients and controls (pediatric and adult) demonstrated group and individual MTL activation during language fMRI. MTL activation was left lateralized for adults but less so in children (p’s < 0.005). Patients did not differ from controls in either age group. Stronger left-lateralized MTL activation was related to older age (p = 0.02). Language lateralization (Broca’s and Wernicke’s) predicted 19% of the variance in MTL lateralization for adults (p = 0.001), but not children. Significance Language fMRI may be used to elicit group and individual MTL activation. The developmental difference in MTL lateralization and its association with language lateralization suggests a developmental shift in lateralization of MTL function, with increased left lateralization across the age span. This shift may help explain why children have better memory outcomes following resection compared to adults. PMID:26696589

  9. Stereotactic radiosurgery for the treatment of mesial temporal lobe epilepsy.

    Science.gov (United States)

    Feng, E-S; Sui, C-B; Wang, T-X; Sun, G-L

    2016-12-01

    Stereotactic radiosurgery (RS) is a potential option for some patients with temporal lobe epilepsy (TLE). The aim of this meta-analysis was to determine the pooled seizure-free rate and the time interval to seizure cessation in patients with lesions in the mesial temporal lobe, and who were eligible for either stereotactic or gamma knife RS. We searched the Medline, Cochrane, EMBASE, and Google Scholar databases using combinations of the following terms: RS, stereotactic radiosurgery, gamma knife, and TLE. We screened 103 articles and selected 13 for inclusion in the meta-analysis. Significant study heterogeneity was detected; however, the included studies displayed an acceptable level of quality. We show that approximately half of the patients were seizure free over a follow-up period that ranged from 6 months to 9 years [pooled estimate: 50.9% (95% confidence interval: 0.381-0.636)], with an average of 14 months to seizure cessation [pooled estimate: 14.08 months (95% confidence interval: 11.95-12.22 months)]. Nine of 13 included studies reported data for adverse events (AEs), which included visual field deficits and headache (the two most common AEs), verbal memory impairment, psychosis, psychogenic non-epileptic seizures, and dysphasia. Patients in the individual studies experienced AEs at rates that ranged from 8%, for non-epileptic seizures, to 85%, for headache. Our findings indicate that RS may have similar or slightly less efficacy in some patients compared with invasive surgery. Randomized controlled trials of both treatment regimens should be undertaken to generate an evidence base for patient decision-making. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Neuronal autoantibodies in mesial temporal lobe epilepsy with hippocampal sclerosis.

    Science.gov (United States)

    Vanli-Yavuz, Ebru Nur; Erdag, Ece; Tuzun, Erdem; Ekizoglu, Esme; Baysal-Kirac, Leyla; Ulusoy, Canan; Peach, Sian; Gundogdu, Gokcen; Sencer, Serra; Sencer, Altay; Kucukali, Cem Ismail; Bebek, Nerses; Gurses, Candan; Gokyigit, Aysen; Baykan, Betul

    2016-07-01

    Our aim was to investigate the prevalence of neuronal autoantibodies (NAbs) in a large consecutive series with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) and to elucidate the clinical and laboratory clues for detection of NAbs in this prototype of frequent, drug-resistant epilepsy syndrome. Consecutive patients diagnosed with MTLE fulfilling the MRI criteria for HS were enrolled. The sera of patients and various control groups (80 subjects) were tested for eight NAbs after ethical approval and signed consents. Brain tissues obtained from surgical specimens were also investigated by immunohistochemical analysis for the presence of inflammatory infiltrates. The features of seropositive versus seronegative groups were compared and binary logistic regression analysis was performed to explore the differentiating variables. We found antibodies against antigens, contactin-associated protein-like 2 in 11 patients, uncharacterised voltage-gated potassium channel (VGKC)-complex antigens in four patients, glycine receptor (GLY-R) in 5 patients, N-methyl-d-aspartate receptor in 4 patients and γ-aminobutyric acid receptor A in 1 patient of 111 patients with MTLE-HS and none of the control subjects. The history of status epilepticus, diagnosis of psychosis and positron emission tomography or single-photon emission CT findings in temporal plus extratemporal regions were found significantly more frequently in the seropositive group. Binary logistic regression analysis disclosed that status epilepticus, psychosis and cognitive dysfunction were statistically significant variables to differentiate between the VGKC-complex subgroup versus seronegative group. This first systematic screening study of various NAbs showed 22.5% seropositivity belonging mostly to VGKC-complex antibodies in a large consecutive series of patients with MTLE-HS. Our results indicated a VGKC-complex autoimmunity-related subgroup in the syndrome of MTLE-HS. Published by the BMJ

  11. Deviations of Mesial Root Canals of Mandibular First Molar Teeth at the Apical Third: A Micro-computed Tomographic Study.

    Science.gov (United States)

    Keles, Ali; Keskin, Cangül

    2018-04-19

    The present study aimed to quantitatively analyze apical foramen deviations of mesial root canals of mandibular first molar teeth by means of micro-computed tomographic (micro-CT) imaging. Micro-CT images of the mesial roots of 109 mandibular first molar teeth with independent mesiobuccal (MB) and mesiolingual (ML) root canals were analyzed. The deviations of the apical foramina of the MB, ML, and middle mesial root canals from the anatomic apex were measured. The vertical distance between the apical foramina of each mesial root canal in relation to each other was also calculated. The distances from the apical foramina of the MB, ML, and middle mesial root canals to the anatomic apex of the mesial root were up to 2.51 mm, 3.21 mm, and 5.67 mm, respectively. There was no significant difference between the deviations of MB and ML root canals from each other (P > .05). The middle mesial root canal showed the greatest deviation compared with the MB and ML canals (P < .05). The apical foramina of mesial root canals of mandibular first molar teeth showed greater variations from each other and anatomic apices than previously reported. Clinically, the use of electronic apex locators for the detection of minor apical foramen of each mesial root canal is of the utmost important. Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  12. Effect of dentifrice containing fluoride and/or baking soda on enamel demineralization/remineralization: an in situ study.

    Science.gov (United States)

    Cury, J A; Hashizume, L N; Del Bel Cury, A A; Tabchoury, C P

    2001-01-01

    The additive effect of baking soda on the anticariogenic effect of fluoride dentifrice is not well established. To evaluate it, a crossover in situ study was done in three phases of 28 days. Volunteers, using acrylic palatal appliances containing four human enamel blocks, two sound (to evaluate demineralization) and two with artificial caries lesions (to evaluate remineralization), took part in this study. During each phase, 10% sucrose solution was dripped (3 times a day) only onto the sound blocks. After 10 min, a slurry of placebo, fluoride (F) or fluoride and baking soda (F+NaHCO(3)) dentifrice was dripped onto all enamel blocks. The results showed a higher F concentration in dental plaque formed during treatment with F+NaHCO(3) than placebo (pbaking soda neither improves nor impairs the effect of F dentifrice on reduction of demineralization and enhancement of remineralization of enamel.

  13. Effects of blue light irradiation on dental enamel remineralization in vitro

    International Nuclear Information System (INIS)

    Kato, Ilka Tiemy

    2009-01-01

    This study aimed to investigate the effects of blue radiation on dental enamel remineralization. In addition, a methodology of analysis was developed to evaluate alterations of enamel mineral content by optical coherence tomography. Artificial lesions were formed in bovine dental enamel slabs by immersing the samples in under saturated acetate buffer (2 mL/mm 2 e 6.25 mL/mm 2 ). The lesions were irradiated with blue LED (l=455±20nm), with radiant power of 110 mW, irradiance of 1.4 W/cm 2 , radiant exposure of 13.8 J/ c m2 and exposure time of 10 s. Remineralization was induced by pH-cycling model during 8 days. Cross-sectional hardness and optical coherence tomography (OCT) were used to assess mineral changes after remineralization. Hardness data showed that non-irradiated enamel lesions presented higher mineral content than irradiated ones and this difference was more evident in lesions formed in higher solution volume. The analysis of OCT signal also demonstrated that the mineral content of non-irradiated group was higher than in irradiated one; however, no significant difference was observed. Furthermore, significant differences in OCT sign were detected between sound and demineralized enamel. Based on the results obtained in the present study it can be concluded that blue radiation caused an inhibition of enamel remineralization. The methodology adopted for OCT analysis allowed the quantification of enamel mineral loss; however, the remineralization process could not be evaluated by this technique. (author)

  14. Enamel resistance to demineralization following Er:YAG laser etching for bonding orthodontic brackets

    Science.gov (United States)

    Ahrari, Farzaneh; Poosti, Maryam; Motahari, Pourya

    2012-01-01

    Background: Several studies have shown that laser-etching of enamel for bonding orthodontic brackets could be an appropriate alternative for acid conditioning, since a potential advantage of laser could or might be caries prevention. This study compared enamel resistance to demineralization following etching with acid phosphoric or Er:YAG laser for bonding orthodontic brackets. Materials and Methods: Fifty sound human premolars were divided into two equal groups. In the first group, enamel was etched with 37% phosphoric acid for 15 seconds. In the second group, Er:YAG laser (wavelength, 2 940 nm; 300 mJ/pulse, 10 pulses per second, 10 seconds) was used for tooth conditioning. The teeth were subjected to 4-day PH-cycling process to induce caries-like lesions. The teeth were then sectioned and the surface area of the lesion was calculated in each microphotographs and expressed in pixel. The total surface of each specimen was 196 608 pixels. Results: Mean lesion areas were 7 171 and 7532 pixels for Laser-etched and Acid-etched groups, respectively. The two sample t-test showed that there was no significant difference in lesion area between the two groups (P = 0.914). Conclusion: Although Er:YAG laser seems promising for etching enamel before bonding orthodontic brackets, it does not reduce enamel demineralization when exposed to acid challenge. PMID:23162591

  15. Shear bond strength of self-etch adhesives to enamel with additional phosphoric acid etching.

    Science.gov (United States)

    Lührs, Anne-Katrin; Guhr, Silke; Schilke, Reinhard; Borchers, Lothar; Geurtsen, Werner; Günay, Hüsamettin

    2008-01-01

    This study evaluated the shear bond strength of self-etch adhesives to enamel and the effect of additional phosphoric acid etching. Seventy sound human molars were randomly divided into three test groups and one control group. The enamel surfaces of the control group (n=10) were treated with Syntac Classic (SC). Each test group was subdivided into two groups (each n=10). In half of each test group, ground enamel surfaces were coated with the self-etch adhesives AdheSe (ADH), Xeno III (XE) or Futurabond NR (FNR). In the remaining half of each test group, an additional phosphoric acid etching of the enamel surface was performed prior to applying the adhesives. The shear bond strength was measured with a universal testing machine at a crosshead speed of 1 mm/minute after storing the samples in distilled water at 37 degrees C for 24 hours. Fracture modes were determined by SEM examination. For statistical analysis, one-way ANOVA and the two-sided Dunnett Test were used (p>0.05). Additional phosphoric etching significantly increased the shear bond strength of all the examined self-etch adhesives (padhesive fractures. For all the self-etch adhesives, a slight increase in mixed fractures occurred after conditioning with phosphoric acid. An additional phosphoric acid etching of enamel should be considered when using self-etch adhesives. More clinical studies are needed to evaluate the long-term success of the examined adhesives.

  16. Re- and Demineralization Characteristics of Enamel Depending on Baseline Mineral Loss and Lesion Depth in situ.

    Science.gov (United States)

    Wierichs, Richard J; Lausch, Julian; Meyer-Lueckel, Hendrik; Esteves-Oliveira, Marcella

    2016-01-01

    The aim of this double-blinded, randomized, cross-over in situ study was to evaluate the re- and demineralization characteristics of sound enamel as well as lowly and highly demineralized caries-like enamel lesions after the application of different fluoride compounds. In each of three experimental legs of 4 weeks, 21 participants wore intraoral mandibular appliances containing 4 bovine enamel specimens (2 lowly and 2 highly demineralized). Each specimen included one sound enamel and either one lowly demineralized (7 days, pH 4.95) or one highly demineralized (21 days, pH 4.95) lesion, and was positioned 1 mm below the acrylic under a plastic mesh. The three randomly allocated treatments (application only) included the following dentifrices: (1) 1,100 ppm F as NaF, (2) 1,100 ppm F as SnF2 and (3) 0 ppm F (fluoride-free) as negative control. Differences in integrated mineral loss (x0394;x0394;Z) and lesion depth (x0394;LD) were calculated between values before and after the in situ period using transversal microradiography. Of the 21 participants, 6 did not complete the study and 2 were excluded due to protocol violation. Irrespectively of the treatment, higher baseline mineral loss and lesion depth led to a less pronounced change in mineral loss and lesion depth. Except for x0394;x0394;Z of the dentifrice with 0 ppm F, sound surfaces showed significantly higher x0394;x0394;Z and x0394;LD values compared with lowly and highly demineralized lesions (p test). Re- and demineralization characteristics of enamel depended directly on baseline mineral loss and lesion depth. Treatment groups should therefore be well balanced with respect to baseline mineral loss and lesion depth. © 2016 S. Karger AG, Basel.

  17. Unsound Sound

    DEFF Research Database (Denmark)

    Knakkergaard, Martin

    2016-01-01

    This article discusses the change in premise that digitally produced sound brings about and how digital technologies more generally have changed our relationship to the musical artifact, not simply in degree but in kind. It demonstrates how our acoustical conceptions are thoroughly challenged...... by the digital production of sound and, by questioning the ontological basis for digital sound, turns our understanding of the core term substance upside down....

  18. The electrical resistance of enamel-dentine cylinders. Influence of NaCl content in storage solutions

    NARCIS (Netherlands)

    Gente, M; Pieper, K; Arends, J

    Objectives. To investigate the influence of different electrolyte concentrations on the electrical resistance of sound human enamel-dentine cylinders in vitro. Methods: Forty cylinders of 3-mm diameter and 2-mm length were drilled from 40 extracted caries-free third molar teeth. For ease of handling

  19. A comparative evaluation of four restorative materials to support undermined occlusal enamel of permanent teeth

    Directory of Open Access Journals (Sweden)

    Prabhakar A

    2006-09-01

    Full Text Available The purpose of this study was to test the support to undermined occlusal enamel provided by posterior restorative composite (FiltekTM P60, 3M Dental products USA, polyacid modified resin composite (F2000 compomer, 3M Dental products, USA., radiopaque silver alloy-glass ionomer cement (Miracle Mix. GC Corp, Tokyo, Japan and Glass Ionomer cement (Fuji IX GP. To test each material, 20 human permanent mandibular third molars were selected. The lingual cusps were removed and the dentin supporting the facial cusps was cut away, leaving a shell of enamel. Each group of prepared teeth was restored using the materials according to the manufacturer′s instructions. All the specimens were thermocycled (250 cycles, 6°C- 60°C, dwell time 30 seconds and then mounted on an acrylic base. Specimens were loaded evenly across the cusp tips at a crosshead speed of 5 mm /minute in Hounsfield universal testing machine until fracture occurred. Data obtained was analyzed using analysis of variance and Studentized- Newman- Keul′s range test. No significant differences were detected in the support provided by P-60, F 2000, Miracle Mix or Fuji IX GP groups. The support provided to undermined occlusal enamel by these materials was intermediate between no support and that provided by sound dentin. Without further development in dental material technology and evidence of its efficacy, restorative materials should not be relied upon to support undermined occlusal enamel to a level comparable to that provided by sound dentin.

  20. Sound Absorbers

    Science.gov (United States)

    Fuchs, H. V.; Möser, M.

    Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

  1. Dental enamel cells express functional SOCE channels.

    Science.gov (United States)

    Nurbaeva, Meerim K; Eckstein, Miriam; Concepcion, Axel R; Smith, Charles E; Srikanth, Sonal; Paine, Michael L; Gwack, Yousang; Hubbard, Michael J; Feske, Stefan; Lacruz, Rodrigo S

    2015-10-30

    Dental enamel formation requires large quantities of Ca(2+) yet the mechanisms mediating Ca(2+) dynamics in enamel cells are unclear. Store-operated Ca(2+) entry (SOCE) channels are important Ca(2+) influx mechanisms in many cells. SOCE involves release of Ca(2+) from intracellular pools followed by Ca(2+) entry. The best-characterized SOCE channels are the Ca(2+) release-activated Ca(2+) (CRAC) channels. As patients with mutations in the CRAC channel genes STIM1 and ORAI1 show abnormal enamel mineralization, we hypothesized that CRAC channels might be an important Ca(2+) uptake mechanism in enamel cells. Investigating primary murine enamel cells, we found that key components of CRAC channels (ORAI1, ORAI2, ORAI3, STIM1, STIM2) were expressed and most abundant during the maturation stage of enamel development. Furthermore, inositol 1,4,5-trisphosphate receptor (IP3R) but not ryanodine receptor (RyR) expression was high in enamel cells suggesting that IP3Rs are the main ER Ca(2+) release mechanism. Passive depletion of ER Ca(2+) stores with thapsigargin resulted in a significant raise in [Ca(2+)]i consistent with SOCE. In cells pre-treated with the CRAC channel blocker Synta-66 Ca(2+) entry was significantly inhibited. These data demonstrate that enamel cells have SOCE mediated by CRAC channels and implicate them as a mechanism for Ca(2+) uptake in enamel formation.

  2. Influence of de/remineralization of enamel on the tensile bond strength of etch-and-rinse and self-etching adhesives.

    Science.gov (United States)

    Farias de Lacerda, Ana Julia; Ferreira Zanatta, Rayssa; Crispim, Bruna; Borges, Alessandra Bühler; Gomes Torres, Carlos Rocha; Tay, Franklin R; Pucci, Cesar Rogério

    2016-10-01

    To evaluate the bonding behavior of resin composite and different adhesives applied to demineralized or remineralized enamel. Bovine tooth crowns were polished to prepare a 5 mm2 enamel bonding area, and divided into five groups (n= 48) according to the surface treatment: CONT (sound enamel control), DEM (demineralized with acid to create white spot lesions), REMS (DEM remineralized with artificial saliva), REMF (DEM remineralized with sodium fluoride) and INF (DEM infiltrated with Icon resin infiltrant). The surface-treated teeth were divided into two subgroups (n= 24) according to adhesive type: ER (etch-and-rinse; Single Bond Universal) and SE (self-etching; Clearfill S3 Bond), and further subdivided into two categories (n= 12) according to aging process: Thermo (thermocycling) and NA (no aging). Composite blocks were made over bonded enamel and sectioned for microtensile bond strength (MTBS) testing. Data were analyzed with three-way ANOVA and post-hoc Tukey's test (α= 0.05). Significant differences were observed for enamel surface treatment (Padhesive type (PUniversal had higher MTBS than Clearfil S3 Bond; thermo-aging resulted in lower MTBS irrespective of adhesive type and surface treatment condition. The predominant failure mode was mixed for all groups. Enamel surface infiltrated with Icon does not interfere with adhesive resin bonding procedures. Treatment of enamel surface containing white spot lesions or cavities with cavosurface margins in partially-demineralized enamel can benefit from infiltration with a low viscosity resin infiltrant prior to adhesive bonding of resin composites.

  3. Femtosecond laser ablation of enamel

    Science.gov (United States)

    Le, Quang-Tri; Bertrand, Caroline; Vilar, Rui

    2016-06-01

    The surface topographical, compositional, and structural modifications induced in human enamel by femtosecond laser ablation is studied. The laser treatments were performed using a Yb:KYW chirped-pulse-regenerative amplification laser system (560 fs and 1030 nm) and fluences up to 14 J/cm2. The ablation surfaces were studied by scanning electron microscopy, grazing incidence x-ray diffraction, and micro-Raman spectroscopy. Regardless of the fluence, the ablation surfaces were covered by a layer of resolidified material, indicating that ablation is accompanied by melting of hydroxyapatite. This layer presented pores and exploded gas bubbles, created by the release of gaseous decomposition products of hydroxyapatite (CO2 and H2O) within the liquid phase. In the specimen treated with 1-kHz repetition frequency and 14 J/cm2, thickness of the resolidified material is in the range of 300 to 900 nm. The micro-Raman analysis revealed that the resolidified material contains amorphous calcium phosphate, while grazing incidence x-ray diffraction analysis allowed detecting traces of a calcium phosphate other than hydroxyapatite, probably β-tricalcium phosphate Ca3), at the surface of this specimen. The present results show that the ablation of enamel involves melting of enamel's hydroxyapatite, but the thickness of the altered layer is very small and thermal damage of the remaining material is negligible.

  4. Sound generator

    NARCIS (Netherlands)

    Berkhoff, Arthur P.

    2008-01-01

    A sound generator, particularly a loudspeaker, configured to emit sound, comprising a rigid element (2) enclosing a plurality of air compartments (3), wherein the rigid element (2) has a back side (B) comprising apertures (4), and a front side (F) that is closed, wherein the generator is provided

  5. Sound generator

    NARCIS (Netherlands)

    Berkhoff, Arthur P.

    2010-01-01

    A sound generator, particularly a loudspeaker, configured to emit sound, comprising a rigid element (2) enclosing a plurality of air compartments (3), wherein the rigid element (2) has a back side (B) comprising apertures (4), and a front side (F) that is closed, wherein the generator is provided

  6. Sound generator

    NARCIS (Netherlands)

    Berkhoff, Arthur P.

    2007-01-01

    A sound generator, particularly a loudspeaker, configured to emit sound, comprising a rigid element (2) enclosing a plurality of air compartments (3), wherein the rigid element (2) has a back side (B) comprising apertures (4), and a front side (F) that is closed, wherein the generator is provided

  7. A clinical approach to the successful management of variations of middle mesial canals: A case series

    Directory of Open Access Journals (Sweden)

    Raghavendra Penukonda

    2018-01-01

    Full Text Available The possible variations of anatomical and morphological characteristics of the teeth are very important especially for the endodontic practitioners for successful treatment. Mandibular molars are most commonly affected by dental caries and require endodontic treatment. Mandibular molars exhibit variations in its internal anatomy; one among those is the presence of an extra canal in the mesial root called as middle mesial (MM canal. Detection of these minute canals requires a proper clinical knowledge and radiographic examination. This article presents the treatment of three cases of mandibular first molars with MM canals without the aid of any magnification devices.

  8. Time reversibility of intracranial human EEG recordings in mesial temporal lobe epilepsy

    Science.gov (United States)

    van der Heyden, M. J.; Diks, C.; Pijn, J. P. M.; Velis, D. N.

    1996-02-01

    Intracranial electroencephalograms from patients suffering from mesial temporal lobe epilepsy were tested for time reversibility. If the recorded time series is irreversible, the input of the recording system cannot be a realisation of a linear Gaussian random process. We confirmed experimentally that the measurement equipment did not introduce irreversibility in the recorded output when the input was a realisation of a linear Gaussian random process. In general, the non-seizure recordings are reversible, whereas the seizure recordings are irreversible. These results suggest that time reversibility is a useful property for the characterisation of human intracranial EEG recordings in mesial temporal lobe epilepsy.

  9. Surface variations affecting human dental enamel studied using nanomechanical and chemical analysis

    Science.gov (United States)

    Dickinson, Michelle Emma

    The enamel surface is the interface between the tooth and its ever changing oral environment. Cavity (caries) formation and extrinsic tooth staining are due, respectively, to degradation of the enamel structure under low pH conditions and interactions between salivary pellicle and dietary elements. Both of these occur at the enamel surface and are caused by the local environment changing the chemistry of the surface. The results can be detrimental to the enamel's mechanical integrity and aesthetics. Incipient carious lesions are the precursor to caries and form due to demineralisation of enamel. These carious lesions are a reversible structure where ions (e.g. Ca2+, F -) can diffuse in (remineralisation) to preserve the tooth's structural integrity. This investigation used controlled in vitro demineralisation and remineralisation to study artificial carious lesion formation and repair. The carious lesions were cross-sectioned and characterised using nanoindentation, electron probe micro-analysis and time of flight secondary ion mass spectrometry. Mechanical and chemical maps showed the carious lesion had a significantly reduced hardness and elastic modulus, and the calcium and phosphate content was lower than in sound enamel. Fluoride based remineralisation treatments gave a new phase (possibly fluorohydroxyapatite) within the lesion with mechanical properties higher than sound enamel. The acquired salivary pellicle is a protein-rich film formed by the physisorption of organic molecules in saliva onto the enamel surface. Its functions include lubrication during mastication and chemical protection. However, pellicle proteins react with dietary elements such as polyphenols (tannins in tea) causing a brown stain. This study has used in vitro dynamic nanoindentation and atomic force microscopy to examine normal and stained pellicles formed in vivo. The effects of polyphenols on the pellicle's mechanical properties and morphology have been studied. It was found that the

  10. Pattern of maxillary and mandibular proximal enamel thickness at the contact area of the permanent dentition from first molar to first molar.

    Science.gov (United States)

    Sarig, Rachel; Vardimon, Alexander D; Sussan, Celine; Benny, Lea; Sarne, Ofer; Hershkovitz, Israel; Shpack, Nir

    2015-04-01

    Proximal enamel thickness (PET) at the mesial and distal contact areas of the complete permanent dentition has not been previously reported. Anatomic investigation of PET is essential for interproximal reduction treatment. Our objectives were to measure the PETs of the complete maxillary and mandibular dentitions at the contact areas, to compare the PETs of adjacent teeth, and to evaluate the vertical position of each contact area. We evaluated 720 extracted teeth; of these, 109 intact teeth were selected. The mesial and distal contact areas were demarcated, and each tooth was embedded in transparent epoxy resin. Blocks were prepared so that the 2 demarcated contact areas were exposed, and 6 measurements were taken and statistically analyzed. Both jaws showed the same PET pattern characterized by 5 features: PET increased progressively from incisor (0.63 mm) to first molar (1.48 mm). Per tooth, mesial and distal PET did not differ. Total maxillary (26.86 mm) and mandibular (24.52 mm) PETs were similar. Paired PETs at the interproximal interface were similar, with the exception of the lateral incisor-canine interfaces. From incisor to first molar, the contact area becomes located farther gingivally. The existing guideline of maximal 0.5-mm interproximal reduction per 2 adjacent teeth should be kept in the anterior region and could be increased to 1 mm in the posterior region, when an equal amount is removed. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  11. Three-dimensional anatomy of equine incisors: tooth length, enamel cover and age related changes

    Science.gov (United States)

    2013-01-01

    Background Equine incisors are subjected to continuous occlusal wear causing multiple, age related changes of the extragingival crown. It is assumed that the occlusal wear is compensated by continued tooth elongation at the apical ends of the teeth. In this study, μCT-datasets offered the opportunity to analyze the three-dimensional appearance of the extra- and intraalveolar parts of the enamel containing dental crown as well as of the enamel-free dental root. Multiple morphometric measurements elucidated age related, morphological changes within the intraalveolar part of the incisors. Results Equine incisors possess a unique enamel cover displaying large indentations on the mesial and distal sides. After eruption tooth elongation at the apical end outbalances occlusal wear for two to four years resulting in increasing incisor length in this period of time. Remarkably, this maximum length is maintained for about ten years, up to a tooth age of 13 to 15 years post eruption. Variances in the total length of individual teeth are related to different Triadan positions (central-, middle- and corner incisors) as well as to the upper and lower arcades. Conclusion Equine incisors are able to fully compensate occlusal wear for a limited period of time. However, after this ability ceases, it is expected that a diminished intraalveolar tooth length will cause massive changes in periodontal biomechanics. The time point of these morphodynamic and biomechanical changes (13 to 15 years post eruption) occurs in coincidence with the onset of a recently described destructive disease of equine incisor (equine odontoclastic tooth resorption and hypercementosis) in aged horses. However, further biomechanical, cell biological and microbiological investigations are needed to elucidate a correlation between age related changes of incisor morphology and this disease. PMID:24321365

  12. Oriented and Ordered Biomimetic Remineralization of the Surface of Demineralized Dental Enamel Using HAP@ACP Nanoparticles Guided by Glycine

    Science.gov (United States)

    Wang, Haorong; Xiao, Zuohui; Yang, Jie; Lu, Danyang; Kishen, Anil; Li, Yanqiu; Chen, Zhen; Que, Kehua; Zhang, Qian; Deng, Xuliang; Yang, Xiaoping; Cai, Qing; Chen, Ning; Cong, Changhong; Guan, Binbin; Li, Ting; Zhang, Xu

    2017-01-01

    Achieving oriented and ordered remineralization on the surface of demineralized dental enamel, thereby restoring the satisfactory mechanical properties approaching those of sound enamel, is still a challenge for dentists. To mimic the natural biomineralization approach for enamel remineralization, the biological process of enamel development proteins, such as amelogenin, was simulated in this study. In this work, carboxymethyl chitosan (CMC) conjugated with alendronate (ALN) was applied to stabilize amorphous calcium phosphate (ACP) to form CMC/ACP nanoparticles. Sodium hypochlorite (NaClO) functioned as the protease which decompose amelogenin in vivo to degrade the CMC-ALN matrix and generate HAP@ACP core-shell nanoparticles. Finally, when guided by 10 mM glycine (Gly), HAP@ACP nanoparticles can arrange orderly and subsequently transform from an amorphous phase to well-ordered rod-like apatite crystals to achieve oriented and ordered biomimetic remineralization on acid-etched enamel surfaces. This biomimetic remineralization process is achieved through the oriented attachment (OA) of nanoparticles based on non-classical crystallization theory. These results indicate that finding and developing analogues of natural proteins such as amelogenin involved in the biomineralization by natural macromolecular polymers and imitating the process of biomineralization would be an effective strategy for enamel remineralization. Furthermore, this method represents a promising method for the management of early caries in minimal invasive dentistry (MID).

  13. Enamel Regeneration - Current Progress and Challenges

    Science.gov (United States)

    Baswaraj; H.K, Navin; K.B, Prasanna

    2014-01-01

    Dental Enamel is the outermost covering of teeth. It is hardest mineralized tissue present in the human body. Enamel faces the challenge of maintaining its integrity in a constant demineralization and remineralization within the oral environment and it is vulnerable to wear, damage, and decay. It cannot regenerate itself, because it is formed by a layer of cells that are lost after the tooth eruption. Conventional treatment relies on synthetic materials to restore lost enamel that cannot mimic natural enamel. With advances in material science and understanding of basic principles of organic matrix mediated mineralization paves a way for formation of synthetic enamel. The knowledge of enamel formation and understanding of protein interactions and their gene products function along with the isolation of postnatal stem cells from various sources in the oral cavity, and the development of smart materials for cell and growth factor delivery, makes possibility for biological based enamel regeneration. This article will review the recent endeavor on biomimetic synthesis and cell based strategies for enamel regeneration. PMID:25386548

  14. Sound Zones

    DEFF Research Database (Denmark)

    Møller, Martin Bo; Olsen, Martin

    2017-01-01

    Sound zones, i.e. spatially confined regions of individual audio content, can be created by appropriate filtering of the desired audio signals reproduced by an array of loudspeakers. The challenge of designing filters for sound zones is twofold: First, the filtered responses should generate...... an acoustic separation between the control regions. Secondly, the pre- and post-ringing as well as spectral deterioration introduced by the filters should be minimized. The tradeoff between acoustic separation and filter ringing is the focus of this paper. A weighted L2-norm penalty is introduced in the sound...

  15. Accelerated enamel mineralization in Dspp mutant mice

    Science.gov (United States)

    Verdelis, Kostas; Szabo-Rogers, Heather L.; Xu, Yang; Chong, Rong; Kang, Ryan; Cusack, Brian J.; Jani, Priyam; Boskey, Adele L.; Qin, Chunlin; Beniash, Elia

    2016-01-01

    Dentin sialophosphoprotein (DSPP) is one of the major non-collagenous proteins present in dentin, cementum and alveolar bone; it is also transiently expressed by ameloblasts. In humans many mutations have been found in DSPP and are associated with two autosomal-dominant genetic diseases — dentinogenesis imperfecta II (DGI-II) and dentin dysplasia (DD). Both disorders result in the development of hypomineralized and mechanically compromised teeth. The erupted mature molars of Dspp–/– mice have a severe hypomineralized dentin phenotype. Since dentin and enamel formations are interdependent, we decided to investigate the process of enamel onset mineralization in young Dspp–/– animals. We focused our analysis on the constantly erupting mouse incisor, to capture all of the stages of odontogenesis in one tooth, and the unerupted first molars. Using high-resolution microCT, we revealed that the onset of enamel matrix deposition occurs closer to the cervical loop and both secretion and maturation of enamel are accelerated in Dspp–/– incisors compared to the Dspp+/– control. Importantly, these differences did not translate into major phenotypic differences in mature enamel in terms of the structural organization, mineral density or hardness. The only observable difference was the reduction in thickness of the outer enamel layer, while the total enamel thickness remained unchanged. We also observed a compromised dentin-enamel junction, leading to delamination between the dentin and enamel layers. The odontoblast processes were widened and lacked branching near the DEJ. Finally, for the first time we demonstrate expression of Dspp mRNA in secretory ameloblasts. In summary, our data show that DSPP is important for normal mineralization of both dentin and enamel. PMID:26780724

  16. Fluoxetine Restores Spatial Learning but Not Accelerated Forgetting in Mesial Temporal Lobe Epilepsy

    Science.gov (United States)

    Barkas, Lisa; Redhead, Edward; Taylor, Matthew; Shtaya, Anan; Hamilton, Derek A.; Gray, William P.

    2012-01-01

    Learning and memory dysfunction is the most common neuropsychological effect of mesial temporal lobe epilepsy, and because the underlying neurobiology is poorly understood, there are no pharmacological strategies to help restore memory function in these patients. We have demonstrated impairments in the acquisition of an allocentric spatial task,…

  17. Improved Cerebral Function in Mesial Temporal Lobe Epilepsy after Subtemporal Amygdalohippocampectomy

    Science.gov (United States)

    Takaya, Shigetoshi; Mikuni, Nobuhiro; Mitsueda, Takahiro; Satow, Takeshi; Taki, Junya; Kinoshita, Masako; Miyamoto, Susumu; Hashimoto, Nobuo; Ikeda, Akio; Fukuyama, Hidenao

    2009-01-01

    The functional changes that occur throughout the human brain after the selective removal of an epileptogenic lesion remain unclear. Subtemporal selective amygdalohippocampectomy (SAH) has been advocated as a minimally invasive surgical procedure for patients with medically intractable mesial temporal lobe epilepsy (MTLE). We evaluated the effects…

  18. Enamel-Caries Prevention Using Two Applications of Fluoride-Laser Sequence.

    Science.gov (United States)

    Noureldin, Amal; Quintanilla, Ines; Kontogiorgos, Elias; Jones, Daniel

    2016-03-01

    Studies demonstrated a significant synergism between fluoride and laser in reduction of enamel solubility. However, minimal research has focused on testing the sequence of their application and no other research investigated the preventive effect of repeated applications of a combined treatment. This study investigated the effect of two applications of fluoride-laser sequence on the resistance of sound enamel to cariogenic challenge compared to one-time application. Sixty enamel slabs were cut from 10 human incisors, ground flat, polished and coated with nail varnish except a 2 x 2 mm window. Specimens were randomly assigned into five groups of 12 specimens; (CON-) negative-control received no treatment, (CON+) positive-control received pH challenge, (FV) treated with M fluoride varnish, (F-L1) one-application fluoride-varnish followed by CO2 laser-treatment (short-pulsed 10.6 µm, 2.4J/ cm2, 10HZ, 10sec), and (F-L2) two-applications of fluoride varnish-laser treatment. Specimens were left in distilled water for one day between applications. Except CON-, all groups were submitted to pH cycling for 9-days (8 demin/ remin + 1 day remineralisation bath) at 37°C. Enamel demineralization was quantitatively evaluated by measurement of Knoop surface-microhardness (SM H) (50-grams/10 seconds). Data were analyzed using one-way ANOVA (p ≤ 0.05) followed by Duncan's Multiple Range Test. Within the limitations of this study, it was found that one or two applications of fluoride-laser sequence significantly improved resistance of the sound enamel surface to acid attack compared to FV-treated group. Although the two applications of fluoride-laser sequence (F-L1 and F-L2) showed higher SMH values, significant resistance to demineralization was only obtained with repeated applications.

  19. Sound intensity

    DEFF Research Database (Denmark)

    Crocker, Malcolm J.; Jacobsen, Finn

    1998-01-01

    This chapter is an overview, intended for readers with no special knowledge about this particular topic. The chapter deals with all aspects of sound intensity and its measurement from the fundamental theoretical background to practical applications of the measurement technique.......This chapter is an overview, intended for readers with no special knowledge about this particular topic. The chapter deals with all aspects of sound intensity and its measurement from the fundamental theoretical background to practical applications of the measurement technique....

  20. Sound Intensity

    DEFF Research Database (Denmark)

    Crocker, M.J.; Jacobsen, Finn

    1997-01-01

    This chapter is an overview, intended for readers with no special knowledge about this particular topic. The chapter deals with all aspects of sound intensity and its measurement from the fundamental theoretical background to practical applications of the measurement technique.......This chapter is an overview, intended for readers with no special knowledge about this particular topic. The chapter deals with all aspects of sound intensity and its measurement from the fundamental theoretical background to practical applications of the measurement technique....

  1. In vitro wear of four ceramic materials and human enamel on enamel antagonist.

    Science.gov (United States)

    Nakashima, Jun; Taira, Yohsuke; Sawase, Takashi

    2016-06-01

    The purpose of the present study was to evaluate the wear of four different ceramics and human enamel. The ceramics used were lithium disilicate glass (e.max Press), leucite-reinforced glass (GN-Ceram), yttria-stabilized zirconia (Aadva Zr), and feldspathic porcelain (Porcelain AAA). Hemispherical styli were fabricated with these ceramics and with tooth enamel. Flattened enamel was used for antagonistic specimens. After 100,000 wear cycles of a two-body wear test, the height and volume losses of the styli and enamel antagonists were determined. The mean and standard deviation for eight specimens were calculated and statistically analyzed using a non-parametric (Steel-Dwass) test (α = 0.05). GN-Ceram exhibited greater stylus height and volume losses than did Porcelain AAA. E.max Press, Porcelain AAA, and enamel styli showed no significant differences, and Aadva Zr exhibited the smallest stylus height and volume losses. The wear of the enamel antagonist was not significantly different among GN-Ceram, e.max Press, Porcelain AAA, and enamel styli. Aadva Zr resulted in significantly lower wear values of the enamel antagonist than did GN-Ceram, Porcelain AAA, and enamel styli. In conclusion, leucite-reinforced glass, lithium disilicate glass, and feldspathic porcelain showed wear values closer to those for human enamel than did yttria-stabilized zirconia. © 2016 Eur J Oral Sci.

  2. ON THE R-CURVE BEHAVIOR OF HUMAN TOOTH ENAMEL

    OpenAIRE

    Bajaj, Devendra; Arola, Dwayne

    2009-01-01

    In this study the crack growth resistance behavior and fracture toughness of human tooth enamel were quantified using incremental crack growth measures and conventional fracture mechanics. Results showed that enamel undergoes an increase in crack growth resistance (i.e. rising R-curve) with crack extension from the outer to the inner enamel, and that the rise in toughness is function of distance from the Dentin Enamel Junction (DEJ). The outer enamel exhibited the lowest apparent toughness (0...

  3. Compressive strength and failure types of cusp replacing direct resin composite restorations in previously amalgam-filled premolars versus sound teeth

    NARCIS (Netherlands)

    Scholtanus, Johannes Durk; Zaia, John; Oezcan, Mutlu

    2017-01-01

    This study evaluated the fracture resistance of cusp replacing direct resin composite restorations (DCR) in premolars that had been previously filled with amalgam mesial-occlusal-distal (MOD) restorations and compared their fracture resistance with those made on sound dentin and intact teeth.

  4. Regulation of Dental Enamel Shape and Hardness

    Science.gov (United States)

    Simmer, J.P.; Papagerakis, P.; Smith, C.E.; Fisher, D.C.; Rountrey, A.N.; Zheng, L.; Hu, J.C.-C.

    2010-01-01

    Epithelial-mesenchymal interactions guide tooth development through its early stages and establish the morphology of the dentin surface upon which enamel will be deposited. Starting with the onset of amelogenesis beneath the future cusp tips, the shape of the enamel layer covering the crown is determined by five growth parameters: the (1) appositional growth rate, (2) duration of appositional growth (at the cusp tip), (3) ameloblast extension rate, (4) duration of ameloblast extension, and (5) spreading rate of appositional termination. Appositional growth occurs at a mineralization front along the ameloblast distal membrane in which amorphous calcium phosphate (ACP) ribbons form and lengthen. The ACP ribbons convert into hydroxyapatite crystallites as the ribbons elongate. Appositional growth involves a secretory cycle that is reflected in a series of incremental lines. A potentially important function of enamel proteins is to ensure alignment of successive mineral increments on the tips of enamel ribbons deposited in the previous cycle, causing the crystallites to lengthen with each cycle. Enamel hardens in a maturation process that involves mineral deposition onto the sides of existing crystallites until they interlock with adjacent crystallites. Neutralization of acidity generated by hydroxyapatite formation is a key part of the mechanism. Here we review the growth parameters that determine the shape of the enamel crown as well as the mechanisms of enamel appositional growth and maturation. PMID:20675598

  5. Demineralization of Enamel in Primary Second Molars Related to Properties of the Enamel

    OpenAIRE

    Sabel, N.; Robertson, A.; Nietzsche, S.; Norén, J. G.

    2012-01-01

    Enamel structure is of importance in demineralization. Differences in porosity in enamel effect the rate of demineralization, seen between permanent and deciduous teeth. Individual differences have been shown in the mean mineral concentration values in enamel, the role of this in demineralization is not thoroughly investigated. The aim of this study was to study variations of depths of artificial lesions of demineralization and to analyze the depth in relation to variations in the chemical an...

  6. Weaker dental enamel explains dental decay.

    Science.gov (United States)

    Vieira, Alexandre R; Gibson, Carolyn W; Deeley, Kathleen; Xue, Hui; Li, Yong

    2015-01-01

    Dental caries continues to be the most prevalent bacteria-mediated non-contagious disease of humankind. Dental professionals assert the disease can be explained by poor oral hygiene and a diet rich in sugars but this does not account for caries free individuals exposed to the same risk factors. In order to test the hypothesis that amount of amelogenin during enamel development can influence caries susceptibility, we generated multiple strains of mice with varying levels of available amelogenin during dental development. Mechanical tests showed that dental enamel developed with less amelogenin is "weaker" while the dental enamel of animals over-expressing amelogenin appears to be more resistant to acid dissolution.

  7. The in vitro effect of fluoridated milk in a bacterial biofilm--enamel model.

    Science.gov (United States)

    Arnold, Wolfgang H; Forer, Stefan; Heesen, Joerg; Yudovich, Keren; Steinberg, Doron; Gaengler, Peter

    2006-07-01

    The purpose of this study was to investigate the effect of milk and fluoridated milk on bacterially induced caries-like lesions. Extracted impacted human molars were cut in half and covered with a varnish leaving a 4*4 mm window. The samples were coated with biofilm of S. sobrinus and were further divided into three experimental groups of S. sobrinus, S. sobrinus and milk and S. sobrinus and fluoridated milk. As negative controls served teeth incubated in saline. Of twenty tooth halves serial ground sections were cut through the lesions and investigated with polarization light microscopy (PLM) and scanning electron microscopy (SEM) and EDX element analysis. The PLM photographs were used for 3D reconstruction, volumetric assessment and determination of the extension of the lesion zones. Of eight tooth halves the biofilm on the enamel surface was studied with SEM and EDX element analysis. Volumetric assessment showed a statistically significant difference in the volume of the body of the lesion and the translucent zone between the milk group and fluoridated milk group. Quantitative element analysis demonstrated significant differences between sound enamel and the superficial layer in the fluoridated milk group. The biofilm on the enamel surface showed an increased Ca content in the milk group and fluoridated milk group. Milk as a common nutrient seems to play a complex role in in-vitro biofilm--enamel interactions stimulating bacterial demineralization on one hand, and, as effective fluoride carrier, inhibits caries-like demineralization.

  8. MMP20 Promotes a Smooth Enamel Surface, a Strong DEJ, and a Decussating Enamel Rod Pattern

    Science.gov (United States)

    Bartlett, John D.; Skobe, Ziedonis; Nanci, Antonio; Smith, Charles E.

    2012-01-01

    Mutations of the Matrix metalloproteinase-20 (MMP20, enamelysin) gene cause autosomal recessive amelogenesis imperfecta and Mmp20 ablated mice also have malformed dental enamel. Here we show that Mmp20 null mouse secretory stage ameloblasts maintained a columnar shape and were present as a single layer of cells. However, the null maturation stage ameloblasts covered extraneous nodules of ectopic calcified material formed at the enamel surface. Remarkably, nodule formation occurs in null mouse enamel when MMP20 is normally no longer expressed. The malformed enamel in Mmp20 null teeth was loosely attached to the dentin and the entire enamel layer tended to separate from the dentin indicative of a faulty DEJ. The enamel rod pattern was also altered in Mmp20 null mice. Each enamel rod is formed by a single ameloblast and is a mineralized record of the migration path of the ameloblast that formed it. The Mmp20 null mouse enamel rods were grossly malformed or were absent indicating that the ameloblasts do not migrate properly when backing away from the DEJ. Thus, MMP20 is required for ameloblast cell movement necessary to form the decussating enamel rod patterns, for the prevention of ectopic mineral formation, and to maintain a functional DEJ. PMID:22243247

  9. Fluid Sounds

    DEFF Research Database (Denmark)

    Explorations and analysis of soundscapes have, since Canadian R. Murray Schafer's work during the early 1970's, developed into various established research - and artistic disciplines. The interest in sonic environments is today present within a broad range of contemporary art projects and in arch......Explorations and analysis of soundscapes have, since Canadian R. Murray Schafer's work during the early 1970's, developed into various established research - and artistic disciplines. The interest in sonic environments is today present within a broad range of contemporary art projects...... and in architectural design. Aesthetics, psychoacoustics, perception, and cognition are all present in this expanding field embracing such categories as soundscape composition, sound art, sonic art, sound design, sound studies and auditory culture. Of greatest significance to the overall field is the investigation...

  10. Sound Settlements

    DEFF Research Database (Denmark)

    Mortensen, Peder Duelund; Hornyanszky, Elisabeth Dalholm; Larsen, Jacob Norvig

    2013-01-01

    Præsentation af projektresultater fra Interreg forskningen Sound Settlements om udvikling af bæredygtighed i det almene boligbyggerier i København, Malmø, Helsingborg og Lund samt europæiske eksempler på best practice......Præsentation af projektresultater fra Interreg forskningen Sound Settlements om udvikling af bæredygtighed i det almene boligbyggerier i København, Malmø, Helsingborg og Lund samt europæiske eksempler på best practice...

  11. Nuclear sound

    International Nuclear Information System (INIS)

    Wambach, J.

    1991-01-01

    Nuclei, like more familiar mechanical systems, undergo simple vibrational motion. Among these vibrations, sound modes are of particular interest since they reveal important information on the effective interactions among the constituents and, through extrapolation, on the bulk behaviour of nuclear and neutron matter. Sound wave propagation in nuclei shows strong quantum effects familiar from other quantum systems. Microscopic theory suggests that the restoring forces are caused by the complex structure of the many-Fermion wavefunction and, in some cases, have no classical analogue. The damping of the vibrational amplitude is strongly influenced by phase coherence among the particles participating in the motion. (author)

  12. Effect of Bioactive Glass air Abrasion on Shear Bond Strength of Two Adhesive Resins to Decalcified Enamel

    Science.gov (United States)

    Eshghi, Alireza; Khoroushi, Maryam; Rezvani, Alireza

    2014-01-01

    Objective: Bioactive glass air abrasion is a conservative technique to remove initial decalcified tissue and caries. This study examined the shear bond strength of composite resin to sound and decalcified enamel air-abraded by bioactive glass (BAG) or alumina using etch-and-rinse and self-etch adhesives. Materials and Methods: Forty-eight permanent molars were root-amputated and sectioned mesiodistally. The obtained 96 specimens were mounted in acrylic resin; the buccal and lingual surfaces remained exposed. A demineralizing solution was used to decalcify half the specimens. Both sound and decalcified specimens were divided into two groups of alumina and bioactive glass air abrasion. In each group, the specimens were subdivided into two subgroups of Clearfil SE Bond or OptiBond FL adhesives (n=12). Composite resin cylinders were bonded on enamel surfaces cured and underwent thermocycling. The specimens were tested for shear bond strength. Data were analyzed using SPSS 16.0 and three-way ANOVA (α=0.05). Similar to the experimental groups, the enamel surface of one specimen underwent SEM evaluation. Results: No significant differences were observed in composite resin bond strength subsequent to alumina or bioactive glass air abrasion preparation techniques (P=0.987). There were no statistically significant differences between the bond strength of etch-and-rinse and self-etch adhesive groups (P=1). Also, decalcified or intact enamel groups had no significant difference (P=0.918). However, SEM analysis showed much less enamel irregularities with BAG air abrasion compared to alumina air abrasion. Conclusion: Under the limitations of this study, preparation of both intact and decalcified enamel surfaces with bioactive glass air abrasion results in similar bond strength of composite resin in comparison with alumina air abrasion using etch-&-rinse or self-etch adhesives. PMID:25628694

  13. Effect of Bioactive Glass air Abrasion on Shear Bond Strength of Two Adhesive Resins to Decalcified Enamel.

    Directory of Open Access Journals (Sweden)

    Alireza Eshghi

    2014-12-01

    Full Text Available Bioactive glass air abrasion is a conservative technique to remove initial decalcified tissue and caries. This study examined the shear bond strength of composite resin to sound and decalcified enamel air-abraded by bioactive glass (BAG or alumina using etch-and-rinse and self-etch adhesives.Forty-eight permanent molars were root-amputated and sectioned mesiodistally. The obtained 96 specimens were mounted in acrylic resin; the buccal and lingual surfaces remained exposed. A demineralizing solution was used to decalcify half the specimens. Both sound and decalcified specimens were divided into two groups of alumina and bioactive glass air abrasion. In each group, the specimens were subdivided into two subgroups of Clearfil SE Bond or OptiBond FL adhesives (n=12. Composite resin cylinders were bonded on enamel surfaces cured and underwent thermocycling. The specimens were tested for shear bond strength. Data were analyzed using SPSS 16.0 and three-way ANOVA (α=0.05. Similar to the experimental groups, the enamel surface of one specimen underwent SEM evaluation.No significant differences were observed in composite resin bond strength subsequent to alumina or bioactive glass air abrasion preparation techniques (P=0.987. There were no statistically significant differences between the bond strength of etch-and-rinse and self-etch adhesive groups (P=1. Also, decalcified or intact enamel groups had no significant difference (P=0.918. However, SEM analysis showed much less enamel irregularities with BAG air abrasion compared to alumina air abrasion.Under the limitations of this study, preparation of both intact and decalcified enamel surfaces with bioactive glass air abrasion results in similar bond strength of composite resin in comparison with alumina air abrasion using etch-&-rinse or self-etch adhesives.

  14. Dental enamel, fluorosis and amoxicillin

    Directory of Open Access Journals (Sweden)

    I. Ciarrocchi

    2012-06-01

    Full Text Available Introduction: Amoxicillin is one of the most used antibiotics among pediatric patients for the treatment of upper respiratory tract infections and specially for acute otitis media (AOM, a common diseases of infants and childhood. It has been speculated that the use of amoxicillin during early childhood could be associated with dental enamel fluorosis, also described in literature with the term Molar Incisor Hypomineralization (MIH, because they are generally situated in one or more 1st permanent molars and less frequently in the incisors. The effect of Amoxicillin seems to be independent of other risk factors such as fluoride intake, prematurity, hypoxia, hypocalcaemia, exposure to dioxins, chikenpox, otitis media, high fever and could have a significant impact on oral health for the wide use of this drug in that period of life. Objective: The aim of this work was to review the current literature about the association between amoxicillin and fluorosis. Methods and Results: A literature survey was done by applying the Medline database (Entrez PubMed; the Cochrane Library database of the Cochrane Collaboration (CENTRAL. The databases were searched using the following strategy and keywords: amoxicillin* AND (dental fluorosis* OR dental enamel* AND MIH*. After selecting the studies, only three relevant articles published between 1966 and 2011 were included in the review. Conclusion: The presence of several methodological issues does not allow to draw any evidence-based conclusions. No evidence of association was detected, therefore, there is a need of further well-designed studies to assess the scientific evidence of the relationship between amoxicillin and fluorosis and to restrict the prescription of this drug for recurrent upper respiratory tract infections especially acute otitis media (AOM during the first two years of life. When it is possible can be opportune to use an alternative antibiotic treatment.

  15. Sound Settlements

    DEFF Research Database (Denmark)

    Mortensen, Peder Duelund; Hornyanszky, Elisabeth Dalholm; Larsen, Jacob Norvig

    2013-01-01

    Præsentation af projektresultater fra Interreg forskningen Sound Settlements om udvikling af bæredygtighed i det almene boligbyggerier i København, Malmø, Helsingborg og Lund samt europæiske eksempler på best practice...

  16. Second Sound

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 6. Second Sound - The Role of Elastic Waves. R Srinivasan. General Article Volume 4 Issue 6 June 1999 pp 15-19. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/004/06/0015-0019 ...

  17. Enamel micromorphology of the tribosphenic molar

    OpenAIRE

    Hanousková, Pavla

    2014-01-01

    The tribosphenic molar is an ancestral type of mammalian teeth and a phy- lotypic stage of the mammalian dental evolution. Yet, in contrast to derived teeth types, its enamel microarchitecture attracted only little attention and the information on that subject is often restricted to statements suggesting a simple homogenous arrangement of a primitive radial prismatic enamel. The present paper tests this prediction with aid of comparative study of eight model species representing the orders Ch...

  18. Middle mesial canal of the permanent mandibular first molars: an anatomical challenge directly related to the outcome of endodontic treatment.

    Science.gov (United States)

    Perlea, Paula; Nistor, Cristina Coralia; Imre, Marina; Gheorghiu, Irina Maria; Iliescu, Alexandru Andrei

    2017-01-01

    To effectively clean and shape the mandibular permanent first molars it is mandatory to understand in detail their complex internal anatomy. The middle mesial canal is an additional canal located between the usual mesiobuccal and mesiolingual canals in the mesial root of mandibular first molars. The incidence of the middle mesial canal, its relationship with main canals of the mesial root and the possibility for it to be negotiated is an important practical issue in endodontics. To identify the presence of this canal is mandatory. Accordingly, a modified endodontic access, the use of the operating microscope and periapical radiographs in two different horizontal projections are indicated to enhance the long-term favorable outcome of the endodontic treatment.

  19. EPR dosimetry with tooth enamel: A review

    International Nuclear Information System (INIS)

    Fattibene, Paola; Callens, Freddy

    2010-01-01

    When tooth enamel is exposed to ionizing radiation, radicals are formed, which can be detected using electron paramagnetic resonance (EPR) techniques. EPR dosimetry using tooth enamel is based on the (presumed) correlation between the intensity or amplitude of some of the radiation-induced signals with the dose absorbed in the enamel. In the present paper a critical review is given of this widely applied dosimetric method. The first part of the paper is fairly fundamental and deals with the main properties of tooth enamel and some of its model systems (e.g., synthetic apatites). Considerable attention is also paid to the numerous radiation-induced and native EPR signals and the radicals responsible for them. The relevant methods for EPR detection, identification and spectrum analyzing are reviewed from a general point of view. Finally, the needs for solid-state modelling and studies of the linearity of the dose response are investigated. The second part is devoted to the practical implementation of EPR dosimetry using enamel. It concerns specific problems of preparation of samples, their irradiation and spectrum acquisition. It also describes how the dosimetric signal intensity and dose can be retrieved from the EPR spectra. Special attention is paid to the energy dependence of the EPR response and to sources of uncertainties. Results of and problems encountered in international intercomparisons and epidemiological studies are also dealt with. In the final section the future of EPR dosimetry with tooth enamel is analyzed.

  20. Measurement of opalescence of tooth enamel.

    Science.gov (United States)

    Lee, Yong-Keun; Yu, Bin

    2007-08-01

    Opalescent dental esthetic restoratives look natural and esthetic in any light, react to light in the same manner as the natural tooth and show improved masking effect. The objective of this study was to determine the opalescence of tooth enamel with reflection spectrophotometers. Color of intact bovine and human enamel was measured in the reflectance and transmittance modes. Two kinds of spectrophotometers were used for bovine and one kind was used for human enamel. The opalescence parameter (OP) was calculated as the difference in yellow-blue color coordinate (CIE Deltab(*)) and red-green color coordinate (CIE Deltaa(*)) between the reflected and transmitted colors. Mean OP value of bovine enamel was 10.6 (+/-1.4) to 19.0 (+/-2.1), and varied by the configuration of spectrophotometers. Mean OP value of human enamel was 22.9 (+/-1.9). Opalescence varied by the configuration of measuring spectrophotometer and the species of enamel. These values could be used in the development of esthetic restorative materials.

  1. In-Vitro Comparative Study of In-office and Home Bleaching Agents on Surface Micro-morphology of Enamel.

    Science.gov (United States)

    Fatima, Nazish

    2016-01-01

    To evaluate the effect of home-use bleaching agent containing 16% Carbamide Peroxide (CP) and in-office bleaching agent with 38% Hydrogen Peroxide (HP) on surface micro-morphology of enamel. An experimental study. The discs were prepared at Material Engineering Department of NED University of Engineering and Technology, Karachi, and surface morphology was analyzed at Centralized Science Laboratory of Karachi University, Pakistan. Duration of study was one year from January to December 2012. Forty five sound human third molar crowns, extracted for periodontal reason, were included in the study. Longitudinal sections were made using diamond disks (0.2 mm) under water lubrication to obtain enamel slabs measuring (3 mm x 3 mm). The slabs were embedded in polystyrene resin by using 2.0 cm diameter PVC molds, leaving the outer enamel surface uncovered by the resin. Ninety dental enamel slabs were prepared. The slabs were then randomly divided into 3 groups. Each group contained thirty specimens (n=30). Group 1 was kept in artificial saliva at 37°C in incubator (Memart, Germany) during whole experiment. Group 2 was treated with power whitening gel (White Smile 2011, Germany). Group 3 was treated with tooth whitening pen (White Smile 2011, Germany). The most central region or the region that was most representative of the entire surface area was used. The SEM (Jeol-Japan-JSM6380A, JAPAN) micrographs were examined to determine the type of surface presented. The enamel changes were classified as no or mild alteration, moderate alteration and severe altered surface. Regarding micro-morphology, the enamel surface of control groups showed smooth surface in general with some scattered clear scratches due to the polishing procedure. The specimens bleached in group 2 and group 3, represented areas of mild erosion. Bleaching with 38% Hydrogen Peroxide (HP) and 16% Carbamide Peroxide (CP) resulted in mild changes in surface micro-morphology of enamel.

  2. Effect of EDTA and phosphoric Acid pretreatment on the bonding effectiveness of self-etch adhesives to ground enamel.

    Science.gov (United States)

    Ibrahim, Ihab M; Elkassas, Dina W; Yousry, Mai M

    2010-10-01

    This in vitro study determined the effect of enamel pretreatment with phosphoric acid and ethylenediaminetetraacetic acid (EDTA) on the bond strength of strong, intermediary strong, and mild self-etching adhesive systems. Ninety sound human premolars were used. Resin composite cylinders were bonded to flat ground enamel surfaces using three self-etching adhesive systems: strong Adper Prompt L-Pop (pH=0.9-1.0), intermediary strong AdheSE (pH=1.6-1.7), and mild Frog (pH=2). Adhesive systems were applied either according to manufacturer instructions (control) or after pretreatment with either phosphoric acid or EDTA (n=10). After 24 hours, shear bond strength was tested using a universal testing machine at a cross-head speed of 0.5 mm/minute. Ultra-morphological characterization of the surface topography and resin/enamel interfaces as well as representative fractured enamel specimens were examined using scanning electron microscopy (SEM). Neither surface pretreatment statistically increased the mean shear bond strength values of either the strong or the intermediary strong self-etching adhesive systems. However, phosphoric acid pretreatment significantly increased the mean shear bond strength values of the mild self-etching adhesive system. SEM examination of enamel surface topography showed that phosphoric acid pretreatment deepened the same etching pattern of the strong and intermediary strong adhesive systems but converted the irregular etching pattern of the mild self-etching adhesive system to a regular etching pattern. SEM examination of the resin/enamel interface revealed that deepening of the etching pattern was consistent with increase in the length of resin tags. EDTA pretreatment had a negligible effect on ultra-morphological features. Use of phosphoric acid pretreatment can be beneficial with mild self-etching adhesive systems for bonding to enamel.

  3. Neuropsychological results after gamma knife radiosurgery for mesial temporal lobe epilepsy.

    Science.gov (United States)

    Vojtěch, Zdeněk; Krámská, Lenka; Malíková, Hana; Stará, Michaela; Liščák, Roman

    2015-01-01

    The aim of this study is to summarize our experience with neuropsychological changes after radiosurgical treatment for mesial temporal lobe epilepsy and subsequent surgery due to insufficient seizure control. Between November 1995 and May 1999, 14 patients underwent radiosurgical entorhinoamygdalohippocampectomy with a marginal dose of 18, 20 or 25 Gy to the 50% isodose. 9 of these patients subsequently underwent surgery. We compared Memory Quotients and Intelligence Quotients before and after the interventions. We found a slight, but nonsignificant decline in intelligence and memory quotients one year after GKRS. Two years after radiosurgery there were no significant changes in any of the quotients. After surgery, we found significant increase in Global and Visual MQ, (pmemory and intelligence performance after surgery. Epilepsy surgery after unsuccessful radiosurgery could lead to improvements in cognitive functions in patients with mesial temporal lobe epilepsy.

  4. A pediatric patient with refractory seizures and a mesial temporal lobe lesion

    Directory of Open Access Journals (Sweden)

    Marisa eMcGinley

    2015-06-01

    Full Text Available A 12 year old adolescent presented with refractory seizures and was found to have a mesial temporal lobe lesion. The patient underwent biopsy and was diagnosed with an arteriorvenous malformation. Supratentorial lesions in the pediatric population can have a large variety of underlying etiologies and it can challenging to differentiate on neuroimaging. In this report we discuss the key features on MRI of several neoplastic, vascular, and infectious processes that can aide in the diagnosis.

  5. Independent and Confluent Middle Mesial Root Canals in Mandibular First Molars: A Report of Four Cases

    Directory of Open Access Journals (Sweden)

    Mohanavelu Deepalakshmi

    2012-01-01

    Full Text Available Mandibular molars demonstrate considerable variations with respect to number of roots and root canals. The possibility of additional root canals should be considered even in teeth with a low frequency of abnormal root canal anatomy. This paper discusses the endodontic management of the rare anatomical complexity middle mesial canals in mandibular first molar and also serves to remind the clinicians that such anatomical variations should be taken into account during the endodontic treatment of the mandibular molars.

  6. Evaluation of the anatomical alterations of lower molars mesial root?s apical third

    OpenAIRE

    FRÖNER Izabel Cristina; IMPERADOR Cristina Aparecida; SOUZA Luiz Gustavo de

    1999-01-01

    The anatomical apex of the mesial root of the lower molars presents a morphological complexity related to the number and shape of the root canals as well as of the apical foramen and isthmus presence. The knowledge of the complexity of the endodontic system of the molar root area is essencial to select more carefully the best instrumentation and obturation technique, to obtain a more successful endodontic therapy.

  7. Evaluation of the anatomical alterations of lower molars mesial root?s apical third

    Directory of Open Access Journals (Sweden)

    FRÖNER Izabel Cristina

    1999-01-01

    Full Text Available The anatomical apex of the mesial root of the lower molars presents a morphological complexity related to the number and shape of the root canals as well as of the apical foramen and isthmus presence. The knowledge of the complexity of the endodontic system of the molar root area is essencial to select more carefully the best instrumentation and obturation technique, to obtain a more successful endodontic therapy.

  8. Carbamazepine reduces memory induced activation of mesial temporal lobe structures: a pharmacological fMRI-study

    Directory of Open Access Journals (Sweden)

    Okujava Michael

    2001-11-01

    Full Text Available Abstract Background and Purpose It is not known whether carbamazepine (CBZ; a drug widely used in neurology and psychiatry influences the blood oxygenation level dependent (BOLD contrast changes induced by neuronal activation and measured by functional MRI (fMRI. We aimed to investigate the influence of CBZ on memory induced activation of the mesial temporal lobes in patients with symptomatic temporal lobe epilepsy (TLE. Material and Methods Twenty-one individual patients with refractory symptomatic TLE with different CBZ serum levels and 20 healthy controls were studied using BOLD fMRI. Mesial temporal lobe (MTL activation was induced by a task that is based on the retrieval of individually familiar visuo-spatial knowledge. The extent of significant MTL fMRI activation was measured and correlated with the CBZ serum level. Results In TLE patients, the extent of significant fMRI activation over both MTL was negatively correlated to the CBZ serum level (Spearman r = -0.654, P Conclusions In TLE patients, carbamazepine reduces the fMRI-detectable changes within the mesial temporal lobes as induced by effortful memory retrieval. FMRI appears to be suitable to study the effects of chronic drug treatment in patients with epilepsy.

  9. EEG-fMRI Evaluation of Patients with Mesial Temporal Lobe Sclerosis

    Science.gov (United States)

    Avesani, Mirko; Giacopuzzi, Silvia; Bongiovanni, Luigi Giuseppe; Borelli, Paolo; Cerini, Roberto; Pozzi Mucelli, Roberto; Fiaschi, Antonio

    2014-01-01

    Summary This preliminary study sought more information on blood oxygen level dependent (BOLD) activation, especially contralateral temporal/extratemporal spread, during continuous EEG-fMRI recordings in four patients with mesial temporal sclerosis (MTS). In two patients, EEG showed unilateral focal activity during the EEG-fMRI session concordant with the interictal focus previously identified with standard and video-poly EEG. In the other two patients EEG demonstrated a contralateral diffusion of the irritative focus. In the third patient (with the most drug-resistant form and also extratemporal clinical signs), there was an extratemporal diffusion over frontal regions, ipsilateral to the irritative focus. fMRI analysis confirmed a single activation in the mesial temporal region in two patients whose EEG showed unilateral focal activity, while it demonstrated a bilateral activation in the mesial temporal regions in the other two patients. In the third patient, fMRI demonstrated an activation in the supplementary motxor area. This study confirms the most significant activation with a high firing rate of the irritative focus, but also suggests the importance of using new techniques (such as EEG-fMRI to examine cerebral blood flow) to identify the controlateral limbic activation, and any other extratemporal activations, possible causes of drug resistance in MTS that may require a more precise pre-surgical evaluation with invasive techniques. PMID:24571833

  10. Secondary bilateral synchrony due to fronto-mesial lesions: an invasive recording study

    Directory of Open Access Journals (Sweden)

    CUKIERT ARTHUR

    1999-01-01

    Full Text Available Frontal lobe epilepsies may present difficulties in focus localization in the pre-operative work-up for epilepsy surgery. This is specially true in patients with normal MRIs. We report on a 16 years-old girl that started with seizures by the age of 8 years. They were brief nocturnal episodes with automatisms such as bicycling and boxing. Seizure frequency ranged from 4-10 per night. Scalp EEG showed few right frontal convexity spiking and intense secondary bilateral syncrhony (SBS. High resolution MRI directed to the frontal lobes was normal. Ictal SPECT suggested a right fronto-lateral focus. Ictal video-EEG showed no focal onset. She was submitted to invasive recordings after subdural plates implantation. Electrodes covered all the frontal convexity and mesial surface bilaterally. Ictal recordings disclosed stereotyped seizures starting from the right mesial frontal. Using a high-resolution tool to measure intra and interhemispheric latencies, the timing and direction of seizure spread from the right fronto-mesial region were studied. Motor strip mapping was performed by means of electrical stimulation. She was submitted to a right frontal lobe resection, 1.5 cm ahead of the motor strip and has been seizure free since surgery (8 months. Pathological examination found a 4 mm area of cortical dysplasia. Invasive studies are needed to allow adequate localization in patients with non-localizatory non-invasive work-up and may lead to excellent results in relation to seizures after surgery.

  11. PREFACE: Aerodynamic sound Aerodynamic sound

    Science.gov (United States)

    Akishita, Sadao

    2010-02-01

    The modern theory of aerodynamic sound originates from Lighthill's two papers in 1952 and 1954, as is well known. I have heard that Lighthill was motivated in writing the papers by the jet-noise emitted by the newly commercialized jet-engined airplanes at that time. The technology of aerodynamic sound is destined for environmental problems. Therefore the theory should always be applied to newly emerged public nuisances. This issue of Fluid Dynamics Research (FDR) reflects problems of environmental sound in present Japanese technology. The Japanese community studying aerodynamic sound has held an annual symposium since 29 years ago when the late Professor S Kotake and Professor S Kaji of Teikyo University organized the symposium. Most of the Japanese authors in this issue are members of the annual symposium. I should note the contribution of the two professors cited above in establishing the Japanese community of aerodynamic sound research. It is my pleasure to present the publication in this issue of ten papers discussed at the annual symposium. I would like to express many thanks to the Editorial Board of FDR for giving us the chance to contribute these papers. We have a review paper by T Suzuki on the study of jet noise, which continues to be important nowadays, and is expected to reform the theoretical model of generating mechanisms. Professor M S Howe and R S McGowan contribute an analytical paper, a valuable study in today's fluid dynamics research. They apply hydrodynamics to solve the compressible flow generated in the vocal cords of the human body. Experimental study continues to be the main methodology in aerodynamic sound, and it is expected to explore new horizons. H Fujita's study on the Aeolian tone provides a new viewpoint on major, longstanding sound problems. The paper by M Nishimura and T Goto on textile fabrics describes new technology for the effective reduction of bluff-body noise. The paper by T Sueki et al also reports new technology for the

  12. Dental enamel defects, caries experience and oral health-related quality of life: a cohort study.

    Science.gov (United States)

    Arrow, P

    2017-06-01

    The impact of enamel defects of the first permanent molars on caries experience and child oral health-related quality of life was evaluated in a cohort study. Children who participated in a study of enamel defects of the first permanent molars 8 years earlier were invited for a follow-up assessment. Consenting children completed the Child Perception Questionnaire and the faces Modified Child Dental Anxiety Scale, and were examined by two calibrated examiners. ANOVA, Kruskal-Wallis, negative binomial and logistic regression were used for data analyses. One hundred and eleven children returned a completed questionnaire and 91 were clinically examined. Negative binomial regression found that oral health impacts were associated with gender (boys, risk ratio (RR) = 0.73, P = 0.03) and decayed, missing or filled permanent teeth (DMFT) (RR = 1.1, P = 0.04). The mean DMFT of children were sound (0.9, standard deviation (SD) = 1.4), diffuse defects (0.8, SD = 1.7), demarcated defects (1.5, SD = 1.4) and pit defects (1.3, SD = 2.3) (Kruskal-Wallis, P = 0.05). Logistic regression of first permanent molar caries found higher odds of caries experience with baseline primary tooth caries experience (odds ratio (OR) = 1.5, P = 0.01), the number of teeth affected by enamel defects (OR = 1.9, P = 0.05) and lower odds with the presence of diffuse enamel defects (OR = 0.1, P = 0.04). The presence of diffuse enamel defects was associated with lower odds of caries experience. © 2016 Australian Dental Association.

  13. Sound Visualisation

    OpenAIRE

    Dolenc, Peter

    2013-01-01

    This thesis contains a description of a construction of subwoofer case that has an extra functionality of being able to produce special visual effects and display visualizations that match the currently playing sound. For this reason, multiple lighting elements made out of LED (Light Emitting Diode) diodes were installed onto the subwoofer case. The lighting elements are controlled by dedicated software that was also developed. The software runs on STM32F4-Discovery evaluation board inside a ...

  14. Real-time near-IR imaging of laser-ablation crater evolution in dental enamel

    Science.gov (United States)

    Darling, Cynthia L.; Fried, Daniel

    2007-02-01

    We have shown that the enamel of the tooth is almost completely transparent near 1310-nm in the near-infrared and that near-IR (NIR) imaging has considerable potential for the optical discrimination of sound and demineralized tissue and for observing defects in the interior of the tooth. Lasers are now routinely used for many applications in dentistry including the ablation of dental caries. The objective of this study was to test the hypothesis that real-time NIR imaging can be used to monitor laser-ablation under varying conditions to assess peripheral thermal and transient-stress induced damage and to measure the rate and efficiency of ablation. Moreover, NIR imaging may have considerable potential for monitoring the removal of demineralized areas of the tooth during cavity preparations. Sound human tooth sections of approximately 3-mm thickness were irradiated by a CO II laser under varying conditions with and without a water spray. The incision area in the interior of each sample was imaged using a tungsten-halogen lamp with band-pass filter centered at 131--nm combined with an InGaAs focal plane array with a NIR zoom microscope in transillumination. Due to the high transparency of enamel at 1310-nm, laser-incisions were clearly visible to the dentin-enamel junction and crack formation, dehydration and irreversible thermal changes were observed during ablation. This study showed that there is great potential for near-IR imaging to monitor laser-ablation events in real-time to: assess safe laser operating parameters by imaging thermal and stress-induced damage, elaborate the mechanisms involved in ablation such as dehydration, and monitor the removal of demineralized enamel.

  15. An in vitro investigation of human enamel wear by restorative dental materials

    International Nuclear Information System (INIS)

    Adachi, L.K.; Saiki, M.; De Campos, T.N.

    2001-01-01

    A radiometric method was applied to asses enamel wear by another enamel and by restorative materials. The radioactive enamel was submitted to wear in a machine which allows sliding motion of an antagonistic surface in contact with the radioactive enamel. The enamel wear was evaluated by measuring the beta-activity of 32 P transferred to water from this irradiated tooth. Results obtained indicated that dental porcelains cause pronounced enamel wear when compared with that provoked by another natural enamel or by resin materials. Resin materials caused less enamel wear than another natural enamel. Vickers microhardness data obtained for antagonistic materials showed a correlation with the wear caused to the enamel. (author)

  16. Diffusion of fluoride in bovine enamel

    International Nuclear Information System (INIS)

    Flim, G.J.; Arends, J.; Kolar, Z.

    1976-01-01

    The uptake of 18 F and the penetration of both F and 18 F in bovine enamel was investigated. Sodium fluoride solutions buffered at pH 7 were employed. The uptake of 18 F was measured by a method described by R. Duckworth and M. Braden, Archs. Oral. Biol., 12(1967), pp. 217-230. The penetration concentration profiles of fluoride (F, 18 F) in the enamel were measured by a sectioning technique. The 18 F uptake in enamel was proportional to approximately tsup(3/4); t being the uptake time. The 18 F concentration as a function of the position in the enamel can be described by: c*(x,t) = c 0 *(t)exp[-α*(t)x]. After correction for the initial fluoride concentration in enamel, for unlabelled fluoride the same dependency is obtained. A model based on simultaneous diffusion and chemical reaction in the pores and diffusion into the hydroxyapatite crystallites will be presented. The results show that diffusion coefficients of the pores are approximately equal to 10 -10 cm 2 s -1 and in the apatite crystallites approximately equal to 10 -17 cm 2 s -1 . The limitations and the approximations of the model are discussed

  17. The fracture behaviour of dental enamel.

    Science.gov (United States)

    Bechtle, Sabine; Habelitz, Stefan; Klocke, Arndt; Fett, Theo; Schneider, Gerold A

    2010-01-01

    Enamel is the hardest tissue in the human body covering the crowns of teeth. Whereas the underlying dental material dentin is very well characterized in terms of mechanical and fracture properties, available data for enamel are quite limited and are apart from the most recent investigation mainly based on indentation studies. Within the current study, stable crack-growth experiments in bovine enamel have been performed, to measure fracture resistance curves for enamel. Single edge notched bending specimens (SENB) prepared out of bovine incisors were tested in 3-point bending and subsequently analysed using optical and environmental scanning electron microscopy. Cracks propagated primarily within the protein-rich rod sheaths and crack propagation occurred under an inclined angle to initial notch direction not only due to enamel rod and hydroxyapatite crystallite orientation but potentially also due to protein shearing. Determined mode I fracture resistance curves ranged from 0.8-1.5 MPa*m(1/2) at the beginning of crack propagation up to 4.4 MPa*m(1/2) at 500 microm crack extension; corresponding mode II values ranged from 0.3 to 1.5 MPa*m(1/2).

  18. Differentiation of cryptogenic lateral from mesial temporal lobe epilepsy using regional asymmetric index of F-18-FDG PET

    International Nuclear Information System (INIS)

    Song, H. C.; Lee, D. S.; Lee, S. K.; Jeong, J. M.; Jeong, Z. K.; Lee, M. C.; Ko, C. S.

    1997-01-01

    We tried to find the possibility of utilization of F-18-FDG PET to differentiate lateral (neocortical) from mesial temporal lobe epilepsy(TLE) if we adopted quantitative comparison of regional metabolic activities using asymmetric index. We studied 22 pathologically proven mesial TLE(group C in Figure), and 27 lateral TLE patients. Lateral TLE patients were normal on MR(cryptogenic: 15; group A) or had structural lesions (12: group B). Asymmetric index (AI) was calculated as (ipsilateral -contralateral) / (ipsilateral + contralateral ) x 200. AI of medial lobe of cryptogenic lateral TLE was not decreased (-4.66.2, > 0.05) and AI of medial lobe of cryptogenic lateral TLE was not decreased (-4.66.2, >0.05) and AI of lateral lobe was decreased (-13.68.9). AI of medial and lateral lobes of mesial TLE was decreased (-3.44.7 and -16.58.9, respectively). AI of medial lobe of lesional lateral TLE was -7.39.1 (p<0.05 compared with mesial TEL). It was evident that lateral lobe of lesional lateral TLE had metabolic defect or decrease (AI: -21.410.4). While we could not find difference of metabolic activity in lateral temporal lobes between cryptogenic lateral TLE and mesial TLE patients, the difference of metabolic activity was significant in medial temporal lobes which was revealed by AI quantitation. An AI value larger than -10 (cutoff: AI) predicted positively for lateral TLE(PPV:80%) and negatively for mesial TLE(NPV:77%). Asymmetry of metabolic activity in medial and not in lateral lobe of temporal lobe could give hints about whether the epileptogenic zones were mesial or lateral

  19. Enamel tissue engineering using subcultured enamel organ epithelial cells in combination with dental pulp cells.

    Science.gov (United States)

    Honda, Masaki J; Shinmura, Yuka; Shinohara, Yoshinori

    2009-01-01

    We describe a strategy for the in vitro engineering of enamel tissue using a novel technique for culturing enamel organ epithelial (EOE) cells isolated from the enamel organ using 3T3-J2 cells as a feeder layer. These subcultured EOE cells retain the capacity to produce enamel structures over a period of extended culture. In brief, enamel organs from 6-month-old porcine third molars were dissociated into single cells and subcultured on 3T3-J2 feeder cell layers. These subcultured EOE cells were then seeded onto a collagen sponge in combination with primary dental pulp cells isolated at an early stage of crown formation, and these constructs were transplanted into athymic rats. After 4 weeks, complex enamel-dentin structures were detected in the implants. These results show that our culture technique maintained ameloblast lineage cells that were able to produce enamel in vivo. This novel subculture technique provides an important tool for tooth tissue engineering. Copyright 2008 S. Karger AG, Basel.

  20. Morphology of the cemento-enamel junction in premolar teeth.

    Science.gov (United States)

    Arambawatta, Kapila; Peiris, Roshan; Nanayakkara, Deepthi

    2009-12-01

    The present study attempted to describe the distribution of the mineralized tissues that compose the cemento-enamel junction, with respect to both the different types of permanent premolars of males and females and the various surfaces of individual teeth. The cervical region of ground sections of 67 premolars that had been extracted for orthodontic reasons were analyzed using transmitted light microscopy to identify which of the following tissue interrelationships was present at the cemento-enamel junction: cementum overlapping enamel; enamel overlapping cementum; edge-to-edge relationship between cementum and enamel; or the presence of gaps between the enamel and cementum with exposed dentin. An edge-to-edge interrelation between root cementum and enamel was predominant (55.1%). In approximately one-third of the sample, gaps between cementum and enamel with exposed dentin were observed. Cementum overlapping enamel was less prevalent than previously reported, and enamel overlapping cementum was seen in a very small proportion of the sample. In any one tooth, the distribution of mineralized tissues at the cemento-enamel junction was irregular and unpredictable. The frequency of gaps between enamel and cementum with exposure of dentin was higher than previously reported, which suggests that this region is fragile and strongly predisposed to pathological changes. Hence, this region should be protected and carefully managed during routine clinical procedures such as dental bleaching, orthodontic treatment, and placement of restorative materials.

  1. Finite element analysis of the cyclic indentation of bilayer enamel

    International Nuclear Information System (INIS)

    Jia, Yunfei; Xuan, Fu-zhen; Chen, Xiaoping; Yang, Fuqian

    2014-01-01

    Tooth enamel is often subjected to repeated contact and often experiences contact deformation in daily life. The mechanical strength of the enamel determines the biofunctionality of the tooth. Considering the variation of the rod arrangement in outer and inner enamel, we approximate enamel as a bilayer structure and perform finite element analysis of the cyclic indentation of the bilayer structure, to mimic the repeated contact of enamel during mastication. The dynamic deformation behaviour of both the inner enamel and the bilayer enamel is examined. The material parameters of the inner and outer enamel used in the analysis are obtained by fitting the finite element results with the experimental nanoindentation results. The penetration depth per cycle at the quasi-steady state is used to describe the depth propagation speed, which exhibits a two-stage power-law dependence on the maximum indentation load and the amplitude of the cyclic load, respectively. The continuous penetration of the indenter reflects the propagation of the plastic zone during cyclic indentation, which is related to the energy dissipation. The outer enamel serves as a protective layer due to its great resistance to contact deformation in comparison to the inner enamel. The larger equivalent plastic strain and lower stresses in the inner enamel during cyclic indentation, as calculated from the finite element analysis, indicate better crack/fracture resistance of the inner enamel. (paper)

  2. Finite element analysis of the cyclic indentation of bilayer enamel

    Science.gov (United States)

    Jia, Yunfei; Xuan, Fu-zhen; Chen, Xiaoping; Yang, Fuqian

    2014-04-01

    Tooth enamel is often subjected to repeated contact and often experiences contact deformation in daily life. The mechanical strength of the enamel determines the biofunctionality of the tooth. Considering the variation of the rod arrangement in outer and inner enamel, we approximate enamel as a bilayer structure and perform finite element analysis of the cyclic indentation of the bilayer structure, to mimic the repeated contact of enamel during mastication. The dynamic deformation behaviour of both the inner enamel and the bilayer enamel is examined. The material parameters of the inner and outer enamel used in the analysis are obtained by fitting the finite element results with the experimental nanoindentation results. The penetration depth per cycle at the quasi-steady state is used to describe the depth propagation speed, which exhibits a two-stage power-law dependence on the maximum indentation load and the amplitude of the cyclic load, respectively. The continuous penetration of the indenter reflects the propagation of the plastic zone during cyclic indentation, which is related to the energy dissipation. The outer enamel serves as a protective layer due to its great resistance to contact deformation in comparison to the inner enamel. The larger equivalent plastic strain and lower stresses in the inner enamel during cyclic indentation, as calculated from the finite element analysis, indicate better crack/fracture resistance of the inner enamel.

  3. Evaluation of dental enamel caries assessment using Quantitative Light Induced Fluorescence and Optical Coherence Tomography.

    Science.gov (United States)

    Maia, Ana Marly Araújo; de Freitas, Anderson Zanardi; de L Campello, Sergio; Gomes, Anderson Stevens Leônidas; Karlsson, Lena

    2016-06-01

    An in vitro study of morphological alterations between sound dental structure and artificially induced white spot lesions in human teeth, was performed through the loss of fluorescence by Quantitative Light-Induced Fluorescence (QLF) and the alterations of the light attenuation coefficient by Optical Coherence Tomography (OCT). To analyze the OCT images using a commercially available system, a special algorithm was applied, whereas the QLF images were analyzed using the software available in the commercial system employed. When analyzing the sound region against white spot lesions region by QLF, a reduction in the fluorescence intensity was observed, whilst an increase of light attenuation by the OCT system occurred. Comparison of the percentage of alteration between optical properties of sound and artificial enamel caries regions showed that OCT processed images through the attenuation of light enhanced the tooth optical alterations more than fluorescence detected by QLF System. QLF versus OCT imaging of enamel caries: a photonics assessment. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Uso da sequência FLAIR-EPI na análise da esclerose mesial temporal EPI-FLAIR sequence in the evaluation of mesial temporal sclerosis

    Directory of Open Access Journals (Sweden)

    Marcos Alberto da Costa Machado Júnior

    2001-06-01

    Full Text Available O objetivo deste estudo é analisar as alterações morfológicas e de intensidade de sinal das regiões hipocampais em pacientes, com epilepsia temporal fármaco-resistente. Para tal, estudamos 8 pacientes com esclerose mesial temporal, utilizando aparelhagem de RM de 1,5T, com sequências Spin Eco - SE, Fast Spin Eco - FSE, Fluid Atenuation Inversion Recovery, com Eco Planar Imaging - FLAIR-EPI. Observamos a superioridade da sequência FLAIR na detecção do aumento da intensidade de sinal da região hipocampal, particularmente com cortes coronais, em relação às sequências SE e FSE, com a vantagem de ser uma técnica de rápida execução. A sequência STIR evidenciou adelgaçamento da cortical do hipocampo, na metade dos casos que apresentavam alteração de sinal.The purpose of this study is to evaluate morpholologycal and signal intensity changes in the hippocampus in patients with medically intractable temporal lobe epilepsy. We studied 8 patients with mesial temporal sclerosis using a 1.5 -T MR and the following sequences Spin Eco- SE, Fast Spin Echo- FSE, Fluid Atenuation Inversion Recovery Echo Planar Imaging - FLAIR-EPI. We noticed a sensitive increase signal intensity on FLAIR- EPI sequences, particularly, in coronal images, than on SE and FSE sequences. The STIR sequence showed a cortical hippocampus atrophy in half of the cases, in whom signal abnormalities were present.

  5. Enamel alteration following tooth bleaching and remineralization.

    Science.gov (United States)

    Coceska, Emilija; Gjorgievska, Elizabeta; Coleman, Nichola J; Gabric, Dragana; Slipper, Ian J; Stevanovic, Marija; Nicholson, John W

    2016-06-01

    The purpose of this study was to compare the effects of professional tooth whitening agents containing highly concentrated hydrogen peroxide (with and without laser activation), on the enamel surface; and the potential of four different toothpastes to remineralize any alterations. The study was performed on 50 human molars, divided in two groups: treated with Opalescence(®) Boost and Mirawhite(®) Laser Bleaching. Furthermore, each group was divided into five subgroups, a control one and 4 subgroups remineralized with: Mirasensitive(®) hap+, Mirawhite(®) Gelleѐ, GC Tooth Mousse™ and Mirafluor(®) C. The samples were analysed by SEM/3D-SEM-micrographs, SEM/EDX-qualitative analysis and SEM/EDX-semiquantitative analysis. The microphotographs show that both types of bleaching cause alterations: emphasized perikymata, erosions, loss of interprizmatic substance; the laser treatment is more aggressive and loss of integrity of the enamel is determined by shearing off the enamel rods. In all samples undergoing remineralization deposits were observed, those of toothpastes based on calcium phosphate technologies seem to merge with each other and cover almost the entire surface of the enamel. Loss of integrity and minerals were detected only in the line-scans of the sample remineralized with GC Tooth Mousse™. The semiquantitative EDX analysis of individual elements in the surface layer of the enamel indicates that during tooth-bleaching with HP statistically significant loss of Na and Mg occurs, whereas the bleaching in combination with a laser leads to statistically significant loss of Ca and P. The results undoubtedly confirm that teeth whitening procedures lead to enamel alterations. In this context, it must be noted that laser bleaching is more aggressive for dental substances. However, these changes are reversible and can be repaired by application of remineralization toothpastes. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  6. Thermal induced EPR signals in tooth enamel

    International Nuclear Information System (INIS)

    Fattibene, P.; Aragno, D.; Onori, S.; Pressello, M.C.

    2000-01-01

    Electron paramagnetic resonance (EPR) spectroscopy was used to detect the effects of temperature on powdered human tooth enamel, not irradiated in the laboratory. Samples were heated at temperature between 350 and 450, at 600 and at 1000 deg. C, for different heating times, between 6 min and 39 h. Changes in the EPR spectra were detected, with the formation of new signals. Possible correlation between the changes in EPR spectra and modifications in the enamel and in the mineral phase of bone detected with other techniques is discussed. The implications for dosimetric applications of signals induced by overheating due to mechanical friction during sample preparation are underlined

  7. Bond strength and interfacial morphology of orthodontic brackets bonded to eroded enamel treated with calcium silicate-sodium phosphate salts or resin infiltration.

    Science.gov (United States)

    Costenoble, Aline; Vennat, Elsa; Attal, Jean-Pierre; Dursun, Elisabeth

    2016-11-01

     To investigate the shear bond strength (SBS) of orthodontic brackets bonded to eroded enamel treated with preventive approaches and to examine the enamel/bracket interfaces.  Ninety-one brackets were bonded to seven groups of enamel samples: sound; eroded; eroded+treated with calcium silicate-sodium phosphate salts (CSP); eroded+infiltrated by ICON ® ; eroded+infiltrated by ICON ® and brackets bonded with 1-month delay; eroded+infiltrated by an experimental resin; and eroded+infiltrated by an experimental resin and brackets bonded with 1-month delay. For each group, 12 samples were tested in SBS and bond failure was assessed with the adhesive remnant index (ARI); one sample was examined using scanning electron microscopy (SEM).  Samples treated with CSP or infiltration showed no significant differences in SBS values with sound samples. Infiltrated samples followed by a delayed bonding showed lower SBS values. All of the values remained acceptable. The ARI scores were significantly higher for sound enamel, eroded, and treated with CSP groups than for all infiltrated samples. SEM examinations corroborated the findings.  Using CSP or resin infiltration before orthodontic bonding does not jeopardize the bonding quality. The orthodontic bonding should be performed shortly after the resin infiltration.

  8. In Situ analysis of CO2 laser irradiation on controlling progression of erosive lesions on dental enamel.

    Science.gov (United States)

    Lepri, Taísa Penazzo; Scatolin, Renata Siqueira; Colucci, Vivian; De Alexandria, Adílis Kalina; Maia, Lucianne Cople; Turssi, Cecília Pedroso; Corona, Silmara Aparecida Milori

    2014-08-01

    The present study aimed to evaluate in situ the effect of CO2 laser irradiation to control the progression of enamel erosive lesions. Fifty-six slabs of bovine incisors enamel (5 × 3 × 2.5 mm(3) ) were divided in four distinct areas: (1) sound (reference area), (2) initial erosion, (3) treatment (irradiated or nonirradiated with CO2 laser), (4) final erosion (after in situ phase). The initial erosive challenge was performed with 1% citric acid (pH = 2.3), for 5 min, 2×/day, for 2 days. The slabs were divided in two groups according to surface treatment: irradiated with CO2 laser (λ = 10.6 µm; 0.5 W) and nonirradiate. After a 2-day lead-in period, 14 volunteers wore an intraoral palatal appliance containing two slabs (irradiated and nonirradiated), in two intraoral phases of 5 days each. Following a cross-over design during the first intraoral phase, half of the volunteers immersed the appliance in 100 mL of citric acid for 5 min, 3×/day, while other half of the volunteers used deionized water (control). The volunteers were crossed over in the second phase. Enamel wear was determined by an optical 3D profilometer. Three-way ANOVA for repeated measures revealed that there was no significant interaction between erosive challenge and CO2 laser irradiation (P = 0.419). Erosive challenge significantly increased enamel wear (P = 0.001), regardless whether or not CO2 laser irradiation was performed. There was no difference in enamel wear between specimens CO2 -laser irradiated and non-irradiated (P = 0.513). Under intraoral conditions, CO2 laser irradiation did not control the progression of erosive lesions in enamel caused by citric acid. © 2014 Wiley Periodicals, Inc.

  9. Potential of CO2 lasers (10.6 µm associated with fluorides in inhibiting human enamel erosion

    Directory of Open Access Journals (Sweden)

    Thayanne Monteiro RAMOS-OLIVEIRA

    2014-01-01

    Full Text Available This in vitro study aimed to investigate the potential of CO2 lasers associated with different fluoride agents in inhibiting enamel erosion. Human enamel samples were randomly divided into 9 groups (n = 12: G1-eroded enamel; G2-APF gel; G3-AmF/NaF gel; G4-AmF/SnF2 solution; G5-CO2 laser (λ = 10.6 µm+APF gel; G6-CO2 laser+AmF/NaF gel; G7-CO2laser+AmF/SnF2solution; G8-CO2 laser; and G9-sound enamel. The CO2 laser parameters were: 0.45 J/cm2; 6 μs; and 128 Hz. After surface treatment, the samples (except from G9 were immersed in 1% citric acid (pH 4.0, 3 min. Surface microhardness was measured at baseline and after surface softening. The data were statistically analyzed by one-way ANOVA and Tukey’s tests (p < 0.05. G2 (407.6 ± 37.3 presented the highest mean SMH after softening, followed by G3 (407.5 ± 29.8 and G5 (399.7 ± 32.9. Within the fluoride-treated groups, G4 (309.0 ± 24.4 had a significantly lower mean SMH than G3 and G2, which were statistically similar to each other. AmF/NaF and APF application showed potential to protect and control erosion progression in dental enamel, and CO2 laser irradiation at 0.45J/cm2 did not influence its efficacy. CO2 laser irradiation alone under the same conditions could also significantly decrease enamel erosive mineral loss, although at lower levels.

  10. Laser interstitial thermal therapy for medically intractable mesial temporal lobe epilepsy.

    Science.gov (United States)

    Kang, Joon Y; Wu, Chengyuan; Tracy, Joseph; Lorenzo, Matthew; Evans, James; Nei, Maromi; Skidmore, Christopher; Mintzer, Scott; Sharan, Ashwini D; Sperling, Michael R

    2016-02-01

    To describe mesial temporal lobe ablated volumes, verbal memory, and surgical outcomes in patients with medically intractable mesial temporal lobe epilepsy (mTLE) treated with magnetic resonance imaging (MRI)-guided stereotactic laser interstitial thermal therapy (LiTT). We prospectively tracked seizure outcome in 20 patients at Thomas Jefferson University Hospital with drug-resistant mTLE who underwent MRI-guided LiTT from December 2011 to December 2014. Surgical outcome was assessed at 6 months, 1 year, 2 years, and at the most recent visit. Volume-based analysis of ablated mesial temporal structures was conducted in 17 patients with mesial temporal sclerosis (MTS) and results were compared between the seizure-free and not seizure-free groups. Following LiTT, proportions of patients who were free of seizures impairing consciousness (including those with auras only) are as follows: 8 of 15 patients (53%, 95% confidence interval [CI] 30.1-75.2%) after 6 months, 4 of 11 patients (36.4%, 95% CI 14.9-64.8%) after 1 year, 3 of 5 patients (60%, 95% CI 22.9-88.4%) at 2-year follow-up. Median follow-up was 13.4 months after LiTT (range 1.3 months to 3.2 years). Seizure outcome after LiTT suggests an all or none response. Four patients had anterior temporal lobectomy (ATL) after LiTT; three are seizure-free. There were no differences in total ablated volume of the amygdalohippocampus complex or individual volumes of hippocampus, amygdala, entorhinal cortex, parahippocampal gyrus, and fusiform gyrus between seizure-free and non-seizure-free patients. Contextual verbal memory performance was preserved after LiTT, although decline in noncontextual memory task scores were noted. We conclude that MRI-guided stereotactic LiTT is a safe alternative to ATL in patients with medically intractable mTLE. Individualized assessment is warranted to determine whether the reduced odds of seizure freedom are worth the reduction in risk, discomfort, and recovery time. Larger prospective

  11. Radiosurgery for Medial Temporal Lobe Epilepsy Resulting from Mesial Temporal Sclerosis.

    Science.gov (United States)

    Gianaris, Thomas; Witt, Thomas; Barbaro, Nicholas M

    2016-01-01

    Medial temporal lobe epilepsy associated with mesial temporal sclerosis (MTS) is perhaps the most well-defined epilepsy syndrome that is responsive to structural interventions such as surgery. Several minimally invasive techniques have arisen that provide additional options for the treatment of MTS while potentially avoiding many of open surgery's associated risks. By evading these risks, they also open up treatment options to patients who otherwise are poor surgical candidates. Radiosurgery is one of the most intensively studied of these alternatives and has found a growing role in the treatment of medial temporal lobe epilepsy. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Endodontic treatment of a mandibular first molar with three mesial canals and broken instrument removal.

    Science.gov (United States)

    Faramarzi, Farhad; Fakhri, Hamidreza; Fakri, Hamidreza; Javaheri, Homan H

    2010-04-01

    To succeed in any dental procedure, the clinician's awareness of the patient's dental anatomy and its variations is crucial. In endodontic therapy, obtaining full information about the root canals' variations can affect the outcome substantially. This case report presents the endodontic treatment of a mandibular first molar exhibiting three mesial root canals with 4 mm of a separated K-file in the coronal third of the mesiolingual canal on an 18-year-old female patient. This case demonstrates the importance of locating additional canals in any roots undergoing endodontic treatment and how the clinician's awareness of aberrant internal anatomy may change the treatment results.

  13. Evaluation of the anatomical alterations of lower molars mesial root’s apical third

    OpenAIRE

    FRÖNER, Izabel Cristina; IMPERADOR, Cristina Aparecida; SOUZA, Luiz Gustavo de

    1999-01-01

    The anatomical apex of the mesial root of the lower molars presents a morphological complexity related to the number and shape of the root canals as well as of the apical foramen and isthmus presence. The knowledge of the complexity of the endodontic system of the molar root area is essencial to select more carefully the best instrumentation and obturation technique, to obtain a more successful endodontic therapy. A presente pesquisa analisa in vitro as alterações anatômicas dos 4 mm apic...

  14. Brain-responsive neurostimulation in patients with medically intractable mesial temporal lobe epilepsy.

    Science.gov (United States)

    Geller, Eric B; Skarpaas, Tara L; Gross, Robert E; Goodman, Robert R; Barkley, Gregory L; Bazil, Carl W; Berg, Michael J; Bergey, Gregory K; Cash, Sydney S; Cole, Andrew J; Duckrow, Robert B; Edwards, Jonathan C; Eisenschenk, Stephan; Fessler, James; Fountain, Nathan B; Goldman, Alicia M; Gwinn, Ryder P; Heck, Christianne; Herekar, Aamar; Hirsch, Lawrence J; Jobst, Barbara C; King-Stephens, David; Labar, Douglas R; Leiphart, James W; Marsh, W Richard; Meador, Kimford J; Mizrahi, Eli M; Murro, Anthony M; Nair, Dileep R; Noe, Katherine H; Park, Yong D; Rutecki, Paul A; Salanova, Vicenta; Sheth, Raj D; Shields, Donald C; Skidmore, Christopher; Smith, Michael C; Spencer, David C; Srinivasan, Shraddha; Tatum, William; Van Ness, Paul C; Vossler, David G; Wharen, Robert E; Worrell, Gregory A; Yoshor, Daniel; Zimmerman, Richard S; Cicora, Kathy; Sun, Felice T; Morrell, Martha J

    2017-06-01

    Evaluate the seizure-reduction response and safety of mesial temporal lobe (MTL) brain-responsive stimulation in adults with medically intractable partial-onset seizures of mesial temporal lobe origin. Subjects with mesial temporal lobe epilepsy (MTLE) were identified from prospective clinical trials of a brain-responsive neurostimulator (RNS System, NeuroPace). The seizure reduction over years 2-6 postimplantation was calculated by assessing the seizure frequency compared to a preimplantation baseline. Safety was assessed based on reported adverse events. There were 111 subjects with MTLE; 72% of subjects had bilateral MTL onsets and 28% had unilateral onsets. Subjects had one to four leads placed; only two leads could be connected to the device. Seventy-six subjects had depth leads only, 29 had both depth and strip leads, and 6 had only strip leads. The mean follow-up was 6.1 ± (standard deviation) 2.2 years. The median percent seizure reduction was 70% (last observation carried forward). Twenty-nine percent of subjects experienced at least one seizure-free period of 6 months or longer, and 15% experienced at least one seizure-free period of 1 year or longer. There was no difference in seizure reduction in subjects with and without mesial temporal sclerosis (MTS), bilateral MTL onsets, prior resection, prior intracranial monitoring, and prior vagus nerve stimulation. In addition, seizure reduction was not dependent on the location of depth leads relative to the hippocampus. The most frequent serious device-related adverse event was soft tissue implant-site infection (overall rate, including events categorized as device-related, uncertain, or not device-related: 0.03 per implant year, which is not greater than with other neurostimulation devices). Brain-responsive stimulation represents a safe and effective treatment option for patients with medically intractable epilepsy, including patients with unilateral or bilateral MTLE who are not candidates for

  15. Sound knowledge

    DEFF Research Database (Denmark)

    Kauffmann, Lene Teglhus

    as knowledge based on reflexive practices. I chose ‘health promotion’ as the field for my research as it utilises knowledge produced in several research disciplines, among these both quantitative and qualitative. I mapped out the institutions, actors, events, and documents that constituted the field of health...... of the research is to investigate what is considered to ‘work as evidence’ in health promotion and how the ‘evidence discourse’ influences social practices in policymaking and in research. From investigating knowledge practices in the field of health promotion, I develop the concept of sound knowledge...... result of a rigorous and standardized research method. However, this anthropological analysis shows that evidence and evidence-based is a hegemonic ‘way of knowing’ that sometimes transposes everyday reasoning into an epistemological form. However, the empirical material shows a variety of understandings...

  16. Retrospective individual dosimetry using EPR of tooth enamel

    International Nuclear Information System (INIS)

    Skvortzo, V.; Ivannikov, A.; Stepanenko, V.; Wieser, A.; Bougai, A.; Brick, A.; Chumak, V.; Radchuk, V.; Repin, V.; Kirilov, V.

    1996-01-01

    The results of joint investigations (in the framework of ECP-10 program) aimed on the improvement of the sensitivity and accuracy of the procedure of dose measurement using tooth enamel EPR spectroscopy are presented. It is shown, what the sensitivity of method may be increased using special physical-chemical procedure of the enamel samples treatment, which leads to the reducing of EPR signal of organic components in enamel. Tooth diseases may have an effect on radiation sensitivity of enamel. On the basis of statistical analysis of the results of more then 2000 tooth enamel samples measurements it was shown, what tooth enamel EPR spectroscopy gives opportunity to register contribution into total dose, which is caused by natural environmental radiation and by radioactive contamination. EPR response of enamel to ultraviolet exposure is investigated and possible influences to EPR dosimetry is discussed. The correction factors for EPR dosimetry in real radiation fields are estimated

  17. Size dependent elastic modulus and mechanical resilience of dental enamel.

    Science.gov (United States)

    O'Brien, Simona; Shaw, Jeremy; Zhao, Xiaoli; Abbott, Paul V; Munroe, Paul; Xu, Jiang; Habibi, Daryoush; Xie, Zonghan

    2014-03-21

    Human tooth enamel exhibits a unique microstructure able to sustain repeated mechanical loading during dental function. Although notable advances have been made towards understanding the mechanical characteristics of enamel, challenges remain in the testing and interpretation of its mechanical properties. For example, enamel was often tested under dry conditions, significantly different from its native environment. In addition, constant load, rather than indentation depth, has been used when mapping the mechanical properties of enamel. In this work, tooth specimens are prepared under hydrated conditions and their stiffnesses are measured by depth control across the thickness of enamel. Crystal arrangement is postulated, among other factors, to be responsible for the size dependent indentation modulus of enamel. Supported by a simple structure model, effective crystal orientation angle is calculated and found to facilitate shear sliding in enamel under mechanical contact. In doing so, the stress build-up is eased and structural integrity is maintained. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Targeted p120-catenin ablation disrupts dental enamel development

    DEFF Research Database (Denmark)

    Bartlett, John D; Dobeck, Justine M; Tye, Coralee E

    2010-01-01

    Dental enamel development occurs in stages. The ameloblast cell layer is adjacent to, and is responsible for, enamel formation. When rodent pre-ameloblasts become tall columnar secretory-stage ameloblasts, they secrete enamel matrix proteins, and the ameloblasts start moving in rows that slide...... by one another. This movement is necessary to form the characteristic decussating enamel prism pattern. Thus, a dynamic system of intercellular interactions is required for proper enamel development. Cadherins are components of the adherens junction (AJ), and they span the cell membrane to mediate...... attachment to adjacent cells. p120 stabilizes cadherins by preventing their internalization and degradation. So, we asked if p120-mediated cadherin stability is important for dental enamel formation. Targeted p120 ablation in the mouse enamel organ had a striking effect. Secretory stage ameloblasts detached...

  19. Ceramic-like wear behaviour of human dental enamel.

    Science.gov (United States)

    Arsecularatne, J A; Hoffman, M

    2012-04-01

    This paper reports a transmission electron microscopy (TEM) analysis of subsurfaces of enamel specimens following in vitro reciprocating wear tests with an enamel cusp sliding on a flat enamel specimen under hydrated conditions. The obtained results show that crack formation occurred in the wear scar subsurface. The path followed by these cracks seems to be dictated either by the histological structure of enamel or by the contact stress field. Moreover, the analysis of a set of enamel wear results obtained from the literature and application of fracture-based models, originally developed for ceramics, correlate well, confirming the similar wear processes taking place in these materials. This analysis also reveals a marked influence of coefficient of friction on the enamel wear rate: for a higher coefficient of friction value, enamel wear can be severe even under forces generated during normal operation of teeth. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Regulated fracture in tooth enamel: a nanotechnological strategy from nature.

    Science.gov (United States)

    Ghadimi, Elnaz; Eimar, Hazem; Song, Jun; Marelli, Benedetto; Ciobanu, Ovidiu; Abdallah, Mohamed-Nur; Stähli, Christoph; Nazhat, Showan N; Vali, Hojatollah; Tamimi, Faleh

    2014-07-18

    Tooth enamel is a very brittle material; however it has the ability to sustain cracks without suffering catastrophic failure throughout the lifetime of mechanical function. We propose that the nanostructure of enamel can play a significant role in defining its unique mechanical properties. Accordingly we analyzed the nanostructure and chemical composition of a group of teeth, and correlated it with the crack resistance of the same teeth. Here we show how the dimensions of apatite nanocrystals in enamel can affect its resistance to crack propagation. We conclude that the aspect ratio of apatite nanocrystals in enamel determines its resistance to crack propagation. According to this finding, we proposed a new model based on the Hall-Petch theory that accurately predicts crack propagation in enamel. Our new biomechanical model of enamel is the first model that can successfully explain the observed variations in the behavior of crack propagation of tooth enamel among different humans. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Towards enamel biomimetics: Structure, mechanical properties and biomineralization of dental enamel

    Science.gov (United States)

    Fong, Hanson Kwok

    Dental enamel is the most mineralized tissue in the human body. This bioceramic, composed largely of hydroxyapatite (HAp), is also one of the most durable tissues despite a lifetime of masticatory loading and bacterial attack. The biosynthesis of enamel, which occurs in physiological conditions is a complex orchestration of protein assembly and mineral formation. The resulting product is the hardest tissue in the vertebrate body with the longest and most organized arrangement of hydroxyapatite crystals known to biomineralizing systems. Detail understanding of the structure of enamel in relationship to its mechanical function and the biomineralization process will provide a framework for enamel regeneration as well as potential lessons in the design of engineering materials. The objective of this study, therefore, is twofold: (1) establish the structure-function relationship of enamel as well as the dentine-enamel junction (DEJ) and (2) determine the effect of proteins on the enamel biomineralization process. A hierarchy in the enamel structure was established by means of various microscopy techniques (e.g. SEM, TEM, AFM). Mechanical properties (hardness and elastic modulus) associated with the microstructural features were also determined by nanoindentation. Furthermore, the DEJ was found to have a width in the range of micrometers to 10s of micrometers with continuous change in structure and mechanical properties. Indentation tests and contact fatigue tests using a spherical indenter have revealed that the structural features in the enamel and the DEJ played important roles in containing crack propagation emanating from the enamel tissue. To further understand the effect of this protein on the biominerailzation process, we have studied genetically engineered animals that express altered amelogenin which lack the known self-assembly properties. This in vivo study has revealed that, without the proper self-assembly of the amelogenin protein as demonstrated by the

  2. Helium ion microscopy of enamel crystallites and extracellular tooth enamel matrix.

    Science.gov (United States)

    Bidlack, Felicitas B; Huynh, Chuong; Marshman, Jeffrey; Goetze, Bernhard

    2014-01-01

    An unresolved problem in tooth enamel studies has been to analyze simultaneously and with sufficient spatial resolution both mineral and organic phases in their three dimensional (3D) organization in a given specimen. This study aims to address this need using high-resolution imaging to analyze the 3D structural organization of the enamel matrix, especially amelogenin, in relation to forming enamel crystals. Chemically fixed hemi-mandibles from wild type mice were embedded in LR White acrylic resin, polished and briefly etched to expose the organic matrix in developing tooth enamel. Full-length amelogenin was labeled with specific antibodies and 10 nm immuno-gold. This allowed us to use and compare two different high-resolution imaging techniques for the analysis of uncoated samples. Helium ion microscopy (HIM) was applied to study the spatial organization of organic and mineral structures, while field emission scanning electron microscopy (FE-SEM) in various modes, including backscattered electron detection, allowed us to discern the gold-labeled proteins. Wild type enamel in late secretory to early maturation stage reveals adjacent to ameloblasts a lengthwise parallel alignment of the enamel matrix proteins, including full-length amelogenin proteins, which then transitions into a more heterogeneous appearance with increasing distance from the mineralization front. The matrix adjacent to crystal bundles forms a smooth and lacey sheath, whereas between enamel prisms it is organized into spherical components that are interspersed with rod-shaped protein. These findings highlight first, that the heterogeneous organization of the enamel matrix can be visualized in mineralized en bloc samples. Second, our results illustrate that the combination of these techniques is a powerful approach to elucidate the 3D structural organization of organic matrix molecules in mineralizing tissue in nanometer resolution.

  3. Helium ion microscopy of enamel crystallites and extracellular tooth enamel matrix

    Directory of Open Access Journals (Sweden)

    Felicitas B Bidlack

    2014-10-01

    Full Text Available An unresolved problem in tooth enamel studies has been to analyze simultaneously and with sufficient spatial resolution both mineral and organic phases in their three dimensional (3D organization in a given specimen. This study aims to address this need using high-resolution imaging to analyze the 3D structural organization of the enamel matrix, especially amelogenin, in relation to forming enamel crystals. Chemically fixed hemi-mandibles from wild type mice were embedded in LR White acrylic resin, polished and briefly etched to expose the organic matrix in developing tooth enamel. Full-length amelogenin was labeled with specific antibodies and 10 nm immuno-gold. This allowed us to use and compare two different high-resolution imaging techniques for the analysis of uncoated samples. Helium ion microscopy (HIM was applied to study the spatial organization of organic and mineral structures, while field emission scanning electron microscopy (FE-SEM in various modes, including backscattered electron detection, allowed us to discern the gold-labeled proteins. Wild type enamel in late secretory to early maturation stage reveals adjacent to ameloblasts a lengthwise parallel alignment of the enamel matrix proteins, including full-length amelogenin proteins, which then transitions into a more heterogeneous appearance with increasing distance from the mineralization front. The matrix adjacent to crystal bundles forms a smooth and lacey sheath, whereas between enamel prisms it is organized into spherical components that are interspersed with rod-shaped protein. These findings highlight first, that the heterogeneous organization of the enamel matrix can be visualized in mineralized en bloc samples. Second, our results illustrate that the combination of these techniques is a powerful approach to elucidate the 3D structural organization of organic matrix molecules in mineralizing tissue in nanometer resolution.

  4. Adhesive interfaces of enamel and dentin prepared by air-abrasion at different distances

    International Nuclear Information System (INIS)

    Chinelatti, Michelle Alexandra; Andreolli do Amaral, Thais Helena; Borsatto, Maria Cristina; Palma-Dibb, Regina Guenka; Corona, Silmara Aparecida Milori

    2007-01-01

    The purpose of this study was to analyse, by scanning electron microscopy (SEM), the morphology of enamel and dentin/adhesive interfaces in cavities prepared by air-abrasion at different working distances. Thirty sound third human molars were selected and, on both their buccal and lingual surfaces, class V cavities were prepared by air-abrasion, at 2-, 4-, 6-, 8- and 10-mm working distances, or high-speed bur (control group). After preparation, all cavities were etched with 35% phosphoric acid gel and restored with Single Bond/Filtek Z-250. Buccal and lingual surfaces were separated and restorations sectioned in a buccolingual direction, providing two sections of each cavity, which were analysed by scanning electron microscopy. It was observed that the distances of 6 and 8 mm promoted more homogeneous dentin/adhesive interfaces, with tags formation, and more uniform for enamel, which were similar to the control group. It may be concluded that the air-abrasion working distance can influence the morphology of enamel and dentin/adhesive interfaces, and the intermediate distances provided better adhesive interfaces

  5. Sound Search Engine Concept

    DEFF Research Database (Denmark)

    2006-01-01

    Sound search is provided by the major search engines, however, indexing is text based, not sound based. We will establish a dedicated sound search services with based on sound feature indexing. The current demo shows the concept of the sound search engine. The first engine will be realased June...

  6. Enamel subsurface damage due to tooth preparation with diamonds.

    Science.gov (United States)

    Xu, H H; Kelly, J R; Jahanmir, S; Thompson, V P; Rekow, E D

    1997-10-01

    In clinical tooth preparation with diamond burs, sharp diamond particles indent and scratch the enamel, causing material removal. Such operations may produce subsurface damage in enamel. However, little information is available on the mechanisms and the extent of subsurface damage in enamel produced during clinical tooth preparation. The aim of this study, therefore, was to investigate the mechanisms of subsurface damage produced in enamel during tooth preparation by means of diamond burs, and to examine the dependence of such damage on enamel rod orientation, diamond particle size, and removal rate. Subsurface damage was evaluated by a bonded-interface technique. Tooth preparation was carried out on two enamel rod orientations, with four clinical diamond burs (coarse, medium, fine, and superfine) used in a dental handpiece. The results of this study showed that subsurface damage in enamel took the form of median-type cracks and distributed microcracks, extending preferentially along the boundaries between the enamel rods. Microcracks within individual enamel rods were also observed. The median-type cracks were significantly longer in the direction parallel to the enamel rods than perpendicular to the rods. Preparation with the coarse diamond bur produced cracks as deep as 84 +/- 30 microns in enamel. Finishing with fine diamond burs was effective in crack removal. The crack lengths in enamel were not significantly different when the removal rate was varied. Based on these results, it is concluded that subsurface damage in enamel induced by tooth preparation takes the form of median-type cracks as well as inter- and intra-rod microcracks, and that the lengths of these cracks are sensitive to diamond particle size and enamel rod orientation, but insensitive to removal rate.

  7. Deformation behavior of human enamel and dentin-enamel junction under compression.

    Science.gov (United States)

    Zaytsev, Dmitry; Panfilov, Peter

    2014-01-01

    Deformation behavior under uniaxial compression of human enamel and dentin-enamel junction (DEJ) is considered in comparison with human dentin. This deformation scheme allows estimating the total response from all levels of the hierarchical composite material in contrast with the indentation, which are limited by the mesoscopic and microscopic scales. It was shown for the first time that dental enamel is the strength (up to 1850MPa) hard tissue, which is able to consider some elastic (up to 8%) and plastic (up to 5%) deformation under compression. In so doing, it is almost undeformable substance under the creep condition. Mechanical properties of human enamel depend on the geometry of sample. Human dentin exhibits the similar deformation behavior under compression, but the values of its elasticity (up to 40%) and plasticity (up to 18%) are much more, while its strength (up to 800MPa) is less in two times. Despite the difference in mechanical properties, human enamel is able to suppress the cracking alike dentin. Deformation behavior under the compression of the samples contained DEJ as the same to dentin. This feature allows a tooth to be elastic-plastic (as dentin) and wear resistible (as enamel), simultaneously. © 2013 Elsevier B.V. All rights reserved.

  8. Nanoindentation creep behavior of human enamel.

    Science.gov (United States)

    He, Li-Hong; Swain, Michael V

    2009-11-01

    In this study, the indentation creep behavior of human enamel was investigated with a nanoindentation system and a Berkovich indenter at a force of 250 mN with one-step loading and unloading method. A constant hold period of 900 s was incorporated into each test at the maximum load as well at 5 mN minimum load during unloading. The indentation creep at the maximum load and creep recovery at the minimum load was described with a double exponential function and compared with other classic viscoelastic models (Debye/Maxwell and Kohlrausch-Williams-Watts). Indentation creep rate sensitivity, m, of human enamel was measured for the first time with a value of approximately 0.012. Enamel displayed both viscoelastic and viscoplastic behavior similar to that of bone. These results indicate that, associated with entrapment of particulates between teeth under functional loading and sliding wear conditions, the enamel may inelastically deform but recover upon its release. This behavior may be important in explaining the excellent wear resistance, antifatigue, and crack resistant abilities of natural tooth structure. (c) 2008 Wiley Periodicals, Inc.

  9. Tooth enamel hypoplasia in PHACE syndrome.

    Science.gov (United States)

    Chiu, Yvonne E; Siegel, Dawn H; Drolet, Beth A; Hodgson, Brian D

    2014-01-01

    Individuals with PHACE syndrome (posterior fossa malformations, hemangiomas, arterial anomalies, cardiac defects, eye abnormalities, sternal cleft, and supraumbilical raphe syndrome) have reported dental abnormalities to their healthcare providers and in online forums, but dental involvement has not been comprehensively studied. A study was conducted at the third PHACE Family Conference, held in Milwaukee, Wisconsin, in July 2012. A pediatric dentist examined subjects at enrollment. Eighteen subjects were enrolled. The median age was 4.2 years (range 9 mos-9 yrs; 14 girls, 4 boys). Eleven of 18 patients had intraoral hemangiomas and five of these (50%) had hypomature enamel hypoplasia. None of the seven patients without intraoral hemangiomas had enamel hypoplasia. No other dental abnormalities were seen. Enamel hypoplasia may be a feature of PHACE syndrome when an intraoral hemangioma is present. Enamel hypoplasia increases the risk of caries, and clinicians should refer children with PHACE syndrome to a pediatric dentist by 1 year of age. © 2014 Wiley Periodicals, Inc.

  10. Microtensile bond strength of enamel after bleaching.

    Science.gov (United States)

    Lago, Andrea Dias Neves; Garone-Netto, Narciso

    2013-01-01

    To evaluate the bond strength of a composite resin to the bovine enamel bleached with 35% hydrogen peroxide. It was used an etching-and-rinse adhesive system employed immediately, 7 and 14 days after the bleaching. Twenty bovine teeth were randomly distributed into 4 groups (n = 5), 3 experimental and 1 control. G1: Unbleached + restoration 14 days after storage in artificial saliva (control); G2: Bleached + restoration immediately after bleaching; G3: Bleached + restoration 7 days after bleaching; G4: Bleached + restoration 14 days after bleaching. Their buccal enamel surfaces were flattened, and a 25 mm² (5 × 5 mm) area from each one of these regions was outlined so as to standardize the experimental region. Universal hybrid composite resin Filtek™Z350 was inserted into four layers of 1 mm each and photo-activated. The bond strength was quantitatively evaluated by a microtensile test (1.0 mm/min) 24 h after the restorative procedures. The failure mode was assessed through scanning electron microscopy (SEM). There was a significant reduction in the bond strength of the restored teeth immediately after the bleaching (G2). There were no significant differences in enamel bond strength between groups G1, G3, and G4. There was a predominance of adhesive and mixed (cohesive + adhesive) failure in all groups. The 7-day-period after the end of the bleaching with 35% hydrogen peroxide was enough to achieve the appropriate values of bond strength to the enamel.

  11. Effect of ozone gas on the shear bond strength to enamel

    Directory of Open Access Journals (Sweden)

    Patrícia Teixeira Pires

    2013-04-01

    Full Text Available Ozone is an important disinfecting agent, however its influence on enamel adhesion has not yet been clarified. Objective: Evaluate the influence of ozone pretreatment on the shear strength of an etch-and-rinse and a self-etch system to enamel and analyze the respective failure modes. Material and Methods: Sixty sound bovine incisors were used. Specimens were randomly assigned to four experimental groups (n=15: Group G1 (Excite® with ozone and group G3 (AdheSE® with ozone were prepared with ozone gas from the HealOzone unit (Kavo® for 20 s prior to adhesion, and groups G2 (Excite® and G4 (AdheSE® were used as control. Teeth were bisected and polished to simulate a smear layer just before the application of the adhesive systems. The adhesives were applied according to the manufacturer's instructions to a standardized 3 mm diameter surface, and a composite (Synergy D6, Coltene Whaledent cylinder with 2 mm increments was build. Specimens were stored in 100% humidity for 24 h at 37°C and then subjected to a thermal cycling regimen of 500 cycles. Shear bond tests were performed with a Watanabe device in a universal testing machine at 5 mm/min. The failure mode was analyzed under scanning electron microscope. Means and standard deviation of shear bond strength (SBS were calculated and difference between the groups was analyzed using ANOVA, Kolmogorov-Smirnov, Levene and Bonferroni. Chi-squared statistical tests were used to evaluate the failure modes. Results: Mean bond strength values and failure modes were as follows: G1- 26.85±6.18 MPa (33.3% of adhesive cohesive failure; G2 - 27.95±5.58 MPa (53.8% of adhesive failures between enamel and adhesive; G3 - 15.0±3.84 MPa (77.8% of adhesive failures between enamel and adhesive and G4 - 13.1±3.68 MPa (36.4% of adhesive failures between enamel and adhesive. Conclusions: Shear bond strength values of both adhesives tested on enamel were not influenced by the previous application of ozone gas.

  12. Effect of ozone gas on the shear bond strength to enamel.

    Science.gov (United States)

    Pires, Patrícia Teixeira; Ferreira, João Cardoso; Oliveira, Sofia Arantes; Silva, Mário Jorge; Melo, Paulo Ribeiro

    2013-01-01

    Ozone is an important disinfecting agent, however its influence on enamel adhesion has not yet been clarified. Evaluate the influence of ozone pretreatment on the shear strength of an etch-and-rinse and a self-etch system to enamel and analyze the respective failure modes. Sixty sound bovine incisors were used. Specimens were randomly assigned to four experimental groups (n=15): Group G1 (Excite® with ozone) and group G3 (AdheSE® with ozone) were prepared with ozone gas from the HealOzone unit (Kavo®) for 20 s prior to adhesion, and groups G2 (Excite®) and G4 (AdheSE®) were used as control. Teeth were bisected and polished to simulate a smear layer just before the application of the adhesive systems. The adhesives were applied according to the manufacturer's instructions to a standardized 3 mm diameter surface, and a composite (Synergy D6, Coltene Whaledent) cylinder with 2 mm increments was build. Specimens were stored in 100% humidity for 24 h at 37°C and then subjected to a thermal cycling regimen of 500 cycles. Shear bond tests were performed with a Watanabe device in a universal testing machine at 5 mm/min. The failure mode was analyzed under scanning electron microscope. Means and standard deviation of shear bond strength (SBS) were calculated and difference between the groups was analyzed using ANOVA, Kolmogorov-Smirnov, Levene and Bonferroni. Chi-squared statistical tests were used to evaluate the failure modes. Mean bond strength values and failure modes were as follows: G1--26.85±6.18 MPa (33.3% of adhesive cohesive failure); G2--27.95±5.58 MPa (53.8% of adhesive failures between enamel and adhesive); G3--15.0±3.84 MPa (77.8% of adhesive failures between enamel and adhesive) and G4--13.1±3.68 MPa (36.4% of adhesive failures between enamel and adhesive). Shear bond strength values of both adhesives tested on enamel were not influenced by the previous application of ozone gas.

  13. Neuropsychological outcomes after Gamma Knife radiosurgery for mesial temporal lobe epilepsy: a prospective multicenter study.

    Science.gov (United States)

    Quigg, Mark; Broshek, Donna K; Barbaro, Nicholas M; Ward, Mariann M; Laxer, Kenneth D; Yan, Guofen; Lamborn, Kathleen

    2011-05-01

    To assess outcomes of language, verbal memory, cognitive efficiency and mental flexibility, mood, and quality of life (QOL) in a prospective, multicenter pilot study of Gamma Knife radiosurgery (RS) for mesial temporal lobe epilepsy (MTLE). RS, randomized to 20 Gy or 24 Gy comprising 5.5-7.5 ml at the 50% isodose volume, was performed on mesial temporal structures of patients with unilateral MTLE. Neuropsychological evaluations were performed at preoperative baseline, and mean change scores were described at 12 and 24 months postoperatively. QOL data were also available at 36 months. Thirty patients were treated and 26 were available for the final 24-month neuropsychological evaluation. Language (Boston Naming Test), verbal memory (California Verbal Learning Test and Logical Memory subtest of the Wechsler Memory Scale-Revised), cognitive efficiency and mental flexibility (Trail Making Test), and mood (Beck Depression Inventory) did not differ from baseline. QOL scores improved at 24 and 36 months, with those patients attaining seizure remission by month 24s accounting for the majority of the improvement. The serial changes in cognitive outcomes, mood, and QOL are unremarkable following RS for MTLE. RS may provide an alternative to open surgery, especially in those patients at risk of cognitive impairment or who desire a noninvasive alternative to open surgery. Wiley Periodicals, Inc. © 2011 International League Against Epilepsy.

  14. Granule cell dispersion is associated with memory impairment in right mesial temporal lobe epilepsy.

    Science.gov (United States)

    Neves, Rafael Scarpa da Costa; de Souza Silva Tudesco, Ivanda; Jardim, Anaclara Prada; Caboclo, Luís Otávio Sales Ferreira; Lancellotti, Carmen; Ferrari-Marinho, Taíssa; Hamad, Ana Paula; Marinho, Murilo; Centeno, Ricardo Silva; Cavalheiro, Esper Abrão; Scorza, Carla Alessandra; Yacubian, Elza Márcia Targas

    2012-11-01

    We analyzed the association of granule cell dispersion (GCD) with memory performance, clinical data and surgical outcome in a series of patients with mesial temporal lobe epilepsy (MTLE) and mesial temporal sclerosis (MTS). Hippocampal specimens from 54 patients with MTLE (27 patients with right MTLE and 27 with left MTLE) and unilateral MTS, who were separated into GCD and no-GCD groups and thirteen controls were studied. Quantitative neuropathological evaluation was performed using hippocampal sections stained with NeuN. Patients' neuropsychological measures, clinical data, type of MTS and surgical outcome were reviewed. GCD occurred in 28 (51.9%) patients. No correlation between GCD and MTS pattern, clinical data or surgical outcome was found. The presence of GCD was correlated with worse visuospatial memory performance in right MTLE, but not with memory performance in left MTLE. GCD may be related to memory impairment in right MTLE-MTS patients. However, the role of GCD in memory function is not precisely defined. Copyright © 2012 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  15. Decision making under ambiguity and under risk in mesial temporal lobe epilepsy.

    Science.gov (United States)

    Delazer, Margarete; Zamarian, Laura; Bonatti, Elisabeth; Kuchukhidze, Giorgi; Koppelstätter, Florian; Bodner, Thomas; Benke, Thomas; Trinka, Eugen

    2010-01-01

    Decision making is essential in everyday life. Though the importance of the mesial temporal lobe in emotional processing and feedback learning is generally recognized, decision making in mesial temporal lobe epilepsy (mTLE) is almost unexplored so far. Twenty-eight consecutive epilepsy patients with drug resistant mTLE and fifty healthy controls performed decision tasks under initial ambiguity (participants have to learn by feedback to make advantageous decisions) and under risk (advantageous choices may be made by estimating risks and by rational strategies). A subgroup analysis compared the performance of patients affected by MRI-verified abnormalities of the hippocampus or amygdala. The effect of lesion side was also assessed. In decision under ambiguity, mTLE patients showed marked deficits and did not improve over the task. Patients with hippocampus abnormality and patients with amygdala abnormality showed comparable deficits. No difference was found between right and left TLE groups. In decision under risk, mTLE patients performed at the same level as controls. Results suggest that mTLE patients have difficulties in learning from feedback and in making decisions in uncertain, ambiguous situations. By contrast, they are able to make advantageous decisions when full information is given and risks, possible gains and losses are exactly defined.

  16. Benign mesial temporal lobe epilepsy: A clinical cohort and literature review.

    Science.gov (United States)

    AlQassmi, Amal; Burneo, Jorge G; McLachlan, Richard S; Mirsattari, Seyed M

    2016-12-01

    We present a single-center retrospective study of benign mesial temporal lobe epilepsy (bMTLE) between 1995 and 2014. Hospital records and clinic charts were reviewed. The clinical, Eelectroencephalographic (EEG), imaging features, and response to treatment with antiepileptic drugs (AEDs) were documented. Patients were included in this study if they were seizure-free for a minimum of 24months with or without an AED. Twenty-seven patients were identified. There were 19 (70%) females, mean age at first seizure was 32.2 (range: 15-80years). In all patients, seizures were mild, and seizure freedom was readily achieved with the initiation of AED therapy. Sixteen patients (59%) had mesial temporal sclerosis (MTS). In three patients, we attempted to discontinue AED therapy after a prolonged period of remission (5-8years), but all had seizure recurrence within 2 to 4weeks. Not all temporal lobe epilepsy is refractory to medication, despite the presence of MTS. Until clinical trials indicate otherwise, surgery is not indicated but life-long medical treatment is advocated. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Right mesial temporal lobe epilepsy impairs empathy-related brain responses to dynamic fearful faces.

    Science.gov (United States)

    Toller, Gianina; Adhimoolam, Babu; Grunwald, Thomas; Huppertz, Hans-Jürgen; Kurthen, Martin; Rankin, Katherine P; Jokeit, Hennric

    2015-03-01

    Unilateral mesial temporal lobe epilepsy (MTLE) has been associated with reduced amygdala responsiveness to fearful faces. However, the effect of unilateral MTLE on empathy-related brain responses in extra-amygdalar regions has not been investigated. Using functional magnetic resonance imaging, we measured empathy-related brain responses to dynamic fearful faces in 34 patients with unilateral MTLE (18 right sided), in an epilepsy (extra-MTLE; n = 16) and in a healthy control group (n = 30). The primary finding was that right MTLE (RMTLE) was associated with decreased activity predominantly in the right amygdala and also in bilateral periaqueductal gray (PAG) but normal activity in the right anterior insula. The results of the extra-MTLE group demonstrate that these reduced amygdala and PAG responses go beyond the attenuation caused by antiepileptic and antidepressant medication. These findings clearly indicate that RMTLE affects the function of mesial temporal and midbrain structures that mediate basic interoceptive input necessary for the emotional awareness of empathic experiences of fear. Together with the decreased empathic concern found in the RMTLE group, this study provides neurobehavioral evidence that patients with RMTLE are at increased risk for reduced empathy towards others' internal states and sheds new light on the nature of social-cognitive impairments frequently accompanying MTLE.

  18. Assessment of natural enamel lesions with optical coherence tomography in comparison with microfocus x-ray computed tomography

    Science.gov (United States)

    Espigares, Jorge; Sadr, Alireza; Hamba, Hidenori; Shimada, Yasushi; Otsuki, Masayuki; Tagami, Junji; Sumi, Yasunori

    2015-01-01

    Abstract. A technology to characterize early enamel lesions is needed in dentistry. Optical coherence tomography (OCT) is a noninvasive method that provides high-resolution cross-sectional images. The aim of this study is to compare OCT with microfocus x-ray computed tomography (μCT) for assessment of natural enamel lesions in vitro. Ten human teeth with visible white spot-like changes on the enamel smooth surface and no cavitation (ICDAS code 2) were subjected to imaging by μCT (SMX-100CT, Shimadzu) and 1300-nm swept-source OCT (Dental SS-OCT, Panasonic Health Care). In μCT, the lesions appeared as radiolucent dark areas, while in SS-OCT, they appeared as areas of increased signal intensity beneath the surface. An SS-OCT attenuation coefficient based on Beer–Lambert law could discriminate lesions from sound enamel. Lesion depth ranged from 175 to 606  μm in SS-OCT. A correlation between μCT and SS-OCT was found regarding lesion depth (R=0.81, p<0.001) and also surface layer thickness (R=0.76, p<0.005). The images obtained clinically in real time using the dental SS-OCT system are suitable for the assessment of natural subsurface lesions and their surface layer, providing comparable images to a laboratory high-resolution μCT without the use of x-ray. PMID:26158079

  19. NASA Space Sounds API

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has released a series of space sounds via sound cloud. We have abstracted away some of the hassle in accessing these sounds, so that developers can play with...

  20. Ectopic expression of dentin sialoprotein during amelogenesis hardens bulk enamel.

    Science.gov (United States)

    White, Shane N; Paine, Michael L; Ngan, Amanda Y W; Miklus, Vetea G; Luo, Wen; Wang, HongJun; Snead, Malcolm L

    2007-02-23

    Dentin sialophosphpoprotein (Dspp) is transiently expressed in the early stage of secretory ameloblasts. The secretion of ameloblast-derived Dspp is short-lived, correlates to the establishment of the dentinoenamel junction (DEJ), and is consistent with Dspp having a role in producing the specialized first-formed harder enamel adjacent to the DEJ. Crack diffusion by branching and dissipation within this specialized first-formed enamel close to the DEJ prevents catastrophic interfacial damage and tooth failure. Once Dspp is secreted, it is subjected to proteolytic cleavage that results in two distinct proteins referred to as dentin sialoprotein (Dsp) and dentin phosphoprotein (Dpp). The purpose of this study was to investigate the biological and mechanical contribution of Dsp and Dpp to enamel formation. Transgenic mice were engineered to overexpress either Dsp or Dpp in their enamel organs. The mechanical properties (hardness and toughness) of the mature enamel of transgenic mice were compared with genetically matched and age-matched nontransgenic animals. Dsp and Dpp contributions to enamel formation greatly differed. The inclusion of Dsp in bulk enamel significantly and uniformly increased enamel hardness (20%), whereas the inclusion of Dpp weakened the bulk enamel. Thus, Dsp appears to make a unique contribution to the physical properties of the DEJ. Dsp transgenic animals have been engineered with superior enamel mechanical properties.

  1. The molecular basis of hereditary enamel defects in humans.

    Science.gov (United States)

    Wright, J T; Carrion, I A; Morris, C

    2015-01-01

    The formation of human enamel is highly regulated at the molecular level and involves thousands of genes. Requisites for development of this highly mineralized tissue include cell differentiation; production of a unique extracellular matrix; processing of the extracellular matrix; altering of cell function during different stages of enamel formation; cell movement and attachment; regulation of ion and protein movement; and regulation of hydration, pH, and other conditions of the microenvironment, to name just a few. Not surprising, there is a plethora of hereditary conditions with an enamel phenotype. The objective of this review was to identify the hereditary conditions listed on Online Mendelian Inheritance in Man (OMIM) that have an associated enamel phenotype and whether a causative gene has been identified. The OMIM database was searched with the terms amelogenesis, enamel, dental, and tooth, and all results were screened by 2 individuals to determine if an enamel phenotype was identified. Gene and gene product function was reviewed on OMIM and from publications identified in PubMed. The search strategy revealed 91 conditions listed in OMIM as having an enamel phenotype, and of those, 71 have a known molecular etiology or linked genetic loci. The purported protein function of those conditions with a known genetic basis included enzymes, regulatory proteins, extracellular matrix proteins, transcription factors, and transmembrane proteins. The most common enamel phenotype was a deficient amount of enamel, or enamel hypoplasia, with hypomineralization defects being reported less frequently. Knowing these molecular defects allows an initial cataloging of molecular pathways that lead to hereditary enamel defects in humans. This knowledge provides insight into the diverse molecular pathways involved in enamel formation and can be useful when searching for the genetic etiology of hereditary conditions that involve enamel. © International & American Associations for

  2. The Molecular Basis of Hereditary Enamel Defects in Humans

    Science.gov (United States)

    Carrion, I.A.; Morris, C.

    2015-01-01

    The formation of human enamel is highly regulated at the molecular level and involves thousands of genes. Requisites for development of this highly mineralized tissue include cell differentiation; production of a unique extracellular matrix; processing of the extracellular matrix; altering of cell function during different stages of enamel formation; cell movement and attachment; regulation of ion and protein movement; and regulation of hydration, pH, and other conditions of the microenvironment, to name just a few. Not surprising, there is a plethora of hereditary conditions with an enamel phenotype. The objective of this review was to identify the hereditary conditions listed on Online Mendelian Inheritance in Man (OMIM) that have an associated enamel phenotype and whether a causative gene has been identified. The OMIM database was searched with the terms amelogenesis, enamel, dental, and tooth, and all results were screened by 2 individuals to determine if an enamel phenotype was identified. Gene and gene product function was reviewed on OMIM and from publications identified in PubMed. The search strategy revealed 91 conditions listed in OMIM as having an enamel phenotype, and of those, 71 have a known molecular etiology or linked genetic loci. The purported protein function of those conditions with a known genetic basis included enzymes, regulatory proteins, extracellular matrix proteins, transcription factors, and transmembrane proteins. The most common enamel phenotype was a deficient amount of enamel, or enamel hypoplasia, with hypomineralization defects being reported less frequently. Knowing these molecular defects allows an initial cataloging of molecular pathways that lead to hereditary enamel defects in humans. This knowledge provides insight into the diverse molecular pathways involved in enamel formation and can be useful when searching for the genetic etiology of hereditary conditions that involve enamel. PMID:25389004

  3. Comparative evaluation of self-etching primers and phosphoric acid effectiveness on composite to enamel bond: an in vitro study.

    Science.gov (United States)

    Patil, Basanagouda S; Rao, Bk Raghavendra; Sharathchandra, Sm; Hegde, Reshma; Kumar, G Vinay

    2013-09-01

    The aim of the present study was to investigate the effectiveness of the one total-etch self-priming adhesive, one two-step self-etching primer adhesive, and one 'all-in-one' self-etching adhesive system on the adhesion of a resin composite to enamel. Thirty-six freshly extracted human mandibular molars were selected for this study. A fat area about 5 mm in diameter was created on the exposed mesial surface of enamel of each tooth by moist grinding with 320, 420 and 600 grit silicon carbide paper. Twelve teeth were randomly assigned into three groups. In group 1, Adper Easy One (3M ESPE), a one step self-etching primer adhesive was applied and light curing unit for 10 seconds. In group 2, Adper SE Plus, a two-step self-etching primer with bottle A containing the aqueous primer and bottle B containing the acidic adhesive was applied and light cured for 10 seconds. Group 3 (control)-etchant 37% phosphoric acid is applied to the surface for 15 seconds and rinsed with water and air dried and adhesive (single bond 2) is applied to the surface and tube is placed and light cured for 20 seconds. Composite material (Z350) was placed in the tube and light cured for 40 seconds in all the groups. Bond strength testing was done using universal testing machine at the enamel-composite interface. The debonded enamel surface was evaluated in stereomicroscope to assess the cohesive, adhesive or mixed fracture. Data was statistically analyzed by one way analysis of variance (ANOVA). Group 1 performed least among all groups with a mean score of 19.46 MPa. Group 2 had a mean score of 25.67 MPa. Group 3 had a mean score of 27.16 MPa. Under the conditions of this in vitro study, the bond strength values of the two-step self-etching primer systems tested were similar to the total-etch. And, one step self-etching primers have lower bond strength compared to the total-etch.

  4. Measuring color change of tooth enamel by in vitro remineralization of white spot lesion.

    Directory of Open Access Journals (Sweden)

    Betina Tolcachir

    2015-12-01

    Full Text Available Objective colour determination is based on calculating the colorimetric distance (ΔE within a colour space. So far, the most used colour space in dentistry is CIE L*a*b (Comission Internationale de l´Éclairage. CIE L*C*h* has been recently developed, showing a better correlation with the perception of the human eye. Objective: To determine the ability of an in vitro remineralisation substance to blend the colour of white spot lesions (WSL with sound enamel, determining ΔE by using the CIE L*C*h* colour space. Methods: In vitro WSL was generated by immersing 10 samples obtained from human third molars in a demineralization solution for 72h. Amorphous calcium phosphate stabilized by casein phosphopeptide (CPP-ACP was then applied for 60 days while maintaining the samples in artificial saliva at 37ºC. To evaluate the colour of enamel, images were taken from the samples placed in specifically designed silicone moulds after generating the WSL (pre-stage and after remineralisation by scanning, applying the colorimetric distance equation (ΔE*CMC according to the Colour Measurement Committee. Results: Treatment with CPP-ACP caused a significant ΔE decrease with respect to the pre-stage (p<0.001, while the analysis of parameters that make up the colour showed a reduction in the difference of hue (∆H (p<0.001 and brightness (∆L (p<0.01 after applying CPP-ACP. Discussion: CPP-ACP penetrated to the depth of the white spot lesion, making its appearance similar to that of the sound enamel, probably because of the formation of different mineral phases than that of the original structure, although pores were not completely filled.

  5. Effects of blue light irradiation on dental enamel remineralization in vitro; Avaliacao dos efeitos promovidos pela radiacao azul na remineralizacao do esmalte dentario in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Ilka Tiemy

    2009-07-01

    This study aimed to investigate the effects of blue radiation on dental enamel remineralization. In addition, a methodology of analysis was developed to evaluate alterations of enamel mineral content by optical coherence tomography. Artificial lesions were formed in bovine dental enamel slabs by immersing the samples in under saturated acetate buffer (2 mL/mm{sup 2} e 6.25 mL/mm{sup 2}). The lesions were irradiated with blue LED (l=455{+-}20nm), with radiant power of 110 mW, irradiance of 1.4 W/cm{sup 2}, radiant exposure of 13.8 J/{sup c}m2 and exposure time of 10 s. Remineralization was induced by pH-cycling model during 8 days. Cross-sectional hardness and optical coherence tomography (OCT) were used to assess mineral changes after remineralization. Hardness data showed that non-irradiated enamel lesions presented higher mineral content than irradiated ones and this difference was more evident in lesions formed in higher solution volume. The analysis of OCT signal also demonstrated that the mineral content of non-irradiated group was higher than in irradiated one; however, no significant difference was observed. Furthermore, significant differences in OCT sign were detected between sound and demineralized enamel. Based on the results obtained in the present study it can be concluded that blue radiation caused an inhibition of enamel remineralization. The methodology adopted for OCT analysis allowed the quantification of enamel mineral loss; however, the remineralization process could not be evaluated by this technique. (author)

  6. Effect of Surface Treatment on Enamel Cracks After Orthodontic Bracket Debonding: Er,Cr:YSGG Laser-Etching Versus Acid-Etching

    Science.gov (United States)

    Ghaffari, Hassanali; Mirhashemi, Amirhossein; Baherimoghadam, Tahereh; Azmi, Amir

    2017-01-01

    Objectives: This study sought to compare enamel cracks after orthodontic bracket debonding in the surfaces prepared with erbium, chromium: yttrium-scandium-galliumgarnet (Er,Cr:YSGG) laser and the conventional acid-etching technique. Materials and Methods: This in-vitro experimental study was conducted on 60 sound human premolars extracted for orthodontic purposes. The teeth were randomly divided into two groups (n=30). The teeth in group A were etched with 37% phosphoric acid gel, while the teeth in group B were subjected to Er,Cr:YSGG laser irradiation (gold handpiece, MZ8 tip, 50Hz, 4.5W, 60μs, 80% water and 60% air). Orthodontic brackets were bonded to the enamel surfaces and were then debonded in both groups. The samples were inspected under a stereomicroscope at ×38 magnification to assess the number and length of enamel cracks before bonding and after debonding. Independent-samples t-test was used to compare the frequency of enamel cracks in the two groups. Levene’s test was applied to assess the equality of variances. Results: No significant difference was noted in the frequency or length of enamel cracks between the two groups after debonding (P>0.05). Conclusions: Despite the same results of the frequency and length of enamel cracks in the two groups and by considering the side effects of acid-etching (demineralization and formation of white spot lesions), Er,Cr:YSGG laser may be used as an alternative to acid-etching for enamel surface preparation prior to bracket bonding. PMID:29296111

  7. Topographical, autobiographical and semantic memory in a patient with bilateral mesial temporal and retrosplenial infarction.

    Science.gov (United States)

    Hepner, Ilana J; Mohamed, Armin; Fulham, Michael J; Miller, Laurie A

    2007-04-01

    According to Consolidation Theory (Squire, 1992, Psychological Review, 99, 195; Squire & Alvarez, 1995, Current Opinion in Neurobiology, 5, 169), the mesial temporal lobes have a time-limited role in the maintenance, storage and retrieval of retrograde declarative memories, such that they are not necessary for recalling remote memories. In contrast, proponents of the Multiple Trace Theory (Fuji, Moscovitch, & Nadel, 2000, Handbook of neuropsychology, 2nd ed., p 223, Amsterdam, New York: Elsevier; Nadel & Moscovitch, 1999, Current Opinion in Neurobiology, 7, 217) posit that the mesial temporal lobe (MTL) is necessary for remembering detailed autobiographical and topographical material from all time periods. A third theory of hippocampal function, the Cognitive Map Theory (O'Keefe & Nadel, 1978, The hippocampus as a cognitive map. Oxford: Clarendon), states that the hippocampus is involved in the processing of allocentric spatial representations. The precise role of the MTL in remote memory has been difficult to elucidate, as the majority of studies present cases with widespread brain damage that often occurred many years prior to testing. We investigated retrograde autobiographical, semantic and topographical memories in a subject (SG) who had recently sustained infarctions confined to the MTL and retrosplenial region bilaterally. Inconsistent with the predictions of Cognitive Map Theory, memory for spatial maps that were learned in the past was preserved. Additional testing indicated that SG suffered from a landmark agnosia, which affected remotely and recently acquired information equally. SG was also poor at imagining which direction he would have to turn his body to move from one landmark to another. In accordance with Consolidation Theory, SG performed similarly to control subjects for remote time periods on various measures of retrograde autobiographical memory and demonstrated intact knowledge regarding famous faces and vocabulary terms that were acquired in

  8. Proteomic Mapping of Dental Enamel Matrix from Inbred Mouse Strains: Unraveling Potential New Players in Enamel.

    Science.gov (United States)

    Lima Leite, Aline; Silva Fernandes, Mileni; Charone, Senda; Whitford, Gary Milton; Everett, Eric T; Buzalaf, Marília Afonso Rabelo

    2018-01-01

    Enamel formation is a complex 2-step process by which proteins are secreted to form an extracellular matrix, followed by massive protein degradation and subsequent mineralization. Excessive systemic exposure to fluoride can disrupt this process and lead to a condition known as dental fluorosis. The genetic background influences the responses of mineralized tissues to fluoride, such as dental fluorosis, observed in A/J and 129P3/J mice. The aim of the present study was to map the protein profile of enamel matrix from A/J and 129P3/J strains. Enamel matrix samples were obtained from A/J and 129P3/J mice and analyzed by 2-dimensional electrophoresis and liquid chromatography coupled with mass spectrometry. A total of 120 proteins were identified, and 7 of them were classified as putative uncharacterized proteins and analyzed in silico for structural and functional characterization. An interesting finding was the possibility of the uncharacterized sequence Q8BIS2 being an enzyme involved in the degradation of matrix proteins. Thus, the results provide a comprehensive view of the structure and function for putative uncharacterized proteins found in the enamel matrix that could help to elucidate the mechanisms involved in enamel biomineralization and genetic susceptibility to dental fluorosis. © 2018 S. Karger AG, Basel.

  9. Correlation between memory, proton magnetic resonance spectroscopy, and interictal epileptiform discharges in temporal lobe epilepsy related to mesial temporal sclerosis.

    Science.gov (United States)

    Mantoan, Marcele Araújo Silva; Caboclo, Luís Otávio Sales Ferreira; de Figueiredo Ferreira Guilhoto, Laura Maria; Lin, Katia; da Silva Noffs, Maria Helena; de Souza Silva Tudesco, Ivanda; Belzunces, Erich; Carrete, Henrique; Bussoletti, Renato Tavares; Centeno, Ricardo Silva; Sakamoto, Américo Ceiki; Yacubian, Elza Márcia Targas

    2009-11-01

    The aim of the study described here was to examine the relationship between memory function, proton magnetic resonance spectroscopy ((1)H-MRS) abnormalities, and interictal epileptiform discharge (IED) lateralization in patients with temporal lobe epilepsy (TLE) related to unilateral mesial temporal sclerosis. We assessed performance on tests of memory function and intelligence quotient (IQ) in 29 right-handed outpatients and 24 controls. IEDs were assessed on 30-minute-awake and 30-minute-sleep EEG samples. Patients had (1)H-MRS at 1.5 T. There was a negative correlation between IQ (P=0.031) and Rey Auditory Verbal Learning Test results (P=0.022) and epilepsy duration; between(1)H-MRS findings and epilepsy duration (P=0.027); and between N-acetylaspartate (NAA) levels and IEDs (P=0.006) in contralateral mesial temporal structures in the left MTS group. (1)H-MRS findings, IEDs, and verbal function were correlated. These findings suggest that IEDs and NAA/(Cho+Cr) ratios reflecting neural metabolism are closely related to verbal memory function in mesial temporal sclerosis. Higher interictal activity on the EEG was associated with a decline in total NAA in contralateral mesial temporal structures.

  10. Neuropsychology Outcomes Following Trephine Epilepsy Surgery: The Inferior Temporal Gyrus Approach for Amygdalohippocampectomy in Medically Refractory Mesial Temporal Lobe Epilepsy.

    Science.gov (United States)

    Schoenberg, Mike R; Clifton, William E; Sever, Ryan W; Vale, Fernando L

    2017-06-08

    Surgery is indicated in cases of mesial temporal lobe epilepsy(MTLE) that are refractory to medical management. The inferior temporal gyrus (ITG) approach provides access to the mesial temporal lobe (MTL) structures with minimal tissue disruption. Reported neuropsychology outcomes following this approach are limited. To report neuropsychological outcomes using an ITG approach to amygdalohippocampectomy (AH) in patients with medically refractory MTLE based on a prospective design. Fifty-four participants had Engel class I/II outcome following resection of MTL using the ITG approach. All participants had localization-related epilepsy confirmed by long-term surface video-electroencephalography and completed pre/postsurgical evaluations that included magnetic resonance imaging (MRI), Wada test or functional MRI, and neuropsychology assessment. Clinical semiology/video-electroencephalography indicated that of the 54 patients, 28 (52%) had left MTLE and 26 (48%) had right MTLE. Dominant hemisphere resections were performed on 23 patients (43%), nondominant on 31(57%). Twenty-nine (29) had pathology-confirmed mesial temporal sclerosis (MTS). Group level analyses found declines in verbal memory for patients with language-dominant resections ( P .05). Neuropsychology outcomes of an ITG approach for selective mesial temporal resection are comparable to other selective AH techniques showing minimal adverse cognitive effects. These data lend support to the ITG approach for selective AH as an option for MTLE. © Congress of Neurological Surgeons 2017.

  11. Theobromine Effects on Enamel Surface Microhardness: In Vitro

    OpenAIRE

    Grace Syafira; Rina Permatasari; Nina Wardani

    2013-01-01

    Dental caries is still a dental health problem in Indonesia. Fluoride, one of the dental caries prevention material, but its safety and the danger of fluorosis is still debated. Theobromine is an alkaloid compound contained in cocoa beans. Theobromine is believed to increase enamel microhardness with mineral changes in the enamel superficial layer. Objectives: To determine the influence of theobromine on the enamel surface microhardness. Methods: This study used 40 premolar tooth crown pieces...

  12. Enamelin is critical for ameloblast integrity and enamel ultrastructure formation.

    Directory of Open Access Journals (Sweden)

    Jan C-C Hu

    Full Text Available Mutations in the human enamelin gene cause autosomal dominant hypoplastic amelogenesis imperfecta in which the affected enamel is thin or absent. Study of enamelin knockout NLS-lacZ knockin mice revealed that mineralization along the distal membrane of ameloblast is deficient, resulting in no true enamel formation. To determine the function of enamelin during enamel formation, we characterized the developing teeth of the Enam-/- mice, generated amelogenin-driven enamelin transgenic mouse models, and then introduced enamelin transgenes into the Enam-/- mice to rescue enamel defects. Mice at specific stages of development were subjected to morphologic and structural analysis using β-galactosidase staining, immunohistochemistry, and transmission and scanning electron microscopy. Enamelin expression was ameloblast-specific. In the absence of enamelin, ameloblasts pathology became evident at the onset of the secretory stage. Although the aggregated ameloblasts generated matrix-containing amelogenin, they were not able to create a well-defined enamel space or produce normal enamel crystals. When enamelin is present at half of the normal quantity, enamel was thinner with enamel rods not as tightly arranged as in wild type suggesting that a specific quantity of enamelin is critical for normal enamel formation. Enamelin dosage effect was further demonstrated in transgenic mouse lines over expressing enamelin. Introducing enamelin transgene at various expression levels into the Enam-/- background did not fully recover enamel formation while a medium expresser in the Enam+/- background did. Too much or too little enamelin abolishes the production of enamel crystals and prism structure. Enamelin is essential for ameloblast integrity and enamel formation.

  13. Enamelin Is Critical for Ameloblast Integrity and Enamel Ultrastructure Formation

    Science.gov (United States)

    Hu, Jan C.-C.; Hu, Yuanyuan; Lu, Yuhe; Smith, Charles E.; Lertlam, Rangsiyakorn; Wright, John Timothy; Suggs, Cynthia; McKee, Marc D.; Beniash, Elia; Kabir, M. Enamul; Simmer, James P.

    2014-01-01

    Mutations in the human enamelin gene cause autosomal dominant hypoplastic amelogenesis imperfecta in which the affected enamel is thin or absent. Study of enamelin knockout NLS-lacZ knockin mice revealed that mineralization along the distal membrane of ameloblast is deficient, resulting in no true enamel formation. To determine the function of enamelin during enamel formation, we characterized the developing teeth of the Enam−/− mice, generated amelogenin-driven enamelin transgenic mouse models, and then introduced enamelin transgenes into the Enam−/− mice to rescue enamel defects. Mice at specific stages of development were subjected to morphologic and structural analysis using β-galactosidase staining, immunohistochemistry, and transmission and scanning electron microscopy. Enamelin expression was ameloblast-specific. In the absence of enamelin, ameloblasts pathology became evident at the onset of the secretory stage. Although the aggregated ameloblasts generated matrix-containing amelogenin, they were not able to create a well-defined enamel space or produce normal enamel crystals. When enamelin is present at half of the normal quantity, enamel was thinner with enamel rods not as tightly arranged as in wild type suggesting that a specific quantity of enamelin is critical for normal enamel formation. Enamelin dosage effect was further demonstrated in transgenic mouse lines over expressing enamelin. Introducing enamelin transgene at various expression levels into the Enam−/− background did not fully recover enamel formation while a medium expresser in the Enam+/− background did. Too much or too little enamelin abolishes the production of enamel crystals and prism structure. Enamelin is essential for ameloblast integrity and enamel formation. PMID:24603688

  14. Indentation Damage and Crack Repair in Human Enamel*

    OpenAIRE

    Rivera, C.; Arola, D.; Ossa, A.

    2013-01-01

    Tooth enamel is the hardest and most highly mineralized tissue in the human body. While there have been a number of studies aimed at understanding the hardness and crack growth resistance behavior of this tissue, no study has evaluated if cracks in this tissue undergo repair. In this investigation the crack repair characteristics of young human enamel were evaluated as a function of patient gender and as a function of the distance from the Dentin Enamel Junction (DEJ). Cracks were introduced ...

  15. Hippocampal Atrophy Is Associated with Altered Hippocampus-Posterior Cingulate Cortex Connectivity in Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis.

    Science.gov (United States)

    Shih, Y C; Tseng, C E; Lin, F-H; Liou, H H; Tseng, W Y I

    2017-03-01

    Unilateral mesial temporal lobe epilepsy and hippocampal sclerosis have structural and functional abnormalities in the mesial temporal regions. To gain insight into the pathophysiology of the epileptic network in mesial temporal lobe epilepsy with hippocampal sclerosis, we aimed to clarify the relationships between hippocampal atrophy and the altered connection between the hippocampus and the posterior cingulate cortex in patients with mesial temporal lobe epilepsy with hippocampal sclerosis. Fifteen patients with left mesial temporal lobe epilepsy with hippocampal sclerosis and 15 healthy controls were included in the study. Multicontrast MR imaging, including high-resolution T1WI, diffusion spectrum imaging, and resting-state fMRI, was performed to measure the hippocampal volume, structural connectivity of the inferior cingulum bundle, and intrinsic functional connectivity between the hippocampus and the posterior cingulate cortex, respectively. Compared with controls, patients had decreased left hippocampal volume (volume ratio of the hippocampus and controls, 0.366% ± 0.029%; patients, 0.277% ± 0.063%, corrected P = .002), structural connectivity of the bilateral inferior cingulum bundle (generalized fractional anisotropy, left: controls, 0.234 ± 0.020; patients, 0.193 ± 0.022, corrected P = .0001, right: controls, 0.226 ± 0.022; patients, 0.208 ± 0.017, corrected P = .047), and intrinsic functional connectivity between the left hippocampus and the left posterior cingulate cortex (averaged z-value: controls, 0.314 ± 0.152; patients, 0.166 ± 0.062). The left hippocampal volume correlated with structural connectivity positively (standardized β = 0.864, P = .001), but it had little correlation with intrinsic functional connectivity (standardized β = -0.329, P = .113). On the contralesional side, the hippocampal volume did not show any significant correlation with structural connectivity or intrinsic functional connectivity ( F 2,12 = 0.284, P = .757, R 2

  16. The Sound of Science

    Science.gov (United States)

    Merwade, Venkatesh; Eichinger, David; Harriger, Bradley; Doherty, Erin; Habben, Ryan

    2014-01-01

    While the science of sound can be taught by explaining the concept of sound waves and vibrations, the authors of this article focused their efforts on creating a more engaging way to teach the science of sound--through engineering design. In this article they share the experience of teaching sound to third graders through an engineering challenge…

  17. Sounds Exaggerate Visual Shape

    Science.gov (United States)

    Sweeny, Timothy D.; Guzman-Martinez, Emmanuel; Ortega, Laura; Grabowecky, Marcia; Suzuki, Satoru

    2012-01-01

    While perceiving speech, people see mouth shapes that are systematically associated with sounds. In particular, a vertically stretched mouth produces a /woo/ sound, whereas a horizontally stretched mouth produces a /wee/ sound. We demonstrate that hearing these speech sounds alters how we see aspect ratio, a basic visual feature that contributes…

  18. Making Sound Connections

    Science.gov (United States)

    Deal, Walter F., III

    2007-01-01

    Sound provides and offers amazing insights into the world. Sound waves may be defined as mechanical energy that moves through air or other medium as a longitudinal wave and consists of pressure fluctuations. Humans and animals alike use sound as a means of communication and a tool for survival. Mammals, such as bats, use ultrasonic sound waves to…

  19. Special Frits for Direct-On Enamelling of Pipelines

    International Nuclear Information System (INIS)

    Berdzenishvili, I.; Siradze, M.; Erokhin, V.; Kldiashvili, R.

    2010-01-01

    The compositions of low-melting zirconium-strontium frits have been developed for direct-on enamelling of pipes. Owing to the given combination of active cations, toxic fluorine and expensive nickel and lithium were eliminated from glass frit compositions. The enamels were subjected to firing by the induction method. In the synthesized enamels, the optimal complex of properties combining high corrosion-resistant and thermo-mechanic indices, adhesive strength and required specifications was realized. These enamels are recommended for testing on pipelines. (author)

  20. Tooth enamel sample preparation using alkaline treatment in ESR dosimetry

    International Nuclear Information System (INIS)

    Yongzeng, Zhou; Jiadong, Wang; Xiaomei, Jia; Ke, Wu; Jianbo, Cong

    2002-01-01

    Tooth enamel sample preparation using alkaline treatment was studied and compared with traditional mechanical method in this paper. 20 adult teeth were used. Samples were placed into NaOH solution. This method requires 4-5 weeks and the enamel was separated from dentin. Experimental results show that 8M NaOH was appropriate for separating enamel from dentin and that there is no difference in background signal relative intensity between samples prepared by mechanical and by chemical methods. There is also no difference in radiosensitivity between samples prepared by two methods mentioned above. Dose response curve for tooth enamel samples isolated by 8M NaOH solution was obtained

  1. Fluoride uptake from restorative dental materials by human enamel

    International Nuclear Information System (INIS)

    Forsten, L.; Rytoemaa, I.; Anttila, A.; Keinonen, J.

    1976-01-01

    The purpose of the study was to determine the uptake in vitro of fluoride from restorative materials by tooth enamel and whether prior etching of the enamel causes a change of uptake. The outermost layer of the labial surface of extracted canines was removed by grinding and the enamel was covered with five different fluoride-containing materials ; a silicate, a composite resin, an amalgam, a silicophosphate, and a polycarboxylate luting cement. The material was either removed immediately or after storing the tooth in distilled water. The fluoride content was determined using a sensitive physical method based on the 19 F (p, αγ) 16 O reaction. In addition, the fluoride content of enamel after etching for different periods of time and of etched enamel which had been in contact with silicate cement was determined. The mean fluoride content of uncovered interior enamel was 226 parts 10 6 . All materials, except the composite, increased clearly the fluoride content of the underlying enamel. Etching of interior enamel also increased the fluoride values. No difference could be shown in fluoride uptake from silicate and composite resin between etched and unetched enamel. (author)

  2. On the R-curve behavior of human tooth enamel.

    Science.gov (United States)

    Bajaj, Devendra; Arola, Dwayne D

    2009-08-01

    In this study the crack growth resistance behavior and fracture toughness of human tooth enamel were quantified using incremental crack growth measures and conventional fracture mechanics. Results showed that enamel undergoes an increase in crack growth resistance (i.e. rising R-curve) with crack extension from the outer to the inner enamel, and that the rise in toughness is a function of distance from the dentin enamel junction (DEJ). The outer enamel exhibited the lowest apparent toughness (0.67+/-0.12 MPam(0.5)), and the inner enamel exhibited a rise in the growth toughness from 1.13 MPam(0.5)/mm to 3.93 MPam(0.5)/mm. The maximum crack growth resistance at fracture (i.e. fracture toughness (K(c))) ranged from 1.79 to 2.37 MPam(0.5). Crack growth in the inner enamel was accompanied by a host of mechanisms operating from the micro- to the nano-scale. Decussation in the inner enamel promoted crack deflection and twist, resulting in a reduction of the local stress intensity at the crack tip. In addition, extrinsic mechanisms such as bridging by unbroken ligaments of the tissue and the organic matrix promoted crack closure. Microcracking due to loosening of prisms was also identified as an active source of energy dissipation. In summary, the unique microstructure of enamel in the decussated region promotes crack growth toughness that is approximately three times that of dentin and over ten times that of bone.

  3. Mineral composition of enamel from two South African population groups

    Energy Technology Data Exchange (ETDEWEB)

    Retief, D H [University of the Witwatersrand, Johannesburg (South Africa). Dental Research Unit; Turkstra, J [University of Fort Hare, Alice (South Africa). Department of Chemistry; Cleaton-Jones, P E; Biddlecombe, F [Atomic Energy Board, Pelindaba, Pretoria (South Africa). Chemistry Div.

    1979-10-01

    The mineral composition of pooled bulk enamel from Black and White South Africans respectively, resident in the Johannesburg area, was determined by neutron activation analysis and high resolution gamma spectromety. The differences between the concentrations of Ca, Cl, Mg, Na, Br and Co in the enamel of the two population groups were apparently not significant. There was a trend for the concentrations of Al, Ag, Au, Fe, Sb, and Zn to be higher in the enamel from the White subjects and for the concentrations of Mn, Se and Sr to be higher in the enamel from the Black subjects.

  4. Enamel alteration following tooth bleaching and remineralization

    OpenAIRE

    Coceska, Emilija; Gjorgievska, Elizabeta; Coleman, Nichola; Gabric, Dragana; Slipper, Ian J.; Stevanovic, Marija; Nicholson, John

    2015-01-01

    The purpose of this study was to compare the effects of professional tooth whitening agents containing highly concentrated hydrogen peroxide (with and without laser activation), on the enamel surface; and the potential of four different toothpastes to remineralize any alterations.\\ud \\ud The study was performed on 50 human molars, divided in two groups: treated with Opalescence® Boost and Mirawhite® Laser Bleaching. Furthermore, each group was divided into five subgroups, a control one and 4 ...

  5. Microtensile bond strength of enamel after bleaching

    Directory of Open Access Journals (Sweden)

    Andréa Dias Neves Lago

    2013-01-01

    Full Text Available Objective: To evaluate the bond strength of a composite resin to the bovine enamel bleached with 35% hydrogen peroxide. It was used an etching-and-rinse adhesive system employed immediately, 7 and 14 days after the bleaching. Materials and Methods: Twenty bovine teeth were randomly distributed into 4 groups (n = 5, 3 experimental and 1 control. G1: Unbleached + restoration 14 days after storage in artificial saliva (control; G2: Bleached + restoration immediately after bleaching; G3: Bleached + restoration 7 days after bleaching; G4: Bleached + restoration 14 days after bleaching. Their buccal enamel surfaces were flattened, and a 25 mm² (5 × 5 mm area from each one of these regions was outlined so as to standardize the experimental region. Universal hybrid composite resin Filtek™Z350 was inserted into four layers of 1 mm each and photo-activated. The bond strength was quantitatively evaluated by a microtensile test (1.0 mm/min 24 h after the restorative procedures. The failure mode was assessed through scanning electron microscopy (SEM. Results: There was a significant reduction in the bond strength of the restored teeth immediately after the bleaching (G2. There were no significant differences in enamel bond strength between groups G1, G3, and G4. There was a predominance of adhesive and mixed (cohesive + adhesive failure in all groups. Conclusion: The 7-day-period after the end of the bleaching with 35% hydrogen peroxide was enough to achieve the appropriate values of bond strength to the enamel.

  6. Temporal lobe epilepsy with mesial temporal sclerosis: hippocampal neuronal loss as a predictor of surgical outcome

    Directory of Open Access Journals (Sweden)

    Anaclara Prada Jardim

    2012-05-01

    Full Text Available OBJECTIVE: To analyze retrospectively a series of patients with temporal lobe epilepsy (TLE and mesial temporal sclerosis (MTS, and the association of patterns of hippocampal sclerosis with clinical data and surgical prognosis. METHOD: Sixty-six patients with medically refractory TLE with unilateral MTS after anterior temporal lobectomy were included. Quantitative neuropathological evaluation was performed on NeuN-stained hippocampal sections. Patient's clinical data and surgical outcome were reviewed. RESULTS: Occurrence of initial precipitating insult (IPI, as well as better postoperative seizure control (i.e. Engel class 1, were associated with classical and severe patterns of hippocampal sclerosis (MTS type 1a and 1b, respectively. CONCLUSION: Quantitative evaluation of hippocampal neuronal loss patterns predicts surgical outcome in patients with TLE-MTS.

  7. Temporal lobe epilepsy with mesial temporal sclerosis: hippocampal neuronal loss as a predictor of surgical outcome.

    Science.gov (United States)

    Jardim, Anaclara Prada; Neves, Rafael Scarpa da Costa; Caboclo, Luís Otávio Sales Ferreira; Lancellotti, Carmen Lucia Penteado; Marinho, Murilo Martinez; Centeno, Ricardo Silva; Cavalheiro, Esper Abrão; Scorza, Carla Alessandra; Yacubian, Elza Márcia Targas

    2012-05-01

    To analyze retrospectively a series of patients with temporal lobe epilepsy (TLE) and mesial temporal sclerosis (MTS), and the association of patterns of hippocampal sclerosis with clinical data and surgical prognosis. Sixty-six patients with medically refractory TLE with unilateral MTS after anterior temporal lobectomy were included. Quantitative neuropathological evaluation was performed on NeuN-stained hippocampal sections. Patient's clinical data and surgical outcome were reviewed. Occurrence of initial precipitating insult (IPI), as well as better postoperative seizure control (i.e. Engel class 1), were associated with classical and severe patterns of hippocampal sclerosis (MTS type 1a and 1b, respectively). Quantitative evaluation of hippocampal neuronal loss patterns predicts surgical outcome in patients with TLE-MTS.

  8. Small calcified lesions suggestive of neurocysticercosis are associated with mesial temporal sclerosis

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    Marcos C. B. Oliveira

    2014-07-01

    Full Text Available Recent studies have suggested a possible relationship between temporal lobe epilepsy with mesial temporal sclerosis (MTS and neurocysticercosis (NC. We performed a case-control study to evaluate the association of NC and MTS. Method: We randomly selected patients with different epilepsy types, including: MTS, primary generalized epilepsy (PGE and focal symptomatic epilepsy (FSE. Patients underwent a structured interview, followed by head computed tomography (CT. A neuroradiologist evaluated the scan for presence of calcified lesions suggestive of NC. CT results were matched with patients’ data. Results: More patients in the MTS group displayed calcified lesions suggestive of NC than patients in the other groups (p=0.002. On multivariate analysis, MTS was found to be an independent predictor of one or more calcified NC lesions (p=0.033. Conclusion: After controlling for confounding factors, we found an independent association between NC calcified lesions and MTS.

  9. Triple pathological findings in a surgically amenable patient with mesial temporal lobe epilepsy

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    Fumin Tong

    2015-01-01

    Full Text Available Mesial temporal sclerosis (MTS is a well-recognized cause of intractable epilepsy; however, coexistence with focal cortical dysplasia (FCD is less common. Middle fossa epidermoid cysts are rare and may involve the temporal lobe. Most epidermoids are clinically silent, slow-growing, and seldom associated with overt symptomatology, including seizures. We describe a patient with multiple comorbidities including left MTS and a large epidermoid cyst involving the left quadrigeminal plate cistern compressing upon the cerebellar vermis and tail of the left hippocampus, resulting in refractory left temporal lobe epilepsy. The patient underwent left anterior temporal lobectomy. The surgical pathology demonstrated a third pathological finding of left temporal FCD type Ia. The patient has been seizure-free since the surgery. This case provides additional information with regard to the understanding of epileptogenicity and surgical planning in patients with MTS and epidermoid cysts.

  10. Little Sounds

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    Baker M. Bani-Khair

    2017-10-01

    Full Text Available The Spider and the Fly   You little spider, To death you aspire... Or seeking a web wider, To death all walking, No escape you all fighters… Weak and fragile in shape and might, Whatever you see in the horizon, That is destiny whatever sight. And tomorrow the spring comes, And the flowers bloom, And the grasshopper leaps high, And the frogs happily cry, And the flies smile nearby, To that end, The spider has a plot, To catch the flies by his net, A mosquito has fallen down in his net, Begging him to set her free, Out of that prison, To her freedom she aspires, Begging...Imploring...crying,  That is all what she requires, But the spider vows never let her free, His power he admires, Turning blind to light, And with his teeth he shall bite, Leaving her in desperate might, Unable to move from site to site, Tied up with strings in white, Wrapped up like a dead man, Waiting for his grave at night,   The mosquito says, Oh little spider, A stronger you are than me in power, But listen to my words before death hour, Today is mine and tomorrow is yours, No escape from death... Whatever the color of your flower…     Little sounds The Ant The ant is a little creature with a ferocious soul, Looking and looking for more and more, You can simply crush it like dead mold, Or you can simply leave it alone, I wonder how strong and strong they are! Working day and night in a small hole, Their motto is work or whatever you call… A big boon they have and joy in fall, Because they found what they store, A lesson to learn and memorize all in all, Work is something that you should not ignore!   The butterfly: I’m the butterfly Beautiful like a blue clear sky, Or sometimes look like snow, Different in colors, shapes and might, But something to know that we always die, So fragile, weak and thin, Lighter than a glimpse and delicate as light, Something to know for sure… Whatever you have in life and all these fields, You are not happier than a butterfly

  11. Topographic assessment of human enamel surface treated with different topical sodium fluoride agents: Scanning electron microscope consideration

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    Gurlal Singh Brar

    2017-01-01

    Full Text Available Introduction: Continuous balanced demineralization and remineralization are natural dynamic processes in enamel. If the balance is interrupted and demineralization process dominates, it may eventually lead to the development of carious lesions in enamel and dentine. Fluoride helps control decay by enhancing remineralization and altering the structure of the tooth, making the surface less soluble. Methodology: One hundred and twenty sound human permanent incisors randomly and equally distributed into six groups as follows: Group I - Control, II - Sodium fluoride solution, III - Sodium fluoride gel, IV - Sodium fluoride varnish, V - Clinpro Tooth Crème (3M ESPE, and VI-GC Tooth Mousse Plus or MI Paste Plus. The samples were kept in artificial saliva for 12 months, and the topical fluoride agents were applied to the respective sample groups as per the manufacturer instructions. Scanning electron microscope (SEM evaluation of all the samples after 6 and 12 months was made. Results: Morphological changes on the enamel surface after application of fluoride in SEM revealed the presence of globular precipitate in all treated samples. Amorphous, globular, and crystalline structures were seen on the enamel surface of the treated samples. Clear differences were observed between the treated and untreated samples. Conclusion: Globular structures consisting of amorphous CaF2precipitates, which acted as a fluoride reservoir, were observed on the enamel surface after action of different sodium fluoride agents. CPP-ACPF (Tooth Mousse and Tricalcium phosphate with fluoride (Clinpro tooth crème are excellent delivery vehicles available in a slow release amorphous form to localize fluoride at the tooth surface.

  12. A randomized CIE L*a*b* evaluation of external bleaching therapy effects on fluorotic enamel stains.

    Science.gov (United States)

    Knösel, Michael; Attin, Rengin; Becker, Klaus; Attin, Thomas

    2008-05-01

    To evaluate the effect of external bleaching on the color and luminosity of fluorotic stains and adjacent, normally mineralized enamel areas by means of CIE L*a*b* colorimetry. Eighteen adolescents with mild to moderate fluorotic stains were randomly assigned to either bleaching group A (n = 9) or control group B. Eligibility criteria were fluorotic stained maxillary incisors or canines and the informed consent of the participants and their guardians. Using a colorimeter, CIE L*a*b* values of maxillary incisors and canines were assessed at baseline (T1) in the center of the fluorotic stained area (F1) and at adjacent, normally mineralized enamel areas (F2). Then, external bleaching with Illumine office (30% hydrogen peroxide, Dentsply DeTrey) was performed for 60 minutes, followed by color reassessment (T2). After 14 days (T3), a 2-week home bleaching period with a daily bleaching time of 1 hour with Illumine home (15% carbamide peroxide, Dentsply DeTrey) was conducted with subsequent color determination (T4). After completion of bleaching therapy, 96.0% of all fluorotic areas (F1) and 100% of normal enamel areas (F2) showed a significant change within group A, compared to 29.4% in control group B. Comparing the collective DeltaE (L*, a*, b*) of F1 and F2, 60.0% of all areas showed significant differences after completion of bleaching therapy, compared to 88.0% initially. Of group B sites, 82.4% showed color differences in the beginning (T1) and 88.2% at the end (T4). Whereas a single 1-hour session of in-office bleaching with 30% hydrogen peroxide does not significantly affect the color and luminosity of fluorotic teeth, a 14-day period of home bleaching leads to an assimilation of the color of the fluorotic stain with the color of surrounding enamel areas due to different responses of sound and fluorotic enamel to the bleaching regime.

  13. Investigation of EPR signals on tooth enamel

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    Pavlenko, A; Mironova-Ulmane, N; Polakov, M; Riekstina, D [Institute of Solid State Physics, University of Latvia, Riga (Latvia)

    2007-12-15

    Calcified tissues are involved in continues metabolic process in human organism exchanging a number of chemical elements with environment. The rate of biochemical reactions is tissue dependent and the slowest one at the tooth enamel, the most mineralized tissue of human organism. The long time stability and unique chemical composition make tooth enamel suitable for number of application. The assessment of individual radiation dose by Electron Paramagnetic Resonance (EPR) and evaluations of elemental composition by Instrumentation Neutron Activation Analysis (INAA) are the well known procedures where properties of tooth enamel intensively used. The current work is focused on investigation of EPR signals and determination of chemical composition on several teeth samples having different origin. The EPR spectra and INAA element content of milk tooth, caries tooth, and paradantose tooth have been compared to each other. The results showed that the intensity of EPR signal is much higher for the caries tooth than the for paradantose tooth that is in agreement with depleted Ca content.

  14. Survival of mossy cells of the hippocampal dentate gyrus in humans with mesial temporal lobe epilepsy.

    Science.gov (United States)

    Seress, László; Abrahám, Hajnalka; Horváth, Zsolt; Dóczi, Tamás; Janszky, József; Klemm, Joyce; Byrne, Richard; Bakay, Roy A E

    2009-12-01

    Hippocampal sclerosis can be identified in most patients with mesial temporal lobe epilepsy (TLE). Surgical removal of the sclerotic hippocampus is widely performed to treat patients with drug-resistant mesial TLE. In general, both epilepsy-prone and epilepsy-resistant neurons are believed to be in the hippocampal formation. The hilar mossy cells of the hippocampal dentate gyrus are usually considered one of the most vulnerable types of neurons. The aim of this study was to clarify the fate of mossy cells in the hippocampus in epileptic humans. Of the 19 patients included in this study, 15 underwent temporal lobe resection because of drug-resistant TLE. Four patients were used as controls because they harbored tumors that had not invaded the hippocampus and they had experienced no seizures. Histological evaluation of resected hippocampal tissues was performed using immunohistochemistry. Mossy cells were identified in the control as well as the epileptic hippocampi by using cocaine- and amphetamine-regulated transcript peptide immunohistochemistry. In most cases the number of mossy cells was reduced and thorny excrescences were smaller in the epileptic hippocampi than in controls; however, there was a significant loss of pyramidal cells and a partial loss of granule cells in the same epileptic hippocampi in which mossy cell loss was apparent. The loss of mossy cells could be correlated with the extent of hippocampal sclerosis, patient age at seizure onset, duration of epilepsy, and frequency of seizures. In many cases large numbers of mossy cells were present in the hilus of the dentate gyrus when most pyramidal neurons of the CA1 and CA3 areas of the Ammon's horn were lost, suggesting that mossy cells may not be more vulnerable to epileptic seizures than the hippocampal pyramidal neurons.

  15. A comparative study on component volumes from outer to inner dental enamel in relation to enamel tufts.

    Science.gov (United States)

    Setally Azevedo Macena, Marcus; de Alencar e Silva Leite, Maria Luísa; de Lima Gouveia, Cíntia; de Lima, Tamires Alcoforado Sena; Athayde, Priscilla Alves Aguiar; de Sousa, Frederico Barbosa

    2014-06-01

    Dental enamel presents marked mechanical properties gradients from outer to inner enamel, a region lacking component volumes profiles. Tufts, structures of inner enamel, have been shown to play a role in enamel resilience. We aimed at comparing component volumes from inner to outer enamel in relation to enamel tufts. Transversal ground sections from the cervical half of unerupted human third molars (n=10) were prepared and histological points were selected along transversal lines (extending from innermost to outer enamel) traced across tufts and adjacent control areas without tufts. Component volumes were measured at each histological point. Component volumes ranges were: 70.6-98.5% (mineral), 0.02-20.78% (organic), 3.8-9.8% (total water), 3-9% (firmly bound water), and 0.02-3.3% (loosely bound water). Inner enamel presented the lowest mineral volumes and the highest non-mineral volumes. Mineral, water and organic contents differed as a function of the distance from innermost enamel but not between the tuft and control lines. Tufts presented opaqueness in polarizing microscopy (feature of fracture lines). Organic volume gradient correlated with a relatively flat profile of loosely bound water. Inner, but not outer enamel, rehydrated after air-dried enamel was heated to 50°C and re-exposed to room conditions, as predicted by the organic/water gradient profiles. Component volumes vary markedly from outer to inner enamel, but not between areas with or without tufts (that behave like fracture lines under polarizing microscopy). Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Hipometabolismo cerebral em pacientes com esclerose mesial temporal demonstrado pelo FDG-PET Brain hypometabolism in patients with mesial-temporal sclerosis demonstrated by FDG-PET

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    PAULO S. DUARTE

    2000-09-01

    Full Text Available O objetivo deste estudo foi avaliar a extensão do hipometabolismo cerebral em pacientes com esclerose mesial temporal (EMT. MÉTODO: Este estudo retrospectivo incluiu 21 pacientes que apresentavam epilepsia parcial complexa refrataria à terapia e que foram selecionados para cirurgia após análise extensa que incluía: EEG de superfície e estudos de neuroimagem (PET, SPECT e ressonância magnética. Todos os pacientes foram submetidos a intervenção cirúrgica e tiveram confirmação histológica de EMT. Uma análise semi-quantitativa foi realizada, utilizando regiões de interesse (ROIs nas seguintes estruturas: lobos frontais, parietais e occipitais, gânglios da base, tálamos, cerebelo e três diferentes regiões nos lobos temporais, que compreendiam o córtex medial, inferior e lateral. Um índice de assimetria (IA foi calculado, comparando as contagens por pixel nas estruturas homólogas em ambos os hemisférios cerebrais. Os IAs das diferentes estruturas foram então correlacionados. RESULTADOS: Uma correlação significativa foi demonstrada entre os IAs do córtex medial dos lobos temporais e aqueles dos lobos frontais, dos lobos parietais, dos gânglios da base e dos tálamos (r = 0,72, 0,62, 0,47 e 0,47 respectivamente com p The purpose of this study was to evaluate the extent of brain hypometabolism in patients with mesial-temporal sclerosis (MTS. METHOD: This retrospective study included 21 patients who had medically refractory complex partial seizures and were selected for surgical therapy after a comprehensive evaluation which included surface EEG recordings and neuroimaging studies (PET, SPECT and MRI. All patients were subjected to surgical intervention and had an histopathological confirmation of MTS. A semi-quantitative analysis of the PET images was performed using regions of interest in the following structures: frontal, parietal and occipital lobes, basal ganglia, thalami, cerebellum and three different regions in the

  17. Targeted p120-catenin ablation disrupts dental enamel development.

    Science.gov (United States)

    Bartlett, John D; Dobeck, Justine M; Tye, Coralee E; Perez-Moreno, Mirna; Stokes, Nicole; Reynolds, Albert B; Fuchs, Elaine; Skobe, Ziedonis

    2010-09-16

    Dental enamel development occurs in stages. The ameloblast cell layer is adjacent to, and is responsible for, enamel formation. When rodent pre-ameloblasts become tall columnar secretory-stage ameloblasts, they secrete enamel matrix proteins, and the ameloblasts start moving in rows that slide by one another. This movement is necessary to form the characteristic decussating enamel prism pattern. Thus, a dynamic system of intercellular interactions is required for proper enamel development. Cadherins are components of the adherens junction (AJ), and they span the cell membrane to mediate attachment to adjacent cells. p120 stabilizes cadherins by preventing their internalization and degradation. So, we asked if p120-mediated cadherin stability is important for dental enamel formation. Targeted p120 ablation in the mouse enamel organ had a striking effect. Secretory stage ameloblasts detached from surrounding tissues, lost polarity, flattened, and ameloblast E- and N-cadherin expression became undetectable by immunostaining. The enamel itself was poorly mineralized and appeared to be composed of a thin layer of merged spheres that abraded from the tooth. Significantly, p120 mosaic mouse teeth were capable of forming normal enamel demonstrating that the enamel defects were not a secondary effect of p120 ablation. Surprisingly, blood-filled sinusoids developed in random locations around the developing teeth. This has not been observed in other p120-ablated tissues and may be due to altered p120-mediated cell signaling. These data reveal a critical role for p120 in tooth and dental enamel development and are consistent with p120 directing the attachment and detachment of the secretory stage ameloblasts as they move in rows.

  18. In-Vitro Comparative Study of In-office and Home Bleaching Agents on Surface Micro-morphology of Enamel

    International Nuclear Information System (INIS)

    Fatima, N.

    2016-01-01

    Objective: To evaluate the effect of home-use bleaching agent containing 16 percent Carbamide Peroxide (CP) and in-office bleaching agent with 38 percentage Hydrogen Peroxide (HP) on surface micro-morphology of enamel. Study Design: An experimental study. Place and Duration of Study: The discs were prepared at Material Engineering Department of NED University of Engineering and Technology, Karachi, and surface morphology was analyzed at Centralized Science Laboratory of Karachi University, Pakistan. Duration of study was one year from January to December 2012. Methodology: Forty five sound human third molar crowns, extracted for periodontal reason, were included in the study. Longitudinal sections were made using diamond disks (0.2 mm) under water lubrication to obtain enamel slabs measuring (3 mm x 3 mm). The slabs were embedded in polystyrene resin by using 2.0 cm diameter PVC molds, leaving the outer enamel surface uncovered by the resin. Ninety dental enamel slabs were prepared. The slabs were then randomly divided into 3 groups. Each group contained thirty specimens (n=30). Group 1 was kept in artificial saliva at 37 degree C in incubator (Memart, Germany) during whole experiment. Group 2 was treated with power whitening gel (White Smile 2011, Germany). Group 3 was treated with tooth whitening pen (White Smile 2011, Germany). The most central region or the region that was most representative of the entire surface area was used. The SEM (Jeol-Japan-JSM6380A, JAPAN) micrographs were examined to determine the type of surface presented. The enamel changes were classified as no or mild alteration, moderate alteration and severe altered surface. Results: Regarding micro-morphology, the enamel surface of control groups showed smooth surface in general with some scattered clear scratches due to the polishing procedure. The specimens bleached in group 2 and group 3, represented areas of mild erosion. Conclusion: Bleaching with 38 percentage Hydrogen Peroxide (HP) and

  19. Optical coherence tomography use in the diagnosis of enamel defects

    Science.gov (United States)

    Al-Azri, Khalifa; Melita, Lucia N.; Strange, Adam P.; Festy, Frederic; Al-Jawad, Maisoon; Cook, Richard; Parekh, Susan; Bozec, Laurent

    2016-03-01

    Molar incisor hypomineralization (MIH) affects the permanent incisors and molars, whose undermineralized matrix is evidenced by lesions ranging from white to yellow/brown opacities to crumbling enamel lesions incapable of withstanding normal occlusal forces and function. Diagnosing the condition involves clinical and radiographic examination of these teeth, with known limitations in determining the depth extent of the enamel defects in particular. Optical coherence tomography (OCT) is an emerging hard and soft tissue imaging technique, which was investigated as a new potential diagnostic method in dentistry. A comparison between the diagnostic potential of the conventional methods and OCT was conducted. Compared to conventional imaging methods, OCT gave more information on the structure of the enamel defects as well as the depth extent of the defects into the enamel structure. Different types of enamel defects were compared, each type presenting a unique identifiable pattern when imaged using OCT. Additionally, advanced methods of OCT image analysis including backscattered light intensity profile analysis and enface reconstruction were performed. Both methods confirmed the potential of OCT in enamel defects diagnosis. In conclusion, OCT imaging enabled the identification of the type of enamel defect and the determination of the extent of the enamel defects in MIH with the advantage of being a radiation free diagnostic technique.

  20. Dental enamel defects in children with coeliac disease

    NARCIS (Netherlands)

    Werink, Claar D.; van Diermen, Denise E.; Aartman, Irene H. A.; Heymans, Hugo S. A.

    2007-01-01

    OBJECTIVE: The aim of this study was to investigate whether Dutch children with proven coeliac disease show specific dental enamel defects, and to asses whether children with the same gastrointestinal complaints, but proved no-coeliac disease, lack these specific dental enamel defects. MATERIALS AND

  1. Brief communication: Enamel thickness and durophagy in mangabeys revisited.

    Science.gov (United States)

    McGraw, W Scott; Pampush, James D; Daegling, David J

    2012-02-01

    The documentation of enamel thickness variation across primates is important because enamel thickness has both taxonomic and functional relevance. The Old World monkeys commonly referred to as mangabeys have figured prominently in investigations of feeding ecology and enamel thickness. In this article, we report enamel thickness values for four mangabey taxa (Cercocebus atys, Cercocebus torquatus, Lophocebus aterrimus, and Lophocebus albigena), offer revised interpretation of the significance of thick enamel in papionin evolution, and place our new data in a broader comparative framework. Our data indicate that all mangabeys have thick enamel and that the values obtained for Cercocebus and Lophocebus equal or exceed those published for most extant non-human primates. In addition, new field data combined with a current reading of the dietary literature indicate that hard foods make up a portion of the diet of every mangabey species sampled to date. Clarification on the relationship between diet and enamel thickness among mangabeys is important not only because of recognition that mangabeys are not a natural group but also because of recent arguments that explain thick enamel as an evolved response to the seasonal consumption of hard foods. Copyright © 2011 Wiley Periodicals, Inc.

  2. Human enamel structure studied by high resolution electron microscopy

    International Nuclear Information System (INIS)

    Wen, S.L.

    1989-01-01

    Human enamel structural features are characterized by high resolution electron microscopy. The human enamel consists of polycrystals with a structure similar to Ca10(PO4)6(OH)2. This article describes the structural features of human enamel crystal at atomic and nanometer level. Besides the structural description, a great number of high resolution images are included. Research into the carious process in human enamel is very important for human beings. This article firstly describes the initiation of caries in enamel crystal at atomic and unit-cell level and secondly describes the further steps of caries with structural and chemical demineralization. The demineralization in fact, is the origin of caries in human enamel. The remineralization of carious areas in human enamel has drawn more and more attention as its potential application is realized. This process has been revealed by high resolution electron microscopy in detail in this article. On the other hand, the radiation effects on the structure of human enamel are also characterized by high resolution electron microscopy. In order to reveal this phenomenon clearly, a great number of electron micrographs have been shown, and a physical mechanism is proposed. 26 references

  3. Targeted overexpression of amelotin disrupts the microstructure of dental enamel.

    Science.gov (United States)

    Lacruz, Rodrigo S; Nakayama, Yohei; Holcroft, James; Nguyen, Van; Somogyi-Ganss, Eszter; Snead, Malcolm L; White, Shane N; Paine, Michael L; Ganss, Bernhard

    2012-01-01

    We have previously identified amelotin (AMTN) as a novel protein expressed predominantly during the late stages of dental enamel formation, but its role during amelogenesis remains to be determined. In this study we generated transgenic mice that produce AMTN under the amelogenin (Amel) gene promoter to study the effect of AMTN overexpression on enamel formation in vivo. The specific overexpression of AMTN in secretory stage ameloblasts was confirmed by Western blot and immunohistochemistry. The gross histological appearance of ameloblasts or supporting cellular structures as well as the expression of the enamel proteins amelogenin (AMEL) and ameloblastin (AMBN) was not altered by AMTN overexpression, suggesting that protein production, processing and secretion occurred normally in transgenic mice. The expression of Odontogenic, Ameloblast-Associated (ODAM) was slightly increased in secretory stage ameloblasts of transgenic animals. The enamel in AMTN-overexpressing mice was much thinner and displayed a highly irregular surface structure compared to wild type littermates. Teeth of transgenic animals underwent rapid attrition due to the brittleness of the enamel layer. The microstructure of enamel, normally a highly ordered arrangement of hydroxyapatite crystals, was completely disorganized. Tomes' process, the hallmark of secretory stage ameloblasts, did not form in transgenic mice. Collectively our data demonstrate that the overexpression of amelotin has a profound effect on enamel structure by disrupting the formation of Tomes' process and the orderly growth of enamel prisms.

  4. Role of crystal arrangement on the mechanical performance of enamel.

    Science.gov (United States)

    An, Bingbing; Wang, Raorao; Zhang, Dongsheng

    2012-10-01

    The superior mechanical properties of enamel, such as excellent penetration and crack resistance, are believed to be related to the unique microscopic structure. In this study, the effects of hydroxyapatite (HAP) crystallite orientation on the mechanical behavior of enamel have been investigated through a series of multiscale numerical simulations. A micromechanical model, which considers the HAP crystal arrangement in enamel prisms, the hierarchical structure of HAP crystals and the inelastic mechanical behavior of protein, has been developed. Numerical simulations revealed that, under compressive loading, plastic deformation progression took place in enamel prisms, which is responsible for the experimentally observed post-yield strain hardening. By comparing the mechanical responses for the uniform and non-uniform arrangement of HAP crystals within enamel prisms, it was found that the stiffness for the two cases was identical, while much greater energy dissipation was observed in the enamel with the non-uniform arrangement. Based on these results, we propose an important mechanism whereby the non-uniform arrangement of crystals in enamel rods enhances energy dissipation while maintaining sufficient stiffness to promote fracture toughness, mitigation of fracture and resistance to penetration deformation. Further simulations indicated that the non-uniform arrangement of the HAP crystals is a key factor responsible for the unique mechanical behavior of enamel, while the change in the nanostructure of nanocomposites could dictate the Young's modulus and yield strength of the biocomposite. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  5. Triad 'Metal – Enamel – Glass'

    International Nuclear Information System (INIS)

    Mukhina, T; Petrova, S; Toporova, V; Fedyaeva, T

    2014-01-01

    This article shows how to change the color of metal and glass. Both these materials are self–sufficient, but sometimes used together. For example, enameling. In this case, the adhesion between metal substrate and stekloobraznae enamel layer, which was conducted on a stretching and a bend, was tested

  6. Targeted overexpression of amelotin disrupts the microstructure of dental enamel.

    Directory of Open Access Journals (Sweden)

    Rodrigo S Lacruz

    Full Text Available We have previously identified amelotin (AMTN as a novel protein expressed predominantly during the late stages of dental enamel formation, but its role during amelogenesis remains to be determined. In this study we generated transgenic mice that produce AMTN under the amelogenin (Amel gene promoter to study the effect of AMTN overexpression on enamel formation in vivo. The specific overexpression of AMTN in secretory stage ameloblasts was confirmed by Western blot and immunohistochemistry. The gross histological appearance of ameloblasts or supporting cellular structures as well as the expression of the enamel proteins amelogenin (AMEL and ameloblastin (AMBN was not altered by AMTN overexpression, suggesting that protein production, processing and secretion occurred normally in transgenic mice. The expression of Odontogenic, Ameloblast-Associated (ODAM was slightly increased in secretory stage ameloblasts of transgenic animals. The enamel in AMTN-overexpressing mice was much thinner and displayed a highly irregular surface structure compared to wild type littermates. Teeth of transgenic animals underwent rapid attrition due to the brittleness of the enamel layer. The microstructure of enamel, normally a highly ordered arrangement of hydroxyapatite crystals, was completely disorganized. Tomes' process, the hallmark of secretory stage ameloblasts, did not form in transgenic mice. Collectively our data demonstrate that the overexpression of amelotin has a profound effect on enamel structure by disrupting the formation of Tomes' process and the orderly growth of enamel prisms.

  7. Chymotrypsin C (Caldecrin) Is Associated with Enamel Development

    Science.gov (United States)

    Lacruz, R.S.; Smith, C.E.; Smith, S.M.; Hu, P.; Bringas, P.; Sahin-Tóth, M.; Moradian-Oldak, J.; Paine, M.L.

    2011-01-01

    Two main proteases cleave enamel extracellular matrix proteins during amelogenesis. Matrix metalloprotease-20 (Mmp20) is the predominant enzyme expressed during the secretory stage, while kallikrein-related peptidase-4 (Klk4) is predominantly expressed during maturation. Mutations to both Mmp20 and Klk4 result in abnormal enamel phenotypes. During a recent whole-genome microarray analysis of rat incisor enamel organ cells derived from the secretory and maturation stages of amelogenesis, the serine protease chymotrypsin C (caldecrin, Ctrc) was identified as significantly up-regulated (> 11-fold) during enamel maturation. Prior reports indicate that Ctrc expression is pancreas-specific, albeit low levels were also noted in brain. We here report on the expression of Ctrc in the enamel organ. Quantitative PCR (qPCR) and Western blot analysis were used to confirm the expression of Ctrc in the developing enamel organ. The expression profile of Ctrc is similar to that of Klk4, increasing markedly during the maturation stage relative to the secretory stage, although levels of Ctrc mRNA are lower than for Klk4. The discovery of a new serine protease possibly involved in enamel development has important implications for our understanding of the factors that regulate enamel biomineralization. PMID:21828354

  8. ONLINE TECHNOLOGICAL MONITORING OF INSULATION DEFECTS IN ENAMELED WIRES

    Directory of Open Access Journals (Sweden)

    V. M. Zolotaryov

    2017-08-01

    Full Text Available In this paper the authors used non-destructive technological monitoring of defects insulation enameled wire with poliimid polymer. The paper is devoted to the statistical method for processing, comparison and analysis of results of measurements of parameters of insulation of enameled wire because of mathematical model of trend for application in active technological monitoring is developed; the recommendations for parameters of such monitoring are used. It is theoretically justified and the possibility of determination of dependence of the error on the velocity of movement of a wire for want of quantifying of defects in enameled insulation by non-destructive tests by high voltage. The dependence of average value of amount of defects for enameled wire with two-sheeted poliimid insulation in a range of nominal diameter 0.56 mm is experimentally determined. The technological monitoring purpose is to reduce the quantifying defects of enameled insulation.

  9. Magnetic resonance in the diagnostic imaging study of mesial temporal sclerosis; Diagnostico por imagen con resonancia magnetica de la esclerosis temporal mesial

    Energy Technology Data Exchange (ETDEWEB)

    Pastor, E; Sanchez, J C; Rodriguez, I; Altuzarra, A; Machado, F [Hospital Universitario Virgen de las Nieves. Granada (Spain); Aguilar, D [Hospital Clinico Universitario San Cecilio. Granada (Spain)

    2001-07-01

    Mesial temporal sclerosis (MTS) consists of hippocampal atrophy and gliosis and is the most common cause of temporal lobe epilepsy. The objective of the authors was to establish a magnetic resonance imaging (MRI) protocol for its diagnosis. A prospective study was carried out in 72 patients with drug resistant complex partial seizures (42 women and 30 men ranging in age from 6 to 66 year: mean: 30 years). Using a 1.5-Tesla magnet, paracoronal sections were made in hippocampi for T1-weighted inversion-recovery images and volume measurements, fluid-attenuated inversion-recovery (FLAIR) and T2 relaxometry. A control group of 30 health volunteers was included in the study. MTS was considered to be indicated by the presence of atrophy and hyperintensity in hippocampi on T2-weighted images. There were no differences among the hippocampi of the healthy individuals. The confidence intervals (mean{+-} 1.96 SD) were 4169 mm''3-5911 mm''3 for volume of right side, 4097 mm''3-5940 mm''3 for volume of left side and 98-113 ms for T2 relaxation time. MTS was detected in 40 patients (55.5%): 23 cases involving the left side, 13 involving the right and 4 cases of bilateral asymmetric involvement. The 95% confidence intervals for the diagnostic validity of the results (sensitivity/specificity) were (88.8%-97.2%)/(87.6%-96.4%) for T1 volumetry, (88.8%-97.2%)(95.7%-100.3%) for FLAIR and (85.4%-96.6%)/(85.4%-96.6%) for T2 relaxometry. In 5 cases of MTS, astrophy of other extra hippocampal structures was also observed, and MTS was associated with an extra hippocampal lesion (dual pathology), especially neurona migration disorders, in 8 patients. Seventeen patients (23.5%) presented lesions without MTS (tumors, cortical dysplasias and heterotopias) and there was no MRI evidence of anomalies in 15 (21%). Twenty-five patients underwent surgical treatment: 20 with MTS (19 diagnosed according to MRI and one in whom there had been no abnormal findings), 4 with tumors and 1 with a ballooned

  10. Magnetic resonance in the diagnostic imaging study of mesial temporal sclerosis; Diagnostico por imagen con resonancia magnetica de la esclerosis temporal mesial

    Energy Technology Data Exchange (ETDEWEB)

    Pastor, E.; Sanchez, J. C.; Rodriguez, I.; Altuzarra, A.; Machado, F. [Hospital Universitario Virgen de las Nieves. Granada (Spain); Aguilar, D. [Hospital Clinico Universitario San Cecilio. Granada (Spain)

    2001-07-01

    Mesial temporal sclerosis (MTS) consists of hippocampal atrophy and gliosis and is the most common cause of temporal lobe epilepsy. The objective of the authors was to establish a magnetic resonance imaging (MRI) protocol for its diagnosis. A prospective study was carried out in 72 patients with drug resistant complex partial seizures (42 women and 30 men ranging in age from 6 to 66 year: mean: 30 years). Using a 1.5-Tesla magnet, paracoronal sections were made in hippocampi for T1-weighted inversion-recovery images and volume measurements, fluid-attenuated inversion-recovery (FLAIR) and T2 relaxometry. A control group of 30 health volunteers was included in the study. MTS was considered to be indicated by the presence of atrophy and hyperintensity in hippocampi on T2-weighted images. There were no differences among the hippocampi of the healthy individuals. The confidence intervals (mean{+-} 1.96 SD) were 4169 mm''3-5911 mm''3 for volume of right side, 4097 mm''3-5940 mm''3 for volume of left side and 98-113 ms for T2 relaxation time. MTS was detected in 40 patients (55.5%): 23 cases involving the left side, 13 involving the right and 4 cases of bilateral asymmetric involvement. The 95% confidence intervals for the diagnostic validity of the results (sensitivity/specificity) were (88.8%-97.2%)/(87.6%-96.4%) for T1 volumetry, (88.8%-97.2%)(95.7%-100.3%) for FLAIR and (85.4%-96.6%)/(85.4%-96.6%) for T2 relaxometry. In 5 cases of MTS, astrophy of other extra hippocampal structures was also observed, and MTS was associated with an extra hippocampal lesion (dual pathology), especially neurona migration disorders, in 8 patients. Seventeen patients (23.5%) presented lesions without MTS (tumors, cortical dysplasias and heterotopias) and there was no MRI evidence of anomalies in 15 (21%). Twenty-five patients underwent surgical treatment: 20 with MTS (19 diagnosed according to MRI and one in whom there had been no abnormal findings

  11. Sound wave transmission (image)

    Science.gov (United States)

    When sounds waves reach the ear, they are translated into nerve impulses. These impulses then travel to the brain where they are interpreted by the brain as sound. The hearing mechanisms within the inner ear, can ...

  12. Making fictions sound real

    DEFF Research Database (Denmark)

    Langkjær, Birger

    2010-01-01

    This article examines the role that sound plays in making fictions perceptually real to film audiences, whether these fictions are realist or non-realist in content and narrative form. I will argue that some aspects of film sound practices and the kind of experiences they trigger are related...... to basic rules of human perception, whereas others are more properly explained in relation to how aesthetic devices, including sound, are used to characterise the fiction and thereby make it perceptually real to its audience. Finally, I will argue that not all genres can be defined by a simple taxonomy...... of sounds. Apart from an account of the kinds of sounds that typically appear in a specific genre, a genre analysis of sound may also benefit from a functionalist approach that focuses on how sounds can make both realist and non-realist aspects of genres sound real to audiences....

  13. Principles of underwater sound

    National Research Council Canada - National Science Library

    Urick, Robert J

    1983-01-01

    ... the immediately useful help they need for sonar problem solving. Its coverage is broad-ranging from the basic concepts of sound in the sea to making performance predictions in such applications as depth sounding, fish finding, and submarine detection...

  14. Effect of various tooth-whitening products on enamel microhardness.

    Science.gov (United States)

    Grobler, S R; Majeed, A; Moola, M H

    2009-11-01

    The purpose of this in vitro study was to evaluate the effect of various tooth-whitening products containing carbamide peroxide (CP) or hydrogen peroxide (HP), on enamel microhardness. Enamel blocks were exposed to: Nite White ACP 10% CP (Group 2, n=10); Yotuel Patient 10% CP (Group 3, n=10); Opalescence PF 10% CP (Group 4, n=10); Opalescence PF 20% CP (Group 5, n=10); Opalescence Treswhite Supreme 10% HP (Group 6, n=10); Yotuel 10 Minutes 30% CP (Group 7, n=10); Opalescence Quick 45% CP (Group 8, n=10), Yotuel Special 35% HP (Group 9, n=10), Opalescence Boost 38% HP (Group 10, n=10) according to the instructions of the manufacturers. The control (Group 1, n=10) was enamel blocks kept in artificial saliva at 37 degrees C without any treatment. The microhardness values were obtained before exposure and after a 14-day treatment period. Specimens were kept in artificial saliva at 37 degrees C between treatments. Data were analysed using Kruskal-Wallis one-way ANOVA and Tukey-Kramer Multiple Comparison Test. Indent marks on the enamel blocks were also examined under the Scanning Electron Microscope. All whitening products decreased enamel microhardness except group 10 but only Groups 2, 3, 4, 5 and 7 showed significant decrease in enamel microhardness as compared to the control group (p enamel. All products tested in this study decreased enamel microhardness except Opalescence Boost 38% HP. The products containing carbamide peroxide were more damaging to enamel because of the longer application times. Nite White ACP 10% CP showed the highest reduction in enamel microhardness as compared to other products tested.

  15. Keratins as components of the enamel organic matrix

    Science.gov (United States)

    Duverger, Olivier; Beniash, Elia; Morasso, Maria I.

    2016-01-01

    Dental enamel is a hardest tissue in the human body, and although it starts as a tissue rich in proteins, by the time of eruption of the tooth in the oral cavity only a small fraction of the protein remains. While this organic matrix of enamel represents less than 1% by weight it plays essential roles in improving both toughness and resilience to chemical attacks. Despite the fact that the first studies of the enamel matrix began in the 19th century its exact composition and mechanisms of its function remain poorly understood. It was proposed that keratin or a keratin-like primitive epithelial component exists in mature enamel, however due to the extreme insolubility of its organic matrix the presence of keratins there was never clearly established. We have recently identified expression of a number of hair keratins in ameloblasts, the enamel secreting cells, and demonstrated their incorporation into mature enamel. Mutation in epithelial hair keratin KRT75 leads to a skin condition called pseudofollicularis barbae. Carriers of this mutation have an altered enamel structure and mechanical properties. Importantly, these individuals have a much higher prevalence of caries. To the best of our knowledge, this is the first study showing a direct link between a mutation in a protein-coding region of a gene and increased caries rates. In this paper we present an overview of the evidence of keratin-like material in enamel that has accumulated over the last 150 years. Furthermore, we propose potential mechanisms of action of KTR75 in enamel and highlight the clinical implications of the link between mutations in KRT75 and caries. Finally, we discuss the potential use of keratins for enamel repair. PMID:26709044

  16. Indentation damage and mechanical properties of human enamel and dentin.

    Science.gov (United States)

    Xu, H H; Smith, D T; Jahanmir, S; Romberg, E; Kelly, J R; Thompson, V P; Rekow, E D

    1998-03-01

    Understanding the mechanical properties of human teeth is important to clinical tooth preparation and to the development of "tooth-like" restorative materials. Previous studies have focused on the macroscopic fracture behavior of enamel and dentin. In the present study, we performed indentation studies to understand the microfracture and deformation and the microcrack-microstructure interactions of teeth. It was hypothesized that crack propagation would be influenced by enamel rods and the dentino-enamel junction (DEJ), and the mechanical properties would be influenced by enamel rod orientation and tooth-to-tooth variation. Twenty-eight human third molars were used for the measurement of hardness, fracture toughness, elastic modulus, and energy absorbed during indentation. We examined the effect of enamel rod orientation by propagating cracks in the occlusal surface, and in the axial section in directions parallel and perpendicular to the occlusal surface. The results showed that the cracks in the enamel axial section were significantly longer in the direction perpendicular to the occlusal surface than parallel. The cracks propagating toward the DEJ were always arrested and unable to penetrate dentin. The fracture toughness of enamel was not single-valued but varied by a factor of three as a function of enamel rod orientation. The elastic modulus of enamel showed a significant difference between the occlusal surface and the axial section. It is concluded that the cracks strongly interact with the DEJ and the enamel rods, and that the mechanical properties of teeth are functions of microstructural orientations; hence, single values of properties (e.g., a single toughness value or a single modulus value) should not be used without information on microstructural orientation.

  17. An Antropologist of Sound

    DEFF Research Database (Denmark)

    Groth, Sanne Krogh

    2015-01-01

    PROFESSOR PORTRAIT: Sanne Krogh Groth met Holger Schulze, newly appointed professor in Musicology at the Department for Arts and Cultural Studies, University of Copenhagen, to a talk about anthropology of sound, sound studies, musical canons and ideology.......PROFESSOR PORTRAIT: Sanne Krogh Groth met Holger Schulze, newly appointed professor in Musicology at the Department for Arts and Cultural Studies, University of Copenhagen, to a talk about anthropology of sound, sound studies, musical canons and ideology....

  18. Broadcast sound technology

    CERN Document Server

    Talbot-Smith, Michael

    1990-01-01

    Broadcast Sound Technology provides an explanation of the underlying principles of modern audio technology. Organized into 21 chapters, the book first describes the basic sound; behavior of sound waves; aspects of hearing, harming, and charming the ear; room acoustics; reverberation; microphones; phantom power; loudspeakers; basic stereo; and monitoring of audio signal. Subsequent chapters explore the processing of audio signal, sockets, sound desks, and digital audio. Analogue and digital tape recording and reproduction, as well as noise reduction, are also explained.

  19. Propagation of sound

    DEFF Research Database (Denmark)

    Wahlberg, Magnus; Larsen, Ole Næsbye

    2017-01-01

    properties can be modified by sound absorption, refraction, and interference from multi paths caused by reflections.The path from the source to the receiver may be bent due to refraction. Besides geometrical attenuation, the ground effect and turbulence are the most important mechanisms to influence...... communication sounds for airborne acoustics and bottom and surface effects for underwater sounds. Refraction becomes very important close to shadow zones. For echolocation signals, geometric attenuation and sound absorption have the largest effects on the signals....

  20. Enamel microstructure and microstrain in the fracture of human and pig molar cusps.

    Science.gov (United States)

    Popowics, T E; Rensberger, J M; Herring, S W

    2004-08-01

    The role of microstructure in enamel strain and breakage was investigated in human molar cusps and those of the pig, Sus scrofa. Rosette strain gauges were affixed to cusp surfaces (buccal human M3, n=15, and lingual pig M1, n=13), and a compressive load was applied to individual cusps using an MTS materials testing machine. Load and strain data were recorded simultaneously until cusp fracture, and these data were used to estimate enamel stresses, principal strains, and stiffness. Fractured and polished enamel fragments were examined in multiple planes using scanning electron microscopy (SEM). Human cusp enamel showed greater stiffness than pig enamel (P=0.02), and tensile stress at yield was higher (17.9 N/mm2 in humans versus 8.9 N/mm2 in pigs, P=0.06). SEM revealed enamel rod decussation in both human and pig enamel; however, only pig enamel showed a decussation plane between rod and inter-rod crystallites. Human inter-rod enamel was densely packed between rods, whereas in pig enamel, inter-rod enamel formed partitions between rows of enamel rods. Overall, human enamel structure enabled molar cusps to withstand horizontal tensile stress during both elastic and plastic phases of compressive loading. In contrast, pig cusp enamel was less resistant to horizontal tensile stresses, but appeared to fortify the enamel against crack propagation in multiple directions. These structural and biomechanical differences in cusp enamel are likely to reflect species-level differences in occlusal function.

  1. Gold Enamel Choumps – A Case report

    Directory of Open Access Journals (Sweden)

    Sargam D. Kotecha

    2016-09-01

    Full Text Available Tooth jewellery has been practiced since time immemorial and has become an increasingly popular trend. This case report provides a brief insight into a kind of tooth adornment/a tooth tattoo on the enamel prevalent in parts of western Uttar Pradesh, India locally known as a ‘Choump’. A tooth tattooed with ‘Choumps’ has extremely low incidence and could be used as an identification trait. Tooth adornment with ‘Choumps’ has been reported in adults however, this is the first reported case of ‘Choumps’ in children.

  2. Comparison of shear bond strength between unfilled resin to dry enamel and dentin bonding to moist and dry enamel

    Directory of Open Access Journals (Sweden)

    Yasini E.

    2005-05-01

    Full Text Available Statement of Problem: The use of dentine bondings on enamel and dentin in total etch protocols has recently become popular. Unfilled resin is hydrophobic and dentin bonding is hydrophilic in nature. This chemical difference could be effective in enamel bonding process. Purpose: The aim of this study was to compare the shear bond strength of unfilled resin to dry enamel and dentin bonding to dry and moist enamel. Materials and Methods: In this experimental study, a total of 30 incisor teeth were used. The specimens were randomly assigned to three groups of 10. 37% phosphoric acid etchant was applied to the enamel surfaces in each group for 15 seconds, rinsed with water for 20 seconds and dried for 20 seconds with compressed air in groups one and two. After conditioning, group 1 received unfilled resin (Margin Bond, Colten and group 2 received dentin bonding (Single Bond, 3M and in group 3 after conditioning and rinsing with water, a layer of dentin bonding (Single Bond was applied on wet enamel. The enamel and dentin bonding were light cured for 20 seconds. A ring mold 3.5 mm in diameter and 2 mm height was placed over the specimens to receive the composite filling material (Z100, 3M. The composite was cured for 40 seconds. The specimens were thermocycled and shear bond strengths were determined using an Instron Universal Testing Machine. The findings were analyzed by ANOVA One-Way and Tukey HSD tests. Results: Shear bond strength of dentin bonding to dry enamel was significantly less than unfilled resin to dry enamel (P<0.05. There was no significant difference between the bond strength of dentin bonding to moist and dry enamel. In addition bond strength of dentin bonding to wet enamel was not significantly different from unfilled resin to dry enamel. Conclusion: Based on the findings of this study, it is suggested that enamel surface should remain slightly moist after etching before bonding with single bond but when using unfilled resin, the

  3. Temporal lobe volume predicts Wada memory test performance in patients with mesial temporal sclerosis.

    Science.gov (United States)

    Ding, Kan; Gong, Yunhua; Modur, Pradeep N; Diaz-Arrastia, Ramon; Agostini, Mark; Gupta, Puneet; McColl, Roderick; Hays, Ryan; Van Ness, Paul

    2016-02-01

    The Wada test is widely used in the presurgical evaluation of potential temporal lobectomy patients to predict postoperative memory function. Expected asymmetry (EA), defined as Wada memory lateralized to the nonsurgical hemisphere, or a higher score after injection of the surgical hemisphere would be considered favorable in terms of postoperative memory outcome. However, in some cases, nonlateralized memory (NM) results, with no appreciable asymmetry, may occur because of impaired scores after both injections, often leading to denial of surgery. The reason for such nonlateralized Wada memory in patients with intractable temporal lobe epilepsy (TLE) remains unclear. Given that quantitative morphometric magnetic resonance imaging studies in TLE patients have shown bilateral regional atrophy in temporal and extratemporal structures, we hypothesized that the volume loss in contralateral temporal structures could contribute to nonlateralized Wada memory performance. To investigate this, we examined the relationship between the volume changes of temporal structures and Wada memory scores in patients with intractable TLE with mesial temporal sclerosis (MTS) using an age- and gender-matched control group. Memory was considered nonlateralized if the absolute difference in the total correct recall scores between ipsilateral and contralateral injections was memory was lateralized in 15 and nonlateralized in 6 patients, with all the nonlateralized scores being observed in left TLE. The recall scores after ipsilateral injection were significantly lower in patients with an NM profile than an EA profile (23 ± 14% vs. 59 ± 18% correct recall, p ≤ 0.001). However, the recall scores after contralateral injection were low but similar between the two groups (25 ± 17% vs. 25 ± 15% correct recall, p=0.97). Compared to controls, all the patients showed greater volume loss in the temporal regions. However, patients with a NM profile showed significantly more volume loss than those

  4. Micro-computed tomography study of the internal anatomy of mesial root canals of mandibular molars.

    Science.gov (United States)

    Villas-Bôas, Marcelo Haas; Bernardineli, Norberti; Cavenago, Bruno Cavalini; Marciano, Marina; Del Carpio-Perochena, Aldo; de Moraes, Ivaldo Gomes; Duarte, Marco H; Bramante, Clovis M; Ordinola-Zapata, Ronald

    2011-12-01

    The aim of this study was to determine the mesiodistal and buccolingual diameter, apical volume, and the presence of isthmuses at the apical level of mesial root canals of mandibular molars. Sixty extracted first and second mandibular molars were scanned by using a SkyScan 1076 micro-computed tomography system with a voxel size of 18 μm. The apical thirds of the samples were reconstructed to allow a perpendicular section of the apical third by using the multiplanar reconstruction tool of the OsiriX software. The mesiodistal and the buccolingual distances of root canals were measured between the 1- to 4-mm levels. The type of root canal isthmuses present at these levels was classified by using modified criteria of Hsu and Kim. The volume of the root canal anatomy between the 1- to 3-mm apical levels was obtained by using the CTAN-CTVOL software. The medians of the mesiodistal diameter at the 1-, 2-, 3-, and 4-mm levels in the mesiobuccal and mesiolingual canals were 0.22 and 0.23 mm, 0.27 and 0.27 mm, 0.30 and 0.30 mm, and 0.36 and 0.35 mm, respectively. The buccolingual lengths at the 1-, 2-, 3-, and 4-mm levels were 0.37-0.35 mm, 0.55-0.41 mm, 0.54-0.49 mm, and 0.54 and 0.60 mm, respectively. The presence of isthmuses was more prevalent at the 3- to 4-mm level. However, 27 cases presented complete or incomplete isthmuses at the 1-mm apical level. The mean of the volume of the apical third was 0.83 mm(3), with a minimum value of 0.02 and a maximum value of 2.4 mm(3). Mesial root canals of mandibular molars do not present a consistent pattern. A high variability of apical diameters exists. The presence of isthmuses at the apical third was not uncommon even at the 1-mm apical level. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  5. Granule cell dispersion is not a predictor of surgical outcome in temporal lobe epilepsy with mesial temporal sclerosis.

    Science.gov (United States)

    da Costa Neves, Rafael Scarpa; Jardim, Anaclara Prada; Caboclo, Luís Otávio; Lancellotti, Carmen; Marinho, Taissa Ferrari; Hamad, Ana Paula; Marinho, Murilo; Centeno, Ricardo; Cavalheiro, Esper Abrão; Scorza, Carla Alessandra; Targas Yacubian, Elza Márcia

    2013-01-01

    The aim of this retrospective study of a series of patients with mesial temporal lobe epilepsy (MTLE) and mesial temporal sclerosis (MTS) was to analyze the association of granule cell dispersion (GCD) with surgical prognosis, patterns of MTS and clinical data. Hippocampal specimens from 66 patients with MTLE and unilateral MTS and from 13 controls were studied. Quantitative neuropathological evaluation was performed on NeuN-stained hippocampal sections. Patients' clinical data, types of MTS and surgical outcome were reviewed. GCD occurred in 45.5% of cases and was not correlated with clinical variable. More severe neuronal loss was observed in patients with GCD. Except for MTS Type 2 - observed only in four no- GCD patients - groups did not differ with respect to the types of MTS. Surgical outcome was similar in both groups. In conclusion, GCD was associated with the degree of hippocampal cell loss, but was not a predictor of surgical outcome.

  6. Nonvisual spatial navigation fMRI lateralizes mesial temporal lobe epilepsy in a patient with congenital blindness.

    Science.gov (United States)

    Toller, Gianina; Adhimoolam, Babu; Grunwald, Thomas; Huppertz, Hans-Jürgen; König, Kristina; Jokeit, Hennric

    2015-01-01

    Nonvisual spatial navigation functional magnetic resonance imaging (fMRI) may help clinicians determine memory lateralization in blind individuals with refractory mesial temporal lobe epilepsy (MTLE). We report on an exceptional case of a congenitally blind woman with late-onset left MTLE undergoing presurgical memory fMRI. To activate mesial temporal structures despite the lack of visual memory, the patient was requested to recall familiar routes using nonvisual multisensory and verbal cues. Our findings demonstrate the diagnostic value of a nonvisual fMRI task to lateralize MTLE despite congenital blindness and may therefore contribute to the risk assessment for postsurgical amnesia in rare cases with refractory MTLE and accompanying congenital blindness.

  7. Abnormal sound detection device

    International Nuclear Information System (INIS)

    Yamada, Izumi; Matsui, Yuji.

    1995-01-01

    Only components synchronized with rotation of pumps are sampled from detected acoustic sounds, to judge the presence or absence of abnormality based on the magnitude of the synchronized components. A synchronized component sampling means can remove resonance sounds and other acoustic sounds generated at a synchronously with the rotation based on the knowledge that generated acoustic components in a normal state are a sort of resonance sounds and are not precisely synchronized with the number of rotation. On the other hand, abnormal sounds of a rotating body are often caused by compulsory force accompanying the rotation as a generation source, and the abnormal sounds can be detected by extracting only the rotation-synchronized components. Since components of normal acoustic sounds generated at present are discriminated from the detected sounds, reduction of the abnormal sounds due to a signal processing can be avoided and, as a result, abnormal sound detection sensitivity can be improved. Further, since it is adapted to discriminate the occurrence of the abnormal sound from the actually detected sounds, the other frequency components which are forecast but not generated actually are not removed, so that it is further effective for the improvement of detection sensitivity. (N.H.)

  8. Modelling Hyperboloid Sound Scattering

    DEFF Research Database (Denmark)

    Burry, Jane; Davis, Daniel; Peters, Brady

    2011-01-01

    The Responsive Acoustic Surfaces workshop project described here sought new understandings about the interaction between geometry and sound in the arena of sound scattering. This paper reports on the challenges associated with modelling, simulating, fabricating and measuring this phenomenon using...... both physical and digital models at three distinct scales. The results suggest hyperboloid geometry, while difficult to fabricate, facilitates sound scattering....

  9. Comparison of the shear bond strength of self-adhesive resin cements to enamel and dentin with different protocol of application.

    Science.gov (United States)

    Moghaddas, Mohammad Javad; Hossainipour, Zahra; Majidinia, Sara; Ojrati, Najmeh

    2017-08-01

    The aim of the present study was to determine the shear bond strength of self-adhesive resin cements to enamel and dentin with and without surface treatments, and compare them with conventional resin cement as the control group. In this experimental study, buccal and lingual surface of the thirty sound human premolars were polished in order to obtain a flat surface of enamel (E) in buccal, and dentin (D) in lingual. Sixty feldspathic ceramic blocks (2×3×3 mm) were prepared and randomly divided into six groups (n=10). Each block was cemented to the prepared surface (30 enamel and 30 dentin surface) according to different protocol: E1 and D1; RelyX ARC as control group, E2, D2; RelyX Unicem, E3, D3; acid etching +RelyX Unicem. The specimens were termocycled and subjected to shear forces by a universal testing machine at a cross head speed of 0.5 mm/min. The mode of fracture were evaluated by stereomicroscope. Data were analyzed with descriptive statistical methods using SPSS version 15. One-way ANOVA, and post hoc Tukey tests were used to compare bond strengths between the groups with different adhesives at α=0.05. Statistical analysis showed no significant differences within the enamel subgroups, but there were significant differences within the dentinal subgroups, and statistically significant differences were found between the groups D1and D3 (p=0.02). Comparison between similar enamel and dentinal subgroups showed that there was a significant difference just between the subgroups E3 and D3 (p=0.01). Elective etching of enamel did not lead to significant increase in the shear bond strength of RelyX Unicem in comparison to RelyX ARC. On the other hand, elective etching of dentin reduces the bond strength of RelyX Unicem with the dentin.

  10. Microshear Bond Strength of OptiBond All-in-One Self-adhesive Agent to Er:YAG Laser Treated Enamel After Thermocycling and Water Storage.

    Science.gov (United States)

    Kasraei, Shahin; Yarmohammadi, Ebrahim; Ghazizadeh, Mohammad Vahid

    2016-01-01

    Introduction: This study aimed to compare the microshear bond strength of composite to enamel treated with Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) laser using a self-etch one step bonding agent. Methods: Seventy-six enamel surfaces were prepared from 38 sound human third molar teeth. Specimens were randomly divided into four groups of 18. The enamel surface in half the specimens was irradiated with Er:YAG laser. One extra specimen from each group was evaluated under a scanning electron microscope (SEM). Composite micro-cylinders were bonded to the specimen surfaces using OptiBond All-In-One (OB) adhesive agent and stored in distilled water for 24 hours. Half the specimens were thermocycled (2000 cycles) and stored in distilled water at 37°C for three months (TW). The microshear bond strength of composite to enamel was measured using a universal testing machine at a crosshead speed of 1 mm/min. The fractured surfaces were evaluated under a stereomicroscope at ×40 magnification to determine the mode of failure. Data were analyzed using repeated measures analysis of variance (ANOVA) and t test. Results: The mean values (±standard deviation) were 17.96 ± 2.92 MPa in OB group, 22.29 ± 4.25 MPa in laser + OB group, 18.11 ± 3.52 MPa in laser + OB + TW group and 9.42 ± 2.47 MPa in OB + TW group. Repeated measures ANOVA showed that laser irradiation increased the microshear bond strength ( P Enamel surface preparation with Er:YAG laser is recommended to enhance the durability of the bond of self-etch bonding systems to enamel.

  11. Combination effect of fluoride dentifrices and varnish on deciduous enamel demineralization

    Directory of Open Access Journals (Sweden)

    Alessandra Gatti

    2011-10-01

    Full Text Available The aim of this study was to evaluate the anticaries potential of 500 or 1100 ppm F dentifrices combined with fluoride varnish using a pH-cycling regimen. Seventy primary canines were covered with nail polish, leaving a 4×4 mm window on their buccal surface, and randomly assigned into 7 groups (n = 10: S: sound enamel not submitted to the pH-cycling regimen or treatment; N: negative control, submitted to the pH-cycling regimen without any treatment; D1 and D2: subjected to the pH-cycling regimen and treated twice daily with 1100 or 500 ppm F dentifrice, respectively; VF: fluoride varnish (subjected to F-varnish before and in the middle of the pH-cycling regimen; and VF+D1 and VF+D2. After 10 days, the teeth were sectioned, and enamel demineralization was assessed by cross-sectional hardness at different distances from the dental surface. Data were analyzed using a two-way ANOVA followed by Tukey's test. Dentifrice with 1100 ppm F and the combination of F-varnish with the dentifrices significantly reduced enamel demineralization compared with the negative control (p 0.05. The effect of combining F-varnish with the dentifrices was not greater than the effect of the dentifrices alone (p < 0.05. The data suggest that the combination of F-varnish with dentifrices containing 500 and 1100 ppm F is not more effective in reducing demineralization in primary teeth than the isolated effect of dentifrice containing 1100 ppm F.

  12. Identification and Endodontic Management of Middle Mesial Canal in Mandibular Second Molar Using Cone Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Bonny Paul

    2015-01-01

    Full Text Available Endodontic treatments are routinely done with the help of radiographs. However, radiographs represent only a two-dimensional image of an object. Failure to identify aberrant anatomy can lead to endodontic failure. This case report presents the use of three-dimensional imaging with cone beam computed tomography (CBCT as an adjunct to digital radiography in identification and management of mandibular second molar with three mesial canals.

  13. Differential gene expression in dentate granule cells in mesial temporal lobe epilepsy with and without hippocampal sclerosis.

    Science.gov (United States)

    Griffin, Nicole G; Wang, Yu; Hulette, Christine M; Halvorsen, Matt; Cronin, Kenneth D; Walley, Nicole M; Haglund, Michael M; Radtke, Rodney A; Skene, J H Pate; Sinha, Saurabh R; Heinzen, Erin L

    2016-03-01

    Hippocampal sclerosis is the most common neuropathologic finding in cases of medically intractable mesial temporal lobe epilepsy. In this study, we analyzed the gene expression profiles of dentate granule cells of patients with mesial temporal lobe epilepsy with and without hippocampal sclerosis to show that next-generation sequencing methods can produce interpretable genomic data from RNA collected from small homogenous cell populations, and to shed light on the transcriptional changes associated with hippocampal sclerosis. RNA was extracted, and complementary DNA (cDNA) was prepared and amplified from dentate granule cells that had been harvested by laser capture microdissection from surgically resected hippocampi from patients with mesial temporal lobe epilepsy with and without hippocampal sclerosis. Sequencing libraries were sequenced, and the resulting sequencing reads were aligned to the reference genome. Differential expression analysis was used to ascertain expression differences between patients with and without hippocampal sclerosis. Greater than 90% of the RNA-Seq reads aligned to the reference. There was high concordance between transcriptional profiles obtained for duplicate samples. Principal component analysis revealed that the presence or absence of hippocampal sclerosis was the main determinant of the variance within the data. Among the genes up-regulated in the hippocampal sclerosis samples, there was significant enrichment for genes involved in oxidative phosphorylation. By analyzing the gene expression profiles of dentate granule cells from surgically resected hippocampal specimens from patients with mesial temporal lobe epilepsy with and without hippocampal sclerosis, we have demonstrated the utility of next-generation sequencing methods for producing biologically relevant results from small populations of homogeneous cells, and have provided insight on the transcriptional changes associated with this pathology. Wiley Periodicals, Inc. © 2016

  14. Enamel formation in vitro in mouse molar explants exposed to amelogenin polypeptides ATMP and LRAP on enamel development.

    Science.gov (United States)

    Ravindranath, Rajeswari M H; Devarajan, Asokan; Bringas, Pablo

    2007-12-01

    The enamel matrix contains amelogenin, leucine-rich amelogenin-polypeptide (LRAP), resulting from alternative splicing of the primary amelogenin-RNA transcript and tyrosine-rich amelogenin-polypeptide (TRAP), a proteolytic product of amelogenin. Presence of amelogenin-trityrosyl-motif peptide (ATMP) distinguishes TRAP from LRAP. The roles of these polypeptides in the formation of enamel remain to be elucidated. The mouse in vitro molar tooth-organ developed from bud stage (E16) was exposed to LRAP, ATMP, and mutated ATMP (T-ATMP, third proline replaced by threonine). The histology and morphometry of the explants on day-12 in culture was examined using Mallory's stain. Guanidine-HCl soluble protein concentrations of explants were compared. The enamel width and protein solubility indicate that the explant on day-12 is comparable to postnatal molar on day-3 in vivo. The enamel of both untreated explants as well as that in vivo is fuchinophilic (acid fuchsin, AF+). ATMP reduced the ameloblast-height, accumulated AF+ spherules at the apical end of ameloblasts, and disrupted enamel-dentin bonding. T-ATMP abrogated deposition of AF+ material on the aniline blue positive (AB+) enamel matrix. LRAP reduced ameloblast-height, increased the enamel-width without disruption (at 17.25 nmol) and increased the density of AF+ dentinal tubules. AF+ substance from the tubules is released onto the surface of the dentin. The Guanidine-HCl-soluble protein is elevated in ATMP-treated explants but decreased in LRAP-treated explants. Exogenous ATMP, T-ATMP and LRAP have divergent effects on developing enamel. Exogenous ATMP, but not LRAP, abrogates enamel-dentin bonding at 17.25 nmol. LRAP may play a role in the differentiation of ameloblasts, growth of enamel and formation of dentinal tubules.

  15. Testing functional and morphological interpretations of enamel thickness along the deciduous tooth row in human children.

    OpenAIRE

    Mahoney, Patrick

    2013-01-01

    The significance of a gradient in enamel thickness along the human permanent molar row has been debated in the literature. Some attribute increased enamel thickness from first to third molars to greater bite force during chewing. Others argue that thicker third molar enamel relates to a smaller crown size facilitated by a reduced dentin component. Thus, differences in morphology, not function, explains enamel thickness. This study draws on these different interpretive models to assess enamel ...

  16. Role of Prism Decussation on Fatigue Crack Growth and Fracture of Human Enamel

    OpenAIRE

    Bajaj, Devendra; Arola, Dwayne

    2009-01-01

    The role of prism decussation on the crack growth resistance of human enamel is evaluated. Miniature inset Compact Tension (CT) specimens embodying a section of cuspal enamel were subjected to Mode I cyclic or monotonic loads. Cracks were grown in either the forward (from outer enamel inwards) or reverse (from inner enamel outwards) direction and the responses were compared quantitatively. Results showed that the outer enamel exhibits lower resistance to the inception and growth of cracks. Re...

  17. Molecular Basis of Human Enamel Defects

    Directory of Open Access Journals (Sweden)

    Chatzopoulos Georgios

    2014-03-01

    Full Text Available During eruption of teeth in the oral cavity, the effect of gene variations and environmental factors can result in morphological and structural changes in teeth. Amelogenesis imperfecta is a failure which is detected on the enamel of the teeth and clinical picture varies by the severity and type of the disease. Classification of the types of amelogenesis imperfecta is determined by histological, genetic, clinical and radiographic criteria. Specifically, there are 4 types of amelogenesis imperfecta (according to Witkop: hypoplastic form, hypo-maturation form, hypo-calcified form, and hypo-maturation/hypoplasia form with taurodontism and 14 subcategories. The diagnosis and classification of amelogenesis imperfecta has traditionally been based on clinical presentation or phenotype and the inheritance pattern. Several genes can be mutated and cause the disease. Millions of genes, possibly more than 10,000 genes produce proteins that regulate synthesis of enamel. Some of the genes and gene products that are likely associated with amelogenesis imperfecta are: amelogenin (AMELX, AMELY genes, ameloblastin (AMBN gene, enamelin (ENAM gene, enamelysin (MMP20 gene, kalikryn 4 (KLK 4 gene, tuftelins (Tuftelin gene, FAM83H (FAM83H gene and WDR72 (WDR72 gene. Particular attention should be given by the dentist in recognition and correlation of phenotypes with genotypes, in order to diagnose quickly and accurately such a possible disease and to prevent or treat it easily and quickly. Modern dentistry should restore these lesions in order to guarantee aesthetics and functionality, usually in collaboration with a group of dentists.

  18. Assessment of working memory in patients with mesial temporal lobe epilepsy associated with unilateral hippocampal sclerosis.

    Science.gov (United States)

    Tudesco, Ivanda de Souza Silva; Vaz, Leonardo José; Mantoan, Marcele Araújo Silva; Belzunces, Erich; Noffs, Maria Helena; Caboclo, Luís Otávio Sales Ferreira; Yacubian, Elza Márcia Targas; Sakamoto, Américo Ceiki; Bueno, Orlando Francisco Amodeo

    2010-07-01

    The aim of the present study was to investigate whether working memory is impaired in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS), a controversial and largely unexplored matter. Twenty subjects with left MTLE-HS, 19 with right MTLE-HS, and 21 control right-handed subjects underwent neuropsychological assessment of episodic and semantic memory, executive functions, and specific working memory components. Left and right epileptogenic foci resulted in impairment of verbal and nonverbal episodic memory (verbal memory deficit greater in left MTLE-HS than in right MTLE-HS). In addition, patients with left MTLE-HS were impaired in learning paired associates, verbal fluency, and Trail Making. No differences were seen in the tests carried out to evaluate the working memory components (except visuospatial short-term memory in right MTLE-HS). In this study we did not detect reliable working memory impairment in patients with MTLE-HS with either a left or right focus in most tasks considered as tests of working memory components. Copyright 2010 Elsevier Inc. All rights reserved.

  19. Psychiatric comorbidity in epilepsy: a study comparing patients with mesial temporal sclerosis and juvenile myoclonic epilepsy.

    Science.gov (United States)

    Filho, Gerardo Maria de Araújo; Rosa, Vivianne Pellegrino; Lin, Katia; Caboclo, Luís Otávio Sales Ferreira; Sakamoto, Américo Ceiki; Yacubian, Elza Márcia Targas

    2008-07-01

    We evaluated the frequency of psychiatric disorders (PDs) in a homogenous series of patients with temporal lobe epilepsy with mesial temporal sclerosis (TLE-MTS), as compared with patients with juvenile myoclonic epilepsy (JME), aiming to determine possible differences in psychiatric diagnoses between these two epileptic syndromes. Data from 170 patients with refractory TLE-MTS and from 100 patients with JME were reviewed and compared. The prevalence of PDs was high in both groups of patients with epilepsy: PDs were present in 85 patients with TLE-MTS (50%) and 49 patients with JME (49%). Among the TLE-MTS group, mood (25.8%), psychotic (15.8%), and anxiety (14.1%) disorders were the most frequent diagnoses, whereas anxiety and mood disorders (23 and 19%, respectively) were the most common among patients with JME. Psychoses were significantly associated with MTS (P<0.01) and anxiety disorders with JME (P<0.05). These findings suggest the existence of an anatomic correlation between PDs and brain structures involved in both epilepsy syndromes.

  20. Effect of seizure on hippocampus in mesial temporal lobe epilepsy and neocortical epilepsy: an MRS study

    International Nuclear Information System (INIS)

    Lee, S.K.; Kim, D.W.; Kim, K.K.; Chung, C.K.; Song, I.C.; Chang, K.H.

    2005-01-01

    This study was performed to evaluate the effect of seizures on the bilateral hippocampus in mesial temporal lobe epilepsy (mTLE) and neocortical epilepsy by single voxel proton magnetic resonance spectroscopy (MRS). Forty-one patients with mTLE having unilateral hippocampal sclerosis and 43 patients with a neocortical epilepsy who underwent subsequent epilepsy surgery were recruited. Ninety-five percent confidence intervals of N-acetyl aspartate/choline (NAA/Cho) and NAA/creatine (NAA/Cr) ratios in 20 healthy control subjects were used as threshold values to determine abnormal NAA/Cho and NAA/Cr. NAA/Cho and NAA/Cr were significantly lower in the ipsilateral hippocampus of mTLE and neocortical epilepsy. Using asymmetry indices for patients with bilaterally abnormal ratios of NAA/Cho and NAA/Cr in addition to using unilateral abnormal ratio, the seizure focus was correctly lateralized in 65.9% of patients with mTLE and 48.8% of neocortical epilepsy patients. Bilateral NAA/Cho abnormality was significantly related to a poor surgical outcome in mTLE. No significant relationship was found between the results of NAA/Cho or NAA/Cr and surgical outcome in neocortical epilepsy. The mean contralateral NAA/Cr ratio of the hippocampus in mTLE was significantly lower in patients with a history of secondary generalized tonic-clonic seizure (SGTCS) than in those without. (orig.)

  1. Uncinate fasciculus fiber tracking in mesial temporal lobe epilepsy. Initial findings

    International Nuclear Information System (INIS)

    Rodrigo, S.; Oppenheim, C.; Meder, J.F.; Chassoux, F.; Golestani, N.; Cointepas, Y.; Poupon, C.; Semah, F.; Mangin, J.F.; Le Bihan, D.

    2007-01-01

    In temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS), ictal discharge spread to the frontal and insulo-perisylvian cortex is commonly observed. The implication of white matter pathways in this propagation has not been investigated. We compared diffusion tensor imaging (DTI) measurements along the uncinate fasciculus (UF), a major tract connecting the frontal and temporal lobes, in patients and controls. Ten right-handed patients referred for intractable TLE due to a right HS were investigated on a 1.5-T MR scanner including a DTI sequence. All patients had interictal fluorodeoxyglucose PET showing an ipsilateral temporal hypometabolism associated with insular and frontal or perisylvian hypometabolism. The controls consisted of ten right-handed healthy subjects. UF fiber tracking was performed, and its fractional anisotropy (FA) values were compared between patients and controls, separately for the right and left UF. The left-minus-right FA UF asymmetry index was computed to test for intergroup differences. Asymmetries were found in the control group with right-greater-than-left FA. This asymmetrical pattern was lost in the patient group. Right FA values were lower in patients with right HS versus controls. Although preliminary, these findings may be related to the preferential pathway of seizure spread from the mesial temporal lobe to frontal and insulo-perisylvian areas. (orig.)

  2. 1H MR spectroscopy in histopathological subgroups of mesial temporal lobe epilepsy

    International Nuclear Information System (INIS)

    Hajek, Milan; Dezortova, Monika; Krsek, Pavel; Komarek, Vladimir; Marusic, Petr; Tomasek, Martin; Krijtova, Hana; Zamecnik, Josef; Kyncl, Martin

    2009-01-01

    The aim of the study was to analyze the lateralizing value of proton magnetic resonance spectroscopy ( 1 H MRS) in histopathologically different subgroups of mesial temporal lobe epilepsies (MTLE) and to correlate results with clinical, MRI and seizure outcome data. A group of 35 patients who underwent resective epilepsy surgery was retrospectively studied. Hippocampal 1 H MR spectra were evaluated. Metabolite concentrations were obtained using LCModel and NAA/Cr, NAA/Cho, NAA/(Cr+Cho), Cho/Cr ratios and coefficients of asymmetry were calculated. MRI correctly lateralized 89% of subjects and 1 H MRS 83%. MRI together with 1 H MRS correctly lateralized 100% of patients. Nineteen subjects had ''classical'' hippocampal sclerosis (HS), whereas the remaining 16 patients had ''mild'' HS. Nineteen patients had histopathologically proven malformation of cortical development (MCD) in the temporal pole; 16 subjects had only HS. No difference in 1 H MRS findings was found between patients in different histopathological subgroups of MTLE. Our results support the hypothesis that 1 H MRS abnormalities do not directly reflect histopathological changes in MTLE patients. Subjects with non-lateralized 1 H MRS abnormalities did not have a worse postoperative seizure outcome. We found no significant impact of contralateral 1 H MRS abnormality on post-surgical seizure outcome. (orig.)

  3. Brain SPECT in mesial temporal lobe epilepsy: comparison between visual analysis and SPM (Statistical Parametric Mapping)

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, Barbara Juarez; Ramos, Celso Dario; Santos, Allan Oliveira dos; Lima, Mariana da Cunha Lopes de; Camargo, Edwaldo Eduardo; Etchebehere, Elba Cristina Sa de Camargo, E-mail: juarezbarbara@hotmail.co [State University of Campinas (UNICAMP), SP (Brazil). School of Medical Sciences. Dept. of Radiology; Min, Li Li; Cendes, Fernando [State University of Campinas (UNICAMP), SP (Brazil). School of Medical Sciences. Dept. of Neurology

    2010-04-15

    Objective: to compare the accuracy of SPM and visual analysis of brain SPECT in patients with mesial temporal lobe epilepsy (MTLE). Method: interictal and ictal SPECTs of 22 patients with MTLE were performed. Visual analysis were performed in interictal (VISUAL(inter)) and ictal (VISUAL(ictal/inter)) studies. SPM analysis consisted of comparing interictal (SPM(inter)) and ictal SPECTs (SPM(ictal)) of each patient to control group and by comparing perfusion of temporal lobes in ictal and interictal studies among themselves (SPM(ictal/inter)). Results: for detection of the epileptogenic focus, the sensitivities were as follows: VISUAL(inter)=68%; VISUAL(ictal/inter)=100%; SPM(inter)=45%; SPM(ictal)=64% and SPM(ictal/inter)=77%. SPM was able to detect more areas of hyperperfusion and hypoperfusion. Conclusion: SPM did not improve the sensitivity to detect epileptogenic focus. However, SPM detected different regions of hypoperfusion and hyperperfusion and is therefore a helpful tool for better understand pathophysiology of seizures in MTLE. (author)

  4. Pathophysiogenesis of Mesial Temporal Lobe Epilepsy: Is Prevention of Damage Antiepileptogenic?

    Science.gov (United States)

    Curia, G.; Lucchi, C.; Vinet, J.; Gualtieri, F.; Marinelli, C.; Torsello, A.; Costantino, L.; Biagini*,, G.

    2014-01-01

    Temporal lobe epilepsy (TLE) is frequently associated with hippocampal sclerosis, possibly caused by a primary brain injury that occurred a long time before the appearance of neurological symptoms. This type of epilepsy is characterized by refractoriness to drug treatment, so to require surgical resection of mesial temporal regions involved in seizure onset. Even this last therapeutic approach may fail in giving relief to patients. Although prevention of hippocampal damage and epileptogenesis after a primary event could be a key innovative approach to TLE, the lack of clear data on the pathophysiological mechanisms leading to TLE does not allow any rational therapy. Here we address the current knowledge on mechanisms supposed to be involved in epileptogenesis, as well as on the possible innovative treatments that may lead to a preventive approach. Besides loss of principal neurons and of specific interneurons, network rearrangement caused by axonal sprouting and neurogenesis are well known phenomena that are integrated by changes in receptor and channel functioning and modifications in other cellular components. In particular, a growing body of evidence from the study of animal models suggests that disruption of vascular and astrocytic components of the blood-brain barrier takes place in injured brain regions such as the hippocampus and piriform cortex. These events may be counteracted by drugs able to prevent damage to the vascular component, as in the case of the growth hormone secretagogue ghrelin and its analogues. A thoroughly investigation on these new pharmacological tools may lead to design effective preventive therapies. PMID:24251566

  5. Uncinate fasciculus fiber tracking in mesial temporal lobe epilepsy. Initial findings

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigo, S.; Oppenheim, C.; Meder, J.F. [Universite Paris-Descartes, Faculte de Medecine, Centre Hospitalier Sainte-Anne, Departement d' Imagerie Morphologique et Fonctionnelle, Paris (France); Chassoux, F. [Universite Paris-Descartes, Faculte de Medecine, Service de Neurochirurgie, Centre Hospitalier Sainte-Anne, Paris (France); Golestani, N.; Cointepas, Y.; Poupon, C.; Semah, F.; Mangin, J.F.; Le Bihan, D. [Service Hospitalier Frederic Joliot, CEA, Orsay (France)

    2007-07-15

    In temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS), ictal discharge spread to the frontal and insulo-perisylvian cortex is commonly observed. The implication of white matter pathways in this propagation has not been investigated. We compared diffusion tensor imaging (DTI) measurements along the uncinate fasciculus (UF), a major tract connecting the frontal and temporal lobes, in patients and controls. Ten right-handed patients referred for intractable TLE due to a right HS were investigated on a 1.5-T MR scanner including a DTI sequence. All patients had interictal fluorodeoxyglucose PET showing an ipsilateral temporal hypometabolism associated with insular and frontal or perisylvian hypometabolism. The controls consisted of ten right-handed healthy subjects. UF fiber tracking was performed, and its fractional anisotropy (FA) values were compared between patients and controls, separately for the right and left UF. The left-minus-right FA UF asymmetry index was computed to test for intergroup differences. Asymmetries were found in the control group with right-greater-than-left FA. This asymmetrical pattern was lost in the patient group. Right FA values were lower in patients with right HS versus controls. Although preliminary, these findings may be related to the preferential pathway of seizure spread from the mesial temporal lobe to frontal and insulo-perisylvian areas. (orig.)

  6. Scale invariance properties of intracerebral EEG improve seizure prediction in mesial temporal lobe epilepsy.

    Directory of Open Access Journals (Sweden)

    Kais Gadhoumi

    Full Text Available Although treatment for epilepsy is available and effective for nearly 70 percent of patients, many remain in need of new therapeutic approaches. Predicting the impending seizures in these patients could significantly enhance their quality of life if the prediction performance is clinically practical. In this study, we investigate the improvement of the performance of a seizure prediction algorithm in 17 patients with mesial temporal lobe epilepsy by means of a novel measure. Scale-free dynamics of the intracerebral EEG are quantified through robust estimates of the scaling exponents--the first cumulants--derived from a wavelet leader and bootstrap based multifractal analysis. The cumulants are investigated for the discriminability between preictal and interictal epochs. The performance of our recently published patient-specific seizure prediction algorithm is then out-of-sample tested on long-lasting data using combinations of cumulants and state similarity measures previously introduced. By using the first cumulant in combination with state similarity measures, up to 13 of 17 patients had seizures predicted above chance with clinically practical levels of sensitivity (80.5% and specificity (25.1% of total time under warning for prediction horizons above 25 min. These results indicate that the scale-free dynamics of the preictal state are different from those of the interictal state. Quantifiers of these dynamics may carry a predictive power that can be used to improve seizure prediction performance.

  7. Effect of seizure on hippocampus in mesial temporal lobe epilepsy and neocortical epilepsy: an MRS study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.K.; Kim, D.W.; Kim, K.K. [Seoul National University College of Medicine, Seoul National University Hospital, Department of Neurology, Chongno ku, Seoul (Korea); Chung, C.K. [Seoul National University College of Medicine, Seoul National University Hospital, Department of Neurosurgery, Chongno ku, Seoul (Korea); Song, I.C.; Chang, K.H. [Seoul National University College of Medicine, Seoul National University Hospital, Department of Radiology, Chongno ku, Seoul (Korea)

    2005-12-01

    This study was performed to evaluate the effect of seizures on the bilateral hippocampus in mesial temporal lobe epilepsy (mTLE) and neocortical epilepsy by single voxel proton magnetic resonance spectroscopy (MRS). Forty-one patients with mTLE having unilateral hippocampal sclerosis and 43 patients with a neocortical epilepsy who underwent subsequent epilepsy surgery were recruited. Ninety-five percent confidence intervals of N-acetyl aspartate/choline (NAA/Cho) and NAA/creatine (NAA/Cr) ratios in 20 healthy control subjects were used as threshold values to determine abnormal NAA/Cho and NAA/Cr. NAA/Cho and NAA/Cr were significantly lower in the ipsilateral hippocampus of mTLE and neocortical epilepsy. Using asymmetry indices for patients with bilaterally abnormal ratios of NAA/Cho and NAA/Cr in addition to using unilateral abnormal ratio, the seizure focus was correctly lateralized in 65.9% of patients with mTLE and 48.8% of neocortical epilepsy patients. Bilateral NAA/Cho abnormality was significantly related to a poor surgical outcome in mTLE. No significant relationship was found between the results of NAA/Cho or NAA/Cr and surgical outcome in neocortical epilepsy. The mean contralateral NAA/Cr ratio of the hippocampus in mTLE was significantly lower in patients with a history of secondary generalized tonic-clonic seizure (SGTCS) than in those without. (orig.)

  8. Spatial memory for asymmetrical dot locations predicts lateralization among patients with presurgical mesial temporal lobe epilepsy.

    Science.gov (United States)

    Brown, Franklin C; Hirsch, Lawrence J; Spencer, Dennis D

    2015-11-01

    This study examined the ability of an asymmetrical dot location memory test (Brown Location Test, BLT) and two verbal memory tests (Verbal Selective Reminding Test (VSRT) and California Verbal Learning Test, Second Edition (CVLT-II)) to correctly lateralize left (LTLE) or right (RTLE) mesial temporal lobe epilepsy that was confirmed with video-EEG. Subjects consisted of 16 patients with medically refractory RTLE and 13 patients with medically refractory LTLE who were left hemisphere language dominant. Positive predictive values for lateralizing TLE correctly were 87.5% for the BLT, 72.7% for the VSRT, and 80% for the CVLT-II. Binary logistic regression indicated that the BLT alone correctly classified 76.9% of patients with left temporal lobe epilepsy and 87.5% of patients with right temporal lobe epilepsy. Inclusion of the verbal memory tests improved this to 92.3% of patients with left temporal lobe epilepsy and 100% correct classification of patients with right temporal lobe epilepsy. Though of a limited sample size, this study suggests that the BLT alone provides strong laterality information which improves with the addition of verbal memory tests. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. {sup 1}H MR spectroscopy in histopathological subgroups of mesial temporal lobe epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Hajek, Milan; Dezortova, Monika [Institute for Clinical and Experimental Medicine, MR Unit, Department of Diagnostic and Interventional Radiology, Prague (Czech Republic); Krsek, Pavel; Komarek, Vladimir [Charles University, Department of Pediatric Neurology, Prague 5 (Czech Republic); Marusic, Petr; Tomasek, Martin; Krijtova, Hana [Charles University, Department of Neurology, Prague (Czech Republic); Zamecnik, Josef [Charles University, Department of Pathology and Molecular Medicine, Prague (Czech Republic); Kyncl, Martin [Charles University, Department of Radiology, Prague (Czech Republic)

    2009-02-15

    The aim of the study was to analyze the lateralizing value of proton magnetic resonance spectroscopy ({sup 1}H MRS) in histopathologically different subgroups of mesial temporal lobe epilepsies (MTLE) and to correlate results with clinical, MRI and seizure outcome data. A group of 35 patients who underwent resective epilepsy surgery was retrospectively studied. Hippocampal {sup 1}H MR spectra were evaluated. Metabolite concentrations were obtained using LCModel and NAA/Cr, NAA/Cho, NAA/(Cr+Cho), Cho/Cr ratios and coefficients of asymmetry were calculated. MRI correctly lateralized 89% of subjects and {sup 1}H MRS 83%. MRI together with {sup 1}H MRS correctly lateralized 100% of patients. Nineteen subjects had 'classical' hippocampal sclerosis (HS), whereas the remaining 16 patients had 'mild' HS. Nineteen patients had histopathologically proven malformation of cortical development (MCD) in the temporal pole; 16 subjects had only HS. No difference in {sup 1}H MRS findings was found between patients in different histopathological subgroups of MTLE. Our results support the hypothesis that {sup 1}H MRS abnormalities do not directly reflect histopathological changes in MTLE patients. Subjects with non-lateralized {sup 1}H MRS abnormalities did not have a worse postoperative seizure outcome. We found no significant impact of contralateral {sup 1}H MRS abnormality on post-surgical seizure outcome. (orig.)

  10. Asymmetrical hippocampal connectivity in mesial temporal lobe epilepsy: evidence from resting state fMRI

    Directory of Open Access Journals (Sweden)

    Castellano Gabriela

    2010-06-01

    Full Text Available Abstract Background Mesial temporal lobe epilepsy (MTLE, the most common type of focal epilepsy in adults, is often caused by hippocampal sclerosis (HS. Patients with HS usually present memory dysfunction, which is material-specific according to the hemisphere involved and has been correlated to the degree of HS as measured by postoperative histopathology as well as by the degree of hippocampal atrophy on magnetic resonance imaging (MRI. Verbal memory is mostly affected by left-sided HS, whereas visuo-spatial memory is more affected by right HS. Some of these impairments may be related to abnormalities of the network in which individual hippocampus takes part. Functional connectivity can play an important role to understand how the hippocampi interact with other brain areas. It can be estimated via functional Magnetic Resonance Imaging (fMRI resting state experiments by evaluating patterns of functional networks. In this study, we investigated the functional connectivity patterns of 9 control subjects, 9 patients with right MTLE and 9 patients with left MTLE. Results We detected differences in functional connectivity within and between hippocampi in patients with unilateral MTLE associated with ipsilateral HS by resting state fMRI. Functional connectivity resulted to be more impaired ipsilateral to the seizure focus in both patient groups when compared to control subjects. This effect was even more pronounced for the left MTLE group. Conclusions The findings presented here suggest that left HS causes more reduction of functional connectivity than right HS in subjects with left hemisphere dominance for language.

  11. Mesial temporal lobe epilepsy lateralization using SPHARM-based features of hippocampus and SVM

    Science.gov (United States)

    Esmaeilzadeh, Mohammad; Soltanian-Zadeh, Hamid; Jafari-Khouzani, Kourosh

    2012-02-01

    This paper improves the Lateralization (identification of the epileptogenic hippocampus) accuracy in Mesial Temporal Lobe Epilepsy (mTLE). In patients with this kind of epilepsy, usually one of the brain's hippocampi is the focus of the epileptic seizures, and resection of the seizure focus is the ultimate treatment to control or reduce the seizures. Moreover, the epileptogenic hippocampus is prone to shrinkage and deformation; therefore, shape analysis of the hippocampus is advantageous in the preoperative assessment for the Lateralization. The method utilized for shape analysis is the Spherical Harmonics (SPHARM). In this method, the shape of interest is decomposed using a set of bases functions and the obtained coefficients of expansion are the features describing the shape. To perform shape comparison and analysis, some pre- and post-processing steps such as "alignment of different subjects' hippocampi" and the "reduction of feature-space dimension" are required. To this end, first order ellipsoid is used for alignment. For dimension reduction, we propose to keep only the SPHARM coefficients with maximum conformity to the hippocampus shape. Then, using these coefficients of normal and epileptic subjects along with 3D invariants, specific lateralization indices are proposed. Consequently, the 1536 SPHARM coefficients of each subject are summarized into 3 indices, where for each index the negative (positive) value shows that the left (right) hippocampus is deformed (diseased). Employing these indices, the best achieved lateralization accuracy for clustering and classification algorithms are 85% and 92%, respectively. This is a significant improvement compared to the conventional volumetric method.

  12. Electrophysiological resting-state biomarker for diagnosing mesial temporal lobe epilepsy with hippocampal sclerosis.

    Science.gov (United States)

    Jin, Seung-Hyun; Chung, Chun Kee

    2017-01-01

    The main aim of the present study was to evaluate whether resting-state functional connectivity of magnetoencephalography (MEG) signals can differentiate patients with mesial temporal lobe epilepsy (MTLE) from healthy controls (HC) and can differentiate between right and left MTLE as a diagnostic biomarker. To this end, a support vector machine (SVM) method among various machine learning algorithms was employed. We compared resting-state functional networks between 46 MTLE (right MTLE=23; left MTLE=23) patients with histologically proven HS who were free of seizure after surgery, and 46 HC. The optimal SVM group classifier distinguished MTLE patients with a mean accuracy of 95.1% (sensitivity=95.8%; specificity=94.3%). Increased connectivity including the right posterior cingulate gyrus and decreased connectivity including at least one sensory-related resting-state network were key features reflecting the differences between MTLE patients and HC. The optimal SVM model distinguished between right and left MTLE patients with a mean accuracy of 76.2% (sensitivity=76.0%; specificity=76.5%). We showed the potential of electrophysiological resting-state functional connectivity, which reflects brain network reorganization in MTLE patients, as a possible diagnostic biomarker to differentiate MTLE patients from HC and differentiate between right and left MTLE patients. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Brain SPECT in mesial temporal lobe epilepsy: comparison between visual analysis and SPM (Statistical Parametric Mapping)

    International Nuclear Information System (INIS)

    Amorim, Barbara Juarez; Ramos, Celso Dario; Santos, Allan Oliveira dos; Lima, Mariana da Cunha Lopes de; Camargo, Edwaldo Eduardo; Etchebehere, Elba Cristina Sa de Camargo; Min, Li Li; Cendes, Fernando

    2010-01-01

    Objective: to compare the accuracy of SPM and visual analysis of brain SPECT in patients with mesial temporal lobe epilepsy (MTLE). Method: interictal and ictal SPECTs of 22 patients with MTLE were performed. Visual analysis were performed in interictal (VISUAL(inter)) and ictal (VISUAL(ictal/inter)) studies. SPM analysis consisted of comparing interictal (SPM(inter)) and ictal SPECTs (SPM(ictal)) of each patient to control group and by comparing perfusion of temporal lobes in ictal and interictal studies among themselves (SPM(ictal/inter)). Results: for detection of the epileptogenic focus, the sensitivities were as follows: VISUAL(inter)=68%; VISUAL(ictal/inter)=100%; SPM(inter)=45%; SPM(ictal)=64% and SPM(ictal/inter)=77%. SPM was able to detect more areas of hyperperfusion and hypoperfusion. Conclusion: SPM did not improve the sensitivity to detect epileptogenic focus. However, SPM detected different regions of hypoperfusion and hyperperfusion and is therefore a helpful tool for better understand pathophysiology of seizures in MTLE. (author)

  14. Perspectives on treatment options for mesial temporal lobe epilepsy with hippocampal sclerosis.

    Science.gov (United States)

    Palleria, Caterina; Coppola, Antonietta; Citraro, Rita; Del Gaudio, Luigi; Striano, Salvatore; De Sarro, Giovambattista; Russo, Emilio

    2015-01-01

    Mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) is a syndrome that is often refractory to drug treatment. The effects on specific syndromes are not currently available from the pre-marketing clinical development of new AEDs; this does not allow the prediction of whether new drugs will be more effective in the treatment of some patients. We have reviewed all the existing literature relevant to the understanding of a potential effectiveness in MTLE-HS patients for the latest AEDs, namely brivaracetam, eslicarbazepine, lacosamide, perampanel and retigabine also including the most relevant clinical data and a brief description of their pharmacological profile. Records were identified using predefined search criteria using electronic databases (e.g., PubMed, Cochrane Library Database of Systematic Reviews). Primary peer-reviewed articles published up to the 15 June 2015 were included. All the drugs considered have the potential to be effective in the treatment of MTLE-HS; in fact, they possess proven efficacy in animal models; currently considered valuable tools for predicting drug efficacy in TLE. Furthermore, for some of these (e.g., lacosamide and eslicarbazepine) data are already available from post-marketing studies while brivaracetam acting on SV2A like levetiracetam might have the same potential effectiveness with the possibility to be more efficacious considering its ability to inhibit voltage gated sodium channels; finally, perampanel and retigabine are very effective drugs in animal models of TLE.

  15. Enamel Defects Reflect Perinatal Exposure to Bisphenol A

    Science.gov (United States)

    Jedeon, Katia; De la Dure-Molla, Muriel; Brookes, Steven J.; Loiodice, Sophia; Marciano, Clémence; Kirkham, Jennifer; Canivenc-Lavier, Marie-Chantal; Boudalia, Sofiane; Bergès, Raymond; Harada, Hidemitsu; Berdal, Ariane; Babajko, Sylvie

    2014-01-01

    Endocrine-disrupting chemicals (EDCs), including bisphenol A (BPA), are environmental ubiquitous pollutants and associated with a growing health concern. Anecdotally, molar incisor hypomineralization (MIH) is increasing concurrently with EDC-related conditions, which has led us to investigate the effect of BPA on amelogenesis. Rats were exposed daily to BPA from conception until day 30 or 100. At day 30, BPA-affected enamel exhibited hypomineralization similar to human MIH. Scanning electron microscopy and elemental analysis revealed an abnormal accumulation of organic material in erupted enamel. BPA-affected enamel had an abnormal accumulation of exogenous albumin in the maturation stage. Quantitative real-timePCR, Western blotting, and luciferase reporter assays revealed increased expression of enamelin but decreased expression of kallikrein 4 (protease essential for removing enamel proteins) via transcriptional regulation. Data suggest that BPA exerts its effects on amelogenesis by disrupting normal protein removal from the enamel matrix. Interestingly, in 100-day-old rats, erupting incisor enamel was normal, suggesting amelogenesis is only sensitive to MIH-causing agents during a specific time window during development (as reported for human MIH). The present work documents the first experimental model that replicates MIH and presents BPA as a potential causative agent of MIH. Because human enamel defects are irreversible, MIH may provide an easily accessible marker for reporting early EDC exposure in humans. PMID:23764278

  16. Enamel microabrasion: An overview of clinical and scientific considerations

    Science.gov (United States)

    Pini, Núbia Inocencya Pavesi; Sundfeld-Neto, Daniel; Aguiar, Flavio Henrique Baggio; Sundfeld, Renato Herman; Martins, Luis Roberto Marcondes; Lovadino, José Roberto; Lima, Débora Alves Nunes Leite

    2015-01-01

    Superficial stains and irregularities of the enamel are generally what prompt patients to seek dental intervention to improve their smile. These stains or defects may be due to hypoplasia, amelogenesis imperfecta, mineralized white spots, or fluorosis, for which enamel microabrasion is primarily indicated. Enamel microabrasion involves the use of acidic and abrasive agents, such as with 37% phosphoric acid and pumice or 6% hydrochloric acid and silica, applied to the altered enamel surface with mechanical pressure from a rubber cup coupled to a rotatory mandrel of a low-rotation micromotor. If necessary, this treatment can be safely combined with bleaching for better esthetic results. Recent studies show that microabrasion is a conservative treatment when the enamel wear is minimal and clinically imperceptible. The most important factor contributing to the success of enamel microabrasion is the depth of the defect, as deeper, opaque stains, such as those resulting from hypoplasia, cannot be resolved with microabrasion, and require a restorative approach. Surface enamel alterations that result from microabrasion, such as roughness and microhardness, are easily restored by saliva. Clinical studies support the efficacy and longevity of this safe and minimally invasive treatment. The present article presents the clinical and scientific aspects concerning the microabrasion technique, and discusses the indications for and effects of the treatment, including recent works describing microscopic and clinical evaluations. PMID:25610848

  17. DESIGN AND APPLICATION OF TRANSPARENT AND TRANSLUCENT ENAMELS ON ALUMINUM

    Directory of Open Access Journals (Sweden)

    H. AHMADI MOGHADDAM

    2012-09-01

    Full Text Available Transparent and opaque glass enamels for aluminum plates were designed with a minimum or with no heavy atom oxides such as lead and bismuth oxides. The thermal properties of the enamels were studied by DTA and their stability as measured by the difference of glass transition and crystallization onset temperatures was determined. Bending and rapid deformation (impact tests indicated the interfacial adhesion. The enamel/aluminum interfacial qualities were viewed and examined by scanning electron microscopy (SEM. A large amount of NaF and P2O5 in their formulation created opaque enamels. The three methods of melt dipping, pouring, and sintering were used to apply layers of enamels on aluminum plates. The novelty of the pouring and spreading method and its advantages over other methods, were in the use of lower stability and higher melting point enamels, without thermally/mechanically damaging the aluminum. Observations suggested that the interfacial contact and adhesion properties were good, particularly with the transparent or glassy state enamels.

  18. Development of fluorapatite cement for dental enamel defects repair.

    Science.gov (United States)

    Wei, Jie; Wang, Jiecheng; Shan, Wenpeng; Liu, Xiaochen; Ma, Jian; Liu, Changsheng; Fang, Jing; Wei, Shicheng

    2011-06-01

    In order to restore the badly carious lesion of human dental enamel, a crystalline paste of fluoride substituted apatite cement was synthesized by using the mixture of tetracalcium phosphate (TTCP), dicalcium phosphate anhydrous (DCPA) and ammonium fluoride. The apatite cement paste could be directly filled into the enamel defects (cavities) to repair damaged dental enamel. The results indicated that the hardened cement was fluorapatite [Ca(10)(PO(4))(6)F(2), FA] with calcium to phosphorus atom molar ratio (Ca/P) of 1.67 and Ca/F ratio of 5. The solubility of FA cement in Tris-HCl solution (pH = 5) was slightly lower than the natural enamel, indicating the FA cement was much insensitive to the weakly acidic solutions. The FA cement was tightly combined with the enamel surface, and there was no obvious difference of the hardness between the FA cement and natural enamel. The extracts of FA cement caused no cytotoxicity on L929 cells, which satisfied the relevant criterion on dental biomaterials, revealing good cytocompatibility. In addition, the results showed that the FA cement had good mechanical strength, hydrophilicity, and anti-bacterial adhesion properties. The study suggested that using FA cement was simple and promising approach to effectively and conveniently restore enamel defects.

  19. Spatial distribution of the human enamel fracture toughness with aging.

    Science.gov (United States)

    Zheng, Qinghua; Xu, Haiping; Song, Fan; Zhang, Lan; Zhou, Xuedong; Shao, Yingfeng; Huang, Dingming

    2013-10-01

    A better understanding of the fracture toughness (KIC) of human enamel and the changes induced by aging is important for the clinical treatment of teeth cracks and fractures. We conducted microindentation tests and chemical content measurements on molar teeth from "young" (18 ≤ age ≤ 25) and "old" (55 ≤ age) patients. The KIC and the mineral contents (calcium and phosphorus) in the outer, the middle, and the inner enamel layers within the cuspal and the intercuspal regions of the crown were measured through the Vickers toughness test and Energy Dispersive X-Ray Spectroscopy (EDS), respectively. The elastic modulus used for the KIC calculation was measured through atomic force microscope (AFM)-based nanoindentation tests. In the outer enamel layer, two direction-specific values of the KIC were calculated separately (direction I, crack running parallel to the occlusal surface; direction II, perpendicular to direction I). The mean KIC of the outer enamel layer was lower than that of the internal layers (penamel layer, old enamel has a lower KIC, II and higher mineral contents than young enamel (penamel surface becomes more prone to cracks with aging partly due to the reduction in the interprismatic organic matrix observed with the maturation of enamel. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. 78 FR 13869 - Puget Sound Energy, Inc.; Puget Sound Energy, Inc.; Puget Sound Energy, Inc.; Puget Sound Energy...

    Science.gov (United States)

    2013-03-01

    ...-123-LNG; 12-128-NG; 12-148-NG; 12- 158-NG] Puget Sound Energy, Inc.; Puget Sound Energy, Inc.; Puget Sound Energy, Inc.; Puget Sound Energy, Inc.; Puget Sound Energy, Inc.; CE FLNG, LLC; Consolidated...-NG Puget Sound Energy, Inc Order granting long- term authority to import/export natural gas from/to...

  1. Microstructure and hardness of bovine enamel in roselle extract solution

    Science.gov (United States)

    Dame, M. T.; Noerdin, A.; Indrani, D. J.

    2017-08-01

    The aim of this study was to analyze the effect of roselle extract solution on the microstructure and hardness of bovine enamel. Ten bovine teeth and a 5% concentration of roselle extract solution were prepared. Immersions of each bovine tooth in roselle extract solution were conducted up to 60 minutes. The bovine enamel surface was characterized in hardness and microscopy. It was apparent that the initial hardness was 328 KHN, and after immersion in 15 and 60 min, the values decrease to 57.4 KHN and 11 KHN, respectively. Scanning electron microscopy (SEM) revealed changes in enamel rods after immersion in the roselle extract solution.

  2. Chromatographic separation of alkaline phosphatase from dental enamel

    DEFF Research Database (Denmark)

    Moe, D; Kirkeby, S; Salling, E

    1989-01-01

    Alkaline phosphatase (AP) was prepared from partly mineralized bovine enamel by extraction in phosphate buffer, centrifugation and various chromatographic techniques. Chromatofocusing showed that the enamel enzyme possessed five isoelectric points at the acid pH level ranging from pH 5.7 to pH 4.......4. Three enzyme peaks were eluted using low pressure chromatography with a Bio-gel column. With a HPLC gel filtration column the separation of the enamel extract resulted in only one peak with AP activity. The fractions of this peak were used to produce an antibody against bovine AP....

  3. In vitro study of hydroxy apatite and enamel powder fused in human enamel by Nd:YAG laser

    International Nuclear Information System (INIS)

    Ferrreira, Marcus Vinicius Lucas

    2000-01-01

    The aim of this study was to evaluate the effects of pulsed Nd:YAG (1064 nm) laser irradiation on hydroxyapatite and enamel powder fusion. This laser beam is not well absorbed by this two compounds for this reason they were mixed with vegetal coal to increase the absorption of the laser beam. Fifteen enamel flat surfaces and six occlusal enamel surfaces were prepared with three different substances: hydroxyapatite mixed with vegetal coal (3:1 in weigh); enamel powder mixed with vegetal coal (3:1 in weigh); vegetal coal. The occlusal surfaces were utilized to determine if the compounds could seal pits and fissures. Flat surfaces were utilized to determine fusion of hydroxyapatite and enamel powder. All samples were irradiated with Nd:YAG laser with the parameters: 80 mJ, 15 Hz, 1,2 W, 100 μs pulse-width, 131,1 J/cm 2 . Laser beam was delivered to the samples with a 300 μm diameter fiber optic. Morphology of the irradiated surfaces were examined by scanning electron microscopy (SEM). The compounds with hydroxyapatite and enamel powder were fused to enamel surfaces. Only partial pits and fissures sealing could be observed. (author)

  4. Type VII Collagen is Enriched in the Enamel Organic Matrix Associated with the Dentin-Enamel Junction of Mature Human Teeth

    OpenAIRE

    McGuire, Jacob D.; Walker, Mary P.; Mousa, Ahmad; Wang, Yong; Gorski, Jeff P.

    2014-01-01

    The inner enamel region of erupted teeth is known to exhibit higher fracture toughness and crack growth resistance than bulk phase enamel. However, an explanation for this behavior has been hampered by the lack of compositional information for the residual enamel organic matrix. Since enamel-forming ameloblasts are known to express type VII collagen and type VII collagen null mice display abnormal amelogenesis, the aim of this study was to determine whether type VII collagen is a component of...

  5. Sound a very short introduction

    CERN Document Server

    Goldsmith, Mike

    2015-01-01

    Sound is integral to how we experience the world, in the form of noise as well as music. But what is sound? What is the physical basis of pitch and harmony? And how are sound waves exploited in musical instruments? Sound: A Very Short Introduction looks at the science of sound and the behaviour of sound waves with their different frequencies. It also explores sound in different contexts, covering the audible and inaudible, sound underground and underwater, acoustic and electronic sound, and hearing in humans and animals. It concludes with the problem of sound out of place—noise and its reduction.

  6. Sound Insulation between Dwellings

    DEFF Research Database (Denmark)

    Rasmussen, Birgit

    2011-01-01

    Regulatory sound insulation requirements for dwellings exist in more than 30 countries in Europe. In some countries, requirements have existed since the 1950s. Findings from comparative studies show that sound insulation descriptors and requirements represent a high degree of diversity...... and initiate – where needed – improvement of sound insulation of new and existing dwellings in Europe to the benefit of the inhabitants and the society. A European COST Action TU0901 "Integrating and Harmonizing Sound Insulation Aspects in Sustainable Urban Housing Constructions", has been established and runs...... 2009-2013. The main objectives of TU0901 are to prepare proposals for harmonized sound insulation descriptors and for a European sound classification scheme with a number of quality classes for dwellings. Findings from the studies provide input for the discussions in COST TU0901. Data collected from 24...

  7. Functions of KLK4 and MMP-20 in dental enamel formation

    Science.gov (United States)

    Lu, Yuhe; Papagerakis, Petros; Yamakoshi, Yasuo; Hu, Jan C-C.; Bartlett, John D.; Simmer, James P.

    2009-01-01

    Two proteases are secreted into the enamel matrix of developing teeth. The early protease is enamelysin (MMP-20). The late protease is kallikrein 4 (KLK4). Mutations in MMP20 and KLK4 both cause autosomal recessive amelogenesis imperfecta, a condition featuring soft, porous enamel containing residual protein. MMP-20 is secreted along with enamel proteins by secretory stage ameloblasts. Enamel protein cleavage products accumulate in the space between the crystal ribbons, helping to support them. MMP-20 steadily cleaves accumulated enamel proteins, so their concentration decreases with depth. Kallikrein 4 is secreted by transition and maturation stage ameloblasts. KLK4 aggressively degrades the retained organic matrix following the termination of enamel protein secretion. The principle functions of MMP-20 and KLK4 in dental enamel formation are to facilitate the orderly replacement of organic matrix with mineral, generating an enamel layer that is harder, less porous, and unstained by retained enamel proteins. PMID:18627287

  8. The velocity of sound

    International Nuclear Information System (INIS)

    Beyer, R.T.

    1985-01-01

    The paper reviews the work carried out on the velocity of sound in liquid alkali metals. The experimental methods to determine the velocity measurements are described. Tables are presented of reported data on the velocity of sound in lithium, sodium, potassium, rubidium and caesium. A formula is given for alkali metals, in which the sound velocity is a function of shear viscosity, atomic mass and atomic volume. (U.K.)

  9. Glass enamel and glass-ceramic coatings for chemical apparatus

    International Nuclear Information System (INIS)

    Es'kov, A.S.; Oleinik, M.I.; Shabrova, E.A.

    1984-01-01

    Among the known anticorrosion coatings used in chemical engineering, glass enamel base coatings are distinguished by such advantages as a high degree of continuity and chemical resistance. The paper describes basic principles for the creation of acid and alkali resistant glass enamel and ceramic coatings for chemical apparatus. As the result of investgations, glass enamel coatings with increased electrical conductivity and also experimental production compositions of chemical, temperature and radiation resistant coatings for protection of chemical equipment of 12Kh18N10T stainless steel have been developed. The coatings have successfully passed testing under service conditions. A new type of coating is short-term glass enamel, which may be recommended for use in chemical machinery manufacturing and other branches of industry in oxidation-free heating and forming of stainless steels

  10. Abrasive wear of enamel by bioactive glass-based toothpastes.

    Science.gov (United States)

    Mahmood, Asad; Mneimne, Mohammed; Zou, Li Fong; Hill, Robert G; Gillam, David G

    2014-10-01

    To determine the abrasivity of a 45S5 bioactive glass based toothpaste on enamel as a function of the particle size and shape of the glass. 45S5 glass was synthesized ground and sieved to give various particle sized fractions toothpastes and their tooth brush abrasivity measured according to BS EN ISO11609 methodology. Enamel loss increased with increasing particle size. The percussion milled powder exhibited particles that had sharp edges and the pastes were significantly more abrasive than the pastes made with round ball milled powders. One interesting observation made during the present study was that there was preferential wear of the enamel at the dentin-enamel junction (DEJ), particularly with the coarse particle sized pastes.

  11. Geographic Variations in the EPR Spectrum of Tooth Enamel

    International Nuclear Information System (INIS)

    Romanyukha, A.A.; Hayes, R.B.; Haskell, E.H.; Kenner, G.H.

    1999-01-01

    The presence of stable radiation-induced radicals in the mineral component of tooth enamel allows use of this material as a biological dosemeter. Estimation of the dose absorbed in tooth enamel can be done by EPR. Generally, for the purpose of dose reconstruction, the EPR spectrum of tooth enamel is interpreted in terms of two main components. The first is a broad background signal often called the native signal centered at a g value of 2.0045. The origin of this signal is not precisely known. The second main component in the tooth enamel spectrum is purely radiation induced and can be used for retrospective dosimetry. Internal structure of the native signal and variations of its amplitude and linewidth were investigated for the samples prepared from modern teeth obtained from different geographic locations (USA and Russia). Possible reasons for the variations observed are discussed as are the potential effects of the variations on the reliability of dose estimation. (author)

  12. Protection of enamel surfaces in the oral cavity

    DEFF Research Database (Denmark)

    Lazovic, Maja Bruvo

    The two main diseases that can affect the tooth enamel are dental caries and dental erosion, which both are caused by exposure of the enamel surfaces to acids. In the case of dental caries, acids from bacterial metabolism cause chemical dissolution of the tooth surface, whereas acids from drinks...... and foodstuffs or gastric juice can cause dental erosion. During a lifetime the enamel surface is also exposed to fluids that can have protective effects against dental caries and erosion such as saliva, various foodstuffs, drinking water and many types of drinks. However, little is still known about simple...... inorganic interactions between different fluids and dental caries and little is also known about which saliva proteins are able to protect the enamel surface against dental erosion. Therefore, the overall aim of this thesis was to examine simple inorganic and protein related protective effects with dental...

  13. In phantom dosimetric response of tooth enamel to neutrons

    International Nuclear Information System (INIS)

    Fattibene, P.; Angelone, M.; Pillon, M.; De Coste, V.

    2004-01-01

    Electron Paramagnetic Resonance dosimetry based on tooth enamel has one important application in dose reconstruction of nuclear plant workers, where the contribution of neutrons to individual dose is often important. Evaluation of tooth enamel response to neutrons is thus an important goal. A few experimental data at thermal and fast neutron energies are available. A first evaluation of the tooth enamel relative response to 60 Co in monoenergetic neutron flux of 2.8 and of 14 MeV, published elsewhere, has provided results apparently non-consistent with the results obtained at lower and higher energies. A comparison of those results in the 2.8 and 14 MeV beams with those available in the literature for other beams is reported and possible reasons for incongruities are discussed. Dose conversion factors of enamel to the water and air are also calculated and reported. (authors)

  14. Femtosecond laser etching of dental enamel for bracket bonding.

    Science.gov (United States)

    Kabas, Ayse Sena; Ersoy, Tansu; Gülsoy, Murat; Akturk, Selcuk

    2013-09-01

    The aim is to investigate femtosecond laser ablation as an alternative method for enamel etching used before bonding orthodontic brackets. A focused laser beam is scanned over enamel within the area of bonding in a saw tooth pattern with a varying number of lines. After patterning, ceramic brackets are bonded and bonding quality of the proposed technique is measured by a universal testing machine. The results are compared to the conventional acid etching method. Results show that bonding strength is a function of laser average power and the density of the ablated lines. Intrapulpal temperature changes are also recorded and observed minimal effects are observed. Enamel surface of the samples is investigated microscopically and no signs of damage or cracking are observed. In conclusion, femtosecond laser exposure on enamel surface yields controllable patterns that provide efficient bonding strength with less removal of dental tissue than conventional acid-etching technique.

  15. Large scale study of tooth enamel

    International Nuclear Information System (INIS)

    Bodart, F.; Deconninck, G.; Martin, M.T.

    Human tooth enamel contains traces of foreign elements. The presence of these elements is related to the history and the environment of the human body and can be considered as the signature of perturbations which occur during the growth of a tooth. A map of the distribution of these traces on a large scale sample of the population will constitute a reference for further investigations of environmental effects. On hundred eighty samples of teeth were first analyzed using PIXE, backscattering and nuclear reaction techniques. The results were analyzed using statistical methods. Correlations between O, F, Na, P, Ca, Mn, Fe, Cu, Zn, Pb and Sr were observed and cluster analysis was in progress. The techniques described in the present work have been developed in order to establish a method for the exploration of very large samples of the Belgian population. (author)

  16. Relationship between enamel bond fatigue durability and surface free-energy characteristics with universal adhesives.

    Science.gov (United States)

    Nagura, Yuko; Tsujimoto, Akimasa; Barkmeier, Wayne W; Watanabe, Hidehiko; Johnson, William W; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

    2018-04-01

    The relationship between enamel bond fatigue durability and surface free-energy characteristics with universal adhesives was investigated. The initial shear bond strengths and shear fatigue strengths of five universal adhesives to enamel were determined with and without phosphoric acid pre-etching. The surface free-energy characteristics of adhesive-treated enamel with and without pre-etching were also determined. The initial shear bond strength and shear fatigue strength of universal adhesive to pre-etched enamel were higher than those to ground enamel. The initial shear bond strength and shear fatigue strength of universal adhesive to pre-etched enamel were material dependent, unlike those to ground enamel. The surface free-energy of the solid (γ S ) and the hydrogen-bonding force (γSh) of universal adhesive-treated enamel were different depending on the adhesive, regardless of the presence or absence of pre-etching. The bond fatigue durability of universal adhesives was higher to pre-etched enamel than to ground enamel. In addition, the bond fatigue durability to pre-etched enamel was material dependent, unlike that to ground enamel. The surface free-energy characteristics of universal adhesive-treated enamel were influenced by the adhesive type, regardless of the presence or absence of pre-etching. The surface free-energy characteristics of universal adhesive-treated enamel were related to the results of the bond fatigue durability. © 2018 Eur J Oral Sci.

  17. Analysis of enamel development using murine model systems: approaches and limitations.

    Directory of Open Access Journals (Sweden)

    Megan K Pugach

    2014-09-01

    Full Text Available A primary goal of enamel research is to understand and potentially treat or prevent enamel defects related to amelogenesis imperfecta (AI. Rodents are ideal models to assist our understanding of how enamel is formed because they are easily genetically modified, and their continuously erupting incisors display all stages of enamel development and mineralization. While numerous methods have been developed to generate and analyze genetically modified rodent enamel, it is crucial to understand the limitations and challenges associated with these methods in order to draw appropriate conclusions that can be applied translationally, to AI patient care. We have highlighted methods involved in generating and analyzing rodent enamel and potential approaches to overcoming limitations of these methods: 1 generating transgenic, knockout and knockin mouse models, and 2 analyzing rodent enamel mineral density and functional properties (structure, mechanics of mature enamel. There is a need for a standardized workflow to analyze enamel phenotypes in rodent models so that investigators can compare data from different studies. These methods include analyses of gene and protein expression, developing enamel histology, enamel pigment, degree of mineralization, enamel structure and mechanical properties. Standardization of these methods with regard to stage of enamel development and sample preparation is crucial, and ideally investigators can use correlative and complementary techniques with the understanding that developing mouse enamel is dynamic and complex.

  18. Does the patient's hand hold the key to preventing secondary generalization in mesial temporal lobe epilepsy?

    Science.gov (United States)

    Uchida, Carina Gonçalves Pedroso; Barsottini, Orlando Graziani Povoas; Caboclo, Luís Otávio Sales Ferreira; de Araújo Filho, Gerardo Maria; Centeno, Ricardo Silva; Carrete, Henrique; Yacubian, Elza Márcia Targas

    2013-07-01

    This study aimed to analyze the impact of ictal dystonic posturing (DP) in postoperative seizure outcome and to assess the influence of DP in generalized tonic-clonic seizure (GTCS) occurrence during video-EEG monitoring of patients with temporal lobe epilepsy with mesial temporal sclerosis. The impact of DP on surgical outcome remains controversial. Moreover, DP has been recently associated with brain networks avoiding GTCS occurrence. Five hundred twenty-seven seizures of 171 patients who were submitted to standard anterior temporal lobectomy (ATL) between 2002 and 2010, with at least one year of post-surgical follow-up, were retrospectively analyzed and classified as with or without DP and as evolving or not to GTCS. The ictal semiologic correlates of DP, timing elapsed since precedent seizure and antiepileptic drug (AED) intake before each seizure were evaluated. Seizure outcome after ATL was assessed according to Engel's scale. Fifty-eight out of 171 patients (34%) exhibited ictal DP, of which 91.5% were always unilateral and contralateral to the operated side. DP was related to shorter seizures (p=0.007) and a much lower likelihood of the seizure evolving to GTCS (p=0.001), even during AED withdrawal (p=0.002). There was no association between DP and prognosis regarding seizure control as the result of the surgical resection, either in patients with shorter or in those with longer period of follow-up. Our data support the hypothesis that DP reflects a brain network activation that helps avoid GTCS, even during AED withdrawal. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Hippocampal CA3 transcriptome signature correlates with initial precipitating injury in refractory mesial temporal lobe epilepsy.

    Directory of Open Access Journals (Sweden)

    Silvia Y Bando

    Full Text Available BACKGROUND: Prolonged febrile seizures constitute an initial precipitating injury (IPI commonly associated with refractory mesial temporal lobe epilepsy (RMTLE. In order to investigate IPI influence on the transcriptional phenotype underlying RMTLE we comparatively analyzed the transcriptomic signatures of CA3 explants surgically obtained from RMTLE patients with (FS or without (NFS febrile seizure history. Texture analyses on MRI images of dentate gyrus were conducted in a subset of surgically removed sclerotic hippocampi for identifying IPI-associated histo-radiological alterations. METHODOLOGY/PRINCIPAL FINDINGS: DNA microarray analysis revealed that CA3 global gene expression differed significantly between FS and NFS subgroups. An integrative functional genomics methodology was used for characterizing the relations between GO biological processes themes and constructing transcriptional interaction networks defining the FS and NFS transcriptomic signatures and its major gene-gene links (hubs. Co-expression network analysis showed that: i CA3 transcriptomic profiles differ according to the IPI; ii FS distinctive hubs are mostly linked to glutamatergic signalization while NFS hubs predominantly involve GABAergic pathways and neurotransmission modulation. Both networks have relevant hubs related to nervous system development, what is consistent with cell genesis activity in the hippocampus of RMTLE patients. Moreover, two candidate genes for therapeutic targeting came out from this analysis: SSTR1, a relevant common hub in febrile and afebrile transcriptomes, and CHRM3, due to its putative role in epilepsy susceptibility development. MRI texture analysis allowed an overall accuracy of 90% for pixels correctly classified as belonging to FS or NFS groups. Histological examination revealed that granule cell loss was significantly higher in FS hippocampi. CONCLUSIONS/SIGNIFICANCE: CA3 transcriptional signatures and dentate gyrus morphology fairly

  20. Widespread extrahippocampal NAA/(Cr+Cho) abnormalities in TLE with and without mesial temporal sclerosis.

    Science.gov (United States)

    Mueller, Susanne G; Ebel, Andreas; Barakos, Jerome; Scanlon, Cathy; Cheong, Ian; Finlay, Daniel; Garcia, Paul; Weiner, Michael W; Laxer, Kenneth D

    2011-04-01

    MR spectroscopy has demonstrated extrahippocampal NAA/(Cr+Cho) reductions in medial temporal lobe epilepsy with (TLE-MTS) and without (TLE-no) mesial temporal sclerosis. Because of the limited brain coverage of those previous studies, it was, however, not possible to assess differences in the distribution and extent of these abnormalities between TLE-MTS and TLE-no. This study used a 3D whole brain echoplanar spectroscopic imaging (EPSI) sequence to address the following questions: (1) Do TLE-MTS and TLE-no differ regarding severity and distribution of extrahippocampal NAA/(Cr+Cho) reductions? (2) Do extrahippocampal NAA/(Cr+Cho) reductions provide additional information for focus lateralization? Forty-three subjects (12 TLE-MTS, 13 TLE-no, 18 controls) were studied with 3D EPSI. Statistical parametric mapping (SPM2) was used to identify regions of significantly decreased NAA/(Cr+Cho) in TLE groups and in individual patients. TLE-MTS and TLE-no had widespread extrahippocampal NAA/(Cr+Cho) reductions. NAA/(Cr+Cho) reductions had a bilateral fronto-temporal distribution in TLE-MTS and a more diffuse, less well defined distribution in TLE-no. Extrahippocampal NAA/(Cr+Cho) decreases in the single subject analysis showed a large inter-individual variability and did not provide additional focus lateralizing information. Extrahippocampal NAA/(Cr+Cho) reductions in TLE-MTS and TLE-no are neither focal nor homogeneous. This reduces their value for focus lateralization and suggests a heterogeneous etiology of extrahippocampal spectroscopic metabolic abnormalities in TLE.

  1. Multivariate pattern analysis reveals anatomical connectivity differences between the left and right mesial temporal lobe epilepsy

    Directory of Open Access Journals (Sweden)

    Peng Fang

    2015-01-01

    Full Text Available Previous studies have demonstrated differences of clinical signs and functional brain network organizations between the left and right mesial temporal lobe epilepsy (mTLE, but the anatomical connectivity differences underlying functional variance between the left and right mTLE remain uncharacterized. We examined 43 (22 left, 21 right mTLE patients with hippocampal sclerosis and 39 healthy controls using diffusion tensor imaging. After the whole-brain anatomical networks were constructed for each subject, multivariate pattern analysis was applied to classify the left mTLE from the right mTLE and extract the anatomical connectivity differences between the left and right mTLE patients. The classification results reveal 93.0% accuracy for the left mTLE versus the right mTLE, 93.4% accuracy for the left mTLE versus controls and 90.0% accuracy for the right mTLE versus controls. Compared with the right mTLE, the left mTLE exhibited a different connectivity pattern in the cortical-limbic network and cerebellum. The majority of the most discriminating anatomical connections were located within or across the cortical-limbic network and cerebellum, thereby indicating that these disease-related anatomical network alterations may give rise to a portion of the complex of emotional and memory deficit between the left and right mTLE. Moreover, the orbitofrontal gyrus, cingulate cortex, hippocampus and parahippocampal gyrus, which exhibit high discriminative power in classification, may play critical roles in the pathophysiology of mTLE. The current study demonstrated that anatomical connectivity differences between the left mTLE and the right mTLE may have the potential to serve as a neuroimaging biomarker to guide personalized diagnosis of the left and right mTLE.

  2. Low and High Frequency Hippocampal Stimulation for Drug-Resistant Mesial Temporal Lobe Epilepsy.

    Science.gov (United States)

    Lim, Siew-Na; Lee, Ching-Yi; Lee, Shih-Tseng; Tu, Po-Hsun; Chang, Bao-Luen; Lee, Chih-Hong; Cheng, Mei-Yun; Chang, Chun-Wei; Tseng, Wei-En Johnny; Hsieh, Hsiang-Yao; Chiang, Hsing-I; Wu, Tony

    2016-06-01

    Electrical stimulation of the hippocampus offers the possibility to treat patients with mesial temporal lobe epilepsy (MTLE) who are not surgical candidates. We report long-term follow-up results in five patients receiving low or high frequency hippocampal stimulation for drug-resistant MTLE. The patients underwent stereotactic implantation of quadripolar stimulating electrodes in the hippocampus. Two of the patients received unilateral electrode implantation, while the other three received bilateral implantation. Stimulation of the hippocampal electrodes was turned ON immediately after the implantation of an implantable pulse generator, with initial stimulation parameters: 1 V, 90-150 μs, 5 or 145 Hz. The frequency of seizures was monitored and compared with preimplantation baseline data. Two men and three women, aged 27-61 years were studied, with a mean follow-up period of 38.4 months (range, 30-42 months). The baseline seizure frequency was 2.0-15.3/month. The five patients had an average 45% (range 22-72%) reduction in the frequency of seizures after hippocampal stimulation over the study period. Low frequency hippocampal stimulation decreased the frequency of seizures in two patients (by 54% and 72%, respectively). No implantation- or stimulation-related side effects were reported. Electrical stimulation of the hippocampus is a minimally invasive and reversible method that can improve seizure outcomes in patients with drug-resistant MTLE. The optimal frequency of stimulation varied from patient to patient and therefore required individual setting. These experimental results warrant further controlled studies with a large patient population to evaluate the long-term effect of hippocampal stimulation with different stimulation parameters. © 2016 The Authors. Neuromodulation: Technology at the Neural Interface published by Wiley Periodicals, Inc. on behalf of International Neuromodulation Society.

  3. Familial mesial temporal lobe epilepsy and the borderland of déjà vu.

    Science.gov (United States)

    Perucca, Piero; Crompton, Douglas E; Bellows, Susannah T; McIntosh, Anne M; Kalincik, Tomas; Newton, Mark R; Vajda, Frank J E; Scheffer, Ingrid E; Kwan, Patrick; O'Brien, Terence J; Tan, K Meng; Berkovic, Samuel F

    2017-08-01

    The cause of mesial temporal lobe epilepsy (MTLE) is often unknown. We ascertained to what extent newly diagnosed nonlesional MTLE actually represents familial MTLE (FMTLE). We identified all consecutive patients presenting to the Austin Health First Seizure Clinic with MTLE and normal magnetic resonance imaging (MRI) or MRI evidence of hippocampal sclerosis over a 10-year period. Patients' first-degree relatives and pairwise age- and sex-matched controls underwent a comprehensive epilepsy interview. Each interview transcript was reviewed independently by 2 epileptologists, blinded to relative or control status. Reviewers classified each subject as follows: epilepsy, specifying if MTLE; manifestations suspicious for epilepsy; or unaffected. Physiological déjà vu was noted. Forty-four patients were included. At the Clinic, MTLE had been recognized to be familial in 2 patients only. Among 242 subjects interviewed, MTLE was diagnosed in 9 of 121 relatives versus 0 of 121 controls (p = 0.008). All affected relatives had seizures with intense déjà vu and accompanying features; 6 relatives had not been previously diagnosed. Déjà vu experiences that were suspicious, but not diagnostic, of MTLE occurred in 6 additional relatives versus none of the controls (p = 0.04). Physiological déjà vu was common, and did not differ significantly between relatives and controls. After completing the relatives' interviews, FMTLE was diagnosed in 8 of 44 patients (18.2%). FMTLE accounts for almost one-fifth of newly diagnosed nonlesional MTLE, and it is largely unrecognized without direct questioning of relatives. Relatives of patients with MTLE may experience déjà vu phenomena that clinically lie in the "borderland" between epileptic seizures and physiological déjà vu. Ann Neurol 2017;82:166-176. © 2017 American Neurological Association.

  4. Serious adverse effects of gamma knife radiosurgery for mesial temporal lobe epilepsy

    International Nuclear Information System (INIS)

    Kawamura, Tetsuro; Onishi, Hiroaki; Kohda, Yukihiko; Hirose, Genjiro

    2012-01-01

    Gamma knife radiosurgery (GKRS) for mesial temporal lobe epilepsy (MTLE) has been proposed as an alternative to surgical resection. We report serious adverse effects of the treatment after follow-up periods over 9 years in 11 patients treated with GKRS between 1997 and 2000. The target volume of the entorhinoamygdalohippocampectomy area was 4.8-17.1 ml. Marginal dose of 20-25 Gy to the 50% isodose was delivered. One patient was drowned after suffering seizure 7 months after GKRS. Two patients did not show any reduction in seizure frequency over 9 and 18 months. Both patients requested open surgery and became seizure-free postoperatively. Four of the other eight patients were classified as Engel's class I within 4 years after GKRS. One of the four patients experienced symptomatic radiation-induced cerebral edema transiently, one developed radiation necrosis and required surgery 5 years after GKRS, and one developed cognitive impairment with hemiparesis 10 years after GKRS. Magnetic resonance (MR) imaging showed a large cyst in the irradiated temporal lobe. This patient recovered fully after the cyst excision. Only one patient became seizure-free and antiepileptic drug-free without symptomatic radiation-induced complications. However, MR imaging revealed abnormal enhancement, cyst formation, and diffuse white matter change in the irradiated temporal lobe 9 years after GKRS. GKRS for MTLE causes adverse effects of delayed seizure remission and symptomatic radiation-induced complications. Therefore, GKRS cannot be considered as an ideal alternative to surgery for MTLE. Long-term follow-up studies including MR imaging with contrast medium are required for the patients even after successful control of seizures. (author)

  5. [A surgical case of mesial temporal lobe epilepsy associated with hippocampal sclerosis and traumatic neocortical lesion].

    Science.gov (United States)

    Kitazawa, Yu; Jin, Kazutaka; Iwasaki, Masaki; Suzuki, Hiroyoshi; Tanaka, Fumiaki; Nakasato, Nobukazu

    2017-11-25

    A 26-year-old right-handed woman, with a history of left temporal lobe contusion caused by a fall at the age of 9 months, started to have complex partial seizures with oral automatism at the age of 7 years. The seizures occurred once or twice a month despite combination therapy with several antiepileptic agents. Her history and imaging studies suggested the diagnosis of epilepsy arising from traumatic neocortical temporal lesion. Comprehensive assessment including long-term video EEG monitoring, MRI, FDG-PET, MEG, and neuropsychological evaluation was performed at the age of 26 years. The diagnosis was left mesial temporal lobe epilepsy associated with hippocampal atrophy and traumatic temporal cortical lesion. The patient was readmitted for surgical treatment at the age of 27 years. Intracranial EEG monitoring showed that ictal discharges started in the left hippocampus and spread to the traumatic lesion in the left posterior superior temporal gyrus 10 seconds after the onset. This case could not be classified as dual pathology exactly, because the traumatic left temporal cortical lesion did not show independent epileptogenicity. However, the traumatic lesion was highly likely to be the source of the epileptogenicity, and she had right hemispheric dominance for language and functional deterioration in the whole temporal cortex. Therefore, left amygdalo-hippocampectomy and left temporal lobectomy including the traumatic lesion were performed according to the diagnosis of dual pathology. Subsequently, she remained seizure-free for 3 years. Comprehensive assessment of seizure semiology, neurophysiology, neuroradiology, and neuropsychology is important to determine the optimum therapeutic strategies for drug-resistant epilepsy.

  6. Clinico-pathological factors influencing surgical outcome in drug resistant epilepsy secondary to mesial temporal sclerosis.

    Science.gov (United States)

    Savitr Sastri, B V; Arivazhagan, A; Sinha, Sanjib; Mahadevan, Anita; Bharath, R D; Saini, J; Jamuna, R; Kumar, J Keshav; Rao, S L; Chandramouli, B A; Shankar, S K; Satishchandra, P

    2014-05-15

    Mesial temporal sclerosis (MTS) is the most common cause of drug resistant epilepsy amenable for surgical treatment and seizure control. This study analyzed the outcome of patients with MTS following anterior temporal lobectomy and amygdalohippocampectomy (ATL-AH) over 10 years and correlated the electrophysiological and radiological factors with the post operative seizure outcome. Eighty seven patients were included in the study. Sixty seven (77.2%) patients had an Engel Class 1 outcome, 9 (11.4%) had Class 2 outcome. Engel's class 1 outcome was achieved in 89.9% at 1 year, while it reduced slightly to 81.9% at 2 years and 76.2% at 5 year follow up. Seventy seven (88.5%) patients had evidence of hippocampal sclerosis on histopathology. Dual pathology was observed in 19 of 77 specimens with hippocampal sclerosis, but did not influence the outcome. Factors associated with an unfavorable outcome included male gender (p=0.04), and a higher frequency of pre-operative seizures (p=0.005), whereas the presence of febrile seizures (p=0.048) and loss of hippocampal neurons in CA4 region on histopathology (p=0.040) were associated with favorable outcome. The effect of CA4 loss on outcome is probably influenced by neuronal loss in other subfields as well since isolated CA4 loss was rare. Abnormal post operative EEG at the end of 1 week was found to be a significant factor predicting unfavorable outcome (p=0.005). On multivariate analysis, the pre-operative seizure frequency was the only significant factor affecting outcome. The present study observed excellent seizure free outcome in a carefully selected cohort of patients with MTS with refractory epilepsy. The presence of dual pathology did not influence the outcome. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Multivariate pattern analysis reveals anatomical connectivity differences between the left and right mesial temporal lobe epilepsy.

    Science.gov (United States)

    Fang, Peng; An, Jie; Zeng, Ling-Li; Shen, Hui; Chen, Fanglin; Wang, Wensheng; Qiu, Shijun; Hu, Dewen

    2015-01-01

    Previous studies have demonstrated differences of clinical signs and functional brain network organizations between the left and right mesial temporal lobe epilepsy (mTLE), but the anatomical connectivity differences underlying functional variance between the left and right mTLE remain uncharacterized. We examined 43 (22 left, 21 right) mTLE patients with hippocampal sclerosis and 39 healthy controls using diffusion tensor imaging. After the whole-brain anatomical networks were constructed for each subject, multivariate pattern analysis was applied to classify the left mTLE from the right mTLE and extract the anatomical connectivity differences between the left and right mTLE patients. The classification results reveal 93.0% accuracy for the left mTLE versus the right mTLE, 93.4% accuracy for the left mTLE versus controls and 90.0% accuracy for the right mTLE versus controls. Compared with the right mTLE, the left mTLE exhibited a different connectivity pattern in the cortical-limbic network and cerebellum. The majority of the most discriminating anatomical connections were located within or across the cortical-limbic network and cerebellum, thereby indicating that these disease-related anatomical network alterations may give rise to a portion of the complex of emotional and memory deficit between the left and right mTLE. Moreover, the orbitofrontal gyrus, cingulate cortex, hippocampus and parahippocampal gyrus, which exhibit high discriminative power in classification, may play critical roles in the pathophysiology of mTLE. The current study demonstrated that anatomical connectivity differences between the left mTLE and the right mTLE may have the potential to serve as a neuroimaging biomarker to guide personalized diagnosis of the left and right mTLE.

  8. Large-scale brain networks are distinctly affected in right and left mesial temporal lobe epilepsy.

    Science.gov (United States)

    de Campos, Brunno Machado; Coan, Ana Carolina; Lin Yasuda, Clarissa; Casseb, Raphael Fernandes; Cendes, Fernando

    2016-09-01

    Mesial temporal lobe epilepsy (MTLE) with hippocampus sclerosis (HS) is associated with functional and structural alterations extending beyond the temporal regions and abnormal pattern of brain resting state networks (RSNs) connectivity. We hypothesized that the interaction of large-scale RSNs is differently affected in patients with right- and left-MTLE with HS compared to controls. We aimed to determine and characterize these alterations through the analysis of 12 RSNs, functionally parceled in 70 regions of interest (ROIs), from resting-state functional-MRIs of 99 subjects (52 controls, 26 right- and 21 left-MTLE patients with HS). Image preprocessing and statistical analysis were performed using UF(2) C-toolbox, which provided ROI-wise results for intranetwork and internetwork connectivity. Intranetwork abnormalities were observed in the dorsal default mode network (DMN) in both groups of patients and in the posterior salience network in right-MTLE. Both groups showed abnormal correlation between the dorsal-DMN and the posterior salience, as well as between the dorsal-DMN and the executive-control network. Patients with left-MTLE also showed reduced correlation between the dorsal-DMN and visuospatial network and increased correlation between bilateral thalamus and the posterior salience network. The ipsilateral hippocampus stood out as a central area of abnormalities. Alterations on left-MTLE expressed a low cluster coefficient, whereas the altered connections on right-MTLE showed low cluster coefficient in the DMN but high in the posterior salience regions. Both right- and left-MTLE patients with HS have widespread abnormal interactions of large-scale brain networks; however, all parameters evaluated indicate that left-MTLE has a more intricate bihemispheric dysfunction compared to right-MTLE. Hum Brain Mapp 37:3137-3152, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. © 2016 The Authors Human Brain Mapping Published by

  9. Immunogenetic predisposing factors for mesial temporal lobe epilepsy with hippocampal sclerosis.

    Science.gov (United States)

    Leal, Bárbara; Chaves, João; Carvalho, Cláudia; Bettencourt, Andreia; Brito, Cláudia; Boleixa, Daniela; Freitas, Joel; Brás, Sandra; Lopes, João; Ramalheira, João; Costa, Paulo P; da Silva, Berta Martins; da Silva, António Martins

    2018-04-01

    Neuroinflammation appears as an important epileptogenic mechanism. Experimental and clinical studies have demonstrated an upregulation of pro-inflammatory cytokines such as IL-1β and TNF-α, in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). Expression of these cytokines can be modulated by polymorphisms such as rs16944 and rs1800629, respectively, both of which have been associated with febrile seizures (FS) and MTLE-HS development. The human leukocyte antigen (HLA) system has also been implicated in diverse epileptic entities, suggesting a variable role of this system in epilepsy. Our aim was to analyse the association between immunogenetic factors and MTLE-HS development. For that rs16944 (-511 T>C, IL-1β), rs1800629 (-308 G>A, TNF-α) polymorphisms and HLA-DRB1 locus were genotyped in a Portuguese Population. We studied 196 MTLE-HS patients (108 females, 88 males, 44.7 ± 12.0 years, age of onset = 13.6 ± 10.3 years, 104 with FS antecedents) and 282 healthy controls in a case-control study. The frequency of rs16944 TT genotype was higher in MTLE-HS patients compared to controls (14.9% in MTLE-HS vs. 7.7% in controls, p = 0.021, OR [95% CI] = 2.20 [1.13-4.30]). This association was independent of FS antecedents. No association was observed between rs1800629 genotypes or HLA-DRB1 alleles and MTLE-HS susceptibility. Also, no correlation was observed between the studied polymorphisms and disease age of onset. The rs16944 TT genotype is associated with MTLE-HS development what may be explained by the higher IL-1β levels produced by this genotype. High IL-1β levels may have neurotoxic effects or imbalance neurotransmission leading to seizures.

  10. Comparative effectiveness of antiepileptic drugs in patients with mesial temporal lobe epilepsy with hippocampal sclerosis.

    Science.gov (United States)

    Androsova, Ganna; Krause, Roland; Borghei, Mojgansadat; Wassenaar, Merel; Auce, Pauls; Avbersek, Andreja; Becker, Felicitas; Berghuis, Bianca; Campbell, Ellen; Coppola, Antonietta; Francis, Ben; Wolking, Stefan; Cavalleri, Gianpiero L; Craig, John; Delanty, Norman; Koeleman, Bobby P C; Kunz, Wolfram S; Lerche, Holger; Marson, Anthony G; Sander, Josemir W; Sills, Graeme J; Striano, Pasquale; Zara, Federico; Sisodiya, Sanjay M; Depondt, Chantal

    2017-10-01

    Mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) is a common epilepsy syndrome that is often poorly controlled by antiepileptic drug (AED) treatment. Comparative AED effectiveness studies in this condition are lacking. We report retention, efficacy, and tolerability in a cohort of patients with MTLE-HS. Clinical data were collected from a European database of patients with epilepsy. We estimated retention, 12-month seizure freedom, and adverse drug reaction (ADR) rates for the 10 most commonly used AEDs in patients with MTLE-HS. Seven hundred sixty-seven patients with a total of 3,249 AED trials were included. The highest 12-month retention rates were observed with carbamazepine (85.9%), valproate (85%), and clobazam (79%). Twelve-month seizure freedom rates varied from 1.2% for gabapentin and vigabatrin to 11% for carbamazepine. Response rates were highest for AEDs that were prescribed as initial treatment and lowest for AEDs that were used in a third or higher instance. ADRs were reported in 47.6% of patients, with the highest rates observed with oxcarbazepine (35.7%), topiramate (30.9%), and pregabalin (27.4%), and the lowest rates with clobazam (6.5%), gabapentin (8.9%), and lamotrigine (16.6%). The most commonly reported ADRs were lethargy and drowsiness, dizziness, vertigo and ataxia, and blurred vision and diplopia. Our results did not demonstrate any clear advantage of newer versus older AEDs. Our results provide useful insights into AED retention, efficacy, and ADR rates in patients with MTLE-HS. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

  11. Abnormalities of hippocampal signal intensity in patients with familial mesial temporal lobe epilepsy

    Directory of Open Access Journals (Sweden)

    Coan A.C.

    2004-01-01

    Full Text Available Mesial temporal lobe epilepsy (MTLE is associated with hippocampal atrophy and hippocampal signal abnormalities. In our series of familial MTLE (FMTLE, we found a high proportion of hippocampal abnormalities. To quantify signal abnormalities in patients with FMTLE we studied 152 individuals (46 of them asymptomatic with FMTLE. We used NIH-Image® for volumetry and signal quantification in coronal T1 inversion recovery and T2 for all cross-sections of the hippocampus. Values diverging by 2 or more SD from the control mean were considered abnormal. T2 hippocampal signal abnormalities were found in 52% of all individuals: 54% of affected subjects and 48% of asymptomatic subjects. T1 hippocampal signal changes were found in 34% of all individuals: 42.5% of affected subjects and 15% of asymptomatic subjects. Analysis of the hippocampal head (first three slices revealed T2 abnormalities in 73% of all individuals (74% of affected subjects and 72% of asymptomatic subjects and T1 abnormalities in 59% (67% of affected subjects and 41% of asymptomatic subjects. Affected individuals had smaller volumes than controls (P < 0.0001. There was no difference in hippocampal volumes between asymptomatic subjects and controls, although 39% of asymptomatic patients had hippocampal atrophy. Patients with an abnormal hippocampal signal (133 individuals had smaller ipsilateral volume, but no linear correlation could be determined. Hippocampal signal abnormalities in FMTLE were more frequently found in the hippocampal head in both affected and asymptomatic family members, including those with normal volumes. These results indicate that subtle abnormalities leading to an abnormal hippocampal signal in FMTLE are not necessarily related to seizures and may be determined by genetic factors.

  12. Imaging of odor perception delineates functional disintegration of the limbic circuits in mesial temporal lobe epilepsy.

    Science.gov (United States)

    Ciumas, Carolina; Lindström, Per; Aoun, Bernard; Savic, Ivanka

    2008-01-15

    Metabolic and neuro-receptor abnormalities within the extrafocal limbic circuits are established in mesial temporal lobe epilepsy (MTLE). However, very little is known about how these circuits process external stimuli. We tested whether odor activation can help delineate limbic functional disintegration in MTLE, and measured cerebral blood flow with PET during birhinal smelling of familiar and unfamiliar odors, using smelling of odorless air as the baseline condition. Patients with MTLE (13 left-sided, 10 right-sided) and 21 controls were investigated. In addition to odor activation, the analysis included functional connectivity, using right and left piriform cortex as seed regions. Healthy controls activated the amygdala, piriform, anterior insular, and cingulate cortices on both sides. Smelling of familiar odors engaged, in addition, the right parahippocampus, and the left Brodmann Area (BA) 44, 45, 47. Patients failed to activate the amygdala, piriform and the anterior insular cortex in the epileptogenic hemisphere. Furthermore, those with left MTLE did not activate the left BA 44, 45 and 47 with familiar odors, which they perceived as less familiar than controls. Congruent with the activation data each seed region was in patients functionally disconnected with the contralateral amygdala+piriform+insular cortex. The functional disintegration in patients exceeded the reduced activation, and included the contralateral temporal neocortex, and in subjects with right MTLE also the right orbitofrontal cortex. Imaging of odor perception may be used to delineate functional disintegration of the limbic networks in MTLE. It shows an altered response in several regions, which may underlie some interictal behavioral problems associated with this condition.

  13. Relationship between refractive index and mineral content of enamel and dentin using SS-OCT and TMR

    Science.gov (United States)

    Hariri, Ilnaz; Sadr, Alireza; Shimada, Yasushi; Nakashima, Syozi; Sumi, Yasunori; Tagami, Junji

    2012-01-01

    The aim of this work was to investigate relationship between refractive index (n) and mineral content (MC) (vol %) of enamel and dentin using swept-source optical coherence tomography (SS-OCT) and transverse microradiography (TMR). Enamel and dentin blocks were partitioned into three regions. The middle partition of each sample was covered with a nail polish to protect the sound area during exposure to the treatment solutions. Samples were demineralized in a demineralizing solution, which was refreshed once a week, for 2 months. One window was covered with acid-resistant varnish, leaving the other window exposed; the samples were placed in a solution for remineralization. Samples then were sliced into disks with thickness of 300 μm to 400 μm and placed on metal plate in order to capture cross-sectional images of sound, demineralized and remineralized regions by OCT at 1319 nm center wavelength. The n then was calculated via formula using image analysis software. Following n measurement, these specimens were further polished for the TMR analysis. Correlation between OCT n and TMR MC was examined. A significant and highly positive correlation was found between the measured n and the actual MC at the corresponding locations (Pearson correlation coefficients (r) were 0.94 and 0.97 in enamel and 0.95 and 0.91 in dentin after de-/remineralization process, respectively p < 0.05). OCT showed a potential for quantitative analysis of the mineral loss or gain by measuring of the n in vitro. Supported by the grant from the Japanese Ministry of Education, Global Center of Excellence (GCOE) Program, "International Research Center for Molecular Science in Tooth and Bone Diseases."

  14. Microabrasion as treatment of enamel fluorosis

    Directory of Open Access Journals (Sweden)

    Ana Caroline Brito

    2008-01-01

    Full Text Available There is currently a trend in favor of using fluoride as a coadjuvant in reducing caries indexes, as much in underdeveloped as in developedcountries. However, simultaneously the indexes of dental fluorosis seem to grow in an inverse proportion. This is brought about by chronic ingestion of fluoride for a prolonged length of time or in high concentration. Enamel microabrasion is an effective method to remove superficial stains caused by this condition, which affects esthetics of that tissue. The use of 18% hydrochloric acid in association with pumice, despite being a simple and low cost method, has been gradually replaced due to its potential of causing damage to periodontal tissues. Thus, this article reports the treatment of a fluorosis clinical case solved with microabrasion using phosphoric acid 37%, because its costbenefit is supposedly better than with chloridric acid. The deliberate ingestion of toothpaste was the probable cause of the tooth stains. Due to the location of the teeth and to the patient’s smile, only the six upper anterior teeth were selected to receive the proposed treatment. Four clinical sessions, with a seven days interval between each other, were carried out using 37% phosphoric acid and pumice. Under rubber dam isolation, the two first sessions consisted of rubbing the acid-pumice mix on enamel surface using a rubber cup on slow speed, and abrasive paper strips on the interproximal tooth surfaces. On the two final sessions, only finishing touches were performed using a wooden spatula to manually rub the acid-pumice paste.

  15. Michael Jackson's Sound Stages

    OpenAIRE

    Morten Michelsen

    2012-01-01

    In order to discuss analytically spatial aspects of recorded sound William Moylan’s concept of ‘sound stage’ is developed within a musicological framework as part of a sound paradigm which includes timbre, texture and sound stage. Two Michael Jackson songs (‘The Lady in My Life’ from 1982 and ‘Scream’ from 1995) are used to: a) demonstrate the value of such a conceptualisation, and b) demonstrate that the model has its limits, as record producers in the 1990s began ignoring the conventions of...

  16. What is Sound?

    OpenAIRE

    Nelson, Peter

    2014-01-01

    What is sound? This question is posed in contradiction to the every-day understanding that sound is a phenomenon apart from us, to be heard, made, shaped and organised. Thinking through the history of computer music, and considering the current configuration of digital communi-cations, sound is reconfigured as a type of network. This network is envisaged as non-hierarchical, in keeping with currents of thought that refuse to prioritise the human in the world. The relationship of sound to musi...

  17. Light and Sound

    CERN Document Server

    Karam, P Andrew

    2010-01-01

    Our world is largely defined by what we see and hear-but our uses for light and sound go far beyond simply seeing a photo or hearing a song. A concentrated beam of light, lasers are powerful tools used in industry, research, and medicine, as well as in everyday electronics like DVD and CD players. Ultrasound, sound emitted at a high frequency, helps create images of a developing baby, cleans teeth, and much more. Light and Sound teaches how light and sound work, how they are used in our day-to-day lives, and how they can be used to learn about the universe at large.

  18. Influence of Surfactants and Fluoride against Enamel Erosion.

    Science.gov (United States)

    Zanatta, Rayssa Ferreira; Ávila, Daniele Mara da Silva; Miyamoto, Karen Mayumi; Torres, Carlos Rocha Gomes; Borges, Alessandra Bühler

    2018-06-06

    This study investigated the effect of surfactants associated with sodium fluoride (NaF) on enamel erosion prevention, using an erosion-remineralization in vitro model. Sodium lauryl sulfate (SLS), polysorbate 20 (P20), and cocoamidopropyl betaine (CAPB) were tested, at concentrations of 1.0 and 1.5%, and associated or not with NaF (275 ppm). The control groups were distilled water and the NaF solution. Bovine enamel samples (n = 12) were prepared and submitted to a 5-day cycling model: acid challenge (0.3% citric acid, pH 2.6, 4×/day), human saliva (2 h, 4×/day), and the treatment solutions (2 min, 2×/day). The protective potential of the agents against initial erosion was assessed by microhardness and the surface loss by profilometry. Enamel surface wettability was determined by goniometry, protein adsorption was measured by spectroscopy (FTIR), and the KOH-soluble fluoride was quantified. Goniometry showed that SLS and CAPB increased enamel wettability. No differences were found among the surfactants regarding protein adsorption. Microhardness showed that SLS reduced NaF protection. P20 (1 and 1.5%) and CAPB 1.5% presented a protective effect, but lower than the NaF solution. Profilometry showed that CAPB protected enamel, but no agent associated with NaF promoted a higher protection than the NaF solution alone. KOH-soluble fluoride analysis showed that all surfactants reduced the fluoride adsorption on the enamel surface. Therefore, the surfactants tested (except for P20) changed the enamel surface energy. The SLS decreased the protective potential of NaF on initial erosion, but no tested agent interfered with the protective effect of NaF on enamel erosive wear. © 2018 S. Karger AG, Basel.

  19. Enamel: From brittle to ductile like tribological response.

    Science.gov (United States)

    Guidoni, G; Swain, M; Jäger, I

    2008-10-01

    To identify the intrinsic nano-scale wear mechanisms of enamel by comparing it with that of highly brittle glass, and highly ductile copper and silver monocrystals. A sharp cube corner indenter tip (20-50 nm radius) was used to abrade glass, enamel as well as copper and silver monocrystals. Square abraded areas (5 microm x 5 microm, 10 microm x 10 microm) were generated with loads of 50 microN for enamel and 100 microN for the remaining materials (2D abrasion). The normal load and displacement data were utilized in a complementary manner to support the comparison. In addition normal and lateral forces were simultaneously measured along 10 microm single scratched lines (1D abrasion). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were also used to characterise the worn areas and debris. The sharp tip cuts into and ploughs the specimens creating a wedge or ridge of material ahead of itself which eventually detaches, for the ductile materials and at high loads in enamel. For glass and enamel at low loads, the indenter tip ploughs into the material and the removed material is redistributed and pressed back into the abraded area. The wear behaviour of enamel at the nano-level resembles that obtained with glass at low loads (50 microN) and that obtained with metal mono-crystals at high load (100 microN). The role of the microstructural heterogeneity in the wear behaviour of enamel is considered in the discussion. The relevance to clinical wear of enamel is also considered.

  20. DENTAL ENAMEL FORMATION AND IMPLICATIONS FOR ORAL HEALTH AND DISEASE.

    Science.gov (United States)

    Lacruz, Rodrigo S; Habelitz, Stefan; Wright, J Timothy; Paine, Michael L

    2017-07-01

    Dental enamel is the hardest and most mineralized tissue in extinct and extant vertebrate species and provides maximum durability that allows teeth to function as weapons and/or tools as well as for food processing. Enamel development and mineralization is an intricate process tightly regulated by cells of the enamel organ called ameloblasts. These heavily polarized cells form a monolayer around the developing enamel tissue and move as a single forming front in specified directions as they lay down a proteinaceous matrix that serves as a template for crystal growth. Ameloblasts maintain intercellular connections creating a semi-permeable barrier that at one end (basal/proximal) receives nutrients and ions from blood vessels, and at the opposite end (secretory/apical/distal) forms extracellular crystals within specified pH conditions. In this unique environment, ameloblasts orchestrate crystal growth via multiple cellular activities including modulating the transport of minerals and ions, pH regulation, proteolysis, and endocytosis. In many vertebrates, the bulk of the enamel tissue volume is first formed and subsequently mineralized by these same cells as they retransform their morphology and function. Cell death by apoptosis and regression are the fates of many ameloblasts following enamel maturation, and what cells remain of the enamel organ are shed during tooth eruption, or are incorporated into the tooth's epithelial attachment to the oral gingiva. In this review, we examine key aspects of dental enamel formation, from its developmental genesis to the ever-increasing wealth of data on the mechanisms mediating ionic transport, as well as the clinical outcomes resulting from abnormal ameloblast function. Copyright © 2017 the American Physiological Society.

  1. Indirect veneer treatment of anterior maxillary teeth with enamel hypoplasia

    OpenAIRE

    Juniarti, Devi Eka

    2010-01-01

    Background: Nowadays, aesthetic rehabilitation becomes a necessity. It is affected by patient’s background, especially career, social and economic status. The aesthetic abnormality of anterior teeth i.e discoloration, malposition and malformation can affect patient’s appearance, especially during smile. These dental abnormalities, as a result, can decrease patient’s performance. Dental malformation, for instance, can be caused by developmental tooth defect, such as enamel hypoplasia. Enamel h...

  2. Early Sound Symbolism for Vowel Sounds

    Directory of Open Access Journals (Sweden)

    Ferrinne Spector

    2013-06-01

    Full Text Available Children and adults consistently match some words (e.g., kiki to jagged shapes and other words (e.g., bouba to rounded shapes, providing evidence for non-arbitrary sound–shape mapping. In this study, we investigated the influence of vowels on sound–shape matching in toddlers, using four contrasting pairs of nonsense words differing in vowel sound (/i/ as in feet vs. /o/ as in boat and four rounded–jagged shape pairs. Crucially, we used reduplicated syllables (e.g., kiki vs. koko rather than confounding vowel sound with consonant context and syllable variability (e.g., kiki vs. bouba. Toddlers consistently matched words with /o/ to rounded shapes and words with /i/ to jagged shapes (p < 0.01. The results suggest that there may be naturally biased correspondences between vowel sound and shape.

  3. Refining enamel thickness measurements from B-mode ultrasound images.

    Science.gov (United States)

    Hua, Jeremy; Chen, Ssu-Kuang; Kim, Yongmin

    2009-01-01

    Dental erosion has been growing increasingly prevalent with the rise in consumption of heavy starches, sugars, coffee, and acidic beverages. In addition, various disorders, such as Gastroenterological Reflux Disease (GERD), have symptoms of rapid rates of tooth erosion. The measurement of enamel thickness would be important for dentists to assess the progression of enamel loss from all forms of erosion, attrition, and abrasion. Characterizing enamel loss is currently done with various subjective indexes that can be interpreted in different ways by different dentists. Ultrasound has been utilized since the 1960s to determine internal tooth structure, but with mixed results. Via image processing and enhancement, we were able to refine B-mode dental ultrasound images for more accurate enamel thickness measurements. The mean difference between the measured thickness of the occlusal enamel from ultrasound images and corresponding gold standard CT images improved from 0.55 mm to 0.32 mm with image processing (p = 0.033). The difference also improved from 0.62 to 0.53 mm at the buccal/lingual enamel surfaces, but not significantly (p = 0.38).

  4. Separate whitening effects on enamel and dentin after fourteen days.

    Science.gov (United States)

    Kugel, Gerard; Petkevis, Jason; Gurgan, Sevil; Doherty, Eileen

    2007-01-01

    The purpose of this study was to investigate the mechanism of action of a bleaching agent, as it relates to enamel and dentin. Twenty-six extracted human molar teeth were sectioned at the cemento-enamel junction and were randomly assigned to two groups. L*a*b* readings were taken with a spectrophotometer: on buccal surfaces of the crown, at enamel and dentin. The teeth were exposed to carbamide peroxide or placebo gel and L*a*b* scores were again recorded to determine color changes. Treatments were compared using ancova test with baseline color as the covariate. Relative to placebo, buccal surfaces exhibited the greatest Deltab* and DeltaL* color change. On buccal surfaces, the adjusted mean (SE) treatment differences were -7.8 (1.00) for Deltab* and 5.7 (0.97) for DeltaL, with groups differing significantly (p enamel surfaces, treatment differences were -3.6 (0.61) for Deltab* and 4.6 (0.80) for DeltaL* (p tooth crowns exposed to carbamide peroxide 15% was because of the color change in enamel. As compared to enamel, dentin was less affected after 14 days.

  5. Anisotropic properties of the enamel organic extracellular matrix.

    Science.gov (United States)

    do Espírito Santo, Alexandre R; Novaes, Pedro D; Line, Sérgio R P

    2006-05-01

    Enamel biosynthesis is initiated by the secretion, processing, and self-assembly of a complex mixture of proteins. This supramolecular ensemble controls the nucleation of the crystalline mineral phase. The detection of anisotropic properties by polarizing microscopy has been extensively used to detect macromolecular organizations in ordinary histological sections. The aim of this work was to study the birefringence of enamel organic matrix during the development of rat molar and incisor teeth. Incisor and molar teeth of rats were fixed in 2% paraformaldehyde/0.5% glutaraldehyde in 0.2 M phosphate-buffered saline (PBS), pH 7.2, and decalcified in 5% nitric acid/4% formaldehyde. After paraffin embedding, 5-microm-thick sections were obtained, treated with xylene, and hydrated. Form birefringence curves were obtained after measuring optical retardations in imbibing media, with different refractive indices. Our observations showed that enamel organic matrix of rat incisor and molar teeth is strongly birefringent, presenting an ordered supramolecular structure. The birefringence starts during the early secretion phase and disappears at the maturation phase. The analysis of enamel organic matrix birefringence may be used to detect the effects of genetic and environmental factors on the supramolecular orientation of enamel matrix and their effects on the structure of mature enamel.

  6. Theobromine Effects on Enamel Surface Microhardness: In Vitro

    Directory of Open Access Journals (Sweden)

    Grace Syafira

    2013-07-01

    Full Text Available Dental caries is still a dental health problem in Indonesia. Fluoride, one of the dental caries prevention material, but its safety and the danger of fluorosis is still debated. Theobromine is an alkaloid compound contained in cocoa beans. Theobromine is believed to increase enamel microhardness with mineral changes in the enamel superficial layer. Objectives: To determine the influence of theobromine on the enamel surface microhardness. Methods: This study used 40 premolar tooth crown pieces that were embedded in epoxy resin. Furthermore specimens were randomly divided into 4 groups, which were control (distilled water, theobromine 100 mg/L (T100, theobromine 500 mg/L (T500 and theobromine 1000 mg/L (T1000. Specimens were immersed for 15 minutes and microhardness test was performed using Knoop microhardness tester. Results: Increasing enamel microhardness was observed after treatment with four different theobromine concentrations. The highest icreased of enamel microhardness was shown in T1000 group and difference compared to other groups were statistically significant (p<0.05. Conclusion: theobromine is a potential dental caries prevention material due to its effect in improving the microhardness of tooth enamel.

  7. Ca2+ transport and signalling in enamel cells

    Science.gov (United States)

    Nurbaeva, Meerim K.; Eckstein, Miriam; Feske, Stefan

    2016-01-01

    Abstract Dental enamel is one of the most remarkable examples of matrix‐mediated biomineralization. Enamel crystals form de novo in a rich extracellular environment in a stage‐dependent manner producing complex microstructural patterns that are visually stunning. This process is orchestrated by specialized epithelial cells known as ameloblasts which themselves undergo striking morphological changes, switching function from a secretory role to a cell primarily engaged in ionic transport. Ameloblasts are supported by a host of cell types which combined represent the enamel organ. Fully mineralized enamel is the hardest tissue found in vertebrates owing its properties partly to the unique mixture of ionic species represented and their highly organized assembly in the crystal lattice. Among the main elements found in enamel, Ca2+ is the most abundant ion, yet how ameloblasts modulate Ca2+ dynamics remains poorly known. This review describes previously proposed models for passive and active Ca2+ transport, the intracellular Ca2+ buffering systems expressed in ameloblasts and provides an up‐dated view of current models concerning Ca2+ influx and extrusion mechanisms, where most of the recent advances have been made. We also advance a new model for Ca2+ transport by the enamel organ. PMID:27510811

  8. Enamel dose calculation by electron paramagnetic resonance spectral simulation technique

    International Nuclear Information System (INIS)

    Dong Guofu; Cong Jianbo; Guo Linchao; Ning Jing; Xian Hong; Wang Changzhen; Wu Ke

    2011-01-01

    Objective: To optimize the enamel electron paramagnetic resonance (EPR) spectral processing by using the EPR spectral simulation method to improve the accuracy of enamel EPR dosimetry and reduce artificial error. Methods: The multi-component superimposed EPR powder spectral simulation software was developed to simulate EPR spectrum models of the background signal (BS) and the radiation- induced signal (RS) of irradiated enamel respectively. RS was extracted from the multi-component superimposed spectrum of irradiated enamel and its amplitude was calculated. The dose-response curve was then established for calculating the doses of a group of enamel samples. The result of estimated dose was compared with that calculated by traditional method. Results: BS was simulated as a powder spectrum of gaussian line shape with the following spectrum parameters: g=2.00 35 and Hpp=0.65-1.1 mT, RS signal was also simulated as a powder spectrum but with axi-symmetric spectrum characteristics. The spectrum parameters of RS were: g ⊥ =2.0018, g ‖ =1.9965, Hpp=0.335-0.4 mT. The amplitude of RS had a linear response to radiation dose with the regression equation as y=240.74x + 76 724 (R 2 =0.9947). The expectation of relative error of dose estimation was 0.13. Conclusions: EPR simulation method has improved somehow the accuracy and reliability of enamel EPR dose estimation. (authors)

  9. Enamel lesions in development, classification in Costa Rican families

    International Nuclear Information System (INIS)

    Murillo Knudsen, Gina; Berrocal Salazar, Cristina

    2013-01-01

    Enamel lesions in development were identified and classified in patients of Llano Grande de Cartago, examined at the Facultad de Odontologia of the Universidad de Costa Rica. A guide is provided over the topic. 15 children and 2 Costa Rican adults were selected. Clinical examinations, radiographs and clinical photographs were used as data collection method. Dental defects of the enamel were classified according to the possible genetic causes and without genetic causes. Imperfect Amelogenesis (IA) was diagnosed in 10 of patients. Hypoplastic IA was determined in 3 siblings with autosomal recessive inheritance, for 16% of the total sample. Hypomineralized IA was identified in an adult and two of his sons, with autosomal dominant inheritance. The remaining 4 cases of IA have been sporadic. Lesions of dental fluorosis were determined in the Horowitz index in 4 individuals, from 2 unrelated families. Other defects unspecified of the enamel or hypoplasias were found in 3 individuals. Enamel lesions in development should be classified with precision, for the purpose to inform to patients affected about their condition, origin, prognosis and appropriate treatment. The basis are established to implement reliability in the construction of family genealogy, identification and classification of enamel lesions, as well as the probabilities of future generations to express the lesions in the enamel of temporary or permanent dentition [es

  10. Enamel and dentin bond strength following gaseous ozone application.

    Science.gov (United States)

    Cadenaro, Milena; Delise, Chiara; Antoniollo, Francesca; Navarra, Ottavia Chiara; Di Lenarda, Roberto; Breschi, Lorenzo

    2009-08-01

    To evaluate the effects of gaseous ozone application on enamel and dentin bond strength produced by two self-etching adhesive systems. The shear bond strength test was conducted to assess adhesion on enamel (protocol 1), while the microtensile bond strength test was performed on dentin (protocol 2). Protocol 1: 96 bovine incisors were randomly divided into 4 groups, and enamel surfaces were bonded in accordance with the following treatments: (1E) ozone + Clearfil Protect Bond; (2E) Clearfil Protect Bond (control); (3E) ozone + Xeno III; (4E) Xeno III (control). Ozone gas was applied for 80 s. Shear bond strength was measured with a universal testing machine. Protocol 2: 40 noncarious human molars were selected. Middle/deep dentin was exposed and bonded in accordance with the following treatments: (1D) ozone+Clearfil Protect Bond; (2D) Clearfil Protect Bond (control); (3D) ozone+Xeno III (4D) Xeno III (control). Four-mm-thick buildups were built on the adhesives, then specimens were sectioned in accordance with the nontrimming technique. Specimens were stressed until failure occurred, and failure modes were analyzed. Shear bond and microtensile bond strength data were analyzed using two-way ANOVA and Tukey's post-hoc test. No statistical differences were found between ozone treated specimens and controls, neither on enamel nor on dentin irrespective of the tested adhesive. Clearfil Protect Bond showed higher bond strength to enamel than Xeno III, irrespective of the ozone treatment (p enamel and dentin bond strength.

  11. Metabolism in tooth enamel and reliability of retrospective EPR dosimetry connected with Chernobyl accident

    International Nuclear Information System (INIS)

    Brik, A.; Radchuk, V.; Scherbina, O.; Matyash, M.; Gaver, O.

    1996-01-01

    It is shown that the results of retrospective EPR dosimetry by tooth enamel are essentially determined by the fact that tooth enamel is the mineral of biological origin. The structure of tooth enamel, properties of radiation defects and the role of metabolism in tooth enamel are discussed. It is shown that at deep metamorphic modifications tooth enamel don't save information about its radiation history. The reliability and accuracy of retrospective EPR dosimetry are discussed. Because after Chernobyl accident have passed 10 years the application of tooth enamel for reconstruction of doses which are connected with Chernobyl accident need care and additional investigations

  12. [Differential diagnosis of dental enamel focal demineralization and fluorosis by means of spectrophotometry].

    Science.gov (United States)

    Makarova, N E; Vinnichenko, Yu A

    2018-01-01

    The article presents the results of spectrophotometric tooth enamel scanning for differential diagnosis of focal enamel demineralization and fluorosis. Research was conducted in vivo on teeth affected by these diseases. VITA EasyShade spectrophotometer measurements were made on the affected area and on the visually healthy part of enamel. The lightness appeared as the only one differential significant optical characteristics of tooth enamel. Lightness metrics were higher in the case of initial caries than on the healthy part of enamel when these metrics were lower in the case of fluorosis than on the healthy part of enamel.

  13. Indirect veneer treatment of anterior maxillary teeth with enamel hypoplasia

    Directory of Open Access Journals (Sweden)

    Devi Eka Juniarti

    2010-09-01

    Full Text Available Background: Nowadays, aesthetic rehabilitation becomes a necessity. It is affected by patient’s background, especially career, social and economic status. The aesthetic abnormality of anterior teeth i.e discoloration, malposition and malformation can affect patient’s appearance, especially during smile. These dental abnormalities, as a result, can decrease patient’s performance. Dental malformation, for instance, can be caused by developmental tooth defect, such as enamel hypoplasia. Enamel hypoplasia is a developmental defect caused by the lack of matrix amount which leads to thin and porous enamel. Enamel hypoplasia can also be caused by matrix calcification disturbance starting from the formation and development of enamel matrix causing defect and permanent changes which can occur on one or more tooth. Purpose: The aim of the study is to improve dental discoloration and tooth surface texture on anterior maxillary teeth with enamel hypoplasia by using indirect veneer with porcelain material. Case: A 20 years-old woman with enamel hypoplasia came to the Dental Hospital, Faculty of Dentistry Airlangga University. The patient wanted to improve her anterior maxillary teeth. It is clinically known that there were some opaque white spots (chalky spotted and porous on anterior teeth’s surface. Case management: Indirect veneer with porcelain material had been chosen as a restoration treatment which has excellent aesthetics and strength, and did not cause gingival irritation. As a result, the treatment could improve the confidence of the patient, and could also make their function normal. Conclusion: Indirect veneer is an effective treatment, which can improve patient’s appearance and self confidence.Latar belakang: Saat ini perbaikan estetik menjadi suatu kebutuhan. Kebutuhan akan estetik dipengaruhi latar belakang penderita, terutama karir, status sosial dan ekonomi. Hal ini disebabkan, kelainan estetik seperti diskolorasi, malposisi

  14. Correlation of neuropsychological and metabolic changes after epilepsy surgery in patients with left mesial temporal lobe epilepsy with hippocampal sclerosis.

    Science.gov (United States)

    Güvenç, Canan; Dupont, Patrick; Van den Stock, Jan; Seynaeve, Laura; Porke, Kathleen; Dries, Eva; Van Bouwel, Karen; van Loon, Johannes; Theys, Tom; Goffin, Karolien E; Van Paesschen, Wim

    2018-04-12

    Epilepsy surgery often causes changes in cognition and cerebral glucose metabolism. Our aim was to explore relationships between pre- and postoperative cerebral metabolism as measured with 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET) and neuropsychological test scores in patients with left mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS), who were rendered seizure-free after epilepsy surgery. Thirteen patients were included. All had neuropsychological testing and an interictal FDG-PET scan of the brain pre- and postoperative. Correlations between changes in neuropsychological test scores and metabolism were examined using statistical parametric mapping (SPM). There were no significant changes in the neuropsychological test scores pre- and postoperatively at the group level. Decreased metabolism was observed in the left mesial temporal regions and occipital lobe. Increased metabolism was observed in the bi-frontal and right parietal lobes, temporal lobes, occipital lobes, thalamus, cerebellum, and vermis. In these regions, we did not find a correlation between changes in metabolism and neuropsychological test scores. A significant negative correlation, however, was found between metabolic changes in the precuneus and Boston Naming Test (BNT) scores. There are significant metabolic decreases in the left mesial temporal regions and increases in the bi-frontal lobes; right parietal, temporal, and occipital lobes; right thalamus; cerebellum; and vermis in patients with left MTLE-HS who were rendered seizure-free after epilepsy surgery. We could not confirm that these changes translate into significant cognitive changes. A significant negative correlation was found between changes in confrontation naming and changes in metabolism in the precuneus. We speculate that the precuneus may play a compensatory role in patients with postoperative naming difficulties after left TLE surgery. Understanding of these neural mechanisms may aid in

  15. Right fronto-limbic atrophy is associated with reduced empathy in refractory unilateral mesial temporal lobe epilepsy.

    Science.gov (United States)

    Toller, Gianina; Adhimoolam, Babu; Rankin, Katherine P; Huppertz, Hans-Jürgen; Kurthen, Martin; Jokeit, Hennric

    2015-11-01

    Refractory mesial temporal lobe epilepsy (MTLE) is the most frequent focal epilepsy and is often accompanied by deficits in social cognition including emotion recognition, theory of mind, and empathy. Consistent with the neuronal networks that are crucial for normal social-cognitive processing, these impairments have been associated with functional changes in fronto-temporal regions. However, although atrophy in unilateral MTLE also affects regions of the temporal and frontal lobes that underlie social cognition, little is known about the structural correlates of social-cognitive deficits in refractory MTLE. In the present study, a psychometrically validated empathy questionnaire was combined with whole-brain voxel-based morphometry (VBM) to investigate the relationship between self-reported affective and cognitive empathy and gray matter volume in 55 subjects (13 patients with right MTLE, 9 patients with left MTLE, and 33 healthy controls). Consistent with the brain regions underlying social cognition, our results show that lower affective and cognitive empathy was associated with smaller volume in predominantly right fronto-limbic regions, including the right hippocampus, parahippocampal gyrus, thalamus, fusiform gyrus, inferior temporal gyrus, dorsomedial and dorsolateral prefrontal cortices, and in the bilateral midbrain. The only region that was associated with both affective and cognitive empathy was the right mesial temporal lobe. These findings indicate that patients with right MTLE are at increased risk for reduced empathy towards others' internal states and they shed new light on the structural correlates of impaired social cognition frequently accompanying refractory MTLE. In line with previous evidence from patients with neurodegenerative disease and stroke, the present study suggests that empathy depends upon the integrity of right fronto-limbic and brainstem regions and highlights the importance of the right mesial temporal lobe and midbrain

  16. InfoSound

    DEFF Research Database (Denmark)

    Sonnenwald, Diane H.; Gopinath, B.; Haberman, Gary O.

    1990-01-01

    The authors explore ways to enhance users' comprehension of complex applications using music and sound effects to present application-program events that are difficult to detect visually. A prototype system, Infosound, allows developers to create and store musical sequences and sound effects with...

  17. Breaking the Sound Barrier

    Science.gov (United States)

    Brown, Tom; Boehringer, Kim

    2007-01-01

    Students in a fourth-grade class participated in a series of dynamic sound learning centers followed by a dramatic capstone event--an exploration of the amazing Trashcan Whoosh Waves. It's a notoriously difficult subject to teach, but this hands-on, exploratory approach ignited student interest in sound, promoted language acquisition, and built…

  18. Sound propagation in cities

    NARCIS (Netherlands)

    Salomons, E.; Polinder, H.; Lohman, W.; Zhou, H.; Borst, H.

    2009-01-01

    A new engineering model for sound propagation in cities is presented. The model is based on numerical and experimental studies of sound propagation between street canyons. Multiple reflections in the source canyon and the receiver canyon are taken into account in an efficient way, while weak

  19. OMNIDIRECTIONAL SOUND SOURCE

    DEFF Research Database (Denmark)

    1996-01-01

    A sound source comprising a loudspeaker (6) and a hollow coupler (4) with an open inlet which communicates with and is closed by the loudspeaker (6) and an open outlet, said coupler (4) comprising rigid walls which cannot respond to the sound pressures produced by the loudspeaker (6). According...

  20. Hamiltonian Algorithm Sound Synthesis

    OpenAIRE

    大矢, 健一

    2013-01-01

    Hamiltonian Algorithm (HA) is an algorithm for searching solutions is optimization problems. This paper introduces a sound synthesis technique using Hamiltonian Algorithm and shows a simple example. "Hamiltonian Algorithm Sound Synthesis" uses phase transition effect in HA. Because of this transition effect, totally new waveforms are produced.

  1. Poetry Pages. Sound Effects.

    Science.gov (United States)

    Fina, Allan de

    1992-01-01

    Explains how elementary teachers can help students understand onomatopoeia, suggesting that they define onomatopoeia, share examples of it, read poems and have students discuss onomatopoeic words, act out common household sounds, write about sound effects, and create choral readings of onomatopoeic poems. Two appropriate poems are included. (SM)

  2. Exploring Noise: Sound Pollution.

    Science.gov (United States)

    Rillo, Thomas J.

    1979-01-01

    Part one of a three-part series about noise pollution and its effects on humans. This section presents the background information for teachers who are preparing a unit on sound. The next issues will offer learning activities for measuring the effects of sound and some references. (SA)

  3. Further morphological evidence on South African earliest Homo lower postcanine dentition: Enamel thickness and enamel dentine junction.

    Science.gov (United States)

    Pan, Lei; Dumoncel, Jean; de Beer, Frikkie; Hoffman, Jakobus; Thackeray, John Francis; Duployer, Benjamin; Tenailleau, Christophe; Braga, José

    2016-07-01

    The appearance of the earliest members of the genus Homo in South Africa represents a key event in human evolution. Although enamel thickness and enamel dentine junction (EDJ) morphology preserve important information about hominin systematics and dietary adaptation, these features have not been sufficiently studied with regard to early Homo. We used micro-CT to compare enamel thickness and EDJ morphology among the mandibular postcanine dentitions of South African early hominins (N = 30) and extant Homo sapiens (N = 26), with special reference to early members of the genus Homo. We found that South African early Homo shows a similar enamel thickness distribution pattern to modern humans, although three-dimensional average and relative enamel thicknesses do not distinguish australopiths, early Homo, and modern humans particularly well. Based on enamel thickness distributions, our study suggests that a dietary shift occurred between australopiths and the origin of the Homo lineage. We also observed that South African early Homo postcanine EDJ combined primitive traits seen in australopith molars with derived features observed in modern human premolars. Our results confirm that some dental morphological patterns in later Homo actually occurred early in the Homo lineage, and highlight the taxonomic value of premolar EDJ morphology in hominin species. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. [Two cases of mesial temporal lobe epilepsy associated with old intracerebral hemorrhage in the lateral temporal lobe without "dual pathology"].

    Science.gov (United States)

    Morioka, T; Nishio, S; Hisada, K; Muraishi, M; Ishibashi, H; Mamiya, K; Ohfu, M; Fukui, M

    1998-05-01

    Two cases of intractable temporal lobe epilepsy associated with old intracerebral hemorrhage in the lateral temporal lobe were reported. Although preoperative magnetic resonance imaging (MRI) failed to reveal hippocampal atrophy with T2 hyperintensity, electrocorticographic (ECoG) recording with chronic invasive subdural electrodes indicated the mesial temporal lobe to be an ictal onset zone. After anterior temporal lobectomy involving the lesion and hippocampectomy, the patients became seizure-free. Hippocampal sclerosis, namely "dual pathology", was not noted on histological examination. Careful ECoG recording with chronic subdural electrodes is mandatory even when the preoperative MRI does not demonstrate the radiological hippocampal sclerosis.

  5. Waveform analysis of sound

    CERN Document Server

    Tohyama, Mikio

    2015-01-01

    What is this sound? What does that sound indicate? These are two questions frequently heard in daily conversation. Sound results from the vibrations of elastic media and in daily life provides informative signals of events happening in the surrounding environment. In interpreting auditory sensations, the human ear seems particularly good at extracting the signal signatures from sound waves. Although exploring auditory processing schemes may be beyond our capabilities, source signature analysis is a very attractive area in which signal-processing schemes can be developed using mathematical expressions. This book is inspired by such processing schemes and is oriented to signature analysis of waveforms. Most of the examples in the book are taken from data of sound and vibrations; however, the methods and theories are mostly formulated using mathematical expressions rather than by acoustical interpretation. This book might therefore be attractive and informative for scientists, engineers, researchers, and graduat...

  6. Sound classification of dwellings

    DEFF Research Database (Denmark)

    Rasmussen, Birgit

    2012-01-01

    National schemes for sound classification of dwellings exist in more than ten countries in Europe, typically published as national standards. The schemes define quality classes reflecting different levels of acoustical comfort. Main criteria concern airborne and impact sound insulation between...... dwellings, facade sound insulation and installation noise. The schemes have been developed, implemented and revised gradually since the early 1990s. However, due to lack of coordination between countries, there are significant discrepancies, and new standards and revisions continue to increase the diversity...... is needed, and a European COST Action TU0901 "Integrating and Harmonizing Sound Insulation Aspects in Sustainable Urban Housing Constructions", has been established and runs 2009-2013, one of the main objectives being to prepare a proposal for a European sound classification scheme with a number of quality...

  7. Wear of human enamel: a quantitative in vitro assessment.

    Science.gov (United States)

    Kaidonis, J A; Richards, L C; Townsend, G C; Tansley, G D

    1998-12-01

    Many factors influence the extent and rate at which enamel wears. Clinical studies in humans are limited by difficulties in the accurate quantification of intra-oral wear and by a lack of control over the oral environment. The purpose of this study was to determine the wear characteristics of human dental enamel under controlled experimental conditions. An electro-mechanical tooth wear machine, in which opposing enamel surfaces of sectioned, extracted teeth were worn under various conditions, was used to simulate tooth grinding or bruxism. Enamel surface wear was quantified by weight to an accuracy of 0.1 mg, with water uptake and loss controlled. The variables considered included the structure and hardness of enamel, facet area, duration of tooth contact, relative speed of opposing surfaces, temperature, load, pH, and the nature of the lubricant. Enamel wear under non-lubricated conditions increased with increasing load over the range of 1.7 to 16.2 kg. The addition of a liquid lubricant (pH = 7) reduced enamel wear up to 6.7 kg, but when the load increased above this threshold, the rate of wear increased dramatically. With the viscosity of the lubricant constant and pH = 3, the rate of wear was further reduced to less than 10% of the non-lubricated rate at 9.95 kg, after which the rate again increased substantially. Under more extreme conditions (pH = 1.2, simulating gastric acids), the wear was excessive under all experimental loads. When saliva was used as a lubricant, the amount of wear was relatively low at 9.95 kg, but rapid wear occurred at 14.2 kg and above. These results indicate that under non-lubricated conditions, enamel wear remains low at high loads due to the dry-lubricating capabilities of fine enamel powder. Under lubricated conditions, low loads with an acidic lubricant lead to little enamel wear, whereas very low pH results in a high rate of wear under all loads.

  8. A quantitative light microscopic study of the odontoblast and subodontoblastic reactions to active and arrested enamel caries without cavitation

    DEFF Research Database (Denmark)

    Bjørndal, L.; Darvann, T.A.; Thylstrup, Anders

    1998-01-01

    Carious lesions, Computerized histomorphology, Dental pulp, Dentine, Enamel, Microradiography, Odontoblast......Carious lesions, Computerized histomorphology, Dental pulp, Dentine, Enamel, Microradiography, Odontoblast...

  9. The sound manifesto

    Science.gov (United States)

    O'Donnell, Michael J.; Bisnovatyi, Ilia

    2000-11-01

    Computing practice today depends on visual output to drive almost all user interaction. Other senses, such as audition, may be totally neglected, or used tangentially, or used in highly restricted specialized ways. We have excellent audio rendering through D-A conversion, but we lack rich general facilities for modeling and manipulating sound comparable in quality and flexibility to graphics. We need coordinated research in several disciplines to improve the use of sound as an interactive information channel. Incremental and separate improvements in synthesis, analysis, speech processing, audiology, acoustics, music, etc. will not alone produce the radical progress that we seek in sonic practice. We also need to create a new central topic of study in digital audio research. The new topic will assimilate the contributions of different disciplines on a common foundation. The key central concept that we lack is sound as a general-purpose information channel. We must investigate the structure of this information channel, which is driven by the cooperative development of auditory perception and physical sound production. Particular audible encodings, such as speech and music, illuminate sonic information by example, but they are no more sufficient for a characterization than typography is sufficient for characterization of visual information. To develop this new conceptual topic of sonic information structure, we need to integrate insights from a number of different disciplines that deal with sound. In particular, we need to coordinate central and foundational studies of the representational models of sound with specific applications that illuminate the good and bad qualities of these models. Each natural or artificial process that generates informative sound, and each perceptual mechanism that derives information from sound, will teach us something about the right structure to attribute to the sound itself. The new Sound topic will combine the work of computer

  10. Morphometric MRI features are associated with surgical outcome in mesial temporal lobe epilepsy with hippocampal sclerosis.

    Science.gov (United States)

    Garcia, Maria Teresa Fernandes Castilho; Gaça, Larissa Botelho; Sandim, Gabriel Barbosa; Assunção Leme, Idaiane Batista; Carrete, Henrique; Centeno, Ricardo Silva; Sato, João Ricardo; Yacubian, Elza Márcia Targas

    2017-05-01

    Corticoamygdalohippocampectomy (CAH) improves seizure control, quality of life, and decreases mortality for refractory mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). One-third of patients continue having seizures, and it is pivotal to determine structural abnormalities that might influence the postoperative outcome. Studies indicate that nonhippocampal regions may play a role in the epileptogenic network in MTLE-HS and could generate seizures postoperatively. The aim of this study is to analyze areas of atrophy, not always detected on routine MRI, comparing patients who became seizure free (SF) with those non seizure free (NSF) after CAH, in an attempt to establish possible predictors of surgical outcome. 105 patients with refractory MTLE-HS submitted to CAH (59 left MTLE; 46 males) and 47 controls were enrolled. FreeSurfer was performed for cortical thickness and volume estimation comparing patients to controls and SF versus NSF patients. The final sample after post processing procedures resulted in 99 patients. Cortical thickness analyses showed reductions in left insula in NSF patients compared to those SF. Significant volume reductions in SF patients were present in bilateral thalami, hippocampi and pars opercularis, left parahippocampal gyrus and right temporal pole. In NSF patients reductions were present bilaterally in thalami, hippocampi, entorhinal cortices, superior frontal and supramarginal gyri; on the left: superior and middle temporal gyri, temporal pole, parahippocampal gyrus, pars opercularis and middle frontal gyrus; and on the right: precentral, superior, middle and inferior temporal gyri. Comparison between SF and NSF patients showed ipsilateral gray matter reductions in the right entorhinal cortex (p=0.003) and contralateral parahippocampal gyrus (p=0.05) in right MTLE-HS. Patients NSF had a longer duration of epilepsy than those SF (p=0.028). NSF patients exhibited more extensive areas of atrophy than SF ones. As entorhinal

  11. Magnetic resonance in the diagnostic imaging study of mesial temporal sclerosis

    International Nuclear Information System (INIS)

    Pastor, E.; Sanchez, J. C.; Rodriguez, I.; Altuzarra, A.; Machado, F.; Aguilar, D.

    2001-01-01

    Mesial temporal sclerosis (MTS) consists of hippocampal atrophy and gliosis and is the most common cause of temporal lobe epilepsy. The objective of the authors was to establish a magnetic resonance imaging (MRI) protocol for its diagnosis. A prospective study was carried out in 72 patients with drug resistant complex partial seizures (42 women and 30 men ranging in age from 6 to 66 year: mean: 30 years). Using a 1.5-Tesla magnet, paracoronal sections were made in hippocampi for T1-weighted inversion-recovery images and volume measurements, fluid-attenuated inversion-recovery (FLAIR) and T2 relaxometry. A control group of 30 health volunteers was included in the study. MTS was considered to be indicated by the presence of atrophy and hyperintensity in hippocampi on T2-weighted images. There were no differences among the hippocampi of the healthy individuals. The confidence intervals (mean± 1.96 SD) were 4169 mm''3-5911 mm''3 for volume of right side, 4097 mm''3-5940 mm''3 for volume of left side and 98-113 ms for T2 relaxation time. MTS was detected in 40 patients (55.5%): 23 cases involving the left side, 13 involving the right and 4 cases of bilateral asymmetric involvement. The 95% confidence intervals for the diagnostic validity of the results (sensitivity/specificity) were (88.8%-97.2%)/(87.6%-96.4%) for T1 volumetry, (88.8%-97.2%)(95.7%-100.3%) for FLAIR and (85.4%-96.6%)/(85.4%-96.6%) for T2 relaxometry. In 5 cases of MTS, astrophy of other extra hippocampal structures was also observed, and MTS was associated with an extra hippocampal lesion (dual pathology), especially neurona migration disorders, in 8 patients. Seventeen patients (23.5%) presented lesions without MTS (tumors, cortical dysplasias and heterotopias) and there was no MRI evidence of anomalies in 15 (21%). Twenty-five patients underwent surgical treatment: 20 with MTS (19 diagnosed according to MRI and one in whom there had been no abnormal findings), 4 with tumors and 1 with a ballooned cell

  12. Developmental Defects of Enamel : an increasing reality in the everyday practice

    Directory of Open Access Journals (Sweden)

    Fabrizio Guerra

    2014-09-01

    Full Text Available Developmental defects of enamel (DDE are daily encountered in clinical practice. DDE are alteration in quality and quantity of the enamel, caused by disruption and/or damage to the enamel organ during the amelogenesis process. Several clinical indices have been developed to categorize enamel defects based on their nature, appearance, microscopic features or their cause. The aetiology of DDE is not completely clear. Enamel fluorosis is a hypo-mineralization of enamel characterised by subsurface porosity as a result of excess fluoride intake during the period of enamel formation. Several types of treatment have been reported, related to the degree of enamel defect. Correct diagnosis according to lesion depth and prognosis of the technique are fundamental factors in the treatment decision-making process.

  13. The influence of the Nd:YAG laser bleaching on physical and mechanical properties of the dental enamel.

    Science.gov (United States)

    Marcondes, Maurem; Paranhos, Maria Paula Gandolfi; Spohr, Ana Maria; Mota, Eduardo Gonçalves; da Silva, Isaac Newton Lima; Souto, André Arigony; Burnett, Luiz Henrique

    2009-07-01

    The Nd:YAG laser can be used in Dentistry to remove soft tissue, disinfect canals in endodontic procedures and prevent caries. However, there is no protocol for Nd:YAG laser application in dental bleaching. The aims of this in vitro study were: (a) to observe the tooth shade alteration when hydrogen peroxide whitening procedures are associated with dyes with different wavelengths and irradiated with Nd:YAG laser or halogen light; (b) to measure the Vickers (VHN) enamel microhardness before and after the whitening procedure; (c) to evaluate the tensile bond strength of two types of adhesive systems applied on bleached enamel; (d) to observe the failure pattern after bond strength testing; (e) to evaluate the pulpal temperature during the bleaching procedures with halogen light or laser; (f) to measure the kinetic reaction of hydrogen peroxide. Extracted sound human molar crowns were sectioned in the mesiodistal direction to obtain 150 fragments that were divided into five groups for each adhesive system: WL (H(2)O(2) + thickener and Nd:YAG), WH (H(2)O(2) + thickener and halogen light), QL (H(2)O(2) + carbopol + Q-switch and Nd:YAG), QH (H(2)O(2) + carbopol + Q-switch and halogen light), and C (Control, without whitening agent). Shade assessment was made with a shade guide and the microhardness tests were performed before and after the bleaching procedures. Immediately afterwards, the groups were restored with the adhesive systems Adper Single Bond 2 or Solobond M plus composite resin, and the tensile bond strength test was performed. The temperature was measured by thermocouples placed on the enamel surface and intrapulpal chamber. The kinetics of hydrogen peroxide was observed by ultraviolet analysis. The shade changed seven levels for Nd:YAG laser groups and eight levels for halogen light. According to the student's t-test, there was no statistical difference between the VHN before and after the whitening protocols (p > 0.05). The tensile bond strength showed no

  14. Digitizing a sound archive

    DEFF Research Database (Denmark)

    Cone, Louise

    2017-01-01

    Danish and international artists. His methodology left us with a large collection of unique and inspirational time-based media sound artworks that have, until very recently, been inaccessible. Existing on an array of different media formats, such as open reel tapes, 8-track and 4 track cassettes, VHS......In 1990 an artist by the name of William Louis Sørensen was hired by the National Gallery of Denmark to collect important works of art – made from sound. His job was to acquire sound art, but also recordings that captured rare artistic occurrences, music, performances and happenings from both...

  15. Innovative Approaches to Regenerate Enamel and Dentin

    Directory of Open Access Journals (Sweden)

    Xanthippi Chatzistavrou

    2012-01-01

    Full Text Available The process of tooth mineralization and the role of molecular control of cellular behavior during embryonic tooth development have attracted much attention the last few years. The knowledge gained from the research in these fields has improved the general understanding about the formation of dental tissues and the entire tooth and set the basis for teeth regeneration. Tissue engineering using scaffold and cell aggregate methods has been considered to produce bioengineered dental tissues, while dental stem/progenitor cells, which can differentiate into dental cell lineages, have been also introduced into the field of tooth mineralization and regeneration. Some of the main strategies for making enamel, dentin, and complex tooth-like structures are presented in this paper. However, there are still significant barriers that obstruct such strategies to move into the regular clinic practice, and these should be overcome in order to have the regenerative dentistry as the important mean that can treat the consequences of tooth-related diseases.

  16. Year of birth determination using radiocarbon dating of dental enamel.

    Science.gov (United States)

    Buchholz, B A; Spalding, K L

    2010-05-01

    Radiocarbon dating is typically an archaeological tool rather than a forensic one. Recently however, we have shown that the amount of radiocarbon present in tooth enamel, as a result of nuclear bomb testing during the cold war, is a remarkably accurate indicator of when a person is born. Enamel isolated from human teeth is processed to form graphite and carbon-14 ((14)C) levels are measured using accelerator mass spectrometry. Since there is no turnover of enamel after it is formed, (14)C levels in the enamel represent (14)C levels in the atmosphere at the time of its formation. In this paper we describe the strategy used to determine the date of birth of an individual based on radiocarbon levels in tooth enamel, focusing on the methodology of this strategy. Year of birth information can significantly assist police investigators when the identity of a deceased individual is unknown. In such cases police will try to match particulars of the unidentified individual (which is often only gender and/or an estimate of age), with particulars from missing persons lists.

  17. Enzyme replacement prevents enamel defects in hypophosphatasia mice

    Science.gov (United States)

    Yadav, Manisha C.; de Oliveira, Rodrigo Cardoso; Foster, Brian L.; Fong, Hanson; Cory, Esther; Narisawa, Sonoko; Sah, Robert L.; Somerman, Martha; Whyte, Michael P.; Millán, José Luis

    2012-01-01

    Hypophosphatasia (HPP) is the inborn error of metabolism characterized by deficiency of alkaline phosphatase activity leading to rickets or osteomalacia and to dental defects. HPP occurs from loss-of-function mutations within the gene that encodes the tissue-nonspecific isozyme of alkaline phosphatase (TNAP). TNAP knockout (Alpl−/−, a.k.a. Akp2−/−) mice closely phenocopy infantile HPP, including the rickets, vitamin B6-responsive seizures, improper dentin mineralization, and lack of acellular cementum. Here, we report that lack of TNAP in Alpl−/− mice also causes severe enamel defects, which are preventable by enzyme replacement with mineral-targeted TNAP (ENB-0040). Immunohistochemistry was used to map the spatiotemporal expression of TNAP in the tissues of the developing enamel organ of healthy mouse molars and incisors. We found strong, stage-specific expression of TNAP in ameloblasts. In the Alpl−/− mice, histological, μCT, and scanning electron microscopy analysis showed reduced mineralization and disrupted organization of the rods and inter-rod structures in enamel of both the molars and incisors. All of these abnormalities were prevented in mice receiving from birth daily subcutaneous injections of mineral-targeting, human TNAP (sALP-FcD10, a.k.a. ENB-0040) at 8.2 mg/kg/day for up to 44 days. These data reveal an important role for TNAP in enamel mineralization, and demonstrate the efficacy of mineral-targeted TNAP to prevent enamel defects in HPP. PMID:22461224

  18. Solubility and diffusivity of hydrogen in enameling steel

    Energy Technology Data Exchange (ETDEWEB)

    De Gregorio, P.; Valentini, R.; Solina, A.; Gastaldo, F. (Centro Sviluppo Materiali, Rome (Italy) Pisa Univ. (Italy). Dip. di Ingegneria Chimica, Chimica Industriale e Scienza dei Materiali)

    1991-06-01

    In recent years, continuous casting has almost expelled conventional ingot casting from the steel-making process by its much higher productivity. However, enameling steel sheets doesn't give the steel sufficient resistance to fishscale, as that which is achieved by the inclusions in case of ingot capped steel. Fishscales are caused by hydrogen gas building up pressure at the interface between enamel and steel, resulting in the rupture of enamel. Object of this study, was not only to correlate fishscale susceptibility with metallurgical parameters, but to define the effect of reversible and irreversible traps on hydrogen solubility and diffusivity in enameling steel. Hydrogen permeation was studied, in low carbon enameling steel, with an electrochemical technique developed by Devanathan and co-workers. This method was used to calculate concentrations of irreversibly adsorbed hydrogen and evaluate hydrogen diffusion coefficients. The results on reversible traps correlated with micro-voids formations around the carbide precipitate, while the irreversible traps correlated with inclusions and precipitate content.

  19. Enamel formation and growth in non-mammalian cynodonts

    Science.gov (United States)

    Dirks, Wendy; Martinelli, Agustín G.

    2018-01-01

    The early evolution of mammals is associated with the linked evolutionary origin of diphyodont tooth replacement, rapid juvenile growth and determinate adult growth. However, specific relationships among these characters during non-mammalian cynodont evolution require further exploration. Here, polarized light microscopy revealed incremental lines, resembling daily laminations of extant mammals, in histological sections of enamel in eight non-mammalian cynodont species. In the more basal non-probainognathian group, enamel extends extremely rapidly from cusp to cervix. By contrast, the enamel of mammaliamorphs is gradually accreted, with slow rates of crown extension, more typical of the majority of non-hypsodont crown mammals. These results are consistent with the reduction in dental replacement rate across the non-mammalian cynodont lineage, with greater rates of crown extension required in most non-probainognathians, and slower crown extension rates permitted in mammaliamorphs, which have reduced patterns of dental replacement in comparison with many non-probainognathians. The evolution of mammal-like growth patterns, with faster juvenile growth and more abruptly terminating adult growth, is linked with this reduction in dental replacement rates and may provide an additional explanation for the observed pattern in enamel growth rates. It is possible that the reduction in enamel extension rates in mammaliamorphs reflects an underlying reduction in skeletal growth rates at the time of postcanine formation, due to a more abruptly terminating pattern of adult growth in these more mammal-like, crownward species. PMID:29892415

  20. Amelogenesis Imperfect, Enamel Hypoplasia and Fluorosis Dental - Literature Review

    Directory of Open Access Journals (Sweden)

    Flávia Magnani Bevilacqua

    2015-12-01

    Full Text Available The developmental disorders of enamel are abnormalities of structure which can affect both dentitions. These abnormalities include amelogenesis imperfecta, enamel hypoplasia and dental fluorosis. The amelogenesis imperfecta is a hereditary change and enamel hypoplasia is a quantitative defect of enamel that occurs as a result of systemic problems, local and also inherited factors, or even the combination of them. Dental fluorosis is a hypoplasia caused by the chronic ingestion of fluoride during odontogenesis. All these anomalies have similar clinical characteristics, and it is necessary to be careful in their assessment. It is extremely important to know these abnormalities to establish a differential diagnosis and, consequently, a treatment plan, which can be set for each situation. Therefore, the purpose of this study was to review the literature regarding these three anomalies: amelogenesis imperfecta, enamel hypoplasia and dental fluorosis. It was concluded that to establish the differential diagnosis of these abnormalities as well as a proper treatment plan, it is indispensable the professional knowledge associated with the clinical examination. The examination has to consist of medical history and physical examination, and in some cases, x-ray examination.

  1. Indentation damage and crack repair in human enamel.

    Science.gov (United States)

    Rivera, C; Arola, D; Ossa, A

    2013-05-01

    Tooth enamel is the hardest and most highly mineralized tissue in the human body. While there have been a number of studies aimed at understanding the hardness and crack growth resistance behavior of this tissue, no study has evaluated if cracks in this tissue undergo repair. In this investigation the crack repair characteristics of young human enamel were evaluated as a function of patient gender and as a function of the distance from the Dentin Enamel Junction (DEJ). Cracks were introduced via microindentation along the prism direction and evaluated as a function of time after the indentation. Microscopic observations indicated that the repair of cracks began immediately after crack initiation and reaches saturation after approximately 48 h. During this process he crack length decreased up to 10% of the initial length, and the largest degree of reduction occurred in the deep enamel, nearest the DEJ. In addition, it was found that the degree of repair was significantly greater in the enamel of female patients. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Indentation Damage and Crack Repair in Human Enamel*

    Science.gov (United States)

    Rivera, C.; Arola, D.; Ossa, A.

    2013-01-01

    Tooth enamel is the hardest and most highly mineralized tissue in the human body. While there have been a number of studies aimed at understanding the hardness and crack growth resistance behavior of this tissue, no study has evaluated if cracks in this tissue undergo repair. In this investigation the crack repair characteristics of young human enamel were evaluated as a function of patient gender and as a function of the distance from the Dentin Enamel Junction (DEJ). Cracks were introduced via microindentation along the prism direction and evaluated as a function of time after the indentation. Microscopic observations indicated that the repair of cracks began immediately after crack initiation and reaches saturation after approximately 48 hours. During this process he crack length decreased up to 10% of the initial length, and the largest degree of reduction occurred in the deep enamel, nearest the DEJ. In addition, it was found that the degree of repair was significantly greater in the enamel of female patients. PMID:23541701

  3. Year of Birth Determination Using Radiocarbon Dating of Dental Enamel

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, B A; Spalding, K L

    2009-03-10

    Radiocarbon dating is typically an archaeological tool rather than a forensic one. Recently however, we have shown that the amount of radiocarbon present in tooth enamel, as a result of nuclear bomb testing during the cold war, is a remarkably accurate indicator of when a person is born. Enamel isolated from human teeth is processed to form graphite and carbon-14 ({sup 14}C) levels are measured using accelerator mass spectrometry. Since there is no turnover of enamel after it is formed, {sup 14}C levels in the enamel represent {sup 14}C levels in the atmosphere at the time of its formation. In this paper we describe the strategy used to determine the date of birth of an individual based on radiocarbon levels in tooth enamel, focusing on the methodology of this strategy. Year of birth information can significantly assist police investigators when the identity of a deceased individual is unknown. In such cases police will try to match particulars of the unidentified individual (which is often only gender and/or an estimate of age), with particulars from missing persons lists.

  4. Sounds of Web Advertising

    DEFF Research Database (Denmark)

    Jessen, Iben Bredahl; Graakjær, Nicolai Jørgensgaard

    2010-01-01

    Sound seems to be a neglected issue in the study of web ads. Web advertising is predominantly regarded as visual phenomena–commercial messages, as for instance banner ads that we watch, read, and eventually click on–but only rarely as something that we listen to. The present chapter presents...... an overview of the auditory dimensions in web advertising: Which kinds of sounds do we hear in web ads? What are the conditions and functions of sound in web ads? Moreover, the chapter proposes a theoretical framework in order to analyse the communicative functions of sound in web advertising. The main...... argument is that an understanding of the auditory dimensions in web advertising must include a reflection on the hypertextual settings of the web ad as well as a perspective on how users engage with web content....

  5. Sound Art Situations

    DEFF Research Database (Denmark)

    Krogh Groth, Sanne; Samson, Kristine

    2017-01-01

    and combine theories from several fields. Aspects of sound art studies, performance studies and contemporary art studies are presented in order to theoretically explore the very diverse dimensions of the two sound art pieces: Visual, auditory, performative, social, spatial and durational dimensions become......This article is an analysis of two sound art performances that took place June 2015 in outdoor public spaces in the social housing area Urbanplanen in Copenhagen, Denmark. The two performances were On the production of a poor acoustics by Brandon LaBelle and Green Interactive Biofeedback...... Environments (GIBE) by Jeremy Woodruff. In order to investigate the complex situation that arises when sound art is staged in such contexts, the authors of this article suggest exploring the events through approaching them as ‘situations’ (Doherty 2009). With this approach it becomes possible to engage...

  6. Sound as Popular Culture

    DEFF Research Database (Denmark)

    The wide-ranging texts in this book take as their premise the idea that sound is a subject through which popular culture can be analyzed in an innovative way. From an infant’s gurgles over a baby monitor to the roar of the crowd in a stadium to the sub-bass frequencies produced by sound systems...... in the disco era, sound—not necessarily aestheticized as music—is inextricably part of the many domains of popular culture. Expanding the view taken by many scholars of cultural studies, the contributors consider cultural practices concerning sound not merely as semiotic or signifying processes but as material......, physical, perceptual, and sensory processes that integrate a multitude of cultural traditions and forms of knowledge. The chapters discuss conceptual issues as well as terminologies and research methods; analyze historical and contemporary case studies of listening in various sound cultures; and consider...

  7. It sounds good!

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Both the atmosphere and we ourselves are hit by hundreds of particles every second and yet nobody has ever heard a sound coming from these processes. Like cosmic rays, particles interacting inside the detectors at the LHC do not make any noise…unless you've decided to use the ‘sonification’ technique, in which case you might even hear the Higgs boson sound like music. Screenshot of the first page of the "LHC sound" site. A group of particle physicists, composers, software developers and artists recently got involved in the ‘LHC sound’ project to make the particles at the LHC produce music. Yes…music! The ‘sonification’ technique converts data into sound. “In this way, if you implement the right software you can get really nice music out of the particle tracks”, says Lily Asquith, a member of the ATLAS collaboration and one of the initiators of the project. The ‘LHC...

  8. Sound Visualization and Holography

    Science.gov (United States)

    Kock, Winston E.

    1975-01-01

    Describes liquid surface holograms including their application to medicine. Discusses interference and diffraction phenomena using sound wave scanning techniques. Compares focussing by zone plate to holographic image development. (GH)

  9. The impact of fluoride on ameloblasts and the mechanisms of enamel fluorosis

    NARCIS (Netherlands)

    Bronckers, A.L.J.J.; Lyaruu, D.M.; Denbesten, P.K.

    2009-01-01

    Intake of excess amounts of fluoride during tooth development cause enamel fluorosis, a developmental disturbance that makes enamel more porous. In mild fluorosis, there are white opaque striations across the enamel surface, whereas in more severe cases, the porous regions increase in size, with

  10. Study of the arrangement of crystallites in γ-irradiated human enamel by electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Cevc, P.; Schara, M.; Ravnik, C.; Skaleric, U.

    1976-01-01

    The arrangement of tooth enamel microcrystals has been studied on CO 3 3- bound electrons by paramagnetic resonance. It was found that noncarious human maxillary central incisors have a greater degree of alignment of tooth enamel microcrystals than the carious ones. The outermost surface layer of enamel showed a greater crystallite degree of alignment than other parts

  11. Type VII collagen is enriched in the enamel organic matrix associated with the dentin-enamel junction of mature human teeth.

    Science.gov (United States)

    McGuire, Jacob D; Walker, Mary P; Mousa, Ahmad; Wang, Yong; Gorski, Jeff P

    2014-06-01

    The inner enamel region of erupted teeth is known to exhibit higher fracture toughness and crack growth resistance than bulk phase enamel. However, an explanation for this behavior has been hampered by the lack of compositional information for the residual enamel organic matrix. Since enamel-forming ameloblasts are known to express type VII collagen and type VII collagen null mice display abnormal amelogenesis, the aim of this study was to determine whether type VII collagen is a component of the enamel organic matrix at the dentin-enamel junction (DEJ) of mature human teeth. Immunofluorescent confocal microscopy of demineralized tooth sections localized type VII collagen to the organic matrix surrounding individual enamel rods near the DEJ. Morphologically, immunoreactive type VII collagen helical-bundles resembled the gnarled-pattern of enamel rods detected by Coomassie Blue staining. Western blotting of whole crown or enamel matrix extracts also identified characteristic Mr=280 and 230 kDa type VII dimeric forms, which resolved into 75 and 25 kDa bands upon reduction. As expected, the collagenous domain of type VII collagen was resistant to pepsin digestion, but was susceptible to purified bacterial collagenase. These results demonstrate the inner enamel organic matrix in mature teeth contains macromolecular type VII collagen. Based on its physical association with the DEJ and its well-appreciated capacity to complex with other collagens, we hypothesize that enamel embedded type VII collagen fibrils may contribute not only to the structural resilience of enamel, but may also play a role in bonding enamel to dentin. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Pb enamel biomarker: Deposition of pre- and postnatal Pb isotope injection in reconstructed time points along rat enamel transect

    International Nuclear Information System (INIS)

    Rinderknecht, A.L.; Kleinman, M.T.; Ericson, J.E.

    2005-01-01

    Exposure to lead (Pb) as well as other heavy metals in the environment is still a matter of public health concern. The development of the enamel biomarker for heavy metal exposure assessment is designed to improve studies of dose-effect relationships to developmental anomalies, particularly embryonic dysfunctions, and to provide a time-specific recount of past exposures. The work presented in this paper demonstrates maternal transfer across the placental barrier of the enriched isotope 206 Pb tracer to the enamel of the rat pup. Likewise, injections of 204 Pb-enriched tracer in the neonate rat resulted in deposition of the tracer in the enamel histology as measured by secondary ion microprobe spectrometry. Through enamel, we were able to observe biological removal and assimilation of prenatal and postnatal tracers, respectively. This research demonstrates that enamel can be used as a biomarker of exposure to Pb and may illustrate the toxicokinetics of incorporating Pb into fetal and neonatal steady-state system processes. The biomarker technique, when completely developed, may be applied to cross-sectional and longitudinal epidemiological research

  13. The Chernobyl accident: EPR dosimetry on dental enamel of children

    International Nuclear Information System (INIS)

    Gualtieri, G.; Colacicchi, S.; Sgattoni, R.; Giannoni, M.

    2001-01-01

    The radiation dose on tooth enamel of children living close to Chernobyl has been evaluated by EPR. The sample preparation was reduced to a minimum of mechanical steps to remove a piece of enamel. A standard X-ray tube at low energy was used for additive irradiation. The filtration effect of facial soft tissue was taken into account. The radiation dose for a group of teeth slightly exceeds the annual dose, whereas for another group the dose very much exceeds the annual dose. Since the higher dose is found in teeth whose enamel have much lower EPR sensitivity to the radiation, it can be suggested that for these teeth the native signal could alter the evaluation of the smaller radiation signal

  14. Evaluation of the bleached human enamel by Scanning Electron Microscopy

    DEFF Research Database (Denmark)

    Miranda, Carolina Baptista; Pagani, Clovis; Benetti, Ana Raquel

    2005-01-01

    Since bleaching has become a popular procedure, the effect of peroxides on dental hard tissues is of great interest in research. Purpose: The aim of this in vitro study was to perform a qualitative analysis of the human enamel after the application of in-office bleaching agents, using Scanning......: 2h); G3- four 2-hour exposures to 35% carbamide peroxide (total exposure: 8h); G4- two applications of 35% hydrogen peroxide, which was light-activated with halogen lamp at 700mW/cm² during 7min and remained in contact with enamel for 20min (total exposure: 40min). All bleaching treatments adopted...... analysis performing gold sputter coating under vacuum and were examined using 15kV at 500x and 2000x magnification. Results: Morphological alterations on the enamel surface were similarly detected after bleaching with either 35% carbamide peroxide or 35% hydrogen peroxide. Surface porosities were...

  15. The efficiency of child formula dentifrices containing different calcium and phosphate compounds on artificial enamel caries.

    Science.gov (United States)

    Rirattanapong, Praphasri; Vongsavan, Kadkao; Saengsirinavin, Chavengkiat; Khumsub, Ploychompoo

    2016-01-01

    Fluoride toothpaste has been extensively used to prevent dental caries. However, the risk of fluorosis is concerning, especially in young children. Calcium phosphate has been an effective remineralizing agent and is present in commercial dental products, with no risk of fluorosis to users. This in vitro study aimed to compare the effects of different calcium phosphate compounds and fluoride-containing dentifrices on artificial caries in primary teeth. Fifty sound primary incisors were coated with nail varnish, leaving two 1 mm 2 windows on the labial surface before immersion in demineralizing solution for 96 hours to produce artificial enamel lesions. Subsequently, one window from each tooth was coated with nail varnish, and all 50 teeth were divided into five groups ( n = 10); group A - deionized water; group B - casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste (Tooth Mousse); group C - 500 ppm F (Colgate Spiderman ® ); group D - nonfluoridated toothpaste with triple calcium phosphate (Pureen ® ); and group E - tricalcium phosphate (TCP). Polarized light microscopy and Image-Pro ® Plus software were used to evaluate lesions. After a 7-day pH-cycle, mean lesion depths in groups A, B, C, D, and E had increased by 57.52 ± 10.66%, 33.28 ± 10.16%, 17.04 ± 4.76%, 32.51 ± 8.99%, and 21.76 ± 8.15%, respectively. All data were processed by the Statistical Package for the Social Sciences (version 16.0) software package. Comparison of percentage changes using one-way analysis of variance and Fisher's least squares difference tests at a 95% level of confidence demonstrated that group A was significantly different from the other groups ( P < 0.001). Lesions in groups B and D had a significant lesion progression when compared with groups C and E. All toothpastes in this study had the potential to delay the demineralization progression of artificial enamel caries in primary teeth. The fluoride 500 ppm and TCP toothpastes were equal in the deceleration of

  16. In Vitro Comparative Study of Two Different Bleaching Agents on Micro-hardness Dental Enamel.

    Science.gov (United States)

    Fatima, Nazish; Ali Abidi, Syed Yawar; Meo, Ashraf Ali

    2016-02-01

    To evaluate the effect of home-use bleaching agent containing 16% Carbamide Peroxide (CP) and in-office bleaching agent containing 38% Hydrogen Peroxide (HP) on enamel micro-hardness. An in vitroexperimental study. Department of Operative Dentistry and Science of Dental Materials at Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences and Material Engineering Department of NED University of Engineering and Technology, Karachi, from July to December 2014. Atotal of 90 enamel slabs from 45 sound human 3rd molar were randomly divided into 3 groups. Each group contained 30 specimens (n=30). Group 1 was kept in artificial saliva at 37°C in incubator during the whole experiment. However, Groups 2 and 3 were treated with power whitening gel and tooth whitening pen respectively. After bleaching session, specimens were thoroughly rinsed with deionized water again for 10 seconds and then stored in artificial saliva at 37°C in incubator. Artificial saliva was changed after every 2 days. The Vickers hardness tester (Wolpert 402 MVD, Germany) was adjusted to a load of 0.1 kg (100 gm) and dwell time of 5 seconds. Three Vickers were performed on each specimen using a hardness tester according to the ISO 6507-3:1998 specification. Micro-hardness measurements were performed before and after bleaching at day 1, 7 and 14. In the control group, the baseline micro-hardness was 181.1 ±9.3 which was reduced after the storage on day 1, 7 and 14 (p = 0.104). In Group 2, baseline micro-hardness was 180.4 ±10.1 which was reduced to 179.79 ±10.0 units after day 1. Whereas, on day 7 and 14, the values of micro-hardness were 179.8 ±10 and 179.7 ±10.29, respectively (p=0.091). Furthermore, the baseline micro-hardness in Group 3 was 174.0 ±22.9 units which was reduced to 173 ±23 on day 1, 170 ±30 on day 7 and 173 ±23 on day 14 (p = 0.256). The statistically insignificant difference was found among micro-hardness values of different bleaching

  17. In Vitro Comparative Study of Two Different Bleaching Agents on Micro-hardness Dental Enamel

    International Nuclear Information System (INIS)

    Fatima, N.; Abidi, S. Y. A.; Meo, A. A.

    2016-01-01

    Objective: To evaluate the effect of home-use bleaching agent containing 16 percentage Carbamide Peroxide (CP) and in-office bleaching agent containing 38 percentage Hydrogen Peroxide (HP) on enamel micro-hardness. Study Design: An in vitro experimental study. Place and Duration of Study: Department of Operative Dentistry and Science of Dental Materials at Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences and Material Engineering Department of NED University of Engineering and Technology, Karachi, from July to December 2014. Methodology: A total of 90 enamel slabs from 45 sound human 3rd molar were randomly divided into 3 groups. Each group contained 30 specimens (n=30). Group 1 was kept in artificial saliva at 37 Degree C in incubator during the whole experiment. However, Groups 2 and 3 were treated with power whitening gel and tooth whitening pen respectively. After bleaching session, specimens were thoroughly rinsed with deionized water again for 10 seconds and then stored in artificial saliva at 37 Degree C in incubator. Artificial saliva was changed after every 2 days. The Vickers hardness tester (Wolpert 402 MVD, Germany) was adjusted to a load of 0.1 kg (100 gm) and dwell time of 5 seconds. Three Vickers were performed on each specimen using a hardness tester according to the ISO 6507-3:1998 specification. Micro-hardness measurements were performed before and after bleaching at day 1, 7 and 14. Results: In the control group, the baseline micro-hardness was 181.1 ± 9.3 which was reduced after the storage on day 1, 7 and 14 (p = 0.104). In Group 2, baseline micro-hardness was 180.4 ±10.1 which was reduced to 179.79 ± 10.0 units after day 1. Whereas, on day 7 and 14, the values of micro-hardness were 179.8 ±10 and 179.7 ±10.29, respectively (p=0.091). Furthermore, the baseline micro-hardness in Group 3 was 174.0 ±22.9 units which was reduced to 173 ± 23 on day 1, 170 ±30 on day 7 and 173 ± 23 on day 14 (p = 0

  18. Enamel thickness after preparation of tooth for porcelain laminate.

    Science.gov (United States)

    Pahlevan, Ayoub; Mirzaee, Mansoreh; Yassine, Esmaeil; Ranjbar Omrany, Ladan; Hasani Tabatabaee, Masumeh; Kermanshah, Hamid; Arami, Sakineh; Abbasi, Mehdy

    2014-07-01

    In this investigation the thickness of enamel in the gingival, middle, and incisal thirds of the labial surface of the anterior teeth were measured regarding preparation of the teeth for porcelain laminate veneers. Part one, 20 extracted intact human maxillary central and lateral incisors ten of each were selected. The teeth were imbedded in autopolimerize acrylic resin. Cross section was preformed through the midline of the incisal, middle and cervical one-third of the labial surface of the teeth. The samples were observed under reflected stereomicroscope and the thickness of enamel was recorded. Part II, the effect of different types of preparation on dentin exposure was evaluated. Thirty maxillary central incisor teeth were randomly divided into two groups: A: Knife-edge preparation. B: Chamfer preparation. All samples were embedded in autopolimerize acrylic resin using a silicon mold. The samples were cut through the midline of the teeth. The surface of the samples were polished and enamel and dentin were observed under the stereomicroscope. Data were analyzed by ANOVA-one way test. The results of this study showed that the least enamel thickness in the central incisor was 345 and in lateral incisor is 235 μ this thickness is related to the one-third labial cervical area. Maximum thickness in maxillary central and lateral incisors in the one-third labial incisal surface was 1260 μ and 1220μ, respectively. In the second part of the study, the tendency of dentinal exposure was shown with the chamfer preparation, but no dentinal exposure was found in the knife-edge preparation. The differences between groups were significant (p<0.05). The knowledge of enamel thickness in different part of labial surface is very important. The thickness of enamel in the gingival area does not permit a chamfer preparation. The knife edge preparation is preferable in gingival area.

  19. Enamel thickness after preparation of tooth for porcelain laminate.

    Directory of Open Access Journals (Sweden)

    Ayoub Pahlevan

    2014-08-01

    Full Text Available In this investigation the thickness of enamel in the gingival, middle, and incisal thirds of the labial surface of the anterior teeth were measured regarding preparation of the teeth for porcelain laminate veneers.Part one, 20 extracted intact human maxillary central and lateral incisors ten of each were selected. The teeth were imbedded in autopolimerize acrylic resin. Cross section was preformed through the midline of the incisal, middle and cervical one-third of the labial surface of the teeth. The samples were observed under reflected stereomicroscope and the thickness of enamel was recorded. Part II, the effect of different types of preparation on dentin exposure was evaluated. Thirty maxillary central incisor teeth were randomly divided into two groups: A: Knife-edge preparation. B: Chamfer preparation. All samples were embedded in autopolimerize acrylic resin using a silicon mold. The samples were cut through the midline of the teeth. The surface of the samples were polished and enamel and dentin were observed under the stereomicroscope.Data were analyzed by ANOVA-one way test. The results of this study showed that the least enamel thickness in the central incisor was 345 and in lateral incisor is 235 μ this thickness is related to the one-third labial cervical area. Maximum thickness in maxillary central and lateral incisors in the one-third labial incisal surface was 1260 μ and 1220μ, respectively. In the second part of the study, the tendency of dentinal exposure was shown with the chamfer preparation, but no dentinal exposure was found in the knife-edge preparation. The differences between groups were significant (p<0.05.The knowledge of enamel thickness in different part of labial surface is very important. The thickness of enamel in the gingival area does not permit a chamfer preparation. The knife edge preparation is preferable in gingival area.

  20. Quantitative analysis of enamel on debonded orthodontic brackets.

    Science.gov (United States)

    Cochrane, Nathan J; Lo, Thomas W G; Adams, Geoffrey G; Schneider, Paul M

    2017-09-01

    Iatrogenic damage to the tooth surface in the form of enamel tearouts can occur during removal of fixed orthodontic appliances. The aim of this study was to assess debonded metal and ceramic brackets attached with a variety of bonding materials to determine how frequently this type of damage occurs. Eighty-one patients close to finishing fixed orthodontic treatment were recruited. They had metal brackets bonded with composite resin and a 2-step etch-and-bond technique or ceramic brackets bonded with composite resin and a 2-step etch-and- bond technique, and composite resin with a self-etching primer or resin-modified glass ionomer cement. Debonded brackets were examined by backscattered scanning electron microscopy with energy dispersive x-ray spectroscopy to determine the presence and area of enamel on the base pad. Of the 486 brackets collected, 26.1% exhibited enamel on the bonding material on the bracket base pad. The incidences of enamel tearouts for each group were metal brackets, 13.3%; ceramic brackets, 30.2%; composite resin with self-etching primer, 38.2%; and resin-modified glass ionomer cement, 21.2%. The percentage of the bracket base pad covered in enamel was highly variable, ranging from 0% to 46.1%. Enamel damage regularly occurred during the debonding process with the degree of damage being highly variable. Damage occurred more frequently when ceramic brackets were used (31.9%) compared with metal brackets (13.3%). Removal of ceramic brackets bonded with resin-modified glass ionomer cement resulted in less damage compared with the resin bonding systems. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  1. Recovery of crystallographic texture in remineralized dental enamel.

    Science.gov (United States)

    Siddiqui, Samera; Anderson, Paul; Al-Jawad, Maisoon

    2014-01-01

    Dental caries is the most prevalent disease encountered by people of all ages around the world. Chemical changes occurring in the oral environment during the caries process alter the crystallography and microstructure of dental enamel resulting in loss of mechanical function. Little is known about the crystallographic effects of demineralization and remineralization. The motivation for this study was to develop understanding of the caries process at the crystallographic level in order to contribute towards a long term solution. In this study synchrotron X-ray diffraction combined with scanning electron microscopy and scanning microradiography have been used to correlate enamel crystallography, microstructure and mineral concentration respectively in enamel affected by natural caries and following artificial demineralization and remineralization regimes. In particular, the extent of destruction and re-formation of this complex structure has been measured. 2D diffraction patterns collected at the European Synchrotron Radiation Facility were used to quantify changes in the preferred orientation (crystallographic texture) and position of the (002) Bragg reflection within selected regions of interest in each tooth slice, and then correlated with the microstructure and local mineral mass. The results revealed that caries and artificial demineralization cause a large reduction in crystallographic texture which is coupled with the loss of mineral mass. Remineralization restores the texture to the original level seen in healthy enamel and restores mineral density. The results also showed that remineralization promotes ordered formation of new crystallites and growth of pre-existing crystallites which match the preferred orientation of healthy enamel. Combining microstructural and crystallographic characterization aids the understanding of caries and erosion processes and assists in the progress towards developing therapeutic treatments to allow affected enamel to regain

  2. Electron paramagnetic resonance biophysical radiation dosimetry with tooth enamel

    International Nuclear Information System (INIS)

    Khan, Rao F.H.

    2003-01-01

    This thesis deals with the advancements made in the field of Electron Paramagnetic Resonance (EPR) for biophysical dosimetry with tooth enamel for accident, emergency, and retrospective radiation dose reconstruction. A methodology has been developed to measure retrospective radiation exposures in human tooth enamel. This entails novel sample preparation procedures with minimum mechanical treatment to reduce the preparation induced uncertainties, establish optimum measurement conditions inside the EPR cavity, post-process the measured spectrum with functional simulation of dosimetric and other interfering signals, and reconstruct dose. By using this technique, retrospective gamma exposures as low as 80±30 mGy have been successfully deciphered. The notion of dose modifier was introduced in EPR biodosimetry for low dose measurements. It has been demonstrated that by using the modified zero added dose (MZAD) technique for low radiation exposures, doses in 100 mGy ranges can be easily reconstructed in teeth that were previously thought useless for EPR dosimetry. Also, the use of a dose modifier makes robust dose reconstruction possible for higher radiation exposures. The EPR dosimetry technique was also developed for tooth samples extracted from rodents, which represent small tooth sizing. EPR doses in the molars, extracted from the mice irradiated with whole body exposures, were reassessed and shown to be correct within the experimental uncertainty. The sensitivity of human tooth enamel for neutron irradiation, obtained from the 3 MV McMaster K.N. Van de Graaff accelerator, was also studied. For the first time this work has shown that the neutron sensitivity of the tooth enamel is approximately 1/10th of the equivalent gamma sensitivity. Parametric studies for neutron dose rate and neutron energy within the available range of the accelerator, showed no impact on the sensitivity of the tooth enamel. Therefore, tooth enamel can be used as a dosimeter for both neutrons

  3. Enamel ultrastructure in fossil cetaceans (Cetacea: Archaeoceti and Odontoceti.

    Directory of Open Access Journals (Sweden)

    Carolina Loch

    Full Text Available The transition from terrestrial ancestry to a fully pelagic life profoundly altered the body systems of cetaceans, with extreme morphological changes in the skull and feeding apparatus. The Oligocene Epoch was a crucial time in the evolution of cetaceans when the ancestors of modern whales and dolphins (Neoceti underwent major diversification, but details of dental structure and evolution are poorly known for the archaeocete-neocete transition. We report the morphology of teeth and ultrastructure of enamel in archaeocetes, and fossil platanistoids and delphinoids, ranging from late Oligocene (Waitaki Valley, New Zealand to Pliocene (Caldera, Chile. Teeth were embedded in epoxy resin, sectioned in cross and longitudinal planes, polished, etched, and coated with gold palladium for scanning electron microscopy (SEM observation. SEM images showed that in archaeocetes, squalodontids and Prosqualodon (taxa with heterodont and nonpolydont/limited polydont teeth, the inner enamel was organized in Hunter-Schreger bands (HSB with an outer layer of radial enamel. This is a common pattern in most large-bodied mammals and it is regarded as a biomechanical adaptation related to food processing and crack resistance. Fossil Otekaikea sp. and delphinoids, which were polydont and homodont, showed a simpler structure, with inner radial and outer prismless enamel. Radial enamel is regarded as more wear-resistant and has been retained in several mammalian taxa in which opposing tooth surfaces slide over each other. These observations suggest that the transition from a heterodont and nonpolydont/limited polydont dentition in archaeocetes and early odontocetes, to homodont and polydont teeth in crownward odontocetes, was also linked to a marked simplification in the enamel Schmelzmuster. These patterns probably reflect functional shifts in food processing from shear-and-mastication in archaeocetes and early odontocetes, to pierce-and-grasp occlusion in crownward

  4. Enamel ultrastructure in fossil cetaceans (Cetacea: Archaeoceti and Odontoceti).

    Science.gov (United States)

    Loch, Carolina; Kieser, Jules A; Fordyce, R Ewan

    2015-01-01

    The transition from terrestrial ancestry to a fully pelagic life profoundly altered the body systems of cetaceans, with extreme morphological changes in the skull and feeding apparatus. The Oligocene Epoch was a crucial time in the evolution of cetaceans when the ancestors of modern whales and dolphins (Neoceti) underwent major diversification, but details of dental structure and evolution are poorly known for the archaeocete-neocete transition. We report the morphology of teeth and ultrastructure of enamel in archaeocetes, and fossil platanistoids and delphinoids, ranging from late Oligocene (Waitaki Valley, New Zealand) to Pliocene (Caldera, Chile). Teeth were embedded in epoxy resin, sectioned in cross and longitudinal planes, polished, etched, and coated with gold palladium for scanning electron microscopy (SEM) observation. SEM images showed that in archaeocetes, squalodontids and Prosqualodon (taxa with heterodont and nonpolydont/limited polydont teeth), the inner enamel was organized in Hunter-Schreger bands (HSB) with an outer layer of radial enamel. This is a common pattern in most large-bodied mammals and it is regarded as a biomechanical adaptation related to food processing and crack resistance. Fossil Otekaikea sp. and delphinoids, which were polydont and homodont, showed a simpler structure, with inner radial and outer prismless enamel. Radial enamel is regarded as more wear-resistant and has been retained in several mammalian taxa in which opposing tooth surfaces slide over each other. These observations suggest that the transition from a heterodont and nonpolydont/limited polydont dentition in archaeocetes and early odontocetes, to homodont and polydont teeth in crownward odontocetes, was also linked to a marked simplification in the enamel Schmelzmuster. These patterns probably reflect functional shifts in food processing from shear-and-mastication in archaeocetes and early odontocetes, to pierce-and-grasp occlusion in crownward odontocetes, with

  5. A model for predicting wear rates in tooth enamel.

    Science.gov (United States)

    Borrero-Lopez, Oscar; Pajares, Antonia; Constantino, Paul J; Lawn, Brian R

    2014-09-01

    It is hypothesized that wear of enamel is sensitive to the presence of sharp particulates in oral fluids and masticated foods. To this end, a generic model for predicting wear rates in brittle materials is developed, with specific application to tooth enamel. Wear is assumed to result from an accumulation of elastic-plastic micro-asperity events. Integration over all such events leads to a wear rate relation analogous to Archard׳s law, but with allowance for variation in asperity angle and compliance. The coefficient K in this relation quantifies the wear severity, with an arbitrary distinction between 'mild' wear (low K) and 'severe' wear (high K). Data from the literature and in-house wear-test experiments on enamel specimens in lubricant media (water, oil) with and without sharp third-body particulates (silica, diamond) are used to validate the model. Measured wear rates can vary over several orders of magnitude, depending on contact asperity conditions, accounting for the occurrence of severe enamel removal in some human patients (bruxing). Expressions for the depth removal rate and number of cycles to wear down occlusal enamel in the low-crowned tooth forms of some mammals are derived, with tooth size and enamel thickness as key variables. The role of 'hard' versus 'soft' food diets in determining evolutionary paths in different hominin species is briefly considered. A feature of the model is that it does not require recourse to specific material removal mechanisms, although processes involving microplastic extrusion and microcrack coalescence are indicated. Published by Elsevier Ltd.

  6. Recovery of crystallographic texture in remineralized dental enamel.

    Directory of Open Access Journals (Sweden)

    Samera Siddiqui

    Full Text Available Dental caries is the most prevalent disease encountered by people of all ages around the world. Chemical changes occurring in the oral environment during the caries process alter the crystallography and microstructure of dental enamel resulting in loss of mechanical function. Little is known about the crystallographic effects of demineralization and remineralization. The motivation for this study was to develop understanding of the caries process at the crystallographic level in order to contribute towards a long term solution. In this study synchrotron X-ray diffraction combined with scanning electron microscopy and scanning microradiography have been used to correlate enamel crystallography, microstructure and mineral concentration respectively in enamel affected by natural caries and following artificial demineralization and remineralization regimes. In particular, the extent of destruction and re-formation of this complex structure has been measured. 2D diffraction patterns collected at the European Synchrotron Radiation Facility were used to quantify changes in the preferred orientation (crystallographic texture and position of the (002 Bragg reflection within selected regions of interest in each tooth slice, and then correlated with the microstructure and local mineral mass. The results revealed that caries and artificial demineralization cause a large reduction in crystallographic texture which is coupled with the loss of mineral mass. Remineralization restores the texture to the original level seen in healthy enamel and restores mineral density. The results also showed that remineralization promotes ordered formation of new crystallites and growth of pre-existing crystallites which match the preferred orientation of healthy enamel. Combining microstructural and crystallographic characterization aids the understanding of caries and erosion processes and assists in the progress towards developing therapeutic treatments to allow affected

  7. Effects of etching time on enamel bond strengths.

    Science.gov (United States)

    Triolo, P T; Swift, E J; Mudgil, A; Levine, A

    1993-12-01

    This study evaluated the effects of etching time on bond strengths of composite to enamel. Proximal surfaces of extracted molars were etched with either a conventional etchant (35% phosphoric acid) or one of two dentin/enamel conditioners, 10% maleic acid (Scotchbond Multi-Purpose Etchant), or a solution of oxalic acid, aluminum nitrate, and glycine (Gluma 1 & 2 Conditioner). Each agent was applied for 15, 30, or 60 seconds. Specimens etched with 35% phosphoric acid had the highest mean bond strengths at each etching time. At the manufacturer's recommended application times, the other two agents gave significantly lower shear bond strengths than phosphoric acid.

  8. Inter-proximal enamel reduction in contemporary orthodontics.

    Science.gov (United States)

    Pindoria, J; Fleming, P S; Sharma, P K

    2016-12-16

    Inter-proximal enamel reduction has gained increasing prominence in recent years being advocated to provide space for orthodontic alignment, to refine contact points and to potentially improve long-term stability. An array of techniques and products are available ranging from hand-held abrasive strips to handpiece mounted burs and discs. The indications for inter-proximal enamel reduction and the importance of formal space analysis, together with the various techniques and armamentarium which may be used to perform it safely in both the labial and buccal segments are outlined.

  9. Mammalian enamel maturation: Crystallographic changes prior to tooth eruption

    Czech Academy of Sciences Publication Activity Database

    Kallistová, Anna; Horáček, I.; Šlouf, Miroslav; Skála, Roman; Fridrichová, Michaela

    2017-01-01

    Roč. 12, č. 2 (2017), č. článku e0171424. E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:67985831 ; RVO:61389013 Keywords : resolution electron-microscopy * atomic-force microscopy * dental enamel * vertebrate dentition * rat enamel * protein * evolution * crystals * shape * ameloblastin Subject RIV: EH - Ecology, Behaviour; CD - Macromolecular Chemistry (UMCH-V) OBOR OECD: Other biological topics; Polymer science (UMCH-V) Impact factor: 2.806, year: 2016

  10. Surface changes of enamel after brushing with charcoal toothpaste

    Science.gov (United States)

    Pertiwi, U. I.; Eriwati, Y. K.; Irawan, B.

    2017-08-01

    The aim of this study was to determine the surface roughness changes of tooth enamel after brushing with charcoal toothpaste. Thirty specimens were brushed using distilled water (the first group), Strong® Formula toothpaste (the second group), and Charcoal® Formula toothpaste for four minutes and 40 seconds (equivalent to one month) and for 14 minutes (equivalent to three months) using a soft fleece toothbrush with a mass of 150 gr. The roughness was measured using a surface roughness tester, and the results were tested with repeated ANOVA test and one-way ANOVA. The value of the surface roughness of tooth enamel was significantly different (penamel.

  11. Non-specific esterases in partly mineralized bovine enamel

    DEFF Research Database (Denmark)

    Moe, D; Kirkeby, S

    1990-01-01

    Activity for non-specific esterase was demonstrated in the matrix of developing bovine enamel with alpha-naphthyl acetate and 5-bromoindoxyl acetate as the esterase substrates. By use of high-performance liquid chromatography gel filtration, ion-exchange chromatography, and electrophoresis three...... esterases were shown to be present in the enamel matrix. The enzymes showed highest activity at pH 6.5-7.5. In sections a strong reaction was observed in the secretory ameloblasts. The esterases may be proteolytic enzymes that participate in the degradation of the matrix proteins....

  12. The Textile Form of Sound

    DEFF Research Database (Denmark)

    Bendixen, Cecilie

    Sound is a part of architecture, and sound is complex. Upon this, sound is invisible. How is it then possible to design visual objects that interact with the sound? This paper addresses the problem of how to get access to the complexity of sound and how to make textile material revealing the form...... goemetry by analysing the sound pattern at a specific spot. This analysis is done theoretically with algorithmic systems and practical with waves in water. The paper describes the experiments and the findings, and explains how an analysis of sound can be catched in a textile form....

  13. Effect of ethanol-wet-bonding technique on resin–enamel bonds

    Directory of Open Access Journals (Sweden)

    Muhammet Kerim Ayar

    2014-03-01

    Conclusion: The ethanol-wet-bonding technique may increase the bond strength of commercial adhesives to enamel. The chemical composition of the adhesives can affect the bond strength of adhesives when bonding to acid-etched enamel, using the ethanol-wet-bonding technique. Some adhesive systems used in the present study may simultaneously be applied to enamel and dentin using ethanol-wet-bonding. Furthermore, deploying ethanol-wet-bonding for the tested commercial adhesives to enamel can increase the adhesion abilities of these adhesives to enamel.

  14. Thermal Transformations of Iron Cations in the System Metal-Vitreous Enamel Coat. Moessbauer Spectroscopic Study

    International Nuclear Information System (INIS)

    Barcova, K.; Mashlan, M.; Zboril, R.; Hrabovska, K.

    2005-01-01

    Vitreous enameling on steel is carried out to provide a protective layer against chemical corrosion from the surrounding environment. The glass bonds with the steel to form a composite material. The Moessbauer spectroscopy was firstly applied to study the vitreous enameling in which the complex of processes, as diffusion of species, adhesion between the glass and the steel, galvanic reactions, plays an important role. The Moessbauer spectroscopy provides unique information about the Fe-phase structure of the vitreous enamel layer and that of the steel-enamel interface. Diffusion of iron from steel surface towards enamel layer and formation of a new Fe2+ phase was proved

  15. Determination of fracture toughness of human permanent and primary enamel using an indentation microfracture method.

    Science.gov (United States)

    Hayashi-Sakai, Sachiko; Sakai, Jun; Sakamoto, Makoto; Endo, Hideaki

    2012-09-01

    The purpose of the present study was to examine the fracture toughness and Vickers microhardness number of permanent and primary human enamel using the indentation microfracture method. Crack resistance and a parameter indirectly related to fracture toughness were measured in 48 enamel specimens from 16 permanent teeth and 12 enamel specimens obtained from six primary teeth. The Vickers microhardness number of the middle portion was greater than the upper portion in primary enamel. The fracture toughness was highest in the middle portion of permanent enamel, because fracture toughness greatly depends upon microstructure. These findings suggest that primary teeth are not miniature permanent teeth but have specific and characteristic mechanical properties.

  16. Comparison of fluoride uptake level by enamel from Iranian school brand and standard NaF mouthrinses

    Directory of Open Access Journals (Sweden)

    Gasem Ansari

    2009-03-01

    Full Text Available Background and aims. The use of fluoride mouthrinses has been proved to be one of the most effective ways to prevent tooth decay. A community based program using F+ rinse at school has also proved to be well-controlled and efficient. The aim of this investigation was to evaluate fluoride uptake level of a locally prepared NaF rinse used in Iran’s school program during 2005. Materials and methods. A total of 30 freshly extracted sound human premolars were collected and divided into two groups of 15. Each tooth then underwent two steps of sectioning; first the root was amputated from CEJ and then a longitudinal section was performed in bucco-lingual direction to provide two similar samples of the same tooth. A specific hemi-circular area on either of the experimental halves was treated by NaF rinse from USA or a locally prepared NaF used in school programs. Two subsequent biopsies were taken from each half using acid etch enamel biopsy technique. Fluoride and calcium content of the specimens were measured in order to evaluate fluoride uptake level and biopsy depth effect, respectively. Collected data were recorded in the forms provided and statistical analysis, mostly descriptive, was performed for comparison. Results. Based on the data collected, it appears that the use of F+ rinse would clearly improve enamel quality by a rise in fluoride concentration. Statistical analysis using a paired t-test and repeated measure method revealed that with 95% confidence fluoride concentration increases at both levels of biopsy with no statistically significant differences between the samples treated with two rinses. Conclusion. There seem to be reasonable potential for the clinical use of Iranian brand fluoride mouthrinse. There was no significant difference between the level of uptake from NaF from USA and the Iranian product in 2 layers of enamel biopsy.

  17. The CPP-ACP relieved enamel erosion from a carbonated soft beverage: an in vitro AFM and XRD study.

    Science.gov (United States)

    Wang, C P; Huang, S B; Liu, Y; Li, J Y; Yu, H Y

    2014-03-01

    To investigate the CPP-ACP's effect on enamel against carbonated beverage erosion and explore the potential mechanism. A total of 30 enamel samples were prepared from sound bovine incisors, divided into 3 groups. Samples in the control group were kept in artificial saliva. Specimens' surfaces were smeared with a CPP-ACP agent (Tooth Mousse, TM) for 3 min, rinsed with distilled water for 10s, merged into cola (Coca Cola, CC) for 4 intervals of 2 min, rinsed again for the TM+CC group. In the CC group, specimens were treated solely with cola for 4 intervals (2 min each). The cycles were applied at 0, 12, 24, 36, 48 and 60 h. The surface microhardness (SMH) alterations were measured using a microhardness tester, the surface profiles were analyzed using the atomic force microscope, and the surface crystalline amount (I%) and crystallinity (FWHM) were analyzed using X-ray diffractometer. The SMH were significantly decreased in CC group, showing the largest SMH alteration; the reduction of SMH in TM+CC group was lower than that in CC group, still larger than control. After cycles, the TM+CC group showed rougher surfaces than control, while the CC group had the roughest surfaces. The TM+CC had an I% higher than the CC, and lower than the control. The TM+CC group had a FWHM lower than CC, higher than control. CPP-ACP was able to relieve the erosion on enamel from carbonated beverage. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. An in vitro study of dental enamel wear by restorative materials using radiometric method

    International Nuclear Information System (INIS)

    Adachi, Lena Katekawa

    2000-01-01

    There is an increasing demand and interest to study the dental materials wear as well as about the abrasion effect on antagonistic teeth. Due to the fact that the existent restorative materials have no specifications about their abrasiveness, it is necessary the establishment of degrees of comparison among them to support clinical application. In this work, the radiometric method was applied to study the enamel wear caused by another enamel and by restorative materials (Ceramco II, Noritake and Finesse porcelains, Artglass and Targis). The dental enamel made radioactive by irradiation at the IEA-R1m nuclear research reactor under a thermal neutron flux was submitted to wear in a machine which allows sliding motion of an antagonistic surface in contact with this radioactive enamel. The enamel wear was evaluated by measuring beta activity of 32 P transferred to water from this irradiated tooth. Results obtained indicated that dental porcelains cause pronounced enamel wear when compared with that provoked by another enamel or by resin materials. Resin materials caused less enamel wear than another enamel. Vickers microhardness data obtained for antagonistic materials showed a correlation with the wear caused to the enamel. This study allowed to conclude that the radiometric method proposed can be used satisfactorily in the evaluation of enamel wear by restorative materials. This method presents advantages due to quick responses and ease of analyses There is (author)

  19. Quantitative assessment of the enamel machinability in tooth preparation with dental diamond burs.

    Science.gov (United States)

    Song, Xiao-Fei; Jin, Chen-Xin; Yin, Ling

    2015-01-01

    Enamel cutting using dental handpieces is a critical process in tooth preparation for dental restorations and treatment but the machinability of enamel is poorly understood. This paper reports on the first quantitative assessment of the enamel machinability using computer-assisted numerical control, high-speed data acquisition, and force sensing systems. The enamel machinability in terms of cutting forces, force ratio, cutting torque, cutting speed and specific cutting energy were characterized in relation to enamel surface orientation, specific material removal rate and diamond bur grit size. The results show that enamel surface orientation, specific material removal rate and diamond bur grit size critically affected the enamel cutting capability. Cutting buccal/lingual surfaces resulted in significantly higher tangential and normal forces, torques and specific energy (pmachinability for clinical dental practice. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Error in assessing the absorbed dose from the EPR signal from dental enamel

    International Nuclear Information System (INIS)

    Kleshchenko, E.D.; Kushnereva, K.K.

    1997-01-01

    Dose measurements from EPR signals from dental enamel were analyzed in a random sampling of 100 teeth extracted in liquidators of the Chernobyl accident aftermath and the EPR spectra of dental enamel of 80 intact teeth from children studied. The mean square deviation of enamel sensitivity to ionizing radiation in some teeth is approximately 0.3 of the mean sensitivity value. The variability of the nature EPR spectrum of dental enamel limits in principle the lower threshold of EPR-measured 60 mGy doses. When assessing the individual absorbed doses from the EPR signal from dental enamel without additional exposure it is necessary to bear in mind the extra error of approximately 6-% at a confidence probability P=0.95 caused by the variability of enamel sensitivity to radiation in some teeth. This additional error may be ruled out by graduated additional exposure of the examined enamel samples

  1. Sea otter dental enamel is highly resistant to chipping due to its microstructure.

    Science.gov (United States)

    Ziscovici, Charles; Lucas, Peter W; Constantino, Paul J; Bromage, Timothy G; van Casteren, Adam

    2014-10-01

    Dental enamel is prone to damage by chipping with large hard objects at forces that depend on chip size and enamel toughness. Experiments on modern human teeth have suggested that some ante-mortem chips on fossil hominin enamel were produced by bite forces near physiological maxima. Here, we show that equivalent chips in sea otter enamel require even higher forces than human enamel. Increased fracture resistance correlates with more intense enamel prism decussation, often seen also in some fossil hominins. It is possible therefore that enamel chips in such hominins may have formed at even greater forces than currently envisaged. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  2. Evaluation of the Esthetic Properties of Developmental Defects of Enamel: A Spectrophotometric Clinical Study

    Directory of Open Access Journals (Sweden)

    Fabrizio Guerra

    2015-01-01

    Full Text Available Objectives. Detailed clinical quantification of optical properties of developmental defect of enamel is possible with spectrophotometric evaluation. Developmental defects of enamel (DDE are daily encountered in clinical practice. DDE are an alteration in quality and quantity of the enamel, caused by disruption and/or damage to the enamel organ during amelogenesis. Methods. Several clinical indices have been developed to categorize enamel defects based on their nature, appearance, microscopic features, or cause. A sample of 39 permanent teeth presenting DDE on labial surface was examined using the DDE Modified Index and SpectroShade evaluation. The spectrophotometric approach quantifies L* (luminosity, a* (quantity of green-red, and b* (quantity of blue-yellow of different DDE. Conclusions. SpectroShade evaluation of the optical properties of the enamel defect enhances clinical understanding of severity and extent of the defect and characterizes the enamel alteration in terms of color discrepancy and surface characterization.

  3. Distinguishing between enamel fluorosis and other enamel defects in permanent teeth of children

    Directory of Open Access Journals (Sweden)

    Aira Sabokseir

    2016-02-01

    Full Text Available Background. The inconsistent prevalence of fluorosis for a given level of fluoride in drinking water suggests developmental defects of enamel (DDEs other than fluorosis were being misdiagnosed as fluorosis. The imprecise definition and subjective perception of fluorosis indices could result in misdiagnosis of dental fluorosis. This study was conducted to distinguish genuine fluorosis from fluorosis-resembling defects that could have adverse health-related events as a cause using Early Childhood Events Life-grid method (ECEL. Methods. A study was conducted on 400 9-year-old children from areas with high, optimal and low levels of fluoride in the drinking water of Fars province, Iran. Fluorosis cases were diagnosed on the standardized one view photographs of the anterior teeth using Dean’s and TF (Thylstrup and Fejerskov Indices by calibrated dentists. Agreements between examiners were tested. Early childhood health-related data collected retrospectively by ECEL method were matched with the position of enamel defects. Results. Using both Dean and TF indices three out of four dentists diagnosed that 31.3% (115 children had fluorosis, 58.0%, 29.1%, and 10.0% in high (2.12–2.85 ppm, optimal (0.62–1.22 ppm, and low (0.24–0.29 ppm fluoride areas respectively (p < 0.001. After matching health-related events in the 115 (31.3% of children diagnosed with fluorosis, 31 (8.4% of children had fluorosis which could be matched with their adverse health-related events. This suggests that what was diagnosed as fluorosis were non-fluoride related DDEs that resemble fluorosis. Discussion. The frequently used measures of fluorosis appear to overscore fluorosis. Use of ECEL method to consider health related events relevant to DDEs could help to differentiate between genuine fluorosis and fluorosis-resembling defects.

  4. Sign of the Cross (Signum Crucis): observation of an uncommon ictal manifestation of mesial temporal lobe epilepsy.

    Science.gov (United States)

    Lin, Katia; Marx, Catherine; Caboclo, Luis O S F; Centeno, Ricardo S; Sakamoto, Américo C; Yacubian, Elza M T

    2009-02-01

    The objective of the study was to describe the clinical characteristics and determine the lateralizing value of ictal Sign of the Cross (SC) as a complex hand automatism (CHA) in patients evaluated by video/EEG monitoring in a comprehensive epilepsy unit. We reviewed video/EEG data of 530 patients with epilepsy recorded in a tertiary epilepsy center from 2002 to 2008. Four patients were found to have manifested a CHA similar to the SC at least once during their complex partial seizures. All patients had unilateral right mesial temporal lobe epilepsy (TLE) refractory to medical treatment. The limbic system is often suggested as the critical site of religious experience. Moreover, it may be localized predominantly to the temporal regions of the right hemisphere. However, this rare and peculiar ictal manifestation may be related not only to the neural substrate and personality characteristics of TLE, but also to the general religious convictions of Brazilians.

  5. Interictal SPECT in the pre surgical evaluation in epileptic patients with normal MRI or bilateral mesial temporal sclerosis

    International Nuclear Information System (INIS)

    Marques, Lucia H.N.; Ferraz-Filho, Jose R.L.; Lins-Filho, Mario L.M.

    2009-01-01

    The aim of this study was to evaluate the sensitivity of interictal compared to ictal SPECT in the lateralization of the epileptogenic focus in refractory temporal lobe epilepsy (TLE) patients that present with normal magnetic resonance imaging (MRI) or bilateral mesial temporal sclerosis (MTS). Thirty patients with TLE, for whom MRI examinations were normal or who presented with bilateral MTS, were retrospectively studied. Using a confidence interval of 95% and a level of significance for p-value <0.05, an estimated agreement rate of 73% with a minimum agreement rate of 57% was calculated comparing interictal and ictal SPECTs. In conclusion the interictal SPECT is only useful when associated with the ictal SPECT and does not substitute it in the localization of epileptogenic areas in patients with normal MRI or bilateral MTS. (author)

  6. Four canals in the mesial root of a mandibular first molar. A case report under the operating microscope.

    Science.gov (United States)

    Kontakiotis, Evangelos G; Tzanetakis, Giorgos N

    2007-08-01

    In this era of microscope-assisted endodontics, finding variations in root canal system anatomy is not uncommon. Operating microscopes combined with careful clinical examination and radiographic interpretation can aid the clinician to successfully treat cases with such internal anatomy. The understanding of this view enables the possible location of additional canals in any tooth requiring endodontic treatment. The present clinical article demonstrates a rare anatomical complexity in the mesial root of a mandibular first molar. Four independent root canal orifices were found in this root by clinical detection with the aid of a dental operating microscope. This case shows that additional canals can be located in any root undergoing endodontic treatment and clinicians should always be aware of aberrant internal anatomy.

  7. Interictal SPECT in the pre surgical evaluation in epileptic patients with normal MRI or bilateral mesial temporal sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Lucia H.N. [Hospital de Base, Sao Jose do Rio Preto, SP (Brazil). Dept. de Neurologia. Centro Cirurgico de Epilepsia; Faculdade de Medicina de Sao Jose do Rio Preto (FAMERP), SP (Brazil); Ferraz-Filho, Jose R.L. [Hospital de Base, Sao Jose do Rio Preto, SP (Brazil); Lins-Filho, Mario L.M. [Hospital de Base, Sao Jose do Rio Preto, SP (Brazil). Dept. de Radiologia; Maciel, Marina G.; Yoshitake, Rafael; Filetti, Sarah V. [Faculdade de Medicina de Sao Jose do Rio Preto (FAMERP), SP (Brazil)

    2009-07-01

    The aim of this study was to evaluate the sensitivity of interictal compared to ictal SPECT in the lateralization of the epileptogenic focus in refractory temporal lobe epilepsy (TLE) patients that present with normal magnetic resonance imaging (MRI) or bilateral mesial temporal sclerosis (MTS). Thirty patients with TLE, for whom MRI examinations were normal or who presented with bilateral MTS, were retrospectively studied. Using a confidence interval of 95% and a level of significance for p-value <0.05, an estimated agreement rate of 73% with a minimum agreement rate of 57% was calculated comparing interictal and ictal SPECTs. In conclusion the interictal SPECT is only useful when associated with the ictal SPECT and does not substitute it in the localization of epileptogenic areas in patients with normal MRI or bilateral MTS. (author)

  8. Crossed cerebellar hyperperfusion on ictal Tc-99m HMPAO brain SPECT: clinical significance for differentiation of mesial or lateral temporal lobe epilepsy and related factors for development

    International Nuclear Information System (INIS)

    Park, Soon Ah; Sohn, Myung Hee; Lim, Seok Tae; Lee, Dong Soo; Lee, Sang Gun; Kim, Seok Ki; Jang, Myoung Jin; Chung, June Key; Lee, Myung Chul

    2000-01-01

    The aim of this study was to determine whether crossed cerebellar hyperperfusion (CCH) was helpful in discriminating mesial from lateral temporal lobe epilepsy (TLE) and what other factors were related in the development of CCH on ictal brain SPECT. We conducted retrospective analysis in 59 patients with TLE (M:41, F:18; 27.4±7.8 years old; mesial TLE: 51, lateral TLE: 8), which was confirmed by invasive EEG and surgical outcome (Engel class 1, 2). All the patients underwent ictal Tc-99m HMPAO brain SPECT and their injection time from ictal EEG onset on video EEG monitoring ranged from 11 sec to 75 sec (32.6±19.5 sec) in 39 patients. Multiple factors including age, TLE subtype (mesial TLE or lateral TLE), propatation pattern (hyperperfusion localized to temporal lobes, spread to adjacent lobes or contralateral hemisphere) and injection time were evaluated for their relationship with CCH using multiple logistic regression analysis CCH was observed in 18 among 59 patients. CCH developed in 29% (15/51) of mesial TLE patients and 38% (3/8) of lateral TLE patients. CCH was associated with propagation pattern; no CCH (0/13) in patients with hyperperfusion localized to temporal lobe, 30% (7/23) in patients with propagation to adjacent lobes, 48% (11/23) to contralateral hemisphere. Multiple logistic regression analysis revealed that propagation pattern (p=3D0.01) and age (p=3D0.02) were related to the development of CCH. Crossed cerebellar hyperperfusion in ictal brain SPECT did not help differentiate mesial from lateral remporal lobe epilepsy. Crossed cerebellar hyperperfusion was associated with propagation pattern of temporal lobe epilepsy and age.=20

  9. Crossed cerebellar hyperperfusion on ictal Tc-99m HMPAO brain SPECT: clinical significance for differentiation of mesial or lateral temporal lobe epilepsy and related factors for development

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soon Ah; Sohn, Myung Hee; Lim, Seok Tae [Chonbuk National Univ. School of Medicine, Chonju (Korea, Republic of); Lee, Dong Soo; Lee, Sang Gun; Kim, Seok Ki; Jang, Myoung Jin; Chung, June Key; Lee, Myung Chul [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

    2000-08-01

    The aim of this study was to determine whether crossed cerebellar hyperperfusion (CCH) was helpful in discriminating mesial from lateral temporal lobe epilepsy (TLE) and what other factors were related in the development of CCH on ictal brain SPECT. We conducted retrospective analysis in 59 patients with TLE (M:41, F:18; 27.4{+-}7.8 years old; mesial TLE: 51, lateral TLE: 8), which was confirmed by invasive EEG and surgical outcome (Engel class 1, 2). All the patients underwent ictal Tc-99m HMPAO brain SPECT and their injection time from ictal EEG onset on video EEG monitoring ranged from 11 sec to 75 sec (32.6{+-}19.5 sec) in 39 patients. Multiple factors including age, TLE subtype (mesial TLE or lateral TLE), propatation pattern (hyperperfusion localized to temporal lobes, spread to adjacent lobes or contralateral hemisphere) and injection time were evaluated for their relationship with CCH using multiple logistic regression analysis CCH was observed in 18 among 59 patients. CCH developed in 29% (15/51) of mesial TLE patients and 38% (3/8) of lateral TLE patients. CCH was associated with propagation pattern; no CCH (0/13) in patients with hyperperfusion localized to temporal lobe, 30% (7/23) in patients with propagation to adjacent lobes, 48% (11/23) to contralateral hemisphere. Multiple logistic regression analysis revealed that propagation pattern (p=3D0.01) and age (p=3D0.02) were related to the development of CCH. Crossed cerebellar hyperperfusion in ictal brain SPECT did not help differentiate mesial from lateral remporal lobe epilepsy. Crossed cerebellar hyperperfusion was associated with propagation pattern of temporal lobe epilepsy and age.

  10. Sound & The Society

    DEFF Research Database (Denmark)

    Schulze, Holger

    2014-01-01

    How are those sounds you hear right now socially constructed and evaluated, how are they architecturally conceptualized and how dependant on urban planning, industrial developments and political decisions are they really? How is your ability to hear intertwined with social interactions and their ...... and their professional design? And how is listening and sounding a deeply social activity – constructing our way of living together in cities as well as in apartment houses? A radio feature with Nina Backmann, Jochen Bonz, Stefan Krebs, Esther Schelander & Holger Schulze......How are those sounds you hear right now socially constructed and evaluated, how are they architecturally conceptualized and how dependant on urban planning, industrial developments and political decisions are they really? How is your ability to hear intertwined with social interactions...

  11. Urban Sound Interfaces

    DEFF Research Database (Denmark)

    Breinbjerg, Morten

    2012-01-01

    This paper draws on the theories of Michel de Certeau and Gaston Bachelard to discuss how media architecture, in the form of urban sound interfaces, can help us perceive the complexity of the spaces we inhabit, by exploring the history and the narratives of the places in which we live. In this pa......This paper draws on the theories of Michel de Certeau and Gaston Bachelard to discuss how media architecture, in the form of urban sound interfaces, can help us perceive the complexity of the spaces we inhabit, by exploring the history and the narratives of the places in which we live....... In this paper, three sound works are discussed in relation to the iPod, which is considered as a more private way to explore urban environments, and as a way to control the individual perception of urban spaces....

  12. Predicting outdoor sound

    CERN Document Server

    Attenborough, Keith; Horoshenkov, Kirill

    2014-01-01

    1. Introduction  2. The Propagation of Sound Near Ground Surfaces in a Homogeneous Medium  3. Predicting the Acoustical Properties of Outdoor Ground Surfaces  4. Measurements of the Acoustical Properties of Ground Surfaces and Comparisons with Models  5. Predicting Effects of Source Characteristics on Outdoor Sound  6. Predictions, Approximations and Empirical Results for Ground Effect Excluding Meteorological Effects  7. Influence of Source Motion on Ground Effect and Diffraction  8. Predicting Effects of Mixed Impedance Ground  9. Predicting the Performance of Outdoor Noise Barriers  10. Predicting Effects of Vegetation, Trees and Turbulence  11. Analytical Approximations including Ground Effect, Refraction and Turbulence  12. Prediction Schemes  13. Predicting Sound in an Urban Environment.

  13. Facial paresis in patients with mesial temporal sclerosis: clinical and quantitative MRI-based evidence of widespread disease.

    Science.gov (United States)

    Lin, Katia; Carrete, Henrique; Lin, Jaime; de Oliveira, Pedro Alessandro Leite; Caboclo, Luis Otávio Sales Ferreira; Sakamoto, Américo Ceiki; Yacubian, Elza Márcia Targas

    2007-08-01

    To assess the frequency and significance of facial paresis (FP) in a well-defined cohort of mesial temporal lobe epilepsy (MTLE) patients. One hundred consecutive patients with MRI findings consistent with mesial temporal sclerosis (MTS) and concordant electroclinical data underwent facial motor examination at rest, with voluntary expression, and with spontaneous smiling. Hippocampal, amygdaloid, and temporopolar (TP) volumetric measures were acquired. Thirty healthy subjects, matched according to age and sex, were taken as controls. Central-type FP was found in 46 patients. In 41 (89%) of 46, it was visualized at rest, with voluntary and emotional expression characterizing true facial motor paresis. In 33 (72%) of 46 patients, FP was contralateral to the side of MTS. By using a 2-SD cutoff from the mean of normal controls, we found reduction in TP volume ipsilateral to MTS in 61% of patients with FP and in 33% of those without (p = 0.01). Febrile seizures as initial precipitating injury (IPI) were observed in 34% of the patients and were classified as complex in 12 (26%) of 46 of those with FP and in five (9%) of 54 of those without (p = 0.02). The presence of FP was significantly associated with a shorter latent period and younger age at onset of habitual seizures, in particular, with secondarily generalized tonic-clonic seizures. Facial paresis is a reliable lateralizing sign in MTLE and was associated with history of complex febrile seizures as IPI, younger age at onset of disease, and atrophy of temporal pole ipsilateral to MTS, indicating more widespread disease.

  14. Relationship between remnant hippocampus and amygdala and memory outcomes after stereotactic surgery for mesial temporal lobe epilepsy.

    Science.gov (United States)

    Malikova, Hana; Kramska, Lenka; Vojtech, Zdenek; Sroubek, Jan; Lukavsky, Jiri; Liscak, Roman

    2015-01-01

    Mesial temporal structures play an important role in human memory. In mesial temporal lobe epilepsy (MTLE), seizure activity is generated from the same structures. Surgery is the definitive treatment for medically intractable MTLE. In addition to standard temporal lobe microsurgical resection, stereotactic radiofrequency amygdalohippocampectomy (SAHE) is used as an alternative MTLE treatment. While memory impairments after standard epilepsy surgery are well known, it has been shown that memory decline is not a feature of SAHE. The aim of the present study was to correlate the volume of the remnant hippocampus and amygdala in patients treated by SAHE with changes in memory parameters. Thirty-seven MTLE patients treated by SAHE (ten right, 27 left) were included. Patients underwent magnetic resonance imaging examinations including hippocampal and amygdalar volumetry and neuropsychological evaluation preoperatively and 1 year after surgery. Using Spearman correlation analyses, larger left-sided hippocampal reductions were associated with lower verbal memory performance (ρ=-0.46; P=0.02). On the contrary, improvement of global memory quotient (MQ) was positively correlated with larger right-sided hippocampal reduction (ρ=0.66; P=0.04). Similarly, positive correlations between the extent of right amygdalar reduction and verbal MQ (ρ=0.74; P=0.02) and global MQ change (ρ=0.69; P=0.03) were found. Thus, larger right hippocampal and amygdalar reduction was associated with higher global and verbal MQ change after SAHE. Larger left-sided hippocampal reductions were associated with lower verbal memory performance. This finding is in accordance with the material-specific model of human memory, which states that the dominant hemisphere is specialized for the learning and recall of verbal information. We hypothesize that larger right-sided ablations enable the left temporal lobe to support memory more effectively, perhaps as a consequence of epileptiform discharges spreading

  15. The role of histopathologic subtype in the setting of hippocampal sclerosis-associated mesial temporal lobe epilepsy.

    Science.gov (United States)

    Gales, Jordan M; Jehi, Lara; Nowacki, Amy; Prayson, Richard A

    2017-05-01

    Hippocampal sclerosis (HS) and focal cortical dysplasia (FCD) are among the most common neuropathological findings in those undergoing surgery for refractory mesial temporal lobe epilepsy. Existing data regarding differences among the most recent International League Against Epilepsy (ILAE) HS subtypes remain limited. This study sought to characterize the roles of HS subtype and coexistent FCD. Epilepsy surgery pathologic specimens in 307 cases of temporal lobe epilepsy with HS were reviewed (mean age±SD, 37±15years; 56% women). HS and coexistent FCD were classified according to ILAE guidelines. Medical records were reviewed for data on seizure recurrence and seizure burden (clinical follow-up mean duration ± SD, 5±4years). Cases of typical HS (ILAE type I) predominated (ILAE type Ia: 41%, Ib: 47%, II: 11%, and III: 0.7%]. The HS subtypes shared similar demographic and etiologic characteristics, as well as associated pathology and postoperative seizure outcomes. Individuals with type Ib HS were more likely to remain seizure free at long-term follow-up when compared with other subtypes, and they had a later age of seizure onset. Two hundred forty-three cases (79%) demonstrated FCD within the adjacent temporal lobe. Its presence was associated with a significantly decreased risk of seizure recurrence (P=.02). When present, FCD was predominantly type I (98%). HS subtype does not appear to affect epilepsy surgery outcomes despite some clinical differences between the subgroups. FCD is often observed in association with HS in mesial temporal lobe epilepsy; the finding of FCD was associated with better postoperative outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Confiabilidade de medidas volumétricas de estruturas temporais mesiais Reliability of mesial temporal lobe volumetric measures

    Directory of Open Access Journals (Sweden)

    Renato L. Marchetti

    2002-06-01

    Full Text Available MOTIVO DO ESTUDO: O desenvolvimento de técnicas confiáveis para a realização de medidas volumétricas de estruturas temporais mesiais (amígdala, hipocampo e giro para-hipocampal em exames de ressonância magnética (RM pode fornecer dados para o estudo de vários transtornos neuropsiquiátricos, particularmente epilepsia do lobo temporal, doença de Alzheimer e esquizofrenia. MÉTODO: Investigamos essas técnicas realizando estudo de confiabilidade intra-observador (IO e entre-observador (EO, envolvendo controles normais, pacientes com epilepsia e pacientes com doença de Alzheimer, através do coeficiente de correlação intra-classe (CCI. RESULTADOS: A confiabilidade IO para as estruturas analisadas variou de 0,93 a 0,99 (pRATIONALE: The development of reliable techniques for volumetric measurement of mesial temporal structures (amygdala, hypocampus and parahypocampal gyrus on magnetic resonance imaging (MRI can provide data for the study of neuropsychiatric disorders, mainly temporal lobe epilepsy, Alzheimer´s disease and schizophrenia. METHOD: We investigated these techniques performing intraobserver and interobserver reliability study concerning normal controls, epilepsy and Alzheimer's disease patients using the intra-class correlation coefficient. RESULTS: Intra-observer reliability of evaluated structures ranged from 0.93 to 0.99 (p<0.001. Inter-observer reliability ranged from 0.70 to 0.95 (p <= 0.001. CONCLUSION: The results suggest that the technique of MRI morphometry of mesial temporal regions can be considered a reliable tool which may help in the investigation of neuropsychiatric disorders, since used by adequately trained clinicians and researchers.

  17. An evaluation of canal curvature at the apical one third in type II mesial canals of mandibular molars

    Directory of Open Access Journals (Sweden)

    Hye-Rim Yun

    2012-05-01

    Full Text Available Objectives The purpose of this study was to evaluate the buccolingual curvature at the apical one third in type II mesial canals of mandibular molars using the radius and angle of curvature. Materials and Methods Total 100 mandibular molars were selected. Following an endodontic access in the teeth, their distal roots were removed. #15 H- or K-files (Dentsply Maillefer were inserted into the mesiobuccal and mesiolingual canals of the teeth. Radiographs of the teeth were taken for the proximal view. Among them, type II canals were selected and divided into two subgroups, IIa and IIb. In type IIa, two separate canals merged into one canal before reaching the apex and in type IIb, two separate canals merged into one canal within the apical foramen. The radius and angle of curvature of specimens were examined. Results In type II, mean radius of curvature in mesiolingual and mesiobuccal canals were 2.82 mm and 3.58 mm, respectively. The radius of the curvature of mesiolingual canals were significantly smaller than that of mesiobuccal canals in type II, and especially in type IIa. However, there were no statistically significant differences in radius of curvature between mesiobuccal and mesiolingual canals in type IIb and there were no significant differences in angle of curvature between type IIa and IIb. Conclusion In this study, type II mesial canals of mandibular molars showed severe curvature in the proximal view. Especially, mesiolingual canals of type IIa had more abrupt curvature than mesiobuccal canals at the apical one third.

  18. Application of T2 relaxometry in lateralization and localization of mesial temporal lobe epilepsy and corresponding comparison with MR volumetry.

    Science.gov (United States)

    Chen, Hui; Yu, Guilian; Wang, Jiangtao; Li, Feng; Li, Guangming

    2016-09-01

    Magnetic resonance (MR) volumetry is insensitive to subtle mesial temporal sclerosis (MTS), while T2 relaxometry is potential useful in detecting MTS, especially MTS in early course. To explore and compare the feasibility of T2 relaxometry and MR volumetry in evaluation of mesial temporal lobe epilepsy (MTLE) and lateralization of the epileptogenic zone, so as to optimize and enhance lesion depiction. For the 17 unilateral MTLE patients and 14 normal participants, the hippocampus and amygdala were contoured on axial T2-weighted (T2W) images and then co-registered onto T2 relaxation maps. Abnormal is defined as an elevated asymmetric ratio of larger than 2 SD. Visual and quantitative volumetric assessment were combined as outcomes of MR volumetry to distinguish MR-positive and MR-negative lesions. Operative and pathological findings were used as gold standard. T2 values of lesions were significantly elevated. In lateralizing the epileptogenic zones, T2 relaxometry yielded an overall accuracy of 94.1% (sensitivity 92.6%, specificity 100%), and MR volumetry yielded an overall accuracy of 82.4% (sensitivity 88.9%, specificity 57.1%), meaning a better performance of T2 relaxometry (P volumetry. MR volumetry wrongly discerned three normal regions as MTS, while one MR-negative sclerotic hippocampus was detected by T2 relaxometry. T2 relaxometry is feasible in non-invasive lateralization of epileptogenic zone, and more advantaged than MR volumetry in detecting MR-negative lesions, facilitating prompt diagnosis and longitudinal disease monitoring. © The Foundation Acta Radiologica 2015.

  19. Sound & The Senses

    DEFF Research Database (Denmark)

    Schulze, Holger

    2012-01-01

    How are those sounds you hear right now technically generated and post-produced, how are they aesthetically conceptualized and how culturally dependant are they really? How is your ability to hear intertwined with all the other senses and their cultural, biographical and technological constructio...... over time? And how is listening and sounding a deeply social activity – constructing our way of living together in cities as well as in apartment houses? A radio feature with Jonathan Sterne, AGF a.k.a Antye Greie, Jens Gerrit Papenburg & Holger Schulze....

  20. Handbook for sound engineers

    CERN Document Server

    Ballou, Glen

    2013-01-01

    Handbook for Sound Engineers is the most comprehensive reference available for audio engineers. All audio topics are explored: if you work on anything related to audio you should not be without this book! The 4th edition of this trusted reference has been updated to reflect changes in the industry since the publication of the 3rd edition in 2002 -- including new technologies like software-based recording systems such as Pro Tools and Sound Forge; digital recording using MP3, wave files and others; mobile audio devices such as iPods and MP3 players. Over 40 topic

  1. Sound for digital video

    CERN Document Server

    Holman, Tomlinson

    2013-01-01

    Achieve professional quality sound on a limited budget! Harness all new, Hollywood style audio techniques to bring your independent film and video productions to the next level.In Sound for Digital Video, Second Edition industry experts Tomlinson Holman and Arthur Baum give you the tools and knowledge to apply recent advances in audio capture, video recording, editing workflow, and mixing to your own film or video with stunning results. This fresh edition is chockfull of techniques, tricks, and workflow secrets that you can apply to your own projects from preproduction

  2. Beacons of Sound

    DEFF Research Database (Denmark)

    Knakkergaard, Martin

    2018-01-01

    The chapter discusses expectations and imaginations vis-à-vis the concert hall of the twenty-first century. It outlines some of the central historical implications of western culture’s haven for sounding music. Based on the author’s study of the Icelandic concert-house Harpa, the chapter considers...... how these implications, together with the prime mover’s visions, have been transformed as private investors and politicians took over. The chapter furthermore investigates the objectives regarding musical sound and the far-reaching demands concerning acoustics that modern concert halls are required...

  3. Neuroplasticity beyond sounds

    DEFF Research Database (Denmark)

    Reybrouck, Mark; Brattico, Elvira

    2015-01-01

    Capitalizing from neuroscience knowledge on how individuals are affected by the sound environment, we propose to adopt a cybernetic and ecological point of view on the musical aesthetic experience, which includes subprocesses, such as feature extraction and integration, early affective reactions...... and motor actions, style mastering and conceptualization, emotion and proprioception, evaluation and preference. In this perspective, the role of the listener/composer/performer is seen as that of an active "agent" coping in highly individual ways with the sounds. The findings concerning the neural...

  4. Eliciting Sound Memories.

    Science.gov (United States)

    Harris, Anna

    2015-11-01

    Sensory experiences are often considered triggers of memory, most famously a little French cake dipped in lime blossom tea. Sense memory can also be evoked in public history research through techniques of elicitation. In this article I reflect on different social science methods for eliciting sound memories such as the use of sonic prompts, emplaced interviewing, and sound walks. I include examples from my research on medical listening. The article considers the relevance of this work for the conduct of oral histories, arguing that such methods "break the frame," allowing room for collaborative research connections and insights into the otherwise unarticulatable.

  5. SoleSound

    DEFF Research Database (Denmark)

    Zanotto, Damiano; Turchet, Luca; Boggs, Emily Marie

    2014-01-01

    This paper introduces the design of SoleSound, a wearable system designed to deliver ecological, audio-tactile, underfoot feedback. The device, which primarily targets clinical applications, uses an audio-tactile footstep synthesis engine informed by the readings of pressure and inertial sensors...... embedded in the footwear to integrate enhanced feedback modalities into the authors' previously developed instrumented footwear. The synthesis models currently implemented in the SoleSound simulate different ground surface interactions. Unlike similar devices, the system presented here is fully portable...

  6. Shear bond strength of hydrophilic adhesive systems to enamel.

    Science.gov (United States)

    Hara, A T; Amaral, C M; Pimenta, L A; Sinhoreti, M A

    1999-08-01

    To compare the enamel shear bond strength of four hydrophilic adhesive systems: one multiple-bottle (Scotchbond Multi-Purpose Plus), two one-bottle (Stae, Single Bond) and one self-etching (Etch & Prime). 120 bovine incisor teeth were obtained, embedded in polyester resin, polished to 600 grit to form standardized enamel surfaces, and randomly assigned to four groups (n = 30). Each adhesive system was used on enamel according to the manufacturer's instructions, and resin-based composite (Z100) cylinders with 3 mm diameter and 5 mm height were bonded. Specimens were stored in humid environment for 1 week, and bond strength was determined using a universal testing machine, at a crosshead speed of 0.5 mm/minute. The mean shear bond strength values (MPa +/- SD) were: Single Bond: 24.28 +/- 5.27 (a); Scotchbond Multi-Purpose Plus: 21.18 +/- 4.35 (ab); Stae: 19.56 +/- 4.71 (b); Etch & Prime 3.0: 15.13 +/- 4.92 (c). ANOVA revealed significant difference in means (P < 0.01) and Tukey's test showed the statistical differences that are expressed by different letters for each group. It could be concluded that the self-etching adhesive system did not provide as good a bond to enamel surface, as did the one- and multiple-bottle systems.

  7. Effect of Galla chinensis on enhancing remineralization of enamel crystals

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Lei; Huang Shengbin [State Key Laboratory of Oral Disease, Sichuan University, Chengdu (China); Li Jiyao; Zhou Xuedong, E-mail: stonedentist@yahoo.c [West China College of Stomatology, Sichuan University, Chengdu (China)

    2009-06-15

    The aim of this scanning electron microscopy (SEM) study was to investigate the effect of chemical compounds of Galla chinensis (GCE, gallic acid) on the remineralization of enamel crystals in vitro. Bovine enamel blocks with an in vitro produced initial lesion were used. The lesions were subjected to a pH-cycling regime for 12 days. Each daily cycle included 4 x 1 min applications with one of six treatments: group A: 1000 ppm F aq. (as NaF, positive control); group B: deionized water (DDW, negative control); group C: 4000 ppm crude aqueous extract of GCE; group D: 4000 ppm gallic acid; group E: 4000 ppm GCE with 1000 ppm F; group F: 4000 ppm gallic acid with 1000 ppm F. The surface and vertical section of the enamel lesions were analyzed by SEM. The results indicated that the chemical compounds of G. chinensis could regulate the de-/remineralization balance through influencing the morphology and structure of enamel crystals, and the mechanisms seem to be different for GCE and gallic acid.

  8. Effect of Galla chinensis on enhancing remineralization of enamel crystals

    International Nuclear Information System (INIS)

    Cheng Lei; Huang Shengbin; Li Jiyao; Zhou Xuedong

    2009-01-01

    The aim of this scanning electron microscopy (SEM) study was to investigate the effect of chemical compounds of Galla chinensis (GCE, gallic acid) on the remineralization of enamel crystals in vitro. Bovine enamel blocks with an in vitro produced initial lesion were used. The lesions were subjected to a pH-cycling regime for 12 days. Each daily cycle included 4 x 1 min applications with one of six treatments: group A: 1000 ppm F aq. (as NaF, positive control); group B: deionized water (DDW, negative control); group C: 4000 ppm crude aqueous extract of GCE; group D: 4000 ppm gallic acid; group E: 4000 ppm GCE with 1000 ppm F; group F: 4000 ppm gallic acid with 1000 ppm F. The surface and vertical section of the enamel lesions were analyzed by SEM. The results indicated that the chemical compounds of G. chinensis could regulate the de-/remineralization balance through influencing the morphology and structure of enamel crystals, and the mechanisms seem to be different for GCE and gallic acid.

  9. The remineralisation of enamel: a review of the literature.

    Science.gov (United States)

    Li, Xiaoke; Wang, Jinfang; Joiner, Andrew; Chang, Jiang

    2014-06-01

    The purpose of this paper is to review current knowledge and technologies for tooth remineralisation. The literature was searched using the "Scopus" and "Web of Knowledge" database from the year 1971, with principal key words of *miner*, teeth and enamel. Language was restricted to English. Original studies and reviews were included. Conference papers and posters were excluded. The importance of oral health for patients and consumers has seen a steady increase in the number of tooth remineralisation agents, products and procedures over recent years. Concomitantly, there has been continued publication of both in vivo and in vitro tooth remineralisation and demineralisation studies. It is clear that fluoride treatments are generally effective in helping to protect the dental enamel from demineralisation and enhancing remineralisation. Continued efforts to increase the efficacy of fluoride have been made, in particular, by the addition of calcium salts or calcium containing materials to oral care products which may enhance the delivery and retention of fluoride into the oral cavity. In addition, the calcium salts or materials may act as additional sources of calcium to promote enamel remineralisation or reduce demineralisation processes. Inspired by the concept of bioactive materials for bone repair and regeneration, bioglass and in particular calcium silicate type materials show potential for enamel health benefits and is a growing area of research. © 2014 Elsevier Ltd. All rights reserved.

  10. Quantitative evaluation of the enamel caries which were treated with ...

    African Journals Online (AJOL)

    Objectives: The aim of this in vivo study was to quantitatively evaluate the remineralization of the enamel caries on smooth and occlusal surfaces using DIAGNOdent, after daily application of casein phosphopeptide‑amorphous calcium fluoride phosphate (CPP‑ACFP). Materials and Methods: Thirty volunteers, aged 18–30 ...

  11. Human and bovine enamel erosion under 'single-drink' conditions

    NARCIS (Netherlands)

    White, Andrew J.; Yorath, Celyn; ten Hengel, Valerie; Leary, Sam D.; Huysmans, Marie-Charlotte D. N. J. M.; Barbour, Michele E.

    2010-01-01

    Tooth-surface pH is lowered, during drinking, to a value close to the pH of the drink itself. After the drink is swallowed, the pH rises to baseline values but this process can take several minutes. Few techniques can quantify enamel erosion at timescales representative of single drinks. The

  12. Argon laser induced changes to the carbonate content of enamel

    International Nuclear Information System (INIS)

    Ziglo, M.J.; Nelson, A.E.; Heo, G.; Major, P.W.

    2009-01-01

    Argon laser irradiation can be used to cure orthodontic brackets onto teeth in significantly less time than conventional curing lights. In addition, it has been shown that the argon laser seems to impart a demineralization resistance to the enamel. The purpose of this study was to use surface science techniques to ascertain if this demineralization resistance is possibly a result of a decrease in the carbonate content of enamel. Eleven mandibular third molars previously scheduled for extraction were collected and used in the present study. The teeth were sectioned in two and randomly assigned to either the argon laser (457-502 nm; 250 mW cm -2 ) or the control (no treatment) group. The sections assigned to the argon laser group were cured for 10 s and analyzed. To exaggerate any potential changes the experimental sections were then exposed to a further 110 s of argon laser irradiation. Surface analysis was performed using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results showed no statistically significant change in the carbonate content of enamel after argon laser irradiation (p > 0.05). Thus, it is suggested that any demineralization resistance imparted to the enamel surface by argon laser irradiation is not due to alterations in carbonate content.

  13. Argon laser induced changes to the carbonate content of enamel

    Energy Technology Data Exchange (ETDEWEB)

    Ziglo, M.J. [Orthodontic Graduate Program, Faculty of Medicine and Dentistry, University of Alberta, Private Practice, Regina, Saskatchewan (Canada); Nelson, A.E., E-mail: aenelson@dow.com [Department of Chemical and Materials Engineering, Faculty of Engineering, University of Alberta (Canada); Heo, G.; Major, P.W. [Orthodontic Graduate Program, Faculty of Medicine and Dentistry, University of Alberta (Canada)

    2009-05-15

    Argon laser irradiation can be used to cure orthodontic brackets onto teeth in significantly less time than conventional curing lights. In addition, it has been shown that the argon laser seems to impart a demineralization resistance to the enamel. The purpose of this study was to use surface science techniques to ascertain if this demineralization resistance is possibly a result of a decrease in the carbonate content of enamel. Eleven mandibular third molars previously scheduled for extraction were collected and used in the present study. The teeth were sectioned in two and randomly assigned to either the argon laser (457-502 nm; 250 mW cm{sup -2}) or the control (no treatment) group. The sections assigned to the argon laser group were cured for 10 s and analyzed. To exaggerate any potential changes the experimental sections were then exposed to a further 110 s of argon laser irradiation. Surface analysis was performed using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results showed no statistically significant change in the carbonate content of enamel after argon laser irradiation (p > 0.05). Thus, it is suggested that any demineralization resistance imparted to the enamel surface by argon laser irradiation is not due to alterations in carbonate content.

  14. Argon laser induced changes to the carbonate content of enamel

    Science.gov (United States)

    Ziglo, M. J.; Nelson, A. E.; Heo, G.; Major, P. W.

    2009-05-01

    Argon laser irradiation can be used to cure orthodontic brackets onto teeth in significantly less time than conventional curing lights. In addition, it has been shown that the argon laser seems to impart a demineralization resistance to the enamel. The purpose of this study was to use surface science techniques to ascertain if this demineralization resistance is possibly a result of a decrease in the carbonate content of enamel. Eleven mandibular third molars previously scheduled for extraction were collected and used in the present study. The teeth were sectioned in two and randomly assigned to either the argon laser (457-502 nm; 250 mW cm -2) or the control (no treatment) group. The sections assigned to the argon laser group were cured for 10 s and analyzed. To exaggerate any potential changes the experimental sections were then exposed to a further 110 s of argon laser irradiation. Surface analysis was performed using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results showed no statistically significant change in the carbonate content of enamel after argon laser irradiation ( p > 0.05). Thus, it is suggested that any demineralization resistance imparted to the enamel surface by argon laser irradiation is not due to alterations in carbonate content.

  15. Diffusion of calcium and fluride ions in bovine enamel

    NARCIS (Netherlands)

    Flim, Gerrit Jan

    1976-01-01

    This thesis deals with the diffusion of calcium and fluoride ions in bovine enamel, Special attention was given to the mechanism of this diffusion, The experiments were carried out with radioactive labeled ions. The information obtained is relevant with respect to de- and remineralization processes

  16. Elevated fluoride products enhance remineralization of advanced enamel lesions

    NARCIS (Netherlands)

    ten Cate, J.M.; Buijs, M.J.; Chaussain Miller, C.; Exterkate, R.A.M.

    2008-01-01

    Caries prevention might benefit from the use of toothpastes containing over 1500 ppm F. With few clinical studies available, the aim of this pH-cycling study was to investigate the dose response between 0 and 5000 ppm F of de- and remineralization of advanced (> 150 µm) enamel lesions. Treatments

  17. Contact fatigue of human enamel: Experiments, mechanisms and modeling.

    Science.gov (United States)

    Gao, S S; An, B B; Yahyazadehfar, M; Zhang, D; Arola, D D

    2016-07-01

    Cyclic contact between natural tooth structure and engineered ceramics is increasingly common. Fatigue of the enamel due to cyclic contact is rarely considered. The objectives of this investigation were to evaluate the fatigue behavior of human enamel by cyclic contact, and to assess the extent of damage over clinically relevant conditions. Cyclic contact experiments were conducted using the crowns of caries-free molars obtained from young donors. The cuspal locations were polished flat and subjected to cyclic contact with a spherical indenter of alumina at 2Hz. The progression of damage was monitored through the evolution in contact displacement, changes in the contact hysteresis and characteristics of the fracture pattern. The contact fatigue life diagram exhibited a decrease in cycles to failure with increasing cyclic load magnitude. Two distinct trends were identified, which corresponded to the development and propagation of a combination of cylindrical and radial cracks. Under contact loads of less than 400N, enamel rod decussation resisted the growth of subsurface cracks. However, at greater loads the damage progressed rapidly and accelerated fatigue failure. Overall, cyclic contact between ceramic appliances and natural tooth structure causes fatigue of the enamel. The extent of damage is dependent on the magnitude of cyclic stress and the ability of the decussation to arrest the fatigue damage. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Micro-indentation fracture behavior of human enamel.

    Science.gov (United States)

    Padmanabhan, Sanosh Kunjalukkal; Balakrishnan, Avinash; Chu, Min-Cheol; Kim, Taik Nam; Cho, Seong Jai

    2010-01-01

    The purpose of this study was to determine the crack resistance behavior (K(R)) of human enamel in relation to its microstructure. Human molar teeth were precision cut, polished and tested using Vickers micro-indentation at different loads ranging from 0.98 to 9.8 N. Five indentation load levels were considered, 20 indentation cracks for each load level were introduced on the surface of the test specimen (10 indentations per tooth) and their variability was evaluated using Weibull statistics and an empirical model. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to analyze the crack morphology and propagation mechanisms involved. The results showed that enamel exhibited increasing cracking resistance (K(R)) with increasing load. It was found that the crack propagation mainly depended on the location and the microstructure it encountered. SEM showed the formation of crack bridges and crack deflection near the indentation crack tip. The crack mode was of Palmqvist type even at larger loads of 9.8 N. This was mainly attributed to the large process zone created by the interwoven lamellar rod like microstructure exhibited by the enamel surface. This study shows that there are still considerable prospects for improving dental ceramics and for mimicking the enamel structure developed by nature.

  19. HeNe-laser light scattering by human dental enamel

    NARCIS (Netherlands)

    Zijp, [No Value; tenBosch, JJ; Groenhuis, RAJ

    1995-01-01

    Knowledge of the optical properties of tooth enamel and an understanding of the origin of these properties are necessary for the development of new optical methods for caries diagnosis and the measurement of tooth color. We measured the scattering intensity functions for HeNe-laser light of 80- to

  20. Composition of enamel pellicle from dental erosion patients.

    Science.gov (United States)

    Carpenter, G; Cotroneo, E; Moazzez, R; Rojas-Serrano, M; Donaldson, N; Austin, R; Zaidel, L; Bartlett, D; Proctor, G

    2014-01-01

    Oral health is dependent upon a thin mobile film of saliva on soft and hard tissues. Salivary proteins adhere to teeth to form the acquired enamel pellicle which is believed to protect teeth from acid erosion. This study investigated whether patients suffering diet-induced dental erosion had altered enamel pellicles. Thirty patients suffering erosion were compared to healthy age-matched controls. Subjects wore a maxillary splint holding hydroxyapatite and human enamel blocks for 1 h. The acquired enamel pellicle was removed from the blocks and compared to the natural incisor pellicle. Basic Erosive Wear Examination scores confirmed that dental erosion was present in erosion patients and absent from healthy age-matched controls. Erosion patients had half the amount of proteins (BCA assay) within the acquired pellicle forming on splint blocks compared to normal controls (p erosion patients (p erosion patients and healthy controls. In summary, the formation of new acquired pellicles on surfaces was reduced in erosion patients, which may explain their greater susceptibility to acid erosion of teeth. © 2014 S. Karger AG, Basel.

  1. Spectrally enhanced image resolution of tooth enamel surfaces

    Science.gov (United States)

    Zhang, Liang; Nelson, Leonard Y.; Berg, Joel H.; Seibel, Eric J.

    2012-01-01

    Short-wavelength 405 nm laser illumination of surface dental enamel using an ultrathin scanning fiber endoscope (SFE) produced enhanced detail of dental topography. The surfaces of human extracted teeth and artificial erosions were imaged with 405 nm, 444 nm, 532 nm, or 635 nm illumination lasers. The obtained images were then processed offline to compensate for any differences in the illumination beam diameters between the different lasers. Scattering and absorption coefficients for a Monte Carlo model of light propagation in dental enamel for 405 nm were scaled from published data at 532 nm and 633 nm. The value of the scattering coefficient used in the model was scaled from the coefficients at 532 nm and 633 nm by the inverse third power of wavelength. Simulations showed that the penetration depth of short-wavelength illumination is localized close to the enamel surface, while long-wavelength illumination travels much further and is backscattered from greater depths. Therefore, images obtained using short wavelength laser are not contaminated by the superposition of light reflected from enamel tissue at greater depths. Hence, the SFE with short-wavelength illumination may make it possible to visualize surface manifestations of phenomena such as demineralization, thus better aiding the clinician in the detection of early caries.

  2. The aesthetic and functional properties of enamel coatings on steel

    International Nuclear Information System (INIS)

    Scrinzi, E.; Rossi, S.

    2010-01-01

    In this work, the aesthetic and functional properties of enamelled steel panels were investigated. Enamelling is one of the oldest techniques to protect metallic substrates from corrosive phenomena and to improve the aesthetic aspects. This kind of coating is still up-to-date because of its durability, the possibility of creating different aesthetic effects and the eco-sustainability of the production process. Therefore, these kinds of coatings present a great potential in the field of product design. In this work, the durability and the change in the surface properties of different types of enamels are investigated. Chemical resistance, abrasion resistance and ultraviolet radiation (UV) exposure resistance were studied. To determine the chemical resistance, the samples were immersed in acid and basic solutions. Gloss and colour changes were measured. The falling abrasive test was used to evaluate the abrasion resistance: gloss changes were measured to determine the loss of aesthetic properties, and electrochemical impedance spectroscopy was used to evaluate the loss of protective properties. Gloss and colour changes were measured after 1000 h of UV exposure. Optical microscopy and environmental scanning electron microscopy were used to study the morphology of the damage and correlate it to the gloss and colour changes. All the samples presented good resistance in acid solution and good UV exposure resistance. For the other tests the results varied and were correlated to the characteristics of the enamels in terms of composition, thickness, surface roughness and application technique.

  3. Characterization of glazes, enamels and oxides by XRF

    International Nuclear Information System (INIS)

    Mbarek, Iheb

    2009-01-01

    The purpose of this work is to control the technique of X-ray fluorescence, both in qualitative and quantitative characterization for ceramic glazes, enamels and oxides. it's a recent subject of investigation, its purpose is to discover the presence of toxic substances (Pb, Cd, Sn, As ..) and their quantities if it exists in the manufacturing materials.

  4. Sound Symbolism in Basic Vocabulary

    Directory of Open Access Journals (Sweden)

    Søren Wichmann

    2010-04-01

    Full Text Available The relationship between meanings of words and their sound shapes is to a large extent arbitrary, but it is well known that languages exhibit sound symbolism effects violating arbitrariness. Evidence for sound symbolism is typically anecdotal, however. Here we present a systematic approach. Using a selection of basic vocabulary in nearly one half of the world’s languages we find commonalities among sound shapes for words referring to same concepts. These are interpreted as due to sound symbolism. Studying the effects of sound symbolism cross-linguistically is of key importance for the understanding of language evolution.

  5. ABOUT SOUNDS IN VIDEO GAMES

    Directory of Open Access Journals (Sweden)

    Denikin Anton A.

    2012-12-01

    Full Text Available The article considers the aesthetical and practical possibilities for sounds (sound design in video games and interactive applications. Outlines the key features of the game sound, such as simulation, representativeness, interactivity, immersion, randomization, and audio-visuality. The author defines the basic terminology in study of game audio, as well as identifies significant aesthetic differences between film sounds and sounds in video game projects. It is an attempt to determine the techniques of art analysis for the approaches in study of video games including aesthetics of their sounds. The article offers a range of research methods, considering the video game scoring as a contemporary creative practice.

  6. Magnesium stable isotope ecology using mammal tooth enamel

    Science.gov (United States)

    Martin, Jeremy E.; Vance, Derek; Balter, Vincent

    2015-01-01

    Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (δ13C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotope ratios (δ44Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (δ26Mg) also meet these criteria but a comprehensive understanding of its variability awaits new isotopic data. Here, 11 extant mammal species of known ecology from a single locality in equatorial Africa were sampled for tooth enamel and, together with vegetation and feces, analyzed for δ26Mg, δ13C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that δ26Mg incorporated in tooth enamel becomes heavier from strict herbivores to omnivores/faunivores. Using data from experimentally raised sheep, we suggest that this 26Mg enrichment up the trophic chain is due to a 26Mg enrichment in muscle relative to bone. Notably, it is possible to distinguish omnivores from herbivores, using δ26Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel δ26Mg composition remain to be explored but, in the future, multiproxy approaches would permit a substantial refinement of dietary behaviors or enable accurate trophic reconstruction despite specimen-limited sampling, as is often the case for fossil assemblages.

  7. THE EFFECT OF IRRADIATION ON ENAMEL MICRO-STRUCTURE CHANGES

    Directory of Open Access Journals (Sweden)

    Harun Gunawan

    2015-06-01

    Full Text Available Radiotherapy plays an important role in the management of head and neck carcinoma therapy. The radiation dose ranges from 40 – 70 Gy, depends on the severity and location of the malignancy. Many patients experience an increased dental caries or sensitivity occurrence following radiotherapy. The objective of this study is to analyze the enamel micro-structure changes after irradiation. Nine polished enamel slabs were prepared from impacted 3rd molars. The slabs were flushed in non-ionic distilled water and dried by using air spray and divided into 3 groups, the control, 20 Gy and 40 Gy irradiation group. Irradiations were performed from Co60 using Gammacell-220E, with duration variables to produce the irradiation doses of 20 and 40 Gy. Philips pW370-XRD was used to examine specimen microstructure changes after irradiation. 1-way ANOVA was used for statistics analysis. It was revealed that grain size after 40 Gy irradiation was 66.29±2.7 nm, and after 20 Gy was 51.64±15.8 whilst 43.95±11.1 nm for the control group. The micro-stain deviation of the 40 Gy group was 0.594±0.15 N/m, and 0.45±2.6 N/m for the 20 Gy group, and 0.378±0.27 N/m for control group. Statistic analysis showed significant grain size differences between 40 Gy compared to both 20 Gy and control groups, but not between 20 Gy compared to the control group. Similarly, there were micro-stain differences between 40 Gy compared to 20 Gy and control groups, but not between 20 Gy compared to control group. It was concluded that irradiation with 40 Gy caused elevation of the enamel microstrain and apaite grainsize. Elevation of the enamel microstrain could lead to enamel crack and gave hypersensitive sensation.

  8. Enamel Bond Strength of New Universal Adhesive Bonding Agents.

    Science.gov (United States)

    McLean, D E; Meyers, E J; Guillory, V L; Vandewalle, K S

    2015-01-01

    Universal bonding agents have been introduced for use as self-etch or etch-and-rinse adhesives depending on the dental substrate and clinician's preference. The purpose of this study was to evaluate the shear bond strength (SBS) of composite to enamel using universal adhesives compared to a self-etch adhesive when applied in self-etch and etch-and-rinse modes over time. Extracted human third molars were used to create 120 enamel specimens. The specimens were ground flat and randomly divided into three groups: two universal adhesives and one self-etch adhesive. Each group was then subdivided, with half the specimens bonded in self-etch mode and half in etch-and-rinse mode. The adhesives were applied as per manufacturers' instructions, and composite was bonded using a standardized mold and cured incrementally. The groups were further divided into two subgroups with 10 specimens each. One subgroup was stored for 24 hours and the second for six months in 37°C distilled water and tested in shear. Failure mode was also determined for each specimen. A three-way analysis of variance (ANOVA) found a significant difference between groups based on bonding agent (p0.05). Clearfil SE in etch-and-rinse and self-etch modes had more mixed fractures than either universal adhesive in either mode. Etching enamel significantly increased the SBS of composite to enamel. Clearfil SE had significantly greater bond strength to enamel than either universal adhesive, which were not significantly different from each other.

  9. Preliminary surface analysis of etched, bleached, and normal bovine enamel

    International Nuclear Information System (INIS)

    Ruse, N.D.; Smith, D.C.; Torneck, C.D.; Titley, K.C.

    1990-01-01

    X-ray photoelectron spectroscopic (XPS) and secondary ion-mass spectroscopic (SIMS) analyses were performed on unground un-pumiced, unground pumiced, and ground labial enamel surfaces of young bovine incisors exposed to four different treatments: (1) immersion in 35% H2O2 for 60 min; (2) immersion in 37% H3PO4 for 60 s; (3) immersion in 35% H2O2 for 60 min, in distilled water for two min, and in 37% H3PO4 for 60 s; (4) immersion in 37% H3PO4 for 60 s, in distilled water for two min, and in 35% H2O2 for 60 min. Untreated unground un-pumiced, unground pumiced, and ground enamel surfaces, as well as synthetic hydroxyapatite surfaces, served as controls for intra-tooth evaluations of the effects of different treatments. The analyses indicated that exposure to 35% H2O2 alone, besides increasing the nitrogen content, produced no other significant change in the elemental composition of any of the enamel surfaces investigated. Exposure to 37% H3PO4, however, produced a marked decrease in calcium (Ca) and phosphorus (P) concentrations and an increase in carbon (C) and nitrogen (N) concentrations in unground un-pumiced specimens only, and a decrease in C concentration in ground specimens. These results suggest that the reported decrease in the adhesive bond strength of resin to 35% H2O2-treated enamel is not caused by a change in the elemental composition of treated enamel surfaces. They also suggest that an organic-rich layer, unaffected by acid-etching, may be present on the unground un-pumiced surface of young bovine incisors. This layer can be removed by thorough pumicing or by grinding. An awareness of its presence is important when young bovine teeth are used in a model system for evaluation of resin adhesiveness

  10. Exploring Sound with Insects

    Science.gov (United States)

    Robertson, Laura; Meyer, John R.

    2010-01-01

    Differences in insect morphology and movement during singing provide a fascinating opportunity for students to investigate insects while learning about the characteristics of sound. In the activities described here, students use a free online computer software program to explore the songs of the major singing insects and experiment with making…

  11. Second sound tracking system

    Science.gov (United States)

    Yang, Jihee; Ihas, Gary G.; Ekdahl, Dan

    2017-10-01

    It is common that a physical system resonates at a particular frequency, whose frequency depends on physical parameters which may change in time. Often, one would like to automatically track this signal as the frequency changes, measuring, for example, its amplitude. In scientific research, one would also like to utilize the standard methods, such as lock-in amplifiers, to improve the signal to noise ratio. We present a complete He ii second sound system that uses positive feedback to generate a sinusoidal signal of constant amplitude via automatic gain control. This signal is used to produce temperature/entropy waves (second sound) in superfluid helium-4 (He ii). A lock-in amplifier limits the oscillation to a desirable frequency and demodulates the received sound signal. Using this tracking system, a second sound signal probed turbulent decay in He ii. We present results showing that the tracking system is more reliable than those of a conventional fixed frequency method; there is less correlation with temperature (frequency) fluctuation when the tracking system is used.

  12. See This Sound

    DEFF Research Database (Denmark)

    Kristensen, Thomas Bjørnsten

    2009-01-01

    Anmeldelse af udstillingen See This Sound på Lentos Kunstmuseum Linz, Østrig, som markerer den foreløbige kulmination på et samarbejde mellem Lentos Kunstmuseum og Ludwig Boltzmann Institute Media.Art.Research. Udover den konkrete udstilling er samarbejdet tænkt som en ambitiøs, tværfaglig...

  13. Photoacoustic Sounds from Meteors.

    Energy Technology Data Exchange (ETDEWEB)

    Spalding, Richard E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tencer, John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sweatt, William C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hogan, Roy E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Boslough, Mark B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Spurny, Pavel [Academy of Sciences of the Czech Republic (ASCR), Prague (Czech Republic)

    2015-03-01

    High-speed photometric observations of meteor fireballs have shown that they often produce high-amplitude light oscillations with frequency components in the kHz range, and in some cases exhibit strong millisecond flares. We built a light source with similar characteristics and illuminated various materials in the laboratory, generating audible sounds. Models suggest that light oscillations and pulses can radiatively heat dielectric materials, which in turn conductively heats the surrounding air on millisecond timescales. The sound waves can be heard if the illuminated material is sufficiently close to the observer’s ears. The mechanism described herein may explain many reports of meteors that appear to be audible while they are concurrently visible in the sky and too far away for sound to have propagated to the observer. This photoacoustic (PA) explanation provides an alternative to electrophonic (EP) sounds hypothesized to arise from electromagnetic coupling of plasma oscillation in the meteor wake to natural antennas in the vicinity of an observer.

  14. Sound of Stockholm

    DEFF Research Database (Denmark)

    Groth, Sanne Krogh

    2013-01-01

    Med sine kun 4 år bag sig er Sound of Stockholm relativt ny i det internationale festival-landskab. Festivalen er efter sigende udsprunget af en større eller mindre frustration over, at den svenske eksperimentelle musikscenes forskellige foreninger og organisationer gik hinanden bedene, og...

  15. Making Sense of Sound

    Science.gov (United States)

    Menon, Deepika; Lankford, Deanna

    2016-01-01

    From the earliest days of their lives, children are exposed to all kinds of sound, from soft, comforting voices to the frightening rumble of thunder. Consequently, children develop their own naïve explanations largely based upon their experiences with phenomena encountered every day. When new information does not support existing conceptions,…

  16. The Sounds of Metal

    DEFF Research Database (Denmark)

    Grund, Cynthia M.

    2015-01-01

    Two, I propose that this framework allows for at least a theoretical distinction between the way in which extreme metal – e.g. black metal, doom metal, funeral doom metal, death metal – relates to its sound as music and the way in which much other music may be conceived of as being constituted...

  17. The Universe of Sound

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    Sound Scultor, Bill Fontana, the second winner of the Prix Ars Electronica Collide@CERN residency award, and his science inspiration partner, CERN cosmologist Subodh Patil, present their work in art and science at the CERN Globe of Science and Innovation on 4 July 2013 at 19:00.

  18. Urban Sound Ecologies

    DEFF Research Database (Denmark)

    Groth, Sanne Krogh; Samson, Kristine

    2013-01-01

    . The article concludes that the ways in which recent