Identification of putative dental epithelial stem cells in a lizard with life-long tooth replacement.

Science.gov (United States)

Handrigan, Gregory R; Leung, Kelvin J; Richman, Joy M

2010-11-01

Most dentate vertebrates, including humans, replace their teeth and yet the process is poorly understood. Here, we investigate whether dental epithelial stem cells exist in a polyphyodont species, the leopard gecko (Eublepharis macularius). Since the gecko dental epithelium lacks a histologically distinct site for stem cells analogous to the mammalian hair follicle bulge, we performed a pulse-chase experiment on juvenile geckos to identify label-retaining cells (LRCs). We detected LRCs exclusively on the lingual side of the dental lamina, which exhibits low proliferation rates and is not involved in tooth morphogenesis. Lingual LRCs were organized into pockets of high density close to the successional lamina. A subset of the LRCs expresses Lgr5 and other genes that are markers of adult stem cells in mammals. Also similar to mammalian stem cells, the LRCs appear to proliferate in response to gain of function of the canonical Wnt pathway. We suggest that the LRCs in the lingual dental lamina represent a population of stem cells, the immediate descendents of which form the successional lamina and, ultimately, the replacement teeth in the gecko. Furthermore, their location on the non-tooth-forming side of the dental lamina implies that dental stem cells are sequestered from signals that might otherwise induce them to differentiate.

Tooth replacement related to number of natural teeth in a dentate adult population in Bulgaria: a cross-sectional study

NARCIS (Netherlands)

Damyanov, N.D.; Witter, D.J.; Bronkhorst, E.M.; Creugers, N.H.J.

2013-01-01

PURPOSE: This study aimed to explore the relationships among tooth replacement, number of present natural teeth, and sociodemographic and behavioral factors in an adult population in Bulgaria. MATERIALS AND METHODS: Quota sampling was used to recruit 2,531 dentate subjects aged 20 years and over

Randomized controlled trial to evaluate tooth stain reduction with nicotine replacement gum during a smoking cessation program

LENUS (Irish Health Repository)

Whelton, Helen

2012-06-13

AbstractBackgroundIn addition to its general and periodontal health effects smoking causes tooth staining. Smoking cessation support interventions with an added stain removal or tooth whitening effect may increase motivation to quit smoking. Oral health professionals are well placed to provide smoking cessation advice and support to patients. The objective of the present study was to evaluate the effect of Nicorette® Freshmint Gum used in a smoking cessation programme administered in a dental setting, on extrinsic stain and tooth shade among smokers.MethodsAn evaluator-blinded, randomized, 12-week parallel-group controlled trial was conducted among 200 daily smokers motivated to quit smoking. Participants were randomised to use either the Nicorette® Freshmint Gum or Nicorette® Microtab (tablet). Tooth staining and shade were rated using the modified Lobene Stain Index and the Vita® Shade Guide at baseline, weeks 2, 6 and 12. To maintain consistency with other whitening studies, the primary end-point was the mean change in stain index between baseline and week 6. Secondary variables included changes in stain measurements and tooth shade at the other time points the number of gums or tablets used per day and throughout the trial period; and the number of cigarettes smoked per day. Treatments were compared using analysis of covariance (ANCOVA), using treatment and nicotine dependence as factors and the corresponding baseline measurement as a covariate. Each comparison (modified intention-to-treat) was tested at the 0.05 level, two-sided. Within-treatment changes from baseline were compared using a paired t-test.ResultsAt week 6, the gum-group experienced a reduction in mean stain scores whilst the tablet-group experienced an increase with mean changes of -0.14 and +0.12 respectively, (p = 0.005, ANCOVA). The change in mean tooth shade scores was statistically significantly greater in the gum-group than in the tablet group at 2 (p = 0.015), 6 (p = 0

Varanoid Tooth Eruption and Implantation Modes in a Late Cretaceous Mosasaur.

Science.gov (United States)

Liu, Min; Reed, David A; Cecchini, Giancarlo M; Lu, Xuanyu; Ganjawalla, Karan; Gonzales, Carol S; Monahan, Richard; Luan, Xianghong; Diekwisch, Thomas G H

2016-01-01

Erupting teeth are some of the oldest witnesses of developmental processes in the vertebrate fossil record and provide an important resource for vertebrate cladistics. Here, we have examined a mosasaur jaw fragment from central Texas using ultrathin ground section histology and 3D tomographic imaging to assess features critical for the cladistic placement of mosasaurs among varanoids vs. snakes: (i) the orientation of replacement teeth compared to the major tooth axis, (ii) the occurrence of resorption pits, and (iii) the mode of tooth implantation/attachment to the tooth bearing element (TBE). The replacement tooth studied here developed in an inclined position slightly distal of the deciduous parent tooth, similar to another varanoid squamate, the Gila monster Heloderma suspectum. Ground sections and tomographs also demonstrated that the replacement tooth attachment apparatus was entirely intact and that there was no evidence of mechanical deformation. Sections and tomographs further illustrated that the replacement tooth was located within a bony crypt and the inclination of the crypt matched the inclination of the replacement tooth. These preparations also revealed the presence of a resorption pit within the boundaries of the deciduous tooth that surrounded the developing replacement tooth. This finding suggests that developing mosasaur teeth developed within the walls of resorption pits similar to varanoid tooth germs and unlike developing snake teeth which are surrounded by fibrous connective tissue integuments. Finally, mosasaurs featured pseudo-thecodont tooth implantation with teeth anchored within a socket of mineralized tissue by means of a mineralized periodontal ligament. Together, these data indicate that the moderate inclination of the erupting mosasaur tooth studied here is neither a result of postmortem displacement nor a character representative of snakes, but rather a shared character between Mosasaurs and other varanoids such as Heloderma. In

Varanoid Tooth Eruption and Implantation Modes in a Late Cretaceous Mosasaur

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Min eLiu

2016-05-01

Full Text Available Erupting teeth are some of the oldest witnesses of developmental processes in the vertebrate fossil record and provide an important resource for vertebrate cladistics. Here we have examined a mosasaur jaw fragment from central Texas using ultrathin ground section histology and 3D tomographic imaging to assess features critical for the cladistic placement of mosasaurs among varanoids versus snakes: (i the orientation of replacement teeth compared to the major tooth axis, (ii the occurrence of resorption pits, and (iii the mode of tooth implantation/attachment to the tooth bearing element. The replacement tooth studied here developed in an inclined position slightly distal of the deciduous parent tooth, similar to another varanoid squamate, the Gila monster Heloderma suspectum. Ground sections and tomographs also demonstrated that the replacement tooth attachment apparatus was entirely intact and that there was no evidence of mechanical deformation. Sections and tomographs further illustrated that the replacement tooth was located within a bony crypt and the inclination of the crypt matched the inclination of the replacement tooth. These preparations also revealed the presence of a resorption pit within the boundaries of the deciduous tooth that surrounded the developing replacement tooth. This finding suggests that developing mosasaur teeth developed within the walls of resorption pits similar to varanoid tooth germs and unlike developing snake teeth which are surrounded by fibrous connective tissue integuments. Finally, mosasaurs featured pseudo-thecodont tooth implantation with teeth anchored within a socket of mineralized tissue by means of a mineralized periodontal ligament. Together, these data indicate that the moderate inclination of the erupting mosasaur tooth studied here is neither a result of postmortem displacement nor a character representative of snakes, but rather a shared character between Mosasaurs and other varanoids such as

Massive clot formation after tooth extraction

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Santosh Hunasgi

2015-01-01

Full Text Available Oral surgical procedures mainly tooth extraction can be related with an extended hemorrhage owed to the nature of the process resulting in an "open wound." The attempt of this paper is to present a case of massive postoperative clot formation after tooth extraction and highlight on the oral complications of surgical procedures. A 32-year-old male patient reported to the Dental Clinic for evaluation and extraction of grossly decayed 46. Clinical evaluation of 46 revealed root stumps. Extraction of the root stumps was performed, and it was uneventful. Hemostasis was achieved and postsurgical instructions were specified to the patient. The patient reported to the clinic, the very subsequent morning with a criticism of bleeding at the extraction site. On clinical examination, bleeding was noted from the socket in relation to 46. To control bleeding, oral hemostatic drugs Revici - E (Ethamsylate 500 mg was prescribed and bleeding was stopped in 2 h. However, a massive clot was formed at the extraction site. Further, this clot resolved on its own in 1-week time. Despite the fact that dental extraction is considered to be a minor surgical procedure, some cases may present with life-threatening complications including hemorrhage. Vigilant and significant history taking, physical and dental examinations prior to dental procedures are a must to avoid intraoperative and postoperative complications.

Evaluation of aesthetics of implant-supported single-tooth replacements using different bone augmentation procedures : A prospective randomized clinical study

NARCIS (Netherlands)

Meijndert, Leo; Meijer, Henny J. A.; Stellingsma, Kees; Stegenga, Boudewijn; Raghoebar, Gerry M.

2007-01-01

Objectives: The aim of this study was to evaluate the aesthetics of implant-supported single-tooth replacements using different augmentation procedures in a prospective study with the use of an objective rating index and with a subjective patient questionnaire, and to compare the results with each

Structure, attachment, replacement and growth of teeth in bluefish, Pomatomus saltatrix (Linnaeus, 1776), a teleost with deeply socketed teeth.

Science.gov (United States)

Bemis, William E; Giuliano, Anne; McGuire, Betty

2005-01-01

Tooth replacement poses many questions about development, pattern formation, tooth attachment mechanisms, functional morphology and the evolution of vertebrate dentitions. Although most vertebrate species have polyphyodont dentitions, detailed knowledge of tooth structure and replacement is poor for most groups, particularly actinopterygians. We examined the oral dentition of the bluefish, Pomatomus saltatrix, a pelagic and coastal marine predator, using a sample of 50 individuals. The oral teeth are located on the dentary and premaxillary bones, and we scored each tooth locus in the dentary and premaxillary bones using a four-part functional classification: absent (A), incoming (I), functional (F=fully ankylosed) or eroding (E). The homodont oral teeth of Pomatomus are sharp, deeply socketed and firmly ankylosed to the bone of attachment. Replacement is intraosseus and occurs in alternate tooth loci with long waves of replacement passing from rear to front. The much higher percentage of functional as opposed to eroding teeth suggests that replacement rates are low but that individual teeth are quickly lost once erosion begins. Tooth number increases ontogenetically, ranging from 15-31 dentary teeth and 15-39 premaxillary teeth in the sample studied. Teeth increase in size with every replacement cycle. Remodeling of the attachment bone occurs continuously to accommodate growth. New tooth germs originate from a discontinuous dental lamina and migrate from the lingual (dentary) or labial (premaxillary) epithelium through pores in the bone of attachment into the resorption spaces beneath the existing teeth. Pomatomus shares unique aspects of tooth replacement with barracudas and other scombroids and this supports the interpretation that Pomatomus is more closely related to scombroids than to carangoids.

Tooth engineering: searching for dental mesenchymal cells sources.

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Laetitia eKeller

2011-03-01

Full Text Available The implantation of cultured re-associations between embryonic dental mesenchymal cells and epithelial cells from mouse molars at ED14 allowed making full teeth with crown, root, periodontal ligament fibers and bone. Although representing valuable tools to set up methodologies embryonic cells are not easily available. This work thus aimed to replace the embryonic cells by dental mesenchymal cell lines or cultured expanded embryonic cells, and to test their ability to mediate tooth development in vitro when re-associated with a competent dental epithelium. Histology, immunostaining and RT-PCR allowed getting complementary sets of results. Two different immortalized cell lines from ED18 dental mesenchyme failed in mediating tooth formation. The potentialities of embryonic dental mesenchymal cells decreased from ED14 to ED16 and were lost at ED18. This is likely related to a change in the mesenchymal cell phenotype and/or populations during development. Attempts to cultivate ED14 or ED16 embryonic dental mesenchymal cells prior to re-association led to the loss of their ability to support tooth development. This was accompanied by a down-regulation of Fgf3 transcription. Supplementation of the culture medium with FGF2 allowed restoring Fgf3 expression, but not the ability of mesenchymal cells to engage in tooth formation. Altogether, these observations suggest that a competent cell population exists in the dental mesenchyme at ED14, progressively decreases during development, and cannot as such be maintained in vitro. This study evidenced the need for specific conditions to maintain the ability of dental mesenchymal cells to initiate whole tooth formation, when re-associated with an odontogenic epithelium. Efforts to improve the culture conditions will have to be combined with attempts to characterize the competent cells within the dental mesenchyme.

[Application of single-retainer all-ceramic resin-bonded fixed partial denture in replacing single anterior tooth].

Science.gov (United States)

Lili, Yang; Debiao, Du; Ruoyu, Ning; Deying, Chen; Junling, Wu

2017-08-01

Objective In this study, we aimed to evaluate the clinical effect of single-retainer all-ceramic resin-bonded fixed partial denture (RBFPD) on the single anterior tooth loss patients. Methods A total of 20 single-retainer all-ceramic RBFPD
were fabricated and evaluated in a two-year follow-up observation. The restorations were examined on the basis of the American Public Health Association (APHA) criteria. Results A total of 20 single-retainer all-ceramic RBFPD achieved class A evaluation after a six-month follow-up observation. One single-retainer all-ceramic RBFPD was classified as class B for secondary caries after a one-year follow-up observation. After a two-year follow-up observation, one single-retainer all-ceramic RBFPD was classified as class B because of secondary caries, and one single-retainer all-ceramic RBFPD was classified as class B because of fracture. Conclusion Single-retainer all-ceramic RBFPD is a promising and optional method in replacing single anterior tooth.

Recent advances in engineering of tooth and tooth structures using postnatal dental cells

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Masaki J. Honda

2010-02-01

This review focuses on the performance of postnatal and adult dental cells that have been used for generating teeth. Their ability to contribute to tooth development was assessed in the omentum or in the tooth socket. Adult dental cells were limited in their potential owing to various parameters. From these results described, new approaches for regenerated teeth are proposed in this review. One strategy to replace teeth is tooth root engineering using tissue from postnatal teeth. Since the enamel organ epithelium disappears after tooth maturation, the epithelial rest cells of Malassez were evaluated to determine their capacity to generate enamel. From these results, it is suggested that erupted mature teeth have cell sources with the capacity to produce tooth root. The development of biological approaches for tooth root regeneration using postnatal dental cells is promising and remains one of the greatest challenges in the dental field in the years to come.

Tooth eruption and browridge formation.

Science.gov (United States)

Russell, M D

1982-05-01

One of the most reasonable hypotheses regarding the functional significance of the browridge is that the supraorbital torus forms in response to masticatory stress during development. Oyen, Walker, and Rice (1979) have recently proposed a model that tests this hypothesis: if browridges are functionally related to masticatory stresses on the cranial vault, then changes in the biomechanics of the masticatory system ought to be reflected by changes in the browridge. To test their model they attempted to relate biomechanical discontinuities resulting from tooth eruption to episodes of bone deposition on the supraorbital tori of a developmental series of dry Papio crania. This paper reports on a parallel test of the model on a cross-sectional sample of Australian Aboriginal juvenile crania. This sample showed no relation between tooth eruption and the supraorbital surface morphology thought to be indicative of active bone deposition. It is also demonstrated that no significant relationship between tooth eruption and episodes of bone deposition is shown by the Papio sample. It is concluded that the use of small cross-sectional samples of dry crania does not provide a valid test of the model.

Factors associated with tooth loss and prosthodontic status among Sudanese adults.

Science.gov (United States)

Khalifa, Nadia; Allen, Patrick F; Abu-bakr, Neamat H; Abdel-Rahman, Manar E

2012-01-01

A study was conducted to determine the degree of tooth loss, factors influencing tooth loss, and the extent of prosthodontic rehabilitation in Sudanese adults (≥ 16 years old) attending outpatient clinics in Khartoum State. Pearson and multivariate analyses were used to examine the relationships between tooth loss and specific characteristics determined through interviews and clinical examinations. The mean number of missing teeth was 3.6 (SD, 4.9) and the prevalence of edentulism was 0.1%. The prevalence of tooth loss (missing at least one tooth) was 78%; 66.9% of tooth loss was due to caries, and 11.2% was attributable to other reasons. Prosthetic replacement of missing teeth was evident in 3%, whereas a need for prosthetic replacement was evident in 57%. Having teeth was associated with age, gender, and socioeconomic status; tooth loss due to caries was associated with age, tribe, frequency of tooth-brushing, and a low rate of dental consultation. Tooth loss due to other reasons was associated with age, tribe, education, periodontal pocketing, tobacco use, tooth wear, and prosthetic status. The results of the present study indicated that the major cause of tooth loss was dental caries, thus emphasizing the importance of a public prevention-based healthcare program. Replacement of missing teeth was uncommon in the study subjects, which may reflect lack of access to this type of oral healthcare.

Long-term neuroplasticity of the face primary motor cortex and adjacent somatosensory cortex induced by tooth loss can be reversed following dental implant replacement in rats.

Science.gov (United States)

Avivi-Arber, Limor; Lee, Jye-Chang; Sood, Mandeep; Lakschevitz, Flavia; Fung, Michelle; Barashi-Gozal, Maayan; Glogauer, Michael; Sessle, Barry J

2015-11-01

Tooth loss is common, and exploring the neuroplastic capacity of the face primary motor cortex (face-M1) and adjacent primary somatosensory cortex (face-S1) is crucial for understanding how subjects adapt to tooth loss and their prosthetic replacement. The aim was to test if functional reorganization of jaw and tongue motor representations in the rat face-M1 and face-S1 occurs following tooth extraction, and if subsequent dental implant placement can reverse this neuroplasticity. Rats (n = 22) had the right maxillary molar teeth extracted under local and general anesthesia. One month later, seven rats had dental implant placement into healed extraction sites. Naive rats (n = 8) received no surgical treatment. Intracortical microstimulation (ICMS) and recording of evoked jaw and tongue electromyographic responses were used to define jaw and tongue motor representations at 1 month (n = 8) or 2 months (n = 7) postextraction, 1 month postimplant placement, and at 1-2 months in naive rats. There were no significant differences across study groups in the onset latencies of the ICMS-evoked responses (P > 0.05), but in comparison with naive rats, tooth extraction caused a significant (P rats. These novel findings suggest that face-M1 and adjacent face-S1 may play a role in adaptive mechanisms related to tooth loss and their replacement with dental implants. © 2015 Wiley Periodicals, Inc.

3-D analysis of tooth formation and eruption in patients with craniofacial anomalies

DEFF Research Database (Denmark)

Kreiborg, Sven; Larsen, Per; Bro-Nielsen, Morten

1996-01-01

A number of craniofacial anomalies or syndromes involve severe disturbances of tooth formation and eruption (e.g. Apert syndrome, Crouzon syndrome, tricho-dento-osseous syndrome, cleidocranial dysplasia, and cleft lip and palate). So far, studies of these dental problems have been limited to two...

Autotransplantation of a Supernumerary Tooth to Replace a Misaligned Incisor with Abnormal Dimensions and Morphology: 2-Year Follow-Up

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R. Ebru Tirali

2013-01-01

Full Text Available Autotransplantation is a viable treatment option to restore esthetics and function impaired by abnormally shaped teeth when a suitable donors tooth is available. This paper describes the autotransplantation and 2-year follow-up of a supernumerary maxillary incisor as a replacement to a misaligned maxillary incisor with abnormal crown morphology and size. The supernumerary incisor was immediately autotransplanted into the extraction site of the large incisor and was stabilized with a bonded semirigid splint for 2 weeks. Fixed orthodontic therapy was initiated 3 months after autotransplantation. Ideal alignment of the incisors was accomplished after 6 months along with radiographic evidence of apical closure and osseous/periodontal regeneration. In autogenous tooth transplantation, a successful clinical outcome can be achieved if the cases are selected and treated properly.

Study of formation constant of molybdophosphate and it's application in the product of xenotime sand, tooth and bone

International Nuclear Information System (INIS)

Samin; Lahagu, F.; Basuki, K. T.; Ernawati, F.

1996-01-01

The formation constant of molybdophosphate complex and it's application in the product of xenotime sand, tooth and bone have been studied by spectrophotometric method. The molybdophosphate complex were formed from reaction between phosphate and molybdate on several of pH in the strong acid condition (pH = 0.45 - 0.71) and several of phosphate mole fraction (0.01 - 0.08). The several of complex formation reactions were determined by matrix disintegration technique. Molybdophosphate complex were founded three forms i.e. (P 2 Mo 18 O 62 ) 6- or 9 MPA, (PMo 11 O 39 ) 7- or 11 MPA and (PMo 12 O 40 ) 3- or 12 MPA. The formation constant of (PMo 12 O 40 ) 3- complex was found β = 10 46.95 ± 10 3.7 , while for (P 2 Mo 18 O 62 ) 6- and (PMo 11 O 39 ) 7- were not detected. The application in samples were found the concentration of P in product of xenotime sand : 5.37±0.08 μg/ml, in canine-tooth: 10.40 - 19.49 % in cutting-tooth : 11.08 - 18.05 % and in bone 10.94 - 14.29 %. (author)

Natural tooth pontic with splinting of periodontally weakened teeth using fiber-reinforced composite resin

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Gauri Srinidhi

2014-01-01

Full Text Available Replacement of missing anterior teeth due to periodontal reasons is challenging due to the poor support of abutment teeth. This prevents the use of fixed partial dentures (FPDs. Fiber-reinforced splinting provides a viable alternative to the dentist while choosing a treatment plan in replacing missing anterior teeth in periodontally compromised patients as opposed to conventional modalities like FPDs or removable partial dentures. Replacing missing teeth using either patient′s own tooth or a denture tooth as pontic can be done by splinting adjacent teeth with fiber reinforced composite. The splinting has an additional advantage of stabilizing adjacent mobile teeth. This case report details the case selection, procedure with follow-up of a case where the natural extracted tooth of the patient was used as pontic to replace a missing anterior tooth. The splinting was done with fiber reinforced composite resin. Fiber-reinforced composite resin splinting of patient′s extracted natural tooth is economical, fast, and easy to use chairside technique with the added benefit of periodontal stabilization.

Tooth microwear formation rate in Gasterosteus aculeatus.

Science.gov (United States)

Baines, D C; Purnell, M A; Hart, P J B

2014-05-01

Tooth microwear feature densities were significantly increased in a population of laboratory-reared three-spined stickleback Gasterosteus aculeatus in four days, after they were transferred from a limnetic feeding regime to a benthic feeding regime. These results show that even in aquatic vertebrates with non-occluding teeth, changes in feeding can cause changes in tooth microwear in just a few days, as in mammals. © 2014 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of The Fisheries Society of the British Isles.

Tooth breakage in patients injected with 224Ra

International Nuclear Information System (INIS)

Sonnabend, E.; Spiess, H.; Mays, C.W.

1986-01-01

Tooth breakage has been common among the 224 Ra patients, especially those injected as teenagers. The fracture of 1 or more teeth was reported by 26% (8/31) of boys and 23% (7/30) of girls injected with 224 Ra at 16-20 years of age. Combining results from all age groups, the incidence of tooth fractures increased significantly with dose (P=0.01). Unlike the normal loss of permanent teeth by periodontal disease, in which the entire tooth is lost, the tooth loss following 224 Ra injection was primarily from tooth resorption near the gum line causing the tooth crowns to break off easily. Eventually the tooth roots may either become incorporated into the jawbone or are resorbed and replaced with bone. These tooth fractures resembled those observed in the U.S. radium dial painters and in dogs injected with bone-seeking α-emitters. (orig.)

Anomalies of tooth formation in hypohidrotic ectodermal dysplasia

DEFF Research Database (Denmark)

Lexner, Michala O; Bardow, Allan; Hertz, Jens Michael

2007-01-01

OBJECTIVE: The X-linked hypohidrotic ectodermal dysplasia (HED) is the most common type of ectodermal dysplasia. The clinical identification of possible heterozygous females can be difficult because of the varying degrees of clinical signs caused by X-chromosome inactivation. This study is the fi......OBJECTIVE: The X-linked hypohidrotic ectodermal dysplasia (HED) is the most common type of ectodermal dysplasia. The clinical identification of possible heterozygous females can be difficult because of the varying degrees of clinical signs caused by X-chromosome inactivation. This study...... affected males had multiple missing permanent teeth and tooth malformations. The heterozygous females had a significantly higher frequency of agenesis of permanent teeth compared to normative data. The heterozygous females had an increased prevalence of tooth malformations and reduced tooth size...

A PLIOSAURID TOOTH FROM THE ARGILLE VARICOLORI FORMATION NEAR CASTELVECCHIO DI PRIGNANO (MODENA PROVINCE, NORTHERN ITALY

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CESARE A. PAPAZZONI

2003-11-01

Full Text Available The first discovery of a Cretaceous pliosaurid tooth in Italy is reported. It comes from the Cenomanian-lower Campanian Argille Varicolori Formation near Castelvecchio di Prignano (Modena Province, northern Italy. Excepting this new specimen, Italy's only reported pliosaurid is a humerus from the Upper Cretaceous of Zavattarello near Pavia. The tooth morphology allows it to be ascribed to Polyptychodon interruptus Owen, 1841, a species only reported thus far from northern-central Europe (England, Germany, and the Czech Republic. This suggests the presence of marine reptile remains in the northern Apennines may have been underestimated. 

AN EARLY JURASSIC SAUROPOD TOOTH FROM PATAGONIA (CAÑADÓN ASFALTO FORMATION: IMPLICATIONS FOR SAUROPOD DIVERSITY

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Carballido, José L

2017-12-01

Full Text Available Eusauropods were a group of herbivorous dinosaurs that evolved during the Early Jurassic and dominated the terrestrial ecosystems throughout the Jurassic and Cretaceous. A peak of diversity is represented by the Late Jurassic, when most of the lineages of the derived clade, Neosauropoda, are represented. Different lineages of eusauropods differ in several morphological aspects, including a great diversity in gathering strategies, inferred by their dentition morphology and wear facets. Here we describe a new tooth morphotype that can be well differentiated from any other tooth recovered from the Cañadón Asfalto Formation (Lower Jurassic-Middle-Jurassic. Therefore this new tooth morphology increase the evidence of a high diversity of sauropods during that time as well as providing evidence of advanced characters in the dentition of some Early Jurassic sauropods (e.g., subcylindrical and narrow crowns with single apical wear facet.

The role of microbial iron reduction in the formation of Proterozoic molar tooth structures

Science.gov (United States)

Hodgskiss, Malcolm S. W.; Kunzmann, Marcus; Poirier, André; Halverson, Galen P.

2018-01-01

Molar tooth structures are poorly understood early diagenetic, microspar-filled voids in clay-rich carbonate sediments. They are a common structure in sedimentary successions dating from 2600-720 Ma, but do not occur in rocks older or younger, with the exception of two isolated Ediacaran occurrences. Despite being locally volumetrically significant in carbonate rocks of this age, their formation and disappearance in the geological record remain enigmatic. Here we present iron isotope data, supported by carbon and oxygen isotopes, major and minor element concentrations, and total organic carbon and sulphur contents for 87 samples from units in ten different basins spanning ca. 1900-635 Ma. The iron isotope composition of molar tooth structures is almost always lighter (modal depletion of 2‰) than the carbonate or residue components in the host sediment. We interpret the isotopically light iron in molar tooth structures to have been produced by dissimilatory iron reduction utilising Fe-rich smectites and Fe-oxyhydroxides in the upper sediment column. The microbial conversion of smectite to illite results in a volume reduction of clay minerals (∼30%) while simultaneously increasing pore water alkalinity. When coupled with wave loading, this biogeochemical process is a viable mechanism to produce voids and subsequently precipitate carbonate minerals. The disappearance of molar tooth structures in the mid-Neoproterozoic is likely linked to a combination of a decrease in smectite abundance, a decline in the marine DIC reservoir, and an increase in the concentration of O2 in shallow seawater.

Single-tooth replacement by osseointegrated Astra Tech dental implants: a 2-year report

DEFF Research Database (Denmark)

Karlsson, U; Gotfredsen, K; Olsson, C

1998-01-01

This study presents the outcome of single-tooth restorations supported by Astra Tech single-tooth implants followed for 2 years. Forty-seven implants were placed in the same number of patients. Forty-three patients attended the second recall visit, and none of the evaluated implants have been...

Clinical application of single-tooth replacement with ankylos implant system

International Nuclear Information System (INIS)

Yang Xu; Liu Xue; Zhang Heng; Deng Yan; Guo Zhaozhong; Zhang Yufeng

2011-01-01

Objective: To evaluate the clinical effects of Ankylos implant system to restore the loss of single-tooth. Methods: 90 cases with loss of single-tooth were selected and treated with routinely two-stage surgery. When the patients presented with deficient alveolar ridge, guided bone regeneration (GBR), osteotome sinus floor elevation, lateral antrostomy surgery with simultaneous placement of implant were applied. They were restored with platinum ceramic crown. All the implants were followed up, and the records were kept about stability of the implant and abutment, the status of surrounding soft tissue, sealability of implant abutment junction and the marginal bone lossing through X-ray checking,and satisfaction of the patients to mastication and aspect of the restorations. The follow-up time was 1-2.5 years. Results: Among the cases,one case had peri-implant inflammation, and one case had porcelain dropped. No loosening occurred in the other implants and abuments. Implant abutment junction was sealed well. The marginal bone loss 1 year after final restoration was less than 1 mm. Soft tissue surrounding implants was healthy. The satisfaction rate was 98.9% (89/90). According to standard of implant success, 88 cases were successful, the 2.5-year cumulative success rate was 97.8%, 2 cases failed, and the failure rate was 2.2 %. Conclusion: A satisfactory treatment effects could be gotten by using Ankylos implant system to restore the loss of single-tooth. (authors)

Natural Tooth Pontic: An Instant Esthetic Option for Periodontally Compromised Teeth—A Case Series

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Rishi Raj

2016-01-01

Full Text Available Sudden tooth loss in the esthetic zone of the maxillary or mandibular anterior region can be due to trauma, periodontal disease, or endodontic failure. The treatment options for replacing the missing tooth can vary between removable prosthesis, tooth-supported prosthesis, and implant-supported prosthesis. Irrespective of the final treatment, the first line of management would be to provisionally restore the patient’s esthetic appearance at the earliest, while functionally stabilizing the compromised arch. Using the patient’s own natural tooth as a pontic offers the benefits of being the right size, shape, and color and provides exact repositioning in its original intraoral three-dimensional position. Additionally, using the patient’s platelet concentrate (platelet rich fibrin facilitates early wound healing and preservation of alveolar ridge shape following tooth extraction. The abutment teeth can also be preserved with minimal or no preparation, thus keeping the technique reversible, and can be completed at the chair side thereby avoiding laboratory costs. This helps the patient better tolerate the effect of tooth loss psychologically. The article describes a successful, immediate, and viable technique for rehabilitation of three different patients requiring replacement of a single periodontally compromised tooth in an esthetic region.

The single-tooth implant treatment of congenitally missing maxillary lateral incisors using angled abutments: A clinical report

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Suleyman Hakan Tuna

2009-01-01

Full Text Available The maxillary lateral incisor is the second most common congenitally absent tooth. There are several treatment options for replacing the missing maxillary lateral incisor, including canine substitution, tooth-supported restoration, or single-tooth implant. Dental implants are an appropriate treatment option for replacing missing maxillary lateral incisor teeth in adolescents when their dental and skeletal development is complete. This case report presents the treatment of a patient with congenitally missing maxillary lateral incisors using dental implants with angled abutments.

Mate tea (Ilex paraguariensis) improves bone formation in the alveolar socket healing after tooth extraction in rats.

Science.gov (United States)

Brasilino, Matheus da Silva; Stringhetta-Garcia, Camila Tami; Pereira, Camila Scacco; Pereira, Ariana Aparecida Ferreira; Stringhetta, Karina; Leopoldino, Andréia Machado; Crivelini, Marcelo Macedo; Ervolino, Edilson; Dornelles, Rita Cássia Menegati; de Melo Stevanato Nakamune, Ana Cláudia; Chaves-Neto, Antonio Hernandes

2018-04-01

The objective of this study was to investigate the effects of mate tea (MT) [Ilex paraguariensis] on alveolar socket healing after tooth extraction. Sixteen male rats were divided into MT and control groups. MT was administered by intragastric gavage at a dose of 20 mg/kg/day for 28 days before and 28 days after right maxillary incisor extraction. The control group received an equal volume of water. Histopathological and histometric analysis of the neoformed bone area and osteocyte density were performed, as well as immunohistochemical analysis of osteocalcin (OCN), receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG), tartrate-resistant acid phosphatase (TRAP), and manganese superoxide dismutase (MnSOD) in the alveolar socket. Calcium, phosphorus, alkaline phosphatase (ALP) activity, total antioxidant capacity (TAC), and malondialdehyde (MDA) were measured in plasma, whereas TRAP activity was determined in serum. Histometry evidenced an increase in bone area (P alveolar socket healing on day 28 after tooth extraction. Regular MT ingestion improves the antioxidant defenses and bone formation, which is beneficial for alveolar socket bone healing after tooth extraction.

Mesenchymal Wnt/β-catenin signaling limits tooth number.

Science.gov (United States)

Järvinen, Elina; Shimomura-Kuroki, Junko; Balic, Anamaria; Jussila, Maria; Thesleff, Irma

2018-02-21

Tooth agenesis is one of the predominant developmental anomalies in humans, usually affecting the permanent dentition generated by sequential tooth formation and, in most cases, caused by mutations perturbing epithelial Wnt/β-catenin signaling. In addition, loss-of-function mutations in the Wnt feedback inhibitor AXIN2 lead to human tooth agenesis. We have investigated the functions of Wnt/β-catenin signaling during sequential formation of molar teeth using mouse models. Continuous initiation of new teeth, which is observed after genetic activation of Wnt/β-catenin signaling in the oral epithelium, was accompanied by enhanced expression of Wnt antagonists and a downregulation of Wnt/β-catenin signaling in the dental mesenchyme. Genetic and pharmacological activation of mesenchymal Wnt/β-catenin signaling negatively regulated sequential tooth formation, an effect partly mediated by Bmp4. Runx2 , a gene whose loss-of-function mutations result in sequential formation of supernumerary teeth in the human cleidocranial dysplasia syndrome, suppressed the expression of Wnt inhibitors Axin2 and Drapc1 in dental mesenchyme. Our data indicate that increased mesenchymal Wnt signaling inhibits the sequential formation of teeth, and suggest that Axin2 / Runx2 antagonistic interactions modulate the level of mesenchymal Wnt/β-catenin signaling, underlying the contrasting dental phenotypes caused by human AXIN2 and RUNX2 mutations. © 2018. Published by The Company of Biologists Ltd.

Dental-derived Stem Cells and whole Tooth Regeneration: an Overview

OpenAIRE

Dannan, Aous

2009-01-01

The need for new dental tissue-replacement therapies is evident in recent reports which reveal startling statistics regarding the high incidence of tooth decay and tooth loss. Recent advances in the identification and characterization of dental stem cells, and in dental tissue-engineering strategies, suggest that bioengineering approaches may successfully be used to regenerate dental tissues and whole teeth. Interest in dental tissue-regeneration applications continues to increase as clinical...

Advances and perspectives in tooth tissue engineering.

Science.gov (United States)

Monteiro, Nelson; Yelick, Pamela C

2017-09-01

Bio-engineered teeth that can grow and remodel in a manner similar to that of natural teeth have the potential to serve as permanent replacements to the currently used prosthetic teeth, such as dental implants. A major challenge in designing functional bio-engineered teeth is to mimic both the structural and anisotropic mechanical characteristics of the native tooth. Therefore, the field of dental and whole tooth regeneration has advanced towards the molecular and nanoscale design of bio-active, biomimetic systems, using biomaterials, drug delivery systems and stem cells. The focus of this review is to discuss recent advances in tooth tissue engineering, using biomimetic scaffolds that provide proper architectural cues, exhibit the capacity to support dental stem cell proliferation and differentiation and sequester and release bio-active agents, such as growth factors and nucleic acids, in a spatiotemporal controlled manner. Although many in vitro and in vivo studies on tooth regeneration appear promising, before tooth tissue engineering becomes a reality for humans, additional research is needed to perfect methods that use adult human dental stem cells, as opposed to embryonic dental stem cells, and to devise the means to generate bio-engineered teeth of predetermined size and shape. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Augmented BMPRIA-mediated BMP signaling in cranial neural crest lineage leads to cleft palate formation and delayed tooth differentiation.

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Lu Li

Full Text Available The importance of BMP receptor Ia (BMPRIa mediated signaling in the development of craniofacial organs, including the tooth and palate, has been well illuminated in several mouse models of loss of function, and by its mutations associated with juvenile polyposis syndrome and facial defects in humans. In this study, we took a gain-of-function approach to further address the role of BMPR-IA-mediated signaling in the mesenchymal compartment during tooth and palate development. We generated transgenic mice expressing a constitutively active form of BmprIa (caBmprIa in cranial neural crest (CNC cells that contributes to the dental and palatal mesenchyme. Mice bearing enhanced BMPRIa-mediated signaling in CNC cells exhibit complete cleft palate and delayed odontogenic differentiation. We showed that the cleft palate defect in the transgenic animals is attributed to an altered cell proliferation rate in the anterior palatal mesenchyme and to the delayed palatal elevation in the posterior portion associated with ectopic cartilage formation. Despite enhanced activity of BMP signaling in the dental mesenchyme, tooth development and patterning in transgenic mice appeared normal except delayed odontogenic differentiation. These data support the hypothesis that a finely tuned level of BMPRIa-mediated signaling is essential for normal palate and tooth development.

The junctional epithelium originates from the odontogenic epithelium of an erupted tooth.

Science.gov (United States)

Yajima-Himuro, Sara; Oshima, Masamitsu; Yamamoto, Gou; Ogawa, Miho; Furuya, Madoka; Tanaka, Junichi; Nishii, Kousuke; Mishima, Kenji; Tachikawa, Tetsuhiko; Tsuji, Takashi; Yamamoto, Matsuo

2014-05-02

The junctional epithelium (JE) is an epithelial component that is directly attached to the tooth surface and has a protective function against periodontal diseases. In this study, we determined the origin of the JE using a bioengineered tooth technique. We transplanted the bioengineered tooth germ into the alveolar bone with an epithelial component that expressed green fluorescence protein. The reduced enamel epithelium from the bioengineered tooth fused with the oral epithelium, and the JE was apparently formed around the bioengineered tooth 50 days after transplantation. Importantly, the JE exhibited green fluorescence for at least 140 days after transplantation, suggesting that the JE was not replaced by oral epithelium. Therefore, our results demonstrated that the origin of the JE was the odontogenic epithelium, and odontogenic epithelium-derived JE was maintained for a relatively long period.

Stem cells for tooth engineering

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G Bluteau

2008-07-01

Full Text Available Tooth development results from sequential and reciprocal interactions between the oral epithelium and the underlying neural crest-derived mesenchyme. The generation of dental structures and/or entire teeth in the laboratory depends upon the manipulation of stem cells and requires a synergy of all cellular and molecular events that finally lead to the formation of tooth-specific hard tissues, dentin and enamel. Although mesenchymal stem cells from different origins have been extensively studied in their capacity to form dentin in vitro, information is not yet available concerning the use of epithelial stem cells. The odontogenic potential resides in the oral epithelium and thus epithelial stem cells are necessary for both the initiation of tooth formation and enamel matrix production. This review focuses on the different sources of stem cells that have been used for making teeth in vitro and their relative efficiency. Embryonic, post-natal or even adult stem cells were assessed and proved to possess an enormous regenerative potential, but their application in dental practice is still problematic and limited due to various parameters that are not yet under control such as the high risk of rejection, cell behaviour, long tooth eruption period, appropriate crown morphology and suitable colour. Nevertheless, the development of biological approaches for dental reconstruction using stem cells is promising and remains one of the greatest challenges in the dental field for the years to come.

Telemedicine consulting in the patient preparation and planning of prosthetic tooth replacement.

Science.gov (United States)

Mladenović, Dragan; Tosić, Goran; Zivković, Dusan; Djindjić, Natasa; Mladenović, Lidija; Mladenović, Sanja; Marković, Ivana

2013-09-01

In the management of edentulous spaces, there is a permanent need of a dentist-prosthetician in charge to consult other specialists. Modern telemedicine, based on powerful computer and telecomunication systems, offers an adequate answer to these challenges, being able to transfer and obtain clinical data and consultation information over large distances. Using smartphone or a computer, the teleconsultant acces the system, downloads and review the data and photographs and gave suggestions. The system then enables direct, real time contact with the consultant, chat, or directs them to contact each other by phone. We presented telemedicine consulting in the patient preparation and planning of prosthetic tooth replacement in 3 cases with different teleconsultation requirements: the first case for prosthetic rehabilitation of his upper teeth, the second one for prosthetic management of his partial edentulousness and "a growth on his gums" in the vestibular region of the frontal teeth and the third one for prosthetic management of total edentulousness of her upper jaw. We used the system of telemedicine in dentistry, established at the Faculty of Medicine in Kosovska Mitrovica. The operation was based on the computer application system XPA3 Online, computer networking and mobile smartphone network. All consultations were succefull with no need for further procedures in regional center. The use of a mobile smartphone has brought about the mobility and availability of teleconsultant specialists in an extent never seen before. Prostheticians are thus able to offer better service to their patients and improve the quality of management of partially or totally edentulous patients, especially in rural areas.

Effect of mangosteen peel extract combined with demineralized freezed-dried bovine bone xenograft on osteoblast and osteoclast formation in post tooth extraction socket

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Utari Kresnoadi

2016-12-01

Full Text Available Background: Tooth extraction, a common procedure in dentistry, can cause bone resorption during socket healing. Therefore, it is important to perform socket preservation procedure to maintain alveolar bone. Providing a combination of mangosteen peel extract with demineralized freezed-dried bovine bone xenograft (DFDBBX in tooth extraction socket was expected to accelerate alveol bone formation. Purpose: This study aims to determine the effect of mangosteen peel extract combined with DFDBBX introduced into the socket of post tooth extraction on the formation of osteoblasts and osteoclasts. Method: Twenty-eight (28 Cavia cobayas were divided into four groups. Extraction to the lower left incisor of Cavia cobaya was performed. The extraction socket was filled with 25 gram of PEG (group I as a control, active materials consisted of mangosteen peel extract and DFDBBX 0.5% (group II, active materials consisted of mangosteen peel extract and DFDBBX 1% (group III, and active materials consisted of mangosteen peel extract and DFDBBX 2% (group IV. After thirty days, those Cavia cobayas were sacrificed. By using HE on Histopatological examination, the number of osteoblasts and osteoclasts were measured by light microscope with 400 times of magnification. The statistical analysis was then performed using oneway Anova & TukeyHSD test. Result: The component active materials consisted of mangosteen peel extract and DFDBBX 2% had the most significant results related to the formation of osteoblasts and osteoclasts. Conclusion: Mangosteen peel extract combined with DFDBBX can increase osteoblasts and decrease osteoclasts in the socket of tooth extraction in Cavia cobaya. The combination of mangosteen peel extract and DFDBBX 2% is the most effective material in increasing osteoblast and decreasing osteoclast.

Cutting blade dentitions in squaliform sharks form by modification of inherited alternate tooth ordering patterns

Science.gov (United States)

Underwood, Charlie; Johanson, Zerina; Smith, Moya Meredith

2016-11-01

The squaliform sharks represent one of the most speciose shark clades. Many adult squaliforms have blade-like teeth, either on both jaws or restricted to the lower jaw, forming a continuous, serrated blade along the jaw margin. These teeth are replaced as a single unit and successor teeth lack the alternate arrangement present in other elasmobranchs. Micro-CT scans of embryos of squaliforms and a related outgroup (Pristiophoridae) revealed that the squaliform dentition pattern represents a highly modified version of tooth replacement seen in other clades. Teeth of Squalus embryos are arranged in an alternate pattern, with successive tooth rows containing additional teeth added proximally. Asynchronous timing of tooth production along the jaw and tooth loss prior to birth cause teeth to align in oblique sets containing teeth from subsequent rows; these become parallel to the jaw margin during ontogeny, so that adult Squalus has functional tooth rows comprising obliquely stacked teeth of consecutive developmental rows. In more strongly heterodont squaliforms, initial embryonic lower teeth develop into the oblique functional sets seen in adult Squalus, with no requirement to form, and subsequently lose, teeth arranged in an initial alternate pattern.

Prevalence of pannus formation after aortic valve replacement: clinical aspects and surgical management.

Science.gov (United States)

Sakamoto, Yoshimasa; Hashimoto, Kazuhiro; Okuyama, Hiroshi; Ishii, Shinichi; Shingo, Taguchi; Kagawa, Hiroshi

2006-01-01

Pannus formation after aortic valve replacement is not common, but obstruction due to chronic pannus is one of the most serious complications of valve replacement. The causes of pannus formation are still unknown and effective preventive methods have not been fully elucidated. We reviewed our clinical experience of all patients who underwent reoperation for prosthetic aortic valve obstruction due to pannus formation between 1973 and 2004. We compared the initial 18-year period of surgery, when the Björk-Shiley tilting-disk valve was used, and the subsequent 13-year period of surgery, when the St. Jude Medical valve was used. Seven of a total of 390 patients (1.8%) required reoperation for prosthetic aortic valve obstruction due to pannus formation. All seven patients were women; four patients underwent resection of the pannus and three patients needed replacement of the valve. The frequency of pannus formation in the early group was 2.4% (6/253), whereas it was 0.73% (1/137) in the late group (P Pannus was localized at the minor orifice of the Björk-Shiley valve in the early group and turbulent transvalvular blood flow was considered to be one of the important factors triggering its growth. We also consider that small bileaflet valves have the possibility of promoting pannus formation and that the implantation of a larger prosthesis can contribute to reducing the occurrence of pannus.

Tooth loss caused by displaced elastic during simple preprosthetic orthodontic treatment

Science.gov (United States)

Dianiskova, Simona; Calzolari, Chiara; Migliorati, Marco; Silvestrini-Biavati, Armando; Isola, Gaetano; Savoldi, Fabio; Dalessandri, Domenico; Paganelli, Corrado

2016-01-01

The use of elastics to close a diastema or correct tooth malpositions can create unintended consequences if not properly controlled. The American Association of Orthodontists recently issued a consumer alert, warning of “a substantial risk for irreparable damage” from a new trend called “do-it-yourself” orthodontics, consisting of patients autonomously using elastics to correct tooth position. The elastics can work their way below the gums and around the roots of the teeth, causing damage to the periodontium and even resulting in tooth loss. The cost of implants to replace these teeth would well exceed the cost of proper orthodontic care. This damage could also occur in a dental office, when a general dentist tries to perform a simplified orthodontic correction of a minor tooth malposition. The present case report describes a case of tooth loss caused by a displaced intraoral elastic, which occurred during a simple preprosthetic orthodontic treatment. PMID:27672645

Endodontic Treatment of an Anomalous Anterior Tooth with the Aid of a 3-dimensional Printed Physical Tooth Model.

Science.gov (United States)

Byun, Chanhee; Kim, Changhwan; Cho, Seungryong; Baek, Seung Hoon; Kim, Gyutae; Kim, Sahng G; Kim, Sun-Young

2015-06-01

Endodontic treatment of tooth formation anomalies is a challenge to clinicians and as such requires a complete understanding of the aberrant root canal anatomy followed by careful root canal disinfection and obturation. Here, we report the use of a 3-dimensional (3D) printed physical tooth model including internal root canal structures for the endodontic treatment of a challenging tooth anomaly. A 12-year-old boy was referred for endodontic treatment of tooth #8. The tooth showed class II mobility with swelling and a sinus tract in the buccal mucosa and periapical radiolucency. The tooth presented a very narrow structure between the crown and root by distal concavity and a severely dilacerated root. Moreover, a perforation site with bleeding and another ditching site were identified around the cervical area in the access cavity. A translucent physical tooth model carrying the information on internal root canal structures was built through a 3-step process: data acquisition by cone-beam computed tomographic scanning, virtual modeling by image processing, and manufacturing by 3D printing. A custom-made guide jig was then fabricated to achieve a safe and precise working path to the root canal. Endodontic procedures including access cavity preparation were performed using the physical tooth model and the guide jig. At the 7-month follow-up, the endodontically treated tooth showed complete periapical healing with no clinical signs and symptoms. This case report describes a novel method of endodontic treatment of an anomalous maxillary central incisor with the aid of a physical tooth model and a custom-made guide jig via 3D printing technique. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Telemedicine consulting in the patient preparation and planning of prosthetic tooth replacement

Directory of Open Access Journals (Sweden)

Mladenović Dragan

2013-01-01

Full Text Available Introduction. In the management of edentulous spaces, there is a permanent need of a dentist-prosthetician in charge to consult other specialists. Modern telemedicine, based on powerful computer and telecomunication systems, offers an adequate answer to these challenges, being able to transfer and obtain clinical data and consultation information over large distances. Using smartphone or a computer, the teleconsultant acces the system, downloads and review the data and photographs and gave suggestions. The system then enables direct, real time contact with the consultant, chat, or directs them to contact each other by phone. Case report. We presented telemedicine consulting in the patient preparation and planning of prosthetic tooth replacement in 3 cases with different teleconsultation requirements: the first case for prosthetic rehabilitation of his upper teeth, the second one for prosthetic management of his partial edentulousness and “a growth on his gums” in the vestibular region of the frontal teeth and the third one for prosthetic management of total edentulousness of her upper jaw. We used the system of telemedicine in dentistry, established at the Faculty of Medicine in Kosovska Mitrovica. The operation was based on the computer application system XPA3 Online, computer networking and mobile smartphone network. All consultations were succefull with no need for further procedures in regional center. Conclusion. The use of a mobile smartphone has brought about the mobility and availability of teleconsultant specialists in an extent never seen before. Prostheticians are thus able to offer better service to their patients and improve the quality of management of partially or totally edentulous patients, especially in rural areas.

The Effects of Irradiation and Calcium-deficient Diet on the Expression of Interleukin-1 during Tooth Formation of Rat Molar

International Nuclear Information System (INIS)

Kim, Il Joong; Hwang, Eui Hwan; Lee, Sang Rae

2000-01-01

To elucidate the effects of the irradiation and calcium-deficient diet on expression of interleukin (IL)-1 during tooth formation of rat molar. The pregnant three-week-old Spague-Dawley rats were used for the study. The control group was non-irradiation/normal diet group, and the experimental groups were irradiation/normal diet group and irradiation/calcium-diet group. The abdomen of the rats on the 9th day of pregnancy were irradiated with single dose of 350 cGy. The rat pups were sacrificed on the 14th day after delivery and the maxillae tooth germs were taken. The specimen were prepared to make sections for light microscopy, and some of tissue sections were stained immunohistochemically with anti-IL-1 antibody. In the irradiation/normal diet group, dental follicle showed fewer blood vessels, mononuclear cells, and fusions of mononuclear cells than in non-irradiation/normal diet group. Alveolar bone showed a few osteoblasts and osteoclasts. Periodontal ligament showed collagen fibers and fibroblasts with irregularity. Weak immunoreactivity for IL-1 was shown in dental follicle, alveolar bone, and periodontal ligament. In the irradiation/calcium-deficient diet group, dental follicle showed sparse cellularity. Alveolar bone showed diminished number of osteoblasts. Periodontal ligament showed irregular collagen fibers and atrophy of cementoblasts and fibroblasts. No immunoreactivity for IL-1 was shown in dental follicle, alveolar bone, and periodontal ligament. Irradiation and calcium-deficient diet seems to cause disturbance of the expression of interleukin-1 during tooth formation of rat molar.

The Effects of Irradiation and Calcium-deficient Diet on the Expression of Interleukin-1 during Tooth Formation of Rat Molar

Energy Technology Data Exchange (ETDEWEB)

Kim, Il Joong; Hwang, Eui Hwan; Lee, Sang Rae [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Kyunghee University, Seoul (Korea, Republic of)

2000-09-15

To elucidate the effects of the irradiation and calcium-deficient diet on expression of interleukin (IL)-1 during tooth formation of rat molar. The pregnant three-week-old Spague-Dawley rats were used for the study. The control group was non-irradiation/normal diet group, and the experimental groups were irradiation/normal diet group and irradiation/calcium-diet group. The abdomen of the rats on the 9th day of pregnancy were irradiated with single dose of 350 cGy. The rat pups were sacrificed on the 14th day after delivery and the maxillae tooth germs were taken. The specimen were prepared to make sections for light microscopy, and some of tissue sections were stained immunohistochemically with anti-IL-1 antibody. In the irradiation/normal diet group, dental follicle showed fewer blood vessels, mononuclear cells, and fusions of mononuclear cells than in non-irradiation/normal diet group. Alveolar bone showed a few osteoblasts and osteoclasts. Periodontal ligament showed collagen fibers and fibroblasts with irregularity. Weak immunoreactivity for IL-1 was shown in dental follicle, alveolar bone, and periodontal ligament. In the irradiation/calcium-deficient diet group, dental follicle showed sparse cellularity. Alveolar bone showed diminished number of osteoblasts. Periodontal ligament showed irregular collagen fibers and atrophy of cementoblasts and fibroblasts. No immunoreactivity for IL-1 was shown in dental follicle, alveolar bone, and periodontal ligament. Irradiation and calcium-deficient diet seems to cause disturbance of the expression of interleukin-1 during tooth formation of rat molar.

Tooth polishing: The current status

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Madhuri Alankar Sawai

2015-01-01

Full Text Available Healthy teeth and gums make a person feel confident and fit. As people go about their daily routines and with different eating and drinking habits, the tooth enamel turns yellowish or gets stained. Polishing traditionally has been associated with the prophylaxis procedure in most dental practices, which patients know and expect. However, with overzealous use of polishing procedure, there is wearing of the superficial tooth structure. This would lead to more accumulation of local deposits. Also, it takes a long time for the formation of the fluoride-rich layer of the tooth again. Hence, now-a-days, polishing is not advised as a part of routine oral prophylaxis procedure but is done selectively based on the patients′ need. The article here, gives an insight on the different aspects of the polishing process along with the different methods and agents used for the same.

Characterization of glycosaminoglycans during tooth development and mineralization in the axolotl, Ambystoma mexicanum.

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Wistuba, J; Völker, W; Ehmcke, J; Clemen, G

2003-10-01

Glycosaminoglycans (GAGs) involved in the formation of the teeth of Ambystoma mexicanum were located and characterized with the cuprolinic blue (CB) staining method and transmission electron microscopy (TEM). Glycosaminoglycan-cuprolinic blue precipitates (GAGCB) were found in different compartments of the mineralizing tissue. Various populations of elongated GAGCB could be discriminated both according to their size and their preferential distribution in the extracellular matrix (ECM). GAGCB populations that differ in their composition could be attributed not only to the compartments of the ECM but also to different zones and to different tooth types (early-larval and transformed). Larger precipitates were only observed within the dentine matrix of the shaft of the early-larval tooth. The composition of the populations differed significantly between the regions of the transformed tooth: pedicel, shaft and dividing zone. In later stages of tooth formation, small-sized GAGCBs were seen as intracellular deposits in the ameloblasts. It is concluded that the composition of GAGCB populations seems to play a role in the mineralization processes during tooth development in A. mexicanum and influence qualitative characteristics of the mineral in different tooth types and zones, and it is suggested that GAGs might be resorbed by the enamel epithelium during the late phase of enamel formation.

Contemporary permanent tooth dimensions, with comparisons to G.V. Black's data.

Science.gov (United States)

Harris, Edward F; Burris, Benjamin G

2003-01-01

The tooth dimensions most commonly cited in the dental literature are those published by the famous restorative dentist G. V. Black late in the 19th century. We report here on the crown dimensions of a large series of contemporary North American Whites and show that Black's values differ significantly from modern values, but not in any consistent or predictable fashion. Black supplied no information about the nature of his sample. We suggest that it may be time to replace Black's data with modern tooth size standards.

A theropod tooth from the Late Triassic of southern Africa

Indian Academy of Sciences (India)

An isolated, large recurved and finely serrated tooth found associated with the prosauropod Euskelosaurus from the Late Triassic part of the Elliot Formation is described here. It is compared to the Triassic thecodonts and carnivorous dinosaurs and its possible affinity is discussed. The tooth possibly belongs to a basal ...

Autotransplantation of Mandibular Third Molar with Buccal Cortical Plate to Replace Vertically Fractured Mandibular Second Molar: A Novel Technique.

Science.gov (United States)

Zufía, Juan; Abella, Francesc; Trebol, Ivan; Gómez-Meda, Ramón

2017-09-01

Tooth replacement often leads to inadequate vertical volume in the recipient site bone when a tooth has been extracted because of a vertical root fracture (VRF). This case report presents the autotransplantation of a mandibular third molar (tooth #32) with the attached buccal cortical plate to replace a mandibular second molar (tooth #31) diagnosed with a VRF. After extraction of tooth #31, the recipient socket was prepared based on the size measured in advance with cone-beam computed tomographic imaging. The precise and calculated osteotomy of the cortical bone of tooth #32 allowed for the exact placement of the donor tooth in the position of tooth #31. The total extraoral time was only 25 minutes. The block was fixed to the recipient socket with an osteosynthesis screw and splinted with a double resin wire for 8 weeks. At the 6-month follow-up, the screw was removed, and the stability of the tooth and the regeneration obtained throughout the vestibular area were confirmed. At the 2-year follow-up, the transplanted tooth was asymptomatic and maintained a normal bone level. Advantages of autotransplantation over dental implants include maintenance of proprioception, possible orthodontic movements, and a relatively low cost. This case report demonstrates that an autotransplantation of a third molar attached to its buccal cortical plate is a viable option to replace teeth with a VRF. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

The functional and palaeoecological implications of tooth morphology and wear for the megaherbivorous dinosaurs from the Dinosaur Park Formation (upper Campanian of Alberta, Canada.

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Jordan C Mallon

Full Text Available Megaherbivorous dinosaurs were exceptionally diverse on the Late Cretaceous island continent of Laramidia, and a growing body of evidence suggests that this diversity was facilitated by dietary niche partitioning. We test this hypothesis using the fossil megaherbivore assemblage from the Dinosaur Park Formation (upper Campanian of Alberta as a model. Comparative tooth morphology and wear, including the first use of quantitative dental microwear analysis in the context of Cretaceous palaeosynecology, are used to infer the mechanical properties of the foods these dinosaurs consumed. The phylliform teeth of ankylosaurs were poorly adapted for habitually processing high-fibre plant matter. Nevertheless, ankylosaur diets were likely more varied than traditionally assumed: the relatively large, bladed teeth of nodosaurids would have been better adapted to processing a tougher, more fibrous diet than the smaller, cusp-like teeth of ankylosaurids. Ankylosaur microwear is characterized by a preponderance of pits and scratches, akin to modern mixed feeders, but offers no support for interspecific dietary differences. The shearing tooth batteries of ceratopsids are much better adapted to high-fibre herbivory, attested by their scratch-dominated microwear signature. There is tentative microwear evidence to suggest differences in the feeding habits of centrosaurines and chasmosaurines, but statistical support is not significant. The tooth batteries of hadrosaurids were capable of both shearing and crushing functions, suggestive of a broad dietary range. Their microwear signal overlaps broadly with that of ankylosaurs, and suggests possible dietary differences between hadrosaurines and lambeosaurines. Tooth wear evidence further indicates that all forms considered here exhibited some degree of masticatory propaliny. Our findings reveal that tooth morphology and wear exhibit different, but complimentary, dietary signals that combine to support the hypothesis

The functional and palaeoecological implications of tooth morphology and wear for the megaherbivorous dinosaurs from the Dinosaur Park Formation (upper Campanian) of Alberta, Canada.

Science.gov (United States)

Mallon, Jordan C; Anderson, Jason S

2014-01-01

Megaherbivorous dinosaurs were exceptionally diverse on the Late Cretaceous island continent of Laramidia, and a growing body of evidence suggests that this diversity was facilitated by dietary niche partitioning. We test this hypothesis using the fossil megaherbivore assemblage from the Dinosaur Park Formation (upper Campanian) of Alberta as a model. Comparative tooth morphology and wear, including the first use of quantitative dental microwear analysis in the context of Cretaceous palaeosynecology, are used to infer the mechanical properties of the foods these dinosaurs consumed. The phylliform teeth of ankylosaurs were poorly adapted for habitually processing high-fibre plant matter. Nevertheless, ankylosaur diets were likely more varied than traditionally assumed: the relatively large, bladed teeth of nodosaurids would have been better adapted to processing a tougher, more fibrous diet than the smaller, cusp-like teeth of ankylosaurids. Ankylosaur microwear is characterized by a preponderance of pits and scratches, akin to modern mixed feeders, but offers no support for interspecific dietary differences. The shearing tooth batteries of ceratopsids are much better adapted to high-fibre herbivory, attested by their scratch-dominated microwear signature. There is tentative microwear evidence to suggest differences in the feeding habits of centrosaurines and chasmosaurines, but statistical support is not significant. The tooth batteries of hadrosaurids were capable of both shearing and crushing functions, suggestive of a broad dietary range. Their microwear signal overlaps broadly with that of ankylosaurs, and suggests possible dietary differences between hadrosaurines and lambeosaurines. Tooth wear evidence further indicates that all forms considered here exhibited some degree of masticatory propaliny. Our findings reveal that tooth morphology and wear exhibit different, but complimentary, dietary signals that combine to support the hypothesis of dietary niche

An in vitro study to compare the accuracy of the master cast fabricated by four different transfer impression techniques for single-tooth implant replacement.

Science.gov (United States)

Lahori, Manesh; Nagrath, Rahul; Agrawal, Prateek

2014-03-01

Single tooth implant retained crowns have become a recognized technique for the replacement of the missing teeth. With the predictable integration of implants, the emphasis is shifted towards precise prosthesis. Minor movement of the impression coping retained inside the impression material can occur during all the procedures, leading to the three-dimensional spatial inaccuracies in the master casts. Therefore, the present study was undertaken with the purpose to evaluate the accuracy of single-tooth implant impression techniques using four different impression copings, so as to obtain a precise definitive cast for a single-unit implant restoration. A maxillary acrylic resin model with a standard single implant in the first molar region was used to simulate a clinical situation. A total of 60 impressions were made with polyvinylsiloxane impression material, which were divided into four groups of 15 impressions each. Group I used non-modified square impression coping, while in group II, III and IV square impression coping were modified differently. Master casts fabricated for all the groups were analyzed to detect rotational position change of the hexagon on the implant replicas in the master casts in reference to the resin model. The master casts obtained with the roughened and adhesive-coated impression copings showed a lower amount of rotational movement than the masters casts achieved with the non-modified impression copings. Hence, the clinician should use sandblasted and adhesive coated impression copings to achieve a more accurate and precise orientation of the implant replicas in the laboratory master casts in single-tooth implant restorations.

Tooth apatite as a bone substitute: an experimental study and clinical applications

International Nuclear Information System (INIS)

Eun-Seok Kim; Pill-Hoon Choung

1999-01-01

The purpose of this study is to evaluate the usefulness of calcined teeth powder as biological apatite. The animal experiment was performed in 36 rabbits aging 6 weeks and weighing 1.6 kg. In experimental group, tooth apatite powder was implanted to 10 mm bony defects in diameter made on the cranial bone of the rabbits. As control groups, synthetic porous hydroxyapatite and resorbable type calcium carbonate were implanted to the defects of same size. Each group was sacrificed in 1, 2, 4, 6, 8, 12 weeks after the surgery. Specimens were prepared for decalcified samples and observed by a light microscope. And we also performed quantitative analysis of new bone formation through image analysis using computer. In clinical applications, we used tooth apatite alone or mixed with decalcified freeze-dried bone for reconstruction of bony defects in 15 patients undergone enucleation of cyst or ameloblastoma. The obtained results were as follows; 1) The powder of the calcined teeth was called as 'tooth apatite' and it seemed to have biocompatibility in rabbits and human. 2) In group of tooth apatite, after 4 weeks of operation, new bone directly bonded to the particles was observed. And in 12 weeks of it, new bone occupied most of the bony defects. In 6 weeks, resorption of the tooth apatite particles was observed. Thus the tooth apatite was regarded as one of resorbable apatite. 3) The group of tooth apatite showed new bone formation similar to the group of porous hydroxyapatite, but they were inferior to the group of resorbable calcium carbonate. 4) In clinical application, tooth apatite had biocompatibility and new bone formation was observed without any complication except for 1 case. So we think it is a useful bone substitute with osteoconductivity

Tooth replacements in young adults with severe hypodontia: Orthodontic space closure, dental implants, and tooth-supported fixed dental prostheses. A follow-up study.

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Hvaring, Christina L; Øgaard, Bjørn; Birkeland, Kari

2016-10-01

Children with severe hypodontia have a substantial impairment of their dental health starting early in life. The purpose of this study was to describe types and locations of substitutes for missing teeth in patients with severe hypodontia and to compare the crown and soft tissue morphologies of orthodontic space closure, dental implants, and tooth-supported fixed dental prostheses for replacing teeth in the anterior region. Fifty patients missing 6 or more teeth and aged 18 years or older (mean age, 25.6 years) took part in a follow-up study. The patients were examined clinically with panoramic radiographs and clinical photographs. Crown and soft tissue variables (mucosal discoloration, crown morphology, color, and papilla index) were compared for orthodontic space closure, dental implant fixtures, and fixed dental prostheses. Dental implants, orthodontic space closure, and retaining deciduous teeth were the most commonly prescribed treatments. Persisting deciduous teeth showed a good survival rate at the follow-up examination. Mucosal discoloration was seen only for implant fixtures and was evident for almost all fixtures in the anterior mandible and two thirds of those in the anterior maxilla. The papilla index scored poorer for both implant fixtures and fixed dental prostheses compared with orthodontic space closure. Dental implants in the anterior region proved to be an inadequate treatment modality in patients with severe hypodontia because of pronounced mucosal discoloration. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Spectrophotometric assessment of tooth bleaching under orthodontic braquets bonded with different materials

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Camila Maria Lima de CASTRO

2017-10-01

Full Text Available Abstract Introduction patients have been submitted to tooth bleaching during orthodontic treatment for aesthetic purposes or to anticipate the replacement of restorations after completion of the treatment. Objective to evaluate the effectiveness of tooth bleaching under orthodontic brackets bonded with different materials. Material and method a hundred bovine enamel blocks were divided into two groups, at-home and in-office tooth bleaching. In-office bleaching was subdivided into five groups (n = 10: HP (control - without brackets; SA(t - brackets bonded with Transbond XT, without bleaching; SA(fm - brackets bonded with Orthodontic Fill Magic, without bleaching; HP(t - brackets bonded with Transbond XT subjected to bleaching; and HP(fm - brackets bonded with Orthodontic Fill Magic subjected to bleaching. At-home bleaching followed the same treatments, only replacing the bleaching agent. Spectrophotometric assessment was used for tooth color determination at three moments: 1 before staining (baseline; 2 after staining; 3 after bonding the brackets and bleaching procedures. Data were submitted to ANOVA and analyzed by Tukey's test (p < 0.05. Result For both types of bleaching, the control group had an effective bleaching action. Groups using Transbond XT presented greater bleaching potential among the groups with orthodontic accessory, but the bleaching action differed from the positive control. Groups using Orthodontic Fill Magic presented no bleaching action, resembling the negative control groups (artificial saliva. Conclusion the orthodontic bracket impaired the effectiveness of the at-home and in-office bleaching treatment, regardless of the resin used for bonding.

Utilization of Teeth Replacement Service Among the Elderly ...

African Journals Online (AJOL)

. However, its utilization by the elderly has not been extensively studied. Aim: To determine the utilization of tooth replacement services among the elderly. Materials and Methods: This was a retrospective study of 440 patients aged 60 years ...

Using a Novel Absolute Ontogenetic Age Determination Technique to Calculate the Timing of Tooth Eruption in the Saber-Toothed Cat, Smilodon fatalis.

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M Aleksander Wysocki

Full Text Available Despite the superb fossil record of the saber-toothed cat, Smilodon fatalis, ontogenetic age determination for this and other ancient species remains a challenge. The present study utilizes a new technique, a combination of data from stable oxygen isotope analyses and micro-computed tomography, to establish the eruption rate for the permanent upper canines in Smilodon fatalis. The results imply an eruption rate of 6.0 millimeters per month, which is similar to a previously published average enamel growth rate of the S. fatalis upper canines (5.8 millimeters per month. Utilizing the upper canine growth rate, the upper canine eruption rate, and a previously published tooth replacement sequence, this study calculates absolute ontogenetic age ranges of tooth development and eruption in S. fatalis. The timing of tooth eruption is compared between S. fatalis and several extant conical-toothed felids, such as the African lion (Panthera leo. Results suggest that the permanent dentition of S. fatalis, except for the upper canines, was fully erupted by 14 to 22 months, and that the upper canines finished erupting at about 34 to 41 months. Based on these developmental age calculations, S. fatalis individuals less than 4 to 7 months of age were not typically preserved at Rancho La Brea. On the whole, S. fatalis appears to have had delayed dental development compared to dental development in similar-sized extant felids. This technique for absolute ontogenetic age determination can be replicated in other ancient species, including non-saber-toothed taxa, as long as the timing of growth initiation and growth rate can be determined for a specific feature, such as a tooth, and that growth period overlaps with the development of the other features under investigation.

Using a Novel Absolute Ontogenetic Age Determination Technique to Calculate the Timing of Tooth Eruption in the Saber-Toothed Cat, Smilodon fatalis.

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Wysocki, M Aleksander; Feranec, Robert S; Tseng, Zhijie Jack; Bjornsson, Christopher S

2015-01-01

Despite the superb fossil record of the saber-toothed cat, Smilodon fatalis, ontogenetic age determination for this and other ancient species remains a challenge. The present study utilizes a new technique, a combination of data from stable oxygen isotope analyses and micro-computed tomography, to establish the eruption rate for the permanent upper canines in Smilodon fatalis. The results imply an eruption rate of 6.0 millimeters per month, which is similar to a previously published average enamel growth rate of the S. fatalis upper canines (5.8 millimeters per month). Utilizing the upper canine growth rate, the upper canine eruption rate, and a previously published tooth replacement sequence, this study calculates absolute ontogenetic age ranges of tooth development and eruption in S. fatalis. The timing of tooth eruption is compared between S. fatalis and several extant conical-toothed felids, such as the African lion (Panthera leo). Results suggest that the permanent dentition of S. fatalis, except for the upper canines, was fully erupted by 14 to 22 months, and that the upper canines finished erupting at about 34 to 41 months. Based on these developmental age calculations, S. fatalis individuals less than 4 to 7 months of age were not typically preserved at Rancho La Brea. On the whole, S. fatalis appears to have had delayed dental development compared to dental development in similar-sized extant felids. This technique for absolute ontogenetic age determination can be replicated in other ancient species, including non-saber-toothed taxa, as long as the timing of growth initiation and growth rate can be determined for a specific feature, such as a tooth, and that growth period overlaps with the development of the other features under investigation.

Sox2 marks epithelial competence to generate teeth in mammals and reptiles

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Juuri, Emma; Jussila, Maria; Seidel, Kerstin; Holmes, Scott; Wu, Ping; Richman, Joy; Heikinheimo, Kristiina; Chuong, Cheng-Ming; Arnold, Katrin; Hochedlinger, Konrad; Klein, Ophir; Michon, Frederic; Thesleff, Irma

2013-01-01

Tooth renewal is initiated from epithelium associated with existing teeth. The development of new teeth requires dental epithelial cells that have competence for tooth formation, but specific marker genes for these cells have not been identified. Here, we analyzed expression patterns of the transcription factor Sox2 in two different modes of successional tooth formation: tooth replacement and serial addition of primary teeth. We observed specific Sox2 expression in the dental lamina that gives rise to successional teeth in mammals with one round of tooth replacement as well as in reptiles with continuous tooth replacement. Sox2 was also expressed in the dental lamina during serial addition of mammalian molars, and genetic lineage tracing indicated that Sox2+ cells of the first molar give rise to the epithelial cell lineages of the second and third molars. Moreover, conditional deletion of Sox2 resulted in hyperplastic epithelium in the forming posterior molars. Our results indicate that the Sox2+ dental epithelium has competence for successional tooth formation and that Sox2 regulates the progenitor state of dental epithelial cells. The findings imply that the function of Sox2 has been conserved during evolution and that tooth replacement and serial addition of primary teeth represent variations of the same developmental process. The expression patterns of Sox2 support the hypothesis that dormant capacity for continuous tooth renewal exists in mammals. PMID:23462476

Enzyme replacement therapy prevents dental defects in a model of hypophosphatasia.

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McKee, M D; Nakano, Y; Masica, D L; Gray, J J; Lemire, I; Heft, R; Whyte, M P; Crine, P; Millán, J L

2011-04-01

Hypophosphatasia (HPP) occurs from loss-of-function mutation in the tissue-non-specific alkaline phosphatase (TNALP) gene, resulting in extracellular pyrophosphate accumulation that inhibits skeletal and dental mineralization. TNALP-null mice (Akp2(-/-)) phenocopy human infantile hypophosphatasia; they develop rickets at 1 week of age, and die before being weaned, having severe skeletal and dental hypomineralization and episodes of apnea and vitamin B(6)-responsive seizures. Delay and defects in dentin mineralization, together with a deficiency in acellular cementum, are characteristic. We report the prevention of these dental abnormalities in Akp2(-/-) mice receiving treatment from birth with daily injections of a mineral-targeting, human TNALP (sALP-FcD(10)). sALP-FcD(10) prevented hypomineralization of alveolar bone, dentin, and cementum as assessed by micro-computed tomography and histology. Osteopontin--a marker of acellular cementum--was immuno-localized along root surfaces, confirming that acellular cementum, typically missing or reduced in Akp2(-/-) mice, formed normally. Our findings provide insight concerning how acellular cementum is formed on tooth surfaces to effect periodontal ligament attachment to retain teeth in their osseous alveolar sockets. Furthermore, they provide evidence that this enzyme-replacement therapy, applied early in post-natal life--where the majority of tooth root development occurs, including acellular cementum formation--could prevent the accelerated tooth loss seen in individuals with HPP.

Treatment of a horizontal root-fractured tooth with decoronation procedure: case report

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Selen Esin Yoldaş

2016-05-01

Full Text Available INTRODUCTION: Early loss of permanent anterior teeth due to trauma can cause esthetic and functional problems for young patients. In such cases, replacement of the missing tooth with traditional approaches is possible; however such approaches will reduce the chance of the patient to receive an esthetic and consistent treatment in the future. CASE REPORT: A 12-year-old male patient referred to our clinic with a history of trauma. Complicated crown fracture in tooth no.11 and horizontal root fracture in tooth no. 21 was detected. Following root canal treatment, tooth no. 11 was restored with a fiber post and a strip crown. To avoid alveolar bone loss due to early tooth extraction, decoronation procedure, an alternative approach, was applied to tooth no. 21. This procedure consisted of leaving the root fragment inside the alveolar socket following the removal of the crown. For the rehabilitation of the missing crown, a partial removable prosthesis was implemented. The patient was recalled in 6., 12. and 18. months. Within the follow-up period, no reduction in the alveolar bone level was seen. No sign of infection was evident. The remaining root fragment kept on resorbing. Tooth no. 11 remained symptom-free as well. The patient is still being followed. CONCLUSION: Decoronation is essentially a treatment choice for preventing alveolar bone loss in ankylosed teeth considered for extraction. In this case report, decoronation was shown to be a suitable alternative also for a fractured, non-ankylosed tooth.

Role of multiple cusps in tooth fracture.

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Barani, Amir; Bush, Mark B; Lawn, Brian R

2014-07-01

The role of multiple cusps in the biomechanics of human molar tooth fracture is analysed. A model with four cusps at the bite surface replaces the single dome structure used in previous simulations. Extended finite element modelling, with provision to embed longitudinal cracks into the enamel walls, enables full analysis of crack propagation from initial extension to final failure. The cracks propagate longitudinally around the enamel side walls from starter cracks placed either at the top surface (radial cracks) or from the tooth base (margin cracks). A feature of the crack evolution is its stability, meaning that extension occurs steadily with increasing applied force. Predictions from the model are validated by comparison with experimental data from earlier publications, in which crack development was followed in situ during occlusal loading of extracted human molars. The results show substantial increase in critical forces to produce longitudinal fractures with number of cuspal contacts, indicating a capacity for an individual tooth to spread the load during mastication. It is argued that explicit critical force equations derived in previous studies remain valid, at the least as a means for comparing the capacity for teeth of different dimensions to sustain high bite forces. Copyright © 2014 Elsevier Ltd. All rights reserved.

Immediate natural tooth pontic: A viable yet temporary prosthetic solution: A patient reported outcome

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Sudhir Bhandari

2012-01-01

Conclusion: The concept of immediate pontic placement is surely a viable treatment option and promises an excellent transient esthetic solution for a lost tooth as well as enables good preparation of the extraction site for future prosthetic replacement.

Effects of carbonated soft drink consumption on orthodontic tooth movements in rats.

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Hossein Agha Aghili

2014-04-01

Full Text Available The aim of this animal study was to evaluate the possible effects of Carbonated Soft Drink consumption on the rate of orthodontic tooth movement in rats.Thirty-six adult male Sprague-Dawley rats were randomly divided into two experimental groups and one control group. In the experimental groups (A&B, the water in the dietary regimen was replaced with soft drinks (Fanta® in group A and Cola® in group B two weeks before placement of orthodontic appliances. Then 5-mm nickel-titanium closed-coil springs were placed between the maxillary right first molars and first incisors under general anesthesia. This regimen continued for two weeks more and animals drank soft drink ad libitum. At the end of the experimental period, the rats were sacrificed, and interproximal tooth movements were measured.The mean amounts of tooth movement were 0.19mm in group A, 0.22mm in group B and 0.37mm in group C. Statistical analysis with analysis of variance (ANOVA test showed significant differences between all groups. The least movement occurred in group A that had received Fanta® drink.CSDs consumption decreases the rate of orthodontic tooth movement. The role of soft drinks in decreasing tooth movement might be related to its effects on bone metabolism.

Postoperative radiation therapy after hip replacement in high-risk patients for development of heterotopic bone formation

International Nuclear Information System (INIS)

Hashem, R.; Rene, N.; Souhami, L.; Tanzer, M.; Evans, M.

2011-01-01

Purpose. - To report the results of postoperative radiation therapy in preventing the development of heterotopic bone formation after hip replacement surgery in high-risk patients. Patients and methods. - Between 1991 and 2007, 44 patients were preventively treated with postoperative RT after total hip replacement. In total, 47 hips were treated. All patients were considered at high risk for developing heterotopic bone formation. Most patients (63.5%) were treated because of a history of severe osteoarthritis or ankylosing spondylitis. All patients were treated with shaped parallel-opposed fields with a single fraction of 7 Gy using 6 or 18 MV photons. Most patients (94%) received radiation therapy within 72 hours postoperative and in only three patients radiation therapy was delivered after 72 hours post-surgery (5-8 days). Results. - Minimum follow-up was 1 year. There were 18 females and 26 males. Median age was 63 years (range: 18-80). Treatments were well tolerated and no acute toxicity was seen post-radiation therapy. Only one of the 47 hips (2%) developed heterotopic bone formation. This patient received postoperative radiation therapy to both hips but only developed heterotopic bone formation in one of them. None of the three patients treated beyond 72 hours failed. To date no late toxicity has been observed. Conclusion. - The use of postoperative radiation therapy was an effective and safe treatment in the prevention of heterotopic bone formation in a high-risk group of patients undergoing total hip replacement. (authors)

Endodontic treatment and esthetic management of a primary double tooth with direct composite using silicone buildup guide

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Vinaya Kumar Kulkarni

2012-01-01

Full Text Available Gemination and fusion are morphological dental anomalies, characterized by the formation of a clinically wide tooth. Gemination occurs when one tooth bud tries to divide, while fusion occurs if two buds unite. The terms double teeth, double formation, conjoined teeth, geminifusion, vicinifusion and dental twinning are often used to describe fusion and gemination. Double teeth are associated with clinical problems such as poor esthetics, spacing problems and caries susceptibility. Management of such cases requires a comprehensive knowledge of the clinical entity as well as the problems associated with it. This report presents a case of primary double tooth in a 6-year-old boy involving maxillary left central incisor. The anomalous tooth was carious and pulpally involved. This was treated conservatively by endodontic treatment and esthetic rehabilitation was done with direct composite restoration using a silicone buildup guide. The treated tooth was followed up until exfoliation.

Replacive sulfide formation in anhydrite chimneys from the Pacmanus hydrothermal field, Papua New Guinea

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Los, Catharina; Bach, Wolfgang; Plümper, Oliver

2016-04-01

Hydrothermal flow within the oceanic crust is an important process for the exchange of energy and mass between the lithosphere, hydrosphere and biosphere. Infiltrated seawater heats up and interacts with wall rock, causing mineral replacement reactions. These play a large role in the formation of ore deposits; at the discharge zone, a hot, acidic and metal-rich potential ore fluid exits the crust. It mixes with seawater and forms chimneys, built up of sulfate minerals such as anhydrite (CaSO4), which are subsequently replaced by sulfide minerals. Sulfide formation is related to fluid pathways, defined by cracks and pores in the sulfate chimney. Over time, these systems might develop into massive sulfide deposits. The big question is then: how is sulfate-sulfide replacement related to the evolution of rock porosity? To address this question, sulfide-bearing anhydrite chimneys from the Pacmanus hydrothermal field (Manus Basin, Papua New Guinea) were studied using X-ray tomography, EMPA, FIB-SEM and -TEM. The apparently massive anhydrite turns out highly porous on the micro scale, with sulfide minerals in anhydrite cleavage planes and along grain boundaries. The size of the sulfide grains relates to the pores they grew into, suggesting a tight coupling between dissolution (porosity generation) and growth of replacive minerals. Some of the sulfide grains are hollow and apparently used the dissolving anhydrite as a substrate to start growth in a pore. Another mode of sulfide development is aggregates of euhedral pyrite cores surrounded by colloform chalcopyrite. This occurrence implies that fluid pathways have remained open for some time to allow several stages of precipitation during fluid evolution. To start the replacement and to keep it going, porosity generation is crucial. Our samples show that dissolution of anhydrite occurred along pathways where fluid could enter, such as cleavage planes and grain boundaries. It appears that fluids ascending within the inner

Tooth anatomy

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... whole tooth. This area is known as the "pulp" of the tooth. The jawbone is attached to ... JC, eds. Robbins and Cotran Pathologic Basis of Disease . 9th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap ...

Can dead man tooth do tell tales? Tooth prints in forensic identification.

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Christopher, Vineetha; Murthy, Sarvani; Ashwinirani, S R; Prasad, Kulkarni; Girish, Suragimath; Vinit, Shashikanth Patil

2017-01-01

We know that teeth trouble us a lot when we are alive, but they last longer for thousands of years even after we are dead. Teeth being the strongest and resistant structure are the most significant tool in forensic investigations. Patterns of enamel rod end on the tooth surface are known as tooth prints. This study is aimed to know whether these tooth prints can become a forensic tool in personal identification such as finger prints. A study has been targeted toward the same. In the present in-vivo study, acetate peel technique has been used to obtain the replica of enamel rod end patterns. Tooth prints of upper first premolars were recorded from 80 individuals after acid etching using cellulose acetate strips. Then, digital images of the tooth prints obtained at two different intervals were subjected to biometric conversion using Verifinger standard software development kit version 6.5 software followed by the use of Automated Fingerprint Identification System (AFIS) software for comparison of the tooth prints. Similarly, each individual's finger prints were also recorded and were subjected to the same software. Further, recordings of AFIS scores obtained from images were statistically analyzed using Cronbach's test. We observed that comparing two tooth prints taken from an individual at two intervals exhibited similarity in many cases, with wavy pattern tooth print being the predominant type. However, the same prints showed dissimilarity when compared with other individuals. We also found that most of the individuals with whorl pattern finger print showed wavy pattern tooth print and few loop type fingerprints showed linear pattern of tooth prints. Further more experiments on both tooth prints and finger prints are required in establishing an individual's identity.

2H Stable Isotope Analysis of Tooth Enamel: A Pilot Study

Science.gov (United States)

Holobinko, Anastasia; Kemp, Helen; Meier-Augenstein, Wolfram; Prowse, Tracy; Ford, Susan

2010-05-01

Stable isotope analysis of biogenic tissues such as tooth enamel and bone mineral has become a well recognized and increasingly important method for determining provenance of human remains, and has been used successfully in bioarchaeological studies as well as forensic investigations (Lee-Thorp, 2008; Meier-Augenstein and Fraser, 2008). Particularly, 18O and 2H stable isotopes are well established proxies as environmental indicators of climate (temperature) and source water and are therefore considered as indicators of geographic life trajectories of animals and humans (Hobson et al., 2004; Schwarcz and Walker, 2006). While methodology for 2H analysis of human hair, fingernails, and bone collagen is currently used to determine geographic origin and identify possible migration patterns, studies involving the analysis of 2H in tooth enamel appear to be nonexistent in the scientific literature. The apparent lack of research in this area is believed to have two main reasons. (1) Compared to the mineral calcium hydroxylapatite Ca10(PO4)6(OH)2, in tooth enamel forming bio-apatite carbonate ions replace some of the hydroxyl ions at a rate of one CO32 replacing two OH, yet published figures for the degree of substitution vary (Wopenka and Pasteris, 2005). (2) Most probably due to the aforementioned no published protocols exist for sample preparation and analytical method to obtain δ2H-values from the hydroxyl fraction of tooth enamel. This dilemma has been addressed through a pilot study to establish feasibility of 2H stable isotope analysis of ground tooth enamel by continuous-flow isotope ratio mass spectrometry (IRMS) coupled on-line to a high-temperature conversion elemental analyzer (TC/EA). An array of archaeological and modern teeth has been analyzed under different experimental conditions, and results from this pilot study are being presented. References: Lee-Thorp, J.A. (2008) Archaeometry, 50, 925-950 Meier-Augenstein, W. and Fraser, I. (2008) Science & Justice

Parathyroid hormone related to bone regeneration in grafted and nongrafted tooth extraction sockets in rats.

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Kuroshima, Shinichiro; Al-Salihi, Zeina; Yamashita, Junro

2013-02-01

The quality and quantity of bone formed in tooth extraction sockets impact implant therapy. Therefore, the establishment of a new approach to enhance bone formation and to minimize bone resorption is important for the success of implant therapy. In this study, we investigated whether intermittent parathyroid hormone (PTH) therapy enhanced bone formation in grafted sockets. Tooth extractions of the maxillary first molars were performed in rats, and the sockets were grafted with xenograft. Intermittent PTH was administered either for 7 days before extractions, for 14 days after extractions, or both. The effect of PTH therapy on bone formation in the grafted sockets was assessed using microcomputed tomography at 14 days after extractions. PTH therapy for 7 days before extractions was not effective to augment bone fill, whereas PTH therapy for 14 days after operation significantly augmented bone formation in the grafted sockets. Intermittent PTH therapy starting right after tooth extractions significantly enhanced bone fill in the grafted sockets, suggesting that PTH therapy can be a strong asset for the success of the ridge preservation procedure.

Impact of Ellagic Acid in Bone Formation after Tooth Extraction: An Experimental Study on Diabetic Rats

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Mazen M. Jamil Al-Obaidi

2014-01-01

Full Text Available Objectives. To estimate the impact of ellagic acid (EA towards healing tooth socket in diabetic animals, after tooth extraction. Methods. Twenty-four Sprague Dawley male rats weighing 250–300 g were selected for this study. All animals were intraperitoneally injected with 45 mg/kg (b.w. of freshly prepared streptozotocin (STZ, to induce diabetic mellitus. Then, the animals were anesthetized, and the upper left central incisor was extracted and the whole extracted sockets were filled with Rosuvastatin (RSV. The rats were separated into three groups, comprising 8 rats each. The first group was considered as normal control group and orally treated with normal saline. The second group was regarded as diabetic control group and orally treated with normal saline, whereas the third group comprised diabetic rats, administrated with EA (50 mg/kg orally. The maxilla tissue stained by eosin and hematoxylin (H&E was used for histological examinations and immunohistochemical technique. Fibroblast growth factor (FGF-2 and alkaline phosphatase (ALP were used to evaluate the healing process in the extracted tooth socket by immunohistochemistry test. Results. The reactions of immunohistochemistry for FGF-2 and ALP presented stronger expression, predominantly in EA treated diabetic rat, than the untreated diabetic rat. Conclusion. These findings suggest that the administration of EA combined with RSV may have accelerated the healing process of the tooth socket of diabetic rats, after tooth extraction.

Differences of isolated dental stem cells dependent on donor age and consequences for autologous tooth replacement.

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Kellner, Manuela; Steindorff, Marina M; Strempel, Jürgen F; Winkel, Andreas; Kühnel, Mark P; Stiesch, Meike

2014-06-01

Autologous therapy via stem cell-based tissue regeneration is an aim to rebuild natural teeth. One option is the use of adult stem cells from the dental pulp (DPSCs), which have been shown to differentiate into several types of tissue in vitro and in vivo, especially into tooth-like structures. DPSCs are mainly isolated from the dental pulp of third molars routinely extracted for orthodontic reasons. Due to the extraction of third molars at various phases of life, DPSCs are isolated at different developmental stages of the tooth. The present study addressed the question whether DPSCs from patients of different ages were similar in their growth characteristics with respect to the stage of tooth development. Therefore DPSCs from third molars of 12-30 year-old patients were extracted, and growth characteristics, e.g. doubling time and maximal cell division potential were analysed. In addition, pulp and hard dental material weight were recorded. Irrespective of the age of patients almost all isolated cells reached 40-60 generations with no correlation between maximal cell division potential and patient age. Cells from patients <22 years showed a significantly faster doubling time than the cells from patients ≥22 years. The age of patients at the time of stem cell isolation is not a crucial factor concerning maximal cell division potential, but does have an impact on the doubling time. However, differences in individuals regarding growth characteristics were more pronounced than age-dependent differences. Copyright © 2014 Elsevier Ltd. All rights reserved.

Tooth wear

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Tušek Ivan

2014-01-01

Full Text Available Tooth wear is the loss of dental hard tissue that was not caused by decay and represents a common clinical problem of modern man. In the etiology of dental hard tissue lesions there are three dominant mechanisms that may act synergistically or separately:friction (friction, which is caused by abrasion of exogenous, or attrition of endogenous origin, chemical dissolution of dental hard tissues caused by erosion, occlusal stress created by compression and flexion and tension that leads to tooth abfraction and microfracture. Wear of tooth surfaces due to the presence of microscopic imperfections of tooth surfaces is clinically manifested as sanding veneers. Tribology, as an interdisciplinary study of the mechanisms of friction, wear and lubrication at the ultrastructural level, has defined a universal model according to which the etiopathogenesis of tooth wear is caused by the following factors: health and diseases of the digestive tract, oral hygiene, eating habits, poor oral habits, bruxism, temporomandibular disorders and iatrogenic factors. Attrition and dental erosion are much more common in children with special needs (Down syndrome. Erosion of teeth usually results from diseases of the digestive tract that lead to gastroesophageal reflux (GER of gastric juice (HCl. There are two basic approaches to the assessment of the degree of wear and dental erosion. Depending on the type of wear (erosion, attrition, abfraction, the amount of calcium that was realised during the erosive attack could be determined qualitatively and quantitatively, or changes in optical properties and hardness of enamel could be recorded, too. Abrasion of teeth (abrasio dentium is the loss of dental hard tissue caused by friction between the teeth and exogenous foreign substance. It is most commonly provoked by prosthetic dentures and bad habits, while its effect depends on the size of abrasive particles and their amount, abrasive particle hardness and hardness of tooth

Conservative treatment of an ankylosed tooth after delayed replantation: a case report.

Science.gov (United States)

Díaz, Jaime Andrés; Sandoval, Hector Paulo; Pineda, Patricia Irene; Junod, Pablo Antonio

2007-10-01

An 8-year-old boy sustained avulsion of his upper right maxillary central incisor and lateral luxation of his upper left maxillary incisors. Subsequently, the upper right maxillary central incisor developed replacement resorption, and both upper left maxillary incisors developed pulpal canal obliteration. In the ankylosed tooth, decoronation procedure was performed, and in the 44-month follow-up period the involved alveolar site showed vertical apposition of bone and continuing replacement resorption. Decoronation is a surgical procedure that allows preservation of the bone volume for the future, avoiding aesthetic disturbances and more aggressive treatments in cases where other therapeutic alternatives are not feasible.

EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2013. Scientific Opinion on the substantiation of a health claim related to “non - fermentable ” carbohydrates and maintenance of tooth mineralisation by decreasing tooth demineralisation pursuant to Article 13(5) of Regulation (EC) No 1924/2006

DEFF Research Database (Denmark)

Tetens, Inge

on the scientific substantiation of a health claim related to Nutriose® which should replace “fermentable carbohydrates” in foods or beverages in order to obtain the claimed effect, i.e. maintenance of tooth mineralisation by reducing tooth demineralisation. From the information provided, the Panel noted......” carbohydrates in foods or beverages in order to obtain the claimed effect. The Panel considers that maintaining tooth mineralisation by reducing tooth demineralisation resulting from acid production in plaque caused by the fermentation of carbohydrates is a beneficial physiological effect. The Panel concludes...... that a cause and effect relationship has been established between the consumption of foods/beverages containing “fermentable” carbohydrates at an exposure frequency of four or more times daily and an increased tooth demineralisation, and that the consumption of foods/beverages containing “non...

Tooth Morphogenesis and FGF4 Expression During Development of Molar Tooth in Three Muroid Rodents: Calomyscus elburzensis (Calomyscidae), Mesocricetus auratus (Cricetidae) and Mus musculus (Muridae).

Science.gov (United States)

Hamidi, Kordiyeh; Darvish, Jamshid; Matin, Maryam M; Javanmard, Athar Sadat; Kilpatrick, C William

2017-12-01

To date, no studies have examined the tooth formation during developmental stages of brush-tailed mice (Calomyscidae) and true hamsters (Cricetidae). Herein, we compared the timing of tooth morphogenesis and FGF4 expression pattern during development of the first lower molar in Goodwin's brush-tailed mouse, Calomyscus elburzensis with two other muroid rodents; the house mouse, Mus musculus (Muridae), model organism for tooth morphogenesis, and the golden hamster, Mesocricetus auratus which shares great similarities in cusp pattern with brush-tailed mice. All three species were bred in captivity and developing embryos were isolated at different embryonic days (E). Histological evaluation of lower molars was performed and spatiotemporal pattern of FGF4 expression was determined by immunohistochemistry. Results indicated that morphogenesis of the tooth cusps starts at the beginning of the cap stage of the first lower molar (E14 in house mouse, about E11.5 in golden hamster and E22 in Goodwin's brush-tailed mouse). During the cap to bell stage (E15 in house mouse, E12 in golden hamster and at about E24 in Goodwin's brush-tailed mouse), a decrease in the expression of FGF4 was observed in the mesenchyme, except for the cusp tips. According to our observations, the developmental process of the first lower molar formation in Goodwin's brush-tailed mouse began much later as compared with the other two species. Despite the differences in the temporal pattern of molar development between these three members of the same superfamily (Muroidea), the correlation in the expression of FGF4 with specific stages of tooth morphogenesis supported its regulatory function. Anat Rec, 300:2138-2149, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Replacing Heavily Damaged Teeth by Third Molar Autotransplantation With the Use of Cone-Beam Computed Tomography and Rapid Prototyping.

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Verweij, Jop P; Anssari Moin, David; Wismeijer, Daniel; van Merkesteyn, J P Richard

2017-09-01

This article describes the autotransplantation of third molars to replace heavily damaged premolars and molars. Specifically, this article reports on the use of preoperative cone-beam computed tomographic planning and 3-dimensional (3D) printed replicas of donor teeth to prepare artificial tooth sockets. In the present case, an 18-year-old patient underwent autotransplantation of 3 third molars to replace 1 premolar and 2 molars that were heavily damaged after trauma. Approximately 1 year after the traumatic incident, autotransplantation with the help of 3D planning and rapid prototyping was performed. The right maxillary third molar replaced the right maxillary first premolar. The 2 mandibular wisdom teeth replaced the left mandibular first and second molars. During the surgical procedure, artificial tooth sockets were prepared with the help of 3D printed donor tooth copies to prevent iatrogenic damage to the actual donor teeth. These replicas of the donor teeth were designed based on the preoperative cone-beam computed tomogram and manufactured with the help of 3D printing techniques. The use of a replica of the donor tooth resulted in a predictable and straightforward procedure, with extra-alveolar times shorter than 2 minutes for all transplantations. The transplanted teeth were placed in infraocclusion and fixed with a suture splint. Postoperative follow-up showed physiologic integration of the transplanted teeth and a successful outcome for all transplants. In conclusion, this technique facilitates a straightforward and predictable procedure for autotransplantation of third molars. The use of printed analogues of the donor teeth decreases the risk of iatrogenic damage and the extra-alveolar time of the transplanted tooth is minimized. This facilitates a successful outcome. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Moessbauer Studies of Stannous Fluoride Reactivity with Synthetic Tooth Enamel - A Model for the Tooth Cavity Protection Actions of Novel Dentifrices

International Nuclear Information System (INIS)

Denes, Georges; Muntasar, Abdualhafeed; Kozak, Kathy M.; Baig, Arif A.; White, Donald J.

2002-01-01

SnF 2 is an important toothpaste ingredient, added for the provision of clinical efficacy for hard and soft tissue diseases and in breath protection. Synthetic calcium hydroxyapatite powders were exposed to liquid supernates (25 w/w% toothpaste water slurries, centrifuged) of Crest Gum Care (registered) (SnF 2 ) dentifrice. One-minute treatments were followed by 3x water washing, centrifugation and lyophilization. Post treatment, powders were analyzed by Moessbauer spectroscopy with 0.5-1 gram of treated apatite powder. Results show that tooth mineral stannous fluoride interactions include: (1) formation of surface reaction products with both Sn(II) and Sn(IV) oxidation states; (2) Sn-F binding on mineral surfaces with no evidence of SnO. The surface binding is, however, not pure Sn-F but contains contributions of other ligands, probably oxygens from surface phosphates or hydroxyl groups. Results also suggest that surface reacted stannous tin is oxidized with time, even when bound as a layer on the tooth surface. This study demonstrates for the first time the presence of Sn-F on tooth enamel post treatment and the contribution of passivation to long term stannous chemistry on tooth surfaces. The study also illustrates the practical applications of the Moessbauer technique.

Hypercementosis and odontogenic epithelial hyperplasia associated with a tooth root remnant mimicking a neoplasm. A case report.

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Zustin, J; Friedrich, R E

2010-01-01

Hypercementosis presents as painless, single or multiple non-neoplastic cementum formation beyond the physiological limits of the tooth. It often occurs in the apical area of the involved tooth following infection, chemical or mechanical trauma. We report on radiographic and histopathological findings in a single case of late intraosseous hypercementosis and odontogenic epithelial hyperplasia associated with a minute apical tooth root remnant years after its extraction, mimicking a tumour.

Mathematical description of tooth flank surface of globoidal worm gear with straight axial tooth profile

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Połowniak, Piotr; Sobolak, Mariusz

2017-12-01

In this article, a mathematical description of tooth flank surface of the globoidal worm and worm wheel generated by the hourglass worm hob with straight tooth axial profile is presented. The kinematic system of globoidal worm gear is shown. The equation of globoid helix and tooth axial profile of worm is derived to determine worm tooth surface. Based on the equation of meshing the contact lines are obtained. The mathematical description of globoidal worm wheel tooth flank is performed on the basis of contact lines and generating the tooth side by the extreme cutting edge of worm hob. The presented mathematical model of tooth flank of TA worm and worm wheel can be used e.g. to analyse the contact pattern of the gear.

Tooth - abnormal colors

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... medlineplus.gov/ency/article/003065.htm Tooth - abnormal colors To use the sharing features on this page, please enable JavaScript. Abnormal tooth color is any color other than white to yellowish- ...

[The effect of osteogenic inducer on healing of tooth extraction sockets].

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Chen, Junliang; Shan, Chuncheng; He, Yun; Xia, Delin

2012-06-01

To study the effect of osteogenic inducer (dexamethasone, beta-sodium glycerophosphate and Vitamin C) carried by gelatin sponge on healing and remodeling of tooth extraction sockets. Fifty rabbits were selected. After extracting the first premolars of bilateral maxillary, the right side tooth extraction sockets were filled with gelatin sponge containing osteogenic inducer as experimental side, tooth extraction sockets on left side were filled with gelatin sponge as control. Every ten rabbits were executed at the end of 1, 2, 4, 8, 12 weeks after tooth extraction. Bone density was measured through digital X-ray images. The specimens were examined by histology. The absorption height of alveolar bone at 12 weeks was measured. X-ray measurement showed that the bone density of experimental side was higher than that of control side at 2, 4, 8, 12 weeks, the difference had statistical significance (Psockets of experimental side was earlier than that in control side. The absorptional height of alveolar bone had significant difference between experimental side and control side (Psockets can promote the healing and new bone formation and prevent from alveolar bone absorption.

Mathematical models for the synthesis and optimization of spiral bevel gear tooth surfaces. [for helicopter transmissions

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Litvin, F. L.; Rahman, P.; Goldrich, R. N.

1982-01-01

The geometry of spiral bevel gears and to their rational design are studied. The nonconjugate tooth surfaces of spiral bevel gears are, in theory, replaced (or approximated) by conjugated tooth surfaces. These surfaces can be generated by two conical surfaces, and by a conical surface and a revolution. Although these conjugated tooth surfaces are simpler than the actual ones, the determination of their principal curvatures and directions is still a complicated problem. Therefore, a new approach, to the solution of these is proposed. Direct relationships between the principal curvatures and directions of the tool surface and those of the generated gear surface are obtained. With the aid of these analytical tools, the Hertzian contact problem for conjugate tooth surfaces can be solved. These results are useful in determining compressive load capacity and surface fatigue life of spiral bevel gears. A general theory of kinematical errors exerted by manufacturing and assembly errors is developed. This theory is used to determine the analytical relationship between gear misalignments and kinematical errors. This is important to the study of noise and vibration in geared systems.

Recurrent pannus formation causing prosthetic aortic valve dysfunction: is excision without valve re-replacement applicable?

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Darwazah, Ahmad K

2012-06-29

Prosthetic valve dysfunction at aortic position is commonly caused by pannus formation. The exact etiology is not known. It arises from ventricular aspect of the prosthesis encroaching its leaflets causing stenosis or it may remain localized causing left ventricular outflow tract obstruction without affecting valve function.The difference in location entails different approaches in management. Such a pathology requires surgical excision of the pannus with or without valve re-replacement.A recurrent pannus was observed in a female patient who needed repeated surgical intervention to excise a localized pannus without re-replacement of a well functioning prosthetic valve.Management of our case presents several questions, whether recurrence of pannus is caused by sparing the prosthetic valve, is it simply an exaggeration of an inflammatory healing process in certain individuals or is it ideal to re-replace the valve despite a well preserved function.

Nasomaxillary hypoplasia with a congenitally missing tooth treated with LeFort II osteotomy, autotransplantation, and nickel-titanium alloy wire.

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Ishida, Takayoshi; Ikemoto, Shigehiro; Ono, Takashi

2015-09-01

In some skeletal Class III adult patients with nasomaxillary hypoplasia, the LeFort I osteotomy provides insufficient correction. This case report describes a 20-year-old woman with a combination of nasomaxillary hypoplasia and a protrusive mandible with a congenitally missing mandibular second premolar. We performed a LeFort II osteotomy for maxillary advancement. Autotransplantation of a tooth was also performed; the donor tooth was used to replace the missing permanent tooth. To increase the chance of success, we applied light continuous force with an improved superelastic nickel-titanium alloy wire technique before extraction and after transplantation. The patient's profile and malocclusion were corrected, and the autotransplanted tooth functioned well. The postero-occlusal relationships were improved, and ideal overbite and overjet relationships were achieved. The methods used in this case represent a remarkable treatment. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Histometric study of socket healing after tooth extraction in rats treated with diclofenac

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Yugoshi Luciana Ibara

2002-01-01

Full Text Available The purpose of the present study was to investigate if diclofenac administration interferes with the time course of alveolar wound healing in rats. Forty-two Wistar rats were used, 21 rats received 10 mg/kg/day of diclofenac one day before and 4 days after extraction of the right maxillary incisors and 21 rats received saline. The animals were sacrificed 7, 14 and 21 days after tooth extraction. Progressive new bone formation and a decrease in the volume fraction of blood clot and connective tissue from 1 to 3 weeks after tooth extraction was quantified using the histometric point-counting method. Diclofenac treatment caused a significant delay in new bone formation in association with an impairment of blood clot remission/organization.

The regulation of tooth morphogenesis is associated with epithelial cell proliferation and the expression of Sonic hedgehog through epithelial-mesenchymal interactions

International Nuclear Information System (INIS)

Ishida, Kentaro; Murofushi, Mayumi; Nakao, Kazuhisa; Morita, Ritsuko; Ogawa, Miho; Tsuji, Takashi

2011-01-01

Research highlights: → Bioengineered teeth regulated the contact area of epithelium and mesenchyme. → The crown width is regulated by the contact area of the epithelium and mesenchyme. → This regulation is associated with cell proliferation and Sonic hedgehog expression. → The cusp number is correlated with the crown width of the bioengineered tooth. → Cell proliferation and Shh expression areas regulate the tooth morphogenesis. -- Abstract: Ectodermal organs, such as the tooth, salivary gland, hair, and mammary gland, develop through reciprocal epithelial-mesenchymal interactions. Tooth morphologies are defined by the crown width and tooth length (macro-morphologies), and by the number and locations of the cusp and roots (micro-morphologies). In our current study, we report that the crown width of a bioengineered molar tooth, which was reconstructed using dissociated epithelial and mesenchymal cells via an organ germ method, can be regulated by the contact area between epithelial and mesenchymal cell layers. We further show that this is associated with cell proliferation and Sonic hedgehog (Shh) expression in the inner enamel epithelium after the germ stage has formed a secondary enamel knot. We also demonstrate that the cusp number is significantly correlated with the crown width of the bioengineered tooth. These findings suggest that the tooth micro-morphology, i.e. the cusp formation, is regulated after the tooth width, or macro-morphology, is determined. These findings also suggest that the spatiotemporal patterning of cell proliferation and the Shh expression areas in the epithelium regulate the crown width and cusp formation of the developing tooth.

Factors influencing patients' choice of treatment for a tooth with ...

African Journals Online (AJOL)

Dental caries is a post eruptive pathologic process of bacterial origin involving the dissolution of dental hard tissues with resultant cavity formation and it may progress to irreversible pulpitis and apical periodontitis. The options for managing involved teeth include pulp therapy and tooth extraction. Despite the high success ...

Recurrent pannus formation causing prosthetic aortic valve dysfunction: Is excision without valve re-replacement applicable?

Directory of Open Access Journals (Sweden)

Darwazah Ahmad K

2012-06-01

Full Text Available Abstract Prosthetic valve dysfunction at aortic position is commonly caused by pannus formation. The exact etiology is not known. It arises from ventricular aspect of the prosthesis encroaching its leaflets causing stenosis or it may remain localized causing left ventricular outflow tract obstruction without affecting valve function. The difference in location entails different approaches in management. Such a pathology requires surgical excision of the pannus with or without valve re-replacement. A recurrent pannus was observed in a female patient who needed repeated surgical intervention to excise a localized pannus without re-replacement of a well functioning prosthetic valve. Management of our case presents several questions, whether recurrence of pannus is caused by sparing the prosthetic valve, is it simply an exaggeration of an inflammatory healing process in certain individuals or is it ideal to re-replace the valve despite a well preserved function.

Resin-bonded restorations: a strategy for managing anterior tooth loss in adolescence.

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Zitzmann, Nicola U; Özcan, Mutlu; Scherrer, Susanne S; Bühler, Julia M; Weiger, Roland; Krastl, Gabriel

2015-04-01

In children or adolescents with anterior tooth loss, space closure with the patient's own teeth should be considered as the first choice to avoid lifelong restorative needs. Thorough diagnostics and treatment planning are required when autotransplantation or orthodontic space closure is considered. If these options are not indicated and a single tooth implant restoration is considered, implant placement should be postponed until adulthood, particularly in young women and in patients with hyperdivergent skeletal growth pattern. A ceramic resin-bonded fixed dental prosthesis with 1 retainer is an excellent treatment solution for the interim period; it may also serve as a long-term restoration, providing that sound enamel structure is present, sufficient framework dimensions have been provided, adhesive cementation techniques have been meticulously applied, and functional contacts of the cantilever pontic avoided. In contrast, a resin-bonded fixed dental prosthesis with a metal framework and retentive preparation is indicated if the palatal enamel structure is compromised, interocclusal clearance is limited, splinting (such as after orthodontic treatment) is required, or more than 1 tooth has to be replaced. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Orthodontic Tooth Movement: A Historic Prospective.

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Will, Leslie A

2016-01-01

The earliest report on orthodontic tooth movement in the English literature was published in 1911. Oppenheim carried out studies on baboons to determine what histologic changes occurred during tooth movement. Reitan and many others carried out research into the nature of tooth movement. The pressure-tension model of tooth movement developed from these studies, whereby the two sides of the tooth responded to forces as if in isolation. A second theory, proposed by Stuteville in 1938, was the hydraulic theory of tooth movement. In this theory, fluid from the vasculature, lymphatic system and intercellular spaces responds to the forces of tooth movement, damping the force and limiting movement. Bien and Baumrind expanded on this theory with their own studies in the 1960s. It is clear that both the pressure-tension and fluid flow concepts have merit, but considerable work needs to be done to ascertain the details so that tooth movement can be managed and controlled. © 2016 S. Karger AG, Basel.

Autotransplantation of Third Molars With Platelet-Rich Plasma for Immediate Replacement of Extracted Non-Restorable Teeth: A Case Series.

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Gonzalez-Ocasio, Jorge; Stevens, Mark

2017-09-01

The aim of this study was to examine the use of platelet-rich plasma (PRP) for autotransplantation of third molars as a successful technique to provide immediate tooth structure for space maintenance and masticatory function when premature loss of a permanent tooth occurs and other dental restorative options are not indicated. This study included 10 healthy patients 10 to 17 years of age with at least 1 immature third molar (one to two thirds of root formation) used to replace extracted non-restorable teeth. Eleven third molars were transplanted and adapted to sockets of the extracted teeth with the adjunct of PRP. Transplanted teeth were stabilized to the adjacent teeth using orthodontic wires and dental composite for 1 month. Patients were followed for 1 year. Function, tooth vitality, root development, and periodontal health were recorded. All 10 patients had functioning asymptomatic transplanted teeth, with physiologic tooth mobility after splint removal at 1 month and after 1 year. All 10 patients had positive tooth vitality (by cold test) at 3, 6, and 12 months; all transplants showed positive root development (average growth, 2.01 mm) confirmed and measured using periapical radiographs. No patients required root canal therapy at any point in the study. Periodontal assessments were performed at the scheduled follow-up appointments with circumferential periodontal probing. Periodontal health was maintained because probing depths were shallower than 4 mm during the 1-year follow-up. Autotransplantation of immature third molars with PRP shows excellent results and should be considered a viable option for premature loss of permanent molars. PRP might have other advantages, such as root promotion and neurosensory development. Published by Elsevier Inc.

Ability of mini-implant-facilitated micro-osteoperforations to accelerate tooth movement in rats.

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Cheung, Tracy; Park, Juyoung; Lee, Deborah; Kim, Catherine; Olson, Jeffrey; Javadi, Shadi; Lawson, Gregory; McCabe, James; Moon, Won; Ting, Kang; Hong, Christine

2016-12-01

Although current techniques for accelerated tooth movement often involve invasive surgical procedures, micro-osteoperforations (MOPs) using mini-implants may facilitate orthodontic tooth movement without raising flaps, reduce surgical risks, and increase patient acceptance. In this study, we evaluated the effectiveness of mini-implant-facilitated MOPs in inducing accelerated tooth movement and investigated the potential risks for root resorption. Five MOPs were placed on the left side around the maxillary first molars in 6 rats using an automated mini-implant driver, whereas the right side received no MOPs as the control. Closed-coiled springs were secured from incisors to first molars for orthodontic tooth movement. Tooth movement was measured, and samples underwent radiologic and histologic analyses. The MOP side exhibited a 1.86-fold increase in the rate of tooth movement with decreased bone density and bone volume around the first molars compared with the control side. Hematoxylin and eosin and tartrate-resistant acid phosphatase analyses showed increased numbers of osteoclasts as well as new bone formation. Three-dimensional volumetric analysis of all 5 roots of the maxillary first molars demonstrated no statistically significant difference in root volumes. Mini-implant-facilitated MOPs accelerated tooth movement without increased risk for root resorption and therefore may become a readily available and efficient treatment option to shorten orthodontic treatment time with improved patient acceptance. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Antagonistic Functions of USAG-1 and RUNX2 during Tooth Development.

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Yumiko Togo

Full Text Available Supernumerary teeth and tooth agenesis are common morphological anomalies in humans. We previously obtained evidence that supernumerary maxillary incisors form as a result of the successive development of the rudimentary maxillary incisor tooth germ in Usag-1 null mice. The development of tooth germs is arrested in Runx2 null mice, and such mice also exhibit lingual epithelial buds associated with the upper molars and incisors. The aim of this study is to investigate the potential crosstalk between Usag-1 and Runx2 during tooth development. In the present study, three interesting phenomena were observed in double null Usag-1-/-/Runx2-/- mice: the prevalence of supernumerary teeth was lower than in Usag-1 null mice; tooth development progressed further compared than in Runx2 null mice; and the frequency of molar lingual buds was lower than in Runx2 null mice. Therefore, we suggest that RUNX2 and USAG-1 act in an antagonistic manner. The lingual bud was completely filled with odontogenic epithelial Sox2-positive cells in the Usag-1+/+/Runx2-/- mice, whereas almost no odontogenic epithelial Sox2-positive cells contributed to supernumerary tooth formation in the rudimentary maxillary incisors of the Usag-1-/-/Runx2+/+ mice. Our findings suggest that RUNX2 directly or indirectly prevents the differentiation and/or proliferation of odontogenic epithelial Sox2-positive cells. We hypothesize that RUNX2 inhibits the bone morphogenetic protein (BMP and/or Wnt signaling pathways regulated by USAG-1, whereas RUNX2 expression is induced by BMP signaling independently of USAG-1.

Awareness, attitudes, need and demand on replacement of missing teeth among a group of partially dentate patients attending a University Dental Hospital.

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Jayasinghe, Rasika Manori; Perera, Janana; Jayasinghe, Vajira; Thilakumara, Indika P; Rasnayaka, Sumudu; Shiraz, Muhammad Hanafi Muhammad; Ranabahu, Indra; Kularatna, Sanjeewa

2017-07-27

Our objective was to assess awareness, attitudes, need and demand on replacement of missing teeth according to edentulous space, age, gender, ethnicity, educational level and socio-economical status of the patient. 76.2% of the study group was opined that the missing teeth should be replaced by prosthetic means. Majority were keen in getting them replaced mainly for the comfort in mastication. Although 77.9 and 32.9% were aware of the removable prostheses and implants respectively, only 25.2% knew about tooth supported bridges as an option of replacement of missing teeth. Participants' awareness on tooth and implant supported prostheses is at a higher level. Participants' opinion on need of regular dental visit was statistically significant when gender, ethnicity and education level were considered. The highest demand for replacement of missing teeth was observed in Kennedy class I and II situations in both upper and lower arches. Demand for fixed prostheses was significantly highest in Kennedy class II in upper and lower arches. In conclusion, although removable prosthodontic options are known to most of the patients, their awareness on tooth and implant supported prostheses is also at a higher level. The highest demand for replacement of missing teeth is by patients with Kennedy class I and II situations whereas Kennedy class II being the category with highest demand for fixed prostheses. We recommend that the location of missing teeth to be considered as a priority when educating patients on the most appropriate prosthetic treatment options. Dentists' involvement in educating patients on prosthetic options needs to be improved.

[Assessment of tooth bleaching efficacy with spectrophotometer].

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Zhu, Wenhao; Liu, Chang; Pan, Jie

2014-06-01

To analyze the changes in CIE L*, a*, and b* at cervical, body, and incisal sites after tooth bleaching by using a spectrophotometer. Sixty-seven intact and healthy maxillary central incisors were in-vestigated. These incisors were darker than A3 according to the Vita Classical shade guide. The CIE tooth shade parameters L*, a*, and b* were simultaneously recorded at three tooth areas (cervical, body, and incisal) with a spectrophotometer before and after tooth bleaching (35%H2O2 coordinating with Beyond whitening accelerator irradiating). The shade dif-ferential (DeltaE) was calculated. ANOVA, paired t-test, and Pearson correlation analysis were used for data analysis. The efficacy rates of tooth bleaching were satisfactory, with 86.6%, 86.6%, and 85.1% in the cervical, body, and incisal sites, respectively. The average values of DeltaE were 5.09, 4.44, and 4.40 in the cervical, body, and incisal sites. Tooth bleaching significantly increased L* and significantly decreased a* and b* in all tooth areas (P spectrophotometer could objectively evaluate the whitening effect of tooth bleaching at the different tooth sites. The tooth bleaching system (35%H202 coordinating with Beyond whitening accelerator irradiating) exerts powerful bleaching actions in most of the tooth areas investigated. The order of tooth bleaching effectiveness is cervicalbody>incisal. Yellow coloration is decreased mainly at the cervical site, and brightness was increased mostly at theincisal site. The effectiveness of tooth bleaching increases as the baseline b* value increases.

Esthetic Reconstruction of Diastema with Adhesive Tooth-Colored Restorations and Hyaluronic Acid Fillers

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Supawadee Naorungroj

2017-01-01

Full Text Available Objective. This report presents a comprehensive esthetic treatment with adhesive tooth-colored restorations in a combination with hyaluronic acid (HA fillers of diastema in an orthodontic patient with relapse. Case Report. A 36-year-old female patient consulted about 1.5–2 mm midline diastema after an orthodontic relapse of replacing missing central incisors with lateral incisors and dark-colored gingival tissue as a result of a metal post and core with porcelain fused to a metal (PFM crown at the left lateral incisor. Restorative treatments included replacing the PFM with all-ceramic material and placing a ceramic veneer on the right lateral incisor. To close the space, crown forms of both lateral incisors were altered. A direct resin composite was then used to reform right and left canines to a more ideal lateral incisor shape. An HA fillers injection was used to fill the remaining open gingival embrasure. Eighteen months after treatment, the interdental papilla remained stable and the patient was satisfied with the result. Conclusion. Esthetic reconstruction of diastema and open gingival embrasure in this case can be accomplished without orthodontic retreatment. Tooth-colored restorations and HA filler injection appear as a promising modality to address this patient’s esthetic concern.

Three dimensional mathematical model of tooth for finite element analysis

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Puškar Tatjana

2010-01-01

Full Text Available Introduction. The mathematical model of the abutment tooth is the starting point of the finite element analysis of stress and deformation of dental structures. The simplest and easiest way is to form a model according to the literature data of dimensions and morphological characteristics of teeth. Our method is based on forming 3D models using standard geometrical forms (objects in programmes for solid modeling. Objective. Forming the mathematical model of abutment of the second upper premolar for finite element analysis of stress and deformation of dental structures. Methods. The abutment tooth has a form of a complex geometric object. It is suitable for modeling in programs for solid modeling SolidWorks. After analyzing the literature data about the morphological characteristics of teeth, we started the modeling dividing the tooth (complex geometric body into simple geometric bodies (cylinder, cone, pyramid,.... Connecting simple geometric bodies together or substricting bodies from the basic body, we formed complex geometric body, tooth. The model is then transferred into Abaqus, a computational programme for finite element analysis. Transferring the data was done by standard file format for transferring 3D models ACIS SAT. Results. Using the programme for solid modeling SolidWorks, we developed three models of abutment of the second maxillary premolar: the model of the intact abutment, the model of the endodontically treated tooth with two remaining cavity walls and the model of the endodontically treated tooth with two remaining walls and inserted post. Conclusion Mathematical models of the abutment made according to the literature data are very similar with the real abutment and the simplifications are minimal. These models enable calculations of stress and deformation of the dental structures. The finite element analysis provides useful information in understanding biomechanical problems and gives guidance for clinical research.

Associations between the number of natural teeth in postmenopausal women and hormone replacement therapy.

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Han, Kyungdo; Ko, Youngkyung; Park, Yong-Gyu; Park, Jun-Beom

2016-12-01

Increasing research suggests that periodontal status is associated with hormone replacement therapy in postmenopausal women. This study was performed to assess the relationship between the number of natural teeth and ever use of hormone replacement therapy in postmenopausal women using nationally representative Korean data. Data from the Korea National Health and Nutrition Examination Survey between 2010 and 2012 were used, and the analysis in this study was confined to a total of 4869 respondents over 19 years old who had gone through menopause and who had no missing data for the reproductive factors and outcome variables in that study. The total number of natural teeth was then calculated after excluding third molars. The time of day when tooth brushing was done was recorded as representative oral health behavior. Multiple logistic regression analyses were used to assess association between the number of natural teeth and the use of hormone replacement therapy. Among participants who had ever used hormone replacement therapy, the proportions (percentage and standard error) with no teeth, 1-9 teeth, 10-19 teeth, 20-27 teeth, and 28 teeth were 5.0±2.4%, 6.7±1.4%, 12.5±1.7%, 18.9±1.0%, and 20.7±1.6%, respectively (Preplacement therapy, after adjustments. The analysis revealed that the use of hormone replacement therapy by postmenopausal women showed positive effects for retention of natural teeth. Lack of hormone replacement therapy may be considered to be an independent risk indicator for tooth loss in Korean postmenopausal women. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Overview of Tooth Disorders

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... teeth using a thin resin cement. Bleaching, or tooth whitening, is a process used by dentists to lighten ... following? Damage to only the hard outer surface (enamel) of the tooth An incomplete fracture of a ...

Dental Caries (Tooth Decay)

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... Materials Contact Us Home Research Data & Statistics Dental Caries (Tooth Decay) Dental caries (tooth decay) remains the most prevalent chronic disease ... adults, even though it is largely preventable. Although caries has significantly decreased for most Americans over the ...

Dental Caries (Tooth Decay)

Science.gov (United States)

... Contact Us Home Research Data & Statistics Share Dental Caries (Tooth Decay) Dental caries (tooth decay) remains the most prevalent chronic disease ... adults, even though it is largely preventable. Although caries has significantly decreased for most Americans over the ...

Effect of rotary cutting instruments on the resin-tooth interfacial ultra structure: An in vivo study.

Science.gov (United States)

Sherawat, Sudhir; Tewari, Sanjay; Duhan, Jigyasa; Gupta, Alpa; Singla, Rakesh

2014-12-01

To evaluate the effect of cutting teeth with different types of burs at various speeds on surface topography of tooth surface and interfacial gap formation at resin-tooth interface. The human molars were divided into seven groups: Diamond bur in airrotor (DA) & micromotor (DM), crosscut carbide bur in airrotor (CCA) & micromotor (CCM), plain carbide bur in airrotor (CA) & micromotor (CM) and #600-grit silicon carbide paper (SiC). In five samples from each group Class II box-only cavities were restored. The occlusal surface of four teeth per group was flattened. Two out of four teeth were acid etched. Teeth were subjected for scanning electron microscopy (SEM). Interfacial gap was observed in all groups with no significant difference. SEM observations revealed CA, CCA & DA were coarser than CM, CCM, DM and SiC. SEM of etched tooth surfaces revealed complete removal of amorphous smear layer in CA & CM, partial removal in CCA, CCM, DA & DM and no removal in SiC. Selecting an appropriate bur and its speed may not play an important role in bonding in terms of interfacial gap formation. Variable changes were observed in surface topography with different burs before and after acid etching. Key words:Surface topography, resin-tooth interface, interfacial gap, bonding.

Direct Resin Composite Restoration of Maxillary Central Incisors with Fractured Tooth Fragment Reattachment: Case Report.

Science.gov (United States)

Szmidt, Monika; Górski, Maciej; Barczak, Katarzyna; Buczkowska-Radlińska, Jadwiga

This article presents a clinical protocol to reconstruct two accidentally damaged maxillary central incisors using composite resin material and a fractured tooth component. A patient was referred to the clinic with fracture of the two maxillary central incisors. Clinical examination revealed that both teeth were fractured in the middle third of the crown and that the fractures involved enamel and dentin with no pulp exposure. The patient had also suffered a lower lip laceration. When the lip was evaluated, a fractured fragment of the maxillary right central incisor was found inside the wound. The missing part of the tooth was replaced via adhesive attachment. Due to the damage of the fractured part of the maxillary left central incisor, direct composite restoration of this tooth was performed. With the advent of adhesive dentistry, the process of fragment reattachment has become simplified and more reliable. This procedure provides improved function, is faster to perform, and provides long-lasting effects, indicating that reattachment of a coronal fragment is a realistic alternative to placement of conventional resin composite restorations.

Fluoridation and tooth wear in Irish adults.

LENUS (Irish Health Repository)

Burke, F M

2010-10-01

The aim of this study was to determine the prevalence of tooth wear in adults in Ireland and its relationship with water fluoridation. The National Survey of Adult Oral Health was conducted in 2000\\/2001. Tooth wear was determined using a partial mouth examination assessing the upper and lower anterior teeth. A total of 2456 subjects were examined. In this survey, increasing levels and severity of tooth wear were associated with ageing. Men were more affected by tooth wear and were more likely to be affected by severe tooth wear than women. It was found that age, and gender were significant predictors of tooth wear (P < 0.01). Overall, there was no significant relationship between fluoridation and tooth wear in this study.

Correlation of natural tooth colour with aging in the Spanish population.

Science.gov (United States)

Gómez Polo, Cristina; Gómez Polo, Miguel; Montero, Javier; Martínez Vazquez De Parga, Juan Antonio; Celemin Viñuela, Alicia

2015-10-01

To analyse natural tooth colour in the Spanish population according to the colour coordinates lightness (L*), chroma (C*), hue (h*), red-green axis (a*) and yellow-blue axis (b*) in order to quantify the correlation and changes of tooth colour with age and sex. Natural tooth colour was measured in a sample of 1,361 Spanish participants of both sexes distributed within an age range of 16 to 89 years. The Easyshade Compact spectrophotometer was used and the CIELAB and CIELCh systems were followed. Pearson's bivariate correlations between age and colour coordinates were highly significant for L* (r=-0.674, P≤0.001), h* (r=-0.468, P≤0.001) and C* (r=0.417, P≤0.001). The correlation between age and colour coordinates was stronger for men than for women, for all colour coordinates. The results showed that C*, b* and a* increased by 0.60, 0.56 and 0.26 units/year on average, respectively, whereas L* and h* decreased progressively with age (by 0.60 units/year, on average), and colour differences increased in a systematic way as the gap between the ages being compared grew wider. The strongest correlation was found between age and L*, then between age and h* (both inverse relationships) and then between age and a*, C* and b* (direct relationships). In addition, a similar degree of change in the colour coordinates L*, C* and h* (of 0.60 units/year on average) was observed for natural tooth colour. Knowledge of the chromatic range of natural teeth may help to choose colour for the replacement of missing elements. © 2015 FDI World Dental Federation.

Immunohistochemical Examination for the Distribution of Podoplanin-Expressing Cells in Developing Mouse Molar Tooth Germs

Science.gov (United States)

Imaizumi, Yuri; Amano, Ikuko; Tsuruga, Eichi; Kojima, Hiroshi; Sawa, Yoshihiko

2010-01-01

We recently reported the expression of podoplanin in the apical bud of adult mouse incisal tooth. This study was aimed to investigate the distribution of podoplanin-expressing cells in mouse tooth germs at several developing stages. At the bud stage podoplanin was expressed in oral mucous epithelia and in a tooth bud. At the cap stage podoplanin was expressed on inner and outer enamel epithelia but not in mesenchymal cells expressing the neural crest stem cell marker nestin. At the early bell stage nestin and podoplanin were expressed in cervical loop and odontoblasts. At the root formation stage both nestin and podoplanin were weakly expressed in odontoblasts generating radicular dentin. Podoplanin expression was also found in the Hertwig epithelial sheath. These results suggest that epithelial cells of developing tooth germ acquire the ability to express nestin, and that tooth germ epithelial cells maintain the ability to express podoplanin in oral mucous epithelia. The expression of podoplanin in odontoblasts was induced as tooth germ development advanced, but was suppressed with the completion of the primary dentin, suggesting that podoplanin may be involved in the cell growth of odontoblasts. Nestin may function as an intermediate filament that binds podoplanin in odontoblasts. PMID:21060740

Pannus Formation Leads to Valve Malfunction in the Tricuspid Position 19 Years after Triple Valve Replacement.

Science.gov (United States)

Alskaf, Ebraham; McConkey, Hannah; Laskar, Nabila; Kardos, Attila

2016-06-20

The Medtronic ATS Open Pivot mechanical valve has been successfully used in heart valve surgery for more than two decades. We present the case of a patient who, 19 years following a tricuspid valve replacement with an ATS prosthesis as part of a triple valve operation following infective endocarditis, developed severe tricuspid regurgitation due to pannus formation.

Investigation of EPR signals on tooth enamel

Energy Technology Data Exchange (ETDEWEB)

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.

Tooth whitening: what we now know.

Science.gov (United States)

Carey, Clifton M

2014-06-01

Current research about tooth whitening shows that it is safe and effective when manufacturer's protocol is followed, yet there are risks of which the profession and users should be aware. This update provides a summary of current research and assessment of the safety and efficacy of tooth whitening regimens. Tooth whitening has become one of the most frequently requested dental procedures by the public. The public has come to demand whiter, more perfect smiles and in response many choices for tooth whitening have been made available. These include home-based products such as toothpastes, gels, and films, as well as in-office based systems where products containing highly concentrated bleaching agents are applied under professional supervision. The profession and public have been aware of certain risks related to tooth whitening such as increased tooth sensitivity and gingival irritation. New research has shown that there are other risks such as tooth surface roughening and softening, increased potential for demineralization, degradation of dental restorations, and unacceptable color change of dental restorations. The new research is also focused on optimizing whitening procedures to reduce tooth sensitivity and to increase the persistence of the whitening. Current reports in the literature are reviewed that are related to the use of peroxide based whitening methods. These reports include in vitro studies for method optimization and mechanism as well as clinical studies on effects of various whitening regimens. When manufacturer's instructions are followed, hydrogen peroxide and carbamide peroxide based tooth whitening is safe and effective. Patients should be informed of the risks associated with tooth whitening and instructed on identification of adverse occurrences so that they may seek professional help as needed. Copyright © 2014 Elsevier Inc. All rights reserved.

Recurrent pannus formation causing prosthetic aortic valve dysfunction: Is excision without valve re-replacement applicable?

OpenAIRE

Darwazah Ahmad K

2012-01-01

Abstract Prosthetic valve dysfunction at aortic position is commonly caused by pannus formation. The exact etiology is not known. It arises from ventricular aspect of the prosthesis encroaching its leaflets causing stenosis or it may remain localized causing left ventricular outflow tract obstruction without affecting valve function. The difference in location entails different approaches in management. Such a pathology requires surgical excision of the pannus with or without valve re-replace...

Cellular and Molecular Changes in Orthodontic Tooth Movement

Science.gov (United States)

Zainal Ariffin, Shahrul Hisham; Yamamoto, Zulham; Zainol Abidin, lntan Zarina; Megat Abdul Wahab, Rohaya; Zainal Ariffin, Zaidah

2011-01-01

Tooth movement induced by orthodontic treatment can cause sequential reactions involving the periodontal tissue and alveolar bone, resulting in the release of numerous substances from the dental tissues and surrounding structures. To better understand the biological processes involved in orthodontic treatment, improve treatment, and reduce adverse side effects, several of these substances have been proposed as biomarkers. Potential biological markers can be collected from different tissue samples, and suitable sampling is important to accurately reflect biological processes. This paper covers the tissue changes that are involved during orthodontic tooth movement such as at compression region (involving osteoblasts), tension region (involving osteoclasts), dental root, and pulp tissues. Besides, the involvement of stem cells and their development towards osteoblasts and osteoclasts during orthodontic treatment have also been explained. Several possible biomarkers representing these biological changes during specific phenomenon, that is, bone remodelling (formation and resorption), inflammation, and root resorption have also been proposed. The knowledge of these biomarkers could be used in accelerating orthodontic treatment. PMID:22125437

Development and microstructure of tooth histotypes in the blue shark, Prionace glauca (Carcharhiniformes: Carcharhinidae) and the great white shark, Carcharodon carcharias (Lamniformes: Lamnidae).

Science.gov (United States)

Moyer, Joshua K; Riccio, Mark L; Bemis, William E

2015-07-01

Elasmobranchs exhibit two distinct arrangements of mineralized tissues in the teeth that are known as orthodont and osteodont histotypes. Traditionally, it has been said that orthodont teeth maintain a pulp cavity throughout tooth development whereas osteodont teeth are filled with osteodentine and lack a pulp cavity when fully developed. We used light microscopy, scanning electron microscopy, and high-resolution micro-computed tomography to compare the structure and development of elasmobranch teeth representing the two histotypes. As an example of the orthodont histotype, we studied teeth of the blue shark, Prionace glauca (Carcharhiniformes: Carcharhinidae). For the osteodont histotype, we studied teeth of the great white shark, Carcharodon carcharias (Lamniformes: Lamnidae). We document similarities and differences in tooth development and the microstructure of tissues in these two species and review the history of definitions and interpretations of elasmobranch tooth histotypes. We discuss a possible correlation between tooth histotype and tooth replacement and review the history of histotype differentiation in sharks. We find that contrary to a long held misconception, there is no orthodentine in the osteodont teeth of C. carcharias. © 2015 Wiley Periodicals, Inc.

Effects of local and whole body irradiation on the appearance of osteoblasts during wound healing in tooth extraction sockets in rats.

Science.gov (United States)

Hosokawa, Yoichiro; Sakakura, Yasunori; Irie, Kazuharu; Kudo, Kohsei; Kashiwakura, Ikuo

2010-01-01

Irradiation before tooth extraction delays wound healing in the alveolar socket. This study examined the influences of local and whole body irradiation before tooth extraction on appearance of osteoblasts in the alveolar bone of rat maxillary first molars because bone formation is observed at the initial phase of wound healing. Several osteoblasts were generated 3 days after tooth extraction, and the number of cells increased day by day. Morphological studies showed there were little differences between local irradiation and non-irradiated controls. In contrast, the extraction wound in the whole body irradiation group showed delayed healing, and there was poor granulation tissue and very few osteoblasts at the bottom of the socket. An ultrastructural study showed that the osteoblasts in the extraction socket of whole body irradiation rats were smaller, and had poorly developed organelles. Injection of bone marrow cells to whole body-irradiated animals immediately after tooth extraction partially restored the number of osteoblasts. New periosteal bone formations outside of sockets showed little delay in the whole body irradiation group. These findings suggest that bone formation in the wound healing of extraction socket requires bone marrow cells from hematopoietic organs such as the bone marrow as well as local sources around the alveolar socket, during the initial phase of wound healing.

Effects of local and whole body irradiation on the appearance of osteoblasts during wound healing in tooth extraction sockets in rats

International Nuclear Information System (INIS)

Hosokawa, Yoichiro; Kudo, Kohsei; Kashiwakura, Ikuo; Sakakura, Yasunori; Irie, Kazuharu

2010-01-01

Irradiation before tooth extraction delays wound healing in the alveolar socket. This study examined the influences of local and whole body irradiation before tooth extraction on appearance of osteoblasts in the alveolar bone of rat maxillary first molars because bone formation is observed at the initial phase of wound healing. Several osteoblasts were generated 3 days after tooth extraction, and the number of cells increased day by day. Morphological studies showed there were little differences between local irradiation and non-irradiated controls. In contrast, the extraction wound in the whole body irradiation group showed delayed healing, and there was poor granulation tissue and very few osteoblasts at the bottom of the socket. An ultrastructural study showed that the osteoblasts in the extraction socket of whole body irradiation rats were smaller, and had poorly developed organelles. Injection of bone marrow cells to whole body-irradiated animals immediately after tooth extraction partially restored the number of osteoblasts. New periosteal bone formations outside of sockets showed little delay in the whole body irradiation group. These findings suggest that bone formation in the wound healing of extraction socket requires bone marrow cells from hematopoietic organs such as the bone marrow as well as local sources around the alveolar socket, during the initial phase of wound healing. (author)

Morphological study of tooth development in podoplanin-deficient mice.

Directory of Open Access Journals (Sweden)

Kenyo Takara

Full Text Available Podoplanin is a mucin-type highly O-glycosylated glycoprotein identified in several somatyic cells: podocytes, alveolar epithelial cells, lymphatic endothelial cells, lymph node stromal fibroblastic reticular cells, osteocytes, odontoblasts, mesothelial cells, glia cells, and others. It has been reported that podoplanin-RhoA interaction induces cytoskeleton relaxation and cell process stretching in fibroblastic cells and osteocytes, and that podoplanin plays a critical role in type I alveolar cell differentiation. It appears that podoplanin plays a number of different roles in contributing to cell functioning and growth by signaling. However, little is known about the functions of podoplanin in the somatic cells of the adult organism because an absence of podoplanin is lethal at birth by the respiratory failure. In this report, we investigated the tooth germ development in podoplanin-knockout mice, and the dentin formation in podoplanin-conditional knockout mice having neural crest-derived cells with deficiency in podoplanin by the Wnt1 promoter and enhancer-driven Cre recombinase: Wnt1-Cre;PdpnΔ/Δmice. In the Wnt1-Cre;PdpnΔ/Δmice, the tooth and alveolar bone showed no morphological abnormalities and grow normally, indicating that podoplanin is not critical in the development of the tooth and bone.

Morphological study of tooth development in podoplanin-deficient mice.

Science.gov (United States)

Takara, Kenyo; Maruo, Naoki; Oka, Kyoko; Kaji, Chiaki; Hatakeyama, Yuji; Sawa, Naruhiko; Kato, Yukinari; Yamashita, Junro; Kojima, Hiroshi; Sawa, Yoshihiko

2017-01-01

Podoplanin is a mucin-type highly O-glycosylated glycoprotein identified in several somatyic cells: podocytes, alveolar epithelial cells, lymphatic endothelial cells, lymph node stromal fibroblastic reticular cells, osteocytes, odontoblasts, mesothelial cells, glia cells, and others. It has been reported that podoplanin-RhoA interaction induces cytoskeleton relaxation and cell process stretching in fibroblastic cells and osteocytes, and that podoplanin plays a critical role in type I alveolar cell differentiation. It appears that podoplanin plays a number of different roles in contributing to cell functioning and growth by signaling. However, little is known about the functions of podoplanin in the somatic cells of the adult organism because an absence of podoplanin is lethal at birth by the respiratory failure. In this report, we investigated the tooth germ development in podoplanin-knockout mice, and the dentin formation in podoplanin-conditional knockout mice having neural crest-derived cells with deficiency in podoplanin by the Wnt1 promoter and enhancer-driven Cre recombinase: Wnt1-Cre;PdpnΔ/Δmice. In the Wnt1-Cre;PdpnΔ/Δmice, the tooth and alveolar bone showed no morphological abnormalities and grow normally, indicating that podoplanin is not critical in the development of the tooth and bone.

Tooth preparations for complete crowns: an art form based on scientific principles.

Science.gov (United States)

Goodacre, C J; Campagni, W V; Aquilino, S A

2001-04-01

No recent literature has reviewed the current scientific knowledge on complete coverage tooth preparations. This article traces the historic evolution of complete coverage tooth preparations and identifies guidelines for scientific tooth preparations. Literature covering 250 years of clinical practice was reviewed with emphasis on scientific data acquired during the last 50 years. Both a MEDLINE search and an extensive manual search were used to locate relevant articles written in English in the last 50 years. Teeth should be prepared so that they exhibit the following characteristics: 10 to 20 degrees of total occlusal convergence, a minimal occlusocervical dimension of 4 mm for molars and 3 mm for other teeth, and an occlusocervical-to-faciolingual dimension ratio of 0.4 or greater. Facioproximal and linguoproximal line angles should be preserved whenever possible. When the above features are missing, the teeth should be modified with auxiliary resistance features such as axial grooves or boxes, preferably on proximal surfaces. Finish line selection should be based on the type of crown/retainer, esthetic requirements, ease of formation, and personal experience. Expectations of enhanced marginal fit with certain finish lines could not be validated by recent research. Esthetic requirements and tooth conditions determine finish line locations relative to the gingiva, with a supragingival location being more acceptable. Line angles should be rounded, and a reasonable degree of surface smoothness is desired. Nine scientific principles have been developed that ensure mechanical, biologic, and esthetic success for tooth preparation of complete coverage restorations.

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

Primary culprit for tooth loss!!

OpenAIRE

Nuvvula, Sailavanya; Chava, Vijay Kumar; Nuvvula, Sivakumar

2016-01-01

Aim: In order to facilitate planning for dental health services and to progress strategies to continue the reduction in tooth loss, it is important to identify the factors that result in such loss. therefore the aim of the study is to investigate the major cause for tooth extraction. Objective: to examine whether the major reason for tooth extraction is dental caries or periodontal disease. Materials and Methods: The study is carried out among the dental practitioners in our district. A quest...

Estradiol replacement enhances fear memory formation, impairs extinction and reduces COMT expression levels in the hippocampus of ovariectomized female mice.

Science.gov (United States)

McDermott, Carmel M; Liu, Dan; Ade, Catherine; Schrader, Laura A

2015-02-01

Females experience depression, posttraumatic stress disorder (PTSD), and anxiety disorders at approximately twice the rate of males, but the mechanisms underlying this difference remain undefined. The effect of sex hormones on neural substrates presents a possible mechanism. We investigated the effect of ovariectomy at two ages, before puberty and in adulthood, and 17β-estradiol (E2) replacement administered chronically in drinking water on anxiety level, fear memory formation, and extinction. Based on previous studies, we hypothesized that estradiol replacement would impair fear memory formation and enhance extinction rate. Females, age 4 weeks and 10 weeks, were divided randomly into 4 groups; sham surgery, OVX, OVX+low E2 (200nM), and OVX+high E2 (1000nM). Chronic treatment with high levels of E2 significantly increased anxiety levels measured in the elevated plus maze. In both age groups, high levels of E2 significantly increased contextual fear memory but had no effect on cued fear memory. In addition, high E2 decreased the rate of extinction in both ages. Finally, catechol-O-methyltransferase (COMT) is important for regulation of catecholamine levels, which play a role in fear memory formation and extinction. COMT expression in the hippocampus was significantly reduced by high E2 replacement, implying increased catecholamine levels in the hippocampus of high E2 mice. These results suggest that estradiol enhanced fear memory formation, and inhibited fear memory extinction, possibly stabilizing the fear memory in female mice. This study has implications for a neurobiological mechanism for PTSD and anxiety disorders. Copyright © 2014 Elsevier Inc. All rights reserved.

RNA-Sequencing Analyses Demonstrate the Involvement of Canonical Transient Receptor Potential Channels in Rat Tooth Germ Development

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Jun Yang

2017-06-01

Full Text Available Tooth development depends on multiple molecular interactions between the dental epithelium and mesenchyme, which are derived from ectodermal and ectomesenchymal cells, respectively. We report on a systematic RNA sequencing analysis of transcriptional expression levels from the bud to hard tissue formation stages of rat tooth germ development. We found that GNAO1, ENO1, EFNB1, CALM1, SIAH2, ATP6V0A1, KDELR2, GTPBP1, POLR2C, SORT1, and members of the canonical transient receptor potential (TRPC channel family are involved in tooth germ development. Furthermore, Cell Counting Kit 8 (CCK8 and Transwell migration assays were performed to explore the effects of these differentially expressed genes (DEGs on the proliferation and migration of dental pulp stem cells. Immunostaining revealed that TRPC channels are expressed at varying levels during odontogenesis. The identified genes represent novel candidates that are likely to be vital for rat tooth germ development. Together, the results provide a valuable resource to elucidate the gene regulatory mechanisms underlying mammalian tooth germ development.

Atypical Odontalgia (Phantom Tooth Pain)

Science.gov (United States)

... atypical facial pain, phantom tooth pain, or neuropathic orofacial pain, is characterized by chronic pain in a tooth ... such as a specialist in oral medicine or orofacial pain. The information contained in this monograph is for ...

Comparative analyses of tooth wear in free-ranging and captive wild equids.

Science.gov (United States)

Taylor, L A; Müller, D W H; Schwitzer, C; Kaiser, T M; Castell, J C; Clauss, M; Schulz-Kornas, E

2016-03-01

Captive breeding has played a crucial role in the conservation of threatened equid species. Grazing ruminants and rhinoceros in captivity have less abrasion-dominated tooth wear than their free-ranging conspecifics, with potential negative consequences for their health. However, a similar study on wild equids in captivity is missing. The aim was to establish if different tooth wear patterns are exhibited by free-ranging and captive equids. Cross-sectional study of museum specimens comparing free-ranging and captive equids. Dental casts of maxillary cheek teeth of 228 museum specimens (122 from free-ranging and 106 from captive individuals) of 7 wild equid species were analysed using the extended mesowear method. Although teeth showing specific abnormalities were not scored, the presence of focal overgrowths (hooks) of the rostral premolars (106, 206) was recorded. Captive Equus ferus przewalskii, E. grevyi, E. hemionus, E. quagga boehmi and E. zebra hartmannae have less abrasion-dominated tooth wear on their premolars than their free-ranging conspecifics (P<0.001). Fewer differences were exhibited between populations in the molars. No differences were exhibited in the distal cusp of the molars (110, 210) between populations, except in a small sample of E. kiang. Captive equids exhibited more homogeneous wear along the tooth row whereas free-ranging equids exhibited a tooth wear gradient, with more abrasion on premolars than molars. There were more rostral hooks on the premolars (106, 206) in the captive than the free-ranging population (P = 0.02). Captive equids did experience less abrasion-dominated tooth wear than their free-ranging conspecifics, but the differences in tooth wear were less pronounced than those between captive and free-ranging wild ruminant and rhinoceros species. This indicates that feeding regimes for captive equids deviate less from natural diets than those for captive ruminants and rhinoceros but that factors leading to hook

Effect of Cytokines on Osteoclast Formation and Bone Resorption during Mechanical Force Loading of the Periodontal Membrane

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Hideki Kitaura

2014-01-01

Full Text Available Mechanical force loading exerts important effects on the skeleton by controlling bone mass and strength. Several in vivo experimental models evaluating the effects of mechanical loading on bone metabolism have been reported. Orthodontic tooth movement is a useful model for understanding the mechanism of bone remodeling induced by mechanical loading. In a mouse model of orthodontic tooth movement, TNF-α was expressed and osteoclasts appeared on the compressed side of the periodontal ligament. In TNF-receptor-deficient mice, there was less tooth movement and osteoclast numbers were lower than in wild-type mice. These results suggest that osteoclast formation and bone resorption caused by loading forces on the periodontal ligament depend on TNF-α. Several cytokines are expressed in the periodontal ligament during orthodontic tooth movement. Studies have found that inflammatory cytokines such as IL-12 and IFN-γ strongly inhibit osteoclast formation and tooth movement. Blocking macrophage colony-stimulating factor by using anti-c-Fms antibody also inhibited osteoclast formation and tooth movement. In this review we describe and discuss the effect of cytokines in the periodontal ligament on osteoclast formation and bone resorption during mechanical force loading.

Autotransplantation donor tooth site harvesting using piezosurgery

OpenAIRE

Ylikontiola, Leena P.; S?ndor, George K.

2016-01-01

Abstract Background: The harvesting of a tooth as a candidate for tooth autotransplantation requires that the delicate dental tissues around the tooth be minimally traumatized. This is especially so for the periradicular tissues of the tooth root and the follicular tissues surrounding the crown. The aim of this report is to describe the use of piezosurgery as an attempt at morbidity reduction in the harvesting of teeth for autotransplantation. Methods: A piezosurgical handpiece and its ...

Dental histology of Coelophysis bauri and the evolution of tooth attachment tissues in early dinosaurs.

Science.gov (United States)

Fong, Raymond K M; LeBlanc, Aaron R H; Berman, David S; Reisz, Robert R

2016-07-01

Studies of dinosaur teeth have focused primarily on external crown morphology and thus, use shed or in situ tooth crowns, and are limited to the enamel and dentine dental tissues. As a result, the full suites of periodontal tissues that attach teeth to the jaws remain poorly documented, particularly in early dinosaurs. These tissues are an integral part of the tooth and thus essential to a more complete understanding of dental anatomy, development, and evolution in dinosaurs. To identify the tooth attachment tissues in early dinosaurs, histological thin sections were prepared from the maxilla and dentary of a partial skull of the early theropod Coelophysis bauri from the Upper Triassic (Rhaetian- 209-201 Ma) Whitaker Quarry, New Mexico, USA. As one of the phylogenetically and geologically oldest dinosaurs, it is an ideal candidate for examining dental tissues near the base of the dinosaurian clade. The teeth of C. bauri exhibited a fibrous tooth attachment in which the teeth possessed five tissues: enamel, dentine, cementum, periodontal ligament (PDL), and alveolar bone. Our findings, coupled with those of more recent studies of ornithischian teeth, indicate that a tripartite periodontium, similar to that of crocodilians and mammals, is the plesiomorphic condition for dinosaurs. The occurrence of a tripartite periodontium in dinosaurs adds to the growing consensus that the presence of these tissues is the plesiomorphic condition for the major amniote clades. Furthermore, this study establishes the relative timing of tissue development and growth directions of periodontal tissues and provides the first comparative framework for future studies of dinosaur periodontal development, tooth replacement, and histology. J. Morphol. 277:916-924, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Proteomic analysis of human tooth pulp: proteomics of human tooth.

Science.gov (United States)

Eckhardt, Adam; Jágr, Michal; Pataridis, Statis; Mikšík, Ivan

2014-12-01

The unique pulp-dentin complex demonstrates strong regenerative potential, which enables it to respond to disease and traumatic injury. Identifying the proteins of the pulp-dentin complex is crucial to understanding the mechanisms of regeneration, tissue calcification, defense processes, and the reparation of dentin by dental pulp. The lack of knowledge of these proteins limits the development of more efficient therapies. The proteomic profile of human tooth pulp was investigated and compared with the proteome of human dentin and blood. The samples of tooth pulp were obtained from 5 sound permanent human third molars of 5 adults (n = 5). The extracted proteins were separated by 2-dimensional gel electrophoresis, analyzed by nano-liquid chromatography tandem mass spectrometry, and identified by correlating mass spectra to the proteomic databases. A total of 342 proteins were identified with high confidence, and 2 proteins were detected for the first time in an actual human sample. The identified tooth pulp proteins have a variety of functions: structural, catalytic, transporter, protease activity, immune response, and many others. In a comparison with dentin and blood plasma, 140 (pulp/dentin) shared proteins were identified, 37 of which were not observed in plasma. It can be suggested that they might participate in the unique pulp-dentin complex. This proteomic investigation of human tooth pulp, together with the previously published study of human dentin, is one of the most comprehensive proteome lists of human teeth to date. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Early Orthodontic Tooth Movement into Regenerative Bony Defects: A Case Report.

Science.gov (United States)

Tsai, Hui-Chen; Yao, Chung-Chen Jane; Wong, Man-Ying

Early orthodontic tooth movement following regenerative surgery is controversial. In this case, during protraction of the maxillary right first premolar to substitute for the long-term missing maxillary right canine, Bio-Oss and Bio-Gide were used for lateral ridge augmentation at the area of the maxillary right lateral incisor and to cover the denuded surface at the buccal side of the first premolar. Orthodontic tooth movement (OTM) commenced 2 weeks after regenerative surgery. After 8 months, new bone formation was observed on the root surface of the first premolar during implant surgery. A cone beam computed tomography scan taken 1.5 years postsurgery revealed good maintenance of regenerative bone at the same site. This satisfactory outcome of early OTM following regenerative surgery suggests biomechanical stimulation may not jeopardize the regenerative effect.

Epithelial Label-Retaining Cells Are Absent during Tooth Cycling in Salmo salar and Polypterus senegalus.

Directory of Open Access Journals (Sweden)

Sam Vandenplas

Full Text Available The Atlantic salmon (Salmo salar and African bichir (Polypterus senegalus are both actinopterygian fish species that continuously replace their teeth without the involvement of a successional dental lamina. Instead, they share the presence of a middle dental epithelium: an epithelial tier enclosed by inner and outer dental epithelium. It has been hypothesized that this tier could functionally substitute for a successional dental lamina and might be a potential niche to house epithelial stem cells involved in tooth cycling. Therefore, in this study we performed a BrdU pulse chase experiment on both species to (1 determine the localization and extent of proliferating cells in the dental epithelial layers, (2 describe cell dynamics and (3 investigate if label-retaining cells are present, suggestive for the putative presence of stem cells. Cells proliferate in the middle dental epithelium, outer dental epithelium and cervical loop at the lingual side of the dental organ to form a new tooth germ. Using long chase times, both in S. salar (eight weeks and P. senegalus (eight weeks and twelve weeks, we could not reveal the presence of label-retaining cells in the dental organ. Immunostaining of P. senegalus dental organs for the transcription factor Sox2, often used as a stem cell marker, labelled cells in the zone of outer dental epithelium which grades into the oral epithelium (ODE transition zone and the inner dental epithelium of a successor only. The location of Sox2 distribution does not provide evidence for epithelial stem cells in the dental organ and, more specifically, in the middle dental epithelium. Comparison of S. salar and P. senegalus reveals shared traits in tooth cycling and thus advances our understanding of the developmental mechanism that ensures lifelong replacement.

DNA Methylation: A Frontier in Tooth Organogenesis and Developmental Dental Defects.

Science.gov (United States)

Wan, Mian; Li, Hongyu; Zhou, Yachuan; Du, Wei; Xu, Xin; Ye, Ling; Zhou, Xuedong; Zheng, Liwei

2018-01-01

Tooth development relies on interactions between epithelial and mesenchymal tissues, which are controlled by sophisticated networks of conserved signaling. The signaling networks regulating odontogenesis have been well characterized, but the epigenetic mechanisms underlying remain to be elucidated. In this review, we describe current researches regarding the control of various genes expression by DNA methylation during odontogenesis, summarize genomic mapping of DNA methylation in various stages of tooth formation and diverse dental tissues by high-throughput approaches, and highlight the roles of DNA methylation in odontogenesis. Researches on mammals have revealed that the genomic methylation, which occurs on cytosine residues, regulates certain genes transcription. Consequently, DNA methylation plays a crucial role in spatiotemporal organization of signaling pathways, and is essential for organogenesis. Recently, mounting evidence proves that methylation of genomes contributes to the spatiotemporal gene dynamics during odontogenesis. With emerging new technologies of mapping cytosine modifications in global genome, investigators are seeking an overall view of DNA methylome dynamics that characterize genetic information to manifest across incredibly varied tooth development stages, dental tissues, and developmental dental defects. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Isolation and characterization of vascular endothelial cells derived from fetal tooth buds of miniature swine.

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Nasu, Masanori; Nakahara, Taka; Tominaga, Noriko; Tamaki, Yuichi; Ide, Yoshiaki; Tachibana, Toshiaki; Ishikawa, Hiroshi

2013-03-01

The aim of the present study was to isolate endothelial cells from tooth buds (unerupted deciduous teeth) of miniature swine. Mandibular molar tooth buds harvested from swine fetuses at fetal days 90-110 were cultured in growth medium supplemented with 15% fetal bovine serum in 100-mm culture dishes until the primary cells outgrown from the tooth buds reached confluence. A morphologically defined set of pavement-shaped primary cells were picked up manually with filter paper containing trypsin/ethylenediamine tetraacetic acid solution and transferred to a separate dish. A characterization of the cellular characteristics and a functional analysis of the cultured cells at passages 3 to 5 were performed using immunofluorescence, a reverse transcriptase polymerase chain reaction assay, a tube formation assay, and transmission electron microscopy. The isolated cells grew in a pavement arrangement and showed the characteristics of contact inhibition upon reaching confluence. The population doubling time was ~48 h at passage 3. As shown by immunocytostaining and western blotting with specific antibodies, the cells produced the endothelial marker proteins such as vascular endothelial cadherin, von Willebrand factor, and vascular endothelial growth factor receptor-2. Observation with time-lapse images showed that small groups of cells aggregated and adhered to each other to form tube-like structures. Moreover, as revealed through transmission electron microscopy, these adherent cells had formed junctional complexes. These endothelial cells from the tooth buds of miniature swine are available as cell lines for studies on tube formation and use in regenerative medical science.

Combined periodontic-orthodonticendodontic interdisciplinary approach in the treatment of periodontally compromised tooth.

Science.gov (United States)

Deepa, D; Mehta, D S; Puri, Viren K; Shetty, Sadashiva

2010-04-01

Orthodontic treatment in adult patients is one of the most frequently encountered components involving multidisciplinary approaches. In the present report, a 28-year-old male patient was treated for localized chronic periodontitis with pocket formation, mobility, pathologic migration and malalignment of maxillary left lateral incisor tooth #22. The periodontal therapy included motivation, education and oral-hygiene instructions (O.H.I.), scaling and root planing and periodontal flap surgery. Subsequently on resolution of periodontal inflammation, orthodontic therapy was carried out using the orthodontic aligner for a period of 6 months. Post-treatment (3 years) results showed complete resolution of infrabony pocket with significant bone fill, reduced tooth mobility and complete alignment of the affected maxillary left lateral incisor, thus restoring the esthetics and function.

Seasonal variation in kangaroo tooth enamel oxygen and carbon isotopes in southern Australia

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Brookman, Tom H.; Ambrose, Stanley H.

2012-09-01

Serial sampling of tooth enamel growth increments for carbon and oxygen isotopic analyses of Macropus (kangaroo) teeth was performed to assess the potential for reconstructing paleoseasonality. The carbon isotope composition of tooth enamel apatite carbonate reflects the proportional intake of C3 and C4 vegetation. The oxygen isotopic composition of enamel reflects that of ingested and metabolic water. Tooth enamel forms sequentially from the tip of the crown to the base, so dietary and environmental changes during the tooth's formation can be detected. δ13C and δ18O values were determined for a series of enamel samples drilled from the 3rd and 4th molars of kangaroos that were collected along a 900 km north-south transect in southern Australia. The serial sampling method did not yield pronounced seasonal isotopic variation patterns in Macropus enamel. The full extent of dietary isotopic variation may be obscured by attenuation of the isotopic signal during enamel mineralisation. Brachydont (low-crowned) Macropus teeth may be less sensitive to seasonal variation in isotopic composition due to time-averaging during mineralisation. However, geographic variations observed suggest that there may be potential for tracking latitudinal shifts in vegetation zones and seasonal environmental patterns in response to climate change.

The effect of factor VIII deficiencies and replacement and bypass therapies on thrombus formation under venous flow conditions in microfluidic and computational models.

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Abimbola A Onasoga-Jarvis

Full Text Available Clinical evidence suggests that individuals with factor VIII (FVIII deficiency (hemophilia A are protected against venous thrombosis, but treatment with recombinant proteins can increase their risk for thrombosis. In this study we examined the dynamics of thrombus formation in individuals with hemophilia A and their response to replacement and bypass therapies under venous flow conditions. Fibrin and platelet accumulation were measured in microfluidic flow assays on a TF-rich surface at a shear rate of 100 s⁻¹. Thrombin generation was calculated with a computational spatial-temporal model of thrombus formation. Mild FVIII deficiencies (5-30% normal levels could support fibrin fiber formation, while severe (1 nM, but too low to support fibrin formation (<10 nM. In the absence of platelets, fibrin formation was not supported even at normal FVIII levels, suggesting platelet adhesion is necessary for fibrin formation. Individuals treated by replacement therapy, recombinant FVIII, showed normalized fibrin formation. Individuals treated with bypass therapy, recombinant FVIIa, had a reduced lag time in fibrin formation, as well as elevated fibrin accumulation compared to healthy controls. Treatment of rFVIIa, but not rFVIII, resulted in significant changes in fibrin dynamics that could lead to a prothrombotic state.

Multiphoton microscopy imaging of developing tooth germs

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Pei-Yu Pan

2014-01-01

Conclusion: In this study, a novel multiphoton microscopy database of images from developing tooth germs in mice was set up. We confirmed that multiphoton laser microscopy is a powerful tool for investigating the development of tooth germ and is worthy for further application in the study of tooth regeneration.

A Radiographic Study of Fused and Geminated Tooth

Energy Technology Data Exchange (ETDEWEB)

Park, Chul Jae; Lee, Sang Rae [Dept. of Oral Radiology, College of Dentistry, Kyunhee University, Seoul (Korea, Republic of)

1990-02-15

The incidence and several characteristic features of fused and geminated teeth were studied radiographically, with full mouth periapical radiogram and pantomogram, in 4201 patients of mixed dentition and 5358 patients of permanent dentition. The obtained results were as follows: 1. The prevalence was revealed to 2.86%, 0.32%, 0.33%, and 0.06% in deciduous fused tooth, permanent fused tooth, deciduous geminated tooth and permanent geminated tooth respectively, and these anomalies were occurred in female more than male. 2. Fused teeth were observed predominantly in lower anterior teeth area, especially in lateral incisor and canine region, and many cases of deciduous geminated tooth were observed in upper central incisor region. 3. Congenital missing rates of succedaneous tooth in deciduous fused teeth were 57.1%, 85.7%, 71.0%, 69.0% in upper right and left central-lateral incisor regions, lower right and left lateral incisor-canine regions, respectively. 4. Prevalence of dental caries was 42.3%, 18.8% and 5.6% in deciduous fused, deciduous geminated and permanent fused tooth, respectively. 5. In classifying of fused and geminated teeth into 9 type, by following appearance such as number of crown, root, pulp chamber and pulp canal of those teeth, it was more favorable that Type I (2 crown, 2 root, 2 pulp chamber, 2 pulp canal) in deciduous fused tooth and Type IX (1 crown, 1 root, 1 pulp chamber, 1 pulp canal) in permanent used tooth, deciduous and permanent geminated tooth.

A Radiographic Study of Fused and Geminated Tooth

International Nuclear Information System (INIS)

Park, Chul Jae; Lee, Sang Rae

1990-01-01

The incidence and several characteristic features of fused and geminated teeth were studied radiographically, with full mouth periapical radiogram and pantomogram, in 4201 patients of mixed dentition and 5358 patients of permanent dentition. The obtained results were as follows: 1. The prevalence was revealed to 2.86%, 0.32%, 0.33%, and 0.06% in deciduous fused tooth, permanent fused tooth, deciduous geminated tooth and permanent geminated tooth respectively, and these anomalies were occurred in female more than male. 2. Fused teeth were observed predominantly in lower anterior teeth area, especially in lateral incisor and canine region, and many cases of deciduous geminated tooth were observed in upper central incisor region. 3. Congenital missing rates of succedaneous tooth in deciduous fused teeth were 57.1%, 85.7%, 71.0%, 69.0% in upper right and left central-lateral incisor regions, lower right and left lateral incisor-canine regions, respectively. 4. Prevalence of dental caries was 42.3%, 18.8% and 5.6% in deciduous fused, deciduous geminated and permanent fused tooth, respectively. 5. In classifying of fused and geminated teeth into 9 type, by following appearance such as number of crown, root, pulp chamber and pulp canal of those teeth, it was more favorable that Type I (2 crown, 2 root, 2 pulp chamber, 2 pulp canal) in deciduous fused tooth and Type IX (1 crown, 1 root, 1 pulp chamber, 1 pulp canal) in permanent used tooth, deciduous and permanent geminated tooth.

Association of tooth brushing behavior with oral hygiene index among students using fixed appliance

Science.gov (United States)

Ria, N.; Eyanoer, P.

2018-03-01

Uses of fixed appliance have become popular recently. The purpose of its use is to correct malposition of teeth in order to normalize the masticatory function and to eliminate the accumulation of food remain between the teeth. These will prevent the formation of caries and any periodontal tissue disease. Fixed appliance patients must routinely maintain their oral hygiene. This study was an analytical survey with cross-sectional design to know the relationship between behavior in tooth brushing of students using thefixed appliance and oral hygiene in Poltekkes Kemenkes Medan. The average of Oral Hygiene Index – Simplified (OHI-S) value of students using fixed appliance (2.68) was still above national target which is ≤2, and there was a relationship between behavior in tooth brushing of students using the fixed appliance and oral hygiene (phygiene and to prevent caries formation and periodontal disease patients using fixed appliances should maintain their dental health.

Acid and Alkaline Phosphatase Levels in GCF during Orthodontic Tooth Movement

Science.gov (United States)

Farahani, Mohammad; Safavi, Seyed Mohammadreza; Dianat, Omid; Khoramian Tusi, Somayeh; Younessian, Farnaz

2015-01-01

Statement of the Problem The present constituents of gingival crevicular fluid (GCF) can reflect the changes occurring in underlying tissues. Considering variety of biologic bone markers, alkaline phosphatase and acid phosphatase have been examined as bone turn over markers in orthodontic tooth movement. Purpose The current study designed in a longitudinal pattern to determine the changes of acid and alkaline phosphatase (ACP & ALP) in GCF during orthodontic tooth movement. Materials and Method An upper canines from twelve patients (mean age: 14±2 years) undergoing extraction orthodontic treatment for distal movement served as the test tooth (DC), and its contralateral (CC) and antagonist (AC) canines were used as controls. The CC was included in orthodontic appliance without orthodontic force; the AC was free from any orthodontic appliance. The GCF around the experimental teeth was harvested from mesial and distal tooth sites immediately before appliance placement (T0), and 14 (T2) and 28 days (T3) after it and ALP and ACP concentration were determined spectrophotometrically. Results ALP concentration was elevated significantly in DC and CC groups at days 14 and 28 compared with the AC. In DC group, the ALP was significantly greater in mesial sites than distal site, while no significant changes were found between both sites of CC. The peak level of ALP was observed in mesial sites of DC at T2. Regarding ACP, significant elevation of this enzyme was seen in DC group both in mesial and distal sites at T2 and T3. The peak level of this enzyme was seen at T2. Conclusion Monitoring simultaneous changes of ALP and ACP levels in GCF can reflect the tissue responses occur in periodontium during bone formation and bone resorption during orthodontic tooth movement, respectively. PMID:26535403

Relative tooth size at birth in primates: Life history correlates.

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Smith, Timothy D; Muchlinski, Magdalena N; Bucher, Wade R; Vinyard, Christopher J; Bonar, Christopher J; Evans, Sian; Williams, Lawrence E; DeLeon, Valerie B

2017-11-01

Dental eruption schedules have been closely linked to life history variables. Here we examine a sample of 50 perinatal primates (28 species) to determine whether life history traits correlate with relative tooth size at birth. Newborn primates were studied using serial histological sectioning. Volumes of deciduous premolars (dp 2 -dp 4 ), replacement teeth (if any), and permanent molars (M 1-2/3 ) of the upper jaw were measured and residuals from cranial length were calculated with least squares regressions to obtain relative dental volumes (RDVs). Relative dental volumes of deciduous or permanent teeth have an unclear relationship with relative neonatal mass in all primates. Relative palatal length (RPL), used as a proxy for midfacial size, is significantly, positively correlated with larger deciduous and permanent postcanine teeth. However, when strepsirrhines alone are examined, larger RPL is correlated with smaller RDV of permanent teeth. In the full sample, RDVs of deciduous premolars are significantly negatively correlated with relative gestation length (RGL), but have no clear relationship with relative weaning age. RDVs of molars lack a clear relationship with RGL; later weaning is associated with larger molar RDV, although correlations are not significant. When strepsirrhines alone are analyzed, clearer trends are present: longer gestations or later weaning are associated with smaller deciduous and larger permanent postcanine teeth (only gestational length correlations are significant). Our results indicate a broad trend that primates with the shortest RGLs precociously develop deciduous teeth; in strepsirrhines, the opposite trend is seen for permanent molars. Anthropoids delay growth of permanent teeth, while strepsirrhines with short RGLs are growing replacement teeth concurrently. A comparison of neonatal volumes with existing information on extent of cusp mineralization indicates that growth of tooth germs and cusp mineralization may be selected for

Analysis of tooth tissues using Raman spectroscopy

International Nuclear Information System (INIS)

Timchenko, E.V.; Timchenko, P.E.; Kulabukhova, A.Yu.; Volova, L.T.; Rosenbaum, A.Yu.

2016-01-01

The results of experimental studies of healthy tooth tissue and tooth tissues during caries disease are presented. Features of Raman spectrum of tooth tissues during caries disease are obtained: the main changes are detected at wavenumbers 956 cm -1 .1069 cm -1 . corresponding to phosphates. and 1241 cm -1 . 1660 cm -1 . corresponding to collagen III and collagen I. respectively. Were introduced criteria allowing to detect caries and to identify weakening of tooth tissues. preceding the caries. The reliability of research results is confirmed by scanning electron microscopy. (paper)

Primary culprit for tooth loss!!

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Sailavanya Nuvvula

2016-01-01

Full Text Available Aim: In order to facilitate planning for dental health services and to progress strategies to continue the reduction in tooth loss, it is important to identify the factors that result in such loss. therefore the aim of the study is to investigate the major cause for tooth extraction. Objective: to examine whether the major reason for tooth extraction is dental caries or periodontal disease. Materials and Methods: The study is carried out among the dental practitioners in our district. A questionnaire containing 10 items was distributed to the dental practitioners, which included age, gender, no of teeth indicated for extraction, the reason for extraction, and the periodontal parameters that are involved with the extracted tooth and were requested to complete the form on every extraction they were to undertake. the study form was collected at the end of the study period and data was subjected to statistical analysis. Results: A total of 502 patients were enrolled during the study period, and a total of 1055 teeth were extracted for several reasons. we found that 51.14%extractions are due to dental caries in case of 20-30years age groups, which is more when compared to tooth loss due to periodontal diseases in this age group. whereas in case of >40years of age group periodontal diseases account for 54.11%, and dental caries accounts for only 29.11%. Showing more teeth were lost due to periodontal disease. Conclusion: therefore we concluded that, caries is the dominant reason for extraction in patients with 20–30 years of age while periodontal disease accounts for the majority of tooth extraction in patients older than 40 years.

Tooth wear and wear investigations in dentistry.

Science.gov (United States)

Lee, A; He, L H; Lyons, K; Swain, M V

2012-03-01

Tooth wear has been recognised as a major problem in dentistry. Epidemiological studies have reported an increasing prevalence of tooth wear and general dental practitioners see a greater number of patients seeking treatment with worn dentition. Although the dental literature contains numerous publications related to management and rehabilitation of tooth wear of varying aetiologies, our understanding of the aetiology and pathogenesis of tooth wear is still limited. The wear behaviour of dental biomaterials has also been extensively researched to improve our understanding of the underlying mechanisms and for the development of restorative materials with good wear resistance. The complex nature of tooth wear indicates challenges for conducting in vitro and in vivo wear investigations and a clear correlation between in vitro and in vivo data has not been established. The objective was to critically review the peer reviewed English-language literature pertaining to prevalence and aetiology of tooth wear and wear investigations in dentistry identified through a Medline search engine combined with hand-searching of the relevant literature, covering the period between 1960 and 2011. © 2011 Blackwell Publishing Ltd.

Regenerative Endodontic Treatment with Orthodontic Treatment in a Tooth with Dens Evaginatus: A Case Report with a 4-year Follow-up.

Science.gov (United States)

Natera, Marianella; Mukherjee, Padma M

2018-06-01

Dens evaginatus is a developmental tooth anomaly in which an extra cusp or tubercle protrudes on the occlusal surface of the tooth along with some pulpal tissue. Because of the fragile nature of the protrusion, these teeth are often at risk of pulpal exposure. When this occurs in an immature tooth, regenerative endodontic treatment may be a good treatment approach to promote root formation. There is limited literature that documents the occurrence of orthodontic treatment in teeth that have undergone regenerative endodontic therapy using triple antibiotic paste. Here we present a case of an immature premolar tooth with dens evaginatus that was diagnosed with pulp necrosis and chronic apical abscess. The tooth was treated with regenerative endodontic treatment; after which, the patient received orthodontic treatment with fixed appliances for 2 years. The tooth responded favorably to the regenerative endodontic treatment and orthodontic tooth movement. Clinically and radiographically, all the follow-up examinations revealed an asymptomatic tooth with evidence of periapical healing with stunted root development. The tooth remained asymptomatic even after 4 years. The regenerative endodontic procedure (REP) was successful in treating an immature permanent premolar with pulp necrosis and apical periodontitis with dens evaginatus. In this case, the tooth treated with an REP responded to orthodontic treatment similar to the nonendodontically treated teeth. Further studies are recommended to clarify the precise effects of orthodontic treatment on teeth treated with an REP. Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Is tooth wear in the primary dentition predictive of tooth wear in the permanent dentition? Report from a longitudinal study.

LENUS (Irish Health Repository)

Harding, M A

2010-03-01

To determine the prevalence of tooth wear in the permanent dentition of a sample of 12-year-old school children and establish whether an association exists between tooth wear recorded now and tooth wear recorded in their primary dentition at age five.

The adsorption of peptides and purified salivary proteins onto tooth enamel. A study on pellicle formation

NARCIS (Netherlands)

Juriaanse, Adriaan Cornelis

1980-01-01

The most common diseases that occur in the oral cavity are dental decay (caries) and inflammation of the soft tissues surrounding the teeth (periodontal disease). Both caries and periodontal disease are caused by bacterial metabolites in the plaque, an organic layer on the tooth surface, which

Accelerated tooth eruption in children with diabetes mellitus.

Science.gov (United States)

Lal, Shantanu; Cheng, Bin; Kaplan, Selma; Softness, Barney; Greenberg, Ellen; Goland, Robin S; Lalla, Evanthia; Lamster, Ira B

2008-05-01

The objective of this study was to evaluate tooth eruption in 6- to 14-year-old children with diabetes mellitus. Tooth eruption status was assessed for 270 children with diabetes and 320 control children without diabetes. Data on important diabetes-related variables were collected. Analyses were performed using logistic regression models. Children with diabetes exhibited accelerated tooth eruption in the late mixed dentition period (10-14 years of age) compared to healthy children. For both case patients and control subjects the odds of a tooth being in an advanced eruptive stage were significantly higher among girls than boys. There was also a trend associating gingival inflammation with expedited tooth eruption in both groups. No association was found between the odds of a tooth being in an advanced stage of eruption and hemoglobin A(1c) or duration of diabetes. Patients with higher body mass index percentile demonstrated statistically higher odds for accelerated tooth eruption, but the association was not clinically significant. Children with diabetes exhibit accelerated tooth eruption. Future studies need to ascertain the role of such aberrations in dental development and complications such as malocclusion, impaired oral hygiene, and periodontal disease. The standards of care for children with diabetes should include screening and referral programs aimed at oral health promotion and disease prevention.

Functional aspects of treatment with implant-supported single crowns: a quality control study in subjects with tooth agenesis

DEFF Research Database (Denmark)

Goshima, Kenichi; Lexner, Michala O; Thomsen, Carsten Eckhart

2010-01-01

-Related Quality of Life (OHRQoL) in subjects with tooth agenesis. MATERIAL AND METHODS: In nine females and nine males (32 + or - 10 years) with agenesis treated with one to four ISSC (68% in the premolar region), the treatment effect and masticatory function were assessed. The evaluation was performed first...... after implant placement shortly before crown cementation, and again 1 month after cementation. It consisted of questionnaires [including Oral Health Impact Profile (OHIP-49)] and functional examination with plastic strips, the Dental Prescale Film and the Occluzer system, Xylitol color-changeable gum...... with ISSCs in subjects with tooth agenesis significantly increased masticatory function subjectively and clinically as well as OHRQoL. However, as the functional parameters before replacement of the teeth corresponded to values in subjects with complete dentitions, the functional importance of the increase...

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

Role of stretch therapy in comprehensive physical habilitation of patients with Charcot–Marie–Tooth hereditary neuropathy

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N. A. Shnayder

2015-01-01

Full Text Available Charcot–Marie–Tooth hereditary neuropathy (Charcot–Marie–Tooth disease, CMT is the most common form of hereditary neuropathies, accompanied by sensory disorders, progressive muscle weakness with the formation of disabling contractures of the limbs. Currently, the main treatment program is effective CMT habilitation, which can prevent the development of limb deformities and thereby improve the life quality of the patient. Stretch therapy is one of the most effective methods of prevention and treatment of contractures in patients with CMT. This article provides a brief review of the literature regarding the use of stretching as physical therapy program of CMT habilitation.

Combined periodontic-orthodontic-endodontic interdisciplinary approach in the treatment of periodontally compromised tooth

Directory of Open Access Journals (Sweden)

Deepa D

2010-01-01

Full Text Available Orthodontic treatment in adult patients is one of the most frequently encountered components involving multidisciplinary approaches. In the present report, a 28-year-old male patient was treated for localized chronic periodontitis with pocket formation, mobility, pathologic migration and malalignment of maxillary left lateral incisor tooth #22. The periodontal therapy included motivation, education and oral-hygiene instructions (O.H.I., scaling and root planing and periodontal flap surgery. Subsequently on resolution of periodontal inflammation, orthodontic therapy was carried out using the orthodontic aligner for a period of 6 months. Post-treatment (3 years results showed complete resolution of infrabony pocket with significant bone fill, reduced tooth mobility and complete alignment of the affected maxillary left lateral incisor, thus restoring the esthetics and function.

Biologically Based Restorative Management of Tooth Wear

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Martin G. D. Kelleher

2012-01-01

Full Text Available The prevalence and severity of tooth wear is increasing in industrialised nations. Yet, there is no high-level evidence to support or refute any therapeutic intervention. In the absence of such evidence, many currently prevailing management strategies for tooth wear may be failing in their duty of care to first and foremost improve the oral health of patients with this disease. This paper promotes biologically sound approaches to the management of tooth wear on the basis of current best evidence of the aetiology and clinical features of this disease. The relative risks and benefits of the varying approaches to managing tooth wear are discussed with reference to long-term follow-up studies. Using reference to ethical standards such as “The Daughter Test”, this paper presents case reports of patients with moderate-to-severe levels of tooth wear managed in line with these biologically sound principles.

Tooth loss prevalence among cardiac males and females

International Nuclear Information System (INIS)

Bokhari, S.A.H.; Khan, A.A.; Butt, A.K.

2007-01-01

Objective of study was to observe differences of tooth loss prevalence in males and females with Cardiac diseases Poor oral health, tooth loss and periodontal diseases have been reported to be associated with coronary heart diseases. Studies report gender differences in prevalence of cardiac diseases and tooth loss. This paper presents gender differences of tooth loss in cardiac patients of a cardiac hospital of Lahore, Pakistan. Methodology: Age matched Cardiac males and females attending OPD of the Punjab Institute of Cardiology (PIC), Lahore were included in the study. Personal and health-related information were questioned and noted. Oral examination was performed for recording of missing teeth. 1200 CHD study subjects with age-range of 30 to 80 years were enrolled for study. 1045 age matched, 766 (73.30%) males and 279 (26.70%) females were examined for tooth loss. 852 (81.53%) genders had at least one tooth missing. 599 (78.19) males and 253 (90.68%) females were observed with mean tooth loss of 7.5 (SD 8.720) and 11.15 (SD 10.375)respectively statistical association among them was also significant (P= 0.000) with OR of 2.339. More subjects (76.29%) showed a loss of 1-15 teeth that I was also significant among males and females. Tooth loss was significant in age groups of 41-50 years (P=0.001) and 51-60 years (P=0.000) Gender differences of tooth loss prevalence among CHD Subjects were significant with more risk for males as compared to females. (author)

Functional constraints on tooth morphology in carnivorous mammals

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Smits Peter D

2012-08-01

Full Text Available Abstract Background The range of potential morphologies resulting from evolution is limited by complex interacting processes, ranging from development to function. Quantifying these interactions is important for understanding adaptation and convergent evolution. Using three-dimensional reconstructions of carnivoran and dasyuromorph tooth rows, we compared statistical models of the relationship between tooth row shape and the opposing tooth row, a static feature, as well as measures of mandibular motion during chewing (occlusion, which are kinetic features. This is a new approach to quantifying functional integration because we use measures of movement and displacement, such as the amount the mandible translates laterally during occlusion, as opposed to conventional morphological measures, such as mandible length and geometric landmarks. By sampling two distantly related groups of ecologically similar mammals, we study carnivorous mammals in general rather than a specific group of mammals. Results Statistical model comparisons demonstrate that the best performing models always include some measure of mandibular motion, indicating that functional and statistical models of tooth shape as purely a function of the opposing tooth row are too simple and that increased model complexity provides a better understanding of tooth form. The predictors of the best performing models always included the opposing tooth row shape and a relative linear measure of mandibular motion. Conclusions Our results provide quantitative support of long-standing hypotheses of tooth row shape as being influenced by mandibular motion in addition to the opposing tooth row. Additionally, this study illustrates the utility and necessity of including kinetic features in analyses of morphological integration.

Use of ultrasound Doppler to determine tooth vitality in a discolored tooth after traumatic injury: its prospects and limitations

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Yong-Wook Cho

2014-02-01

Full Text Available When a tooth shows discoloration and does not respond to the cold test or electric pulp test (EPT after a traumatic injury, its diagnosis can be even more difficult due to the lack of proper diagnostic methods to evaluate its vitality. In these case reports, we hope to demonstrate that ultrasound Doppler might be successfully used to evaluate the vitality of the tooth after trauma, and help reduce unnecessary endodontic treatments. In all three of the present cases, the teeth were discolored after traumatic injuries and showed negative responses to the cold test and EPT. However, they showed distinctive vital reactions in the ultrasound Doppler test during the whole observation period. In the first case, the tooth color returned to normal, and the tooth showed a positive response to the cold test and EPT at 10 wk after the injury. In the second case, the tooth color had returned to its normal shade at 10 wk after the traumatic injury but remained insensitive to the cold test and EPT. In the third case, the discoloration was successfully treated with vital tooth bleaching.

Tooth Retained Implant: No More an Oxymoron

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Divya Bhat

2011-03-01

Full Text Available Introduction: Periodontally af-fected teeth are treated in one of the two ways. (1 Tooth retention after periodontal surgery, in which the degree of regeneration achieved is unpredictable. (2 Tooth extrac-tion and implant placement. Implants have an osseointegrated surface which does not provide adequate shock absorption. Regeneration can be achieved by resecting the crown of the affected tooth and submerging the root. This technique has not had a clinical application so far as the tooth becomes difficult to restore. Placing an implant within the root can make the retained root restorable. At the same time, as the implant is placed within the root surface it achieves a periodontal integration which dampens occlusal forces better than osseointegration. Therefore, such a “tooth retained implant” may serve as an additional treatment option with significant benefits over tooth retention and implant placement alone. The hypothesis: Implants placed within retained roots have shown cementum deposition and attachment of periodontal ligament fibers over their surface. This periodontal attachment may be able to dam-pen forces better than in an osseointegrated implant. Moreover, since an implant is being placed, the crown of the tooth can be resected and submerged. This prevents epithelial migration, allows for the periodontal ligament cells to populate the wound and favors regeneration.Evaluation of the hypothesis: The technique of placing implants within cavities prepared in the root and then submerging them are simple for any practitioner placing implants routinely.

Histochemical demonstration of activity of acid phosphatase and beta-glucuronidase in bovine incisor tooth germs

DEFF Research Database (Denmark)

Kirkeby, S; Salling, E; Moe, D

1983-01-01

. After initiation of enamel formation, a change in localization and intensity of the colored reaction product was observed in the ameloblasts. The activity appeared stronger and was restricted to a narrow zone just apical to the nucleus. It is proposed that the acid hydrolases in the tooth forming cells...

Disturbances in Tooth Mineralization and Forensic Dental Age Estimations

DEFF Research Database (Denmark)

Jensen, Niels Dyrgaard; Arge, Sára Oladóttir; Larsen, Sara Tangmose

When performing a forensic dental age assessment, mineralization disturbances of the teeth and the possible consequences these may have upon the reliability of the assessment must be taken into consideration. Furthermore, mineralization disturbances of a general character in the teeth may be seen...... as an indicator of more systemic insults during tooth formation and thus supplement the examination performed by the forensic pathologist. At our department the forensic dental age assessment is based upon a dental panoramic image, intra oral images of the third molars as well as a clinical photograph...

In vitro tooth whitening effect of two medicated chewing gums compared to a whitening gum and saliva

Directory of Open Access Journals (Sweden)

Saroea Geoffrey

2008-08-01

Full Text Available Abstract Background Extrinsic staining of teeth may result from the deposition of a variety of pigments into or onto the tooth surface, which originate mainly from diet or from tobacco use. More recently, clinical studies have demonstrated the efficacy of some chewing gums in removing extrinsic tooth staining. The aim of this study was to assess the effectiveness of two nicotine medicated chewing gums (A and B on stain removal in an in vitro experiment, when compared with a confectionary whitening chewing gum (C and human saliva (D. Methods Bovine incisors were stained by alternating air exposure and immersion in a broth containing natural pigments such as coffee, tea and oral microorganisms for 10 days. Stained enamel samples were exposed to saliva alone or to the test chewing gums under conditions simulating human mastication. The coloration change of the enamel samples was measured using a spectrophotometer. Measurements were obtained for each specimen (average of three absorbances using the L*a*b scale: lightness (L*, red-green (a and yellow-blue (b. Results Medicated chewing gums (A and B removed a greater amount of visible extrinsic stain, while the confectionary chewing gum with a whitening claim (C had a milder whitening effect as evaluated by quantitative and qualitative assessment. Conclusion The tested Nicotine Replacement Therapy (NRT chewing gums were more effective in the removal of the extrinsic tooth stain. This visible improvement in tooth whitening appearance could strengthen the smokers' motivation to quit smoking.

21 CFR 872.3580 - Preformed gold denture tooth.

Science.gov (United States)

2010-04-01

... tooth in a fixed or removable partial denture. (b) Classification. Class I (general controls). The... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Preformed gold denture tooth. 872.3580 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a...

Rapid and selective removal of composite from tooth surfaces with a 9.3 µm CO2 laser using spectral feedback.

Science.gov (United States)

Chan, Kenneth H; Hirasuna, Krista; Fried, Daniel

2011-09-01

Dental composite restorative materials are color matched to the tooth and are difficult to remove by mechanical means without excessive removal or damage to peripheral enamel and dentin. Lasers are ideally suited for selective ablation to minimize healthy tissue loss when replacing existing restorations, sealants, or removing composite adhesives such as residual composite left after debonding orthodontic brackets. In this study, a carbon dioxide laser operating at 9.3-µm with a pulse duration of 10-20-microsecond and a pulse repetition rate of ∼200 Hz was integrated with a galvanometer based scanner and used to selectively remove composite from tooth surfaces. Spectra of the plume emission were acquired after each laser pulse and used to differentiate between the ablation of dental enamel or composite. Microthermocouples were used to monitor the temperature rise in the pulp chamber during composite removal. The composite was placed on tooth buccal and occlusal surfaces and the carbon dioxide laser beam was scanned across the surface to selectively remove the composite without excessive damage to the underlying sound enamel. The residual composite and the damage to the underlying enamel was evaluated using optical microscopy. The laser was able to rapidly remove composite from tooth buccal and occlusal surfaces with minimal damage to the underlying sound enamel and without excessive heat accumulation in the tooth. This study demonstrated that composite can be selectively removed from tooth surfaces at clinically relevant rates using a CO(2) laser operating at 9.3-µm with high pulse repetition rates with minimal heat deposition and damage to the underlying enamel. Copyright © 2011 Wiley-Liss, Inc.

[Pannus Formation Six-years after Aortic and Mitral Valve Replacement with Tissue Valves;Report of a Case].

Science.gov (United States)

Nakamura, Makoto; Muraoka, Arata; Aizawa, Kei; Akutsu, Hirohiko; Kurumisawa, Soki; Misawa, Yoshio

2015-07-01

A 77-year-old man presented with exertional dyspnea. He had undergone aortic and mitral valve replacement with tissue valves 6-years earlier. The patient's hemoglobin level was 9.8 g/dl and serum aspartate aminotransferase (70 mU/ml) and lactate dehydrogenase (1,112 mU/ml) were elevated. Echocardiography revealed stenosis of the prosthetic valve in the aortic position with peak flow velocity of 3.8 m/second and massive mitral regurgitation. The patient underwent repeat valve replacement. Pannus formation around both implanted valves was observed. The aortic valve orifice was narrowed by the pannus, and one cusp of the prosthesis in the mitral position was fixed and caused the regurgitation, but they were free from cusp laceration or calcification. The patient's postoperative course was uneventful, and he continues to do well 14 months after surgery.

21 CFR 872.5525 - Preformed tooth positioner.

Science.gov (United States)

2010-04-01

...) MEDICAL DEVICES DENTAL DEVICES Therapeutic Devices § 872.5525 Preformed tooth positioner. (a) Identification. A preformed tooth positioner is a plastic device that is an impression of a perfected bite...

Remineralising efficacy of tooth mousse plus (ACP CCPF) on radiated tooth

International Nuclear Information System (INIS)

Priya; Hegde, Mithra N.; Hegde, Nidarsh D.; Suchetha Kumari, N.; Sanjeev, Ganesh

2016-01-01

Dental complication is the common problem faced all over the world. Subjects with poor oral hygiene and patients undergoing radiotherapy for oral cancers are developing signs of decalcification of enamel, lesions and Caries. A well designed treatment is necessary to safeguard the tooth enamel surface before and after radiation, only then the caries on the enamel surface can be arrested by re-hardening it and ultimately converting them to the normal healthy condition. To determine the Annealing effect of radiated tooth by testing maximum micro hardness of the teeth before and after 30 days of radiation by the application of Remineralising agents. In our study, we collected 30 intact caries free human molar teeth and were sectioned mesio-distally

Parameters affecting tooth loss during periodontal maintenance in a Greek population.

Science.gov (United States)

Tsami, Alexandra; Pepelassi, Eudoxie; Kodovazenitis, George; Komboli, Mado

2009-09-01

Investigators have evaluated predictive parameters of tooth loss during the maintenance phase (MP). The authors conducted a retrospective study to evaluate the rate of tooth loss and to explore the parameters that affect tooth loss during MP in a Greek population. A periodontist administered periodontal treatment and maintenance care to 280 participants with severe periodontitis for a mean period +/- standard deviation of 10.84 +/- 2.13 years. The periodontist recorded the following parameters for each participant: oral hygiene index level, simplified gingival index level, clinical attachment level, probing depth measurements, initial tooth prognosis, smoking status, tooth loss during active periodontal treatment and MP, and compliance with suggested maintenance visits. The authors found that total tooth loss during active treatment (n = 1,427) was greater than during MP (n = 918) and was associated with the initial tooth prognosis, tooth type group, participants' compliance with suggested maintenance visits, smoking status and acceptability of the quality of tooth restorations. Most of the teeth extracted during maintenance had an initial guarded prognosis (n = 612). Participants whose compliance was erratic had a greater risk of undergoing tooth extraction than did participants whose compliance was complete. Participants' initial tooth prognosis, tooth type, compliance with suggested maintenance visits and smoking status affected tooth loss during MP. Initial guarded prognosis and erratic compliance increased the risk of undergoing tooth extraction during maintenance. Determining predictive parameters for disease progression and tooth loss provides critical information to clinicians so that they can develop and implement rational treatment planning.

Combined periodontic-orthodonticendodontic interdisciplinary approach in the treatment of periodontally compromised tooth

OpenAIRE

Deepa, D; Mehta, D. S.; Puri, Viren K.; Shetty, Sadashiva

2010-01-01

Orthodontic treatment in adult patients is one of the most frequently encountered components involving multidisciplinary approaches. In the present report, a 28-year-old male patient was treated for localized chronic periodontitis with pocket formation, mobility, pathologic migration and malalignment of maxillary left lateral incisor tooth #22. The periodontal therapy included motivation, education and oral-hygiene instructions (O.H.I.), scaling and root planing and periodontal flap surgery. ...

Variables affecting orthodontic tooth movement with clear aligners.

Science.gov (United States)

Chisari, Justin R; McGorray, Susan P; Nair, Madhu; Wheeler, Timothy T

2014-04-01

In this study, we examined the impacts of age, sex, root length, bone levels, and bone quality on orthodontic tooth movement. Clear aligners were programmed to move 1 central incisor 1 mm over the course of 8 weeks. Thirty subjects, ages 19 to 64, were enrolled, and measurements were made on digital models (percentage of tooth movement goal achieved). Morphometric features and bone quality were assessed with cone-beam computed tomography. Data from this study were combined with data from 2 similar studies to increase the power for some analyses. The mean percentage of tooth movement goal achieved was 57% overall. Linear regression modeling indicated a cubic relationship between age and tooth movement, with a decreasing rate of movement from ages 18 to 35 years, a slightly increasing rate from ages 35 to 50, and a decreasing rate from ages 50 to 70. The final decreasing trend was not apparent for women. As would be expected, the correlation was significant between the percentage of the goal achieved and the cone-beam computed tomography superimposed linear measures of tooth movement. A significant negative correlation was found between tooth movement and the measurement apex to the center of rotation, but bone quality, as measured by fractal dimension, was not correlated with movement. The relationship between age and tooth movement is complex and might differ for male and female patients. Limited correlations with cone-beam computed tomography morphology and rate of tooth movement were detected. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Tooth resorption in cats: contribution of vitamin D and inflammation

NARCIS (Netherlands)

Vrieling, H.E.

2010-01-01

Tooth resorption in cats Tooth resorption affecting several teeth is a painful disease with a prevalence of up to 75% in household cats and is often accompanied by periodontitis. Tooth resorption is caused by an increased number and activity of tooth-resorbing odontoclasts, cells that share

Tooth fractures in canine clinical practice

International Nuclear Information System (INIS)

Capik, I.; Ledecky, V.; Sevcik, A.

2001-01-01

Tooth fractures constitute a considerable fraction of all tooth diseases. Out of the 5,370 dogs treated during four years, 492 were presented with dental problems and 28.3 % of the latter were treated for tooth fractures. Canines were the most frequently affected teeth (38.8 %), followed by premolars (33.1 %), incisors (25.9 %), and molars (2.2 %), 55.4 % of the patients with canine and incisor fractures being large breed dogs. Fractures of premolars (mostly of 108, 208) were divided evenly irrespective of breed or body size. Nonsurgical endodontic treatment yielded good therapeutic results in most cases, but repeated treatment was necessary in some patients

A study on the effects of electron beam irradiation on tooth extraction wound healing in rats

International Nuclear Information System (INIS)

Suzuki, Akiyoshi

1983-01-01

The wound of the upper jaw 3 days after the first molar tooth extraction in female rats was exposed to 1,500 rads (Group 2) and 2,000 rads (Group 3) of the 10 MeV electron beams, and its pathohistological changes were compared with those of rats with the tooth extraction alone (control group). In the control group, the tooth extraction wound was covered with epithelium 10 days later and new bones were formed 17 days later. Wound healing with the epithelium was seen in all irradiated rats 24 days later. The formation of the new teeth was seen 24 days later in the Group 2 and 38 days later in Group 3. Cell infiltration under the epithelial layers was still observed in some of the Group 3, although the wound was covered with epithelium, and the new bone covering the extraction wound was formed 38 days later. Healing was prolonged in Group 3, as compared with that in Group 2. (Namekawa, K.)

Fatigue resistance of 2 different CAD/CAM glass-ceramic materials used for single-tooth implant crowns.

Science.gov (United States)

Çavuşoğlu, Yeliz; Sahin, Erdal; Gürbüz, Riza; Akça, Kivanç

2011-10-01

To evaluate the fatigue resistance of 2 different CAD/CAM in-office monoceramic materials with single-tooth implant-supported crowns in functional area. A metal experimental model with a dental implant was designed to receive in-office CAD/CAM-generated monoceramic crowns. Laterally positioned axial dynamic loading of 300 N at 2 Hz was applied to implant-supported crowns machined from 2 different glass materials for 100,000 cycle. Failures in terms of fracture, crack formation, and chipping were macroscopically recorded and microscopically evaluated. Four of 10 aluminasilicate glass-ceramic crowns fractured at early loading cycles, the rest completed loading with a visible crack formation. Crack formation was recorded for 2 of 10 leucite glass-ceramic crowns. Others completed test without visible damage but fractured upon removal. Lack in chemical adhesion between titanium abutment and dental cement likely reduces the fatigue resistance of machinable glass-ceramic materials. However, relatively better fractural strength of leucite glass-ceramics could be taken into consideration. Accordingly, progress on developmental changes in filler composition of glass-ceramics may be promising. Machinable glass-ceramics do not possess sufficient fatigue resistance for single-tooth implant crowns in functional area.

Spatiotemporal expression of caveolin-1 and EMMPRIN during mouse tooth development.

Science.gov (United States)

Shi, Lu; Li, Lingyun; Wang, Ding; Li, Shu; Chen, Zhi; An, Zhengwen

2016-06-01

Caveolin-1 is a scaffolding protein involved in the formation of cholesterol-rich caveolae lipid rafts within the plasma membrane and is capable of collecting signaling molecules into the caveolae and regulating their activity, including extracellular matrix metalloproteinase inducer (EMMPRIN). However, detailed expression patterns of caveolin-1 and EMMPRIN in the developing dental germ are largely unknown. The present study investigated the expression patterns of caveolin-1 and EMMPRIN in the developing mouse tooth germ by immunohistochemistry and real-time polymerase chain reaction. At the bud stage, caveolin-1 expression was initiated in the epithelium bud and mesenchymal cells, while EMMPRIN was weakly expressed at this stage. At the cap stage, caveolin-1 protein was located in the lingual part of the tooth germ; however, EMMPRIN protein was located in the labial part. From the bell stage to 2 days postnatal, caveolin-1 expression was detected in the ameloblasts and cervical loop area; with EMMPRIN expression in the ameloblasts and odontoblasts. Real-time polymerase chain reaction results showed that both caveolin-1 and EMMPRIN mRNA levels increased gradually with progression of developmental stages, and peaked at day two postnatal. The current finding suggests that both caveolin-1 and EMMPRIN take part in mouse tooth development, especially in the differentiation and organization of odontogenic tissues.

Ion microprobe U-Pb dating of a dinosaur tooth

International Nuclear Information System (INIS)

Sano, Yuji; Terada, Kentaro; Ly, Chi V.; Park, Eun Ju

2006-01-01

Ion microprobe U-Pb dating of apatite is applied to a fossil tooth of a Allosaurid derived from the Hasandong Formation in the Gyeongsang basin, southeastern Korea. Twelve spots on a single fragment of the fossil dentine yield a Tera-Wasserburg concordia intercept age of 115±10 Ma (2σ, MSWD=0.59) on a 238 U/ 206 Pb- 207 Pb/ 206 Pb- 204 Pb/ 206 Pb diagram. The age provides a constraint on the depositional age of the fossil in its host Hassandong Formation as Early Aptian. The success of the ion microprobe dating depends on the heterogeneities of diagenetically incorporated U and Pb at the few hundred μm scale, the consequent variations in Pb isotopic compositions due to radioactive decay and the closed-system behavior of U and Pb. There are at least three end-members to explain the variations of minor chemical components such as FeO, SiO 2 and Al 2 O 3 , and trace elements as Th, U and rare earth elements (REE) in the sample by a simple mixing model. They are (1) very low minor and REE, very high common Pb with variable U abundances, (2) low common Pb, high minor, REE, and U abundances, and (3) low minor, common Pb, and U with intermediate REE abundances, even though groups (2) and (3) may consist of a larger group. Various contributions of the three (and/or two) end-members during diagenetic processes may cause the elemental fractionation of U and Pb in a fossil tooth. (author)

Tooth cusp sharpness as a dietary correlate in great apes.

Science.gov (United States)

Berthaume, Michael A

2014-02-01

Mammalian molars have undergone heavy scrutiny to determine correlates between morphology and diet. Here, the relationship between one aspect of occlusal morphology, tooth cusp radius of curvature (RoC), and two broad dietary categories, folivory and frugivory, is analyzed in apes. The author hypothesizes that there is a relationship between tooth cusp RoC and diet, and that folivores have sharper teeth than frugivores, and further test the correlation between tooth cusp RoC and tooth cusp size. Eight measures of tooth cusp RoC (two RoCs per cusp) were taken from 53 M(2) s from four species and subspecies of frugivorous apes (Pongo pygmaeus, Pan troglodytes troglodytes, Pan troglodytes schweinfurthii, and Gorilla gorilla gorilla) and two subspecies of folivorous apes (Gorilla beringei beringei, and Gorilla beringei graueri). Phylogenetically corrected ANOVAs were run on the full dataset and several subsets of the full dataset, revealing that, when buccolingual RoCs are taken into account, tooth cusp RoCs can successfully differentiate folivores and frugivores. PCAs revealed that folivores consistently had duller teeth than frugivores. In addition, a weak, statistically significant positive correlation exists between tooth cusp size and tooth cusp RoC. The author hypothesizes differences in tooth cusp RoC are correlated with wear rates, where, per vertical unit of wear, duller cusps will have a longer length of exposed enamel ridge than sharper cusps. More data need to be gathered to determine if the correlation between tooth cusp RoC and tooth cusp size holds true when small primates are considered. Copyright © 2013 Wiley Periodicals, Inc.

Life of a Tooth: A Visual Timeline

Medline Plus

Full Text Available ... Dentist Your Family's Oral Health About the AGD Dental care and oral health information you need from ... Menstrual Calendar for Tooth Extraction Learn what those dental words mean. The Life of a Tooth Home | ...

Is gingival recession a consequence of an orthodontic tooth size and/or tooth position discrepancy? "A paradigm shift".

Science.gov (United States)

Richman, Colin

2011-01-01

Gingival recession (GR) is a commonly observed dental lesion. The underlying etiology has not been clearly identified, although several theories have been suggested. Tooth crowding or tooth malalignment is also frequently observed, with both conditions appearing to be more prevalent in developed countries with heterogeneous populations. A total of 25 consecutively treated patients representing 72 teeth and demonstrating facial clinical GR of > 3 mm were examined clinically, photographically, and with 3-dimensional radiology using conebeam computed tomography. All examined teeth presented with normal interproximal probing depths and attachment levels (teeth demonstrating > 3 mm of GR presented with significantly prominent facial tooth contours and associated alveolar bone dehiscences. Most involved teeth presented with their root structures extending beyond the facial alveolar bony housing (fenestrations). This represents a discrepancy between tooth size and alveolar bone dimensions in the buccolingual, axial, and sagittal orientation. Fewer involved teeth were malpositioned toward the buccal aspect. Both conditions were associated with facial alveolar bone dehiscences and associated GR. This study suggests tooth volume and/or tooth position within the alveolar bony housing strongly correlate with GR. All nonperiodontitis-involved teeth with GR were associated with either wider teeth or facially aligned teeth. However, it is emphasized that all facially aligned teeth, or "larger" teeth, do not necessarily present with GR. Based on these findings, the radiographic-supporting bone index is proposed. This index should facilitate appropriate evaluation of the alveolar bone supporting the mucogingival complex, both on the facial and lingual aspect of teeth. Further investigations are needed to support these preliminary data.

Prevention of dental anomalies in children by prosthetics defects hard tooth tissues and dentitions: the need to possibilities

Directory of Open Access Journals (Sweden)

Suetenkov D.Ye.

2011-03-01

Full Text Available This article presents the possibility of restore the function and anatomy of the tooth and replacement of defects of dentition by prosthesis in children under the removable bite as a method of prevention of dentoalveolar anomalies. Identified the need for prosthetic treatment of children and the willingness of dentists as primary health care professional to address the problems identified. A clinical analysis of complex treatment of defects in the teeth with fixed restorations

Gastroesophageal Reflux Disease and Tooth Erosion

Directory of Open Access Journals (Sweden)

Sarbin Ranjitkar

2012-01-01

Full Text Available The increasing prevalence of gastroesophageal reflux disease (GERD in children and adults, and of “silent refluxers” in particular, increases the responsibility of dentists to be alert to this potentially severe condition when observing unexplained instances of tooth erosion. Although gastroesophageal reflux is a normal physiologic occurrence, excessive gastric and duodenal regurgitation combined with a decrease in normal protective mechanisms, including an adequate production of saliva, may result in many esophageal and extraesophageal adverse conditions. Sleep-related GERD is particularly insidious as the supine position enhances the proximal migration of gastric contents, and normal saliva production is much reduced. Gastric acid will displace saliva easily from tooth surfaces, and proteolytic pepsin will remove protective dental pellicle. Though increasing evidence of associations between GERD and tooth erosion has been shown in both animal and human studies, relatively few clinical studies have been carried out under controlled trial conditions. Suspicion of an endogenous source of acid being associated with observed tooth erosion requires medical referral and management of the patient as the primary method for its prevention and control.

Tooth positioners and their effects on treatment outcome.

Science.gov (United States)

Pravindevaprasad, A; Therese, Beena Agnes

2013-07-01

Malocclusion can also be corrected by means of clear removable appliances called as "tooth positioners" or "aligners". A tooth positioner is used to control settling and to minimize or eliminate relapse of the teeth after an orthodontic treatment. In this article, a complete review of the objectives, course of treatment, fabrication, and the materials used for fabrication of tooth positioners along with their importance and disadvantages were discussed. Tooth positioners did improve the overall orthodontic treatment outcome as quantified by the ABO (American Board of orthodontics) objective scoring method. But once the initial occlusal contact was achieved, the vertical movement of teeth was found to be inhibited.

Tooth-marked small theropod bone: an extremely rare trace

DEFF Research Database (Denmark)

Jacobsen, Aase Roland

2001-01-01

Tooth-marked dinosaur bones provide insight into feeding behaviours and biting strategies of theropod dinosaurs. The majority of theropod tooth marks reported to date have been found on herbivorous dinosaur bones, although some tyrannosaurid bones with tooth marks have also been reported. In 1988...

Association between Severity of Tooth Wear and Dentinal Hypersensitivity

Directory of Open Access Journals (Sweden)

Ashok Ayer

2016-11-01

Full Text Available Background & Objectives: Tooth wear (attrition, abrasion, erosion, and abfraction is perceived globally as ever increasing problem. Several outcome of the tooth wear are hypersensitivity, esthetic problems, functional impairment, annoyance to the patient, and fracture of the tooth. Among these, the measurable and more commonly reported outcome is hypersensitivity to stimuli. Although dentin hypersensitivity is a common clinical condition and is generally reported by the patient after experiencing a sharp, short pain caused by one of the several different external stimuli, it is often inadequately understood. None of the scientific literature available till date attempted to establish the relationship between tooth wear and dentin hypersensitivity which could be a key factor in monitoring those patients.  The aim of the study was to estimate the association between severity of teeth wear and sensitivity in the patients with reported dentinal hypersensitivity.Materials & Methods: Fifty patients with dentin hypersensitivity were investigated for tooth wear. Tooth wear measured using exact tooth wear index and level of sensitivity to stimuli was recorded using a numerical rating scale. Results: Enamel wear at cervical region of teeth showed a positive correlation (p=.010, similarly, dentin wear at cervical region of teeth showed positive correlation and significant association (p<.001 with dentinal hypersensitivity.Conclusion: The observation supports a significant association between severities of tooth surface wear and dentinal hypersensitivity.

Orientation and deformation of mineral crystals in tooth surfaces.

Science.gov (United States)

Fujisaki, Kazuhiro; Todoh, Masahiro; Niida, Atsushi; Shibuya, Ryota; Kitami, Shunsuke; Tadano, Shigeru

2012-06-01

Tooth enamel is the hardest material in the human body, and it is mainly composed of hydroxyapatite (HAp)-like mineral particles. As HAp has a hexagonal crystal structure, X-ray diffraction methods can be used to analyze the crystal structure of HAp in teeth. Here, the X-ray diffraction method was applied to the surface of tooth enamel to measure the orientation and strain of the HAp crystals. The c-axis of the hexagonal crystal structure of HAp was oriented to the surface perpendicular to the tooth enamel covering the tooth surface. Thus, the strain of HAp at the surface of teeth was measured by X-ray diffraction from the (004) lattice planes aligned along the c-axis. The X-ray strain measurements were conducted on tooth specimens with intact surfaces under loading. Highly accurate strain measurements of the surface of tooth specimens were performed by precise positioning of the X-ray irradiation area during loading. The strains of the (004) lattice plane were measured at several positions on the surface of the specimens under compression along the tooth axis. The strains were obtained as tensile strains at the labial side of incisor tooth specimens. In posterior teeth, the strains were different at different measurement positions, varying from tensile to compressive types. Copyright © 2012 Elsevier Ltd. All rights reserved.

Life of a Tooth: A Visual Timeline

Medline Plus

Full Text Available ... Child First See a Dentist? The History of Dental Advances Why is Oral Health Important for Men? What is Baby Bottle Tooth Decay? Learn what those dental words mean. The Life of a Tooth Home | ...

Inhibitory effect of interferon-γ on experimental tooth movement in mice.

Science.gov (United States)

Kohara, Haruka; Kitaura, Hideki; Yoshimatsu, Masako; Fujimura, Yuji; Morita, Yukiko; Eguchi, Toshiko; Yoshida, Noriaki

2012-09-01

The aim of this study was to investigate the effects of interferon (IFN)-γ on experimental tooth movement in mice using a murine experimental tooth movement model. An Ni-Ti closed-coil spring was inserted between the upper-anterior alveolar bones and the upper-left first molars in mice. We evaluated the relationship between local Ifn-γ mRNA levels and orthodontic tooth movement. In other experiments, IFN-γ was injected adjacent to each first molar every other day during tooth movement. After 12 days, the amount of tooth movement was measured. Tartrate-resistant acid phosphatase (TRAP)-positive cells at the pressure side of each experimental tooth were counted as osteoclasts. Local Ifn-γ mRNA expression increased with orthodontic tooth movement. The number of TRAP-positive cells increased on the pressure side of the first molar. In contrast, the degree of tooth movement and the number of TRAP-positive cells on the pressure side in IFN-γ-injected mice were less than those of control mice. IFN-γ was induced in experimental tooth movement, and could inhibit mechanical force-loaded osteoclastogenesis and tooth movement. These results suggest that IFN-γ might be useful in controlling orthodontic tooth movement because of its inhibitory action on excessive osteoclastogenesis during this movement.

Tooth bleaching and young adults in Nigeria: knowledge, experiences and intention.

Science.gov (United States)

Azodo, C C; Ogbomo, A C; Agbor, M A

2012-12-01

To assess the knowledge, experiences and intention to have tooth bleaching among young adults studying in a Nigerian University. A cross-section of part-time undergraduate students of University of Benin, Benin City, Nigeria were studied in 2010 using a self-administered questionnaire. About three-quarters 289 (72.4%) of the respondents reported awareness of at least one cause of tooth discoloration. A total of 143 (35.8%) of the respondents have heard of tooth bleaching with main sources of information being friends/relatives, dentists and the internet. One-third 132 (33.1%) of the respondents correctly identified that the aim of tooth bleaching was to make the teeth whiter. The respondents that had correct knowledge about mechanism, duration and complications of tooth bleaching were 51 (12.8%), 25 (6.3%) and 35 (8.8%) respectively. The major perceived benefits of tooth bleaching reported by the respondents were self confidence boost 152 (38.1%) and improvement of one's beauty 107 (26.8%). Out of the 68 (17.0%) respondents that have attempted tooth bleaching, 36 (52.9%) used tooth whitening toothpaste. Out of the 151 (37.8%) respondents that expressed intention of having tooth bleaching procedure, 32 (21.2%) would pursue the course, no matter the cost. In the studied population, knowledge of tooth discoloration was high, awareness and experiences of tooth bleaching were low but significant number expressed intention of having tooth bleaching. It is important that dentists increase oral health information particularly tooth bleaching information accessibility to the young adult population to improve the knowledge and prevent adverse effects.

Tooth Decay Process: How to Reverse It and Avoid a Cavity

Science.gov (United States)

... Health Info Health Topics Tooth Decay Tooth decay (dental caries) is damage to a tooth that can happen ... Clinical Trials Show All Clinical Trials Data & Statistics Dental caries (tooth decay) remains the most prevalent chronic disease ...

Cracked tooth syndrome: A report of three cases.

Science.gov (United States)

Sadasiva, Kadandale; Ramalingam, Sathishmuthukumar; Rajaram, Krishnaraj; Meiyappan, Alagappan

2015-08-01

Cracked tooth syndrome (CTS), the term was coined by Cameron in 1964, which refers to an incomplete fracture of a vital posterior tooth extending to the dentin and occasionally into the pulp. CTS has always been a nightmare to the patient because of its unpredictable symptoms and a diagnostic dilemma for the dental practitioner due to its variable, bizarre clinical presentation. The treatment planning and management of CTS has also given problems and challenges the dentist as there is no specific treatment option. The management of CTS varies from one case to another or from one tooth to another in the same individual based on the severity of the symptoms and depth of tooth structure involved. After all, the prognosis of such tooth is still questionable and requires continuous evaluation. This article aims at presenting a series three cases of CTS with an overview on the clinical presentation, diagnosis and the different treatment options that varies from one case to another.

Effect of the partial replacement of sodium chloride by other salts on the formation of volatile compounds during ripening of dry-cured ham.

Science.gov (United States)

Armenteros, Mónica; Toldrá, Fidel; Aristoy, M-Concepción; Ventanas, Jesús; Estévez, Mario

2012-08-08

The effect of the partial NaCl replacement by other salts (potassium, calcium, and magnesium chloride) on the formation of volatile compounds through the processing of dry-cured ham was studied using solid-phase microextraction (SPME). Three salt formulations were considered, namely, I (100% NaCl), II (50% NaCl and 50% KCl), and III (55% NaCl, 25% KCl, 15% CaCl(2), and 5% MgCl(2)). There was an intense formation of volatile compounds throughout the processing of dry-cured hams, particularly during the "hot-cellar" stage. The differences between treatments were found to be more remarkable at the end of the curing process. Hams from formulations I and II had significantly higher amounts of lipid-derived volatiles such as hexanal than hams from formulation III, whereas the latter had significantly higher amounts of Strecker aldehydes and alcohols. Plausible mechanisms by which salt replacement may affect the generation of volatile compounds include the influence of such replacement on lipid oxidation and proteolysis phenomena. The potential influence of the volatiles profile on the aroma of the products is also addressed in the present paper.

Contaminated tooth brushes-potential threat to oral and general health

Directory of Open Access Journals (Sweden)

Rashmi Naik

2015-01-01

Full Text Available Background: Tooth brushing is most common method of maintaining oral hygiene. In removing plaque and other soft debris from the teeth, tooth brushes become contaminated with bacteria, blood, saliva and oral debris. These contaminated tooth brushes can be a source of infection. Aims and objectives: The aim of the present study was to evaluate the presence of microorganisms in the tooth brushes and to investigate the effect of disinfectants such as chlorhexidine gluconate, sodium hypochlorite and water to decontaminate them. Materials and Methods: Twenty-one children were asked to brush their teeth for 5 days with a tooth brush. The tooth brushes were put in Robertson′s Cooked Meat broth and were observed for growth of Streptococcal microorganisms. These tooth brushes were then placed in disinfectants such as 0.2% chlorhexidine gluconate (Group I, 1% sodium hypochlorite (Group II and water (Group III for 24 hrs and then cultured again. Reduction of growth of microorganisms was seen in Group I, Group II and remnants of growth seen in Group III. Conclusion: We conclude that the use of disinfectant for a tooth brush is a must for every individual at least at regular intervals.

A comparative study on the stress distribution around dental implants in three arch form models for replacing six implants using finite element analysis.

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Zarei, Maryam; Jahangirnezhad, Mahmoud; Yousefimanesh, Hojatollah; Robati, Maryam; Robati, Hossein

2018-01-01

Dental implant is a method to replacement of missing teeth. It is important for replacing the missed anterior teeth. In vitro method is a safe method for evaluation of stress distribution. Finite element analysis as an in vitro method evaluated stress distribution around replacement of six maxillary anterior teeth implants in three models of maxillary arch. In this in vitro study, using ABAQUS software (Simulia Corporation, Vélizy-Villacoublay, France), implant simulation was performed for reconstruction of six maxillary anterior teeth in three models. Two implants were placed on both sides of the canine tooth region (A model); two implants on both sides of the canine tooth region and another on one side of the central incisor region (B model); and two implants on both sides of the canine tooth region and two implants in the central incisor area (C model). All implants evaluated in three arch forms (tapered, ovoid, and square). Data were analyzed by finite analysis software. Von Mises stress by increasing of implant number was reduced. In a comparison of A model in each maxillary arch, the stress created in the cortical and cancellous bones in the square arch was less than ovoid and tapered arches. The stress created in implants and cortical and cancellous bones in C model was less than A and B models. The C model (four-implant) reduced the stress distribution in cortical and cancellous bones, but this pattern must be evaluated according to arch form and cost benefit of patients.

Effect of Melamine Sponge on Tooth Stain Removal.

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Otsuka, Takero; Kawata, Toshitsugu

2015-01-01

To investigate the stain removal ability of melamine sponge before aesthetic tooth whitening in extracted teeth. Melamine sponge of thickness 40 mm was compressed and the destruction of the partition wall structure during the compression process was examined under a stereoscopic microscope. An extracted human tooth was cleaned by normal polishing or with melamine sponge for 90 s. To evaluate the stain level, the tooth surfaces were photographed under a stereoscopic microscope at 0, 30, 60 and 90 s. The residual stained region was traced in a high-magnification photograph, and the stain intensity was presented as a change, relative to the intensity before the experiment (0 s). Mechanical cleaning by toothbrushing produced polishing scratches on the tooth surface, whereas use of the melamine sponge resulted in only minimal scratches. As the compression level increased, the stain-removing effect tended to become stronger. Melamine sponge can remove stains from the tooth surface more effectively and less invasively compared to a conventional toothbrush. As no new scratches are made on the tooth surface when using a melamine sponge brush, the risk of re-staining is reduced. Cleaning using a melamine sponge brush can be easily and effectively performed at home and in a dental office.

An automatic tooth preparation technique: A preliminary study

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Yuan, Fusong; Wang, Yong; Zhang, Yaopeng; Sun, Yuchun; Wang, Dangxiao; Lyu, Peijun

2016-04-01

The aim of this study is to validate the feasibility and accuracy of a new automatic tooth preparation technique in dental healthcare. An automatic tooth preparation robotic device with three-dimensional motion planning software was developed, which controlled an ultra-short pulse laser (USPL) beam (wavelength 1,064 nm, pulse width 15 ps, output power 30 W, and repeat frequency rate 100 kHz) to complete the tooth preparation process. A total of 15 freshly extracted human intact first molars were collected and fixed into a phantom head, and the target preparation shapes of these molars were designed using customised computer-aided design (CAD) software. The accuracy of tooth preparation was evaluated using the Geomagic Studio and Imageware software, and the preparing time of each tooth was recorded. Compared with the target preparation shape, the average shape error of the 15 prepared molars was 0.05-0.17 mm, the preparation depth error of the occlusal surface was approximately 0.097 mm, and the error of the convergence angle was approximately 1.0°. The average preparation time was 17 minutes. These results validated the accuracy and feasibility of the automatic tooth preparation technique.

Motion planning and synchronized control of the dental arch generator of the tooth-arrangement robot.

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Jiang, Jin-Gang; Zhang, Yong-De

2013-03-01

The traditional, manual method of reproducing the dental arch form is prone to numerous random errors caused by human factors. The purpose of this study was to investigate the automatic acquisition of the dental arch and implement the motion planning and synchronized control of the dental arch generator of the multi-manipulator tooth-arrangement robot for use in full denture manufacture. First, the mathematical model of the dental arch generator was derived. Then the kinematics and control point position of the dental arch generator of the tooth arrangement robot were calculated and motion planning of each control point was analysed. A hardware control scheme is presented, based on the industrial personal computer and control card PC6401. In order to gain single-axis, precise control of the dental arch generator, we studied the control pulse realization of high-resolution timing. Real-time, closed-loop, synchronous control was applied to the dental arch generator. Experimental control of the dental arch generator and preliminary tooth arrangement were gained by using the multi-manipulator tooth-arrangement robotic system. The dental arch generator can automatically generate a dental arch to fit a patient according to the patient's arch parameters. Repeated positioning accuracy is 0.12 mm for the slipways that drive the dental arch generator. The maximum value of single-point error is 1.83 mm, while the arc-width direction (x axis) is -33.29 mm. A novel system that generates the dental arch has been developed. The traditional method of manually determining the dental arch may soon be replaced by a robot to assist in generating a more individual dental arch. The system can be used to fabricate full dentures and bend orthodontic wires. Copyright © 2012 John Wiley & Sons, Ltd.

Predatory behaviour of carnivorous dinosaurs: Ecological interpretations based on tooth marked dinosaur bones and wear patterns of theropod teeth

DEFF Research Database (Denmark)

Jacobsen, Aase Roland

Predation marks on bones are a source on information on the feeding behaviour of the carnivores involved. Although predator damaged bone is common in the fossil record, published reports of such marks on dinosaur bones are rare. Patterns of bone modification by mammalian carnivores overlap patterns...... left by theropod dinosaurs.Differences in tooth morphology can also be correlated with characteristics of the marks left by the teeth. In a study of tooth marks on dinosaur bones from the Dinosaur Park Formation of Alberta, Canada, it was possible to identify the feeding theropods to family, generic...... different taxa and different skeletal elements produced some interesting results. The frequency of tooth marked dinosaur bones is higher than expected. Up to 14 % of the observed hadrosaur bones were predator damaged. The lower incidence of damage in ceratopsian bones can be explained by the fact...

Periodontal profile classes predict periodontal disease progression and tooth loss.

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Morelli, Thiago; Moss, Kevin L; Preisser, John S; Beck, James D; Divaris, Kimon; Wu, Di; Offenbacher, Steven

2018-02-01

Current periodontal disease taxonomies have limited utility for predicting disease progression and tooth loss; in fact, tooth loss itself can undermine precise person-level periodontal disease classifications. To overcome this limitation, the current group recently introduced a novel patient stratification system using latent class analyses of clinical parameters, including patterns of missing teeth. This investigation sought to determine the clinical utility of the Periodontal Profile Classes and Tooth Profile Classes (PPC/TPC) taxonomy for risk assessment, specifically for predicting periodontal disease progression and incident tooth loss. The analytic sample comprised 4,682 adult participants of two prospective cohort studies (Dental Atherosclerosis Risk in Communities Study and Piedmont Dental Study) with information on periodontal disease progression and incident tooth loss. The PPC/TPC taxonomy includes seven distinct PPCs (person-level disease pattern and severity) and seven TPCs (tooth-level disease). Logistic regression modeling was used to estimate relative risks (RR) and 95% confidence intervals (CI) for the association of these latent classes with disease progression and incident tooth loss, adjusting for examination center, race, sex, age, diabetes, and smoking. To obtain personalized outcome propensities, risk estimates associated with each participant's PPC and TPC were combined into person-level composite risk scores (Index of Periodontal Risk [IPR]). Individuals in two PPCs (PPC-G: Severe Disease and PPC-D: Tooth Loss) had the highest tooth loss risk (RR = 3.6; 95% CI = 2.6 to 5.0 and RR = 3.8; 95% CI = 2.9 to 5.1, respectively). PPC-G also had the highest risk for periodontitis progression (RR = 5.7; 95% CI = 2.2 to 14.7). Personalized IPR scores were positively associated with both periodontitis progression and tooth loss. These findings, upon additional validation, suggest that the periodontal/tooth profile classes and the derived

Results of tooth enamel EPR dosimetry for population living in the vicinity of the Semipalatinsk nuclear test site

Energy Technology Data Exchange (ETDEWEB)

Zhumadilov, K. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan)], E-mail: kassym@hiroshima-u.ac.jp; Ivannikov, A. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan); Medical Radiological Research Center, Obninsk, 249036 (Russian Federation); Apsalikov, K. [Scientific-Research Institute for Radiation Medicine and Ecology, Semipalatinsk 490050 (Kazakhstan); Zhumadilov, Zh. [Semipalatinsk State Medical Academy, Semipalatinsk 490050 (Kazakhstan); Zharlyganova, D. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan); Stepanenko, V.; Skvortsov, V. [Medical Radiological Research Center, Obninsk, 249036 (Russian Federation); Berekenova, G. [Scientific-Research Institute for Radiation Medicine and Ecology, Semipalatinsk 490050 (Kazakhstan); Toyoda, S. [Department of Applied Physics Faculty of Science Okayama University of Science, 700-0005 (Japan); Endo, S.; Tanaka, K. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan); Miyazawa, C. [School of Dentistry, Ohu University, Koriyama-shi, Fukushima Pref. 963-8611 (Japan); Hoshi, M. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan)

2007-07-15

The method of electron paramagnetic resonance (EPR) dosimetry was used on human tooth enamel to obtain individual absorbed doses of residents of settlements in the vicinity of the Nuclear Test Site (SNTS) in Semipalatinsk region, Kazakhstan. Measured teeth were extracted according to medical indications. In total, 105 tooth enamel samples were analyzed, including eight tooth samples from control settlement Kokpekty, which is located 400 km to the Southeast from SNTS and was not subjected to any radioactive contamination. It was found that the excess doses obtained after subtraction of the contribution of natural background radiation ranged up to about 440 mGy for residents of Dolon, whose tooth enamel was formed before 1949, and do not exceed 100 mGy for younger residents. For residents of Mostik, excess doses do not exceed 100 mGy for all ages except in one resident, for whom an extremely high dose of 1250 mGy was registered. For Bodene settlement, excess doses higher than 100 mGy were obtained for two samples from the residents having enamel formed before 1949. An extremely high dose (2800{+-}400 mGy) was obtained for one resident of Semipalatinsk City. The average excess dose for Semipalatinsk samples with enamel formation before 1949 was determined close to the average excess dose for tooth enamel samples from Dolon village.

Safety issues of tooth whitening using peroxide-based materials.

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Li, Y; Greenwall, L

2013-07-01

In-office tooth whitening using hydrogen peroxide (H₂O₂) has been practised in dentistry without significant safety concerns for more than a century. While few disputes exist regarding the efficacy of peroxide-based at-home whitening since its first introduction in 1989, its safety has been the cause of controversy and concern. This article reviews and discusses safety issues of tooth whitening using peroxide-based materials, including biological properties and toxicology of H₂O₂, use of chlorine dioxide, safety studies on tooth whitening, and clinical considerations of its use. Data accumulated during the last two decades demonstrate that, when used properly, peroxide-based tooth whitening is safe and effective. The most commonly seen side effects are tooth sensitivity and gingival irritation, which are usually mild to moderate and transient. So far there is no evidence of significant health risks associated with tooth whitening; however, potential adverse effects can occur with inappropriate application, abuse, or the use of inappropriate whitening products. With the knowledge on peroxide-based whitening materials and the recognition of potential adverse effects associated with the procedure, dental professionals are able to formulate an effective and safe tooth whitening regimen for individual patients to achieve maximal benefits while minimising potential risks.

The prevalence of deciduous tooth wear in six-year-old children and its relationship with potential explanatory factors.

Science.gov (United States)

Rios, Daniela; Magalhães, Ana Carolina; Honório, Heitor Marques; Buzalaf, Marília Afonso Rabelo; Lauris, José Roberto Pereira; Machado, Maria Aparecida Andrade Moreira

2007-01-01

To evaluate the prevalence and aetiological factors involved with wear of deciduous teeth. A convenience sample of 356 children (aged 6 years old) was selected at Bauru, SP (Brazil). Clinical examinations were carried out by 1 examiner (Kappa = 0.87), using the Tooth Wear Index (G0-G4). A questionnaire addressing the aetiological factors of tooth wear was applied to parents. Wear on the incisors was diagnosed in 34.8% of children (91.1% G1 and 6.4% G2); 78.1% presented wear in canines (64.7% G1 and 33.1% G2); and 40.7% in molars (89.6% G1 and 9.0% G2). No significant correlation was observed between gastro-oesophageal reflux, toothbrushing habits, or consumption of citrus fruits/soft drinks and the presence of tooth wear for all groups of teeth. The wear showed correlation with the presence of bruxism for canines and with the habit of holding drinks in the mouth before swallowing for incisors (Chi-square test, p < 0.05). The findings indicate that the wear of incisors could be considered physiological for this age. Further longitudinal studies should be conducted in order to measure the wear in canines and molars in the period close to their replacement by permanent teeth.

Effect of light energy on peroxide tooth bleaching.

Science.gov (United States)

Luk, Karen; Tam, Laura; Hubert, Manfred

2004-02-01

Light-activated bleaching is a method of tooth whitening. The authors conducted a study to compare the whitening effects and tooth temperature changes induced by various combinations of peroxide bleaches and light sources. The authors randomly assigned 250 extracted human teeth halves into experimental groups (n = 10). A placebo gel (control), a 35 percent hydrogen peroxide or a 10 percent carbamide peroxide bleach was placed on the tooth surface and was irradiated with no light (control); a halogen curing light; an infrared, or IR, light; an argon laser; or a carbon dioxide, or CO2, laser. Color changes were evaluated immediately, one day and one week after treatment using a value-oriented shade guide and an electronic dental color analyzer. The outer enamel and inner dentin surface temperatures were monitored before and immediately after each 30-second application of light using a thermocouple thermometer. Color and temperature changes were significantly affected by an interaction of the bleach and light variables. The application of lights significantly improved the whitening efficacy of some bleach materials, but it caused significant temperature increases in the outer and inner tooth surfaces. The IR and CO2 laser lights caused the highest tooth temperature increases. Dentists performing an in-office bleaching technique with the use of an additional light source to accelerate tooth whitening should consider the specific bleaching agent being used, as well as the potential risks of heating teeth. A specific combination of bleach and light that demonstrates good color change and little temperature rise should be selected for in-office tooth bleaching.

Autotransplantation donor tooth site harvesting using piezosurgery.

Science.gov (United States)

Ylikontiola, Leena P; Sándor, George K

2016-01-01

The harvesting of a tooth as a candidate for tooth autotransplantation requires that the delicate dental tissues around the tooth be minimally traumatized. This is especially so for the periradicular tissues of the tooth root and the follicular tissues surrounding the crown. The aim of this report is to describe the use of piezosurgery as an attempt at morbidity reduction in the harvesting of teeth for autotransplantation. A piezosurgical handpiece and its selection of tips were easily adapted to allow the harvesting and delivery of teeth for autotransplantation purposes. Twenty premolar teeth were harvested using a piezosurgical device. The harvested teeth were subsequently successfully autotransplanted. All twenty teeth healed in a satisfactory manner without excessive mobility or ankyloses. Piezosurgery avoids some of the traumatic aspects of harvesting teeth and removing bone which are associated with thermal damage from the use of conventional rotary instruments or saws. Piezosurgery can be adapted to facilitate the predictable harvesting of teeth for autotransplantation purposes.

Innovative Design and Performance Evaluation of Bionic Imprinting Toothed Wheel.

Science.gov (United States)

Zhang, Zhihong; Wang, Xiaoyang; Tong, Jin; Stephen, Carr

2018-01-01

A highly efficient soil-burrowing dung beetle possesses an intricate outer contour curve on its foreleg end-tooth. This study was carried out based on evidence that this special outer contour curve has the potential of reducing soil penetration resistance and could enhance soil-burrowing efficiency. A toothed wheel is a typical agricultural implement for soil imprinting, to increase its working efficiency; the approach of the bionic geometrical structure was utilized to optimize the innovative shape of imprinting toothed wheel. Characteristics in the dung beetle's foreleg end-tooth were extracted and studied by the edge detection technique. Then, this special outer contour curve was modeled by a nine-order polynomial function and used for the innovative design of imprinting the tooth's cutting edge. Both the conventional and bionic teeth were manufactured, and traction tests in a soil bin were conducted. Taking required draft force and volume of imprinted microbasin as the evaluating indexes, operating efficiency and quality of different toothed wheels were compared and investigated. Results indicate that compared with the conventional toothed wheel, a bionic toothed wheel possesses a better forward resistance reduction property against soil and, meanwhile, can enhance the quality of soil imprinting by increasing the volume of the created micro-basin.

Tooth brushing among 11- to 15-year-olds in Denmark

DEFF Research Database (Denmark)

Bast, L. S.; Holstein, B. E.; Nordahl, Helene

2015-01-01

brushing. Results: 10,607 respondents: a response rate of 88.3%. Boys of lower social class had higher odds ratio (OR) of infrequent tooth brushing than girls: 1.98 (95% confidence interval 1.62-2.41) vs 1.80 (1.53-2.24). Immigrants and descendants had higher odds compared to adolescents of Danish origin......Objective: Regular tooth brushing in adolescence predicts stable tooth brushing habits later in life. Differences in tooth brushing habits by ethnic background and socioeconomic position have been suggested. We investigated migration status and social class in relation to infrequent tooth brushing...... both separately and combined. Methods: The study population was 11-15 year-olds chosen from a clustered random sample of schools. Univariate and multivariate logistic regression analyses estimated the separate and combined effects of migration status and social class on less than twice daily tooth...

Effect of corm planting density, organic and chemical fertilizers on formation and phosphorus uptake of saffron (Crocus sativus L. replacement corms during phonological stages

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Hassan Feizi

2015-01-01

Full Text Available Saffron (Crocus sativus L. propagates by replacement corms producing from the mother corm after flowering during each season. In order to investigate the effect of corm planting density, organic and chemical fertilizers on formation and phosphorus uptake of saffron replacement corms during phonological stages, a field experiment was conducted as factorial layout based on randomized complete block design with three replications, at Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, during 2013 and 2014 growing seasons. The experimental treatments were all combination of different levels of planting density (25, 50, 75 and 100 corms per m2 and fertilizer sources (manure 25 t. ha-1, chemical fertilizer (N 150 kg ha-1 + P 75 kg ha-1 and control. Due to different sampling dates of replacement corms during phonological stages (21 November, 21 December, 20 January, 20 April and 21 May, respectively, the experimental data were analyzed as factorial - split in time based on a randomized complete block design. Based on results, the highest number of replacement corms lower than 4 g (5.8 corms per plant were observed in fifth sampling stage and then decreased. In all levels of planting density (25 to 100 corms per m2, the effects of manure on increasing the number, weight and phosphorus content of replacement corms in range of 4.1 to 8 and 8.1 to 12 g per plant were significantly higher than chemical fertilizer. In fifth sampling stage, by applying the manure, the weight and phosphorus content of replacement corms in range of 8.1 to 12 g per plant were significantly increased (approximately twice, as compared to chemical fertilizer. It seems the decrease in saffron yield as result to decreasing the corm planting density can be slightly offset by increasing the percentage of larger corms formation per plant.

Tooth color: effects on judgments of attractiveness and age.

Science.gov (United States)

Grosofsky, Alexis; Adkins, Sarah; Bastholm, Robert; Meyer, Leif; Krueger, Lisa; Meyer, Joshua; Torma, Peter

2003-02-01

Tooth whitening has become a very popular procedure. Advertisements for whitening products imply that whiter teeth are more attractive than yellower teeth. We tested this idea empirically by manipulating the tooth color of pictures of male and female targets. Participants' ratings of attractiveness were not influenced by tooth color. Exp. 2 yielded a negative correlation between attractiveness and age ratings: targets judged to be older were rated as less attractive. Unless whiter teeth help in some other way, e.g., improved self-esteem or confidence, it seems that tooth whitening procedures or products are not associated with increased attractiveness to others.

Side effects of external tooth bleaching

DEFF Research Database (Denmark)

Bruzell, E.M.; Pallesen, Ulla; Thoresen, N.R.

2013-01-01

Objective The study was performed to assess the risk of at-home and in-office bleaching procedures, and to recognise potential predictors for side effects. Design Multi-centre, questionnaire-based prospective study with follow-ups at around 14 days and around one year post-treatment. Setting...... General practices and university clinics during the years 2007‑2009 in Scandinavia. Subjects Patients with tooth bleaching as part of the treatment plan. Results The prevalence of experienced tooth sensitivity at first follow-up was independent of bleaching procedure (at-home = 50.3% [n = 143]; in...... attributed to the bleaching treatment in the at-home and in-office groups, respectively. Predictors for side effects were tooth sensitivity, surface loss and gingivitis when observed at inclusion. Treatment-related predictors were bleaching concentration and contact between tray and gingiva. Conclusions...

Clinical evaluation of a newly designed orthodontic tooth brush - A clinical study

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C S Saimbi

2009-01-01

In this study, the newly designed orthodontic tooth brush is compared with an ordinary tooth brush. Results of this study show that the newly designed orthodontic tooth brush is superior in its cleaning efficiency as compared to the ordinary tooth brush. The results show that plaque removing capacity of orthodontic tooth brush is nearly 95-99%.

Effect of high-frequency near-infrared diode laser irradiation on periodontal tissues during experimental tooth movement in rats.

Science.gov (United States)

Gunji, Hidemi; Kunimatsu, Ryo; Tsuka, Yuji; Yoshimi, Yuki; Sumi, Keisuke; Awada, Tetsuya; Nakajima, Kengo; Kimura, Aya; Hiraki, Tomoka; Hirose, Naoto; Yanoshita, Makoto; Tanimoto, Kotaro

2018-02-05

Tooth movement during orthodontic treatment is associated with bone neoplasticity and bone resorption on the tension and pressure sides. Previous clinical studies have suggested that low-power laser irradiation can accelerate tooth movement during orthodontic treatment, although the underlying mechanism remains unclear. In this study, we used a high-frequency near-infrared diode laser that generates less heat and examined the histologic changes in periodontal tissue during experimental tooth movement with laser irradiation. A nickel-titanium closed coil was mounted between the maxillary left side first molar and incisor of rats to model experimental tooth movement. The laser-irradiation and the control groups were set, and the amount of movement of the first molar on 7th and 14th days after the start of pulling of the first molar tooth on the maxillary left was measured by three-dimensional analysis of µCT. After tooth movement, tissue samples from the mesial and tension sides were collected, and successive horizontal sections were prepared and examined using hematoxylin-eosin and TRAP staining and immunohistochemical staining for RANKL, OPG, ALP, and proliferating cell nuclear antigen (PCNA). Changes in tissue temperature following laser irradiation were also examined. Laser irradiation significantly increased tooth movement compared with non-irradiated controls. Histologic staining of the pressure-side mesial root in laser-irradiated rats revealed enhanced RANKL expression and increased numbers of TRAP-positive cells compared with controls. By contrast, on the tension side, laser irradiation led to increased expression of ALP and PCNA. These data indicate that high-frequency near-infrared diode laser irradiation on the pressure side upregulates RANKL expression and accelerates osteoclast differentiation, facilitating bone resorption, whereas bone formation is induced on the tension side. This study demonstrates that high-frequency near-infrared diode laser

Power Consumption Optimization in Tooth Gears Processing

Science.gov (United States)

Kanatnikov, N.; Harlamov, G.; Kanatnikova, P.; Pashmentova, A.

2018-01-01

The paper reviews the issue of optimization of technological process of tooth gears production of the power consumption criteria. The authors dwell on the indices used for cutting process estimation by the consumed energy criteria and their applicability in the analysis of the toothed wheel production process. The inventors proposed a method for optimization of power consumptions based on the spatial modeling of cutting pattern. The article is aimed at solving the problem of effective source management in order to achieve economical and ecological effect during the mechanical processing of toothed gears. The research was supported by Russian Science Foundation (project No. 17-79-10316).

Addressing Tooth Decay in Head Start Children

Science.gov (United States)

Knowlden, Adam P.; Hill, Lawrence F.; Alles-White, Monica L.; Cottrell, Randall R.

2012-01-01

Tooth decay is the most prevalent chronic disease of childhood. Oral health education and dental services are crucial to reducing the number of children afflicted with dental cavities. Due to limited access to preventative care, Head Start children are particularly vulnerable to tooth decay. This article outlines practical implications of a…

Relationship between natural tooth shade and skin colour.

Science.gov (United States)

Nourbakhsh, M; Mousavinejad, N; Adli, A R; Harati, M

2013-06-01

The purpose of this study was to assess the correlation of skin colour and tooth shade. One hundred and twenty six individuals aging between 18 to 25 years participated in this study. Colour of the maxillary central incisors was examined by VITA easy shade. Tooth shades were assigned to four ordinal values. Nivea Beauty Protect Foundation shade sample was used as a guide to assess facial skin colour Shin colours were also assigned to four ordinal values. Spearman test revealed that there was a significant relationship between tooth shade and skin colour Total co-relation factor was 51.6% (p men (p <0 .01). The highest tooth shade prevalence belonged to the second group and the highest skin colour prevalence was also in the second skin colour group.

Potential feasibility of dental stem cells for regenerative therapies: stem cell transplantation and whole-tooth engineering.

Science.gov (United States)

Nakahara, Taka

2011-07-01

Multipotent mesenchymal stem cells from bone marrow are expected to be a somatic stem cell source for the development of new cell-based therapy in regenerative medicine. However, dental clinicians are unlikely to carry out autologous cell/tissue collection from patients (i.e., marrow aspiration) as a routine procedure in their clinics; hence, the utilization of bone marrow stem cells seems impractical in the dental field. Dental tissues harvested from extracted human teeth are well known to contain highly proliferative and multipotent stem cell compartments and are considered to be an alternative autologous cell source in cell-based medicine. This article provides a short overview of the ongoing studies for the potential application of dental stem cells and suggests the utilization of 2 concepts in future regenerative medicine: (1) dental stem cell-based therapy for hepatic and other systemic diseases and (2) tooth replacement therapy using the bioengineered human whole tooth, called the "test-tube dental implant." Regenerative therapies will bring new insights and benefits to the fields of clinical medicine and dentistry.

Power loss analysis in altered tooth-sum spur gearing

Directory of Open Access Journals (Sweden)

Sachidananda H. K.

2018-01-01

Full Text Available The main cause of power loss or dissipation of heat in case of meshed gears is due to friction existing between gear tooth mesh and is a major concern in low rotational speed gears, whereas in case of high operating speed the power loss taking place due to compression of air-lubricant mixture (churning losses and windage losses due to aerodynamic trial of air lubricant mixture which controls the total efficiency needs to be considered. Therefore, in order to improve mechanical efficiency it is necessary for gear designer during gear tooth optimization to consider these energy losses. In this research paper the power loss analysis for a tooth-sum of 100 altered by ±4% operating between a specified center distance is considered. The results show that negative altered tooth-sum gearing performs better as compared to standard and positive altered tooth-sum gearing.

Infrared light sensor applied to early detection of tooth decay

Science.gov (United States)

Benjumea, Eberto; Espitia, José; Díaz, Leonardo; Torres, Cesar

2017-08-01

The approach dentistry to dental care is gradually shifting to a model focused on early detection and oral-disease prevention; one of the most important methods of prevention of tooth decay is opportune diagnosis of decay and reconstruction. The present study aimed to introduce a procedure for early diagnosis of tooth decay and to compare result of experiment of this method with other common treatments. In this setup, a laser emitting infrared light is injected in core of one bifurcated fiber-optic and conduced to tooth surface and with the same bifurcated fiber the radiation reflected for the same tooth is collected and them conduced to surface of sensor that measures thermal and light frequencies to detect early signs of decay below a tooth surface, where demineralization is difficult to spot with x-ray technology. This device will can be used to diagnose tooth decay without any chemicals and rays such as high power lasers or X-rays.

Effect of irradiation on wound healing after tooth extraction in the rachitic rats

Energy Technology Data Exchange (ETDEWEB)

Kim, Mee Kyung; Hwang, Eui Hwan; Lee, Sang Rae [College of Dentistry, Kyung Hee University, Seoul (Korea, Republic of)

2002-03-15

To observe the histopathological changes following irradiation on the wound healing after tooth extraction in the rachitic rats. In order to carry out this study, the rats were divided into four groups: Group 1 (normal diet/non-irradiation group), Group 2 (normal diet/irradiation group), Group 3 (rachitogenic diet/non-irradiation group), and Group 4 (rachitogenic diet/irradiation group). Rachitic changes were induced with rachitogenic diet No. 2 (high calcium, low phosphorus, and Vitamin D deficient diet) for 5 weeks. After the extraction of both maxillary first molars of the rats in Group 2 and 4, the head and neck of the rats were irradiated with single absorbed dose of 10 Gy. The rats were sacrificed at the 1st, 5th, 10th, and 15th day after tooth extraction. The specimens including the extraction wound were sectioned, stained with the hematoxylin-eosin and Masson's trichrome method and examined under the light microscope. In the Group 2, the amount of newly formed bone trabeculae on the periphery of extraction socket and osteoblastic activity were reduced. In the Group 3, epithelial fusion was not revealed on the 5th day after toothe extraction and growth rate of osteoid formation was reduced. In the Group 4, necrotized tissue at the outer surface of extraction socket and destructive changes on the alveolar bones were noted on the 10th day. Epithelial fusion was not revealed and large amounts of osteoclast were noted on alveolar bone on the 15th day. The healing process of wound after tooth extraction was retarded by irradiation and especially in the rachitic rats.

Effect of irradiation on wound healing after tooth extraction in the rachitic rats

International Nuclear Information System (INIS)

Kim, Mee Kyung; Hwang, Eui Hwan; Lee, Sang Rae

2002-01-01

To observe the histopathological changes following irradiation on the wound healing after tooth extraction in the rachitic rats. In order to carry out this study, the rats were divided into four groups: Group 1 (normal diet/non-irradiation group), Group 2 (normal diet/irradiation group), Group 3 (rachitogenic diet/non-irradiation group), and Group 4 (rachitogenic diet/irradiation group). Rachitic changes were induced with rachitogenic diet No. 2 (high calcium, low phosphorus, and Vitamin D deficient diet) for 5 weeks. After the extraction of both maxillary first molars of the rats in Group 2 and 4, the head and neck of the rats were irradiated with single absorbed dose of 10 Gy. The rats were sacrificed at the 1st, 5th, 10th, and 15th day after tooth extraction. The specimens including the extraction wound were sectioned, stained with the hematoxylin-eosin and Masson's trichrome method and examined under the light microscope. In the Group 2, the amount of newly formed bone trabeculae on the periphery of extraction socket and osteoblastic activity were reduced. In the Group 3, epithelial fusion was not revealed on the 5th day after toothe extraction and growth rate of osteoid formation was reduced. In the Group 4, necrotized tissue at the outer surface of extraction socket and destructive changes on the alveolar bones were noted on the 10th day. Epithelial fusion was not revealed and large amounts of osteoclast were noted on alveolar bone on the 15th day. The healing process of wound after tooth extraction was retarded by irradiation and especially in the rachitic rats.

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bracket adhesive resin and tooth conditioner. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a device...

Visualization of Tooth for Non-Destructive Evaluation from CT Images

Energy Technology Data Exchange (ETDEWEB)

Gao, Hui; Chae, Ok Sam [Kyung Hee University, Seoul (Korea, Republic of)

2009-06-15

This paper reports an effort to develop 3D tooth visualization system from CT sequence images as a part of the non-destructive evaluation suitable for the simulation of endodontics, orthodontics and other dental treatments. We focus on the segmentation and visualization for the individual tooth. In dental CT images teeth are touching the adjacent teeth or surrounded by the alveolar bones with similar intensity. We propose an improved level set method with shape prior to separate a tooth from other teeth as well as the alveolar bones. Reconstructed 3D model of individual tooth based on the segmentation results indicates that our technique is a very conducive tool for tooth visualization, evaluation and diagnosis. Some comparative visualization results validate the non-destructive function of our method.

Angulation change of the third molar tooth in orthodontic treatment

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Ardiansyah S. Pawinru

2017-04-01

Full Text Available Objective : Impaction of the third molar tooth mandibular is often found in patients with orthodontic treatment. In orthodontic treatment, extraction cases of impaction of the third molar tooth are usually performed, but the patients often refuse this extraction. Extraction of premolar has a good effect on the third molar mandibular angulation during treatment. Material and Methods : This study is a retrospective clinical study with descriptive analytic to find out the effect of the first mandibular premolar tooth extraction to angulation change of the third molar mandibular in orthodontic treatment with a standard edgewise method. Angulation change was performed by comparing the third molar mandibular angulation before and after orthodontic treatment with panoramic radiographs. Angulation of the third molar tooth mandibular was calculated from the angle formed between the long axis of the tooth with the reference line infraorbita. Results : The sample comprised 60 of impacted mandibular third molar region of the left and right regions of 30 patients who had been treated declared cured in clinic of orthodontic specialist of Dentistry Faculty Padjadjaran University. The sample was divided into three (3 groups of patients before treatment angulation of the third molar tooth mandibular under 300, 300 to 600 and above 60o, then measured change of angulation and observed whether it increased, fixed or decreased. Results were analyzed by T- test and Wilcoxon test showed that there was a significant change in angulation of the third molar mandibular in orthodontic treatment with the first premolar tooth mandibular extraction. Conclusion : This study is that the first premolar tooth mandibular extraction affects the angulation of the third molar tooth mandibular after orthodontic treatment.

Use of postoperative irradiation for the prevention of heterotopic bone formation after total hip replacement

International Nuclear Information System (INIS)

Sylvester, J.E.; Greenberg, P.; Selch, M.T.; Thomas, B.J.; Amstutz, H.

1988-01-01

Formation of heterotopic bone (HTB) following total hip replacement may partially or completely ankylose the joint space, causing pain and/or limiting the range of motion. Patients at high risk for formation of HTB postoperatively include those with previous HTB formation, heterotopic osteoarthritis, and active rheumatoid spondylitis. Patients in these high risk groups have a 63-69% incidence of post-operative HTB formation, usually seen radiographically by 2 months post-operation. From 1980-1986 twenty-nine hips in 28 consecutively treated patients were irradiated post-operatively at the UCLA Center for the Health Sciences. The indication for irradiation was documented HTB formation previously in 26 of the 27 hips presented below. From 1980-1982 patients received 20 Gray (Gy) in 2 Gy fractions; from 1982-1986 the dose was reduced to 10 Gy in 2 Gy fractions. Twenty-seven hips in 26 patients completed therapy and were available for evaluation, with a minimum of 2 month follow-up, and a median follow-up of 12 months. Three of 27 hips developed significant HTB (Brooker grade III or IV) post-operatively, whereas 5 of 27 hips developed minor, nonsymptomatic HTB (Brooker grade I). When irradiation was begun by postoperative day 4, 0 of 17 hips formed significant HTB. If irradiation began after post-operative day 4, 3 of 10 hips formed significant HTB (Brooker grade III or IV). These 3 hips received doses of 10 Gy in one hip and 20 Gy in the other 2 hips. There were no differences in the incidence or severity of side effects in the 10 Gy vs. the 20 Gy treatment groups. Eighteen hips received 10 Gy, 8 hips 20 Gy and, 1 hip 12 Gy. In conclusion, 10 Gy in 5 fractions appears as effective as 20 Gy in 10 fractions at preventing post-operative formation of HTB. For optimal results, treatment should begin as early as possible prior to post-operative day 4

Platelet-rich fibrin-mediated revitalization of immature necrotic tooth

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Navin Mishra

2013-01-01

Full Text Available Contemporary studies have shown that the regeneration of tissues and root elongation is possible in necrotic immature permanent teeth. The purpose of this case report is to add a new vista in regenerative endodontic therapy by using platelet rich fibrin for revitalization of immature non vital tooth. An 11year old boy with the history of trauma was diagnosed with the pulpal necrosis and symptomatic apical periodontitis in tooth #21. Intra oral periapical radiograph showed open apex and associated immature supernumerary tooth with respect to tooth #21. Access preparation and minimal instrumentation was done to remove necrotic debris under copious irrigation with 2.5% sodium hypochlorite. Triple antibiotic paste was packed in the canal for four weeks. During second visit, 5 mL of whole blood was drawn from the medial cubital vein of the patient and blood was then subjected to centrifugation at 2400 rpm for 12 minutes for the preparation of Platelet rich fibrin (PRF utilizing Choukroun′s method. Triple antibiotic paste was removed and canal was dried. PRF clot was pushed to the apical region of tooth #21 using hand pluggers. Three milimetres of Mineral trioxide (MTA was placed in cervical part of the root canal and permanent restoration was done three days later. Clinical examination at 6 and 12 months revealed no sensitivity to percussion and palpation in tooth #21and it responded positively to both electric pulp and cold tests. Radiographic examination showed resolution of periapical rarefaction, further root development and apical closure of the tooth #21 and its associated supernumerary tooth. On the basis of successful outcome of the present case it can be stated that PRF clot may serve as a scaffold for regeneration of necrotic immature teeth.

The Importance of Tooth Decay Prevention in Children under Three

Science.gov (United States)

Milgrom, Peter; Huebner, Colleen; Chi, Donald

2010-01-01

Tooth decay and tooth loss was once the norm but public health interventions have led to major improvements for most people. Nevertheless, not all children have benefited. Dental disease in young children is unacceptably high. Tooth decay is preventable. Early childhood educators are often the first to notice the problem. Professional…

Promoting positive health behaviours--'tooth worm' phenomenon and its implications.

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Gao, X L; Hsu, C Y S; Xu, Y C; Loh, T; Koh, D; Hwarng, H B

2012-03-01

'Tooth worm' is a traditional belief about the pathogen of dental caries (tooth decay). Nevertheless, in our previous study, parental 'tooth worm' belief was linked to a reduced caries risk of their children. This study aimed to further characterize the impact of parental 'tooth worm' belief on their children's caries experience and its psychobehavioural mechanisms. analytic observational study. Thirteen randomly selected kindergartens in Singapore. 1,782 preschoolers aged 3-6 years. Each child received an oral examination and microbiological tests. Parents completed a self-administered questionnaire on their socio-demographic background, oral health knowledge/attitude and child's oral health habits. Multivariate analysis confirmed a reduced chance of 'high caries rate' (number of affected teeth > 2) among children whose parents held the 'tooth worm' belief (Odds Ratio = 0.41; 95% Confidence Interval = 0.19-0.89). With such perception among parents, children brushed their teeth more frequently (p = 0.042). Since no difference in oral hygiene was observed, the health benefit of the "tooth worm" perception may be acquired through the delivery of fluoride (an agent with proven anti-caries effect) during frequent toothbrushing episodes. This study revealed a 'tooth worm' phenomenon, indicating that parental 'tooth worm' belief is associated with early establishment of regular toothbrushing habit and reduction of dental caries in children. This phenomenon and its psychobehavioural mechanisms, enriching our understanding of oral health behaviours, have implications for effective health education.

Orthodontic Tooth Movement with Clear Aligners

OpenAIRE

Drake, Carl T.; McGorray, Susan P.; Dolce, Calogero; Nair, Madhu; Wheeler, Timothy T.

2012-01-01

Clear aligners provide a convenient model to measure orthodontic tooth movement (OTM). We examined the role of in vivo aligner material fatigue and subject-specific factors in tooth movement. Fifteen subjects seeking orthodontic treatment at the University of Florida were enrolled. Results were compared with data previously collected from 37 subjects enrolled in a similar protocol. Subjects were followed prospectively for eight weeks. An upper central incisor was programmed to move 0.5 mm. ev...

Probable biofilm formation in the cheek as a complication of soft tissue filler resulting from improper endodontic treatment of tooth 16

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Marusza W

2012-03-01

Full Text Available Wojciech Marusza1, Grazyna Mlynarczyk2, Romuald Olszanski3, Irina Netsvyetayeva2, Michael Obrowski1, Tommaso Iannitti4, Beniamino Palmieri51Academy of Face Sculpturing, 2Department of Microbiology, Medical University of Warsaw, 3Military Institute of Health Services, Warsaw, Poland; 4Department of Physiology, School of Medicine, University of Kentucky Medical Center, KY, USA; 5Department of General Surgery and Surgical Specialties, University of Modena and Reggio Emilia Medical School, Surgical Clinic, Modena, ItalyAbstract: Injectable filling agents offer the promise of a better appearance without surgery and, among them, hyaluronic acid is the most commonly used. Although complications are rare, it is necessary to know the possible side effects and complications in order to be prepared for their management. That is why many researchers have been focusing on the interactions between hyaluronic acid and pathogens, inflammatory mediators, the immune system, and markers of oxidative stress to achieve efficient drug delivery, given that hyaluronic acid has widening applications in the field of nanomedicine. Here we report the case of a 37-year-old female patient who returned to our clinic with an abscess in her left cheek 3 months after a deep injection of 1 mL of stabilized hyaluronic acid in both cheeks. Steroid and antibiotic therapy was initiated without success, and abscess drainage was performed. Extraction of tooth 16 was performed 11 days after insertion of drains into the abscess. Laboratory blood tests showed acute inflammation of presumed bacterial etiology. Microbiological examination of pus was negative. Bacterial cultures were found in the extracted tooth. After antibiotic therapy, a complete reversal of the pathological process was observed. The present report highlights the need to assess periodontal problems prior to any aesthetic facial treatment. Analyses of further case reports and clinical studies are necessary to understand

Drugs influencing orthodontic tooth movement: An overall review

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Kamatchi Diravidamani

2012-01-01

Full Text Available Orthodontic treatment is based on the premise that when force is delivered to a tooth and thereby transmitted to the adjacent investing tissues, certain mechanical, chemical, and cellular events take place within these tissues, which allow for structural alterations and contribute to the movement of that tooth. Molecules present in drugs and nutrients consumed regularly by patients can reach the mechanically stressed paradental tissues through the circulation and interact with local target cells. The combined effect of mechanical forces and one or more of these agents may be inhibitory, additive, or synergistic. Current orthodontic research aims to develop methods of increasing the tissue concentration of molecules promoting tooth movement, while simultaneously decreasing the concentration of unwanted elements which can produce harmful side effects. This article discusses in detail the various possible drugs that can bring about alterations in the desired orthodontic tooth movement.

Stem cell property of postmigratory cranial neural crest cells and their utility in alveolar bone regeneration and tooth development.

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Chung, Il-Hyuk; Yamaza, Takayoshi; Zhao, Hu; Choung, Pill-Hoon; Shi, Songtao; Chai, Yang

2009-04-01

The vertebrate neural crest is a multipotent cell population that gives rise to a variety of different cell types. We have discovered that postmigratory cranial neural crest cells (CNCCs) maintain mesenchymal stem cell characteristics and show potential utility for the regeneration of craniofacial structures. We are able to induce the osteogenic differentiation of postmigratory CNCCs, and this differentiation is regulated by bone morphogenetic protein (BMP) and transforming growth factor-beta signaling pathways. After transplantation into a host animal, postmigratory CNCCs form bone matrix. CNCC-formed bones are distinct from bones regenerated by bone marrow mesenchymal stem cells. In addition, CNCCs support tooth germ survival via BMP signaling in our CNCC-tooth germ cotransplantation system. Thus, we conclude that postmigratory CNCCs preserve stem cell features, contribute to craniofacial bone formation, and play a fundamental role in supporting tooth organ development. These findings reveal a novel function for postmigratory CNCCs in organ development, and demonstrate the utility of these CNCCs in regenerating craniofacial structures.

Biological Effects of Orthodontic Tooth Movement Into the Grafted Alveolar Cleft.

Science.gov (United States)

Sun, Jian; Zhang, Xiaoyue; Li, Renmei; Chen, Zhengxi; Huang, Yuanliang; Chen, Zhenqi

2018-03-01

Functional stimulus during orthodontic tooth movement into the grafted bone can lead to better alveolar bone grafting outcomes. The aim of this study was to analyze the biological effects of orthodontic tooth movement into the grafted alveolar cleft area with histologic staining, fluorescence staining, and real-time polymerase chain reaction (PCR). An animal model of orthodontic tooth movement into the grafted alveolar cleft area was established in 8-week-old Sprague-Dawley rats. The animals were divided into the experimental group and the control group. Four checkpoints were observed: before orthodontic stimuli, day 1 after orthodontic stimuli, day 3 after orthodontic stimuli, and day 5 after orthodontic stimuli. The cleft bone formation conditions, including the collagen fibers and the activities of the osteoclasts and osteoblasts, were evaluated by histologic staining. The expression of tartrate-resistant acid phosphatase (TRAP), receptor activator nuclear factor κB ligand, and Runt-related transcription factor 2 was detected by real-time PCR in both groups. Hematoxylin-eosin staining showed that the remodeling process of iliac autografts was completed when the orthodontic stress was applied, whereas the bone tissues first showed osteoclastogenesis and then osteogenesis. On the basis of TRAP staining, the osteoclasts increased to the maximal amount on day 3 and decreased thereafter. Evidence from tetracycline fluorescence staining indicated that no obvious changes in osteoblast activity were detected at the early stage; however, it gradually increased, especially in the region close to the root surface. According to real-time PCR, the expression of TRAP increased in both the early and middle stages, that of receptor activator nuclear factor κB ligand increased in the early stage, and that of Runt-related transcription factor 2 increased in the late stage. Moreover, the results showed significant differences between the experimental and control groups

A Rare Case of Charcot-Mari-Tooth Disease Type 2S in a 20-year-old Man

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Natalia A. Shnayder

2017-12-01

Full Text Available Charcot-Marie-Tooth disease type 2 (CMT2S is rare form of Charcot-Marie-Tooth disease (CMT that is characterized by a mutation in the IGHMBP2 gene. This gene encodes a helicase superfamily member that binds a specific DNA sequence from the region of the immunoglobulin mu chain switch. Mutation of this gene leads to spinal muscle atrophy with respiratory distress type 1 and CMT2S. This case report presents a 20-year-old male with genetically confirmed CMT2S having clinical respiratory involvement and symmetrically involved lower extremities. DNA sequencing revealed a previously unknown heterozygous mutation in the exone 2 of the IGHMBP2 gene leading to the replacement of the amino acid in the 46 position of the protein (chr11q13.3: 68673587 G>C. These atypical features widen the clinical spectrum of CMT2S. In describing this clinical case, we also improve diagnostic management and try to increase the alertness of various doctors towards neuromuscular diseases, including CMT.

Extent of tooth decay in the mouth and increased need for replacement of dental restorations: the New England Children's Amalgam Trial.

Science.gov (United States)

Trachtenberg, Felicia; Maserejian, Nancy Nairi; Tavares, Mary; Soncini, Jennifer Ann; Hayes, Catherine

2008-01-01

The purpose of this study was to assess the relationship between baseline caries experience and the restoration replacement rate in children. The 5-year New England Children's Amalgam Trial recruited 534 6- to 10-year-old children with 2 or more carious posterior teeth. The association between decoy and longevity of restorations was assessed. Restorations with no follow-up (N = 391) were excluded from analysis. The average follow-up was 3.0 +/- 1.6 years in 489 children. Restorations with follow-up (N = 3,604) were placed in mouths with a median of 15 dfs/DFS and 8 dft/DFT. The need for replacement increased significantly (P or = 14 dfs/DFS needed replacement, compared to 9% for 2 to 5 dfs/DFS. Comparing dft/DFT after 5 years of follow-up, there was a 23% replacement rate for > or = 12 dft/DFT compared to 10% for 2 to 3 dft/DFT. Decoy in the mouth had a greater association with the need for replacement due to new caries compared to replacement due to recurrent caries. Children with more decoy at the time of restoration placement were at higher risk for replacement of restorations.

[Esthetic analysis on immediate single-tooth implant restoration in anterior maxilla].

Science.gov (United States)

Li, Shao-wei; Wang, Guo-shi; Sha, Yan-zhi

2015-10-01

To evaluate the esthetic outcomes of immediate single-tooth implant restoration in anterior maxilla with the pink esthetic score (PES). Nine patients were treated with 9 Straumann implants by immediate single-tooth implant restoration in anterior maxilla. Assessment of PES after crown placement at 1 week (baseline) and 6 months after implantation was conducted. Statistical analysis was performed using SPSS 16.0 software package. Nine implants achieved a retention rate of 100%. PES for single-tooth implant was 10.33 ± 1.50 at 1 week and 11.44 ± 0.88 at 6 months after crown placement. The difference was significant(P=0.021). This study indicates that immediate single-tooth implant restoration in anterior maxilla is predictable. Immediate single-tooth implantation can result in good clinical esthetic results in most patients with single-tooth missing in anterior maxilla.

Esthetic evaluation of single-tooth implants in the anterior mandible.

Science.gov (United States)

Hof, Markus; Tepper, Gabor; Koller, Barbara; Krainhöfner, Martin; Watzek, Georg; Pommer, Bernhard

2014-09-01

Single-tooth replacement of anterior mandibular teeth is frequently complicated by insufficient bucco-lingual bone width and limited mesio-distal space available for implant placement. The aim of the present study was to assess implant esthetics in the partially edentulous anterior mandible. Esthetic evaluation of 43 anterior mandibular single-tooth implants in 15 women and 28 men was performed using esthetic indices (PES = Pink Esthetic Score, PI = Papilla Index, SES = Subjective Esthetic Score) as well as subjective patients' Visual Analogue Scale (VAS) ratings. Clinical and radiological parameters (implant and crown dimensions, pocket depth, bleeding on probing, plaque, keratinized mucosa, marginal bone level, and distance to adjacent teeth) were tested for influence. Implant esthetics were judged satisfactory (PES ≤10) in 42% of implants compared with a patient satisfaction rate of 87%. Correlation between objective indices (PES/PI: rs  = 0.62, PES/SES: rs  = -0.73, PI/SES: rs  = -0.48) was highly significant (P ≤ 0.001); however, no association to subjective patients' ratings could be observed. Type of prosthetic restoration (single crown vs. tulip-shaped double crowns), mesio-distal crown width as well as anatomic crown length significantly affected esthetic scores. Patients' judgment, by contrast, could not be associated to any prognostic factor. Subjective patient satisfaction with implant esthetics in the partially edentulous anterior mandible is high, however, remains hard to predict or objectively quantify. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Esthetic enhancement of a traumatized anterior tooth with a combination of forced eruption and tooth alignment: a case report

Science.gov (United States)

Kang, So-Hee; Jin, Myoung-Uk; Kim, Sung-Kyo

2016-01-01

Exposing sound structure of a subgingivally fractured tooth using orthodontic extrusion is considered to be a conservative way to re-establish biologic width without sacrificing esthetics or jeopardizing periodontal support of neighboring teeth. When a misaligned tooth is traumatically involved, a more comprehensive approach combining tooth extrusion and re-alignment may be necessary for a successful restorative outcome. This case report describes a successful esthetic management of a patient with complicated crown-root fracture on the maxillary right central incisor and pre-existing malocclusion in the maxillary anterior region. Forced eruption along with re-alignment of teeth by orthodontic movement seems to allow re-positioning of the fracture line to a favorable position and correction of crowding, providing a better esthetic result. PMID:27508163

ISS protocol for EPR tooth dosimetry

International Nuclear Information System (INIS)

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

2000-01-01

The accuracy in Electron Paramagnetic Resonance (EPR) dose reconstruction with tooth enamel is affected by sample preparation, dosimetric signal amplitude evaluation and unknown dose estimate. Worldwide efforts in the field of EPR dose reconstruction with tooth enamel are focused on the optimization of the three mentioned steps in dose assessment. In the present work, the protocol implemented at ISS in the framework of the European Community Nuclear Fission Safety project 'Dose Reconstruction' is presented. A combined mechanical-chemical procedure for ground enamel sample preparation is used. The signal intensity evaluation is carried out with powder spectra simulation program. Finally, the unknown dose is evaluated individually for each sample with the additive dose method. The unknown dose is obtained by subtracting a mean native dose from the back-extrapolated dose. As an example of the capability of the ISS protocol in unknown dose evaluation, the results obtained in the framework of the 2nd International Intercomparison on EPR tooth enamel dosimetry are reported

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

Face-specific Replacement of Calcite by Amorphous Silica Nanoparticles

Science.gov (United States)

Liesegang, M.; Milke, R.; Neusser, G.; Mizaikoff, B.

2016-12-01

Amorphous silica, composed of nanoscale spheres, is an important biomineral, alteration product of silicate rocks on the Earth's surface, and precursor material for stable silicate minerals. Despite constant progress in silica sphere synthesis, fundamental knowledge of natural silica particle interaction and ordering processes leading to colloidal crystals is absent so far. To understand the formation pathways of silica spheres in a geologic environment, we investigated silicified Cretaceous mollusk shell pseudomorphs from Coober Pedy (South Australia) using focused ion beam (FIB)-SEM tomography, petrographic microscopy, µ-XRD, and EMPA. The shells consist of replaced calcite crystals (ionic strength remain constant throughout the replacement process, permitting continuous silica nanoparticle formation and diffusion-limited colloid aggregation. Our study provides a natural example of the transformation of an atomic crystal to an amorphous, mesoscale ordered material; thus, links the research fields of natural colloidal crystal formation, carbonate-silica replacement, and crystallization by oriented particle aggregation (CPA).

Severe tooth wear in Prader-Willi syndrome. A case–control study

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Saeves Ronnaug

2012-05-01

Full Text Available Abstract Background Prader-Willi syndrome (PWS is a rare complex multsystemic genetic disorder characterized by severe neonatal hypotonia, endocrine disturbances, hyperphagia and obesity, mild mental retardation, learning disabilities, facial dysmorphology and oral abnormalities. The purpose of the present study was to explore the prevalence of tooth wear and possible risk factors in individuals with Prader-Willi syndrome. Methods Forty-nine individuals (6-40 years with PWS and an age- and sex-matched control group were included. Tooth wear was evaluated from dental casts and intraoral photographs and rated by four examiners using the Visual Erosion Dental Examination (VEDE scoring system and the individual tooth wear index IA. In accordance with the VEDE scoring system, tooth wear was also evaluated clinically. Whole saliva was collected. Results Mean VEDE score was 1.70 ± 1.44 in the PWS group and 0.46 ± 0.36 in the control group (p A was 7.50 (2.60-30.70 in the PWS group and 2.60 (0.90-4.70 among controls (p A; r = 0.82, p A; r = 0.43, p = 0.002. Tooth grinding was also associated with tooth wear in the PWS group, as indicated by the mean VEDE 2.67 ± 1.62 in grinders and 1.14 ± 0.97 in non-grinders (p = 0.001 and median IA values 25.70 (5.48-68.55 in grinders and 5.70 (1.60-9.10 in non-grinders (p = 0.003. Multivariate linear regression analysis was performed with tooth wear as the dependent variable and PWS (yes/no, age, tooth grinding and saliva secretion as independent variables. PWS (yes/no, age and tooth grinding retained a significant association with tooth wear, VEDE (p A (p  Conclusions Our study provides evidence that tooth wear, in terms of both erosion and attrition, is a severe problem in Prader-Willi syndrome. There is therefore considerable need for prosthodontic rehabilitation in young adults with PWS.

Tooth fragment reattachment techniques-A systematic review.

Science.gov (United States)

Garcia, Fernanda Cristina P; Poubel, Déborah L N; Almeida, Júlio César F; Toledo, Isabela P; Poi, Wilson R; Guerra, Eliete N S; Rezende, Liliana V M L

2018-03-07

Several strategies have been developed for tooth fragment reattachment following fracture. Although many techniques have been reported, there is no consensus on which one has the best results in terms of the bond strength between the fragment and the dentin over time. The aim of this study was to assess the currently reported tooth fragment reattachment techniques for fractured crowns of anterior teeth. The PubMed, LILACS, Web of Science, Cochrane, and Scopus databases were searched in October 2016, and the search was updated in February 2017. A search of the gray literature was performed in Google Scholar and OpenGrey. Reference lists of eligible studies were cross-checked to identify additional studies; gray literature and ongoing trials were investigated. Two authors assessed studies to determine inclusion and undertook data extraction. Case reports/series of three or more cases, cross-sectional studies, cohort studies, and in vivo clinical trials in all languages were included. Five articles remained after screening. These studies predominantly reported on fragment reattachment with composite resin and resin cement. There was little consistency among the studies in regard to the technique used for tooth fragment reattachment and length of the follow-up period. According to the evidence found in the studies included in this review, simple tooth fragment reattachment was the preferred reattachment technique. An increase in the bond strength between tooth fragment and dentin was observed when an intermediate material was used. Further investigation is needed, using standard follow-up periods and larger samples. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Apexification in a non-vital tooth: By control of infection

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Basgauda R Patil

2010-01-01

Full Text Available Endodontic management of immature non-vital permanent teeth in young pediatric patients is a great challenge to dentists. When the pulp of an incompletely formed tooth loses its vitality, then the entire root system has also lost its ability to continue to develop. The walls of the root canals are frequently divergent and open apices make debridement and obturation difficult. Thus, closure of the root apex is very essential for the success of endodontic treatment. Many different materials are used for the apexification procedure, for apical barrier formation and healing. However, in this present case the apical closure was achieved only by means of infection control.

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

Relationship between food habits and tooth erosion occurrence in Malaysian University students.

Science.gov (United States)

Manaf, Zahara Abdul; Lee, Mei Tee; Ali, Nor Hazirah Muhammad; Samynathan, Selvamary; Jie, Ying Phor; Ismail, Noor Hasnani; Bibiana Hui Ying, Yong; Wei Seng, Yeo; Yahya, Nurul Asyikin

2012-04-01

Tooth erosion is a growing dental problem; however, the role of diet in the aetiology of tooth erosion is unclear. A cross-sectional study was conducted to determine the association between tooth erosion occurrence and the consumption of acidic foods and drinks among undergraduate university students. A total of 150 undergraduate students (33 males and 117 females) aged 19 to 24 years at Universiti Kebangsaan Malaysia participated in this study. The Basic Erosive Wear Examination was used to assess the occurrence of tooth erosion. Information regarding dental hygiene practices, usual dietary habits, and consumption of acidic foods and drinks was obtained through a structured questionnaire. In all, 68% of subjects had tooth erosion. Subjects who reported having received information about healthy eating were less likely to have tooth erosion (χ(2) [1, N = 150] = 7.328, P = 0.007). The frequencies of milk (OR = 0.29, 95% CI = 0.13-0.67) and tea/coffee (adjusted OR = 0.42, 95% CI = 0.19-0.95) consumption were negatively associated with tooth erosion. Dental hygiene practice, the frequency and amount of acidic food and drink intake, and body mass index classification were not significantly associated with the risk of tooth erosion (P > 0.05). A high prevalence of tooth erosion was observed among this group of students. Preventive measures, such as dietary advice and increased consumption of milk at a younger age, may reduce the occurrence of tooth erosion among this age group.

Tooth alterations in areas of bisphosphonate-induced osteonecrosis.

Science.gov (United States)

de Camargo Moraes, Paulo; Silva, Carolina Amália Barcellos; Soares, Andresa Borges; Passador-Santos, Fabrício; Corrêa, Maria Elvira Pizzigatti; de Araújo, Ney Soares; de Araújo, Vera Cavalcanti

2015-03-01

Osteonecrosis of the jaw is a potential side effect when using bisphosphonates. Most studies on the effects of bisphosphonates on teeth have been conducted in vitro or in animal models of tooth development. Therefore, the aim of this study was to describe alterations found in human teeth extracted from areas of bisphosphonate-induced osteonecrosis. Using a retrospective study design, 16 teeth from 13 patients were extracted from areas of bisphosphonate-induced osteonecrosis during surgical debridement. The specimens were decalcified and embedded in paraffin. A series of 5-μm sections were prepared, stained with hematoxylin and eosin (H&E) and observed under a light microscope. The majority of the patients were female (53.85 %), with a mean age of 60.23 ± 13.18 years. Zoledronate (IV) was the most common bisphosphonate used (92.3 %), over a mean period of 2 years. The commonest alteration observed was hypercementosis (87.5 %), followed by pulpar necrosis (81.25 %), pulp stones attached to the dentine and loose pulp stones in the pulp chamber and root canals in addition to linear calcifications (68.75 %), dentinoid/osteoid material formation (18.75 %), and dental ankylosis (6.25 %). Patients undergoing bisphosphonate therapy present diverse tooth alterations, which should be closely monitored by clinicians to prevent complications. It is paramount that the teeth involved in oral lesions are always examined. Attention should be drawn to the need to establish preventive measures, in terms of dental treatment, for patients prior to starting bisphosphonate therapy.

Use of third molar transplantation for closure of the oroantral communication after tooth extraction: a report of 2 cases.

Science.gov (United States)

Kitagawa, Yoshimasa; Sano, Kazuo; Nakamura, Mikiko; Ogasawara, Toshiyuki

2003-04-01

This clinical report introduces a promising and unique method for the immediate closure of the oroantral communication (OAC) after tooth extraction: the use of the transplanted third molar with closed apices. In 2 adult patients, OAC caused by the extraction of an upper molar was immediately closed by using a transplanted third molar with complete root formation. After tooth extraction at the recipient site, OAC with perforated mucosa of the sinus floor was confirmed and the donor third molar was transferred to the prepared recipient socket. Endodontic therapy of the transplanted third molar began at 3 weeks after surgery, and prosthetic treatment was completed at 5 months after the operation. These 2 patients were carefully observed both clinically and radiographically. Closure of the OAC was successfully performed, and the transplanted teeth became fixed with the passage of time in these 2 patients. Root resorption did not occur, and good functional results were obtained without any complications. Tooth transplantation of a mature third molar for closure of the OAC is a simple and excellent method because the transplanted tooth not only closes the communication to the maxillary sinus, but it also satisfactorily functions at the recipient site during mastication, even in adult patients.

Use of quantitative light-induced fluorescence to monitor tooth whitening

Science.gov (United States)

Amaechi, Bennett T.; Higham, Susan M.

2001-04-01

The changing of tooth shade by whitening agents occurs gradually. Apart from being subjective and affected by the conditions of the surroundings, visual observation cannot detect a very slight change in tooth color. An electronic method, which can communicate the color change quantitatively, would be more reliable. Quantitative Light- induced Fluorescence (QLF) was developed to detect and assess dental caries based on the phenomenon of change of autofluorescence of a tooth by demineralization. However, stains on the tooth surface exhibit the same phenomenon, and therefore QLF can be used to measure the percentage fluorescence change of stained enamel with respect to surrounding unstained enamel. The present study described a technique of assessing the effect of a tooth-whitening agent using QLF. This was demonstrated in two experiments in which either wholly or partially stained teeth were whitened by intermittent immersion in sodium hypochlorite. Following each immersion, the integrated fluorescence change due to the stain was quantified using QLF. In either situation, the value of (Delta) Q decreased linearly as the tooth regained its natural shade. It was concluded that gradual changing of the shade of discolored teeth by a whitening agent could be quantified using QLF.

To Tell the Tooth

Science.gov (United States)

... Activity Sheets 2018 Brushing Calendar Sports Safety National Nutrition Month Choose Water for a Sparkling Smile Holiday Workshop Thanksgiving Back to School Fourth of July Fun Tooth Fairy Sugar Wars Valentine's Day Halloween Defeat Monster Mouth! Color and ...

The development of complex tooth shape in reptiles

Science.gov (United States)

Zahradnicek, Oldrich; Buchtova, Marcela; Dosedelova, Hana; Tucker, Abigail S.

2014-01-01

Reptiles have a diverse array of tooth shapes, from simple unicuspid to complex multicuspid teeth, reflecting functional adaptation to a variety of diets and eating styles. In addition to cusps, often complex longitudinal labial and lingual enamel crests are widespread and contribute to the final shape of reptile teeth. The simplest shaped unicuspid teeth have been found in piscivorous or carnivorous ancestors of recent diapsid reptiles and they are also present in some extant carnivores such as crocodiles and snakes. However, the ancestral tooth shape for squamate reptiles is thought to be bicuspid, indicating an insectivorous diet. The development of bicuspid teeth in lizards has recently been published, indicating that the mechanisms used to create cusps and crests are very distinct from those that shape cusps in mammals. Here, we introduce the large variety of tooth shapes found in lizards and compare the morphology and development of bicuspid, tricuspid, and pentacuspid teeth, with the aim of understanding how such tooth shapes are generated. Next, we discuss whether the processes used to form such morphologies are conserved between divergent lizards and whether the underlying mechanisms share similarities with those of mammals. In particular, we will focus on the complex teeth of the chameleon, gecko, varanus, and anole lizards using SEM and histology to compare the tooth crown morphology and embryonic development. PMID:24611053

The development of complex tooth shape in reptiles

Directory of Open Access Journals (Sweden)

Oldrich eZahradnicek

2014-02-01

Full Text Available Reptiles have a diverse array of tooth shapes, from simple unicuspid to complex multicuspid teeth, reflecting functional adaptation to a variety of diets and eating styles. In addition to cusps, often complex longitudinal labial and lingual enamel crests are widespread and contribute to the final shape of reptile teeth. The simplest shaped unicuspid teeth have been found in piscivorous or carnivorous ancestors of recent diapsid reptiles and they are also present in some extant carnivores such as crocodiles and snakes. However, the ancestral tooth shape for squamate reptiles is thought to be bicuspid, indicating an insectivorous diet. The development of bicuspid teeth in lizards has recently been published, indicating that the mechanisms used to create cusps and crests are very distinct from those that shape cusps in mammals. Here, we introduce the large variety of tooth shapes found in lizards and compare the morphology and development of bicuspid, tricuspid and pentacuspid teeth, with the aim of understanding how such tooth shapes are generated. Next, we discuss whether the processes used to form such morphologies are conserved between divergent lizards and whether the underlying mechanisms share similarities with those of mammals. In particular, we will focus on the complex teeth of the chameleon, gecko, varanus and anole lizards using SEM and histology to compare the tooth crown morphology and embryonic development.

Mechanisms underlying ectopic persistent tooth-pulp pain following pulpal inflammation.

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Shingo Matsuura

Full Text Available In order to clarify the peripheral mechanisms of ectopic persistent pain in a tooth pulp following pulpal inflammation of an adjacent tooth, masseter muscle activity, phosphorylated extracellular signal-regulated protein kinase (pERK and TRPV1 immunohistochemistries and satellite cell activation using glial fibrillary acidic protein (GFAP immunohistochemistry in the trigeminal ganglion (TG were studied in the rats with molar tooth-pulp inflammation. And, Fluorogold (FG and DiI were also used in a neuronal tracing study to analyze if some TG neurons innervate more than one tooth pulp. Complete Freund's adjuvant (CFA or saline was applied into the upper first molar tooth pulp (M1 in pentobarbital-anesthetized rats, and capsaicin was applied into the upper second molar tooth pulp (M2 on day 3 after the CFA or saline application. Mean EMG activity elicited in the masseter muscle by capsaicin application to M2 was significantly larger in M1 CFA-applied rats compared with M1 vehicle-applied rats. The mean number of pERK-immunoreactive (IR TG cells was significantly larger in M1 CFA-applied rats compared with M1 vehicle-applied rats. Application of the satellite cell inhibitor fluorocitrate (FC into TG caused a significant depression of capsaicin-induced masseter muscle activity and a significant reduction of satellite cell activation. The number of TRPV1-IR TG cells innervating M2 was significantly larger in M1 CFA-applied rats compared with M1 vehicle-applied rats, and that was decreased following FC injection into TG. Furthermore, 6% of TG neurons innervating M1 and/or M2 innervated both M1 and M2. These findings suggest that satellite cell activation following tooth pulp inflammation and innervation of multiple tooth pulps by single TG neurons may be involved in the enhancement of the activity of TG neurons innervating adjacent non-inflamed teeth that also show enhancement of TRPV1 expression in TG neurons, resulting in the ectopic persistent tooth

Computer simulation of gear tooth manufacturing processes

Science.gov (United States)

Mavriplis, Dimitri; Huston, Ronald L.

1990-01-01

The use of computer graphics to simulate gear tooth manufacturing procedures is discussed. An analytical basis for the simulation is established for spur gears. The simulation itself, however, is developed not only for spur gears, but for straight bevel gears as well. The applications of the developed procedure extend from the development of finite element models of heretofore intractable geometrical forms, to exploring the fabrication of nonstandard tooth forms.

Tooth-germ damage by ionizing radiation

International Nuclear Information System (INIS)

Sobkowiak, E.M.; Beetke, E.; Bienengraeber, V.; Held, M.; Kittner, K.H.

1977-01-01

Experiments on animals (four-week-old dogs) were conducted in an investigation made to study the possibility of dose-dependent tooth-germ damage produced by ionizing radiation. The individual doses were 50 R and 200 R, respectively, and they were administered once to three times at weekly intervals. Hyperemia and edemata could be observed on tooth-germ pulps from 150 R onward. Both of these conditions became more acute as the radiation dose increased (from 150 R to 600 R). Possible damage to both the dentin and enamel is pointed out. (author)

A new approach to root formation

OpenAIRE

Vatanpour, Mehdi; Zarei, Mina; Javidi, Maryam; Shirazian, Shiva

2008-01-01

In endodontics, treatment of an open apex tooth with necrotic pulp is a problem. It seems that with promotion of remnants of Hertwig?s epithelial sheath or rest of malassez accompany with a good irrigation of root canal we can expect root formation. (Iranian Endodontic Journal 2008;3:42-43)

Effect of the vitality of the overdenture abutment tooth on stability of the tooth

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Khalid Ahmad Omar Arafa

2016-01-01

Conclusion: It was concluded that the overdenture over vital abutment teeth was more stable, with a lower incidence of tooth mobility and less attachment loss than overdentures placed on nonvital teeth.

Biogeneric tooth: a new mathematical representation for tooth morphology in lower first molars.

Science.gov (United States)

Mehl, Albert; Blanz, Volker; Hickel, Reinhard

2005-08-01

A mathematical representation of tooth morphology may help to improve and automate restorative computer-aided design processes, virtual dental education, and parametric morphology. However, to date, no quantitative formulation has been identified for the description of dental features. The aim of this study was to establish and to validate a mathematical process for describing the morphology of first lower molars. Stone replicas of 170 caries-free first lower molars from young patients were measured three-dimensionally with a resolution of about 100,000 points. First, the average tooth was computed, which captures the common features of the molar's surface quantitatively. For this, the crucial step was to establish a dense point-to-point correspondence between all teeth. The algorithm did not involve any prior knowledge about teeth. In a second step, principal component analysis was carried out. Repeated for 3 different reference teeth, the procedure yielded average teeth that were nearly independent of the reference (less than +/- 40 microm). Additionally, the results indicate that only a few principal components determine a high percentage of the three-dimensional shape variability of first lower molars (e.g. the first five principal components describe 52% of the total variance, the first 10 principal components 72% and the first 20 principal components 83%). With the novel approach presented in this paper, surfaces of teeth can be described efficiently in terms of only a few parameters. This mathematical representation is called the 'biogeneric tooth'.

Regulation of Reactionary Dentine Formation.

Science.gov (United States)

Neves, V C M; Sharpe, P T

2018-04-01

During the treatment of dental caries that has not penetrated the tooth pulp, maintenance of as much unaffected dentine as possible is a major goal during the physical removal of decayed mineral. Damage to dentine leads to release of fossilized factors (transforming growth factor-β [TGF-β] and bone morphogenic protein [BMP]) in the dentine that are believed to stimulate odontoblasts to secrete new "tertiary" dentine (reactionary dentine). This is formed on the pulpal surface of existing dentine and rethickens the dentine. We have previously shown that activation of Wnt/β-catenin signaling is pivotal for tooth repair in exposed pulp injury, and the pathway can be activated by small-molecule GSK-3 antagonists, resulting in enhanced reparative dentine formation. Here, we use a nonexposed pulp injury model to investigate the mechanisms of reactionary dentine formation in vivo, using small molecules to modulate the Wnt/β-catenin, TGF-β, and BMP pathways. We found that a local increase of Wnt activation at the injury site enhances reactionary dentine secretion. In addition, inhibition of TGF-β, BMP, or Wnt pathways does not impede reactionary dentine formation, although inhibition of TGF-β and/or BMP signaling does result in more disorganized, nontubular reactionary dentine. This suggests that Wnt/β-catenin signaling plays no major role in the formation of reactionary dentine, but in common with reparative dentine formation, exogenous elevation of Wnt/β-catenin signaling can enhance tertiary dentine formation. Release of latent TGF-β or BMPs from dentine is not required for the deposition of mineral to form reactionary dentine but does play a role in its organization.

Daylong Effect of Tooth Brushing or Combination Tooth Brushing and Tongue Cleaning Using Antiplaque®Toothpaste on Volatile Sulphur Compound Levels

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Indriasti Indah Wardhany

2013-07-01

Full Text Available Objective: to determine the daylong effect of Antiplaque® toothpaste active copound and the effect of tooth brushing or combination of tooth brushing and tongue cleaning on Volatile Sulphur Compounds (VSC levels. Methods: Clinical experimental double blinded microbiological and clinical examination. Subjects mainly from dental faculty student with or without a chief complain of halitosis. One hundred and twenty subjects were divided into four groups that consist of thirty samples each group. Two group are treatment subjects were divided into four groups that consist thirty samples each group. Two groups are treatment groups using Antiplaque® toothpaste and two groups are control groups using placebo toothpaste. The daylong effects of VSC levels are measured by Halimeter and organoleptic. The intraoral status were measured including periodontal status and tongue index. Result: There are a reduction of VSC levels in both treatment and control group, but the reduction only significant in group using Antiplaque® toothpaste (Wilcoxon signed rank test, p<0.05. There are a reduction of VSC levels in both treatment using Antiplaque® toothpaste, but the combination of tooth brushing and tongue cleaning reduced VSC levels significantly lower than tooth brushing treatment (Mann Whitney U test, P,0.05. Conclusion: Tooth brushing and tongue cleaning using Antiplaque® toothpaste significantly reduced VSC levels.DOI: 10.14693/jdi.v16i2.95

The effect of light-activation sources on tooth bleaching

Science.gov (United States)

Baroudi, Kusai; Hassan, Nadia Aly

2014-01-01

Vital bleaching is one of the most requested cosmetic dental procedures asked by patients who seek a more pleasing smile. This procedure consists of carbamide or hydrogen peroxide gel applications that can be applied in-office or by the patient (at-home/overnight bleaching system). Some in-office treatments utilise whitening light with the objective of speeding up the whitening process. The objective of this article is to review and summarise the current literature with regard to the effect of light-activation sources on in-office tooth bleaching. A literature search was conducted using Medline, accessed via the National Library of Medicine Pub Med from 2003 to 2013 searching for articles relating to effectiveness of light activation sources on in-office tooth bleaching. This study found conflicting evidence on whether light truly improve tooth whitening. Other factors such as, type of stain, initial tooth colour and subject age which can influence tooth bleaching outcome were discussed. Conclusions: The use of light activator sources with in-office bleaching treatment of vital teeth did not increase the efficacy of bleaching or accelerate the bleaching. PMID:25298598

Tooth wear

OpenAIRE

Tušek Ivan; Tušek Jasmina

2014-01-01

Tooth wear is the loss of dental hard tissue that was not caused by decay and represents a common clinical problem of modern man. In the etiology of dental hard tissue lesions there are three dominant mechanisms that may act synergistically or separately:friction (friction), which is caused by abrasion of exogenous, or attrition of endogenous origin, chemical dissolution of dental hard tissues caused by erosion, occlusal stress created by compression and flexion and tension that leads to toot...

Effect of Cervical Lessions on the Tooth FEM Study

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Gabriela Bereşescu

2010-12-01

Full Text Available The approach used until recently concerning the phenomena of dental abfraction points to the conclusion that the cervical area of the tooth, were this type of lesion usually occur, concentrates the stress resulted from the action of the forces applied on various areas on the crown. Moreover, any lesion in the cervical area facilitates the possibility of its advance into the tooth, ultimately fracturing it. Our paper presents a FEM (finite element method study on the results of a mechanical analysis of the phenomena involving the tooth damaged by cervical lesions.

Proteomic Analysis of Human Tooth Pulp: Proteomics of Human Tooth

Czech Academy of Sciences Publication Activity Database

Eckhardt, Adam; Jágr, Michal; Pataridis, Statis; Mikšík, Ivan

2014-01-01

Roč. 40, č. 12 (2014), s. 1961-1966 ISSN 0099-2399 R&D Projects: GA ČR(CZ) GA13-17224S; GA ČR(CZ) GAP206/12/0453; GA MZd(CZ) NT14324 Institutional support: RVO:67985823 Keywords : dentin * human pulp * tandem mass spectrometry * tooth proteome * 2-dimensional gel electrophoresis Subject RIV: FF - HEENT, Dentistry Impact factor: 3.375, year: 2014

Claustral single cell reactions to tooth pulp stimulation in cats.

Science.gov (United States)

Jastreboff, P; Sikora, M; Frydrychowski, A; Słoniewski, P

1983-01-01

Single unit activity in the central region of the claustrum, evoked by electrical stimulation of tooth pulp or paws was studied on cats under chloralose anesthesia. The majority of cells responded in similar manner to stimulation of tooth pulp or paws, but there were cells with clear preference to a given type of stimulation. Latencies of reactions evoked by tooth pulp stimulation were significantly shorter than those for limb stimulation. In the former case latencies as short as 8 rns were observed. It is postulated that the central region of the claustrum receives a projection from the tooth pulp, and that in those cases with very short latency the projection is direct and does not involve the cerebral cortex.

How does domain replacement affect fibril formation of the rabbit/human prion proteins.

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Xu Yan

Full Text Available It is known that in vivo human prion protein (PrP have the tendency to form fibril deposits and are associated with infectious fatal prion diseases, while the rabbit PrP does not readily form fibrils and is unlikely to cause prion diseases. Although we have previously demonstrated that amyloid fibrils formed by the rabbit PrP and the human PrP have different secondary structures and macromolecular crowding has different effects on fibril formation of the rabbit/human PrPs, we do not know which domains of PrPs cause such differences. In this study, we have constructed two PrP chimeras, rabbit chimera and human chimera, and investigated how domain replacement affects fibril formation of the rabbit/human PrPs.As revealed by thioflavin T binding assays and Sarkosyl-soluble SDS-PAGE, the presence of a strong crowding agent dramatically promotes fibril formation of both chimeras. As evidenced by circular dichroism, Fourier transform infrared spectroscopy, and proteinase K digestion assays, amyloid fibrils formed by human chimera have secondary structures and proteinase K-resistant features similar to those formed by the human PrP. However, amyloid fibrils formed by rabbit chimera have proteinase K-resistant features and secondary structures in crowded physiological environments different from those formed by the rabbit PrP, and secondary structures in dilute solutions similar to the rabbit PrP. The results from transmission electron microscopy show that macromolecular crowding caused human chimera but not rabbit chimera to form short fibrils and non-fibrillar particles.We demonstrate for the first time that the domains beyond PrP-H2H3 (β-strand 1, α-helix 1, and β-strand 2 have a remarkable effect on fibrillization of the rabbit PrP but almost no effect on the human PrP. Our findings can help to explain why amyloid fibrils formed by the rabbit PrP and the human PrP have different secondary structures and why macromolecular crowding has different

Tooth erosion and eating disorders: a systematic review and meta-analysis.

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Ana Paula Hermont

Full Text Available BACKGROUND: Eating disorders are associated with the highest rates of morbidity and mortality of any mental disorders among adolescents. The failure to recognize their early signs can compromise a patient's recovery and long-term prognosis. Tooth erosion has been reported as an oral manifestation that might help in the early detection of eating disorders. OBJECTIVES: The aim of this systematic review and meta-analysis was to search for scientific evidence regarding the following clinical question: Do eating disorders increase the risk of tooth erosion? METHODS: An electronic search addressing eating disorders and tooth erosion was conducted in eight databases. Two independent reviewers selected studies, abstracted information and assessed its quality. Data were abstracted for meta-analysis comparing tooth erosion in control patients (without eating disorders vs. patients with eating disorders; and patients with eating disorder risk behavior vs. patients without such risk behavior. Combined odds ratios (ORs and a 95% confidence interval (CI were obtained. RESULTS: Twenty-three papers were included in the qualitative synthesis and assessed by a modified version of the Newcastle-Ottawa Scale. Fourteen papers were included in the meta-analysis. Patients with eating disorders had more risk of tooth erosion (OR = 12.4, 95%CI = 4.1-37.5. Patients with eating disorders who self-induced vomiting had more risk of tooth erosion than those patients who did not self-induce vomiting (OR = 19.6, 95%CI = 5.6-68.8. Patients with risk behavior of eating disorder had more risk of tooth erosion than patients without such risk behavior (Summary OR = 11.6, 95%CI = 3.2-41.7. CONCLUSION: The scientific evidence suggests a causal relationship between tooth erosion and eating disorders and purging practices. Nevertheless, there is a lack of scientific evidence to fulfill the basic criteria of causation between the risk behavior for eating disorders and tooth erosion.

A Dental Hygienist's and Therapist's Guide to the Management of Tooth Erosion.

Science.gov (United States)

Ariyanayagam, Yana

2016-08-01

Dental care professionals can support patients to prevent and manage tooth erosion. The role of the dentist is to restore the structure and function of teeth damaged by acid erosion, while the role of the dental hygienist therapist is to work alongside the dentist to help manage and reduce the risk of tooth erosion. This article will highlight how the dental hygienist or therapist can identify tooth erosion. It will describe the features of tooth erosion and outline the causes. This article will discuss preventative care options for patients who are at risk of tooth erosion, including specific oral hygiene instructions, fluoride advice and use of other dental products.

A design of speed reducer with trapezoidal tooth profile for robot manipulator

Energy Technology Data Exchange (ETDEWEB)

Nam, Won Ki; Oh, Se Hoon [Chung-Ang University, Seoul (Korea, Republic of)

2011-01-15

Robots are increasingly performing human work as manufacturing is automated. Accordingly, the use of precision speed reducers has become essential for achieving precise control of the robot arm position. Curved tooth profiles, such as cycloid or involute tooth profiles, are generally used in precision speed reducers. Speed reducers with cycloid tooth profiles, which enable high precision control, are widely used to manipulate robot systems. This study proposes a speed reducer that has a trapezoidal tooth profile with straight lines. In this work, we mechanically analyzed trapezoidal tooth profiles, and then measured performance was by various tests using a prototype manufactured specifically for this study.

A design of speed reducer with trapezoidal tooth profile for robot manipulator

International Nuclear Information System (INIS)

Nam, Won Ki; Oh, Se Hoon

2011-01-01

Robots are increasingly performing human work as manufacturing is automated. Accordingly, the use of precision speed reducers has become essential for achieving precise control of the robot arm position. Curved tooth profiles, such as cycloid or involute tooth profiles, are generally used in precision speed reducers. Speed reducers with cycloid tooth profiles, which enable high precision control, are widely used to manipulate robot systems. This study proposes a speed reducer that has a trapezoidal tooth profile with straight lines. In this work, we mechanically analyzed trapezoidal tooth profiles, and then measured performance was by various tests using a prototype manufactured specifically for this study

Mesiodistal tooth angulation to segmental occlusal plane in panoramic radiography

International Nuclear Information System (INIS)

Kim, Jae Duk; Kim, Jin Soo; You, Choong Hyun

2005-01-01

To evaluate the stability of the segmental occlusal plane and anatomical line as the reference line for measuring the mesiodistal tooth angulation in panoramic radiography and to determine the mean angle and the range of the mesiodistal tooth angulation in Korean population with normal occlusions. Twenty nine subjects (15 men, 14 women) with normal occlusion were selected. A total of 29 panoramic radiograms were taken at normal head position and then 10 images of 5 subjects selected were repeatedly taken with repositioning 2 times at each of the head down (V-shaped occlusion) and up (horizontal occulsion) for evaluation of stability of adopted reference lines by using PM2002CC (Planmeca, Finland). The images were traced with adoption of two test reference lines and the long axes of the teeth. The mesial angles formed by each reference line and the long axes of the teeth were measured and analyzed. With anatomical reference line, the mesiodistal tooth angulations of the molars showed the significant difference by over 5 degree between the normal and each changed head position. With segmented occlusal reference line, deviations of mesiodistal tooth angulations by the two changed head positions were less than 1 degree. The means, standard deviations, and maximum and minimum values of mesiodistal tooth angulations to segmental occlusal reference line on panoramic radiography were determined. It would appear that mesiodistal tooth angulations to segmental occlusal plane as reference line in panograms are predictable as standards of normal occlusion and useful for evaluation of tooth arrangement between adjacent teeth.

Mesiodistal tooth angulation to segmental occlusal plane in panoramic radiography

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Duk; Kim, Jin Soo; You, Choong Hyun [Chosun University College of Medicine, Kwangju (Korea, Republic of)

2005-03-15

To evaluate the stability of the segmental occlusal plane and anatomical line as the reference line for measuring the mesiodistal tooth angulation in panoramic radiography and to determine the mean angle and the range of the mesiodistal tooth angulation in Korean population with normal occlusions. Twenty nine subjects (15 men, 14 women) with normal occlusion were selected. A total of 29 panoramic radiograms were taken at normal head position and then 10 images of 5 subjects selected were repeatedly taken with repositioning 2 times at each of the head down (V-shaped occlusion) and up (horizontal occulsion) for evaluation of stability of adopted reference lines by using PM2002CC (Planmeca, Finland). The images were traced with adoption of two test reference lines and the long axes of the teeth. The mesial angles formed by each reference line and the long axes of the teeth were measured and analyzed. With anatomical reference line, the mesiodistal tooth angulations of the molars showed the significant difference by over 5 degree between the normal and each changed head position. With segmented occlusal reference line, deviations of mesiodistal tooth angulations by the two changed head positions were less than 1 degree. The means, standard deviations, and maximum and minimum values of mesiodistal tooth angulations to segmental occlusal reference line on panoramic radiography were determined. It would appear that mesiodistal tooth angulations to segmental occlusal plane as reference line in panograms are predictable as standards of normal occlusion and useful for evaluation of tooth arrangement between adjacent teeth.

Comparison of denture tooth movement between CAD-CAM and conventional fabrication techniques.

Science.gov (United States)

Goodacre, Brian J; Goodacre, Charles J; Baba, Nadim Z; Kattadiyil, Mathew T

2018-01-01

Data comparing the denture tooth movement of computer-aided design and computer-aided manufacturing (CAD-CAM) and conventional denture processing techniques are lacking. The purpose of this in vitro study was to compare the denture tooth movement of pack-and-press, fluid resin, injection, CAD-CAM-bonded, and CAD-CAM monolithic techniques for fabricating dentures to determine which process produces the most accurate and reproducible prosthesis. A total of 50 dentures were evaluated, 10 for each of the 5 groups. A master denture was fabricated and milled from prepolymerized poly(methyl methacrylate). For the conventional processing techniques (pack-and-press, fluid resin, and injection) a polyvinyl siloxane putty mold of the master denture was made in which denture teeth were placed and molten wax injected. The cameo surface of each wax-festooned denture was laser scanned, resulting in a standard tessellation language (STL) format file. The CAD-CAM dentures included 2 subgroups: CAD-CAM-bonded teeth in which the denture teeth were bonded into the milled denture base and CAD-CAM monolithic teeth in which the denture teeth were milled as part of the denture base. After all specimens had been fabricated, they were hydrated for 24 hours, and the cameo surface laser scanned. The preprocessing and postprocessing scan files of each denture were superimposed using surface-matching software. Measurements were made at 64 locations, allowing evaluation of denture tooth movement in a buccal, lingual, mesial-distal, and occlusal direction. The use of median and interquartile range values was used to assess accuracy and reproducibility. Levene and Kruskal-Wallis analyses of variance were used to evaluate differences between processing techniques (α=.05). The CAD-CAM monolithic technique was the most accurate, followed by fluid resin, CAD-CAM-bonded, pack-and-press, and injection. CAD-CAM monolithic technique was the most reproducible, followed by pack-and-press, CAD

Roentgenologic investigations for the anterior tooth length

Energy Technology Data Exchange (ETDEWEB)

Cho, Won Pyo; Ahn, Hyung Kyu [College of Dentistry, Seoul National University , Seoul (Korea, Republic of)

1972-11-15

The author measured the length of crown, root and tooth on the films which was taken by intraoral bisecting technic with mesh plate on the films. The films were taken from the dry skulls, dentiform, same patients who had to be removed their upper incisors, and the other patients who admitted for dental care. From this serial experiment the results were made as follows: 1. By using the film and mesh plate in the oral cavity, the real tooth length can be measured easily on the film surfaces. 2. The film distortion in the oral cavity can be avoided when taking the film using the mesh plate and film together. 3. When measuring the film, length of crown was elongated and length of root was shortened. 4. When using the well-trained bisecting technic, the real tooth length can be measured directly on the intraoral film.

Does Online Marketing Truly Replace Traditional Marketing?

OpenAIRE

Gunawan, Emilia Margareth

2013-01-01

This review explains the way how online marketing has been replacing traditional marketing in terms of marketing mix. This replacement might happen, because online marketing can give advantages, i.e., offering on-time delivery, increasing effectiveness of two way interactions between buyer and seller, and creating online communities (Szmigin, et al, 2005). The transition of atoms to bits format reflects that tangible products in traditional marketing is being digitalized. The marketing strate...

Relationship between human tooth enamel free radical concentration and radiation dose

International Nuclear Information System (INIS)

Zhou Yongzeng; Wang Jiadong; Jia Xiaomei; Wu Ke; Cong Jianbo; Sun Cunpu

1999-01-01

Free radical concentrations of 25 adult tooth enamel samples were measured by electron spin resonance (ESR) technique in this paper, and the relationship between free radical concentration of tooth enamel and radiation dose was also investigated. In the 25 adult enamel samples they are 16 male samples and 9 female samples, Ages of tooth donors range from 18-41 years. Difference in background ESR signal intensity between male and female samples was no observed; free radical concentration (or increment of radiation-induced free radical concentration) in tooth enamel increases linearly with increasing of radiation dose. In the case of radiation accident, the study results of this paper could be applied to dose estimation when conditions of ESR measurement of exposed individual tooth enamel are similar to measurement conditions of dose-effect calibration curve in this paper

Australian aboriginal tooth succession, interproximal attrition, and Begg's theory.

Science.gov (United States)

Corruccini, R S

1990-04-01

In 1954, P.R. Begg analyzed interproximal attrition as a prehistorically universal mechanism to reduce tooth size. With modern processed diets and the virtual disappearance of constant interproximal attrition, Begg asserted, teeth remain too large for the arches and become crowded. Later investigators have questioned Begg's estimate of attritional tooth-size reduction, as well as aspects of his theory relating the succession sequence of permanent teeth to different malocclusions. The present paper examines the theory using longitudinal casts and records of modern Australian aborigines who are among the first generation lacking notable interproximal attrition thanks to a "modernized" diet. Deciduous and permanent tooth size, arch size, and occlusal relational variables were analyzed with respect to the expected occlusal outcomes in the absence of attritional tooth reduction. Permanent incisor overjet correlated with crowding status, as predicted by Begg. On the other hand, longer teeth did not relate to crowding in general nor to crowding in relevant local areas or during developmental stages. Unfavorable leeway space did not relate clearly to crowding or other malocclusions. Lowered correlations among structures and narrowness of the maxilla related more significantly to malocclusion. These results are in keeping with recent thinking that small jaws rather than large teeth underlie tooth/arch discrepancy.

Nutritional status, tooth wear and quality of life in Brazilian schoolchildren.

Science.gov (United States)

Andrade, Francisco Juliherme Pires de; Sales-Peres, André de Carvalho; Moura-Grec, Patricia Garcia de; Mapengo, Marta Artemisa Abel; Sales-Peres, Arsenio; Sales-Peres, Sílvia Helena de Carvalho

2016-06-01

To evaluate the correlation among nutritional status, tooth wear and quality of life in Brazilian schoolchildren. The study followed a cross-sectional design. Nutritional status was measured via anthropometry using BMI and tooth wear was measured using the Dental Wear Index; both these assessments were carried out by a trained recorder according to standard criteria. A modified version of the Child Oral Impacts on Daily Performances was used to assess quality of life. City of Bauru, in Brazil. A cluster sample of 396 schoolchildren (194 boys and 202 girls) aged 7-10 years. The anthropometric assessment showed similar situations for both sexes regarding underweight (31·40 % in boys and 30·20 % in girls) and overweight/obesity (33·96 % in boys and 33·17 % in girls). The underweight children showed a greater severity of tooth wear in the primary teeth (OR=0·72; CI 0·36, 1·42), although in the permanent dentition the obese children had a greater severity of tooth wear (OR=1·42; 95 % CI 0·31, 6·55). The tooth wear was correlated with age for both dentitions. Tooth wear in the primary and permanent dentition may be related to nutritional status. Tooth wear and obesity did not have a significant impact on the schoolchildren's perception of quality of life.

Jaw lesions associated with impacted tooth: A radiographic diagnostic guide

Energy Technology Data Exchange (ETDEWEB)

Motazavi, Hamed; Bharvand, Maryam [Dept. of Oral Medicine, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of)

2016-09-15

This review article aimed to introduce a category of jaw lesions associated with impacted tooth. General search engines and specialized databases such as Google Scholar, PubMed, PubMed Central, MedLine Plus, Science Direct, Scopus, and well-recognized textbooks were used to find relevant studies using keywords such as 'jaw lesion', 'jaw disease', 'impacted tooth', and 'unerupted tooth'. More than 250 articles were found, of which approximately 80 were broadly relevant to the topic. We ultimately included 47 articles that were closely related to the topic of interest. When the relevant data were compiled, the following 10 lesions were identified as having a relationship with impacted tooth: dentigerous cysts, calcifying odontogenic cysts, unicystic (mural) ameloblastomas, ameloblastomas, ameloblastic fibromas, adenomatoid odontogenic tumors, keratocystic odontogenic tumors, calcifying epithelial odontogenic tumors, ameloblastic fibro-odontomas, and odontomas. When clinicians encounter a lesion associated with an impacted tooth, they should first consider these entities in the differential diagnosis. This will help dental practitioners make more accurate diagnoses and develop better treatment plans based on patients' radiographs.

Efficacy of tooth whitening with different calcium phosphate-based formulations.

Science.gov (United States)

Jin, Jian; Xu, Xiaohui; Lai, Guangyun; Kunzelmann, Karl-Heinz

2013-08-01

The aim of this in-vitro study was to evaluate the efficacy of tooth whitening using different calcium phosphate-based formulations. Teeth were treated with three different hydroxyapatite preparations at different concentrations and with two control preparations; each tooth was treated a total of three times. After application of the last material, hydrodynamic shear force was applied to mimic mechanical loading. After each treatment, tooth color was measured using a dental spectrophotometer, and the mean changes in L*a*b* values between different measurements were expressed as ∆E. The results indicated significant differences between the materials, but neither dose- nor time-dependent associations were found. The suspension containing tricalcium phosphate (10 wt%) showed the most obvious color change (∆E = 2.20 ± 0.90), while the suspension containing zinc-carbonate-apatite (20 wt%) showed the least obvious color change (∆E = 0.91 ± 0.50). Calcium phosphate-based formulations that can adhere to the enamel surface and contribute to tooth whitening have promising tooth-whitening potential. © 2013 Eur J Oral Sci.

Jaw lesions associated with impacted tooth: A radiographic diagnostic guide

International Nuclear Information System (INIS)

Motazavi, Hamed; Bharvand, Maryam

2016-01-01

This review article aimed to introduce a category of jaw lesions associated with impacted tooth. General search engines and specialized databases such as Google Scholar, PubMed, PubMed Central, MedLine Plus, Science Direct, Scopus, and well-recognized textbooks were used to find relevant studies using keywords such as 'jaw lesion', 'jaw disease', 'impacted tooth', and 'unerupted tooth'. More than 250 articles were found, of which approximately 80 were broadly relevant to the topic. We ultimately included 47 articles that were closely related to the topic of interest. When the relevant data were compiled, the following 10 lesions were identified as having a relationship with impacted tooth: dentigerous cysts, calcifying odontogenic cysts, unicystic (mural) ameloblastomas, ameloblastomas, ameloblastic fibromas, adenomatoid odontogenic tumors, keratocystic odontogenic tumors, calcifying epithelial odontogenic tumors, ameloblastic fibro-odontomas, and odontomas. When clinicians encounter a lesion associated with an impacted tooth, they should first consider these entities in the differential diagnosis. This will help dental practitioners make more accurate diagnoses and develop better treatment plans based on patients' radiographs

Development of Plastic Gear for Power Transmission : Abnormal Wear on the Tooth Root and Tooth Fracture near Pitch Point

OpenAIRE

Terashima, Kenichi; Tsukamoto, Naohisa; Nishida, Noriteru; Shi, Jiasun

1986-01-01

Plastic gears have many excellent characteristics which are locking in metallic gears, such as corrosion resistance, self-lubrication, quiet running, and so forth. The meshing behavior of plastic gears is very different from that of metallic gears. Therefore, the life estimation is very difficult for plastic gears. In this paper, generating and growing mechanisms of abnormal wear which appears fatally near the root of plastic tooth are analyzed, and then it is clarified that tooth fractures w...

A comparison of new and conventional methods for quantification of tooth color

NARCIS (Netherlands)

Burgt, van der T.P.; Bosch, ten J.J.; Borsboom, P.C.F.; Kortsmit, W.J.P.M.

1990-01-01

Tooth color is caused by volume reflection, that is, passage of incident light through the tooth followed by backward emergence. This passage is concurrent with sideward displacement of photons that, in effect, influences the result of usual instrumental methods of determining tooth color. This

SIGNS Molar tooth sign − looking beyond the obvious

African Journals Online (AJOL)

tooth are represented by thick, perpendicular, non-decussated superior cerebellar peduncles, while the 'body' of the molar tooth is formed by the cerebral peduncles of the brainstem with a deep interpeduncular fossa (Fig. 1a).[3]. Diffusion tensor tractography confirms the failure of superior cerebellar peduncle decussation.

TNF-α Upregulates Expression of BMP-2 and BMP-3 Genes in the Rat Dental Follicle – Implications for Tooth Eruption

Science.gov (United States)

Yao, Shaomian; Prpic, Veronica; Pan, Fenghui; Wise, Gary E.

2011-01-01

The dental follicle appears to regulate both the alveolar bone resorption and bone formation needed for tooth eruption. Tumor necrosis factor-alpha ( TNF-α) gene expression is maximally upregulated at postnatal day 9 in the rat dental follicle of the 1st mandibular molar, a time that correlates with rapid bone growth at the base of the tooth crypt, as well as a minor burst of osteoclastogenesis. TNF-α expression is correlated with the expression of bone morphogenetic protein-2 (BMP-2), a molecule expressed in the dental follicle that can promote bone formation. Because BMP-2 signaling may be augmented by bone morphogenetic protein-3 (BMP-3), it was the objective of this study to determine 1) if the dental follicle expresses BMP-3 and 2) if TNF-α stimulates the dental follicle cells to express BMP-2 and BMP-3. Dental follicles were collected from different postnatal ages of rat pups. Dental follicle cells were incubated with TNF-α to study its dosage and time-course effects on gene expression of BMP-2 and BMP-3, as determined by real-time RT-PCR. Next, immunostaining was conducted to confirm if the protein was synthesized and ELISA of the conditioned medium was conducted to determine if BMP-2 was secreted. We found that BMP-3 expression is correlated with the expression of TNF-α in the dental follicle and TNF-α significantly increased BMP-2 and BMP-3 expression in vitro. Immunostaining and ELISA showed that BMP-2 and BMP-3 were synthesized and secreted. This study suggests that TNF-α can upregulate the expression of bone formation genes that may be needed for tooth eruption. PMID:20067418

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)

Treatment of Necrotic Calcified Tooth Using Intentional Replantation Procedure

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Nima Moradi Majd

2014-01-01

Full Text Available Introduction. If the teeth are impacted by a chronic irritant, the pulp space possibly will undergo calcific changes that may impede access opening during root canal treatment. In such cases that conventional endodontic treatment is impossible or impractical, intentional replantation may be considered as a last solution to preserve the tooth. Methods. After failing to perform conventional root canal therapy for a necrotic calcified right mandibular second premolar, the tooth was gently extracted. The root apex was resected and the root end cavity was prepared and filled with calcium enriched mixture (CEM cement. Then, the extracted tooth was replanted in its original position. Results. After a year the tooth was asymptomatic, and the size of periapical radiolucency was remarkably reduced and no clinical sign of ankylosis was observed. Conclusion. Intentional replantation of the necrotic calcified teeth could be considered as an alternative to teeth extraction, especially for the single-rooted teeth and when nonsurgical and surgical endodontic procedures seem impossible.

Tooth wear risk assessment and care-planning in general dental practice.

Science.gov (United States)

O'Toole, S; Khan, M; Patel, A; Patel, N J; Shah, N; Bartlett, D; Movahedi, S

2018-03-09

Objective To assess charting, risk assessment and treatment-planning of tooth wear between recently qualified and experienced dentists in general dental practice.Design Service evaluation.Setting Multi-setting evaluation of three mixed NHS/Private general dental practices in North-East London.Methods The clinical notes of new patient examinations on dentate adults presenting from the 1 October 2016 to 31 December 2016 were audited collecting data on tooth wear charting, risk assessment and treatment planning. Data were analysed using descriptives, chi square and logistic regressions in SPSS. Significance was inferred at p charted for 48% of those attending foundation dentists and 5% of those attending experienced dentists. Diet was assessed in 50.6% of patients examined by foundation dentists and 1.0% of patients examined by experienced dentists. Foundation dentists were more likely to chart tooth wear, risk assess and preventively manage tooth wear compared to experienced dentists (p <0.001).Conclusion This service evaluation highlights that improvements are required in recording, risk assessing and preventive treatment planning of erosive tooth wear. Experienced dentists were less likely to risk assess tooth wear and less likely to provide preventive treatment. Experienced GDPs may benefit from re-training in this area.

Camel molar tooth enamel response to gamma rays using EPR spectroscopy.

Science.gov (United States)

El-Faramawy, N A; El-Somany, I; Mansour, A; Maghraby, A M; Eissa, H; Wieser, A

2018-03-01

Tooth enamel samples from molar teeth of camel were prepared using a combined procedure of mechanical and chemical tooth treatment. Based on electron paramagnetic resonance (EPR) spectroscopy, the dose response of tooth enamel samples was examined and compared to that of human enamel. The EPR dose response of the tooth enamel samples was obtained through irradiation to gamma doses from 1 Gy up to 100 kGy. It was found that the radiation-induced EPR signal increased linearly with gamma dose for all studied tooth enamel samples, up to about 15 kGy. At higher doses, the dose response curve leveled off. The results revealed that the location of the native signal of camel tooth enamel was similar to that of enamel from human molars at 2.00644, but different from that of enamel from cows and goats. In addition, the peak-to-peak width (ΔH pp ) for human and camel molar teeth was similar. It was also found that the response of camel enamel to gamma radiation was 36% lower than that of human enamel. In conclusion, the results indicate the suitability of camel teeth for retrospective gamma dosimetry.

Camel molar tooth enamel response to gamma rays using EPR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

El-Faramawy, N.A.; El-Somany, I. [Ain Shams University, Physics Department, Faculty of Science, Cairo (Egypt); Mansour, A. [National Center for Radiation Research and Technology, Atomic Energy Authority, Cairo (Egypt); Maghraby, A.M.; Eissa, H. [National Institute of Standards (NIS), Ionizing Radiation Metrology Laboratory, Giza (Egypt); Wieser, A. [Helmholtz Zentrum Muenchen-German Research Center for Environmental Health, Department of Radiation Sciences, Institute of Radiation Protection, Neuherberg (Germany)

2018-03-15

Tooth enamel samples from molar teeth of camel were prepared using a combined procedure of mechanical and chemical tooth treatment. Based on electron paramagnetic resonance (EPR) spectroscopy, the dose response of tooth enamel samples was examined and compared to that of human enamel. The EPR dose response of the tooth enamel samples was obtained through irradiation to gamma doses from 1 Gy up to 100 kGy. It was found that the radiation-induced EPR signal increased linearly with gamma dose for all studied tooth enamel samples, up to about 15 kGy. At higher doses, the dose response curve leveled off. The results revealed that the location of the native signal of camel tooth enamel was similar to that of enamel from human molars at 2.00644, but different from that of enamel from cows and goats. In addition, the peak-to-peak width (ΔH{sub pp}) for human and camel molar teeth was similar. It was also found that the response of camel enamel to gamma radiation was 36% lower than that of human enamel. In conclusion, the results indicate the suitability of camel teeth for retrospective gamma dosimetry. (orig.)

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

Accuracy and precision of estimating age of gray wolves by tooth wear

Science.gov (United States)

Gipson, P.S.; Ballard, W.B.; Nowak, R.M.; Mech, L.D.

2000-01-01

We evaluated the accuracy and precision of tooth wear for aging gray wolves (Canis lupus) from Alaska, Minnesota, and Ontario based on 47 known-age or known-minimum-age skulls. Estimates of age using tooth wear and a commercial cementum annuli-aging service were useful for wolves up to 14 years old. The precision of estimates from cementum annuli was greater than estimates from tooth wear, but tooth wear estimates are more applicable in the field. We tended to overestimate age by 1-2 years and occasionally by 3 or 4 years. The commercial service aged young wolves with cementum annuli to within ?? 1 year of actual age, but under estimated ages of wolves ???9 years old by 1-3 years. No differences were detected in tooth wear patterns for wild wolves from Alaska, Minnesota, and Ontario, nor between captive and wild wolves. Tooth wear was not appropriate for aging wolves with an underbite that prevented normal wear or severely broken and missing teeth.

The role of Msx1 and Pax9 in pathogenetic mechanisms of tooth agenesis

Directory of Open Access Journals (Sweden)

Yani Corvianindya Rahayu

2009-09-01

Full Text Available Background: Tooth agenesis is one of the most common developmental anomalies in human, which one or a few teeth are absent because they have never formed, may cause cosmetic or occlusal harm, while severe agenesis which are relatively rare require clinical attention to support and maintain the dental function. Molecular studies have demonstrated that tooth development is under strict genetic control. Purpose: This article want to review the genetic regulating that are responsible for tooth agenesis especially the role of Msx1 and Pax9 in pathogenetic mechanisms of tooth agenesis. Review: Tooth agenesis is a consequence of a qualitatively or quantitatively impaired function of genetic networks, which regulate tooth development. Mutations in Msx1 and Pax9 genes are dominant for tooth agenesis in humans. The Pax9 gene, which codes for a paired domain-containing transcription factor that plays an essential role in the development of mammal dentition, has been associated with selective tooth agenesis in humans and mice. Conclusion: Reduced amount of functional Msx1 or Pax9 protein in the tooth forming cells is able to cause severe and selective tooth agenesis. There are differences in the frequency of agenesis of specific teeth associated with the defects in Msx1 and defects in Pax9.

Anthropology, tooth wear, and occlusion ab origine.

Science.gov (United States)

Young, W G

1998-11-01

The purpose of this essay is to emphasize that anthropology, the study of man in his environments, is a potent tool for scientific discovery and inspiration in dental science. It attempts to capture flashes of creative anthropological insight which have illuminated studies of tooth wear and occlusion in the past. While it documents contributions, understandings, and misunderstandings from Australian and New Zealand dentists, it is not a hagiography. The real saint of this essay is the Australian aborigine. For when men and women are understood in their environments, much is learned from them which challenges preconceptions of our dental science culture. The essay concludes that new, contemporary Australian culture needs to be studied by anthropological approaches if we are to understand how dental erosion is exacerbating tooth wear and damaging the occlusions of contemporary Australians. Much remains to be discovered about contemporary lifestyles, habits, and diets that lead to dental erosion, the principal cause of contemporary tooth wear in this part of the world.

Computer-Assisted Technique for Surgical Tooth Extraction

Directory of Open Access Journals (Sweden)

Hosamuddin Hamza

2016-01-01

Full Text Available Introduction. Surgical tooth extraction is a common procedure in dentistry. However, numerous extraction cases show a high level of difficulty in practice. This difficulty is usually related to inadequate visualization, improper instrumentation, or other factors related to the targeted tooth (e.g., ankyloses or presence of bony undercut. Methods. In this work, the author presents a new technique for surgical tooth extraction based on 3D imaging, computer planning, and a new concept of computer-assisted manufacturing. Results. The outcome of this work is a surgical guide made by 3D printing of plastics and CNC of metals (hybrid outcome. In addition, the conventional surgical cutting tools (surgical burs are modified with a number of stoppers adjusted to avoid any excessive drilling that could harm bone or other vital structures. Conclusion. The present outcome could provide a minimally invasive technique to overcome the routine complications facing dental surgeons in surgical extraction procedures.

Effect of drugs on orthodontic tooth movement

Directory of Open Access Journals (Sweden)

Siti Sarah Aulia Amrullah

2016-06-01

Full Text Available Orthodontic tooth movement is basically a biological response to mechanical forces given to the teeth in orthodontic treatment, which involving the periodontal tissue and alveolar bone, resulting in the release of numerous substances from the dental tissues and surrounding structure. Remodeling changes in periodontal tissues are considered to be essential in effecting orthodontic tooth movement which is the base of orthodontic correction. Molecules produced in various diseased tissues or drugs and nutrients consumed regularly by patients, can influence mechanically stressed periodontal tissue through the circulation and interact with target cell combination of which may be inhibitory, additive or synergize. Medications might have an important influence on the rate of tooth movement, and information on their consumption is essential to adequately discuss treatment planning with patients. Therefore it is imperative to the practitioners being in medical profession, must pay close attention to the drug consumption history of every patient before and during the course of treatment.

Pre-existing Periapical Inflammatory Condition Exacerbates Tooth Extraction–induced BRONJ Lesions in Mice

Science.gov (United States)

Song, Minju; Alshaikh, Abdullah; Kim, Terresa; Kim, Sol; Dang, Michelle; Mehrazarin, Shebli; Shin, Ki-Hyuk; Kang, Mo; Park, No-Hee; Kim, Reuben H.

2016-01-01

Introduction Surgical interventions such as tooth extraction increase a chance of developing osteonecrosis of the jaw (ONJ) in patients receiving bisphosphonates (BPs) for treatment of bone-related diseases. Tooth extraction is often performed to eliminate pre-existing pathological inflammatory conditions that make the tooth unsalvageable; however, the role of such conditions on bisphosphonate-related ONJ (BRONJ) development following tooth extraction is not clearly defined. Here, we examined the effects of periapical periodontitis on tooth extraction-induced BRONJ development in mice. Methods Periapical periodontitis was induced by exposing the pulp of the maxillary first molar for 3 weeks in C57/BL6 mice that were intravenously administered with BP. The same tooth was extracted, and after 3 additional weeks, the mice were harvested for histological, histomorphometric, and histochemical staining analyses. Results Pulp exposure induced periapical radiolucency as demonstrated by increased inflammatory cells, TRAP+ osteoclasts, and bone resorption. When BP was administered, pulp exposure did not induce apical bone resorption despite the presence of inflammatory cells and TRAP+ osteoclasts. While tooth extraction alone induced BRONJ lesions, pulp exposure further increased tooth extraction-induced BRONJ development as demonstrated by the presence of more bone necrosis. Conclusion Our study demonstrates that pre-existing pathological inflammatory condition such as periapical periodontitis is a predisposing factor that may exacerbate BRONJ development following tooth extraction. Our study further provides a clinical implication whereby periapical periodontitis should be controlled before performing tooth extraction in BP-users in order to reduce the risk of developing BRONJ. PMID:27637460

Experience of racism and tooth brushing among pregnant Aboriginal Australians: exploring psychosocial mediators.

Science.gov (United States)

Ben, J; Jamieson, L M; Priest, N; Parker, E J; Roberts-Thomson, K F; Lawrence, H P; Broughton, J; Paradies, Y

2014-09-01

Despite burgeoning evidence regarding the pathways by which experiences of racism influence health outcomes, little attention has been paid to the relationship between racism and oral health-related behaviours in particular. We hypothesised that self-reported racism was associated with tooth brushing, and that this association was mediated by perceived stress and sense of control and moderated by social support. Data from 365 pregnant Aboriginal Australian women were used to evaluate tooth brushing behaviour, sociodemographic factors, psychosocial factors, general health, risk behaviours and racism exposure. Bivariate associations were explored and hierarchical logistic regression models estimated odds ratios (OR) and 95% confidence intervals (CI) for tooth brushing. Perceived stress and sense of control were examined as mediators of the association between self-reported racism and tooth brushing using binary mediation with bootstrapping. High levels of self-reported racism persisted as a risk indicator for tooth brushing (OR 0.51, 95%CI 0.27,0.98) after controlling for significant covariates. Perceived stress mediated the relationship between self-reported racism and tooth brushing: the direct effect of racism on tooth brushing was attenuated, and the indirect effect on tooth brushing was significant (beta coefficient -0.09; bias-corrected 95%CI -0.166,-0.028; 48.1% of effect mediated). Sense of control was insignificant as a mediator of the relationship between racism and tooth brushing. High levels of self-reported racism were associated with non-optimal tooth brushing behaviours, and perceived stress mediated this association among this sample of pregnant Aboriginal women.. Limitations and implications are discussed.

Abalone water-soluble matrix for self-healing biomineralization of tooth defects

Energy Technology Data Exchange (ETDEWEB)

Wen, Zhenliang [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Chen, Jingdi, E-mail: ibptcjd@fzu.edu.cn [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Wang, Hailiang [The Affiliated Stomatological Hospital, Fujian Medical University, Fuzhou 350002 (China); Zhong, Shengnan; Hu, Yimin; Wang, Zhili [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Zhang, Qiqing, E-mail: zhangqiq@126.com [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou 350002 (China); Institute of Biomedical Engineering, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin 300192 (China)

2016-10-01

Enamel cannot heal by itself if damaged. Hydroxyapatite (HAP) is main component of human enamel. Formation of enamel-like materials for healing enamel defects remains a challenge. In this paper, we successfully isolated the abalone water-soluble matrix (AWSM) with 1.53 wt% the abalone water-soluble protein (AWSPro) and 2.04 wt% the abalone water-soluble polysaccharide (AWSPs) from abandoned abalone shell, and self-healing biomineralization of tooth defects was successfully achieved in vitro. Based on X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), hot field emission scanning electron microscopy (HFESEM) and energy dispersive spectrometer (EDS) analysis, the results showed that the AWSM can efficiently induce remineralization of HAP. The enamel-like HAP was successfully achieved onto etched enamel's surface due to the presence of the AWSM. Moreover, the remineralized effect of eroded enamel was growing with the increase of the AWSM. This study provides a solution to the resource waste and environmental pollution caused by abandoned abalone shell, and we provides a new method for self-healing remineralization of enamel defects by AWSM and develops a novel dental material for potential clinical dentistry application. - Graphical abstract: In this paper, we successfully isolated the abalone water-soluble matrix (AWSM) with 1.53 wt% abalone water-soluble protein (AWSPro) and 2.04 wt% abalone water-soluble polysaccharide (AWSPs) from abandoned abalone shell, and self-healing biomineralization of tooth defects was successfully achieved in vitro by self-organized. Display Omitted - Highlights: • Provides a solution to the resource waste and environmental pollution caused by abandoned abalone shell. • The abalone shell water-soluble matrix contains protein and polysaccharide. • The abalone water-soluble matrix can efficiently induce remineralization of HAP by self-organized. • Achieved self-healing biomineralization of tooth defects in

Effects of different preparation procedures during tooth whitening on enamel bonding.

Science.gov (United States)

Wilson, Dustin; Xu, Changqi; Hong, Liang; Wang, Yong

2009-04-01

The objective of this study was to assess effects of some clinically related preparation procedures during tooth whitening on enamel bonding properties. Sixty-two extracted human teeth were cleaned and divided into four groups. Forty-two of the teeth were left with their natural surface intact while 20 teeth were polished to form a flat surface. Half of the tooth served as the experimental side and received one of the two whitening products: Opalescence (10% carbamide peroxide) and Crest Whitestrips (6.5% hydrogen peroxide), for 2 weeks. Post-bleaching intervals included: 1 day, 1 week, and 2 weeks. On these days, tooth (10 mm x 1.5 mm x 1.5 mm) sections were evaluated using Raman spectroscopy, scanning electron microscopy and tensile bond strength tests. T-test, ANOVA test, and mixed model regression analysis were used to assess the differences. No significant difference existed between natural surface and polished surface teeth for all groups at both Day One and Week Two (P > 0.05). On Day One, both treated groups had significant lower bond strength than the control group (P = 0.002). After 2 weeks, no significant difference existed between any group (P = 0.381). SEM indicated that resin-enamel interfaces in bleached enamel exhibited more defects in granular formations when compared to the control. Raman results indicated a lower degree of polymerization (DP) of adhesive at the interface for treated teeth surfaces. In summary, pre-bleaching surface treatments such as polish or non-polish, had no effect on bond strength. Bleaching significantly decreased bond strength initially, but after 2 weeks, bleaching had no significant effect on bond strength. Storage time had significant effect on Opalescence treated enamel, but not on control and Whitestrip treated enamel. The decrease of bond strength may be related to interfacial defects and low DP due to oxygen release after bleaching.

Abalone water-soluble matrix for self-healing biomineralization of tooth defects

International Nuclear Information System (INIS)

Wen, Zhenliang; Chen, Jingdi; Wang, Hailiang; Zhong, Shengnan; Hu, Yimin; Wang, Zhili; Zhang, Qiqing

2016-01-01

Enamel cannot heal by itself if damaged. Hydroxyapatite (HAP) is main component of human enamel. Formation of enamel-like materials for healing enamel defects remains a challenge. In this paper, we successfully isolated the abalone water-soluble matrix (AWSM) with 1.53 wt% the abalone water-soluble protein (AWSPro) and 2.04 wt% the abalone water-soluble polysaccharide (AWSPs) from abandoned abalone shell, and self-healing biomineralization of tooth defects was successfully achieved in vitro. Based on X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), hot field emission scanning electron microscopy (HFESEM) and energy dispersive spectrometer (EDS) analysis, the results showed that the AWSM can efficiently induce remineralization of HAP. The enamel-like HAP was successfully achieved onto etched enamel's surface due to the presence of the AWSM. Moreover, the remineralized effect of eroded enamel was growing with the increase of the AWSM. This study provides a solution to the resource waste and environmental pollution caused by abandoned abalone shell, and we provides a new method for self-healing remineralization of enamel defects by AWSM and develops a novel dental material for potential clinical dentistry application. - Graphical abstract: In this paper, we successfully isolated the abalone water-soluble matrix (AWSM) with 1.53 wt% abalone water-soluble protein (AWSPro) and 2.04 wt% abalone water-soluble polysaccharide (AWSPs) from abandoned abalone shell, and self-healing biomineralization of tooth defects was successfully achieved in vitro by self-organized. Display Omitted - Highlights: • Provides a solution to the resource waste and environmental pollution caused by abandoned abalone shell. • The abalone shell water-soluble matrix contains protein and polysaccharide. • The abalone water-soluble matrix can efficiently induce remineralization of HAP by self-organized. • Achieved self-healing biomineralization of tooth defects in vitro.

Coupling image processing and stress analysis for damage identification in a human premolar tooth.

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Andreaus, U; Colloca, M; Iacoviello, D

2011-08-01

Non-carious cervical lesions are characterized by the loss of dental hard tissue at the cement-enamel junction (CEJ). Exceeding stresses are therefore generated in the cervical region of the tooth that cause disruption of the bonds between the hydroxyapatite crystals, leading to crack formation and eventual loss of enamel and the underlying dentine. Damage identification was performed by image analysis techniques and allowed to quantitatively assess changes in teeth. A computerized two-step procedure was generated and applied to the first left maxillary human premolar. In the first step, dental images were digitally processed by a segmentation method in order to identify the damage. The considered morphological properties were the enamel thickness and total area, the number of fragments in which the enamel is chipped. The information retrieved by the data processing of the section images allowed to orient the stress investigation toward selected portions of the tooth. In the second step, a three-dimensional finite element model based on CT images of both the tooth and the periodontal ligament was employed to compare the changes occurring in the stress distributions in normal occlusion and malocclusion. The stress states were analyzed exclusively in the critical zones designated in the first step. The risk of failure at the CEJ and of crack initiation at the dentin-enamel junction through the quantification of first and third principal stresses, von Mises stress, and normal and tangential stresses, were also estimated. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Erosive and Mechanical Tooth Wear in Viking Age Icelanders.

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Richter, Svend; Eliasson, Sigfus Thor

2017-08-29

(1) Background: The importance of the Icelandic Sagas as a source of information about diet habits in medieval Iceland, and possibly other Nordic countries, is obvious. Extensive tooth wear in archaeological material worldwide has revealed that the main cause of this wear is believed to have been a coarse diet. Near the volcano Hekla, 66 skeletons dated from before 1104 were excavated, and 49 skulls could be evaluated for tooth wear. The purpose of this study was to determine the main causes of tooth wear in light of diet and beverage consumption described in the Sagas; (2) Materials and methods: Two methods were used to evaluate tooth wear and seven for age estimation; (3) Results: Extensive tooth wear was seen in all of the groups, increasing with age. The first molars had the highest score, with no difference between sexes. These had all the similarities seen in wear from a coarse diet, but also presented with characteristics that are seen in erosion in modern Icelanders, through consuming excessive amounts of soft drinks. According to the Sagas, acidic whey was a daily drink and was used for the preservation of food in Iceland, until fairly recently; (4) Conclusions: It is postulated that the consumption of acidic drinks and food, in addition to a coarse and rough diet, played a significant role in the dental wear seen in ancient Icelanders.

Tooth enamel as a naturtal beta dosemeter for bone seeking radionuclides

International Nuclear Information System (INIS)

Wieser, A.; Petzoldt, G.

1996-01-01

EPR dosimetry was done on teeth from residents of villages along the Techa river, Southern Urals, Russia. The residents have a 90 Sr body burden due to massive releases of liquid nuclear waste into the Techa river in the early fifties. A long time after ingestion, strontium is only incorporated into the skeleton and dentine of the adults but not in tooth enamel. Tooth enamel therefore, is measuring the beta dose from the contaminated dentine. Based on experimental data of this study a first approximation of the ingestion dose coefficient of tooth enamel was found to be more than 5 times lower than the value given in ICRP 69 for the bone surface of the skeleton. A similar difference was found earlier for the dose absorbed in tooth enamel and dentine. The result of this study allows the supposition that that the metabolism of strontium is very very similar for tooth dentine and the skeleton. (author)

Management of Tooth Wear: A Holistic, Dental, Medical, and Mental Healthcare Approach.

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Ahmed, Khaled E

2016-08-01

Tooth wear is a condition that affects a substantial cohort of dental patients. It has a measurable impact on patients' satisfaction, and overall quality of life. Recently, with growing evidence, our understanding of the aetiology, progression, and management of tooth wear has evolved. The paper argues that pathological tooth wear should not be solely considered as a dental condition, but rather a dental manifestation of other mental and medical disorders. As such, successful management of tooth wear, and its underlying aetiology, requires a holistic, multidisciplinary management approach, involving dental, medical, and mental healthcare providers.

Behavioral changes during dental appointments in children having tooth extractions

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Mariana Gonzalez Cademartori

2017-01-01

Full Text Available Background: Tooth extractions are associated with anxiety-related situations that can cause behavioral problems in pediatric dental clinics. Aim: We aimed to describe the behavior of children during tooth extraction appointments, compare it to their behavior in preceding and subsequent dental appointments, and assess the behavioral differences according to gender, age, type of dentition, and reason for extraction. Settings and Design: This was a retrospective study based on information obtained from records of children between 6 and 13 years of age who were cared for at the Dentistry School in Pelotas, Brazil. Materials and Methods: Child behavior was assessed during the dental appointment that preceded the tooth extraction, during the tooth extraction appointment, and in the subsequent dental appointment using the Venham Behavior Rating Scale. Statistical Analysis: Results were analyzed using the Pearson Chi-square and McNemar tests. Results: Eighty-nine children were included. Cooperative behavior prevailed in all the dental appointments. The prevalence of “mild/intense protest” was higher in the tooth extraction appointments than in the previous or subsequent dental appointments (P < 0.001. No significant differences in behavior were detected between the type of dentition (primary or permanent teeth, reason for extraction or gender. Conclusion: In this sample of children treated at a dental school, the occurrence of uncooperative behavior was higher during the tooth extraction appointments than in the preceding and subsequent dental appointments.

Dose- and time-dependent effects of clodronate on orthodontic tooth movement

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Enita Nakaš

2017-02-01

Full Text Available Orthodontic tooth movement is the result of bone remodeling that occurs in periodontal ligament and alveolar bone tissue as a response to mechanical loading of the tooth. The aim of this study is to investigate the time- and dose-response effects of locally administered clodronate on tooth movement. Sixty Wistar rats were randomly assigned to 4 groups of 15 specimens: E1 - application of 10 mMol of clodronate in 3-day intervals; E2 - application of 2.5 mMol of clodronate in 3-day intervals; E3 - application of 10 mMol of clodronate in 7-day intervals; E4 - application of 2.5 mMol of clodronate in 7-day intervals. A 50 μL clodronate solution was injected into a subperiosteal area to the right maxillary incisor. The left maxillary incisor served as a control, with an injection of saline solution. In 3-day interval application regime, there was no effect of clodronate dosing on tooth movement. In 7-day interval application regime, decreased tooth movement was observed with 10 mMol compared with 2.5 mMol clodronate concentration. However, decreased tooth movement was also observed when 2.5 mMol of clodronate was applied in 7-versus 3-day intervals. Conversely, no difference was observed when 10 mMol concentration was applied in 3- versus 7-day intervals. When clodronate is applied subperiosteally in the root area, it decreases the tooth movement. Tooth movement is impeded by the higher clodronate dosing, as well as by shorter application interval even with lower dosing. The purpose of future trials should, therefore, be to determine a safe therapeutic dose/interval application of clodronate in humans and their potential side effects.

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.

[Establishment of database with standard 3D tooth crowns based on 3DS MAX].

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Cheng, Xiaosheng; An, Tao; Liao, Wenhe; Dai, Ning; Yu, Qing; Lu, Peijun

2009-08-01

The database with standard 3D tooth crowns has laid the groundwork for dental CAD/CAM system. In this paper, we design the standard tooth crowns in 3DS MAX 9.0 and create a database with these models successfully. Firstly, some key lines are collected from standard tooth pictures. Then we use 3DS MAX 9.0 to design the digital tooth model based on these lines. During the design process, it is important to refer to the standard plaster tooth model. After some tests, the standard tooth models designed with this method are accurate and adaptable; furthermore, it is very easy to perform some operations on the models such as deforming and translating. This method provides a new idea to build the database with standard 3D tooth crowns and a basis for dental CAD/CAM system.

A Systematic Study on Tooth Enamel Microstructures of Lambdopsalis bulla (Multituberculate, Mammalia)--Implications for Multituberculate Biology and Phylogeny.

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Mao, Fangyuan; Wang, Yuanqing; Meng, Jin

2015-01-01

Tooth enamel microstructure is a reliable and widely used indicator of dietary interpretations and data for phylogenetic reconstruction, if all levels of variability are investigated. It is usually difficult to have a thorough examination at all levels of enamel structures for any mammals, especially for the early mammals, which are commonly represented by sparse specimens. Because of the random preservation of specimens, enamel microstructures from different teeth in various species are often compared. There are few examples that convincingly show intraspecific variation of tooth enamel microstructure in full dentition of a species, including multituberculates. Here we present a systematic survey of tooth enamel microstructures of Lambdopsalis bulla, a taeniolabidoid multituberculate from the Late Paleocene Nomogen Formation, Inner Mongolia. We examined enamel structures at all hierarchical levels. The samples are treated differently in section orientations and acid preparation and examined using different imaging methods. The results show that, except for preparation artifacts, the crystallites, enamel types, Schmelzmuster and dentition types of Lambdopsalis are relatively consistent in all permanent teeth, but the prism type, including the prism shape, size and density, may vary in different portions of a single tooth or among different teeth of an individual animal. The most common Schmelzmuster of the permanent teeth in Lambdopsalis is a combination of radial enamel in the inner and middle layers, aprismatic enamel in the outer layer, and irregular decussations in tooth crown area with great curvature. The prism seam is another comparably stable characteristic that may be a useful feature for multituberculate taxonomy. The systematic documentation of enamel structures in Lambdopsalis may be generalized for the enamel microstructure study, and thus for taxonomy and phylogenetic reconstruction, of multituberculates and even informative for the enamel study of

A Systematic Study on Tooth Enamel Microstructures of Lambdopsalis bulla (Multituberculate, Mammalia) - Implications for Multituberculate Biology and Phylogeny

Science.gov (United States)

Mao, Fangyuan; Wang, Yuanqing; Meng, Jin

2015-01-01

Tooth enamel microstructure is a reliable and widely used indicator of dietary interpretations and data for phylogenetic reconstruction, if all levels of variability are investigated. It is usually difficult to have a thorough examination at all levels of enamel structures for any mammals, especially for the early mammals, which are commonly represented by sparse specimens. Because of the random preservation of specimens, enamel microstructures from different teeth in various species are often compared. There are few examples that convincingly show intraspecific variation of tooth enamel microstructure in full dentition of a species, including multituberculates. Here we present a systematic survey of tooth enamel microstructures of Lambdopsalis bulla, a taeniolabidoid multituberculate from the Late Paleocene Nomogen Formation, Inner Mongolia. We examined enamel structures at all hierarchical levels. The samples are treated differently in section orientations and acid preparation and examined using different imaging methods. The results show that, except for preparation artifacts, the crystallites, enamel types, Schmelzmuster and dentition types of Lambdopsalis are relatively consistent in all permanent teeth, but the prism type, including the prism shape, size and density, may vary in different portions of a single tooth or among different teeth of an individual animal. The most common Schmelzmuster of the permanent teeth in Lambdopsalis is a combination of radial enamel in the inner and middle layers, aprismatic enamel in the outer layer, and irregular decussations in tooth crown area with great curvature. The prism seam is another comparably stable characteristic that may be a useful feature for multituberculate taxonomy. The systematic documentation of enamel structures in Lambdopsalis may be generalized for the enamel microstructure study, and thus for taxonomy and phylogenetic reconstruction, of multituberculates and even informative for the enamel study of

A simple rule governs the evolution and development of hominin tooth size.

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Evans, Alistair R; Daly, E Susanne; Catlett, Kierstin K; Paul, Kathleen S; King, Stephen J; Skinner, Matthew M; Nesse, Hans P; Hublin, Jean-Jacques; Townsend, Grant C; Schwartz, Gary T; Jernvall, Jukka

2016-02-25

The variation in molar tooth size in humans and our closest relatives (hominins) has strongly influenced our view of human evolution. The reduction in overall size and disproportionate decrease in third molar size have been noted for over a century, and have been attributed to reduced selection for large dentitions owing to changes in diet or the acquisition of cooking. The systematic pattern of size variation along the tooth row has been described as a 'morphogenetic gradient' in mammal, and more specifically hominin, teeth since Butler and Dahlberg. However, the underlying controls of tooth size have not been well understood, with hypotheses ranging from morphogenetic fields to the clone theory. In this study we address the following question: are there rules that govern how hominin tooth size evolves? Here we propose that the inhibitory cascade, an activator-inhibitor mechanism that affects relative tooth size in mammals, produces the default pattern of tooth sizes for all lower primary postcanine teeth (deciduous premolars and permanent molars) in hominins. This configuration is also equivalent to a morphogenetic gradient, finally pointing to a mechanism that can generate this gradient. The pattern of tooth size remains constant with absolute size in australopiths (including Ardipithecus, Australopithecus and Paranthropus). However, in species of Homo, including modern humans, there is a tight link between tooth proportions and absolute size such that a single developmental parameter can explain both the relative and absolute sizes of primary postcanine teeth. On the basis of the relationship of inhibitory cascade patterning with size, we can use the size at one tooth position to predict the sizes of the remaining four primary postcanine teeth in the row for hominins. Our study provides a development-based expectation to examine the evolution of the unique proportions of human teeth.

Apical Revascularization after Delayed Tooth Replantation: An Unusual Case

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Marília Pacífico Lucisano

2016-01-01

Full Text Available The aim of this paper is to present the clinical and radiological outcome of the treatment involving a delayed tooth replantation after an avulsed immature permanent incisor, with a follow-up of 1 year and 6 months. An 8-year-old boy was referred after dental trauma that occurred on the previous day. The permanent maxillary right central incisor (tooth 11 had been avulsed. The tooth was hand-held during endodontic therapy and an intracanal medication application with calcium hydroxide-based paste was performed. An apical plug with mineral trioxide aggregate (MTA was introduced into the apical portion of the canal. When the avulsed tooth was replanted with digital pressure, a blood clot had formed within the socket, which moved the MTA apical plug about 2 mm inside of the root canal. These procedures developed apical revascularization, which promoted a successful endodontic outcome, evidenced by apical closure, slight increase in root length, and absence of signs of external root resorption, during a follow-up of 1 year and 6 months.

The randomized shortened dental arch study: tooth loss over five years.

Science.gov (United States)

Walter, M H; Hannak, W; Kern, M; Mundt, T; Gernet, W; Weber, A; Wöstmann, B; Stark, H; Werner, D; Hartmann, S; Range, U; Jahn, F; Passia, N; Pospiech, P; Mitov, G; Brückner, J; Wolfart, S; Busche, E; Luthardt, R G; Heydecke, G; Marré, B

2013-04-01

The study was designed to provide clinical outcome data for two treatments of the shortened dental arch (SDA). In a multicenter randomized controlled clinical trial, patients with complete molar loss in one jaw were provided with either a partial removable dental prosthesis (PRDP) retained with precision attachments or treated according to the SDA concept preserving or restoring a premolar occlusion. No implants were placed. The primary outcome was tooth loss. Of 152 treated patients, 132 patients reached the 5-year examination. Over 5 years, 38 patients experienced tooth loss. For the primary outcome tooth loss, the Kaplan-Meier survival rates at 5 years were 0.74 (95% CI 0.64, 0.84) in the PRDP group and 0.74 (95% CI 0.63, 0.85) in the SDA group. For tooth loss in the study jaw, the survival rates at 5 years were 0.88 (95% CI 0.80, 0.95) in the PRDP group and 0.84 (95% CI 0.74, 0.93) in the SDA group. The differences were not significant. No Cox regression models of appropriate fit explaining tooth loss on the patient level could be found. The overall treatment goals of a sustainable oral rehabilitation and the avoidance of further tooth loss over longer periods were not reliably achievable. The influence of the type of prosthetic treatment on tooth loss might have been overestimated. Regarding our results, the patient's view will gain even more importance in the clinical decision between removable and fixed restorations in SDAs.

Minimum intervention dentistry and the management of tooth wear in general practice.

Science.gov (United States)

Meyers, I A

2013-06-01

The incidence of tooth wear, or non-carious tooth surface loss (NCTSL), is increasing and oral rehabilitation of patients with non-carious tooth loss requires strategies that address all the factors relevant to the aetiology and pathogenesis of the condition. The multifactorial nature of tooth wear and the variability in its clinical presentation provides treatment challenges for the clinician and successful management must be more than just restoration. Management must include an appropriate mix of preventive and restorative strategies and an understanding that long-term restorative success is affected by the patient's oral environment, and how diet, lifestyle and medical status can modify this environment. Ultimately, the success of any restorative intervention is very dependent on the stability of the oral environment and the condition of the remaining tooth structure. Minimum intervention dentistry (MID) philosophies are ideally suited to tooth wear cases and an overall MID strategy involving diagnosis, recognition and control of predisposing factors, stabilization of the oral environment, remineralization and restoration of the tooth structure, and ongoing maintenance can be implemented. When restorative treatment is required, contemporary materials and techniques are available that can provide cost-effective and conservative restorative alternatives for patients unable to undergo the complex indirect restorative techniques that are both costly and time consuming to implement. These minimally invasive approaches are not only an economically viable solution, but can provide aesthetic and functional rehabilitation and maintain tooth structure as a precursor to more complex restorative options when required. © 2013 Australian Dental Association.

Evaluation of single-tooth implants in the second molar region: a 5-year life-table analysis of a retrospective study.

Science.gov (United States)

Koo, Ki-Tae; Wikesjö, Ulf M E; Park, Jang-Yeol; Kim, Tae-Il; Seol, Yang-Jo; Ku, Young; Rhyu, In-Chul; Chung, Chong-Pyoung; Lee, Yong-Moo

2010-09-01

To our knowledge, no study has evaluated the success or survival rate of single-tooth implants that replaced missing maxillary and mandibular second molars. The purpose of the present study was to evaluate the 1- to 5-year cumulative survival rate (CSR) for single-tooth implants placed in the second molar region and the effects of associated factors. Four hundred eighty-nine patients (298 males and 191 females; age range: 23 to 91 years; mean age: 47 years) who were admitted to the Seoul National University Dental Hospital between March 2003 and July 2008 and treated with single-tooth implants in the second molar region (227 maxillary implants and 294 mandibular implants; total: 521 implants) were included in the study. Thirty-two subjects received two implants each. A 1- to 5-year CSR was calculated using a life-table analysis. A comparison of CSRs between maxillary versus mandibular implants, one-stage versus two-stage implants, short (10 mm) implants, and standard-diameter (or=5.0 mm) implants was performed using Wilcoxon (Gehan) statistics. P CSR was 95.1%. There were no statistically significant differences in CSRs between implants placed in maxillas and mandibles (96.3% versus 94.9%, respectively; P = 0.084), one- and two-stage implants (95.6% versus 94.7%, respectively; P = 0.267), short and long implants (100% versus 95.1%, respectively; P = 0.582), and standard- and wide-diameter implants (93.8% versus 96.8%, respectively; P = 0.065). Within the limitations of the study, the placement of single-tooth implants in the second molar region was an effective and reliable treatment modality. Also, associated factors such as implant diameter, length, and location (the maxilla versus the mandible) may not have an impact on the long-term success of implants.

Functional role of EMMPRIN in the formation and mineralisation of dental matrix in mouse molars.

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Xie, Ming; Xing, Guofang; Hou, Liwen; Bao, Jing; Chen, Yuqing; Jiao, Ting; Zhang, Fuqiang

2015-02-01

Our previous research has shown that the extracellular matrix metalloproteinase inducer (EMMPRIN) is expressed during and may function in the early development of tooth germs. In the present study, we observed the specific expression of EMMPRIN in ameloblasts and odontoblasts during the middle and late stages of tooth germ development using immunohistochemistry. Furthermore, to extend our understanding of the function of EMMPRIN in odontogenesis, we used an anti-EMMPRIN function-blocking antibody to remove EMMPRIN activity in tooth germ culture in vitro. Both the formation and mineralisation of dental hard tissues were suppressed in the tooth germ culture after the abrogation of EMMPRIN. Meanwhile, significant reductions in VEGF, MMP-9, ALPL, ameloblastin, amelogenin and enamelin expression were observed in antibody-treated tooth germ explants compared to control and normal serum-treated explants. The current results illustrate that EMMPRIN may play a critical role in the processing and maturation of the dental matrix.

Erosive tooth wear in children

NARCIS (Netherlands)

Carvalho, T.S.; Lussi, A.; Jaeggi, T.; Gambon, D.L.; Lussi, A.; Ganss, C.

2014-01-01

Erosive tooth wear in children is a common condition. Besides the anatomical differences between deciduous and permanent teeth, additional histological differences may influence their susceptibility to dissolution. Considering laboratory studies alone, it is not clear whether deciduous teeth are

Tooth brushing, tongue cleaning and snacking behaviour of dental technology and therapist students

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Clement C. Azodo

2010-08-01

Full Text Available Objective: To determine the tooth brushing, tongue cleaning and snacking behaviour of dental technology and therapist students. Methods: A descriptive cross-sectional study of students of Federal School of Dental Therapy and Technology Enugu, Nigeria. Self-administered questionnaire was used to obtain information on demography, frequency, duration and technique of tooth brushing and tongue cleaning as well as information on consumption of snacks. Results: A total of 242 students responded. Dental technology students made up 52.5% of the respondents and dental therapist in training made up 47.5%. Majority (63.2% of the respondents considered the strength of tooth brush when purchasing a tooth brush and 78.9% use tooth brushes with medium strength. Seven-tenth (71.9% of the respondents brush their teeth twice daily and 52.1% brush for 3–5 minutes. About one-third (30.2% brush their teeth in front of a mirror. Chewing stick was used by 51.7% of respondents in addition to the use of tooth brush. Tongue cleaning was done by 94.2% with only 9.5% using a tongue cleaner. Only 20.2% reported regular snacks consumption. Nine-tenth (90.4% of respondents were previously involved in educating others, apart from their colleagues, on tooth brushing. Conclusion: This survey revealed that most of the dental therapy and technology students had satisfactory tooth-brushing behaviour. The zeal to educate others about proper tooth brushing revealed in this study suggests that the students may be helpful in oral health promotion.

Energy harvesting from mastication forces via a smart tooth

Science.gov (United States)

Bani-Hani, Muath; Karami, M. Amin

2016-04-01

The batteries of the current pacing devices are relatively large and occupy over 60 percent of the size of pulse generators. Therefore, they cannot be placed in the subtle areas of human body. In this paper, the mastication force and the resulting tooth pressure are converted to electricity. The pressure energy can be converted to electricity by using the piezoelectric effect. The tooth crown is used as a power autonomous pulse generator. We refer to this envisioned pulse generator as the smart tooth. The smart tooth is in the form of a dental implant. A piezoelectric vibration energy harvester is designed and modeled for this purpose. The Piezoelectric based energy harvesters investigated and analyzed in this paper initially includes a single degree of freedom piezoelectric based stack energy harvester which utilizes a harvesting circuit employing the case of a purely resistive circuit. The next step is utilizing and investigating a bimorph piezoelectric beam which is integrated/embedded in the smart tooth implant. Mastication process causes the bimorph beam to buckle or return to unbuckled condition. The transitions results in vibration of the piezoelectric beam and thus generate energy. The power estimated by the two mechanisms is in the order of hundreds of microwatts. Both scenarios of the energy harvesters are analytically modeled. The exact analytical solution of the piezoelectric beam energy harvester with Euler-Bernoulli beam assumptions is presented. The electro-mechanical coupling and the geometric nonlinearities have been included in the model for the piezoelectric beam.

Root canal treatment of mandibular second premolar tooth with taurodontism

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Vujašković Mirjana

2008-01-01

Full Text Available INTRODUCTION Taurodontism is a morphoanatomical change in the shape of a tooth. An enlarged body of a tooth with smaller than usual roots is a characteristic feature. Internal tooth anatomy correlates with this appearance, which means that a taurodontal tooth has a large pulp chamber and apically positioned furcations. This dental anomaly may be associated with different syndromes and congenital discoders. CASE OUTLINE The case report presents the patient of a rare case of taurodontism in the mandibular second premolar with chronic periodontitis. Endodontic treatment was performed after dental history and clinical examination. Special care is required in all segments of endodontic treatment of a taurodontal tooth from the identification orifice, canal exploration, determining working length, cleaning and shaping and obturation of the root canal. Precurved K-file was used for canal exploration and location of the furcation. One mesial and one distal canal with the buccal position were identified in the apical third of the root canal. The working lengths of two canals were determined by radiographic interpretation with two K-files in each canal and verified with the apex locator. During canal instrumentation, the third canal was located in the disto-lingual position. The working length of the third canal was established using the apex locator. CONCLUSION Thorough knowledge of tooth anatomy and its variations can lead to lower percentage of endodontic failure. Each clinical case involving these teeth should be investigated carefully, clinically and radiographically to detect additional root canals. High quality radiographs from different angles and proper instrumentarium improve the quality of endodontic procedure.

Orthodontic tooth movement with clear aligners.

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Drake, Carl T; McGorray, Susan P; Dolce, Calogero; Nair, Madhu; Wheeler, Timothy T

2012-01-01

Clear aligners provide a convenient model to measure orthodontic tooth movement (OTM). We examined the role of in vivo aligner material fatigue and subject-specific factors in tooth movement. Fifteen subjects seeking orthodontic treatment at the University of Florida were enrolled. Results were compared with data previously collected from 37 subjects enrolled in a similar protocol. Subjects were followed prospectively for eight weeks. An upper central incisor was programmed to move 0.5 mm. every two weeks using clear aligners. A duplicate aligner was provided for the second week of each cycle. Weekly polyvinyl siloxane (PVS) impressions were taken, and digital models were fabricated to measure OTM. Initial and final cone beam computed tomography (CBCT) images were obtained to characterize OTM. Results were compared to data from a similar protocol, where subjects received a new aligner biweekly. No significant difference was found in the amount of OTM between the two groups, with mean total OTM of 1.11 mm. (standard deviation (SD) 0.30) and 1.07 mm. (SD 0.33) for the weekly aligner and biweekly control groups, respectively (P = 0.72). Over eight weeks, in two-week intervals, material fatigue does not play a significant role in the rate or amount of tooth movement.

[Early deciduous tooth loss--the mature or immature eruption of their permanent successors].

Science.gov (United States)

Czecholinski, J A; Kahl, B; Schwarze, C W

1994-04-01

On the basis of 147 panoramic radiographs of 49 patients, this study investigated the influence of the premature loss of deciduous teeth on the formation of their permanent successors at the time of their eruption. Furthermore the study investigated the eruptive movement of the successor teeth at the time of eruption. In addition to detecting the accelerated emergence of still immature successor premolars, the study also determined that the extraction ot the deciduous molars before the age of eight years delayed the eruption of the permanent successors given the absence of an infected deciduous tooth with abscess formation. In relation to the eruptive movement of the permanent molars due to the premature loss of the second deciduous molar, the study ascertained a mesial movement of the first permanent molars and an accelerated eruption of the second permanent molars.

Monte Carlo modeling of human tooth optical coherence tomography imaging

International Nuclear Information System (INIS)

Shi, Boya; Meng, Zhuo; Wang, Longzhi; Liu, Tiegen

2013-01-01

We present a Monte Carlo model for optical coherence tomography (OCT) imaging of human tooth. The model is implemented by combining the simulation of a Gaussian beam with simulation for photon propagation in a two-layer human tooth model with non-parallel surfaces through a Monte Carlo method. The geometry and the optical parameters of the human tooth model are chosen on the basis of the experimental OCT images. The results show that the simulated OCT images are qualitatively consistent with the experimental ones. Using the model, we demonstrate the following: firstly, two types of photons contribute to the information of morphological features and noise in the OCT image of a human tooth, respectively. Secondly, the critical imaging depth of the tooth model is obtained, and it is found to decrease significantly with increasing mineral loss, simulated as different enamel scattering coefficients. Finally, the best focus position is located below and close to the dental surface by analysis of the effect of focus positions on the OCT signal and critical imaging depth. We anticipate that this modeling will become a powerful and accurate tool for a preliminary numerical study of the OCT technique on diseases of dental hard tissue in human teeth. (paper)

Elderly complete denture wearers: a social approach to tooth loss.

Science.gov (United States)

Papadaki, Eftychia; Anastassiadou, Vassiliki

2012-06-01

To correlate emotional reactions to tooth loss with denture satisfaction attributes in elderly complete denture wearers. Total tooth loss is a serious life event, and poor oral health has an impact on daily life. Edentulism treated by rehabilitation with dentures can have a positive effect on patients' self-image and social behaviour. A group of 80 edentulous subjects undergoing routine prosthetic care in a Greek Department of Prosthetic Dentistry were interviewed using two structured questionnaires. The first questionnaire explored reactions to tooth loss, whereas the second measured their subjective experience of complete dentures. The responses to both questionnaires were compared using the statistical package SPSS v.17. The results showed significant correlation between aspects of tooth loss experience and complete denture satisfaction. Despite the fact that a substantial proportion of patients were satisfied with their complete dentures, some patients experienced increased social and psychological problems related to their edentulousness and the wearing of complete dentures. The aesthetic and functional aspects of complete dentures affected both patients' social behaviour and self-confidence. Total tooth loss was not only reflected in patient's social behaviour and self-image, but it had a complex and multifaceted impact on satisfaction from complete dentures. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

Design and implementation of therapeutic ultrasound generating circuit for dental tissue formation and tooth-root healing.

Science.gov (United States)

Woon Tiong Ang; Scurtescu, C; Wing Hoy; El-Bialy, T; Ying Yin Tsui; Jie Chen

2010-02-01

Biological tissue healing has recently attracted a great deal of research interest in various medical fields. Trauma to teeth, deep and root caries, and orthodontic treatment can all lead to various degrees of root resorption. In our previous study, we showed that low-intensity pulsed ultrasound (LIPUS) enhances the growth of lower incisor apices and accelerates their rate of eruption in rabbits by inducing dental tissue growth. We also performed clinical studies and demonstrated that LIPUS facilitates the healing of orthodontically induced teeth-root resorption in humans. However, the available LIPUS devices are too large to be used comfortably inside the mouth. In this paper, the design and implementation of a low-power LIPUS generator is presented. The generator is the core of the final intraoral device for preventing tooth root loss and enhancing tooth root tissue healing. The generator consists of a power-supply subsystem, an ultrasonic transducer, an impedance-matching circuit, and an integrated circuit composed of a digital controller circuitry and the associated driver circuit. Most of our efforts focus on the design of the impedance-matching circuit and the integrated system-on-chip circuit. The chip was designed and fabricated using 0.8- ¿m high-voltage technology from Dalsa Semiconductor, Inc. The power supply subsystem and its impedance-matching network are implemented using discrete components. The LIPUS generator was tested and verified to function as designed and is capable of producing ultrasound power up to 100 mW in the vicinity of the transducer's resonance frequency at 1.5 MHz. The power efficiency of the circuitry, excluding the power supply subsystem, is estimated at 70%. The final products will be tailored to the exact size of teeth or biological tissue, which is needed to be used for stimulating dental tissue (dentine and cementum) healing.

Kinematics modeling and experimentation of the multi-manipulator tooth-arrangement robot for full denture manufacturing.

Science.gov (United States)

Zhang, Yong-de; Jiang, Jin-gang; Liang, Ting; Hu, Wei-ping

2011-12-01

Artificial teeth are very complicated in shape, and not easy to be grasped and manipulated accurately by a single robot. The method of tooth-arrangement by multi-manipulator for complete denture manufacturing proposed in this paper. A novel complete denture manufacturing mechanism is designed based on multi-manipulator and dental arch generator. Kinematics model of the multi-manipulator tooth-arrangement robot is built by analytical method based on tooth-arrangement principle for full denture. Preliminary experiments on tooth-arrangement are performed using the multi-manipulator tooth-arrangement robot prototype system. The multi-manipulator tooth-arrangement robot prototype system can automatically design and manufacture a set of complete denture that is suitable for a patient according to the jaw arch parameters. The experimental results verified the validity of kinematics model of the multi-manipulator tooth-arrangement robot and the feasibility of the manufacture strategy of complete denture fulfilled by multi-manipulator tooth-arrangement robot.

Outcome of Endodontically Treated Teeth Diagnosed With Cracked Tooth

Science.gov (United States)

2015-06-01

However, variable symptoms complicate the diagnosis (9). In a study of 32 patients presenting with diffuse longstanding orofacial pain eventually...883-92. 22)Byrnjulsen A, Fristad I, Grevstad T, Hals-Kvinnsland I. Incompletely fractured teeth associated with diffuse longstanding orofacial pain ...cracked tooth is highly associated with discomfort. Patients often describe a momentary, sudden, sharp, lancinating pain that results in continuous tooth

REPLACEMENT CONTROL OF INNOVATION MANAGERS: ORGANIZATIONAL AND ECONOMIC ASPECTS

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E. V. Gurina

2011-01-01

Full Text Available The paper substantiates phases of specialists’ replacement ensuring innovation development of the national economy in Belarus, i.e. managers of innovation activity. Realization of replacement phases is presented within the system consisting of four blocks – objective, managing, controllable and providing. Analysis results of the current state of the innovation activity managers replacement system reveal main problems in interaction of its basic agents. The paper considers solution of specified problems in the context of formation of organizational and economic approaches to managing the innovation activity managers replacement system which presupposes modernization of organizational interrelations between state- run public authorities in the managing block and micro-incentive structures in the controllable block as well as the usage of the process approach in every phase of the replacement process. 

Technical Modifications of Tooth-borne Distraction Device for Anterior Maxillary Distraction in Cleft Patients

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Dhivakar Selvaraj

2014-01-01

Full Text Available The tooth-borne distractor gained popularity for anterior maxillary distraction because of the effective treatment outcome, no need for external fixation, noninvasive, less chewing difficulty, social tolerance and economical. Tooth-borne distractor device needs modification in terms of maxillary deficiency, tooth position, retained deciduous tooth, and fistula. Hence, we recommend the following modifications in certain circumstances for the successful treatment outcome.

Development of the nervus terminalis in mammals including toothed whales and humans.

Science.gov (United States)

Oelschläger, H A; Buhl, E H; Dann, J F

1987-01-01

The early ontogenesis and topography of the mammalian terminalis system was investigated in 43 microslide series of toothed whale and human embryos and fetuses. In early embryonal stages the development of the nasal pit, the olfacto-terminalis placode, and the olfactory bulb anlage is rather similar in toothed whales and humans. However, toothed whales do not show any trace of the vomeronasalis complex. In early fetal stages the olfactory bulb anlage in toothed whales is reduced and leaves the isolated future terminalis ganglion (ganglia) which contains the greatest number of cells within Mammalia. The ganglion is connected with the nasal mucosa via peripheral fiber bundles and with the telencephalon via central terminalis rootlets. The functional implications of the terminalis system in mammals and its evolution in toothed whales are discussed. Obviously, the autonomic component has been enlarged in the course of perfect adaptation to an aquatic environment.

Recording and quantification of ultrasonic echolocation clicks from free-ranging toothed whales

DEFF Research Database (Denmark)

Madsen, Peter Teglberg; Wahlberg, Magnus

2007-01-01

Toothed whales produce short, ultrasonic clicks of high directionality and source level to probe their environment acoustically. This process, termed echolocation, is to a large part governed by the properties of the emitted clicks. Therefore derivation of click source parameters from free......-ranging animals is of increasing importance to understand both how toothed whales use echolocation in the wild and how they may be monitored acoustically. This paper addresses how source parameters can be derived from free-ranging toothed whales in the wild using calibrated multi-hydrophone arrays and digital...... of discrete versions of toothed whale clicks that are meaningful in a biosonar context....

Dens evaginatus and dens invaginatus in a double tooth: A rare case report

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Gaurav Sharma

2015-01-01

Full Text Available The presence of dens invaginatus (DI and dens evaginatus (DE on same tooth is a rare phenomenon. However, when these dental anomalies occur on a double tooth, it becomes an extremely rare phenomenon. The authors report a rare case of DI and DE on fused permanent maxillary central incisor with supernumerary tooth in a 40-year-old male. The present article also focuses on the differentiating fusion from gemination and also reviews preventive and management strategies for tooth with complex dental anatomy.

Bis-enoxacin Inhibits Bone Resorption and Orthodontic Tooth Movement

Science.gov (United States)

Toro, E.J.; Zuo, J.; Guiterrez, A.; La Rosa, R.L.; Gawron, A.J.; Bradaschia-Correa, V.; Arana-Chavez, V.; Dolce, C.; Rivera, M.F.; Kesavalu, L.; Bhattacharyya, I.; Neubert, J.K.; Holliday, L.S.

2013-01-01

Enoxacin inhibits binding between the B-subunit of vacuolar H+-ATPase (V-ATPase) and microfilaments, and also between osteoclast formation and bone resorption in vitro. We hypothesized that a bisphosphonate derivative of enoxacin, bis-enoxacin (BE), which was previously studied as a bone-directed antibiotic, might have similar activities. BE shared a number of characteristics with enoxacin: It blocked binding between the recombinant B-subunit and microfilaments and inhibited osteoclastogenesis in cell culture with IC50s of about 10 µM in each case. BE did not alter the relative expression levels of various osteoclast-specific proteins. Even though tartrate-resistant acid phosphatase 5b was expressed, proteolytic activation of the latent pro-enzyme was inhibited. However, unlike enoxacin, BE stimulated caspase-3 activity. BE bound to bone slices and inhibited bone resorption by osteoclasts on BE-coated bone slices in cell culture. BE reduced the amount of orthodontic tooth movement achieved in rats after 28 days. Analysis of these data suggests that BE is a novel anti-resorptive molecule that is active both in vitro and in vivo and may have clinical uses. Abbreviations: BE, bis-enoxacin; V-ATPase, vacuolar H+-ATPase; TRAP, tartrate-resistant acid phosphatase; αMEM D10, minimal essential media, alpha modification with 10% fetal bovine serum; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; RANKL, receptor activator of nuclear factor kappa B-ligand; NFATc1, nuclear factor of activated T-cells; ADAM, a disintegrin and metalloprotease domain; OTM, orthodontic tooth movement. PMID:23958763

Diagnostics of power transmissions system with tooth gear

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Grzegorz WOJNAR

2008-01-01

Full Text Available This paper presents results of laboratory tests that were aimed at detecting early stages of various faults in toothed wheels by measurement and analysis of transverse vibration speed of the transmission gear shafts. In experimental investigation, cracking of the root tooth and chipping of the tooth were detected. The laser vibrometer Ometron VH300+ was used for non-contact measurement of shaft transversal vibration speed. Gear vibrations were recorded in selected points of gear housing and gear shafts at different speeds and gear loads. Results were analyzed and compared but in this paper is presented only selected examples. This paper shows that on the basis of the transverse vibration speed of transmission gear shafts, it is possible to detect defects at an earlier stage than on the basis of the housing vibration accelerations. In the case of measuring gear shaft vibration velocity, the way of the signal generated by the defect of a gear wheel (or bearing is shortened as well as the influence of composed transmittance of the bearing-gear housing system is eliminated. WV time-frequency analysis and complex continuous wavelet transformations were used for detection. The authors introduced a measure of local tooth damage, which was proportional to the size of damage. The results of research presented in this paperconfirmed that the defect's measure is very sensitive to the development of teeth faults.

On optimization of internal/external spur gears tooth bending strength

DEFF Research Database (Denmark)

Pedersen, Niels Leergaard

2014-01-01

level at the tooth root. As with most machine elements the design/geometry is defined in standards (ISO). The present work focuses on changing the tooth root design of both external and internal gears, in order to improve the stress concentration factor. The design changes made are compliant...

Incisal tooth wear and self-reported TMD pain in children and adolescents.

Science.gov (United States)

Hirsch, Christian; John, Mike T; Lobbezoo, Frank; Setz, Juergen M; Schaller, Hans-Guenter

2004-01-01

Incisal tooth wear may be a sign of long-term bruxing behavior. Bruxism is purported to be a risk factor for temporomandibular disorders (TMD). The aim of this population-based cross-sectional study was to determine if anterior tooth wear is associated with the self-report of TMD pain in children and adolescents. In a population sample of 1,011 children and adolescents (mean age 13.1 years, range 10 to 18 years; female 52%; response rate 85%), TMD cases were defined as subjects reporting pain in the face, jaw muscles, and temporomandibular joint during the last month according to RDC/TMD. All other subjects were considered controls. Incisal tooth wear was assessed in the clinical examination using a 0 to 2 scale (no wear, enamel wear, dentin wear) for every anterior permanent tooth. The mean wear score for the individuals was categorized into 0, 0.01 to 0.20, 0.21 to 0.40, and 0.41+. A multiple logistic regression analysis, controlling for the effects of age and gender, analyzed the association between the categorized summary wear score and TMD. Specifically, the hypothesis of a trend between higher tooth wear scores and higher risk of TMD was tested. An odds ratio of 1.1 indicated, after adjusting for gender and age, no statistically significantly higher risk of TMD pain with higher tooth wear scores. Incisal tooth wear was not associated with self-reported TMD pain in 10- to 18-year-old subjects.

Characteristics and formation mechanism for stainless steel fiber with periodic micro-fins

Science.gov (United States)

Tang, Tao; Wan, Zhenping; Lu, Longsheng; Tang, Yong

2016-05-01

Metal fibers have been widely used in many industrial applications due to their unique advantages. In certain applications, such as catalyst supports or orthopedic implants, a rough surface or tiny outshoots on the surface of metal fibers to increase surface area are needed. However, it has not been concerned about the surface morphologies of metal fiber in the current research of metal fiber manufacturing. In this paper, a special multi-tooth tool composed of a row of triangular tiny teeth is designed. The entire cutting layer of multi-tooth tool bifurcates into several thin cutting layers due to tiny teeth involved in cutting. As a result, several stainless steel fibers with periodic micro-fins are produced simultaneously. Morphology of periodic micro-fins is found to be diverse and can be classified into three categories: unilateral plane, unilateral tapering and bilateral. There are two forming mechanisms for the micro-fins. One is that periodic burrs remained on the free side of cutting layer of a tiny tooth create micro-fins of stainless steel fiber produced by the next neighboring tiny tooth; the other is that the connections between two fibers stuck together come to be micro-fins if the two fibers are finally detached. Influence of cutting conditions on formation of micro-fins is investigated. Experimental results show that cutting depth has no significant effect on micro-fin formation, high cutting speed is conducive to micro-fin formation, and feed should be between 0.12 mm/r and 0.2 mm/r to reliably obtain stainless steel fiber with micro-fins. This research presents a new pattern of stainless steel fiber characterized by periodic micro-fins formed on the edge of fiber and its manufacturing method.

Unique case of a geminated supernumerary tooth with trifid crown

International Nuclear Information System (INIS)

Ather, Amber; Ather, Hunaiza; Sheth, Sanket Milan; Muliya, Vidya Saraswathi

2012-01-01

Gemination, a relatively uncommon dental anomaly, is characterized by its peculiar representation as a tooth with a bifid crown and a common root and root canal. It usually occurs in primary dentition. To come across gemination in a supernumerary tooth is a rare phenomenon. The purpose of this paper is to present a unique case of hyperdontia wherein gemination in an impacted supernumerary tooth resulted in a trifid crown unlike the usual bifid crown. The role of conventional radiographs as well as computed tomography, to accurately determine the morphology and spatial location, and to arrive at a diagnosis, is also emphasized in this paper.

Assessment of the progression of tooth wear on dental casts

NARCIS (Netherlands)

Vervoorn-Vis, G.M.G.J.; Wetselaar, P.; Koutris, M.; Visscher, C.M.; Evälahti, M.; Ahlberg, J.; Lobbezoo, F.

2015-01-01

Many methods are available for the grading of tooth wear, but their ability to assess the progression of wear over time has not been studied frequently. The aim was to assess whether the occlusal/incisal grading scale of the Tooth Wear Evaluation System (TWES) was sensitive enough for the detection

Effect of Orthodontic Tooth Movement on Salivary Aspartate Aminotransferase Activity

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Steiven Adhitya

2013-07-01

Full Text Available 72 1024x768 Aspartate aminotransferase is one of biological indicator in gingival crevicular fluid (CGF. Force orthodontic application could increase activity of aspartate aminotransferase in CGF. However, the increase activity of aspartate aminotransferase in saliva due to orthodontic force and its correlation between aspartate aminotransferase activity and tooth movement remains unclear. Objectives: To evaluate application orthodontic force on the aspartate aminotransferase activity in saliva based on the duration of force and finding correlation between tooth movement and aspartate aminotransferase activity. Methods: Twenty saliva samples collected before extraction of first premolar, at the time of force application for canine retraction and after force application. The canines retraction used 100 grams of interrupted force (module chain for thirty days. The collection of saliva and the measurement of tooth movement were carried out 1 day, 7 days, 14 days, 21 days, and 28 days after force application. The measurement of aspartate aminotransferase activity in saliva was done using spectrophotometer. Results: Application of orthodontic force influences the salivary aspartate aminotransferase activity (F=25.290, p=0.000. Furthermore, tooth movement correlated with aspartate aminotransferase activity (F=0.429, p=0.000. Conclusion: Aspartate aminotransferase activity could be used as tooth movement indicator that related to the duration of force application.DOI : 10.14693/jdi.v20i1.128

A review of heat transfer in human tooth--experimental characterization and mathematical modeling.

Science.gov (United States)

Lin, Min; Xu, Feng; Lu, Tian Jian; Bai, Bo Feng

2010-06-01

With rapid advances in modern dentistry, high-energy output instruments (e.g., dental lasers and light polymerizing units) are increasingly employed in dental surgery for applications such as laser assisted tooth ablation, bleaching, hypersensitivity treatment and polymerization of dental restorative materials. Extreme high temperature occurs within the tooth during these treatments, which may induce tooth thermal pain (TTP) sensation. Despite the wide application of these dental treatments, the underlying mechanisms are far from clear. Therefore, there is an urgent need to better understand heat transfer (HT) process in tooth, thermally induced damage of tooth, and the corresponding TTP. This will enhance the design and optimization of clinical treatment strategies. This paper presents the state-of-the-art of the current understanding on HT in tooth, with both experimental study and mathematical modeling reviewed. Limitations of the current experimental and mathematical methodologies are discussed and potential solutions are suggested. Interpretation of TTP in terms of thermally stimulated dentinal fluid flow is also discussed. Copyright (c) 2010 Academy of Dental Materials. All rights reserved.

Conversion from tooth enamel dose to organ doses for electron spin resonance dosimetry

International Nuclear Information System (INIS)

Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Saito, Kimiaki; Hamada, Tatsuji

2002-01-01

Conversion from tooth enamel dose to organ doses was analyzed to establish a method of retrospective individual dose assessment against external photon exposure by electron spin resonance (ESR) dosimetry. Dose to tooth enamel was obtained by Monte Carlo calculations using a modified MIRD-type phantom with a teeth part. The calculated tooth enamel doses were verified by measurements with thermo-luminescence dosimeters inserted in a physical head phantom. Energy and angular dependences of tooth enamel dose were compared with those of other organ doses. Additional Monte Carlo calculations were performed to study the effect of human model on the tooth enamel dose with a voxel-type phantom, which was based on computed tomography images of the physical phantom. The data derived with the modified MIRD-type phantom were applied to convert from tooth enamel dose to organ doses against external photon exposure in a hypothesized field, where scattered radiation was taken into account. The results indicated that energy distribution of photons incident to a human body is required to evaluate precisely an individual dose based on ESR dosimetry for teeth. (author)

Clinical management of a fused upper premolar with supernumerary tooth: a case report

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Kyu-Min Cho

2014-11-01

Full Text Available n dentistry, the term 'fusion' is used to describe a developmental disorder of dental hard tissues. In the permanent dentition, fusion of a normal tooth and a supernumerary tooth usually involves the incisors or canines. However, a few cases of fusion involving premolars have also been reported to date. We present a rare case in which fusion of the maxillary left second premolar and a supernumerary tooth in a 13-year-old girl was diagnosed using cone beam computed tomography (CBCT, Alphard-3030, Asahi Roentgen Ind. Co., Ltd.. The tooth was bicuspidized after routine nonsurgical root canal treatment, and the separated teeth underwent appropriate restoration procedures. The second premolar and supernumerary tooth remained asymptomatic without any signs of inflammation after a follow-up period of 9 years. Identification of anatomical anomalies is important for treatment in cases involving fusion with supernumerary tooth, and therefore the microscopic examinations and CBCT are essential for the diagnosis. Fused teeth can be effectively managed by the comprehensive treatment which includes both endodontic and periodontal procedures.

Corticotomy affects both the modus and magnitude of orthodontic tooth movement

DEFF Research Database (Denmark)

Verna, Carlalberta; Cattaneo, Paolo; Dalstra, Michel

2017-01-01

OBJECTIVE: To analyze whether the decreased bone density due to the manipulation of bone remodeling rate has an influence on the type of the planned tooth movement. MATERIALS AND METHODS: A finite element model of a lower incisor has been developed. The density of the alveolar bone surrounding th......: A decreased bone density influences not only the amount of tooth movement, but also its type. This study suggests that the moment-to-force ratios used in conventional orthodontics should be modified in case of techniques that decrease bone density to enhance tooth movement rate....

Tooth damage in captive orcas (Orcinus orca).

Science.gov (United States)

Jett, John; Visser, Ingrid N; Ventre, Jeffrey; Waltz, Jordan; Loch, Carolina

2017-12-01

Tooth damage as a result of oral stereotypies is evident in captive orca, yet little research on the topic exists. This study examines the associations between dental pathology, sex, facility, duration of captivity and other factors in captive orca. We evaluated mandibular and maxillary teeth from dental images of 29 captive orca owned by a US-based theme park. Each tooth was scored for coronal wear, wear at or below gum line and bore holes. Fractured and missing teeth were also noted. Summary statistics described the distribution and severity of pathologies; inferential statistics examined how pathologies differed between sexes, between wild-captured and captive-born orcas and between captive orca at four facilities. We also evaluated how dental pathology and duration of captivity were related. Approximately 24% of whales exhibited "major" to "extreme" mandibular coronal tooth wear, with coronal wear and wear at or below gum line highly correlated. More than 60% of mandibular teeth 2 and 3 exhibited fractures. Bore holes were observed primarily among anterior mandibular teeth, with more than 61% of teeth 2 and 3 bearing evidence of having been drilled. Four of five orca with the highest age-adjusted tooth pathology indices were captive-born. Various dental pathologies were observed across all whales, with pathologies beginning at a young age. Oral stereotypies exhibited by captive orca contributed to the observed dental damage. By making dental and health records of captive whales publicly available, the theme park industry is uniquely positioned to provide further insight into dental pathology and resultant health consequences in captive orca. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phenotypic spectrum of dynamin 2 mutations in Charcot-Marie-Tooth neuropathy

NARCIS (Netherlands)

Claeys, Kristl G.; Züchner, Stephan; Kennerson, Marina; Berciano, José; Garcia, Antonio; Verhoeven, Kristien; Storey, Elsdon; Merory, John R.; Bienfait, Henriette M. E.; Lammens, Martin; Nelis, Eva; Baets, Jonathan; de Vriendt, Els; Berneman, Zwi N.; de Veuster, Ilse; Vance, Jefferey M.; Nicholson, Garth; Timmerman, Vincent; de Jonghe, Peter

2009-01-01

Dominant intermediate Charcot-Marie-Tooth neuropathy type B is caused by mutations in dynamin 2. We studied the clinical, haematological, electrophysiological and sural nerve biopsy findings in 34 patients belonging to six unrelated dominant intermediate Charcot-Marie-Tooth neuropathy type B

Crocodyliform feeding traces on juvenile ornithischian dinosaurs from the Upper Cretaceous (Campanian Kaiparowits Formation, Utah.

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Clint A Boyd

Full Text Available Crocodyliforms serve as important taphonomic agents, accumulating and modifying vertebrate remains. Previous discussions of Mesozoic crocodyliform feeding in terrestrial and riverine ecosystems have often focused on larger taxa and their interactions with equally large dinosaurian prey. However, recent evidence suggests that the impact of smaller crocodyliforms on their environments should not be discounted. Here we present direct evidence of feeding by a small crocodyliform on juvenile specimens of a 'hypsilophodontid' dinosaur from the Upper Cretaceous (Campanian Kaiparowits Formation of southern Utah. Diagnostic crocodyliform bite marks present on a left scapula and a right femur, as well as a partial probable crocodyliform tooth crown (ovoid in cross-section preserved within a puncture on the right femur, comprise the bulk of the feeding evidence. Computed tomography scans of the femoral puncture reveal impact damage to the surrounding bone and that the distal tip of the embedded tooth was missing prior to the biting event. This is only the second reported incidence of a fossil crocodyliform tooth being found embedded directly into prey bone. These bite marks provide insight into the trophic interactions of the ecosystem preserved in the Kaiparowits Formation. The high diversity of crocodyliforms within this formation may have led to accentuated niche partitioning, which seems to have included juvenile dinosaurian prey.

Graphene oxide scaffold accelerates cellular proliferative response and alveolar bone healing of tooth extraction socket.

Science.gov (United States)

Nishida, Erika; Miyaji, Hirofumi; Kato, Akihito; Takita, Hiroko; Iwanaga, Toshihiko; Momose, Takehito; Ogawa, Kosuke; Murakami, Shusuke; Sugaya, Tsutomu; Kawanami, Masamitsu

2016-01-01

Graphene oxide (GO) consisting of a carbon monolayer has been widely investigated for tissue engineering platforms because of its unique properties. For this study, we fabricated a GO-applied scaffold and assessed the cellular and tissue behaviors in the scaffold. A preclinical test was conducted to ascertain whether the GO scaffold promoted bone induction in dog tooth extraction sockets. For this study, GO scaffolds were prepared by coating the surface of a collagen sponge scaffold with 0.1 and 1 µg/mL GO dispersion. Scaffolds were characterized using scanning electron microscopy (SEM), physical testing, cell seeding, and rat subcutaneous implant testing. Then a GO scaffold was implanted into a dog tooth extraction socket. Histological observations were made at 2 weeks postsurgery. SEM observations show that GO attached to the surface of collagen scaffold struts. The GO scaffold exhibited an interconnected structure resembling that of control subjects. GO application improved the physical strength, enzyme resistance, and adsorption of calcium and proteins. Cytocompatibility tests showed that GO application significantly increased osteoblastic MC3T3-E1 cell proliferation. In addition, an assessment of rat subcutaneous tissue response revealed that implantation of 1 µg/mL GO scaffold stimulated cellular ingrowth behavior, suggesting that the GO scaffold exhibited good biocompatibility. The tissue ingrowth area and DNA contents of 1 µg/mL GO scaffold were, respectively, approximately 2.5-fold and 1.4-fold greater than those of the control. Particularly, the infiltration of ED2-positive (M2) macrophages and blood vessels were prominent in the GO scaffold. Dog bone-formation tests showed that 1 µg/mL GO scaffold implantation enhanced bone formation. New bone formation following GO scaffold implantation was enhanced fivefold compared to that in control subjects. These results suggest that GO was biocompatible and had high bone-formation capability for the scaffold

Generation of gear tooth surfaces by application of CNC machines

Science.gov (United States)

Litvin, F. L.; Chen, N. X.

1994-01-01

This study will demonstrate the importance of application of computer numerically controlled (CNC) machines in generation of gear tooth surfaces with new topology. This topology decreases gear vibration and will extend the gear capacity and service life. A preliminary investigation by a tooth contact analysis (TCA) program has shown that gear tooth surfaces in line contact (for instance, involute helical gears with parallel axes, worm gear drives with cylindrical worms, etc.) are very sensitive to angular errors of misalignment that cause edge contact and an unfavorable shape of transmission errors and vibration. The new topology of gear tooth surfaces is based on the localization of bearing contact, and the synthesis of a predesigned parabolic function of transmission errors that is able to absorb a piecewise linear function of transmission errors caused by gear misalignment. The report will describe the following topics: description of kinematics of CNC machines with six degrees of freedom that can be applied for generation of gear tooth surfaces with new topology. A new method for grinding of gear tooth surfaces by a cone surface or surface of revolution based on application of CNC machines is described. This method provides an optimal approximation of the ground surface to the given one. This method is especially beneficial when undeveloped ruled surfaces are to be ground. Execution of motions of the CNC machine is also described. The solution to this problem can be applied as well for the transfer of machine tool settings from a conventional generator to the CNC machine. The developed theory required the derivation of a modified equation of meshing based on application of the concept of space curves, space curves represented on surfaces, geodesic curvature, surface torsion, etc. Condensed information on these topics of differential geometry is provided as well.

Relationship and inter observer agreement of tooth and face forms in a Saudi subpopulation.

Science.gov (United States)

Habib, Syed Rashid; Shiddi, Ibraheem Al; Al-Sufyani, Mohammed D; Althobaiti, Fahad A

2015-04-01

To determine the relationship of tooth form with the face form by different observers and further investigate the inter observer agreement on tooth forms, face forms, their relationship among male Saudis. A comparative cross-sectional study. Department of Prosthodontics, College of Dentistry, King Saud University, Riyadh, KSA, from February till August 2013. Ninety four male participants aged 18 - 35 years were randomly recruited for the study. Full-face and anterior teeth (intraoral) digital photographs in the frontal plane were recorded. The outline tracings of the face and the tooth were obtained using Autocad (version 2010) software. The outline of the tooth was enlarged proportionately, without altering the length to width ratio to fit the face outline. The outlines were then evaluated visually by 6 prosthodontists and results were tabulated. The most common type of face form (49.65%) and tooth form (56.38%) was square tapering. Using the visual method, a good relationship (31.41%), moderate relationship (35.31%), weak relationship (19.68%) and no relationship (13.65%) between the tooth form and face form was found by the observers. Overall kappa for inter observer agreement on face form, tooth form and their relationship was 0.24, 0.17 and 0.26 respectively. The kappa values showed a fair agreement between the observers. The study results indicated that there was no highly defined relationship between the tooth form and face form in the studied Saudi subpopulation. A fair agreement was found between the observers for classifying the tooth forms, face froms and their relationship.

Surgical treatments of the impacted canine tooth in young dogs

International Nuclear Information System (INIS)

Amimoto, A.; Iwamoto, S.; Hachimura, H.; Sasaki, K.; Taura, Y.; Nakama, S.; Yamanouchi, T.

1993-01-01

Surgical treatments of the impacted canine tooth were carried out in 8 young dogs, and the results were successful in 12 out of 14 cases (85.7%). The treatments consisting of surgical correction by immediate tipping movement, fenestration of the gingiva, and removal of the impacted tooth, were applied to 14 cases radiographically showing the immature tooth root and no abnormalities in the tooth root or alveolar bone. Impacted teeth were seen in 8 regions of the maxilla and 6 regions of the mandible. Mesioversion was seen in almost all maxillary impacted teeth, while linguoversion or lingual mesioversion in all mandibular cases. Surgical correction was carried out by immediate tipping movement after removal of the retained deciduous canine with or without resection of the alveolar bone. Fixation of the moved teeth was done using a wedge made from the deciduous canine root, which was driven into the vacant alveolar cavity after moving. An additional fixation using a steel wire and/or self-curing resin was done, if necessary

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.

AUTOGENOUS TOOTH TRANSPLANTATION IN ADULT ...

African Journals Online (AJOL)

drclement

ABSTRACT. A case of autotransplantation of a tooth in a 26 year old female African cleft palate patient is reported. This case report emphasizes the possibility and success of autotransplantation in our centre, it also emphasizes that transplantation is only technique sensitive but less equipment sensitive. It further stresses.

FACTORS RELATED TO TOOTH LOSS AMONG INDUSTRIAL WORKERS IN PHATHUM THANI, THAILAND.

Science.gov (United States)

Jaaidee, Jeerateep; Chatrchaiwiwatana, Supaporn; Ratanasiri, Amornrat

2017-01-01

Tooth loss is an important oral health problem among Thai people. The objectives of this study were to evaluate the prevalence of and factors associated with tooth loss among Thai industrial workers in order to apply preventive oral health programs to this population. The study consisted of 1,500 adults working in Nava Nakorn Industrial Estate, Pathum Thani Province, Thailand in 2014. Probability proportion to size cluster sampling was used and 16 clusters were included in the study. An oral health questionnaire was developed, evaluated for content validity by experts and then given to participants to fill out. The study population consisted of 621 males (41.4%) and 879 females (58.6%) aged between 19-25 years. The overall prevalence of tooth loss was 62.2% and the major reason for tooth loss was dental caries (60%). Results from multivariable logistic regression analysis show that factors associated with tooth loss were: having a history of scaling or tooth cleaning [adjusted odds ratio (AOR)= 2.47; 95% CI: 1.21-4.65], having dental caries with exposed pulp (AOR=4.12; 95% CI: 3.26-7.67), having tooth mobility due to periodontal disease (AOR=2.41; 95% CI: 2.71-5.22), having needed tooth restoration (AOR=1.75; 95% CI: 1.23-2.65), having a history of maxillofacial or a temporo-mandibular joint accident (AOR=2.13; 95% CI: 1.87- 3.23), wearing dentures (AOR=2.58; 95% CI: 2.17-6.72), using dental care services during the previous year (AOR=2.21; 95% CI: 1.26-4.57), eating snacks and candy daily (AOR=2.14; 95% CI: 1.82-2.92), having toothache (AOR=2.64; 95% CI: 1.43- 3.92), having dental caries (AOR=2.23; 95% CI: 1.62-3.27) and having a history of orthodontic treatment (AOR=3.61; 95% CI: 1.84-5.68). The Nagelkerke R squared for the model was 0.42. Our findings suggest several clinical, socio-economic and lifestyle factors are associated with tooth loss among these Thai industrial workers. An appropriate preventive oral health program targeting this high-risk group taking

Reasons for tooth mortality as perceived by dental professionals in ...

African Journals Online (AJOL)

Conclusion: The results of the present study suggest that among the patients attending dental clinics and hospitals in Udaipur city, dental caries and periodontal disease was found to be the two major causes of tooth mortality. This is probably the first study to report on the trends in tooth loss in general practice in Udaipur ...

Prosthetic clone and natural human tooth comparison by speckle interferometry

Science.gov (United States)

Slangen, Pierre; Corn, Stephane; Fages, Michel; Raynal, Jacques; Cuisinier, Frederic J. G.

2010-09-01

New trends in dental prosthodontic interventions tend to preserve the maximum of "body" structure. With the evolution of CAD-CAM techniques, it is now possible to measure "in mouth" the remaining dental tissues. The prosthetic crown is then designed using this shape on which it will be glued on, and also by taking into account the contact surface of the opposite jaw tooth. Several theories discuss on the glue thickness and formulation, but also on the way to evolve to a more biocompatible crown and also new biomechanical concepts. In order to validate these new concepts and materials, and to study the mechanical properties and mechanical integrity of the prosthesis, high resolution optical measurements of the deformations of the glue and the crown are needed. Samples are two intact premolars extracted for orthodontics reasons. The reference sample has no modifications on the tooth while the second sample tooth is shaped to receive a feldspathic ceramic monoblock crown which will be glued. This crown was manufactured with a chairside CAD-CAM system from an intra-oral optical print. The software allows to realize a nearly perfect clone of the reference sample. The necessary space for the glue is also entered with ideal values. This duplication process yields to obtain two samples with identical anatomy for further processing. The glue joint thickness can also be modified if required. The purpose is to compare the behaviour of a natural tooth and its prosthetic clone manufactured with "biomechanical" concepts. Vertical cut samples have been used to deal with planar object observation, and also to look "inside" the tooth. We have developed a complete apparatus enabling the study of the compressive mechanical behaviour of the concerned tooth by speckle interferometry. Because in plane displacements are of great interest for orthodontic measurements1, an optical fiber in-plane sensitive interferometer has been designed. The fibers are wrapped around piezoelectric

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)

Sodium hyaluronate accelerates the healing process in tooth sockets of rats.

Science.gov (United States)

Mendes, Renato M; Silva, Gerluza A B; Lima, Miguel F; Calliari, Marcelo V; Almeida, Alvair P; Alves, José B; Ferreira, Anderson J

2008-12-01

In this study we evaluated the effects of sodium hyaluronate (HY) in the healing process of tooth sockets of rats. Immediately after the extraction of the upper first molars of male Holtzman rats, right sockets were treated with 1% HY gel (approximately 0.1 ml), while left sockets were used as control (blood clot). The animals were sacrificed at 2, 7, and 21 days after tooth extraction and upper maxillaries processed for histological and morphometric analysis of the apical and medium thirds of the sockets. Carbopol, an inert gel, was used to evaluate the mechanical effect of gel injection into sockets. Expression of bone morphogenetic protein-2 (BMP-2) and osteopontin (OPN) was determined by immunohistochemistry at 1, 2, 3, 4, 5, and 7 days after tooth extraction. Histological analysis showed that HY treatment induced earlier trabecular bone deposition resulting in a bone matrix more organized at 7 and 21 days after tooth extraction. Also, HY elicited significant increase in the amount of bone trabeculaes at 7 and 21 days after tooth extraction (percentage of trabecular bone area at 7 days: 13.21+/-4.66% vs. 2.58+/-1.36% in the apical third of control sockets) and in the vessels counting at 7 days. Conversely, the number of cell nuclei was decreased in HY-treated sockets. Additionally, expression of BMP-2 and OPN was enhanced in HY-treated sockets compared with control sockets. These findings suggest that HY accelerates the healing process in tooth sockets of rats stimulating the expression of osteogenic proteins.

Estimation of Tooth Size Discrepancies among Different Malocclusion Groups

OpenAIRE

Hasija, Narender; Bala, Madhu; Goyal, Virender

2014-01-01

ABSTRACT Regards and Tribute: Late Dr Narender Hasija was a mentor and visionary in the light of knowledge and experience. We pay our regards with deepest gratitude to the departed soul to rest in peace. Bolton’s ratios help in estimating overbite, overjet relationships, the effects of contemplated extractions on posterior occlusion, incisor relationships and identification of occlusal misfit produced by tooth size discrepancies. Aim: To determine any difference in tooth size discrepancy in a...

Interactive effects of periodontitis and orthodontic tooth movement on dental root resorption, tooth movement velocity and alveolar bone loss in a rat model.

Science.gov (United States)

Kirschneck, Christian; Fanghänel, Jochen; Wahlmann, Ulrich; Wolf, Michael; Roldán, J Camilo; Proff, Peter

2017-03-01

Many adult orthodontic patients suffer from chronic periodontitis with recurrent episodes of active periodontal inflammation. As their number is steadily increasing, orthodontists are more and more frequently challenged by respective treatment considerations. However, little is currently known regarding interactive effects on undesired dental root resorption (DRR), tooth movement velocity, periodontal bone loss and the underlying cellular and tissue reactions. A total of 63 male Fischer344 rats were used in three consecutive experiments employing 21 animals each (A/B/C), randomly assigned to 3 experimental groups (n=7, 1/2/3), respectively: (A) CBCT; (B) histology/serology; (C) RT-qPCR-(1) control; (2) orthodontic tooth movement (OTM) of the first/second upper left molars (NiTi coil spring, 0.25N); (3) OTM with experimentally induced periodontitis (cervical silk ligature). After 14days of OTM, we quantified blood leukocyte level, DRR, osteoclast activity and relative gene expression of inflammatory and osteoclast marker genes within the dental-periodontal tissue as well as tooth movement velocity and periodontal bone loss after 14 and 28 days. The experimentally induced periodontal bone loss was significantly increased by concurrent orthodontic force application. Periodontal inflammation during OTM on the other hand significantly augmented the extent of DRR, relative expression of inflammatory/osteoclast marker genes, blood leukocyte level and periodontal osteoclast activity. In addition, contrary to previous studies, we observed a significant increase in tooth movement velocity. Although accelerated tooth movement would be favourable for orthodontic treatment, our results suggest that orthodontic interventions should only be performed after successful systematic periodontal therapy and paused in case of recurrent active inflammation. Copyright © 2016 Elsevier GmbH. All rights reserved.

Canine tooth size and fitness in male mandrills (Mandrillus sphinx).

Science.gov (United States)

Leigh, Steven R; Setchell, Joanna M; Charpentier, Marie; Knapp, Leslie A; Wickings, E Jean

2008-07-01

Sexual selection theory explains the evolution of exaggerated male morphologies and weaponry, but the fitness consequences of developmental and age-related changes in these features remain poorly understood. This long-term study of mandrill monkeys (Mandrillus sphinx) demonstrates how age-related changes in canine tooth weaponry and adult canine size correlate closely with male lifetime reproductive success. Combining long-term demographic and morphometric data reveals that male fitness covaries simply and directly with canine ontogeny, adult maximum size, and wear. However, fitness is largely independent of other somatometrics. Male mandrills sire offspring almost exclusively when their canines exceed approximately 30 mm, or two-thirds of average adult value (45 mm). Moreover, sires have larger canines than nonsires. The tooth diminishes through wear as animals age, corresponding with, and perhaps influencing, reproductive senescence. These factors combine to constrain male reproductive opportunities to a brief timespan, defined by the period of maximum canine length. Sexually-selected weaponry, especially when it is nonrenewable like the primate canine tooth, is intimately tied to the male life course. Our analyses of this extremely dimorphic species indicate that sexual selection is closely intertwined with growth, development, and aging, pointing to new directions for sexual selection theory. Moreover, the primate canine tooth has potential as a simple mammalian system for testing genetically-based models of aging. Finally, the tooth may record details of life histories in fossil primates, especially when sexual selection has played a role in the evolution of dimorphism.

Ancient DNA: Saber-Toothed Cats Are the Same Beasts After All.

Science.gov (United States)

Meachen, Julie A

2017-11-06

Ancient DNA from the saber-toothed cat Homotherium reveals that the late Pleistocene species from Europe and North America were the same. Homotherium turns out to be only distantly related to the well-known saber-toothed Smilodon. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Tooth and Skin Colour Interrelationship across the Different Ethnic Groups.

Science.gov (United States)

Haralur, Satheesh B; Dibas, Ahmed Mohammed; Almelhi, Nabil Abdullah; Al-Qahtani, Dhafer Ali

2014-01-01

Objectives. The purpose of the study was to investigate the relation between skin and tooth colour parameters in various ethnic groups. Materials and Methods. Saudi Arabian, Indian, African, and East Asian ethnic groups of 75 each were included in the study. The tooth colour was determined by spectrophotometer in CIELAB parameters. The skin colour was measured at earlobe, forehead, and malar locations by clinical skin photography. The data was statistically analysed by one-way ANOVA and correlation tests. Results. The "L" vale for the Saudi Arabian group had a strong correlation at earlobe location (r = 0.275), while correlation was found at forehead (r = 0.271) and malar region (r = 0.261) with Indian ethnic group. A strong negative correlation was observed in African ethnic group at all three locations for "L" parameter. The redness value "a" is found to have strong negative linear correlation between the earlobe and tooth for Saudi Arabian (r = -0.240) and Indian ethnic groups (r = -0.268). The "b" showed no correlation with skin location in all groups except positive correlation in African ethnic groups. Conclusions. The strong correlation was found between the skin and tooth colour parameters; hence the skin colour can be used as a guide for artificial tooth selection in edentulous patients.

Dosimetric response evaluation of tooth enamel for accelerator-based neutron radiation

International Nuclear Information System (INIS)

Khan, R.F.H.; Rink, W.J.; Boreham, D.R.

2003-01-01

To study the neutron response of human tooth enamel, a number of experiments with an accelerator-based neutron source have been designed. The neutron beam was produced with the low gamma yield, 7 Li(p,n) 7 Be type thick target, using the 3 MV McMaster K.N. Van de Graaff accelerator. The dosimetry was done using a pre-calibrated snoopy type neutron dosimeter. Neutron irradiation induces a dosimetric signal in the tooth enamel at the same defect site as gamma produced damage with the same g-values (g parallel =1.9973, width 0.4 mT g perpendicular =2.002, width 0.3 mT). The dosimetric signal grows linearly with neutron dose from 6-35 Gy tissue dose. Dosimetric response in two different grain sizes (300-500 μm, and grains <4 mm) has shown increased dosimetric amplitude in the larger grains. Dose build up effect on tooth inside the mouth due to cheek was simulated by placing a 4 mm thick paraffin wax layer between the beam and tooth, but had little effect. These results show that for mean neutron energy of 280 keV, the relative neutron response of the human tooth enamel ranges from 8% to 12% of the equivalent gamma ray response

Methodic of the gamma-rays absorbed dose measurements on tooth enamel

International Nuclear Information System (INIS)

Linev, S.V.; Muravskij, V.A.; Mashevskij, A.A.; Ugolev, I.I.

1997-01-01

The analysis of the metrological aspects of the tooth enamel ESR dosimetry has been done. The sample preparation and measurement methods have been elaborated. The methods have passed metrological certification. The methods include tabletting of the mixture of tooth enamel powder and MnO paramagnetic centres concentration additional standard, two loops of additional irradiation of samples by 1 Gy dose and ESR-spectra measurements, calculation of absorbed dose by maximum likelihood algorithm. The algorithm of dose calculation uses enamel spectrum model with axial anisotropic spin-Hamiltonian based on 126 spectra of enamel samples. The algorithm takes into account spectra of the empty cavity, the tube for a sample, the glue and MnO standard. Certificated ESR-station is based on the ESR-analyser PS-100X. ESR-station provides tooth enamel absorbed dose measurements from 0.05 to 0.25 Gy with error 35%, and from 0.25 to 3 Gy with error 20%. The set of tooth enamel absorbed dose standard samples has been created and certificated for the purposes of ESR-station testing and certification. The set consists of 12 tabletted samples of tooth enamel irradiated by doses from 0.05 to 4 Gy. (authors). 7 refs., 1 tab., 2 figs

Retrospective dosimetry assessment using the 380 deg. C thermoluminescence peak of tooth enamel

Energy Technology Data Exchange (ETDEWEB)

Secu, C.E. [National Institute for Materials Physics, PO Box MG-7, 77125 Bucharest-Magurele (Romania); Cherestes, M. [Dozimed Ltd., Dosimetry Laboratory, 77125 Bucharest-Magurele (Romania); Secu, M., E-mail: msecu@infim.ro [National Institute for Materials Physics, PO Box MG-7, 77125 Bucharest-Magurele (Romania); Cherestes, C.; Paraschiva, V. [Dozimed Ltd., Dosimetry Laboratory, 77125 Bucharest-Magurele (Romania); Barca, C. [Faculty of Physics, University of Bucharest, 77125 Bucharest-Magurele (Romania)

2011-10-15

The thermoluminescence (TL) response to gamma-ray irradiation of tooth enamel is reported. The tooth enamel was separated from dentine by using mechanical and physico-chemical procedures followed by grinding (grain size {approx}100 {mu}m) and etching. The TL was attributed to the recombination of CO{sub 2}{sup -} radicals incorporated into or attached to the surface of hydroxyapatite crystals. The growth of the {approx}380 deg. C TL peak with absorbed dose was examined with irradiated tooth enamel samples and reconstructed doses evaluated for tooth enamel samples from four human subjects. - Highlights: > Thermoluminescence response after gamma-ray irradiation of tooth enamel was investigated. > Thermoluminescence was attributed to the recombination of CO{sub 2}{sup -} radicals. > CO{sub 2}{sup -} radicals are produced inside or at the surface of hydroxyapatite crystals. > From the growth of the 380C peak reconstructed doses have been evaluated.

Web-Based, Pictograph-Formatted Discharge Instructions for Low-Literacy Older Adults After Hip Replacement Surgery: Findings of End-User Evaluation of the Website.

Science.gov (United States)

Choi, Jeungok; Jacelon, Cynthia S; Kalmakis, Karen A

The purpose of this study was to develop web-based, pictograph-formatted discharge instructions and evaluate the website with intended users to maximize the relevance and clarity of the website. A descriptive study. Low-literacy text and 45 sets of pictographs were implemented in web-based instructions. The content, design, function, and navigation of the website were reviewed by 15 low-literate older adults following hip replacement surgery. Participants observed that the simple line drawings with clear background were well suited to web pages and helped to convey the points made. They also suggested changes such as adding an additional alphabetical index menu to enhance easy navigation and removing hypertext links to avoid distraction. Web-based, pictograph-formatted discharge instructions were well received by low-literate older adults, who perceived the website easy to use and understand. A pictograph-formatted approach may provide effective strategies to promote understanding of lengthy, complex action-based discharge instructions in rehabilitation facilities.

All-ceramic inlay-retained fixed dental prostheses for replacing posterior missing teeth: A systematic review.

Science.gov (United States)

Castillo-Oyagüe, Raquel; Sancho-Esper, Rocío; Lynch, Christopher D; Suárez-García, María-Jesús

2018-01-01

To evaluate the current status of all-ceramic inlay-retained fixed dental prostheses (CIR-FDPs) for the replacement of posterior teeth. Screening of titles and abstracts, full-text analysis for inclusion eligibility, quality assessment, data extraction and evaluation of the scientific evidence were performed independently by two reviewers. The electronic databases MEDLINE/PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Compludoc were searched with no restriction to publication date or language. The quality of the studies was evaluated through: the original 'QDP' ('Questionnaire for selecting articles on Dental Prostheses') (for research papers); the 'Guidelines for managing overviews' of the Evidence-Based Medicine Working Group (for reviews); the Cochrane risk of bias tool; and the GRADE scale for grading scientific evidence. This review started with 4942 articles, which were narrowed down to 23 according to the selection criteria. The data was not statistically treated because of the heterogeneity of the studies. Zirconia-based CIR-FDPs may be recommended for restoring posterior single missing teeth, although the prosthesis/tooth bonded interface has yet to be improved. The addition of lateral wings to the classical inlay preparation seems promising. The weakest parts of CIR-FDPs are the connectors and retainers, while caries and endodontic problems are the most common biological complications. The fabrication of CIR-FDPs with monolithic zirconia may eliminate chipping problems. A three-unit CIR-FDP is a viable treatment option for replacing a posterior missing tooth. Appropriate case selection, abutment preparation and luting procedures may be decisive for clinical success. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

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.

Abutment tooth loss in patients with overdentures.

Science.gov (United States)

Ettinger, Ronald L; Qian, Fang

2004-06-01

Since the 1960s, the use of natural teeth as overdenture abutments has become part of accepted clinical practice. Several longitudinal studies have been conducted, but tooth loss has not been reported to be a significant problem. The aim of this study was to identify the incidence and causes of tooth loss in a prospective cohort study of subjects wearing overdentures. The study, conducted between 1973 and 1994, evaluated 273 subjects (62.3 percent male) with a mean age of 59.6 years. Of the 273 subjects with 666 abutments, 74 lost 133 abutments. The most common cause of tooth loss was periodontal disease (29.3 percent) followed by periapical lesions (18.8 percent) and caries (16.5 percent). Through logistic regression, the authors found that subjects who lost teeth were more likely to have medical problems that could cause soft-tissue lesions of the oral mucosa, were less likely to use fluoride daily and were less likely to return for yearly recall visits. The authors found 22 vertical fractures in 17 subjects. Chi2 analysis revealed that overdenture teeth in the maxillary arch that were opposed by natural teeth were more likely to experience vertical fractures. In a study that followed up some patients for as long as 22 years, the rate of tooth loss was 20.0 percent. Many of these failures could have been prevented if patients had practiced better oral hygiene. The findings suggest that if a dentist recommends overdenture therapy, the patient needs to be examined regularly to reduce the risk of experiencing caries and periodontal disease. Also, if the abutments are in the maxilla and are opposed by natural teeth, the dentist should consider using thimble crowns to reduce the risk of vertical fractures.

Tooth extraction by orthodontic force after radiation therapy: report of case

Energy Technology Data Exchange (ETDEWEB)

Rodu, B.; Filler, S.J.; Woodfin, G.K.

1985-12-01

This report presents a therapeutic approach to orthodontic tooth extraction in a patient at high risk for the development of osteoradionecrosis with conventional techniques. The rationale for this procedure is discussed in detail, combining principles of radiation biology, clinical radiation therapy, and biomechanics of tooth movement.

Tooth extraction by orthodontic force after radiation therapy: report of case

International Nuclear Information System (INIS)

Rodu, B.; Filler, S.J.; Woodfin, G.K.

1985-01-01

This report presents a therapeutic approach to orthodontic tooth extraction in a patient at high risk for the development of osteoradionecrosis with conventional techniques. The rationale for this procedure is discussed in detail, combining principles of radiation biology, clinical radiation therapy, and biomechanics of tooth movement

Severe tooth wear in Prader-Willi syndrome. A case-control study.

Science.gov (United States)

Saeves, Ronnaug; Espelid, Ivar; Storhaug, Kari; Sandvik, Leiv; Nordgarden, Hilde

2012-05-28

Prader-Willi syndrome (PWS) is a rare complex multsystemic genetic disorder characterized by severe neonatal hypotonia, endocrine disturbances, hyperphagia and obesity, mild mental retardation, learning disabilities, facial dysmorphology and oral abnormalities. The purpose of the present study was to explore the prevalence of tooth wear and possible risk factors in individuals with Prader-Willi syndrome. Forty-nine individuals (6-40 years) with PWS and an age- and sex-matched control group were included. Tooth wear was evaluated from dental casts and intraoral photographs and rated by four examiners using the Visual Erosion Dental Examination (VEDE) scoring system and the individual tooth wear index IA. In accordance with the VEDE scoring system, tooth wear was also evaluated clinically. Whole saliva was collected. Mean VEDE score was 1.70 ± 1.44 in the PWS group and 0.46 ± 0.36 in the control group (p Prader-Willi syndrome. There is therefore considerable need for prosthodontic rehabilitation in young adults with PWS.

The Absolute Deviation Rank Diagnostic Approach to Gear Tooth Composite Fault

Directory of Open Access Journals (Sweden)

Guangbin Wang

2017-01-01

Full Text Available Aiming at nonlinear and nonstationary characteristics of the different degree with single fault gear tooth broken, pitting, and composite fault gear tooth broken-pitting, a method for the diagnosis of absolute deviation of gear faults is presented. The method uses ADAMS, respectively, set-up dynamics model of single fault gear tooth broken, pitting, and composite fault gear tooth broken-pitting, to obtain the result of different degree of broken teeth, pitting the single fault and compound faults in the meshing frequency, and the amplitude frequency doubling through simulating analysis. Through the comparison with the normal state to obtain the sensitive characteristic of the fault, the absolute value deviation diagnostic approach is used to identify the fault and validate it through experiments. The results show that absolute deviation rank diagnostic approach can realize the recognition of gear single faults and compound faults with different degrees and provide quick reference to determine the degree of gear fault.

Expression of Sox genes in tooth development.

Science.gov (United States)

Kawasaki, Katsushige; Kawasaki, Maiko; Watanabe, Momoko; Idrus, Erik; Nagai, Takahiro; Oommen, Shelly; Maeda, Takeyasu; Hagiwara, Nobuko; Que, Jianwen; Sharpe, Paul T; Ohazama, Atsushi

2015-01-01

Members of the Sox gene family play roles in many biological processes including organogenesis. We carried out comparative in situ hybridization analysis of seventeen sox genes (Sox1-14, 17, 18, 21) during murine odontogenesis from the epithelial thickening to the cytodifferentiation stages. Localized expression of five Sox genes (Sox6, 9, 13, 14 and 21) was observed in tooth bud epithelium. Sox13 showed restricted expression in the primary enamel knots. At the early bell stage, three Sox genes (Sox8, 11, 17 and 21) were expressed in pre-ameloblasts, whereas two others (Sox5 and 18) showed expression in odontoblasts. Sox genes thus showed a dynamic spatio-temporal expression during tooth development.

Tooth erosion awareness in a Brazilian dental school.

Science.gov (United States)

Hermont, Ana Paula; Oliveira, Patricia A D; Auad, Sheyla M

2011-12-01

The aim of this cross-sectional study was to assess awareness and attitudes related to tooth erosion among dental students, patients, and faculty members in a Brazilian dental school. Data were collected by means of a self-applied questionnaire that was distributed among 298 participants. The response rate was 89.6 percent. Chi-square and Fisher's exact tests were used for statistical analysis (perosion (72.9 percent), with lower percentages among the patients (perosion (p=0.004). Almost 30 percent of the students did not know if they had had a patient with erosion, and 73.1 percent reported they were not advised by their clinical supervisor to examine their patients for tooth erosion (p=0.138). Concerning the faculty, 23.6 percent of them along with 61.5 percent of the students did not feel prepared to diagnose the condition (perosion (89.6 percent). Knowledge about tooth erosion was not as widely evident as it should be in this sample, suggesting the need for better understanding and communication in this important area of oral health care.

Cigarette smoking and tooth loss experience among young adults: a national record linkage study

Directory of Open Access Journals (Sweden)

Tanaka Keiko

2007-11-01

Full Text Available Abstract Background Various factors affect tooth loss in older age including cigarette smoking; however, evidence regarding the association between smoking and tooth loss during young adulthood is limited. The present study examined the association between cigarette smoking and tooth loss experience among adults aged 20–39 years using linked data from two national databases in Japan. Methods Two databases of the National Nutrition Survey (NNS and the Survey of Dental Diseases (SDD, which were conducted in 1999, were obtained from the Ministry of Health, Labor and Welfare with permission for analytical use. In the NNS, participants received physical examinations and were interviewed regarding dietary intake and health practices including cigarette smoking, whereas in the SDD, participants were asked about their frequency of daily brushing, and received oral examinations by certified dentists. Among 6,805 records electronically linked via household identification code, 1314 records of individuals aged 20 to 39 years were analyzed. The prevalence of 1+ tooth loss was compared among non-, former, and current smokers. Multiple logistic regression models were constructed including confounders: frequency of tooth brushing, body mass index, alcohol consumption, and intake of vitamins C and E. Results Smoking rates differed greatly in men (53.3% and women (15.5%. The overall prevalence of tooth loss was 31.4% (31.8% men and 31.1% women. Tooth loss occurred more frequently among current smokers (40.6% than former (23.1% and non-smokers (27.9%. Current smoking showed a significant association with 1+ tooth loss in men (adjusted OR = 2.21 [1.40–3.50], P = 0.0007 and women (1.70 [1.13–2.55], P = 0.0111. A significant positive exposure-related relationship between cigarette smoking status and tooth loss was observed (P for trend Conclusion An association between cigarette smoking and tooth loss was evident among young adults throughout Japan. Due to

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)

Assessment of the amount of tooth wear on dental casts and intra-oral photographs

NARCIS (Netherlands)

Wetselaar, P.; Wetselaar-Glas, M.J.M.; Koutris, M.; Visscher, C.M.; Lobbezoo, F.

2016-01-01

Tooth wear is a multifactorial condition, leading to the loss of dental hard tissues. Many grading scales are available to assess the amount of tooth wear, one of which is the tooth wear evaluation system (TWES). A grading scale can be used chairside, on casts and on photographs. The aim was to test

Anterior maxillary distraction using a tooth-borne device for hypoplastic cleft maxillas-a pilot study.

Science.gov (United States)

Richardson, Sunil; Agni, Nisheet A; Selvaraj, Dhivakar

2011-12-01

The management of maxillary retrusion in a patient with cleft lip and palate is performed using Le Fort I advancement or distraction osteogenesis using an external or an internal device. Distraction mostly involves movement of the entire maxilla at the Le Fort I level and is characterized by a higher relapse rate and a hampering of speech. Hence, distraction of the anterior maxilla was performed using a tooth-borne palatal distractor similar to the one proposed by Gunaseelan et al (J Oral Maxillofac Surg 65:1044, 2007). However, the technique was modified by placing the distractor preoperatively before performing the osteotomy cut. The main advantage of this modification is that more control over the vector can be achieved and chances of cement failure caused by contamination and an inability to achieve isolation is drastically decreased. This study investigated the efficacy and stability of anterior maxillary distraction in the management of cleft maxillary retrognathia and any resulting complications. Fourteen patients older than 12 years with cleft maxillary retrognathia were included in the study irrespective of gender, type of cleft lip and palate, and the amount of advancement needed. The patients were evaluated using Orthopantomogram and lateral cephalograms preoperatively and at 3 months postoperatively (ie, before appliance removal) and at 6 months postoperatively. The distractor was fabricated extraorally on a cast and cemented into the patient's mouth the day before surgery. The initial deficiency, amount of advancement achieved, and relapses at 6 months, if any, were studied. The data were tabulated and analyzed. Only 1 of the 14 patients showed a relapse, of 2 mm, because this patient was lost to follow-up and thus delayed tooth replacement. Anterior maxillary distraction with a tooth-borne device is a feasible modality for the management of cleft maxillary retrognathia, with stable results. Copyright © 2011 American Association of Oral and

Tooth Wear Inclination in Great Ape Molars.

Science.gov (United States)

Knight-Sadler, Jordan; Fiorenza, Luca

2017-01-01

Primate dietary diversity is reflected in their dental morphology, with differences in size and shape of teeth. In particular, the tooth wear angle can provide insight into a species' ability to break down certain foods. To examine dietary and masticatory information, digitized polygon models of dental casts provide a basis for quantitative analysis of wear associated with tooth attrition. In this study, we analyze and compare the wear patterns of Pongo pygmaeus, Gorilla gorillagorilla and Pan troglodytes schweinfurthii lower molars, focusing on the degree of inclination of specific wear facets. The variation in wear angles appears to be indicative of jaw movements and the specific stresses imposed on food during mastication, reflecting thus the ecology of these species. Orangutans exhibit flatter wear angles, more typical of a diet consisting of hard and brittle foods, while gorillas show a wear pattern with a high degree of inclination, reflecting thus their more leafy diet. Chimpanzees, on the other hand, show intermediate inclinations, a pattern that could be related to their highly variable diet. This method is demonstrated to be a powerful tool for better understanding the relationship between food, mastication and tooth wear processes in living primates, and can be potentially used to reconstruct the diet of fossil species. © 2017 S. Karger AG, Basel.

Transplantation of premolars as an approach for replacing avulsed teeth

DEFF Research Database (Denmark)

Andreasen, Jens Ove; Schwartz, Ole; Kofoed, Thomas

2009-01-01

Autotransplantation of premolars to the anterior region subsequent to tooth loss represent a unique treatment method that has a number of advantages in comparison with other tooth substitution methods. A tooth transplant has a bone inducing capacity implying that lost labial bone is regenerated. ...

The 3rd international intercomparison on EPR tooth dosimetry: Part 1, general analysis

International Nuclear Information System (INIS)

Wieser, A.; Debuyst, R.; Fattibene, P.

2005-01-01

The objective of the 3rd International Intercomparison on Electron Paramagnetic Resonance (EPR) Tooth Dosimetry was the evaluation of laboratories performing tooth enamel dosimetry below 300 mGy. Participants had to reconstruct the absorbed dose in tooth enamel from 11 molars, which were cut into two halves. One half of each tooth was irradiated in a 60 Co beam to doses in the ranges of 30-100 mGy (5 samples), 100-300 mGy (5 samples), and 300-900 mGy (1 sample). Fourteen international laboratories participated in this intercomparison programme. A first analysis of the results and an overview of the essential features of methods applied in different laboratories are presented. The relative standard deviation of results of all methods was better than 27% for applied doses in the range of 79-704 mGy. In the analysis of the unirradiated tooth halves 8% of the samples were identified as outliers with additional absorbed dose above background dose

Permanent tooth loss and sugar-sweetened beverage intake in U.S. young adults.

Science.gov (United States)

Kim, Sunkyung; Park, Sohyun; Lin, Mei

2017-03-01

In young adults, sugar-sweetened beverage (SSB) intake is associated with dental caries, which in turn is a major contributor to tooth loss. The independent role of SSB intake on tooth loss, however, has not been well-described. This cross-sectional study examined associations between tooth loss and SSB intake among U.S. young adults. The outcome was number of permanent teeth lost because of dental caries or periodontal disease (0, 1-5, ≥6 teeth). Data from the 2012 Behavioral Risk Factor Surveillance System were used. The 22,526 adults aged 18-39 years completed the Sugar Drink Module. The exposure variable was daily frequency of SSB intake. We used multinomial logistic regression to examine the adjusted associations between tooth loss and daily SSB consumption (0, >0 to 2 times/day). Approximately, 26% of young adults reported losing at least one permanent tooth. Tooth loss was positively associated with SSB intake frequency; the odds of losing 1-5 teeth were higher among adults drinking SSBs >0-2 times/day (OR = 1.97, 95%CI = 1.51-2.58) than non-SSB consumers. The odds of losing ≥6 teeth were higher among adults drinking SSBs 1-2 times/day (OR = 2.20, 95%CI = 1.15-4.22) and >2 times/day (OR = 2.81, 95%CI = 1.37-5.76) than non-SSB consumers. Frequency of SSB consumption was positively associated with tooth loss among young adults even when the average SSB intake was less than one time per day. This study suggests that efforts to reduce SSB intake among young adults may help to decrease the risk of tooth loss. © 2016 American Association of Public Health Dentistry.

SM50 repeat-polypeptides self-assemble into discrete matrix subunits and promote appositional calcium carbonate crystal growth during sea urchin tooth biomineralization.

Science.gov (United States)

Mao, Yelin; Satchell, Paul G; Luan, Xianghong; Diekwisch, Thomas G H

2016-01-01

The two major proteins involved in vertebrate enamel formation and echinoderm sea urchin tooth biomineralization, amelogenin and SM50, are both characterized by elongated polyproline repeat domains in the center of the macromolecule. To determine the role of polyproline repeat polypeptides in basal deuterostome biomineralization, we have mapped the localization of SM50 as it relates to crystal growth, conducted self-assembly studies of SM50 repeat polypeptides, and examined their effect on calcium carbonate and apatite crystal growth. Electron micrographs of the growth zone of Strongylocentrotus purpuratus sea urchin teeth documented a series of successive events from intravesicular mineral nucleation to mineral deposition at the interface between tooth surface and odontoblast syncytium. Using immunohistochemistry, SM50 was detected within the cytoplasm of cells associated with the developing tooth mineral, at the mineral secreting front, and adjacent to initial mineral deposits, but not in muscles and ligaments. Polypeptides derived from the SM50 polyproline alternating hexa- and hepta-peptide repeat region (SM50P6P7) formed highly discrete, donut-shaped self-assembly patterns. In calcium carbonate crystal growth studies, SM50P6P7 repeat peptides triggered the growth of expansive networks of fused calcium carbonate crystals while in apatite growth studies, SM50P6P7 peptides facilitated the growth of needle-shaped and parallel arranged crystals resembling those found in developing vertebrate enamel. In comparison, SM50P6P7 surpassed the PXX24 polypeptide repeat region derived from the vertebrate enamel protein amelogenin in its ability to promote crystal nucleation and appositional crystal growth. Together, these studies establish the SM50P6P7 polyproline repeat region as a potent regulator in the protein-guided appositional crystal growth that occurs during continuous tooth mineralization and eruption. In addition, our studies highlight the role of species

Rolling-Tooth Core Breakoff and Retention Mechanism

Science.gov (United States)

Badescu, Mircea; Bickler, Donald B.; Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi; Hudson, Nicolas H.

2011-01-01

Sampling cores requires the controlled breakoff of the core at a known location with respect to the drill end. An additional problem is designing a mechanism that can be implemented at a small scale that is robust and versatile enough to be used for a variety of core samples. This design consists of a set of tubes (a drill tube and an inner tube) and a rolling element (rolling tooth). An additional tube can be used as a sample tube. The drill tube and the inner tube have longitudinal holes with the axes offset from the axis of each tube. The two eccentricities are equal. The inner tube fits inside the drill tube, and the sample tube fits inside the inner tube. While drilling, the two tubes are positioned relative to each other such that the sample tube is aligned with the drill tube axis and core. The drill tube includes teeth and flutes for cuttings removal. The inner tube includes, at the base, the rolling element implemented as a wheel on a shaft in an eccentric slot. An additional slot in the inner tube and a pin in the drill tube limit the relative motion of the two tubes. While drilling, the drill assembly rotates relative to the core and forces the rolling tooth to stay hidden in the slot along the inner tube wall. When the drilling depth has been reached, the drill bit assembly is rotated in the opposite direction, and the rolling tooth is engaged and penetrates into the core. Depending on the strength of the created core, the rolling tooth can score, lock the inner tube relative to the core, start the eccentric motion of the inner tube, and break the core. The tooth and the relative position of the two tubes can act as a core catcher or core-retention mechanism as well. The design was made to fit the core and hole parameters produced by an existing bit; the parts were fabricated and a series of demonstration tests were performed. This invention is potentially applicable to sample return and in situ missions to planets such as Mars and Venus, to moons such

Functionalized Surface Geometries Induce: “Bone: Formation by Autoinduction”

Directory of Open Access Journals (Sweden)

Ugo Ripamonti

2018-02-01

Full Text Available The induction of tissue formation, and the allied disciplines of tissue engineering and regenerative medicine, have flooded the twenty-first century tissue biology scenario and morphed into high expectations of a fulfilling regenerative dream of molecularly generated tissues and organs in assembling human tissue factories. The grand conceptualization of deploying soluble molecular signals, first defined by Turing as forms generating substances, or morphogens, stemmed from classic last century studies that hypothesized the presence of morphogens in several mineralized and non-mineralized mammalian matrices. The realization of morphogens within mammalian matrices devised dissociative extractions and chromatographic procedures to isolate, purify, and finally reconstitute the cloned morphogens, found to be members of the transforming growth factor-β (TGF-β supergene family, with insoluble signals or substrata to induce de novo tissue induction and morphogenesis. Can we however construct macroporous bioreactors per se capable of inducing bone formation even without the exogenous applications of the osteogenic soluble molecular signals of the TGF-β supergene family? This review describes original research on coral-derived calcium phosphate-based macroporous constructs showing that the formation of bone is independent of the exogenous application of the osteogenic soluble signals of the TGF-β supergene family. Such signals are the molecular bases of the induction of bone formation. The aim of this review is to primarily describe today's hottest topic of biomaterials' science, i.e., to construct and define osteogenetic biomaterials' surfaces that per se, in its own right, do initiate the induction of bone formation. Biomaterials are often used to reconstruct osseous defects particularly in the craniofacial skeleton. Edentulism did spring titanium implants as tooth replacement strategies. No were else that titanium surfaces require functionalized

Nuclear-chemical methods in a hard tooth tissue abrasion study

International Nuclear Information System (INIS)

Gosman, A.; Spevacek, V.; Konicek, J.; Vopalka, D.; Housova, D.; Dolezalova, L.

1999-01-01

The advanced method consists in implantation-labelling of the thin surface layers of the solid objects, e.g. hard tooth tissue, by atoms of suitable natural or artificial radionuclides. Nuclides from the uranium series were implanted into the surface by using nuclear recoil effect at alpha decay of 226 Ra to 222 Rn, alpha decay of 222 Rn to RaA, alpha decay of RaA to RaB (beta-emitter) and further alpha or beta emitters. With regard to chosen alpha detection and to the half-lives of the radionuclides, there was actually measured the activity of 222 Rn, RaA and RaC' in the thin surface layer. This was followed by the laboratory simulation of the abrasion in the system of 'toothbrush - various suspensions of the tooth-pastes - hard tooth tissue (or material standard - ivory)' in specially designed device - the dentoabrasion meter. The activities of the tissue surface measured before and after abrasion were used for calculations of the relative drop of the surface activity. On this basis the influence of various tooth-pastes containing various abrasive substances was determined. (author)

Tooth labeling in cone-beam CT using deep convolutional neural network for forensic identification

Science.gov (United States)

Miki, Yuma; Muramatsu, Chisako; Hayashi, Tatsuro; Zhou, Xiangrong; Hara, Takeshi; Katsumata, Akitoshi; Fujita, Hiroshi

2017-03-01

In large disasters, dental record plays an important role in forensic identification. However, filing dental charts for corpses is not an easy task for general dentists. Moreover, it is laborious and time-consuming work in cases of large scale disasters. We have been investigating a tooth labeling method on dental cone-beam CT images for the purpose of automatic filing of dental charts. In our method, individual tooth in CT images are detected and classified into seven tooth types using deep convolutional neural network. We employed the fully convolutional network using AlexNet architecture for detecting each tooth and applied our previous method using regular AlexNet for classifying the detected teeth into 7 tooth types. From 52 CT volumes obtained by two imaging systems, five images each were randomly selected as test data, and the remaining 42 cases were used as training data. The result showed the tooth detection accuracy of 77.4% with the average false detection of 5.8 per image. The result indicates the potential utility of the proposed method for automatic recording of dental information.

Resection of the Tooth Apex with Diode Laser

Directory of Open Access Journals (Sweden)

Uzunov Tz.

2014-06-01

Full Text Available An “in vitro” experimental study has been carried out on 70 extracted teeth. A laser resection of the root apex has been carried out with diode laser beam with a wavelength of - 810 ± 10 nm. Sequentially a radiation with increasing power has been applied, as follows: 1,3 W, 2W, 3W, 4W, 5W, 6W, 7W, in electro surgery mode. Successful resection of the tooth apex has been performed at: 3W; 4W; 5W; 6W and 7W power. It was established that when laser resected the tooth apex carbonizes.

Estimating ages of white-tailed deer: Age and sex patterns of error using tooth wear-and-replacement and consistency of cementum annuli

Science.gov (United States)

Samuel, Michael D.; Storm, Daniel J.; Rolley, Robert E.; Beissel, Thomas; Richards, Bryan J.; Van Deelen, Timothy R.

2014-01-01

The age structure of harvested animals provides the basis for many demographic analyses. Ages of harvested white-tailed deer (Odocoileus virginianus) and other ungulates often are estimated by evaluating replacement and wear patterns of teeth, which is subjective and error-prone. Few previous studies however, examined age- and sex-specific error rates. Counting cementum annuli of incisors is an alternative, more accurate method of estimating age, but factors that influence consistency of cementum annuli counts are poorly known. We estimated age of 1,261 adult (≥1.5 yr old) white-tailed deer harvested in Wisconsin and Illinois (USA; 2005–2008) using both wear-and-replacement and cementum annuli. We compared cementum annuli with wear-and-replacement estimates to assess misclassification rates by sex and age. Wear-and-replacement for estimating ages of white-tailed deer resulted in substantial misclassification compared with cementum annuli. Age classes of females were consistently underestimated, while those of males were underestimated for younger age classes but overestimated for older age classes. Misclassification resulted in an impression of a younger age-structure than actually was the case. Additionally, we obtained paired age-estimates from cementum annuli for 295 deer. Consistency of paired cementum annuli age-estimates decreased with age, was lower in females than males, and decreased as age estimates became less certain. Our results indicated that errors in the wear-and-replacement techniques are substantial and could impact demographic analyses that use age-structure information. 

Management of External Invasive Cervical Resorption Tooth with Mineral Trioxide Aggregate: A Case Report

Directory of Open Access Journals (Sweden)

Anuja Ikhar

2013-01-01

Full Text Available Invasive cervical resorption is entirely uncommon entities and the etiology is poorly understood. A 19 year old patient presented with fractured upper left central incisor and sinus tract opening on the distobuccal aspect in cervical region. Radiographic examination shows irregular radiolucency over the coronal one-third and it extended externally towards the external invasive resorption. After sectional obturation, the defect was accessed surgically. The resorption area was chemomechanically debrided using irrigant solution. Fibre post placement using flowable composite resin and Mineral Trioxide Aggregate (MTA was used to fill the resorptive defect, and the coronal access was temporarily sealed. Composite restoration was subsequently replaced with ceramic crown after 4 years. Radiographs at 1 and 4 years showed adequate repair of the resorption and endodontic success. Clinically and radiographically the tooth was asymptomatic, and no periodontal pocket was found after a 4-year followup.

Simple direct composite resin restoration on endodontically treated tooth: A case report

Directory of Open Access Journals (Sweden)

Wahyuni Suci Dwiandhany

2016-06-01

Full Text Available Endodontically treated teeth generally havegreat structure loss so that the resistance to fracture is reduced. Therefore, the post-endodontic restoration design that covers the entire cusp (full cuspal coverage is necessary to increase the resistance of teeth to fracture. The aim of this case report is to present direct onlay restoration technique using composite resin material in non-vital tooth with chronic apical periodontitis. A 74-years-old male patient came to the clinic complaining of discomfort in the lower right posterior tooth related to eating since 1 week ago. Clinical examination revealed a large amalgam restoration on the second lower right molar, the tooth is negative to pulp sensitivity test, and tender to percussion. Radiographically, the tooth showed periapical radiolucency at distal and mesial root. The diagnosis of the tooth was chronic apical periodontitis. The treatment plan is a non-vital root canal treatment with multiple visit. Root canal preparation with rotary files (ProTaper Next, Dentsply, Germany was performed on the first visit and irrigated with NaOCl. On the next visit, during subjective examination, there was no pain complaints and the percussion test was negative so the obturation with a single cone technique can be done. On the final visit, direct onlay restoration using nano-hybrid composite resin material (Polofil NHT, Voco, Germany was performed. In conclusion, after 3 months follow up, the marginal integrity of the restoration remains intact and the tooth were functioned properly.

Reactive correction of a maxillary incisor in single-tooth crossbite following periodontal therapy.

Science.gov (United States)

Huang, Chih-Hao; Brunsvold, Michael A

2005-05-01

The reactive correction of a single tooth anterior crossbite following periodontal therapy is described. This case report provides new information regarding correction of a crossbite relationship and con- firms existing reports of tooth movement following periodontal therapy. A 39-year-old woman in good general health presented with a history of recurrent periodontal abscesses of a maxillary incisor. Probing depths of the abscessed tooth ranged from 5 to 12 mm, and class 1 mobility was noted. Radiographs revealed that the tooth had previously been treated endodontically. The patient's periodontal diagnosis was generalized chronic moderate to severe periodontitis. Treatment considerations were complicated by a single-tooth crossbite relationship of the involved incisor and clinical evidence that the periodontal abscess communicated with an apical infection. Treatment of the abscess consisted of cause-related therapy, bone grafting, and occlusal adjustment. Five months after surgical treatment, an edge-to-edge incisal relationship was observed, the first indicator of tooth movement. Further correction to a normal incisal relationship resulted 1 year after modification of the proximal contact. At this time, there was normal probing depth with only slight recession and mobility. Bone fill was radiographically noted. It appears that some cases of maxillary incisor crossbite that are complicated by periodontal disease may be corrected, without orthodontic appliances, following periodontal treatment.

A Survey of tooth morphology teaching methods employed in the United Kingdom and Ireland.

Science.gov (United States)

Lone, M; McKenna, J P; Cryan, J F; Downer, E J; Toulouse, A

2018-01-15

Tooth morphology is a central component of the dental curriculum and is applicable to all dental specialities. Traditional teaching methods are being supplemented with innovative strategies to tailor teaching and accommodate the learning styles of the recent generation of students. An online survey was compiled and distributed to the staff involved in teaching tooth morphology in the United Kingdom and Ireland to assess the importance of tooth morphology in the dentistry curriculum and the methodologies employed in teaching. The results of the survey show that tooth morphology constitutes a small module in the dental curriculum. It is taught in the first 2 years of the dental curriculum but is applicable in the clinical years and throughout the dental career. Traditional teaching methods, lecture and practical, are being augmented with innovative teaching including e-learning via virtual learning environment, tooth atlas and e-books leading to blended learning. The majority of the schools teach both normal dental anatomy and morphologic variations of dental anatomy and utilise plastic teeth for practical and examination purposes. Learning the 3D aspects of tooth morphology was deemed important by most of the respondents who also agreed that tooth morphology is a difficult topic for the students. Despite being core to the dental curriculum, overall minimal time is dedicated to the delivery of tooth morphology, creating a reliance on the student to learn the material. New forms of delivery including computer-assisted learning tools should help sustain learning and previously acquired knowledge. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effect of Dietary Vitamin C on Orthodontic Tooth Movement in Rats

Directory of Open Access Journals (Sweden)

Amirfarhang Miresmaeili

2015-11-01

Full Text Available Objectives: Bone remodeling occurs during orthodontic treatment; this process enables tooth movement. Many factors can affect bone remodeling at the cellular level, such as nutritional supplements that can affect tooth movement. The present study was designed to evaluate the effect of dietary vitamin C on orthodontic tooth movement in rats. Materials and Methods: This study was carried out on 36 six-week male Wistar rats with a mean weight of 225+32 g, which were randomly allocated to two equal groups. Rats in the case group received 1wt% vitamin C in their daily water. Opening springs were placed on the incisor teeth of both case and control groups. After 17 days, rats were sacrificed; the distance between the mesio-incisal angles of these teeth was measured with a digital caliper. Histological sections were made containing incisor teeth and alveolar bone and stained by hematoxylin-eosin. The number of resorption lacunae was evaluated using light microscopy.Results: Our findings showed that the amount of tooth movement in the vitamin C group was significantly higher than that in the control group (P<0.001. The osteoclast counts were significantly higher in vitamin C group (P=0.036.Conclusion: Oral vitamin C can increase orthodontic tooth movement in rats with more osteoclast lacunae around root in the pressure area. 

Effect of Cervical Lessions on the Tooth FEM Study

OpenAIRE

Gabriela Bereşescu; Ligia Brezeanu; Claudia Şoaita

2010-01-01

The approach used until recently concerning the phenomena of dental abfraction points to the conclusion that the cervical area of the tooth, were this type of lesion usually occur, concentrates the stress resulted from the action of the forces applied on various areas on the crown. Moreover, any lesion in the cervical area facilitates the possibility of its advance into the tooth, ultimately fracturing it. Our paper presents a FEM (finite element method) study on the results of a mechanical a...

Dependencies of the radiation sensitivity of human tooth enamel in EPR dosimetry

International Nuclear Information System (INIS)

Wieser, A.; El-Faramawy, N.; Meckbach, R.

2001-01-01

The EPR dose response of tooth enamel was determined for human molars collected in Egypt. The influence of age, gender and residence of the tooth donors as well as tooth position and sample preparation on EPR sensitivity and its variability over the enamel samples was investigated. The EPR sensitivity and its variability were found to depend only on the sample preparation procedure. The variability in EPR sensitivity of enamel from Egyptian teeth was maximally 10% and the mean sensitivity was in good agreement with that of German teeth

A probability distribution model of tooth pits for evaluating time-varying mesh stiffness of pitting gears

Science.gov (United States)

Lei, Yaguo; Liu, Zongyao; Wang, Delong; Yang, Xiao; Liu, Huan; Lin, Jing

2018-06-01

Tooth damage often causes a reduction in gear mesh stiffness. Thus time-varying mesh stiffness (TVMS) can be treated as an indication of gear health conditions. This study is devoted to investigating the mesh stiffness variations of a pair of external spur gears with tooth pitting, and proposes a new model for describing tooth pitting based on probability distribution. In the model, considering the appearance and development process of tooth pitting, we model the pitting on the surface of spur gear teeth as a series of pits with a uniform distribution in the direction of tooth width and a normal distribution in the direction of tooth height, respectively. In addition, four pitting degrees, from no pitting to severe pitting, are modeled. Finally, influences of tooth pitting on TVMS are analyzed in details and the proposed model is validated by comparing with a finite element model. The comparison results show that the proposed model is effective for the TVMS evaluations of pitting gears.

The timing of tooth eruption and root development of permanent canine and premolars in Korean children

Energy Technology Data Exchange (ETDEWEB)

Cheong, Chang Shin; Jung, Yun Hoa; Cho, Bong Hae [Department of Oral and Maxillofacial Radiology, School of Dentistry, Pusan National University, Pusan (Korea, Republic of)

2010-09-15

The aim of this study was to investigate the timing and sequence of eruption of permanent canine and premolars, and to evaluate tooth calcification stage on emergence in Korean children. The sample was comprised of 1,266 children (male 720, female 546) aged from 7-13 years. Tooth eruption and calcification stages were determined through oral and panoramic radiographic examination, respectively. Probit analysis was used to calculate the timing of tooth eruption and tooth calcification stage from these cross-sectional data. In both males and females, eruption occurred around the time when one third of tooth root or more was formed. The sequence was as follows: first premolar, canine, and second premolar in maxilla, and canine, first premolar and second premolar in mandible. Tooth eruption occurred earlier in girls compared with boys, averaging 0.63 years. Eruption sequence is identical in males and females with a trend for females to erupt earlier than males. Tooth eruption becomes earlier over the past decades in Korean children.

The timing of tooth eruption and root development of permanent canine and premolars in Korean children

International Nuclear Information System (INIS)

Cheong, Chang Shin; Jung, Yun Hoa; Cho, Bong Hae

2010-01-01

The aim of this study was to investigate the timing and sequence of eruption of permanent canine and premolars, and to evaluate tooth calcification stage on emergence in Korean children. The sample was comprised of 1,266 children (male 720, female 546) aged from 7-13 years. Tooth eruption and calcification stages were determined through oral and panoramic radiographic examination, respectively. Probit analysis was used to calculate the timing of tooth eruption and tooth calcification stage from these cross-sectional data. In both males and females, eruption occurred around the time when one third of tooth root or more was formed. The sequence was as follows: first premolar, canine, and second premolar in maxilla, and canine, first premolar and second premolar in mandible. Tooth eruption occurred earlier in girls compared with boys, averaging 0.63 years. Eruption sequence is identical in males and females with a trend for females to erupt earlier than males. Tooth eruption becomes earlier over the past decades in Korean children.

Calcium dynamics in the healing of tooth extraction sockets in mice evaluated using 45Ca-autoradiography and Electron Probe Micro Analysis

International Nuclear Information System (INIS)

Tanaka, Takeo

2006-01-01

The calcium distribution in tooth extraction sockets of mice was examined using 45-Calcium autoradiography (ARG) and Electron Probe Micro Analysis (EPMA). Mice were divided into 8 groups (n=8) according to the number of days (1, 2, 3, 4, 5, 7, 10, 20 respectively) after extraction. Frozen sections were taken from mice on each experimental day after injection of 45-Calcium (RI). The process of formation of new bone was observed using ARG. An ultimate analysis was performed by EPMA. Histological analysis was performed with toluidine blue- and alizarin red S-staining. In toluidine blue-staining, an osteoblast was found along the socket wall at 4 days and non-calcified periodontal ligament was recognized until 5 days after extraction. In alizarin red S-staining, new bone was recognized separated from the socket wall at 4 days after extraction. 45 Ca-labeling was detected strongly in the periosteum of the mandible, the surface of cement and periodontal ligament in control animals. 45 Ca-labeling was moved from the bottom to the top of the tooth extraction socket during the period from 1 to 5 days after extraction, but in the periodontal ligament lower than in the granulation tissue. 45 Ca-labeling was detected in the socket at 7, 10 and 20 days. At 4 days, calcium phosphate was observed in the central portion of the socket using EPMA. 45 Ca-labeling showed deposition of calcium phosphate for alveolar bone and new bone. These results suggest that the granulation tissue may be involved in the initial calcification in the tooth extraction socket and lead to the formation of new bone in it. (author)

Computerized Analysis of Digital Photographs for Evaluation of Tooth Movement.

Science.gov (United States)

Toodehzaeim, Mohammad Hossein; Karandish, Maryam; Karandish, Mohammad Nabi

2015-03-01

Various methods have been introduced for evaluation of tooth movement in orthodontics. The challenge is to adopt the most accurate and most beneficial method for patients. This study was designed to introduce analysis of digital photographs with AutoCAD software as a method to evaluate tooth movement and assess the reliability of this method. Eighteen patients were evaluated in this study. Three intraoral digital images from the buccal view were captured from each patient in half an hour interval. All the photos were sent to AutoCAD software 2011, calibrated and the distance between canine and molar hooks were measured. The data was analyzed using intraclass correlation coefficient. Photographs were found to have high reliability coefficient (P > 0.05). The introduced method is an accurate, efficient and reliable method for evaluation of tooth movement.

Evaluation of a Multiple-Stimulus Presentation Format for Assessing Reinforcer Preferences.

Science.gov (United States)

DeLeon, Iser G.; Iwata, Brian A.

1996-01-01

A study of seven adults with profound developmental disabilities compared methods for presenting stimuli during reinforcer-preference assessments. It found that a multiple-stimulus format in which selections were made without replacement may share the advantages of a paired-stimulus format and a multiple-stimulus format with replacement, while…

Oral Health Problems And Causes Of Tooth Loss At The University ...

African Journals Online (AJOL)

Context Several oral diseases and conditions are associated with tooth loss. Objective: The aim of this study was to determine the prevalence of oral health problems seen at the University of Nigeria Teaching Hospital (UNTH) in one year with the view to highlighting causes of tooth loss in this environment. Methods This ...

Causes of Charcot-Marie-Tooth Disease (CMT)

Science.gov (United States)

... Marie-Tooth Disease (CMT) Congenital Muscular Dystrophy (CMD) Duchenne Muscular Dystrophy (DMD) Emery-Dreifuss Muscular Dystrophy Endocrine Myopathies Metabolic Diseases of Muscle Mitochondrial Myopathies (MM) Myotonic Dystrophy (DM) Spinal-Bulbar ...

New method of control of tooth whitening

Science.gov (United States)

Angelov, I.; Mantareva, V.; Gisbrecht, A.; Valkanov, S.; Uzunov, Tz.

2010-10-01

New methods of control of tooth bleaching stages through simultaneous measurements of a reflected light and a fluorescence signal are proposed. It is shown that the bleaching process leads to significant changes in the intensity of a scattered signal and also in the shape and intensity of the fluorescence spectra. Experimental data illustrate that the bleaching process causes essential changes in the teeth discoloration in short time as 8-10 min from the beginning of the application procedure. The continuation of the treatment is not necessary moreover the probability of the enamel destroy increases considerably. The proposed optical back control of tooth surface is a base for development of a practical set up to control the duration of the bleaching procedure.

Initiation and patterning of the snake dentition are dependent on Sonic hedgehog signaling.

Science.gov (United States)

Buchtová, Marcela; Handrigan, Gregory R; Tucker, Abigail S; Lozanoff, Scott; Town, Liam; Fu, Katherine; Diewert, Virginia M; Wicking, Carol; Richman, Joy M

2008-07-01

Here we take the first look at cellular dynamics and molecular signaling in the developing snake dentition. We found that tooth formation differs from rodents in several respects. The majority of snake teeth bud off of a deep, ribbon-like dental lamina rather than as separate tooth germs. Prior to and after dental lamina ingrowth, we observe asymmetries in cell proliferation and extracellular matrix distribution suggesting that localized signaling by a secreted protein is involved. We cloned Sonic hedgehog from the African rock python Python sebae and traced its expression in the species as well as in two other snakes, the closely-related Python regius and the more derived corn snake Elaphe guttata (Colubridae). We found that expression of Shh is first confined to the odontogenic band and defines the position of the future dental lamina. Shh transcripts in pythons are progressively restricted to the oral epithelium on one side of the dental lamina and remain in this position throughout the prehatching period. Shh is expressed in the inner enamel epithelium and the stellate reticulum of the tooth anlagen, but is absent from the outer enamel epithelium and its derivative, the successional lamina. This suggests that signals other than Shh are responsible for replacement tooth formation. Functional studies using cyclopamine to block Hh signaling during odontogenesis prevented initiation and extension of the dental lamina into the mesenchyme, and also affected the directionality of this process. Further, blocking Hh signaling led to disruptions of the inner enamel epithelium. To explore the role of Shh in lamina extension, we looked at its expression in the premaxillary teeth, which form closer to the oral surface than elsewhere in the mouth. Oral ectodermal Shh expression in premaxillary teeth is lost soon after the teeth form reinforcing the idea that Shh is controlling the depth of the dental lamina. In summary, we have found diverse roles for Shh in patterning the

Placement of replace select Ti-Unite-coated type implants using a combination of immediate and submerge techniques after tooth extraction

Directory of Open Access Journals (Sweden)

Coen Pramono D

2006-06-01

Full Text Available The high success rate of immediate implant placement both in the anterior and posterior regions were reported by many authors, therefore applying this techniques can be considered as a safe surgical procedure and minimizing the dental office visit for patient satisfaction. This paper reports the outcome of immediate placement of implants following extraction of anterior maxillary teeth. Combination technique of immediate and submerge implant placements including bone grafting procedure were used. Four implants with TiUnite surface type were placed immediately in two patients with the short-term result indicated that this technique may serve as a simple and safe procedure for immediate implant placement. It was concluded that immediate implant placement technique combined with TiUnite implant surface was successful in treating region directly after tooth extraction therefore this technique can be use as an alternative surgical method for dental implant rehabilitation.

Tooth bleaching using peroxide-containing agents: current status of safety issues.

Science.gov (United States)

Li, Y

1998-08-01

During the last 10 years, at-home tooth bleaching using peroxide-containing agents has quickly become well accepted. It is one of the most popular cosmetic dental procedures for whitening teeth. Although there are few disputes regarding their efficacy, concerns and debates have continued regarding the safety of peroxide-containing tooth bleaching agents. Potential carcinogenicity and genotoxicity of the peroxides used in bleaching agents are the two most persistent and controversial issues. This article reviews and discusses available information on carcinogenicity and genotoxicity of hydrogen peroxide and the potential risks associated with the use of peroxide-containing bleaching agents. Clinical studies reported after the 1996 international symposium on responses of oral tissues to peroxide-containing bleaching agents are also reviewed. Overall evidence supports the conclusion that the proper use of peroxide-containing at-home tooth bleaching agents is safe. However, potential adverse effects may occur in inappropriate applications, abuses, or the use of inappropriate products. At-home tooth bleaching should be monitored by dental professionals to maximize the benefits while minimizing potential risks.

Early detection of tooth wear by en-face optical coherence tomography

Science.gov (United States)

Mărcăuteanu, Corina; Negrutiu, Meda; Sinescu, Cosmin; Demjan, Eniko; Hughes, Mike; Bradu, Adrian; Dobre, George; Podoleanu, Adrian G.

2009-02-01

Excessive dental wear (pathological attrition and/or abfractions) is a frequent complication in bruxing patients. The parafunction causes heavy occlusal loads. The aim of this study is the early detection and monitoring of occlusal overload in bruxing patients. En-face optical coherence tomography was used for investigating and imaging of several extracted tooth, with a normal morphology, derived from patients with active bruxism and from subjects without parafunction. We found a characteristic pattern of enamel cracks in patients with first degree bruxism and with a normal tooth morphology. We conclude that the en-face optical coherence tomography is a promising non-invasive alternative technique for the early detection of occlusal overload, before it becomes clinically evident as tooth wear.

Trends in Social Inequality in Tooth Brushing among Adolescents: 1991-2014

DEFF Research Database (Denmark)

Holstein, Bjørn Evald; Bast, Lotus Sofie; Brixval, Carina Sjöberg

2015-01-01

This study examines whether social inequality in tooth brushing frequency among adolescents changed from 1991 to 2014. The data material was seven comparable cross-sectional studies of nationally representative samples of 11- to 15-year-olds in Denmark with data about frequency of tooth brushing...... and occupation of parents. The total number of participants was 31,464, of whom 21.7% brushed their teeth less than the recommended 2 times a day. The absolute social inequality measured as prevalence difference between low and high social class increased from 7.7% in 1991 to 14.6% in 2014. The relative social...... inequality assessed by odds ratios for infrequent tooth brushing also increased from 1991 to 2014....

Cumulative costs for the prosthetic reconstructions and maintenance in young adult patients with birth defects affecting the formation of teeth.

Science.gov (United States)

Incici, Erol; Matuliene, Giedre; Hüsler, Jürg; Salvi, Giovanni E; Pjetursson, Bjarni; Brägger, Urs

2009-07-01

To assess retrospectively the cumulative costs for the long-term oral rehabilitation of patients with birth defects affecting the development of teeth. Patients with birth defects who had received fixed reconstructions on teeth and/or implants > or =5 years ago were asked to participate in a comprehensive clinical, radiographic and economic evaluation. From the 45 patients included, 18 were cases with a cleft lip and palate, five had amelogenesis/dentinogenesis imperfecta and 22 were cases with hypodontia/oligodontia. The initial costs for the first oral rehabilitation (before the age of 20) had been covered by the Swiss Insurance for Disability. The costs for the initial rehabilitation of the 45 cases amounted to 407,584 CHF (39% for laboratory fees). Linear regression analyses for the initial treatment costs per replaced tooth revealed the formula 731 CHF+(811 CHF x units) on teeth and 3369 CHF+(1183 CHF x units) for reconstructions on implants (Phealthy teeth, fewer tooth units need to be replaced and the cumulative long-term costs seem to be similar compared with cases restored on teeth.

The Role of Mechanical Force in Molecular and Cellular during Orthodontic Tooth Movement

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Ida Bagus Narmada

2012-10-01

Full Text Available Application of mechanical force on abnormally positioned tooth, cause changes in tooth location and transmitted to the bone ia the periodontal ligament (PDL produce orthodontic tooth movement. This force application is further way that remodeling in the area occurs. In order to develop biological strategies for enhancing this movement of teeth in bone, the underlying mechanisms of bone resorption and apposition should be understood in detail. Analysis of gingival crevicular fluid (GCF may be a good means of examining the on going molecular and cellular process associated with gingival and bone turnover during orthodontic tooth movement. If it could be possible to biologically monitor and predict the outcome of orthodontic force, then the appliance management could be based on dividual tissue response and the effectiveness of the treatment could be improved and understanding their biology is critical to finding ways to modify bone biology to move teeth faster. The present article reviewed a short introduction to some mayors advanced mechanical force in molecular and cellular biology during orthodontic tooth movement.DOI: 10.14693/jdi.v15i3.30

Bleaching of the discolored traumatized tooth

DEFF Research Database (Denmark)

Dahl, Jon E.; Kopperud, Siemen E.; Pallesen, Ulla

2018-01-01

This chapter focuses on the treatment of discolored traumatized teeth, most of them being non-vital and subsequently, endodontically treated. Tooth bleaching based upon hydrogen peroxide as the active agent, applied directly or produced in a chemical reaction from sodium perborate or carbamide pe...

Age effect on orthodontic tooth movement

NARCIS (Netherlands)

Ren, Yijin

2003-01-01

This study was performed to investigate the effect of age on the efficiency of orthodontic tooth movement based on critical literature reviews, studies on a standardized orthodontic animal model and a non-invasive clinical investigation. A systematic review was performed on the optimum force for

Storing tooth segments for optimal esthetics

NARCIS (Netherlands)

Tuzuner, T.; Turgut, S.; Özen, B.; Kılınç, H.; Bagis, B.

2016-01-01

Objective: A fractured whole crown segment can be reattached to its remnant; crowns from extracted teeth may be used as pontics in splinting techniques. We aimed to evaluate the effect of different storage solutions on tooth segment optical properties after different durations. Study design: Sixty

MSX1 gene variant - its presence in tooth absence - a case control genetic study.

Science.gov (United States)

Reddy, Naveen Admala; Adusumilli, Gopinath; Devanna, Raghu; Pichai, Saravanan; Rohra, Mayur Gobindram; Arjunan, Sharmila

2013-10-01

Non Syndromic tooth agenesis is a congenital anomaly with significant medical, psychological and social ramifications. There is sufficient evidence to hypothesize that locus for this condition can be identified by candidate genes. The aim of this study was to test whether MSX1 671 T>C gene variant was involved in etiology of Non Syndromic tooth agenesis in Raichur Patients. Blood samples were collected with informed consent from 50 subjects having Non Syndromic tooth agenesis and 50 controls. Genomic DNA was extracted from the blood samples, Polymerase Chain Reaction was performed (PCR) and Restriction Fragment Length Polymorphism (RFLP) was performed for digestion products that were evaluated. The RESULTS showed positive correlation between MSX1671 T>C gene variant and Non Syndromic tooth agenesis in Raichur Patients. MSX1 671 T>C gene variant may be a good screening marker for Non Syndromic tooth agenesis in Raichur Patients . How to cite this article:Reddy NA, Adusumilli G, Devanna R, Pichai S, Rohra MG, Arjunan S. Msx1 Gene Variant - Its Presence in Tooth Absence - A Case Control Genetic Study. J Int Oral Health 2013; 5(5):20-6.

Cellular and molecular basis of tooth eruption

Science.gov (United States)

Wise, GE

2009-01-01

Objectives Tooth eruption requires the presence of a dental follicle (DF), alveolar bone resorption for an eruption pathway, and alveolar bone formation at the base of the bony crypt. The objectives of our investigations have been to determine how the DF regulates both the osteoclastogenesis and osteogenesis needed for eruption. Material & Methods Multiple experimental methods have been employed. Results The DF regulates osteoclastogenesis and osteogenesis by regulating the expression of critical genes in both a chronological and spatial fashion. In the rat 1st mandibular molar there is a major burst of osteoclastogenesis at day 3 postnatally and a minor burst at day 10. At day 3, the DF maximally expresses colony-stimulating factor-1 (CSF-1) to down-regulate the expression of osteoprotegerin such that osteoclastogenesis can occur. At day 10, the minor burst of osteoclastogenesis is promoted by upregulation of VEGF and RANKL in the DF. Spatially, the bone resorption is in the coronal portion of the bony crypt and genes such as RANKL are expressed more in the coronal region of the DF than in its basal one-half. For osteogenesis, bone formation begins at day 3 at the base of the bony crypt and maximal growth is at days 9–14. Osteo-inductive genes such as BMP-2 appear to promote this and are expressed more in the basal half of the DF than in the coronal. Conclusion The osteoclastogenesis and osteogenesis needed for eruption are regulated by differential gene expression in the DF both chronologically and spatially. PMID:19419449

Uneven distribution of enamel in the tooth crown of a Plains Zebra (Equus quagga

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Daniela E. Winkler

2015-06-01

Full Text Available Unworn teeth of herbivorous mammals are not immediately functional. They have to be partially worn to expose enamel ridges which can then act as shear-cutting blades to break the food down. We use the Plains Zebra (Equus quagga as a hypsodont, herbivorous model organism to investigate how initial wear of the tooth crown is controlled by underlying structures. We find that the enamel proportion is smaller at the apical half of the tooth crown in all upper tooth positions and suggest that lower enamel content here could promote early wear. Besides this uneven enamel distribution, we note that the third molar has a higher overall enamel content than any other tooth position. The M3 is thus likely to have a slightly different functional trait in mastication, resisting highest bite forces along the tooth row and maintaining functionality when anterior teeth are already worn down.

Uneven distribution of enamel in the tooth crown of a Plains Zebra (Equus quagga).

Science.gov (United States)

Winkler, Daniela E; Kaiser, Thomas M

2015-01-01

Unworn teeth of herbivorous mammals are not immediately functional. They have to be partially worn to expose enamel ridges which can then act as shear-cutting blades to break the food down. We use the Plains Zebra (Equus quagga) as a hypsodont, herbivorous model organism to investigate how initial wear of the tooth crown is controlled by underlying structures. We find that the enamel proportion is smaller at the apical half of the tooth crown in all upper tooth positions and suggest that lower enamel content here could promote early wear. Besides this uneven enamel distribution, we note that the third molar has a higher overall enamel content than any other tooth position. The M3 is thus likely to have a slightly different functional trait in mastication, resisting highest bite forces along the tooth row and maintaining functionality when anterior teeth are already worn down.

Lip and tooth injuries at public swimming pools in Austria.

Science.gov (United States)

Lechner, Katharina; Connert, Thomas; Kühl, Sebastian; Filippi, Andreas

2017-06-01

There is an increased risk of orofacial injuries in swimming pool facilities. Nevertheless, only a few studies have addressed this issue. The aim of this study was to identify the frequency of lip and tooth injuries at public swimming pools in Austria. A further aim was to examine which gender and age groups were affected, where and why these injuries occurred, and whether pool attendants had sufficient knowledge of dental first-aid measures. A total of 764 pool attendants in Austria were contacted by telephone and 689 participated in the study (90.2%). The attendants were interviewed retrospectively about accident occurrences in 2014 by a standardized questionnaire. Responses to the provision of first aid and choice of storage medium for avulsed teeth were subsequently evaluated. The frequency of lip injuries was 19.0%, and tooth injuries were 11.3%. Male bathers (P < .05) and children under 12 years (P < .001) most frequently suffered injuries. The waterslide was the most common accident site. The most common cause of lip injuries was slipping on wet surfaces (39.0%), and for tooth injuries it was collisions with other persons or objects (each 28.1%). The pool attendants' responses were predominantly good or sufficient on first aid, with the exception of what storage medium to choose. Tooth rescue boxes were available in only 8.6% of all pool facilities. Orofacial injuries are a frequently occurring problem in swimming pool facilities. The pool attendants' knowledge on first-aid care of tooth injuries could still be improved. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Is the relative increase in income inequality related to tooth loss in middle-aged adults?

Science.gov (United States)

Goulart, Mariél de Aquino; Vettore, Mario Vianna

2016-01-01

To assess whether Brazilian middle-aged adults living in cities that experienced a relative increase on income inequality were more likely to have severe tooth loss and lack a functional dentition. Data on Brazilian adults aged 35-44 years from state capitals and Federal District from the 2010 Brazilian Oral Health Survey (SBBrasil 2010) were analyzed. Clinically assessed tooth loss outcomes were severe tooth loss (Income inequality was assessed by Gini Index in 1991, 2000, and 2003 using tertiles of distribution. Variation in Gini Index was assessed by changes in the tertiles distribution between years. Multilevel logistic regression models were used to estimate odds ratios (ORs) and 95 percent confidence intervals (95 percent CI) between variation in income inequality and tooth loss outcomes adjusting for individual socio-demographic characteristics. Prevalence of severe tooth loss and lack of functional dentition was 4.8 percent and 21.2 percent, respectively. Individuals living in cities with moderate and high increase in income inequality between 1991 and 2003 were more likely to have severe tooth loss and lack a functional dentition in 2010 compared with those living in cities with stable income inequality in the same period. Relationships between low family income and both tooth loss outcomes were significantly attenuated by relative increases in income inequality. Relative increases in income inequality were significantly associated with severe tooth loss and lack of a functional dentition in Brazilian middle-aged adults. © 2015 American Association of Public Health Dentistry.

Tooth loss strongly associates with malnutrition in chronic kidney disease.

Science.gov (United States)

Ioannidou, E; Swede, H; Fares, G; Himmelfarb, J

2014-07-01

In chronic kidney disease (CKD), inadequate nutritional intake, inflammation, and increased oxidative stress have been the major contributing factors in malnutrition pathogenesis. However, there is still a paucity of evidence assessing the magnitude of the effect of tooth loss on malnutrition in CKD populations. The authors hypothesize that among patients with CKD, tooth loss may affect nutritional status, using the National Health and Nutrition Examination Survey 1988 to 1994 (NHANES III). Glomerular filtration rate (GFR) was estimated based on cystatin C levels using the relevant equation. Urinary albumin-to-creatinine ratio (albuminuria) was calculated in milligrams per gram with a cutoff point of 30 mg/g. CKD was defined based on estimated GFR protein and caloric intake (P = 0.02 and 0.01, respectively). Serum albumin reached a frequency peak in the fully edentulous group without dentures (group 4, 19.2%). In the same group, individuals had lower protein (30.1%) and caloric intake (30.2%) (P = 0.01 and 0.02, respectively). Furthermore, logistic regression analysis confirmed the significant role of tooth loss on serum albumin and protein and energy intake in this population even after adjusting for confounding variables. Tooth loss independently predicts low energy and protein intake, as well as serum albumin levels, biomarkers of malnutrition in CKD.

Charcot-Marie-Tooth disease.

LENUS (Irish Health Repository)

Reilly, Mary M

2011-03-01

Charcot-Marie-Tooth (CMT) disease is the commonest inherited neuromuscular disorder affecting at least 1 in 2,500. Over the last two decades, there have been rapid advances in understanding the molecular basis for many forms of CMT with more than 30 causative genes now described. This has made obtaining an accurate genetic diagnosis possible but at times challenging for clinicians. This review aims to provide a simple, pragmatic approach to diagnosing CMT from a clinician\\'s perspective.

A systematic review of the consequences of premature birth on palatal morphology, dental occlusion, tooth-crown dimensions, and tooth maturity and eruption.

Science.gov (United States)

Paulsson, Liselotte; Bondemark, Lars; Söderfeldt, Björn

2004-04-01

This systematic review addresses the question whether prematurity results in alteration of palatal morphology, dental occlusion, tooth-crown dimensions, and tooth maturation. A literature survey from the PubMed database covering the period from January 1966 to November 2002 used the Medical Subject Headings terms "infant, premature," and "infant, low birth weight" in combination with "jaws," "dental physiology," "dentition," and "tooth abnormalities." Controlled studies written in English and with definitions of premature birth according to the World Health Organization were selected. Two reviewers selected and extracted the data independently and also assessed the quality of the studies. The search strategy resulted in 113 articles, of which 13 met the inclusion criteria. Scientific evidence was found for altered palatal morphology in the short term among the premature children, and oral intubation was a contributing factor to the alterations. If corrected age was considered for the premature children, no delay in dental development and eruption was found compared with normally born children. Thus, the early birth of premature children must be taken in account when planning for orthodontic treatment. Because of the contradictory results and lack of longitudinal studies, the scientific evidence was too weak to answer the questions whether premature birth causes permanent alteration of palatal morphology, alteration of dental occlusion, and altered tooth-crown dimensions. To answer these questions and obtain reliable scientific evidence whether premature children are at risk for malocclusions from possible alterations of palatal morphology such as asymmetry and high arched palates, further well-designed controlled studies as well as longitudinal studies are needed.

Causes and pattern of tooth loss in children and adolescents in a ...

African Journals Online (AJOL)

Information obtained included age, gender, missing and extracted teeth, and reasons for extraction/tooth loss. Exfoliated primary teeth and congenitally missing teeth were excluded. Data was analysed using Epi info 2007 statistical software. Chi-square test was used to compare proportions of tooth loss among age groups.

Three-dimensional analysis of tooth dimensions in the MSX1-missense mutation

NARCIS (Netherlands)

Creton, M.; Boogaard, M.J. van den; Maal, T.J.; Verhamme, L.M.; Fennis, W.M.M.; Carels, C.E.L.; Kuijpers-Jagtman, A.M.; Cune, M.

2013-01-01

OBJECTIVES: A novel, 3D technique to measure the differences in tooth crown morphology between the MSX1 cases and non-affected controls was designed to get a better understanding of dental phenotype-genotype associations. MATERIALS AND METHODS: Eight Dutch subjects from a single family with tooth

TOOTH COLOR AND REFLECTANCE AS RELATED TO LIGHT-SCATTERING AND ENAMEL HARDNESS

NARCIS (Netherlands)

TENBOSCH, JJ; COOPS, JC

Tooth color is determined by the paths of light inside the tooth and absorption along these paths. This paper tests the hypothesis that, since the paths are determined by scattering, a relation between color and scattering coefficients exists. One hundred and two extracted incisors were fixed in

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.

Gear Fault Detection Effectiveness as Applied to Tooth Surface Pitting Fatigue Damage

Science.gov (United States)

Lewicki, David G.; Dempsey, Paula J.; Heath, Gregory F.; Shanthakumaran, Perumal

2010-01-01

A study was performed to evaluate fault detection effectiveness as applied to gear-tooth-pitting-fatigue damage. Vibration and oil-debris monitoring (ODM) data were gathered from 24 sets of spur pinion and face gears run during a previous endurance evaluation study. Three common condition indicators (RMS, FM4, and NA4 [Ed. 's note: See Appendix A-Definitions D were deduced from the time-averaged vibration data and used with the ODM to evaluate their performance for gear fault detection. The NA4 parameter showed to be a very good condition indicator for the detection of gear tooth surface pitting failures. The FM4 and RMS parameters perfomu:d average to below average in detection of gear tooth surface pitting failures. The ODM sensor was successful in detecting a significant 8lDOunt of debris from all the gear tooth pitting fatigue failures. Excluding outliers, the average cumulative mass at the end of a test was 40 mg.

Epi-detected quadruple-modal nonlinear optical microscopy for label-free imaging of the tooth

Energy Technology Data Exchange (ETDEWEB)

Wang, Zi; Zheng, Wei; Huang, Zhiwei, E-mail: biehzw@nus.edu.sg [Optical Bioimaging Laboratory, Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore 117576 (Singapore); Stephen Hsu, Chin-Ying [Department of Dentistry, Faculty of Dentistry, National University of Singapore and National University Health System, Singapore 119083 (Singapore)

2015-01-19

We present an epi-detected quadruple-modal nonlinear optical microscopic imaging technique (i.e., coherent anti-Stokes Raman scattering (CARS), second-harmonic generation (SHG), third-harmonic generation (THG), and two-photon excited fluorescence (TPEF)) based on a picosecond (ps) laser-pumped optical parametric oscillator system for label-free imaging of the tooth. We demonstrate that high contrast ps-CARS images covering both the fingerprint (500–1800 cm{sup −1}) and high-wavenumber (2500–3800 cm{sup −1}) regions can be acquired to uncover the distributions of mineral and organic biomaterials in the tooth, while high quality TPEF, SHG, and THG images of the tooth can also be acquired under ps laser excitation without damaging the samples. The quadruple-modal nonlinear microscopic images (CARS/SHG/THG/TPEF) acquired provide better understanding of morphological structures and biochemical/biomolecular distributions in the dentin, enamel, and the dentin-enamel junction of the tooth without labeling, facilitating optical diagnosis and characterization of the tooth in dentistry.

Influence of medication on the rate of orthodontic tooth movement (Part 1: hormons and corticosteroids

Directory of Open Access Journals (Sweden)

Mirhashemi Amirhossein

2015-05-01

Full Text Available The aim of this review article was to define the mechanism of action and effects of commonly used medications on the tissue remodeling and Orthodontic Tooth Movement (OTM. A review on the effects of medications and dietary supplements on the rate of experimental tooth movement was performed using Cochrane library, Embase and medline (1980-2013. 63 articles were included in this review. 34 of them were related to the effects of hormones and analgesics, were evaluated in this article but their interpretation was hindered by the variability in experimental design, magnitude of force applied during tooth movement and medication regimens. Non Steroidal Anti-Inflammatory Drugs (NSAIDs reduced the rate of tooth movement while non-NSAIDs such as acetaminophen had no effect on the rate of OTM. Corticosteroids, parathyroid hormone and thyroxin increased the rate of tooth movement. Sturgeons might slow OTM, but experimental studies are lacking. Medications might have an important influence on the rate of tooth movement and information on their consumption is necessary to adequately discuss treatment planning with patients.

Autotransplantation of Mandibular Third Molar: A Case Report

Directory of Open Access Journals (Sweden)

Pabbati Ravi kumar

2012-01-01

Full Text Available Autogenous transplantation is a feasible, fast, and economical option for the treatment of nonsalvageable teeth when a suitable donor tooth is available. This paper presents successful autotransplantation of a mature mandibular left third molar (38 without anatomical variances is used to replace a mandibular left second molar (37. The mandibular second molar was nonrestorable due to extensive root caries and resorption of distal root. After extraction of mandibular second and third molars, root canal therapy was done for the third molar extraorally, and the tooth was reimplanted into the extracted socket of second molar site. After one year, clinical and radiographic examination revealed satisfactory outcome with no signs or symptoms suggestive of pathology. In selected cases, autogenous tooth transplantation, even after complete root formation of the donor tooth, may be considered as a practical treatment alternative to conventional prosthetic rehabilitation or implant treatment.

Tooth-borne distraction of the lower anterior subapical segment for correction of class II malocclusion, subsequent to genioplasty.

Science.gov (United States)

Matsushita, Kazuhiro; Inoue, Nobuo; Yamaguchi, Hiro-o; Ooi, Kazuhiro; Totsuka, Yasunori

2011-09-01

Alveolar distraction is mainly used to increase height and width of the alveolar crest. This technique, however, is not typically used for lengthening the perimeter of the dental arch or improving teeth axes. We applied alveolar distraction in a tooth-borne manner in the second stage of our original method and obtained favorable results. We therefore present an outline of this method. Genioplasty was first performed to create an infrastructure for sequential advancement of the subapical alveolar segment. After bone union, anterior subapical alveolar osteotomy was performed. The stump of the osteotomized dentate segment was moved forward without changing the incisal edge position, and a box-type bioabsorbable plate with four holes was fixed only onto the dentate segment using two screws. After a latency period, two distraction devices were placed bilaterally to the brackets and activated at 1.0 mm/day. After reaching the desired position, the distractor was immobilized, and then replaced by resin temporary teeth to retain the created space. After the consolidation period, orthodontic treatment was restarted and teeth moved into the newly created space. Bimaxillary surgery was performed after completing pre-surgical orthodontic treatment. Finally, both desirable occlusion and functional masticatory function were obtained. This tooth-borne distraction system is one applicable method for patients with skeletal class II and crowding of lower anterior teeth, achieving good results particularly in combination with our original method.

Tooth loss early in life suppresses neurogenesis and synaptophysin expression in the hippocampus and impairs learning in mice.

Science.gov (United States)

Kubo, Kin-Ya; Murabayashi, Chika; Kotachi, Mika; Suzuki, Ayumi; Mori, Daisuke; Sato, Yuichi; Onozuka, Minoru; Azuma, Kagaku; Iinuma, Mitsuo

2017-02-01

Tooth loss induced neurological alterations through activation of a stress hormone, corticosterone. Age-related hippocampal morphological and functional changes were accelerated by early tooth loss in senescence-accelerated mouse prone 8 (SAMP8). In order to explore the mechanism underlying the impaired hippocampal function resulting from early masticatory dysfunction due to tooth loss, we investigated the effects of early tooth loss on plasma corticosterone levels, learning ability, neurogenesis, and synaptophysin expression in the hippocampus later in life of SAMP8 mice. We examined the effects of tooth loss soon after tooth eruption (1 month of age) on plasma corticosterone levels, learning ability in the Morris water maze, newborn cell proliferation, survival and differentiation in the hippocampal dentate gyrus, and synaptophysin expression in the hippocampus of aged (8 months of age) SAMP8 mice. Aged mice with early tooth loss exhibited increased plasma corticosterone levels, hippocampus-dependent learning deficits in the Morris water maze, decreased cell proliferation, and cell survival in the dentate gyrus, and suppressed synaptophysin expression in the hippocampus. Newborn cell differentiation in the hippocampal dentate gyrus, however, was not affected by early tooth loss. These findings suggest that learning deficits in aged SAMP8 mice with tooth loss soon after tooth eruption are associated with suppressed neurogenesis and decreased synaptophysin expression resulting from increased plasma corticosterone levels, and that long-term tooth loss leads to impaired cognitive function in older age. Copyright © 2016. Published by Elsevier Ltd.

Three-dimensional analysis of tooth dimensions in the MSX1-missense mutation

NARCIS (Netherlands)

Creton, Marijn; van den Boogaard, Marie-Jose; Maal, Thomas; Verhamme, Luc; Fennis, Willem; Carels, Carine; Kuijpers-Jagtman, Anne Marie; Cune, Marco

A novel, 3D technique to measure the differences in tooth crown morphology between the MSX1 cases and non-affected controls was designed to get a better understanding of dental phenotype-genotype associations. Eight Dutch subjects from a single family with tooth agenesis, all with an established

Recent Approaches in Tooth Engineering Research

Czech Academy of Sciences Publication Activity Database

Švandová, Eva; Veselá, Barbora; Křivánek, J.; Hampl, A.; Matalová, Eva

2014-01-01

Roč. 60, Suppl 1 (2014), s. 21-29 ISSN 0015-5500 R&D Projects: GA ČR GAP304/11/1418; GA MZd(CZ) NT11420 Institutional support: RVO:67985904 Keywords : engineering * tooth * stem cells * culture techniques Subject RIV: EA - Cell Biology Impact factor: 1.000, year: 2014

Comparison of Three types of Tooth Brushes on Plaque and Gingival Indices: A Randomized Clinical Trial.

Science.gov (United States)

Moeintaghavi, Amir; Sargolzaie, Naser; Rostampour, Mehrnoosh; Sarvari, Sara; Kargozar, Sanaz; Gharaei, Shideh

2017-01-01

To compare clinical results of three types of manual tooth brushes on plaque removal efficacy and gingivitis. This study is a single blind randomized trial with crossover design which involved 30 periodontaly healthy individuals. Professional plaque removal and oral hygiene instruction were performed for all the participants in the first step of our study followed by asking them to avoid brushing for 2 days. Thereafter plaque and gingivitis scores were measured using plaque and gingival indices (PI and GI). Then subjects were instructed to use Pulsar tooth brush for a two-week period and then, GI and PI indices were assessed again. After passing one-week period for wash out, subjects didn't brush for 2 days and indices were recorded again. The same procedure was done for CrossAction, and Butler 411 tooth brushes respectively and at the end of the study these variables were analyzed using SPSS software ver.16. Repeated measurement ANOVA test was used to compare the scores between different brushes. Finding of this study reveals that using all three types of tooth brushes resulted in significant plaque and gingivitis reduction compared to baseline levels. Pulsar tooth brush was significantly more effective in diminishing PI and GI than Butler tooth brush (p=0.044 and 0.031 respectively). According to our findings all 3 types of tooth brushes are effective in reduction of plaque and gingivitis and this reduction is significantly greater for Pulsar tooth brush compared to Butler and CrossAction tooth brushes.

Clinical evaluation of two-stage mandibular wisdom tooth extraction method to avoid mental nerve paresthesia

International Nuclear Information System (INIS)

Nozoe, Etsuro; Nakamura, Yasunori; Okawachi, Takako; Ishihata, Kiyohide; Shinnakasu, Mana; Nakamura, Norifumi

2011-01-01