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Sample records for affects tooth development

  1. 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.

  2. 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.

  3. In utero and lactational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) affects tooth development in rhesus monkeys

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Iku; Kazuhiro, Tsuga; Yasumasa, Akagawa [Hiroshima Univ. (Japan); Mineo, Yasuda; Hiroshi, Sumida [Hiroshima International Univ. (Japan); Akihiro, Arima; Toshio, Ihara [Shin Nippon Biomedical Laboratories, Ltd., Kagoshima (Japan); Shunichiro, Kubota [Tokyo Univ. (Japan); Kazuo, Asaoka [Kyoto Univ., Inuyama (Japan). Primate Research Institute; Takumi, Takasuga [Shimadzu Techno-Research Inc., Kyoto (Japan)

    2004-09-15

    The current tolerable daily intake (TDI) of dioxin and dioxin related compounds has been set at 4 pg TEQ/kg/day in Japan. This value was calculated from the lowest-observed-adverse-effect level (LOAEL) in experimental animals, mostly rodents. Gray et al. reported that a single oral dose of 200 ng/kg of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to pregnant rats on day 15 of gestation resulted in abnormalities of reproductive organs in the offspring. The maternal body burden at this dose was measured to be 86 ng/kg. To attain this body burden level, human daily intake was calculated to be 43.6 pg/kg/day. An uncertainty factor of 10 was applied to this value, and the human TDI was established. However, due to great differences in the biological half life of TCDD between human and rodents, the validity of this calculation is questioned. To obtain more reliable LOAEL in the second generation, we initiated a long-term study in rhesus monkeys in 1999. In rodents, teeth are known to be targets of developmental toxicity of dioxin. In utero and lactational TCDD exposure affects rat incisor and molar development. In humans also tooth abnormalities were reported among populations exposed to dioxins. In our monkey experiment, some young were stillborn or died neonatally. These animals provided us with a unique opportunity to study tooth development in primate young exposed to TCDD in utero and lactationally. By macroscopic observation we found some tooth abnormalities among died young exposed to TCDD5. This prompted us to examine surviving young by radiography. This is an interim report of our findings in these young.

  4. ClC-7 Deficiency Impairs Tooth Development and Eruption

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    Wang, He; Pan, Meng; Ni, Jinwen; Zhang, Yanli; Zhang, Yutao; Gao, Shan; Liu, Jin; Wang, Zhe; Zhang, Rong; He, Huiming; Wu, Buling; Duan, Xiaohong

    2016-01-01

    CLCN7 gene encodes the voltage gated chloride channel 7 (ClC-7) in humans. The mutations in CLCN7 have been associated with osteopetrosis in connection to the abnormal osteoclasts functions. Previously, we found that some osteopetrosis patients with CLCN7 mutations suffered from impacted teeth and root dysplasia. Here we set up two in vivo models under a normal or an osteoclast-poor environment to investigate how ClC-7 affects tooth development and tooth eruption. Firstly, chitosan-Clcn7-siRNA nanoparticles were injected around the first maxillary molar germ of newborn mice and caused the delay of tooth eruption and deformed tooth with root dysplasia. Secondly, E13.5 molar germs infected with Clcn7 shRNA lentivirus were transplanted under the kidney capsule and presented the abnormal changes in dentin structure, periodontal tissue and cementum. All these teeth changes have been reported in the patients with CLCN7 mutation. In vitro studies of ameloblasts, odontoblasts and dental follicle cells (DFCs) were conducted to explore the involved mechanism. We found that Clcn7 deficiency affect the differentiation of these cells, as well as the interaction between DFCs and osteoclasts through RANKL/OPG pathway. We conclude that ClC-7 may affect tooth development by directly targeting tooth cells, and regulate tooth eruption through DFC mediated osteoclast pathway. PMID:26829236

  5. ClC-7 Deficiency Impairs Tooth Development and Eruption.

    Science.gov (United States)

    Wang, He; Pan, Meng; Ni, Jinwen; Zhang, Yanli; Zhang, Yutao; Gao, Shan; Liu, Jin; Wang, Zhe; Zhang, Rong; He, Huiming; Wu, Buling; Duan, Xiaohong

    2016-02-01

    CLCN7 gene encodes the voltage gated chloride channel 7 (ClC-7) in humans. The mutations in CLCN7 have been associated with osteopetrosis in connection to the abnormal osteoclasts functions. Previously, we found that some osteopetrosis patients with CLCN7 mutations suffered from impacted teeth and root dysplasia. Here we set up two in vivo models under a normal or an osteoclast-poor environment to investigate how ClC-7 affects tooth development and tooth eruption. Firstly, chitosan-Clcn7-siRNA nanoparticles were injected around the first maxillary molar germ of newborn mice and caused the delay of tooth eruption and deformed tooth with root dysplasia. Secondly, E13.5 molar germs infected with Clcn7 shRNA lentivirus were transplanted under the kidney capsule and presented the abnormal changes in dentin structure, periodontal tissue and cementum. All these teeth changes have been reported in the patients with CLCN7 mutation. In vitro studies of ameloblasts, odontoblasts and dental follicle cells (DFCs) were conducted to explore the involved mechanism. We found that Clcn7 deficiency affect the differentiation of these cells, as well as the interaction between DFCs and osteoclasts through RANKL/OPG pathway. We conclude that ClC-7 may affect tooth development by directly targeting tooth cells, and regulate tooth eruption through DFC mediated osteoclast pathway.

  6. Apoptotic cell elimination during early tooth development

    Czech Academy of Sciences Publication Activity Database

    Matalová, Eva; Míšek, Ivan; Chovancová, Eva

    2003-01-01

    Roč. 72, č. 7 (2003), s. 34 ISSN 0001-7213. [Congress of the European Association of Veterinary Anatomists/24./. 21.07.2002-25.07.2002, Brno] R&D Projects: GA ČR GP204/02/P112 Institutional research plan: CEZ:AV0Z5045916 Keywords : tooth development Subject RIV: FF - HEENT, Dentistry

  7. Molecular basis of tooth germ development

    Czech Academy of Sciences Publication Activity Database

    Fleischmannová, Jana; Krejčí, P.; Matalová, Eva; Míšek, Ivan

    2007-01-01

    Roč. 16, č. 4 (2007), s. 39-46 ISSN 1210-4272 R&D Projects: GA AV ČR KJB500450503; GA MŠk OC B23.001 Institutional research plan: CEZ:AV0Z50450515 Keywords : tooth germ development Subject RIV: FF - HEENT, Dentistry

  8. Single-tooth replacement: factors affecting different prosthetic treatment modalities.

    Science.gov (United States)

    Al-Quran, Firas A; Al-Ghalayini, Raed F; Al-Zu'bi, Bashar N

    2011-12-21

    The choice between several treatment options for replacing a single missing tooth is influenced by clinical, dentist- and patient-immanent factors. This study aimed to determine the patient factors that would affect the treatment decision to replace a single missing tooth and to assess the satisfaction with several options. 200 volunteers involved (121 females and 79 males) divided into four groups, Group A: consisted of patients with conventional fixed partial dentures or patients with resin bonded fixed partial dentures. Group B: consisted of patients who received removable partial dentures while Group C: consisted of patients who received a single implant supported crown, and a control group D: consisted of patients who received no treatment. Data were collected using a questionnaire. The highest percentage of males within groups (58%) was within the removable prostheses category. The majority of the subjects in the study reported that the main reason for replacing a missing tooth was for esthetic and function. Most important factor affecting the choice between treatment modalities was damaging the neighboring teeth. Pain, post operative sensitivity and dental phobia were important factors in choosing the prosthesis type and affected the control group patients not to have any treatment. The highest satisfaction percentage among groups studied was recorded for dental implants then FPD groups, while the least percentage were in both the control and RPD groups, for all aspects of function, esthetic and speech efficiency. The final choice between FPD, RPD and implant depended on several factors which affected the decision making; among these is cost and patients' awareness of the different treatment options.

  9. Single-tooth replacement: factors affecting different prosthetic treatment modalities

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    Al-Quran Firas A

    2011-12-01

    Full Text Available Abstract Background The choice between several treatment options for replacing a single missing tooth is influenced by clinical, dentist- and patient-immanent factors. This study aimed to determine the patient factors that would affect the treatment decision to replace a single missing tooth and to assess the satisfaction with several options. Method 200 volunteers involved (121 females and 79 males divided into four groups, Group A: consisted of patients with conventional fixed partial dentures or patients with resin bonded fixed partial dentures. Group B: consisted of patients who received removable partial dentures while Group C: consisted of patients who received a single implant supported crown, and a control group D: consisted of patients who received no treatment. Data were collected using a questionnaire. Results The highest percentage of males within groups (58% was within the removable prostheses category. The majority of the subjects in the study reported that the main reason for replacing a missing tooth was for esthetic and function. Most important factor affecting the choice between treatment modalities was damaging the neighboring teeth. Pain, post operative sensitivity and dental phobia were important factors in choosing the prosthesis type and affected the control group patients not to have any treatment. The highest satisfaction percentage among groups studied was recorded for dental implants then FPD groups, while the least percentage were in both the control and RPD groups, for all aspects of function, esthetic and speech efficiency. Conclusions The final choice between FPD, RPD and implant depended on several factors which affected the decision making; among these is cost and patients' awareness of the different treatment options.

  10. Expression of Sox genes in tooth development.

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    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.

  11. Regional odontodysplasia: A case of progressive tooth development

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    R Ganguly

    2012-01-01

    Full Text Available Regional odontodysplasia (RO is considered a relatively rare dental anomaly despite increasing numbers of case reports in recent years. It usually presents as a localized anomaly in tooth development affecting a few adjacent teeth in a single maxillary or mandibular quadrant. The purpose of this paper is to describe an uncommon case of regional odotodysplasia involving noncontiguous mandibular teeth, crossing the midline in a male patient, and showing progressive normalization of tooth anatomy over a period of 6 years. Typically, teeth affected with RO become pulpally involved early on and are either extracted or endodontically treated. Such reports of automatic normalization over time in RO is supportive of a more conservative treatment approach.

  12. Hedgehog signaling is required at multiple stages of zebrafish tooth development

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    Stock David W

    2010-11-01

    Full Text Available Abstract Background The accessibility of the developing zebrafish pharyngeal dentition makes it an advantageous system in which to study many aspects of tooth development from early initiation to late morphogenesis. In mammals, hedgehog signaling is known to be essential for multiple stages of odontogenesis; however, potential roles for the pathway during initiation of tooth development or in later morphogenesis are incompletely understood. Results We have identified mRNA expression of the hedgehog ligands shha and the receptors ptc1 and ptc2 during zebrafish pharyngeal tooth development. We looked for, but did not detect, tooth germ expression of the other known zebrafish hedgehog ligands shhb, dhh, ihha, or ihhb, suggesting that as in mammals, only Shh participates in zebrafish tooth development. Supporting this idea, we found that morphological and gene expression evidence of tooth initiation is eliminated in shha mutant embryos, and that morpholino antisense oligonucleotide knockdown of shha, but not shhb, function prevents mature tooth formation. Hedgehog pathway inhibition with the antagonist compound cyclopamine affected tooth formation at each stage in which we applied it: arresting development at early stages and disrupting mature tooth morphology when applied later. These results suggest that hedgehog signaling is required continuously during odontogenesis. In contrast, over-expression of shha had no effect on the developing dentition, possibly because shha is normally extensively expressed in the zebrafish pharyngeal region. Conclusion We have identified previously unknown requirements for hedgehog signaling for early tooth initiation and later morphogenesis. The similarity of our results with data from mouse and other vertebrates suggests that despite gene duplication and changes in the location of where teeth form, the roles of hedgehog signaling in tooth development have been largely conserved during evolution.

  13. Variables affecting orthodontic tooth movement with clear aligners.

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    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.

  14. Caspase-7 in molar tooth development

    Czech Academy of Sciences Publication Activity Database

    Matalová, Eva; Vanden Berghe, T.; Švandová, Eva; Vandenabeele, P.; Healy, C.; Sharpe, P. T.; Tucker, A. S.

    2012-01-01

    Roč. 57, č. 11 (2012), s. 1474-1481 ISSN 0003-9969 R&D Projects: GA AV ČR IAA600450904 Grant - others:GA ČR(CZ) GAP502/12/1285 Program:GA Institutional research plan: CEZ:AV0Z50450515 Keywords : tooth * apoptosis * mineralisation Subject RIV: FF - HEENT, Dentistry Impact factor: 1.549, year: 2012

  15. 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.

  16. Optimum Design of the Involute-Cycloid Composite Tooth Profile Helical Gear

    OpenAIRE

    Tutulan, Florin G.; Nagamura, Kazuteru; Ikejo, Kiyotaka

    2004-01-01

    The tooth bending and tooth contact strengths of the involute-cycloid composite tooth profile helical gear, which was developed as a non-involute tooth profile gear based on cycloid tooth profile, are directly affected by its tooth profile. The involute-cycloid composite tooth profile curve changes with some design parameters such as pressure angle and radius of rolling circle. In this study, we developed a method to calculate the tooth root stress and the tooth contact stress of the involute...

  17. Factors Affecting Tooth Retention among Adult Population of Dharwad District, India.

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    Mulla, Salma H; Inamdar, Nurul Ameen; Prasad, K V V

    2016-11-01

    Oral health in relation to general health is influen-ced by the retention of teeth. Understanding factors affecting tooth retention will help health and social policy-makers to translate the knowledge on tooth retention into action programs for improving oral health of the people and hence enhance tooth retention. The aim of the present study was to determine the factors affecting tooth retention among adult population of Dharwad district, India. A cross-sectional survey of 1100 subjects (616 urban and 484 rural) residing in Dharwad district, Karnataka, India, was conducted. Self-designed questionnaire was prepared and data were collected on socio-demographic factors, oral hygiene practices, diet practices, adverse oral habits and frequency of dental visits by the interview method and clinical examination. Statistical analysis was carried out by applying one way analysis of variance (ANOVA), unpaired t-test and backward stepwise multiple regression. Karl Pearson's correlation coefficient was used to test the correlation between the two quantitative variables. A total of 66.72% subjects retained all 28 teeth and mean number of teeth retained by the study subjects were 25.33 (90.46%). There was gradual reduction in tooth retention with increase in age. Males (95.8%) compared to females (94.07%), unmarried (98.8%) than married subjects (93.3%) and subjects with intermediate or post high school diploma (97.5%) than those who were illiterate (89.5%) and other low educational level study subjects retained more teeth. Further mean values of tooth retention for other socio demographic factors i.e., occupation, income and family size were not statistically significant (p≤0.05). In addition, subjects using tooth brush (96.6%) and tooth paste (96.6%) for cleaning the teeth, subjects practicing mixed diet (96.6%) and subjects who never visited the dentist (96.5%) in their lifetime showed statistically significant greater tooth retention than study subjects who visited the

  18. Prevalence of delayed tooth development and its relation to tooth agenesis in Korean children.

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    Park, Min Kyoung; Shin, Min Kyung; Kim, Seong Oh; Lee, Hyo Seol; Lee, Jae-Ho; Jung, Han-Sung; Song, Je Seon

    2017-01-01

    The aim of this study was to investigate the epidemiology of delayed tooth development (DTD) and the link between DTD and tooth agenesis (TA). The dental maturity of all of the developing permanent teeth of 4611 children (2417 males and 2194 females) was evaluated from panoramic radiographs. The prevalence of DTD and TA was analyzed, and gender difference for DTS and TA was investigated. The correlation of DTD and TA was investigated in intra-fields and inter-fields. The total prevalence of DTD among the 4611 children was 3.40%. The maxillary second premolar was the most frequently delayed tooth (1.02%), followed by the maxillary second molar (0.88%) and the mandibular second premolar (0.74%). DTD significantly correlated with TA in both intra-fields and inter-fields (p<0.05). The field of delayed development exhibited a significant correlation with that of TA. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. The development of complex tooth shape in reptiles

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    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.

  20. Factors Affecting Oral Hygiene and Tooth Brushing in Preschool Children, Shiraz/Iran.

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    S, Shaghaghian; M, Zeraatkar

    2017-06-01

    Inadequate tooth brushing and inappropriate oral hygiene can lead to dental caries, the most common chronic diseases of childhood with several side effects. To evaluate factors affecting on preschool children's oral hygiene and tooth brushing in Shiraz, Iran. In this cross-sectional study, we selected 453 children registered in Shiraz kindergartens in 2013 by randomized cluster sampling. The children's tooth brushing and oral hygiene were assessed using a reliable and valid questionnaire and Simplified Debris Index (DI-S), respectively. A dental student examined all the children in each kindergarten to determine their DI-S. The relationship between the children's demographic variables and their oral hygiene and tooth brushing status were evaluated. Tooth brushing for 272 children (71.2%) had been started after the age of 2 years. The teeth in 96 children (24.2%) had been brushed lower than once daily. The mean of the children's DI-S was 1.19 ± (0.77). The DI-S of only 126 children (31.8%) was found to be good and very good. After controlling the effect of confounding factors, we found that the children's tooth brushing frequency was significantly associated with the number of children in the family and mothers' employment status. The age at which tooth brushing had been started was significantly associated with the fathers' education. Furthermore, the DI-S was associated with children's age, number of the children in the family, and their mothers' education. Oral hygiene and tooth brushing of the preschool children were not in a desirable status. Interventional procedures, especially educational programs, are recommended for children and their parents. These programs seem to be more necessary for older children, low socioeconomic families, and families with more than one child.

  1. Factors Affecting Oral Hygiene and Tooth Brushing in Preschool Children, Shiraz/Iran

    Science.gov (United States)

    S, Shaghaghian; M, Zeraatkar

    2017-01-01

    Statement of Problem: Inadequate tooth brushing and inappropriate oral hygiene can lead to dental caries, the most common chronic diseases of childhood with several side effects. Objectives: To evaluate factors affecting on preschool children’s oral hygiene and tooth brushing in Shiraz, Iran Materials and Methods: In this cross-sectional study, we selected 453 children registered in Shiraz kindergartens in 2013 by randomized cluster sampling. The children’s tooth brushing and oral hygiene were assessed using a reliable and valid questionnaire and Simplified Debris Index (DI-S), respectively. A dental student examined all the children in each kindergarten to determine their DI-S. The relationship between the children’s demographic variables and their oral hygiene and tooth brushing status were evaluated. Results: Tooth brushing for 272 children (71.2%) had been started after the age of 2 years. The teeth in 96 children (24.2%) had been brushed lower than once daily. The mean of the children’s DI-S was 1.19 ± (0.77). The DI-S of only 126 children (31.8%) was found to be good and very good. After controlling the effect of confounding factors, we found that the children’s tooth brushing frequency was significantly associated with the number of children in the family and mothers’ employment status. The age at which tooth brushing had been started was significantly associated with the fathers’ education. Furthermore, the DI-S was associated with children’s age, number of the children in the family, and their mothers’ education. Conclusions: Oral hygiene and tooth brushing of the preschool children were not in a desirable status. Interventional procedures, especially educational programs, are recommended for children and their parents. These programs seem to be more necessary for older children, low socioeconomic families, and families with more than one child. PMID:28959771

  2. Administration of the bisphosphonate zoledronic acid during tooth development inhibits tooth eruption and formation and induces dental abnormalities in rats.

    Science.gov (United States)

    Hiraga, Toru; Ninomiya, Tadashi; Hosoya, Akihiro; Nakamura, Hiroaki

    2010-06-01

    Bisphosphonates (BPs) are potent inhibitors of osteoclastic bone resorption and widely used for the treatment of osteoporosis and metastatic bone diseases. Recently, BPs have also been shown to benefit children with primary and secondary osteoporosis, including osteogenesis imperfecta; however, their long-term safety has not been established yet. Clinical and experimental studies have demonstrated that BPs delay or inhibit tooth eruption. The failure of tooth eruption causes several dental abnormalities. In this study, to determine the effects of BPs on tooth formation, the BP zoledronic acid (ZOL) was injected into 7- and 14-day-old rats, and the development of the mandibular teeth was examined. X-ray analysis demonstrated that ZOL inhibited the eruption of both incisors and molars and their formation, especially in the molar roots. Histological examination showed that, in ZOL-treated animals, alveolar bone remained unresorbed around tooth crowns, which injured ameloblasts and enamel matrix, leading to defects of the enamel. Furthermore, haphazard proliferation of odontogenic epithelium and mesenchyme associated with primitive tooth structures, which resembles human odontomas, was induced at the basal end of incisors but not around the molars. Tooth ankylosis to alveolar bone was occasionally observed in molars. These results suggest that administration of BPs during tooth development has the potential to inhibit tooth eruption and formation and to induce several types of dental abnormalities, which may be attributed to the altered osteoclastic activities.

  3. Limb, tooth, beak: Three modes of development and evolutionary ...

    Indian Academy of Sciences (India)

    Here we compare the embryological processes that shape the vertebrate limb bud, the mammalian tooth and the avian beak. The implied notion of development in the standard evolutionary picture is met only in the case of the vertebrate limb, a single-primordium organ with morphostatic shaping, in which cells rearrange in ...

  4. Three-dimensional mammalian tooth development using diceCT.

    Science.gov (United States)

    Nasrullah, Qamariya; Renfree, Marilyn B; Evans, Alistair R

    2018-01-01

    This study aims to develop the Diffusible Iodine-based Contrast-Enhanced CT (diceCT) method for non-destructive imaging of both soft and mineralised tissues. We sought to document the 3D spatio-temporal pattern of mammalian tooth development including multiple tooth classes and generations, using the tammar wallaby (Macropus eugenii) as a model species. We took microCT scans of developing fetuses and pouch young stained using Lugol's Iodine (I 2 KI) contrast agent. Stained versus unstained specimen comparisons were then made to investigate whether staining had improved visualisation of structures. Scan slices were compared to histological sections to confirm the identity of tissues and structures. Tissue layers were digitally segmented to create 3D models. DiceCT dramatically enhanced visual contrast of soft tissues, allowing differentiation between epithelial and mesenchymal layers. Subvolume scans at higher magnification achieved single-cell layer resolution within relatively large intact heads. We observed in-situ initiating teeth, which progressed through major stages of tooth development including morphogenesis and mineralisation. In addition, we traced the development of other mineralized and unmineralised tissues, such as the cranial bones and the brain, eye and olfactory system. DiceCT was time- and cost-effective in producing complex 3D models of the entire dentition of the tammar wallaby at each developmental stage with tissue-level resolution. The 3D view of soft and mineralised tooth structures allowed us to define tooth class and generation from a developmental perspective. Additionally, the development of other organs can also be documented using the same scans, demonstrating the efficiency and versatility of this technique. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Molar tooth development in caspase-3 deficient mice

    Czech Academy of Sciences Publication Activity Database

    Matalová, Eva; Sharpe, P. T.; Lakhani, S. A.; Roth, K. A.; Flavell, R. A.; Šetková, Jana; Míšek, Ivan; Tucker, A. S.

    2006-01-01

    Roč. 50, 5 (2006), s. 491-497 ISSN 0214-6282 R&D Projects: GA AV ČR KJB500450503; GA MŠk OC B23.001 Grant - others:European Molecular Biology Organization ASTF195.00-05; NIH NS41962 Institutional research plan: CEZ:AV0Z50450515 Keywords : tooth development * dental apoptosis * caspase-3 mutant Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.577, year: 2006

  6. 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.

  7. 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.

  8. Dental development and tooth agenesis in children with velocardiofacial syndrome.

    Science.gov (United States)

    Heliövaara, Arja; Rantanen, Irma; Arte, Sirpa

    2011-11-01

    BACKGROUND. Variations in dental development and tooth agenesis have been reported in children with velocardiofacial syndrome (VCFS). AIM. The aim was to evaluate the dental development and missing permanent teeth in children with VCFS. DESIGN. Forty-five children (23 girls) with VCFS who had visited the cleft palate and craniofacial centre were studied retrospectively from orthopantomograms taken at the mean age of 7.9 years (range 5.8-12.9). Thirteen of the children with VCFS had palatal clefts. The deletion of 22q11 was verified by FISH techniques. The dental stages were assessed by the method of Demirjian, and the dental age was calculated according to the Finnish dental maturity reference values. A paired Student's t-test was used in the statistical analysis. RESULTS. Eight children (17%), four with palatal clefts, had tooth agenesis. Four children (9%) had agenesis of mandibular incisors. The missing teeth (n = 19) were mainly mandibular incisors (n = 6), maxillary lateral incisors (n = 2), and maxillary second premolars (n = 4). The dental age of the children with VCFS was not different from their chronological age, but there was great individual variation. CONCLUSIONS. A high prevalence of missing permanent teeth, especially mandibular incisors, was observed. The need for thorough clinical and radiological dental examination in children with VCFS is emphasized. © 2011 The Authors. International Journal of Paediatric Dentistry © 2011 BSPD, IAPD and Blackwell Publishing Ltd.

  9. [Development of a screening scale for children at risk of baby bottle tooth decay].

    Science.gov (United States)

    Khadra-Eid, J; Baudet, D; Fourny, M; Sellier, E; Brun, C; François, P

    2012-03-01

    Baby bottle tooth decay is a severe form of early childhood caries. This study aims to elaborate a screening tool for at risk children in order to facilitate primary prevention. A case-control study was conducted among children suffering from baby bottle tooth decay and children with no dental caries. Cases were children aged 5 years or less at diagnosis who experienced at least four caries with one or more affecting maxillary incisors. Controls were children matched for age and sex. Parents were interviewed by phone about their child's exposure to potential risk factors. We included 88 children suffering from baby bottle tooth decay and 88 children with no dental caries. In multivariate analysis, low social class (OR 6.39 [95% CI, 1.45-28.11]), prolonged bottle feeding or bedtime feeding (OR 153.2 [95% CI, 11.77-1994.96]), and snacking (OR 5.94 [95% CI, 1.35-26.2]) were significantly associated with baby bottle tooth decay. Regular dental visits were a significant protecting factor (OR 0.13 [95% CI, 0.02-0.77]). A score was developed using these significant risk factors and tested on the survey population. The mean score was 13/20 for cases and 4/20 for controls. These results are in accordance with the literature, except for brushing teeth, which was not significantly associated with baby bottle tooth decay in our study. A screening scale with a score of 20 points was proposed. Future validation is required. Pediatricians and general practitioners should encourage parents to change their habits. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  10. Factors affecting nuclear development

    International Nuclear Information System (INIS)

    Stevens, G.H.; Girouard, P.

    1995-01-01

    Among the factors affecting nuclear development, some depend more or less on public authorities, but many are out of public authorities control (foreign policies, market and deregulation, socials and environmental impacts, public opinion). As far as possible, the following study tries to identify those factors. (D.L.). 2 photos

  11. Demographic, socioeconomic, and behavioral factors affecting patterns of tooth decay in the permanent dentition: principal components and factor analyses.

    Science.gov (United States)

    Shaffer, John R; Polk, Deborah E; Feingold, Eleanor; Wang, Xiaojing; Cuenco, Karen T; Weeks, Daniel E; DeSensi, Rebecca S; Weyant, Robert J; Crout, Richard; McNeil, Daniel W; Marazita, Mary L

    2013-08-01

    Dental caries of the permanent dentition is a multifactorial disease resulting from the complex interplay of endogenous and environmental risk factors. The disease is not easily quantitated due to the innumerable possible combinations of carious lesions across individual tooth surfaces of the permanent dentition. Global measures of decay, such as the DMFS index (which was developed for surveillance applications), may not be optimal for studying the epidemiology of dental caries because they ignore the distinct patterns of decay across the dentition. We hypothesize that specific risk factors may manifest their effects on specific tooth surfaces leading to patterns of decay that can be identified and studied. In this study, we utilized two statistical methods of extracting patterns of decay from surface-level caries data to create novel phenotypes with which to study the risk factors affecting dental caries. Intra-oral dental examinations were performed on 1068 participants aged 18-75 years to assess dental caries. The 128 tooth surfaces of the permanent dentition were scored as carious or not and used as input for principal components analysis (PCA) and factor analysis (FA), two methods of identifying underlying patterns without a priori knowledge of the patterns. Demographic (age, sex, birth year, race/ethnicity, and educational attainment), anthropometric (height, body mass index, waist circumference), endogenous (saliva flow), and environmental (tooth brushing frequency, home water source, and home water fluoride) risk factors were tested for association with the caries patterns identified by PCA and FA, as well as DMFS, for comparison. The ten strongest patterns (i.e. those that explain the most variation in the data set) extracted by PCA and FA were considered. The three strongest patterns identified by PCA reflected (i) global extent of decay (i.e. comparable to DMFS index), (ii) pit and fissure surface caries and (iii) smooth surface caries, respectively. The

  12. Corticotomy affects both the modus and magnitude of orthodontic tooth movement

    DEFF Research Database (Denmark)

    Verna, Carlalberta; Cattaneo, Paolo; Dalstra, Michel

    2018-01-01

    the tooth has been assumed to simulate the one occurring after corticotomy to increase tooth movement rate. Moment-to-force ratios corresponding to three different types of movements have been simulated; uncontrolled tipping, translation, and root movement. The three tooth movements have been analyzed......: 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...

  13. Corticotomy affects both the modus and magnitude of orthodontic tooth movement

    DEFF Research Database (Denmark)

    Verna, Carlalberta; Cattaneo, Paolo; Dalstra, Michel

    2017-01-01

    the tooth has been assumed to simulate the one occurring after corticotomy to increase tooth movement rate. Moment-to-force ratios corresponding to three different types of movements have been simulated; uncontrolled tipping, translation, and root movement. The three tooth movements have been analyzed......: 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....

  14. Beta-Catenin and Plakoglobin Expression during Zebrafish Tooth Development and Replacement.

    Directory of Open Access Journals (Sweden)

    Barbara Verstraeten

    Full Text Available We analyzed the protein distribution of two cadherin-associated molecules, plakoglobin and β-catenin, during the different stages of tooth development and tooth replacement in zebrafish. Plakoglobin was detected at the plasma membrane already at the onset of tooth development in the epithelial cells of the tooth. This pattern remained unaltered during further tooth development. The mesenchymal cells only showed plakoglobin from cytodifferentiation onwards. Plakoglobin 1a morpholino-injected embryos showed normal tooth development with proper initiation and differentiation. Although plakoglobin is clearly present during normal odontogenesis, the loss of plakoglobin 1a does not influence tooth development. β-catenin was found at the cell borders of all cells of the successional lamina but also in the nuclei of surrounding mesenchymal cells. Only membranous, not nuclear, β-catenin, was found during morphogenesis stage. However, during cytodifferentiation stage, both nuclear and membrane-bound β-catenin was detected in the layers of the enamel organ as well as in the differentiating odontoblasts. Nuclear β-catenin is an indication of an activated Wnt pathway, therefore suggesting a possible role for Wnt signalling during zebrafish tooth development and replacement.

  15. The Impact of the Eda Pathway on Tooth Root Development.

    Czech Academy of Sciences Publication Activity Database

    Fons Romero, J.M.; Star, H.; Lav, R.; Watkins, S.; Harrison, M.; Hovořáková, Mária; Headon, D.; Tucker, Abigail

    2017-01-01

    Roč. 96, č. 11 (2017), s. 1290-1297 ISSN 0022-0345 R&D Projects: GA ČR(CZ) GB14-37368G Institutional support: RVO:68378041 Keywords : tooth * ectodermal dysplasia * epithelium Subject RIV: EA - Cell Biology OBOR OECD: Developmental biology Impact factor: 4.755, year: 2016

  16. Expression patterns of genes critical for BMP signaling pathway in developing human primary tooth germs.

    Science.gov (United States)

    Dong, Xiuqing; Shen, Bin; Ruan, Ningsheng; Guan, Zhen; Zhang, Yanding; Chen, YiPing; Hu, Xuefeng

    2014-12-01

    The developing murine tooth has been used as an excellent model system to study the molecular mechanism of organ development and regeneration. While the expression patterns of numerous regulatory genes have been examined and their roles have begun to be revealed in the developing murine tooth, little is known about gene expression and function in human tooth development. In order to unveil the molecular mechanisms that regulate human tooth morphogenesis, we examined the expression patterns of the major BMP signaling pathway molecules in the developing human tooth germ at the cap and bell stages by in situ hybridization, immunohistochemistry, and real-time RT-PCR. Expression of BMP ligands and antagonist, including BMP2, BMP3, BMP4, BMP7, and NOOGGIN, exhibited uniform patterns in the tooth germs of incisor and molar at the cap and bell stages with stronger expression in the inner dental epithelium than that in the dental mesenchyme. Both type I and type II BMP receptors were present in widespread expression pattern in the whole-enamel organ and the dental mesenchyme with the strongest expression in inner dental epithelium at the cap and bell stages. SMAD4 and SMAD1/5/8 showed an expression pattern similar to that of BMP ligands with more intensive signals in the inner dental epithelium. Despite some unique and distinct patterns as compared to the mouse, the intensive expression of BMP signaling pathway molecules in the developing human tooth strongly suggests conserved functions of BMP signaling during human odontogenesis, such as in mediating tissue interactions and regulating differentiation and organization of odontogenic tissues. Our results provide an important set of documents for studying molecular regulatory mechanisms underlying tooth development and regeneration in humans.

  17. The Origin of Tooth Replacement : Three-dimensional Synchrotron Histology Visualizes the Dental Development of Silurian Stem Osteichthyans

    OpenAIRE

    Chen, Donglei

    2017-01-01

    Mechanisms of tooth replacement distribute incongruently among extant gnathostomes (jawed vertebrates): a permanent tooth-generating dental lamina exists in chondrichthyans (cartilaginous fish) and tetrapods but not teleosts, whereas tooth shedding by basal hard tissue resorption occurs in tetrapods and teleosts but not chondrichthyans. Theories about the evolution of tooth development have been biased towards the chondrichthyan conveyor-belt replacement, since there has been no fossil eviden...

  18. The Sirt6 gene: Does it play a role in tooth development?

    Directory of Open Access Journals (Sweden)

    Xueyang Liao

    Full Text Available Dental Mesenchymal Cells (DMCs are known to play a role in tooth development as well as in the repair and regeneration of dental tissue. A large number of signaling molecules regulate the proliferation and differentiation of DMC, though the underlying mechanisms are still not fully understood. Sirtuin-6 (SIRT6, a key regulator of aging, can exert an impact on embryonic stem cell (ESC differentiation. The experimental deletion of Sirt6 in mouse bone marrow cells has been found to have an inhibiting impact on the bone mineral density and the osteogenic differentiation of these cells. The possible role of Sirt6 in tooth development, however, has at present remained largely unexplored. In the present study, we found that SIRT6 had no effect on tooth development before birth. However, Sirt6 gene deletion in knockout mice did have two post-natal impacts: a delay in tooth eruption and sluggishness in the development of dental roots. We propose an explanation of the possible molecular basis of the changes observed in Sirt6-/- mice. SIRT6 is expressed in mouse odontoblasts. Sirt6 deletion enhanced the proliferation of DMCs, as well as their capacity for adipogenic differentiation. On the other hand, it inhibited their capacity for in vitro osteogenic/chondrogenic differentiation. Further studies suggested that other factors may mediate the role of Sirt6 in odontogenesis. These include the nuclear factor kappa B (NF-κB, p38 mitogen-activated protein kinase (p38-MAPK, extracellular regulated MAP kinase (ERK pathways and the mitochondrial energy. We demonstrated that Sirt6 plays a role in tooth root formation and confirmed that SIRT6 is necessary for DMC differentiation as well as for the development of the tooth root and for eventual tooth eruption. These results establish a new link between SIRT6 and tooth development.

  19. The Sirt6 gene: Does it play a role in tooth development?

    Science.gov (United States)

    Liao, Xueyang; Feng, Bo; Zhang, Demao; Liu, Peng; Zhou, Xuedong; Li, Ruimin; Ye, Ling

    2017-01-01

    Dental Mesenchymal Cells (DMCs) are known to play a role in tooth development as well as in the repair and regeneration of dental tissue. A large number of signaling molecules regulate the proliferation and differentiation of DMC, though the underlying mechanisms are still not fully understood. Sirtuin-6 (SIRT6), a key regulator of aging, can exert an impact on embryonic stem cell (ESC) differentiation. The experimental deletion of Sirt6 in mouse bone marrow cells has been found to have an inhibiting impact on the bone mineral density and the osteogenic differentiation of these cells. The possible role of Sirt6 in tooth development, however, has at present remained largely unexplored. In the present study, we found that SIRT6 had no effect on tooth development before birth. However, Sirt6 gene deletion in knockout mice did have two post-natal impacts: a delay in tooth eruption and sluggishness in the development of dental roots. We propose an explanation of the possible molecular basis of the changes observed in Sirt6-/- mice. SIRT6 is expressed in mouse odontoblasts. Sirt6 deletion enhanced the proliferation of DMCs, as well as their capacity for adipogenic differentiation. On the other hand, it inhibited their capacity for in vitro osteogenic/chondrogenic differentiation. Further studies suggested that other factors may mediate the role of Sirt6 in odontogenesis. These include the nuclear factor kappa B (NF-κB), p38 mitogen-activated protein kinase (p38-MAPK), extracellular regulated MAP kinase (ERK) pathways and the mitochondrial energy. We demonstrated that Sirt6 plays a role in tooth root formation and confirmed that SIRT6 is necessary for DMC differentiation as well as for the development of the tooth root and for eventual tooth eruption. These results establish a new link between SIRT6 and tooth development. PMID:28355287

  20. Genome-Wide Association Study Reveals Multiple Loci Associated with Primary Tooth Development during Infancy

    OpenAIRE

    Pillas, Demetris; Hoggart, Clive J.; Evans, David M.; O'Reilly, Paul F.; Sipil?, Kirsi; L?hdesm?ki, Raija; Millwood, Iona Y.; Kaakinen, Marika; Netuveli, Gopalakrishnan; Blane, David; Charoen, Pimphen; Sovio, Ulla; Pouta, Anneli; Freimer, Nelson; Hartikainen, Anna-Liisa

    2010-01-01

    Author Summary Genome-wide association studies have been used to identify genetic variants conferring susceptibility to diseases, intermediate phenotypes, and physiological traits such as height, hair color, and age at menarche. Here we analyze the NFBC1966 and ALSPAC birth cohorts to investigate the genetic determinants of a key developmental process: primary tooth development. The prospective nature of our studies allows us to exploit accurate measurements of age at first tooth eruption and...

  1. 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

  2. Radiographic evaluation of the fate of developing tooth buds on the fracture line of mandibular fractures.

    Science.gov (United States)

    Suei, Yoshikazu; Mallick, Parimal Chandra; Nagasaki, Toshikazu; Taguchi, Akira; Fujita, Minoru; Tanimoto, Keiji

    2006-01-01

    The goal was to suggest guidelines for the treatment of developing tooth buds located on the fracture line of mandibular fractures. The long-term radiographic follow-up records of 28 patients with mandibular fractures involving 66 tooth buds were examined for the occurrence of abnormalities in development or eruption. The fates of the involved teeth were compared according to the fracture conditions and other factors, and the cause of the abnormalities was surveyed. Abnormal findings were observed in 30 of 66 developing teeth (45%); these included deficient root formation, abnormal bend of the root, nodule formation on the root, partial obliteration of the pulp cavity, impaction, growth arrest, and external resorption. No relationship was found between the presence of abnormalities and the condition of the fracture or the developmental stage of the tooth buds. However, infection, rotation of the tooth bud, and a surgical wire passing through the follicular space were associated with arrested growth and impaction. The tooth buds present on the fracture line should be preserved except in cases of infection, and careful attention should be paid to avoiding further injury to the tooth bud and the soft tissues of the follicle at the time of surgery.

  3. Genome-Wide Association Study Reveals Multiple Loci Associated with Primary Tooth Development during Infancy

    Science.gov (United States)

    Sipilä, Kirsi; Lähdesmäki, Raija; Millwood, Iona Y.; Kaakinen, Marika; Netuveli, Gopalakrishnan; Blane, David; Charoen, Pimphen; Sovio, Ulla; Pouta, Anneli; Freimer, Nelson; Hartikainen, Anna-Liisa; Laitinen, Jaana; Vaara, Sarianna; Glaser, Beate; Crawford, Peter; Timpson, Nicholas J.; Ring, Susan M.; Deng, Guohong; Zhang, Weihua; McCarthy, Mark I.; Deloukas, Panos; Peltonen, Leena

    2010-01-01

    Tooth development is a highly heritable process which relates to other growth and developmental processes, and which interacts with the development of the entire craniofacial complex. Abnormalities of tooth development are common, with tooth agenesis being the most common developmental anomaly in humans. We performed a genome-wide association study of time to first tooth eruption and number of teeth at one year in 4,564 individuals from the 1966 Northern Finland Birth Cohort (NFBC1966) and 1,518 individuals from the Avon Longitudinal Study of Parents and Children (ALSPAC). We identified 5 loci at P<5×10−8, and 5 with suggestive association (P<5×10−6). The loci included several genes with links to tooth and other organ development (KCNJ2, EDA, HOXB2, RAD51L1, IGF2BP1, HMGA2, MSRB3). Genes at four of the identified loci are implicated in the development of cancer. A variant within the HOXB gene cluster associated with occlusion defects requiring orthodontic treatment by age 31 years. PMID:20195514

  4. Deletion of Osr2 Partially Rescues Tooth Development in Runx2 Mutant Mice.

    Science.gov (United States)

    Kwon, H J E; Park, E K; Jia, S; Liu, H; Lan, Y; Jiang, R

    2015-08-01

    Tooth organogenesis depends on genetically programmed sequential and reciprocal inductive interactions between the dental epithelium and neural crest-derived mesenchyme. Previous studies showed that the Msx1 and Runx2 transcription factors are required for activation of odontogenic signals, including Bmp4 and Fgf3, in the early tooth mesenchyme to drive tooth morphogenesis through the bud-to-cap transition and that Runx2 acts downstream of Msx1 to activate Fgf3 expression. Recent studies identified Osr2 as a repressor of tooth development and showed that inactivation of Osr2 rescued molar tooth morphogenesis in the Msx1(-/-) mutant mice as well as in mice with neural crest-specific inactivation of Bmp4. Here we show that Runx2 expression is expanded in the tooth bud mesenchyme in Osr2(-/-) mutant mouse embryos and is partially restored in the tooth mesenchyme in Msx1(-/-)Osr2(-/-) mutants in comparison with Msx1(-/-) and wild-type embryos. Whereas mandibular molar development arrested at the bud stage and maxillary molar development arrested at the bud-to-cap transition in Runx2(-/-) mutant mice, both mandibular and maxillary molar tooth germs progressed to the early bell stage, with rescued expression of Msx1 and Bmp4 in the dental papilla as well as expression of Bmp4, p21, and Shh in the primary enamel knot in the Osr2(-/-)Runx2(-/-) compound mutants. In contrast to the Msx1(-/-)Osr2(-/-) compound mutants, which exhibit nearly normal first molar morphogenesis, the Osr2(-/-)Runx2(-/-) compound mutant embryos failed to activate the expression of Fgf3 and Fgf10 in the dental papilla and exhibited significant deficit in cell proliferation in both the dental epithelium and mesenchyme in comparison with the control embryos. These data indicate that Runx2 synergizes with Msx1 to drive tooth morphogenesis through the bud-to-cap transition and that Runx2 controls continued tooth growth and morphogenesis beyond the cap stage through activation of Fgf3 and Fgf10 expression

  5. An evolutionary view on tooth development and replacement in wild Atlantic salmon (Salmo salar L.).

    Science.gov (United States)

    Huysseune, A; Witten, P E

    2008-01-01

    To gain an insight into the evolution of tooth replacement mechanisms, we studied the development of first-generation and replacement teeth on the dentary of wild Atlantic salmon (Salmo salar L.), a protacanthopterygian teleost, using serially sectioned heads of early posthatching stages as well as adults. First-generation teeth develop within the oral epithelium. The anlage of the replacement tooth is first seen as a placode-like thickening of the outer dental epithelium of the predecessor, at its lingual and caudal side. Ongoing development of the replacement tooth germ is characterized by the elaboration of a population of epithelial cells, termed here the middle dental epithelium, apposed to the inner dental epithelium on the lingual side of the tooth germ. Before the formation of the new successor, a single-layered outer dental epithelium segregates from the middle dental epithelium. The dental organs of the predecessor and the successor remain broadly interconnected. The absence of a discrete successional dental lamina in salmon stands in sharp contrast to what is observed in other teleosts, even those that share with salmon the extraosseous formation of replacement teeth. The mode of tooth replacement in Atlantic salmon displays several characters similar to those observed in the shark Squalus acanthias. To interpret similarities in tooth replacement between Atlantic salmon and chondrichthyans as a case of convergence, or to see them as a result of a heterochronic shift, requires knowledge on the replacement process in more basal actinopterygian lineages. The possibility that the middle dental epithelium functionally substitutes for a successional lamina, and could be a source of stem cells, whose descendants subsequently contribute to the placode of the new replacement tooth, needs to be explored.

  6. Dental Age Estimation (DAE): Data management for tooth development stages including the third molar. Appropriate censoring of Stage H, the final stage of tooth development.

    Science.gov (United States)

    Roberts, Graham J; McDonald, Fraser; Andiappan, Manoharan; Lucas, Victoria S

    2015-11-01

    The final stage of dental development of third molars is usually helpful to indicate whether or not a subject is aged over 18 years. A complexity is that the final stage of development is unlimited in its upper border. Investigators usually select an inappropriate upper age limit or censor point for this tooth development stage. The literature was searched for appropriate data sets for dental age estimation and those that provided the count (n), the mean (x¯), and the standard deviation (sd) for each of the tooth development stages. The Demirjian G and Demirjian H were used for this study. Upper and lower limits of the Stage G and Stage H data were calculated limiting the data to plus or minus three standard deviations from the mean. The upper border of Stage H was limited by appropriate censoring at the maximum value for Stage G. The maximum age at attainment from published data, for Stage H, ranged from 22.60 years to 34.50 years. These data were explored to demonstrate how censoring provides an estimate for the correct maximum age for the final stage of Stage H as 21.64 years for UK Caucasians. This study shows that confining the data array of individual tooth developments stages to ± 3sd provides a reliable and logical way of censoring the data for tooth development stages with a Normal distribution of data. For Stage H this is inappropriate as it is unbounded in its upper limit. The use of a censored data array for Stage H using Percentile values is appropriate. This increases the reliability of using third molar Stage H alone to determine whether or not an individual is over 18 years old. For Stage H, individual ancestral groups should be censored using the same technique. Copyright © 2015 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  7. Spatiotemporal expression of the homeobox gene S8 during mouse tooth development.

    Science.gov (United States)

    Karg, H; Burger, E H; Lyaruu, D M; Bronckers, A L; Wöltgens, J H

    1997-09-01

    The murine S8 gene encodes a nuclear homeodomain containing transcription factor that is expressed at sites of epithelial-mesenchymal interactions, including those in cranofacial tissues. The spatiotemporal expression of S8 mRNA was examined in tooth primordia by in situ hybridization. S8 transcripts were found in all stages of tooth development in 13- to 16.5-day-old mouse embryos (E13-E16.5), covering the early bud stage up to the late bell stage. S8 mRNA was found exclusively in the ectomesenchyme and its derivatives that originate from the neural crest: future pulp cells, odontoblast precursors and dental follicle cells. Expression was highest at the late cap and early bud stages and declined at the mid-bell stage, in both first molar and incisor primordia. In E13 jaw explants grown in organ culture for 48 h, S8 mRNA was still present in first and second molar primordia after culture. At E15.5, S8 mRNA was also transiently present in the surrounding osteogenic tissue. It is concluded that the distribution pattern of S8 mRNA during tooth development indicates a role for the gene in defining the identity of dental papilla and follicle cells. It is speculated that the time-restricted expression of S8 in tooth primordia involves establishing the definitive form of the tooth organ.

  8. Fate of developing tooth buds located in relation to mandibular fractures in three infancy cases.

    Science.gov (United States)

    Yamamoto, Kazuhiko; Matsusue, Yumiko; Murakami, Kazuhiro; Horita, Satoshi; Matsubara, Yuri; Kuraki, Miho; Kurihara, Miyako; Imai, Yuichiro; Sugiura, Tsutomu; Kirita, Tadaaki

    2010-08-01

    The fate of developing tooth buds located in relation to mandibular fractures was investigated in three infancy cases. Three infants, 2 girls and a boy, aged from 1 year and 5-months old to 2 years and 6-months old, were treated for dislocated mandibular fracture in the symphyseal region by manual reduction and fixation with a thermoforming splint and circumferential wiring under general anesthesia. Fracture healing was uneventful in all cases. A few years later, no obvious deformity of the jaw or malocclusion was observed; however, malformation of the crown was found in one of the permanent teeth on the fracture line in the first case. In the second case, no abnormality was observed in one of the permanent teeth on the fracture line, but the effect on the other tooth could not be evaluated due to abnormality of the tooth probably not related to the injury. In the third case, root formation was arrested in one of the permanent teeth on the fracture line and the tooth was lost early after eruption. The development of tooth buds on the fracture line is not predictable and therefore, should be monitored by regular follow up.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. Radiographic study of delayed tooth development in patients with dental agenesis.

    Science.gov (United States)

    Ruiz-Mealin, Erika V; Parekh, Susan; Jones, Steven P; Moles, David R; Gill, Daljit S

    2012-03-01

    The aims of this study were to compare the radiographic development of permanent teeth in a group of children affected by dental agenesis with an unaffected control group and to determine the effects of confounding factors including the severity of the dental agenesis, age, sex, ethnicity, and the number of stages used to estimate dental age. A single-center retrospective cross-sectional study of dental panoramic tomographs was undertaken between July 2007 and April 2008 in a postgraduate teaching school. A total of 139 patients (aged 9-18 years) were recruited from the orthodontic clinic on the basis of predetermined inclusion and exclusion criteria to either a dental agenesis group or a control group. Dental panoramic tomograms were assessed, and the stages of development of the permanent teeth in the left maxillary and left mandibular regions were scored by using the 12 stages of Haavikko and the 8 stages of Demirjian and Goldstein. For each tooth scored, the mean dental age and standard error were determined by using the dental age assessment method, and an estimated dental age for each subject was derived by using the weighted average method. A statistically significant delay in dental age was found in the patients with dental agenesis compared with the control group. The dental age assessment method of Haavikko showed a delay of 1.20 years (SD, 1.74), and the method of Demirjian and Goldstein showed a delay of 1.64 years (SD, 1.75). It was also observed that older patients with dental agenesis had greater delays in tooth formation (P dental age increased by 0.53 year; with the Demirjian and Goldstein method, the delay increased by 0.48 year. A significant association was seen between the severity of dental agenesis and the delay in dental age (P dental age was delayed by 0.13 year (lower confidence interval, -0.22; upper confidence interval, 0.35). There was no evidence that sex or ethnicity has an effect on the delay in dental age in patients with dental

  11. Does erosive tooth wear affect the oral health-related quality of life of preschool children?

    OpenAIRE

    TELLO, Gustavo; OLIVEIRA, Luciana Butini; MURAKAMI, Christiana; BONINI, Gabriela Cunha; ABANTO, Jenny; BÖNECKER, Marcelo

    2017-01-01

    ABSTRACT Objective: The aim of this study was to investigate the impact of erosive tooth wear on the Oral Health-Related Quality of life (OHRQoL) of preschool children. Methods: Dental examinations were conducted on 815 children aged 3-4 years during the Children’s Vaccination National Day when their parents were also invited to answer the Brazilian Early Childhood Oral Health Impact Scale (B-ECOHIS). ETW prevalence and severity were measured using a modified version of the O’Brien index (1...

  12. Micro-tensile bond strength of sound and caries-affected primary tooth dentin measured with original designed jig.

    Science.gov (United States)

    Hosoya, Yumiko; Kawada, Eiji; Ushigome, Toshiaki; Oda, Yutaka; Garcia-Godoy, Franklin

    2006-05-01

    To measure the micro-tensile bond strength (MTBS) on sound and caries-affected primary tooth dentin using an original designed jig that was developed for making symmetric and uniformly-sized specimens for the micro-tensile strength testing. The MTBS of dumbbell-shaped specimens and matchstick-shaped specimens were measured. Dumbbell-shaped specimens: The occlusal surfaces of 15 sound primary molars were ground with a water-cooled air turbine using a diamond bur. The adhesive systems and resin-based composites were Clearfil SE Bond and Clearfil AP-X (SE group) and Single Bond and Z250 (SB group). Matchstick-shaped specimens: Sixteen primary molars (5 sound and 11 carious) were used. The occlusal surfaces of sound teeth were ground with a water-cooled air turbine using a diamond bur. Infected dentin was determined by a caries detecting dye solution and removed with a round-shaped steel bur under water-cooling and with a hand instrument. SE was applied. Data was statistically analyzed using ANOVA and Fisher's PLSD at p < 0.05. The MTBSs (MPa) for the dumbbell-shaped specimens were 8.9 +/- 7.0 in the SE group and 10.3 +/- 5.8 in the SB group and that for the matchstick-shaped specimens were 9.0 +/- 6.3 in the sound-SE group and 9.2 +/- 5.8 in the carious-SE group. No significant difference was observed among them. (c) 2005 Wiley Periodicals, Inc.

  13. Vascular endothelial growth factor and nitric oxide synthase expression in human tooth germ development.

    Science.gov (United States)

    Mastrangelo, F; Sberna, M T; Tettamanti, L; Cantatore, G; Tagliabue, A; Gherlone, E

    2016-01-01

    Vascular Endothelia Growth Factor (VEGF) and Nitric Oxide Synthase (NOS) expression, were evaluated in human tooth germs at two different stages of embryogenesis, to clarify the role of angiogenesis during tooth tissue differentiation and growth. Seventy-two third molar germ specimens were selected during oral surgery. Thirty-six were in the early stage and 36 in the later stage of tooth development. The samples were evaluated with Semi-quantitative Reverse Transcription-Polymerase chain Reaction analyses (RT-PcR), Western blot analysis (WB) and immunohistochemical analysis. Western blot and immunohistochemical analysis showed a VEGF and NOS 1-2-3 positive reaction in all samples analysed. VEGF high positive decrease reaction was observed in stellate reticulum cells, ameloblast and odontoblast clusters in early stage compared to later stage of tooth germ development. Comparable VEGF expression was observed in endothelial cells of early and advanced stage growth. NOS1 and NOS3 expressions showed a high increased value in stellate reticulum cells, and ameloblast and odontoblast clusters in advanced stage compared to early stage of development. The absence or only moderate positive reaction of NOS2 was detected in all the different tissues. Positive NOS2 expression showed in advanced stage of tissue development compared to early stage. The action of VEGF and NOS molecules are important mediators of angiogenesis during dental tissue development. VEGF high positive expression in stellate reticulum cells in the early stage of tooth development compared to the later stage and the other cell types, suggests a critical role of the stellate reticulum during dental embryo-morphogenesis.

  14. Risk factors for developing tooth sensitivity and gingival irritation associated with nightguard vital bleaching.

    Science.gov (United States)

    Leonard, R H; Haywood, V B; Phillips, C

    1997-08-01

    The purpose of this study was to determine risk factors in the development of tooth sensitivity and gingival irritation associated with the nightguard vital bleaching technique. The potential risk factors evaluated (sex, age, reported allergy, whitening solution, number of times the solution was changed daily [its usage pattern], and dental arch) were collected from the daily log form turned in by each of the 64 participants after completion of the 6-week lightening process. Also evaluated for each participant, from color slides, were tooth characteristics such as gingival recession, defective restorations, abfraction lesions, enamel-cementum abrasion, etc, and reported side effects. The generalized Mantel-Haenszel statistic was used to assess the association between the potential risk factors and the development of tooth sensitivity and/or gingival irritation. No statistical relationship existed between age, sex, allergy, tooth characteristics, or the dental arch lightened and the development of side effects. Initially, a statistically significant association existed between side effects and the whitening solution used. However, when the analysis was controlled for usage pattern, this relationship disappeared. Patients who changed the whitening solution more than once a day reported statistically significantly more side effects than did those who did not change the whitening solution during their usage time.

  15. Patterns of Glycoconjugate Distribution during Molar Tooth Germ Development in Mice

    Directory of Open Access Journals (Sweden)

    AR. Varasteh

    2007-09-01

    Full Text Available Objective: The aim of the present study was to evaluate the structure and distribution of Glycoconjugates during molar tooth germ development in mice.Materials and Methods: Sixteen tooth germs were obtained from BALB/c mice embryos 15 to 18 days post-gestation and fixed in 10% formalin. After routine tissue processing, 5μm sections were cut and stained with BSA1-B4 and PNA using the lectin histochemical method. All slides were evaluated by light microscopy.Results: Both lectins showed positive reaction in the tooth germ but with spatiotemporal differences. During bell stage, the reaction was strong with BSA1-B4 but moderate with PNA. Strong PNA uptake was observed in the odontoblastic and ameloblastic nuclei alongwith the apical cytoplasm of the ameloblasts.Conclusion: Although the lectins that were used in the present study recognize the same terminal sugar residue, they reacted with different disaccharide sequences with various penaltomer sugars. Therefore it may be assumed that the pattern of affinity for different parts of the developing tooth germ such as ameloblasts and odontoblasts is different in various lectins.

  16. Tooth Fairy guilty of favouritism!

    Science.gov (United States)

    Patcas, Raphael; van Waes, Hubertus Jm; Daum, Moritz M; Landolt, Markus A

    2017-12-11

    To determine the proportion of children visited by the Tooth Fairy, the child-related factors that influence the likelihood of her visit, and the parent-related variables that affect the amount of money the Tooth Fairy leaves. Cross-sectional questionnaire study. Zürich, Switzerland. 3617 parents of children (mean age of children, 6.8 years; 51.9% girls) who had lost at least one deciduous tooth received a self-developed questionnaire; 1274 questionnaires were returned (35.2%). Primary outcome variables were the Tooth Fairy's visit after tooth loss and the amount of money given in case of a visit. Child- and parent-related variables were assessed as predictors of the main outcomes. Most parents (71.0%) reported that the Tooth Fairy visited their child. She usually exchanged the lost tooth for money (55.8% of visits) or placed money next to the tooth (40.7%); rarely did she take the tooth without pecuniary substitution. The Tooth Fairy left an average of 7.20 Swiss francs (approximately AU$9.45). The Tooth Fairy favoured visiting for the teeth of older children (odds ratio [OR], per year, 1.87; 95% CI, 1.09-3.21), of boys (OR, 2.65; 95% CI, 1.09-6.42), and of children who believed in her (OR, 4.12; 95% CI, 1.77-9.64). The amount of money was influenced by maternal, but not paternal socio-demographic factors, including level of education (OR, per level, 0.78; 95% CI, 0.66-0.92) and country of origin (OR, Western countries v non-Western countries, 2.35; 95% CI, 1.20-4.62). The Tooth Fairy does not visit all children after tooth loss, displaying clear preferences in her choice of business partners. The odds of a visit are dramatically increased if she is believed in, and the value of a deciduous tooth is influenced by socio-demographic factors.

  17. affective domain in developing environmental

    African Journals Online (AJOL)

    AN ETHIC FOR GEOGRAPHY: THE ROLE OF THE. AFFECTIVE DOMAIN IN DEVELOPING ENVIRONMENTAL. AWARENESS. Margaret E. Marker. Geography is a subject with integral ethical and moral components. However, because of the subject's traditionally close association with scientific rationality this factor has not ...

  18. Tooth Eruption without Roots

    OpenAIRE

    Wang, X.-P.

    2013-01-01

    Root development and tooth eruption are very important topics in dentistry. However, they remain among the less-studied and -understood subjects. Root development accompanies rapid tooth eruption, but roots are required for the movement of teeth into the oral cavity. It has been shown that the dental follicle and bone remodeling are essential for tooth eruption. So far, only limited genes have been associated with root formation and tooth eruption. This may be due to the diffic...

  19. Brief communication: The London atlas of human tooth development and eruption.

    Science.gov (United States)

    AlQahtani, S J; Hector, M P; Liversidge, H M

    2010-07-01

    The aim of this study was to develop a comprehensive evidence-based atlas to estimate age using both tooth development and alveolar eruption for human individuals between 28 weeks in utero and 23 years. This was a cross-sectional, retrospective study of archived material with the sample aged 2 years and older having a uniform age and sex distribution. Developing teeth from 72 prenatal and 104 postnatal skeletal remains of known age-at-death were examined from collections held at the Royal College of Surgeons of England and the Natural History Museum, London, UK (M 91, F 72, unknown sex 13). Data were also collected from dental radiographs of living individuals (M 264, F 264). Median stage for tooth development and eruption for all age categories was used to construct the atlas. Tooth development was determined according to Moorrees et al. (J Dent Res 42 (1963a) 490-502; Am J Phys Anthropol 21 (1963b) 205-213) and eruption was assessed relative to the alveolar bone level. Intraexaminer reproducibility calculated using Kappa on 150 teeth was 0.90 for 15 skeletal remains of age <2 years, and 0.81 from 605 teeth (50 radiographs). Age categories were monthly in the last trimester, 2 weeks perinatally, 3-month intervals during the first year, and at every year thereafter. Results show that tooth formation is least variable in infancy and most variable after the age of 16 years for the development of the third molar. (c) 2010 Wiley-Liss, Inc.

  20. CD 95 mediated apoptosis in embryogenesis: implication in tooth development.

    Czech Academy of Sciences Publication Activity Database

    Matalová, Eva; Šetková, Jana; Blackburn, J.; Míšek, Ivan; Sharpe, P. T.

    2006-01-01

    Roč. 9, 3 (2006), s. 123-128 ISSN 1397-5927 R&D Projects: GA ČR GA304/04/0101; GA MŠk OC B23.001 Institutional research plan: CEZ:AV0Z50450515 Keywords : fas * embryonic development * odontogenesis Subject RIV: EB - Genetics ; Molecular Biology

  1. Multivariate Analysis of Factors Affecting Presence and/or Agenesis of Third Molar Tooth

    Science.gov (United States)

    Alam, Mohammad Khursheed; Hamza, Muhammad Asyraf; Khafiz, Muhammad Aizuddin; Rahman, Shaifulizan Abdul; Shaari, Ramizu; Hassan, Akram

    2014-01-01

    To investigate the presence and/or agenesis of third molar (M3) tooth germs in orthodontics patients in Malaysian Malay and Chinese population and evaluate the relationship between presence and/or agenesis of M3 with different skeletal malocclusion patterns and sagittal maxillomandibular jaw dimensions. Pretreatment records of 300 orthodontic patients (140 males and 160 females, 219 Malaysian Malay and 81 Chinese, average age was 16.27±4.59) were used. Third-molar agenesis was calculated with respect to race, genders, number of missing teeth, jaws, skeletal malocclusion patterns and sagittal maxillomandibular jaw dimensions. The Pearson chi-square test and ANOVA was performed to determine potential differences. Associations between various factors and M3 presence/agenesis groups were assessed using logistic regression analysis. The percentages of subjects with 1 or more M3 agenesis were 30%, 33% and 31% in the Malaysian Malay, Chinese and total population, respectively. Overall prevalence of M3 agenesis in male and female was equal (P>0.05). The frequency of the agenesis of M3s is greater in maxilla as well in the right side (P>0.05). The prevalence of M3 agenesis in those with a Class III and Class II malocclusion was relatively higher in Malaysian Malay and Malaysian Chinese population respectively. Using stepwise regression analyses, significant associations were found between Mx (Pagenesis. This multivariate analysis suggested that Mx and ANB were significantly correlated with the M3 presence/agenesis. PMID:24967595

  2. Multivariate analysis of factors affecting presence and/or agenesis of third molar tooth.

    Directory of Open Access Journals (Sweden)

    Mohammad Khursheed Alam

    Full Text Available To investigate the presence and/or agenesis of third molar (M3 tooth germs in orthodontics patients in Malaysian Malay and Chinese population and evaluate the relationship between presence and/or agenesis of M3 with different skeletal malocclusion patterns and sagittal maxillomandibular jaw dimensions. Pretreatment records of 300 orthodontic patients (140 males and 160 females, 219 Malaysian Malay and 81 Chinese, average age was 16.27±4.59 were used. Third-molar agenesis was calculated with respect to race, genders, number of missing teeth, jaws, skeletal malocclusion patterns and sagittal maxillomandibular jaw dimensions. The Pearson chi-square test and ANOVA was performed to determine potential differences. Associations between various factors and M3 presence/agenesis groups were assessed using logistic regression analysis. The percentages of subjects with 1 or more M3 agenesis were 30%, 33% and 31% in the Malaysian Malay, Chinese and total population, respectively. Overall prevalence of M3 agenesis in male and female was equal (P>0.05. The frequency of the agenesis of M3s is greater in maxilla as well in the right side (P>0.05. The prevalence of M3 agenesis in those with a Class III and Class II malocclusion was relatively higher in Malaysian Malay and Malaysian Chinese population respectively. Using stepwise regression analyses, significant associations were found between Mx (P<0.05 and ANB (P<0.05 and M3 agenesis. This multivariate analysis suggested that Mx and ANB were significantly correlated with the M3 presence/agenesis.

  3. Dental Stem Cell in Tooth Development and Advances of Adult Dental Stem Cell in Regenerative Therapies.

    Science.gov (United States)

    Tan, Jiali; Xu, Xin; Lin, Jiong; Fan, Li; Zheng, Yuting; Kuang, Wei

    2015-01-01

    Stem cell-based therapies are considered as a promising treatment for many clinical usage such as tooth regeneration, bone repairation, spinal cord injury, and so on. However, the ideal stem cell for stem cell-based therapy still remains to be elucidated. In the past decades, several types of stem cells have been isolated from teeth, including dental pulp stem cells (DPSCs), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSCs), dental follicle progenitor stem cells (DFPCs) and stem cells from apical papilla (SCAP), which may be a good source for stem cell-based therapy in certain disease, especially when they origin from neural crest is considered. In this review, the specific characteristics and advantages of the adult dental stem cell population will be summarized and the molecular mechanisms of the differentiation of dental stem cell during tooth development will be also discussed.

  4. Development of dental charts according to tooth development and eruption for Turkish children and young adults

    Energy Technology Data Exchange (ETDEWEB)

    Karadayl, Beytullah; Ozaslan, Abdi [University of Istanbul, Cerrahpasa Faculty of Medicine, Forensic Medicine Department, Istanbul (Turkey); Afsin, Hueseyin [University of Istanbul, Cerrahpasa Faculty of Medicine, Forensic Medicine Department, Istanbul (Turkey); Karadayi, Suekriye [Public Health Agency, Istanbul (Turkey)

    2014-06-15

    In this study, we aimed to develop dental charts for Turkish children and young adults of both genders within the age group of 4.5-22.5 years according to tooth mineralization and eruption in a format similar to that proposed by AlQahtani et al. In total, 753 digital panoramic radiographs from 350 males and 403 females were assessed. The permanent teeth were evaluated according to the classification system described by Demirjian et al. The eruption stage was assessed with Bengston's system, which was modified by AlQahtani et al at four points. Teeth generally developed earlier in females than in males. This was particularly notable in the age group of 5-14 years. However, this difference was usually visible in only one stage, not in all teeth. It has been determined that the mixed dentition period ended with the shedding of the second deciduous molars in both genders. The dental charts presented here included information that could be beneficial to dental clinicians in making appropriate diagnosis and planning orthodontic and surgical procedures. These charts also provided datasets for preliminary dental age estimation in Turkish children and young adults.

  5. Development of dental charts according to tooth development and eruption for Turkish children and young adults

    International Nuclear Information System (INIS)

    Karadayl, Beytullah; Ozaslan, Abdi; Afsin, Hueseyin; Karadayi, Suekriye

    2014-01-01

    In this study, we aimed to develop dental charts for Turkish children and young adults of both genders within the age group of 4.5-22.5 years according to tooth mineralization and eruption in a format similar to that proposed by AlQahtani et al. In total, 753 digital panoramic radiographs from 350 males and 403 females were assessed. The permanent teeth were evaluated according to the classification system described by Demirjian et al. The eruption stage was assessed with Bengston's system, which was modified by AlQahtani et al at four points. Teeth generally developed earlier in females than in males. This was particularly notable in the age group of 5-14 years. However, this difference was usually visible in only one stage, not in all teeth. It has been determined that the mixed dentition period ended with the shedding of the second deciduous molars in both genders. The dental charts presented here included information that could be beneficial to dental clinicians in making appropriate diagnosis and planning orthodontic and surgical procedures. These charts also provided datasets for preliminary dental age estimation in Turkish children and young adults.

  6. Development of dental charts according to tooth development and eruption for Turkish children and young adults.

    Science.gov (United States)

    Karadayı, Beytullah; Afşin, Hüseyin; Ozaslan, Abdi; Karadayı, Sükriye

    2014-06-01

    In this study, we aimed to develop dental charts for Turkish children and young adults of both genders within the age group of 4.5-22.5 years according to tooth mineralization and eruption in a format similar to that proposed by AlQahtani et al. In total, 753 digital panoramic radiographs from 350 males and 403 females were assessed. The permanent teeth were evaluated according to the classification system described by Demirjian et al. The eruption stage was assessed with Bengston's system, which was modified by AlQahtani et al at four points. Teeth generally developed earlier in females than in males. This was particularly notable in the age group of 5-14 years. However, this difference was usually visible in only one stage, not in all teeth. It has been determined that the mixed dentition period ended with the shedding of the second deciduous molars in both genders. The dental charts presented here included information that could be beneficial to dental clinicians in making appropriate diagnosis and planning orthodontic and surgical procedures. These charts also provided datasets for preliminary dental age estimation in Turkish children and young adults.

  7. Use of the natural tooth for soft tissue development: a case series.

    Science.gov (United States)

    Steigmann, Marius; Cooke, Jason; Wang, Homrn-Lay

    2007-12-01

    The achievement of optimal esthetics around anterior dental implants has been a major challenge for many clinicians. The key to an esthetically pleasing appearance lies in the clinician's ability to properly manage the soft tissue profile around dental implants. Hence, the purpose of this case report is to describe a new technique that uses the patient's own natural tooth for the provisional implant restoration to develop soft tissue architecture that is almost identical to the patient's original immediately after tooth extraction. Ten consecutively treated patients were included in this series. Clinical measurements included soft tissue height, papilla appearance, and probing pocket depths. Other parameters such as radiographic bone levels and quality-of-life ratings were also recorded. Results from this study showed that all patients achieved a normal or Class 1 papilla appearance similar to the original appearance of the natural tooth. All patients were very happy with the treatment outcome. This newly suggested approach for restoring an anterior implant can be valuable and esthetically pleasing.

  8. Tooth eruption without roots.

    Science.gov (United States)

    Wang, X-P

    2013-03-01

    Root development and tooth eruption are very important topics in dentistry. However, they remain among the less-studied and -understood subjects. Root development accompanies rapid tooth eruption, but roots are required for the movement of teeth into the oral cavity. It has been shown that the dental follicle and bone remodeling are essential for tooth eruption. So far, only limited genes have been associated with root formation and tooth eruption. This may be due to the difficulties in studying late stages of tooth development and tooth movement and the lack of good model systems. Transgenic mice with eruption problems and short or no roots can be used as a powerful model for further deciphering of the cellular, molecular, and genetic mechanisms underlying root formation and tooth eruption. Better understanding of these processes can provide hints on delivering more efficient dental therapies in the future.

  9. Vascular endothelial growth factor behavior in different stages of tooth germ development.

    Science.gov (United States)

    Mastrangelo, Filiberto; Sberna, Maria T; Vinci, Raffaele; Iaderosa, Giovanni; Tettamanti, Lucia; Cantatore, Giuseppe; Tagliabue, Angelo; Gherlone, Enrico F

    2016-08-01

    Scientific studies show a possible influence of intercellular and intracellular proteins (VEGF) on the development of physiological and pathological tissue. VEGF, a key regulator of angiogenesis, it would seem essential to take action during the embryonic development of the dental germ. The purpose of the study is to investigate the importance of the enzymatic activity of VEGF through protein quantification at different stages of tooth germ development. The quantification of VEGF protein was performed by 3 different laboratory tests: Western-blot analysis, semi-quantitative reverse transcriptase-polymerase chain reaction analysis (RT-PCR) and finally immunohistochemical analysis. Cell cultures of tooth tissue examined are: endothelial cells, stellate reticulum cells, odontoblasts and ameoblast. The VEGF peptide seems to induce an intense cell proliferation, not concomitant with differentiation towards the endothelial line. The expression of VEGF in the inner enamel epithelium (ameloblasts) would seem to depend on the stage of differentiation, leading us to deduce that VEGF and its respective receptor are expressed in dental germ and that induce alterations not only on the vascularization, but also on the inner epithelium activation and then on dental enamel development, respectively on cap and bell stages of embryogenesis. In our survey, the positive expression of VEGF in all the samples examined, might suggest a fundamental role of angiogenic gene proteins during all stages of embryonic tooth development. It is also characteristic the behavior of stellate reticulum cells, with a significant reduction in VEGF action between early and late stage, which could suggest a possible role of stellate reticulum cells, which would be able to promote and maintain an adequate energy supply to the tissues during early and late stages of differentiation and proliferation.

  10. Wnt/beta-catenin signaling plays an essential role in activation of odontogenic mesenchyme during early tooth development

    OpenAIRE

    Chen, Jianquan; Lan, Yu; Baek, Jin-A; Gao, Yang; Jiang, Rulang

    2009-01-01

    Classical tissue recombination studies demonstrated that initiation of tooth development depends on activation of odontogenic potential in the mesenchyme by signals from the presumptive dental epithelium. Although several members of the Wnt family of signaling molecules are expressed in the presumptive dental epithelium at the beginning of tooth initiation, whether Wnt signaling is directly involved in the activation of the odontogenic mesenchyme has not been characterized. In this report, we...

  11. Stages and transitions in the development of tooth brushing skills in children of Mexican immigrant families: a qualitative study.

    Science.gov (United States)

    Benadof, Dafna; Polk, Deborah; Documet, Patricia

    2015-01-01

    Compared with white children, the oral health of Latino children in the United States is much worse. One factor contributing to oral health is tooth brushing. Few studies have addressed the formation of the tooth brushing habit in children, and only one of them studied a Latino population. The purpose of this study is to explore the development of the tooth brushing habit in children of Mexican immigrant families and develop hypothesis based on its results. This is an exploratory qualitative study, with a case study design based on 20 in-depth interviews. Participants were Mexican immigrant mothers living in Pittsburgh and Philadelphia, PA. Participants had at least one child six-years-old or younger. Interviews were recorded, transcribed verbatim, and analyzed using qualitative analysis procedures. Four stages were identified in the tooth brushing learning process: initiation and entirely dependent tooth brushing, assisted tooth brushing, road to tooth brushing independence, and independent tooth brushing. Two factors influenced parents' teaching approaches: parents' perceptions of their child's achievement of physical, cognitive, and motor developmental milestones and parents' knowledge about oral hygiene. We identified four distinct stages and found evidence to hypothesize that transitions from one stage to the next are triggered not by the age of the child but by parents' knowledge about oral hygiene and their perceptions of their child's achievement of physical, cognitive, and motor developmental milestones. Future quantitative research studies should be conducted to test this hypothesis in larger groups of Latinos as well as other ethnic groups. © 2015 American Association of Public Health Dentistry.

  12. Does tooth brushing influence the development and progression of non-inflammatory gingival recession? A systematic review.

    Science.gov (United States)

    Rajapakse, P Sunethra; McCracken, Giles I; Gwynnett, Erika; Steen, Nick D; Guentsch, Arndt; Heasman, Peter A

    2007-12-01

    The aim of this systematic review was to produce the best available evidence and pool appropriate data to evaluate the effect of tooth brushing on the initiation and progression of non-inflammatory gingival recession. A protocol was developed a priori for the question: "Do factors associated with tooth brushing predict the development and progression of non-inflammatory gingival recession in adults?" The search covered six electronic databases between January 1966 and July 2005. Hand searching included searches of the Journal of Clinical Periodontology, Journal of Periodontal Research and the Journal of Periodontology. Bibliographies of narrative reviews, conference proceedings and relevant texts known to the authors were also searched. Inclusion of titles, abstracts and ultimately full texts was based on consensus between three reviewers. The full texts of 29 papers were read and 18 texts were eligible for inclusion. One abstract from EuroPerio 5 reported a randomized-controlled clinical trial [Level I evidence] in which the authors concluded that the toothbrushes significantly reduced recessions on buccal tooth surfaces over 18 months. Of the remaining 17 observational studies, two concluded that there appeared to be no relationship between tooth brushing frequency and gingival recession. Eight studies reported a positive association between tooth brushing frequency and recession. Other potential risk factors were duration of tooth brushing, brushing force, frequency of changing the toothbrush, brush (bristle) hardness and tooth brushing technique. None of the observational studies satisfied all the specified criteria for quality appraisal and a valid appraisal of the quality of the randomized-controlled trial was not possible. The data to support or refute the association between tooth brushing and gingival recession are inconclusive.

  13. Natural selection and molecular evolution in primate PAX9 gene, a major determinant of tooth development.

    Science.gov (United States)

    Pereira, Tiago V; Salzano, Francisco M; Mostowska, Adrianna; Trzeciak, Wieslaw H; Ruiz-Linares, Andrés; Chies, José A B; Saavedra, Carmen; Nagamachi, Cleusa; Hurtado, Ana M; Hill, Kim; Castro-de-Guerra, Dinorah; Silva-Júnior, Wilson A; Bortolini, Maria-Cátira

    2006-04-11

    Large differences in relation to dental size, number, and morphology among and within modern human populations and between modern humans and other primate species have been observed. Molecular studies have demonstrated that tooth development is under strict genetic control, but, the genetic basis of primate tooth variation remains unknown. 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, which mainly involves the posterior teeth. To determine whether this gene is polymorphic in humans, we sequenced approximately 2.1 kb of the entire four-exon region (exons 1, 2, 3 and 4; 1,026 bp) and exon-intron (1.1 kb) boundaries of 86 individuals sampled from Asian, European, and Native American populations. We provided evidence that human PAX9 polymorphisms are limited to exon 3 only and furnished details about the distribution of a mutation there in 350 Polish subjects. To investigate the pattern of selective pressure on exon 3, we sequenced ortholog regions of this exon in four species of New World monkeys and one gorilla. In addition, orthologous sequences of PAX9 available in public databases were also analyzed. Although several differences were identified between humans and other species, our findings support the view that strong purifying selection is acting on PAX9. New World and Old World primate lineages may, however, have different degrees of restriction for changes in this DNA region.

  14. Osteoadherin accumulates in the predentin towards the mineralization front in the developing tooth.

    Directory of Open Access Journals (Sweden)

    Hero Nikdin

    Full Text Available Proteoglycans (PG are known to be involved in the organization and assembly of the extracellular matrix (ECM prior to mineral deposition. Osteoadherin (OSAD, a keratan sulphate PG is a member of the small leucine-rich (SLRP family of PGs and unlike other SLRPs, OSAD expression is restricted to mineralized tissues. It is proposed to have a high affinity for hydroxyapatite and has been shown to be expressed by mature osteoblasts but its exact role remains to be elucidated.We investigated the protein distribution of OSAD in the developing mouse tooth using immunohistochemistry and compared its expression with other SLRPs, biglycan (BGN, decorin (DCN and fibromodulin (FMD. OSAD was found to be specifically localized in the predentin layer of the tooth and focused at the mineralization front. These studies were confirmed at the ultrastructural level using electron microscopy (iEM, where the distribution of immunogold labeled OSAD particles were quantified and significant amounts were found in the predentin, forming a gradient towards the mineralization front. In addition, iEM results revealed OSAD to lie in close association with collagen fibers, further suggesting an important role for OSAD in the organization of the ECM. The expression profile of mineralization-related SLRP genes by rat dental pulp cells exposed to mineralization inducing factors, showed an increase in all SLRP genes. Indeed, OSAD expression was significantly increased during the mineralization process, specifically following, matrix maturation, and finally mineral deposition. Alizarin Red S staining for calcium deposition showed clear bone-like nodules, which support matrix maturation and mineralization.These studies provide new evidence for the role of OSAD in the mineralization process and its specific localization in the predentin layer accumulating at the mineralization front highlighting its role in tooth development.

  15. Homeobox genes and tooth development: Understanding the biological pathways and applications in regenerative dental science.

    Science.gov (United States)

    Ramanathan, Anand; Srijaya, Thekkeparambil Chandrabose; Sukumaran, Prema; Zain, Rosnah Binti; Abu Kasim, Noor Hayaty

    2018-01-01

    Homeobox genes are a group of conserved class of transcription factors that function as key regulators during the embryonic developmental processes. They act as master regulator for developmental genes, which involves coordinated actions of various auto and cross-regulatory mechanisms. In this review, we summarize the expression pattern of homeobox genes in relation to the tooth development and various signaling pathways or molecules contributing to the specific actions of these genes in the regulation of odontogenesis. An electronic search was undertaken using combination of keywords e.g. Homeobox genes, tooth development, dental diseases, stem cells, induced pluripotent stem cells, gene control region was used as search terms in PubMed and Web of Science and relevant full text articles and abstract were retrieved that were written in English. A manual hand search in text books were also carried out. Articles related to homeobox genes in dentistry and tissue engineering and regenerative medicine of odontogenesis were selected. The possible perspective of stem cells technology in odontogenesis and subsequent analysis of gene correction pertaining to dental disorders through the possibility of induced pluripotent stem cells technology is also inferred. We demonstrate the promising role of tissue engineering and regenerative medicine on odontogenesis, which can generate a new ray of hope in the field of dental science. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. New developed cylindrical TM010 mode EPR cavity for X-band in vivo tooth dosimetry.

    Directory of Open Access Journals (Sweden)

    Guo Junwang

    Full Text Available EPR tooth in vivo dosimetry is an attractive approach for initial triage after unexpected nuclear events. An X-band cylindrical TM010 mode resonant cavity was developed for in vivo tooth dosimetry and used in EPR applications for the first time. The cavity had a trapezoidal measuring aperture at the exact position of the cavity's cylindrical wall where strong microwave magnetic field H1 concentrated and weak microwave electric field E1 distributed. Theoretical calculations and simulations were used to design and optimize the cavity parameters. The cavity features were evaluated by measuring DPPH sample, intact incisor samples embed in a gum model and the rhesus monkey teeth. The results showed that the cavity worked at designed frequency and had the ability to make EPR spectroscopy in relative high sensitivity. Sufficient modulation amplitude and microwave power could be applied into the aperture. Radiation induced EPR signal could be observed remarkably from 1 Gy irradiated intact incisor within only 30 seconds, which was among the best in scan time and detection limit. The in vivo spectroscopy was also realized by acquiring the radiation induced EPR signal from teeth of rhesus monkey whose teeth was irradiated by dose of 2 Gy. The results suggested that the cavity was sensitive to meet the demand to assess doses of significant level in short time. This cavity provided a very potential option for the development of X-band in vivo dosimetry.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Prevalence and distribution of tooth wear among Sri Lankan adolescents.

    Science.gov (United States)

    Ratnayake, Nilantha; Ekanayake, Lilani

    2010-01-01

    The aim of the present study was to assess the prevalence, distribution and sociodemographic factors associated with tooth wear among Sri Lankan adolescents. A total of 1200 17-year-olds were selected from government, private and international schools in the Colombo district of Sri Lanka using a two-stage cluster sampling technique. The data were collected using a pretested, validated self-administered questionnaire and by conducting a clinical examination. Tooth wear was recorded using a modified version of Smith and Knight's tooth wear index. The prevalence of tooth wear among Sri Lankan adolescents was found to be 22.4%. In nearly 13.7%, tooth wear was confined to the enamel, whereas 8.7% had wear lesions extending up to the dentine. Occlusal surface was the most frequently affected surface, while the first molar was the most frequently affected tooth. Tooth wear was significantly associated with the type of school attended, father's occupational status and mother's level of education. The present study found that nearly one-fourth of the adolescents were affected by tooth wear. These findings are in agreement with those from developed countries where tooth wear has been shown to be an emerging oral health problem.

  19. Tooth extraction

    Science.gov (United States)

    ... several teeth using the methods above. For an impacted tooth , the surgeon may have to cut a flap ... loosens or damages teeth Tooth injury from trauma Impacted teeth that are causing problems, such as wisdom teeth ( ...

  20. Tooth anatomy

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002214.htm Tooth anatomy To use the sharing features on this page, ... upper jawbone is called the maxilla. Images Tooth anatomy References Chan S, Alessandrini EA. Dental injuries. In: Selbst ...

  1. Charcot-Marie-Tooth disease: The development of a diagnostic platform using next generation sequencing

    DEFF Research Database (Denmark)

    Christensen, Rikke; Væth, Signe; Thorsen, Kasper

    Background: Charcot-Marie-Tooth Disease (CMT) is one of the most common inherited neurological diseases. Today, more than 70 CMT related genes are known to cause inherited neuropathy. The diagnostic strategy in most laboratories is based on Sanger-sequencing of few genes. In our patient cohort......, Sanger sequencing of 4 genes have led to a diagnosis in approximately 30% of the patients. Aims: 1) Development of a targeted NGS platform containing 63 genes that currently are found to be associated with CMT. 2) Analysis of the increased diagnostic yield using this platform to analyze 200 CMT samples...... previously analyzed using Sanger sequencing without identification of a disease causing mutation. Materials and Methods: Libraries for 200 patient samples obtained for CMT diagnostics were prepared using Illumina Truseq and target enrichment using SeqCap EZ Choise Library (Nimblegen). The libraries were...

  2. Cavities/Tooth Decay

    Science.gov (United States)

    ... a process that occurs over time. Here's how tooth decay develops: Plaque forms. Dental plaque is a clear sticky film that coats ... by a lack of saliva, which helps prevent tooth decay by washing away food and plaque from your teeth. Substances found in saliva also help counter the ...

  3. 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.

  4. Human dental age estimation combining third molar(s) development and tooth morphological age predictors.

    Science.gov (United States)

    Thevissen, P W; Galiti, D; Willems, G

    2012-11-01

    In the subadult age group, third molar development, as well as age-related morphological tooth information can be observed on panoramic radiographs. The aim of present study was to combine, in subadults, panoramic radiographic data based on developmental stages of third molar(s) and morphological measurements from permanent teeth, in order to evaluate its added age-predicting performances. In the age range between 15 and 23 years, 25 gender-specific radiographs were collected within each age category of 1 year. Third molar development was classified and registered according the 10-point staging and scoring technique proposed by Gleiser and Hunt (1955), modified by Köhler (1994). The Kvaal (1995) measuring technique was applied on the indicated teeth from the individuals' left side. Linear regression models with age as response and third molar-scored stages as explanatory variables were developed, and morphological measurements from permanent teeth were added. From the models, determination coefficients (R (2)) and root-mean-square errors (RMSE) were calculated. Maximal-added age information was reported as a 6 % R² increase and a 0.10-year decrease of RMSE. Forensic dental age estimations on panoramic radiographic data in the subadult group (15-23 year) should only be based on third molar development.

  5. Over-expression of thymosin beta 4 promotes abnormal tooth development and stimulation of hair growth.

    Science.gov (United States)

    Cha, Hee-Jae; Philp, Deborah; Lee, Soo-Hyun; Moon, Hye-Sung; Kleinman, Hynda K; Nakamura, Takashi

    2010-01-01

    Thymosin beta 4 has multi-functional roles in cell physiology. It accelerates wound healing, hair growth and angiogenesis, and increases laminin-5 expression in corneal epithelium. Furthermore, thymosin beta 4 stimulates tumor growth and metastasis by induction of cell migration and vascular endothelial growth factor-mediated angiogenesis. Using a construct on the skin-specific keratin-5 promoter, we have developed thymosin beta 4 over-expressing transgenic mice to further study its functional roles. Thymosin beta 4 in adult skin and in embryonic stages of the transgenic mouse was analyzed by both Western blot and immunohistochemistry. The over-expression of thymosin beta 4 was observed especially around hair follicles and in the teeth in the transgenic mice. We examined the phenotype of the thymosin beta 4 over-expressing mice. Hair growth was accelerated. In addition, the transgenic mice had abnormally-shaped white teeth and dull incisors. We found that the expression of laminin-5 was up-regulated in the skin of the transgenic mice. We conclude that thymosin beta 4 has an important physiological role in hair growth and in tooth development.

  6. The use of cone beam computed tomography in the management of dens invaginatus affecting a strategic tooth in a patient affected by hypodontia: a case report.

    Science.gov (United States)

    Durack, C; Patel, S

    2011-05-01

    To report on the use of cone beam computed tomography (CBCT) in the diagnosis and management of dens invaginatus. Chronic apical periodontitis of an invaginated maxillary lateral incisor was diagnosed in a patient suffering from hypodontia and awaiting active orthodontic therapy. Loss of the tooth would have complicated orthodontic treatment. Conventional periapical radiographs provided insufficient information about the nature of the invagination and its relation to the root canal to formulate an appropriate plan for treating the tooth. A small volume CBCT scan of the tooth revealed that the invagination and the root canal were completely separate, non-communicating spaces and that the wall of the invagination acted as an obstruction to the effective chemomechanical debridement of the infected root canal. An innovative method of accessing the infected root canal, based on information from the CBCT images, was adapted to permit its instrumentation, disinfection and filling. • Teeth with dens invaginatus requiring endodontic treatment present diagnostic and technical challenges. • CBCT can provide essential information in the management of dens invaginatus. © 2011 International Endodontic Journal.

  7. [Mechanisms of tooth eruption].

    Science.gov (United States)

    Maltha, J C

    2014-04-01

    Tooth eruption is of the utmost importance for the normal development of the dentition and the face. Since the 1980s, it has been known that the tooth germ itself is not essential for facilitating the processes that make tooth eruption possible. For that reason, recent research on the regulatory mechanisms of tooth eruption has focused mainly on the enamel organ and the dental follicle. Different regulatory mechanisms act on the occlusal and the apical sides of an erupting tooth. On the occlusal side osteoclast differentiation is stimulated. This leads to the development of an eruption canal, a process in which macrophages and matrix metalloproteases also play an important role. On the apical side the most important factors are the transcription factor RUNX2 and the bone morphogenic protein 2. They are responsible for the deposition of trabecular bone in that area. Many regulatory mechanisms which are involved in tooth eruption are also active in other developmental processes. This explains that certain syndromes can also have an effect on the tooth eruption process.

  8. Exclusion of PAX9 and MSX1 mutation in six families affected by tooth agenesis. A genetic study and literature review.

    Science.gov (United States)

    Tallón-Walton, Victoria; Manzanares-Céspedes, Maria-Cristina; Carvalho-Lobato, Patricia; Valdivia-Gandur, Ivan; Arte, Sirpa; Nieminen, Pekka

    2014-05-01

    In the present study, it is describe the phenotypical analysis and the mutational screening, for genes PAX9 and MSX1, of six families affected by severe forms of tooth agenesis associated with other dental anomalies and systemic entities. Six families affected by severe tooth agenesis associated with other dental anomalies and systemic entities were included. Oral exploration, radiological examination, medical antecedents consideration and mutational screening for PAX9 and MSX1 were carried out. No mutations were discovered despite the fact that numerous teeth were missing. An important phenotypical variability was observed within the probands, not being possible to establish a parallelism with the patterns associated to previously described PAX9 and MSX1 mutations. CONCLUSIONS; These results bring us to conclude that probably other genes can determine phenotypical patterns of dental agenesis in the families studied, different than the ones described in the mutations of PAX9 and MSX1. Moreover, epigenetic factors can be involved, as those that can reduce gene dosage and other post-transcriptional modulation agents, causing dental agenesis associated or not with systemic anomalies.

  9. Interaction between fibronectin and β1 integrin is essential for tooth development.

    Directory of Open Access Journals (Sweden)

    Kan Saito

    Full Text Available The dental epithelium and extracellular matrix interact to ensure that cell growth and differentiation lead to the formation of teeth of appropriate size and quality. To determine the role of fibronectin in differentiation of the dental epithelium and tooth formation, we analyzed its expression in developing incisors. Fibronectin mRNA was expressed during the presecretory stage in developing dental epithelium, decreased in the secretory and early maturation stages, and then reappeared during the late maturation stage. The binding of dental epithelial cells derived from postnatal day-1 molars to a fibronectin-coated dish was inhibited by the RGD but not RAD peptide, and by a β1 integrin-neutralizing antibody, suggesting that fibronectin-β1 integrin interactions contribute to dental epithelial-cell binding. Because fibronectin and β1 integrin are highly expressed in the dental mesenchyme, it is difficult to determine precisely how their interactions influence dental epithelial differentiation in vivo. Therefore, we analyzed β1 integrin conditional knockout mice (Intβ1lox-/lox-/K14-Cre and found that they exhibited partial enamel hypoplasia, and delayed eruption of molars and differentiation of ameloblasts, but not of odontoblasts. Furthermore, a cyst-like structure was observed during late ameloblast maturation. Dental epithelial cells from knockout mice did not bind to fibronectin, and induction of ameloblastin expression in these cells by neurotrophic factor-4 was inhibited by treatment with RGD peptide or a fibronectin siRNA, suggesting that the epithelial interaction between fibronectin and β1 integrin is important for ameloblast differentiation and enamel formation.

  10. Environmental Factors Affecting Preschoolers' Motor Development

    Science.gov (United States)

    Venetsanou, Fotini; Kambas, Antonis

    2010-01-01

    The process of development occurs according to the pattern established by the genetic potential and also by the influence of environmental factors. The aim of the present study was to focus on the main environmental factors affecting motor development. The review of the literature revealed that family features, such as socioeconomic status,…

  11. Gait rehabilitation in a patient affected with Charcot-Marie-Tooth disease associated with pyramidal and cerebellar features and blindness.

    Science.gov (United States)

    Vinci, Paolo

    2003-05-01

    Charcot-Marie-Tooth (CMT) disease, an inherited neuropathy characterized by length-dependent degeneration of the motor and sensory nerve fibers with consequent distal muscle atrophy and sensory reduction, can be associated with symptoms and signs of involvement of the central nervous system and/or cranial nerves. We present a patient with relatively severe CMT, cerebellar ataxia, pyramidal involvement, and blindness due to Leber's hereditary optic neuropathy. The patient presented with poor standing and gait, with consequent severe disability. Factors responsible for the patient's functional impairment (plantarflexor failure, footdrop, foot rotation, knee flexor contracture, poor proprioception, cerebellar dysfunction, spastic paraparesis, blindness) were identified and addressed by a rehabilitation management, which included, as a main intervention, ankle stabilization by drop-foot boots instead of ankle-foot orthoses. Improved balance and independent ambulation resulted from rehabilitation.

  12. Development of Improved HDAC6 Inhibitors as Pharmacological Therapy for Axonal Charcot-Marie-Tooth Disease.

    Science.gov (United States)

    Benoy, Veronick; Vanden Berghe, Pieter; Jarpe, Matthew; Van Damme, Philip; Robberecht, Wim; Van Den Bosch, Ludo

    2017-04-01

    Charcot-Marie-Tooth disease (CMT) is the most common inherited peripheral neuropathy, with an estimated prevalence of 1 in 2500. The degeneration of motor and sensory nerve axons leads to motor and sensory symptoms that progress over time and have an important impact on the daily life of these patients. Currently, there is no curative treatment available. Recently, we identified histone deacetylase 6 (HDAC6), which deacetylates α-tubulin, as a potential therapeutic target in axonal CMT (CMT2). Pharmacological inhibition of the deacetylating function of HDAC6 reversed the motor and sensory deficits in a mouse model for mutant "small heat shock protein B1" (HSPB1)-induced CMT2 at the behavioral and electrophysiological level. In order to translate this potential therapeutic strategy into a clinical application, small drug-like molecules that are potent and selective HDAC6 inhibitors are essential. To screen for these, we developed a method that consisted of 3 distinct phases and that was based on the pathological findings in the mutant HSPB1-induced CMT2 mouse model. Three different inhibitors (ACY-738, ACY-775, and ACY-1215) were tested and demonstrated to be both potent and selective HDAC6 inhibitors. Moreover, these inhibitors increased the innervation of the neuromuscular junctions in the gastrocnemius muscle and improved the motor and sensory nerve conduction, confirming that HDAC6 inhibition is a potential therapeutic strategy in CMT2. Furthermore, ACY-1215 is an interesting lead molecule as it is currently tested in clinical trials for cancer. Taken together, these results may speed up the translation of pharmacological inhibition of HDAC6 into a therapy against CMT2.

  13. Hyaluronan in human deciduous tooth germs in the bell stage. Histochemistry and immunohistochemistry

    DEFF Research Database (Denmark)

    Matthiessen, Martin Ebbe; Garbarsch, Charly; Olsen, Birgitte Engelbrecht

    1997-01-01

    Anatomy, development, glycosaminoglycans, hyaluronan, tooth germs, histochemistry, immunocytochemistry......Anatomy, development, glycosaminoglycans, hyaluronan, tooth germs, histochemistry, immunocytochemistry...

  14. The cracked tooth.

    Science.gov (United States)

    Zuckerman, G R

    1998-01-01

    Fractured molars and premolars are very common. Fractures usually result from cracks that develop and slowly extend until the tooth separates into buccal and lingual fragments. Sometimes, as these cracks expand, the patient exhibits symptoms of what is commonly referred to as "cracked tooth syndrome" (CTS). When CTS occurs, an opportunity exists to diagnose and treat these patients, to relieve their discomfort and prevent sequelae that would require more extensive treatment.

  15. The development of submucosal injection of platelet rich plasma for accelerating orthodontic tooth movement and preserving pressure side alveolar bone

    Directory of Open Access Journals (Sweden)

    Eric J. W. Liou

    2016-01-01

    Full Text Available Although the surgical-assisted accelerated orthodontic tooth movement has been proved to be the most effective one currently, its disadvantages are it is a bone surgery, and it causes loss of alveolar bone that undermines the periodontal support of the target teeth. The submucosal injection of platelet rich plasma (PRP is a technique developed for accelerating orthodontic tooth movement by simulating the effects of bone insult without surgery and loss of alveolar bone. We have revealed clinically that submucosal injection of PRP accelerated the mandibular or maxillary alignment 1.7 folds faster in average, and the acceleration was dose-dependent when the PRP fold (platelet count in PRP/platelet count in blood was <12.5. The optimal PRP fold for a more than 2-fold acceleration of orthodontic alignment ranged from 9.5 to 12.5 folds. On the other hand, the injection of PRP on the pressure side of en masse anterior retraction decreased 71–77% of alveolar bone loss, and this was dose-dependent. The pressure side of en masse anterior retraction had no alveolar bone loss when the PRP fold was higher than 11.0. In conclusion, the optimal PRP fold for the best performance in acceleration of orthodontic tooth movement and preservation of the pressure side alveolar bone is 11.0–12.5.

  16. Third molar development: evaluation of nine tooth development registration techniques for age estimations.

    Science.gov (United States)

    Thevissen, Patrick W; Fieuws, Steffen; Willems, Guy

    2013-03-01

    Multiple third molar development registration techniques exist. Therefore the aim of this study was to detect which third molar development registration technique was most promising to use as a tool for subadult age estimation. On a collection of 1199 panoramic radiographs the development of all present third molars was registered following nine different registration techniques [Gleiser, Hunt (GH); Haavikko (HV); Demirjian (DM); Raungpaka (RA); Gustafson, Koch (GK); Harris, Nortje (HN); Kullman (KU); Moorrees (MO); Cameriere (CA)]. Regression models with age as response and the third molar registration as predictor were developed for each registration technique separately. The MO technique disclosed highest R(2) (F 51%, M 45%) and lowest root mean squared error (F 3.42 years; M 3.67 years) values, but differences with other techniques were small in magnitude. The amount of stages utilized in the explored staging techniques slightly influenced the age predictions. © 2013 American Academy of Forensic Sciences.

  17. Transcription Factors Foxi3 and Sox2 in the Regulation of Tooth Development

    OpenAIRE

    Jussila, Maria

    2014-01-01

    Teeth are ectodermal organs, which form from the embryonic epithelium and mesenchyme. Reciprocal interactions between these two tissues, regulated by the conserved signaling pathways, guide tooth morphogenesis. Activity of each signaling pathway is mediated by transcription factors, which activate or repress target genes of the pathway. During morphogenesis, the shape of the dental epithelium undergoes dramatic changes as it proceeds though placode, bud, and cap stages, finally forming the sh...

  18. Policy factors affecting broadband development in Poland

    DEFF Research Database (Denmark)

    Henten, Anders; Windekilde, Iwona Maria

    2014-01-01

    ’s telecommunications market with the European market. The market reflects all the global trends, a gradually growing significance of mobile telecommunications services, broadband Internet access, construction of offers directed towards clients’ needs, and a strong trend towards market consolidation, which...... and discuss broadband access development in Poland and the policy factors influencing this development as well as to examine national strategies used to stimulate service and infrastructure competition in Poland. There are, indeed, many other factors affecting broadband development such as the income level...

  19. Recent developments in affective recommender systems

    Science.gov (United States)

    Katarya, Rahul; Verma, Om Prakash

    2016-11-01

    Recommender systems (RSs) are playing a significant role since 1990s as they provide relevant, personalized information to the users over the internet. Lots of work have been done in information filtering, utilization, and application related to RS. However, an important area recently draws our attention which is affective recommender system. Affective recommender system (ARS) is latest trending area of research, as publication in this domain are few and recently published. ARS is associated with human behaviour, human factors, mood, senses, emotions, facial expressions, body gesture and physiological with human-computer interaction (HCI). Due to this assortment and various interests, more explanation is required, as it is in premature phase and growing as compared to other fields. So we have done literature review (LR) in the affective recommender systems by doing classification, incorporate reputed articles published from the year 2003 to February 2016. We include articles which highlight, analyse, and perform a study on affective recommender systems. This article categorizes, synthesizes, and discusses the research and development in ARS. We have classified and managed ARS papers according to different perspectives: research gaps, nature, algorithm or method adopted, datasets, the platform on executed, types of information and evaluation techniques applied. The researchers and professionals will positively support this survey article for understanding the current position, research in affective recommender systems and will guide future trends, opportunity and research focus in ARS.

  20. Early life factors that affect allergy development.

    Science.gov (United States)

    Reynolds, Lisa A; Finlay, B Brett

    2017-08-01

    The incidence of allergic disease continues to rise in industrialized countries. The rapid increase in the incidence of allergic disease throughout the past half century suggests that recently altered environmental factors are driving allergy development. Accumulating evidence suggests that environmental experiences that occur during the first months of life can influence the risk of allergic sensitization. In this Review, we present the evidence relating to specific early life exposures that affect future allergy development, and discuss how these exposures may promote either tolerance or allergic sensitization.

  1. Dental Age and Tooth Development in Orthodontic Patients with Agenesis of Permanent Teeth.

    Science.gov (United States)

    Badrov, Jozo; Lauc, Tomislav; Nakaš, Enita; Galić, Ivan

    2017-01-01

    Objective . To compare the development of permanent teeth in a group of children with the congenitally missing permanent teeth (CMPT) and corresponding nonaffected group. Methods . The formation stages of all developing permanent teeth were determined on 345 panoramic radiographs (OPTs) by the method of Haavikko (1970), and dental age was calculated. The paired samples t -test was used to compare the differences between dental age (DA) and chronological age (CA) in those with CMPT and those not affected. Spearman test was used to evaluate the correlation between DA-CA and the number of missing teeth. The Wilcoxon signed rank test was used to compare the development of the teeth adjacent to the place of the agenesis with matched pair in corresponding nonaffected group. Results . Dental age was significantly delayed in CMPT children compared to the nonaffected group ( p < 0.001). The mean differences were -0.57 ± 1.20 years and -0.61 ± 1.23 years in males and females, without difference between sexes ( p = 0.763). The number of missing teeth affected the delay only in females ( p = 0.024). Only mesial teeth in females were significantly delayed in development when compared to the nonaffected group ( p = 0.007). Conclusion . Our findings show that the development of the permanent teeth is delayed when compared to the nonaffected group of the same sex and age.

  2. Dental Age and Tooth Development in Orthodontic Patients with Agenesis of Permanent Teeth

    Directory of Open Access Journals (Sweden)

    Jozo Badrov

    2017-01-01

    Full Text Available Objective. To compare the development of permanent teeth in a group of children with the congenitally missing permanent teeth (CMPT and corresponding nonaffected group. Methods. The formation stages of all developing permanent teeth were determined on 345 panoramic radiographs (OPTs by the method of Haavikko (1970, and dental age was calculated. The paired samples t-test was used to compare the differences between dental age (DA and chronological age (CA in those with CMPT and those not affected. Spearman test was used to evaluate the correlation between DA-CA and the number of missing teeth. The Wilcoxon signed rank test was used to compare the development of the teeth adjacent to the place of the agenesis with matched pair in corresponding nonaffected group. Results. Dental age was significantly delayed in CMPT children compared to the nonaffected group (p<0.001. The mean differences were −0.57 ± 1.20 years and −0.61 ± 1.23 years in males and females, without difference between sexes (p=0.763. The number of missing teeth affected the delay only in females (p=0.024. Only mesial teeth in females were significantly delayed in development when compared to the nonaffected group (p=0.007. Conclusion. Our findings show that the development of the permanent teeth is delayed when compared to the nonaffected group of the same sex and age.

  3. Amoxicillin Use during Early Childhood and Fluorosis of Later Developing Tooth Zones

    Science.gov (United States)

    Levy, Steven M.; Warren, John J.; Broffitt, Barbara

    2015-01-01

    Objectives Amoxicillin use has been reported to be associated with developmental defects on enamel surfaces. This analysis assessed the association between amoxicillin use and fluorosis on late-erupting permanent teeth. Methods As part of the Iowa Fluoride Study, subjects were followed from birth to 32 months with questionnaires every 3-4 months to gather information on fluoride intake and amoxicillin use (n=357 subjects for this analysis). Permanent tooth fluorosis on late-erupting zones was assessed by three trained dentists using the Fluorosis Risk Index (FRI) at approximately age 13. A case was defined as fluorosis if a subject had at least two FRI classification II zone scores of 2 or 3. Chi-square tests and logistic regression were used and relative risks and odds ratios were calculated. Results There were 113 cases and 244 controls. In bivariate analyses, amoxicillin use from 20-24 months significantly increased the risk of fluorosis on FRI classification II zones (44.2% vs 30.4%, RR=1.45, 95% CI 1.05-2.04), but other individual time periods did not. Multivariable logistic regression confirmed the increased risk of fluorosis for amoxicillin use from 20-24 months (OR=2.92, 95% CI=1.34-6.40), after controlling for otitis media, breast-feeding, and fluoride intake. Conclusions Amoxicillin use during early childhood could be a risk factor in the etiology of fluorosis on late-erupting permanent tooth zones, but further research is needed. PMID:21972463

  4. Dietary boron does not affect tooth strength, micro-hardness, and density, but affects tooth mineral composition and alveolar bone mineral density in rabbits fed a high-energy diet.

    Science.gov (United States)

    Hakki, Sema S; SiddikMalkoc; Dundar, Niyazi; Kayis, Seyit Ali; Hakki, Erdogan E; Hamurcu, Mehmet; Baspinar, Nuri; Basoglu, Abdullah; Nielsen, Forrest H; Götz, Werner

    2015-01-01

    The objective of this study was to determine whether dietary boron (B) affects the strength, density and mineral composition of teeth and mineral density of alveolar bone in rabbits with apparent obesity induced by a high-energy diet. Sixty female, 8-month-old, New Zealand rabbits were randomly assigned for 7 months into five groups as follows: (1) control 1, fed alfalfa hay only (5.91 MJ/kg and 57.5 mg B/kg); (2) control 2, high energy diet (11.76 MJ and 3.88 mg B/kg); (3) B10, high energy diet + 10 mg B gavage/kg body weight/96 h; (4) B30, high energy diet + 30 mg B gavage/kg body weight/96 h; (5) B50, high energy diet + 50 mg B gavage/kg body weight/96 h. Maxillary incisor teeth of the rabbits were evaluated for compression strength, mineral composition, and micro-hardness. Enamel, dentin, cementum and pulp tissue were examined histologically. Mineral densities of the incisor teeth and surrounding alveolar bone were determined by using micro-CT. When compared to controls, the different boron treatments did not significantly affect compression strength, and micro-hardness of the teeth, although the B content of teeth increased in a dose-dependent manner. Compared to control 1, B50 teeth had decreased phosphorus (P) concentrations. Histological examination revealed that teeth structure (shape and thickness of the enamel, dentin, cementum and pulp) was similar in the B-treated and control rabbits. Micro CT evaluation revealed greater alveolar bone mineral density in B10 and B30 groups than in controls. Alveolar bone density of the B50 group was not different than the controls. Although the B treatments did not affect teeth structure, strength, mineral density and micro-hardness, increasing B intake altered the mineral composition of teeth, and, in moderate amounts, had beneficial effects on surrounding alveolar bone.

  5. [Clinical observation on the characteristics of occlusion and tooth abrasion in patients with cracked tooth].

    Science.gov (United States)

    Chen, Yu; Lin, Zheng-mei; Ling, Jun-qi

    2009-09-01

    To investigate the occlusal characteristics and the condition of tooth abrasion in patients with cracked tooth and to discuss the etiology of the cracked tooth and the relationships between occlusal disorder, tooth abrasion and cracked tooth. Twenty-seven patients with cracked tooth were selected. The occlusal courses were recorded by T-ScanIII system in intercuspal position, protrusive movement and lateral movement. Teeth with cracked tooth were regarded as the cracked tooth group, and the healthy adjacent teeth as the control group. The distribution of premature contact, occlusal interference, the center of occlusal force were examined. The abrasive conditions of the two groups were recorded according to the Smith tooth wear index and compared. There were more teeth with occlusal interference in cracked tooth group (20 teeth) than in the control group (6 teeth), which was significantly different (OR = 5.67, chi(2) = 8.45, P = 0.003). In 24 patients with single affected tooth, the center of occlusal force (COF) located in the inside and outside ellipse were 6 teeth (25%) and 18 teeth (75%) respectively, Z test showed that there were statistical differences between the cracked tooth group and normal people. In cracked tooth group, the proportion of the teeth with abrasion was higher in teeth with occlusal interference than those without occlusal interference (chi(2) = 4.79, P = 0.029). The formation of the cracked tooth was related to the occlusal disorder and associated with the tooth abrasion.

  6. 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.

  7. Tooth wear

    Directory of Open Access Journals (Sweden)

    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

  8. 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.

  9. Physico-mechanical properties determination using microscale homotopic measurements: Application to sound and caries-affected primary tooth dentin

    Science.gov (United States)

    Marangos, Orestes; Misra, Anil; Spencer, Paulette; Bohaty, Brenda; Katz, J. Lawrence

    2009-01-01

    Microscale elastic moduli, composition and density have rarely been determined at the same location for biological materials. In this paper, we have performed homotopic measurements to determine the physico-mechanical properties of a second primary molar specimen exhibiting sound and caries-affected regions. A microscale acoustic impedance map of a section through this sample was acquired using scanning acoustic microscopy (SAM). Scanning electron microscopy was then used to obtain mineral mass fraction of the same section using backscattered images. Careful calibration of each method was performed to reduce system effects and obtain accurate data. Resorption, demineralization and hypermineralization mechanisms were considered in order to derive relationships between measured mineral mass fraction and material mass density. As a result, microscale mass density was determined at the same lateral resolution and location as the SAM data. The mass density and the acoustic impedance were combined to find the microscale elastic modulus and study the relationship between microscale composition and mechanical properties. PMID:19059013

  10. Hardness and elasticity of caries-affected and sound primary tooth dentin bonded with 4-META one-step self-etch adhesives

    Science.gov (United States)

    Hosoya, Yumiko; Tay, Franklin R.; Miyakoshi, Shoichi; Pashley, David H.

    2013-01-01

    Purpose This study evaluated the quality of the interface of sound and carious primary tooth dentin bonded with two 4-META one-step self-etch adhesives. Methods Twelve sound and twelve carious primary molars were bonded with AQ Bond Plus (AQBP; Sun Medical) or Hybrid Bond (HB; Sun Medical) and restored with Clearfil Protect Liner F (Kuraray Medical Inc.). After 24 hours of water immersion, the teeth were sectioned and polished. Resin-dentin interfaces were measured with a nano-indentation tester and hardness and Young’s modulus were calculated. Data were analyzed using one-way or two-ways ANOVA and Fisher’s PLSD test with α=0.05. Resin-dentin interfaces were also observed with SEM and TEM. Ammoniacal silver nitrate was used as a tracer for TEM observation. Results Hardness and Young’s modulus of the interfacial dentin were significantly lower than the underlying intact dentin except for the carious-AQBP group. However, there was no significant difference of hardness and Young's moduli of the interfacial dentin among all groups. TEM revealed extensive interfacial nanoleakage in sound dentin bonded with either AQBP or HB. For the carious teeth, nanoleakage was absent in the hybrid layers bonded with the two adhesives. However, extensive silver deposits were identified from the subsurface, porous caries-affected dentin. PMID:18795517

  11. Influence of self-esteem and negative affectivity on oral health-related quality of life in patients with partial tooth loss.

    Science.gov (United States)

    Özhayat, Esben B

    2013-10-01

    To meaningfully interpret oral health-related quality of life (OHRQoL) measures, the influence of personality traits must be investigated. To investigate and quantify the influence of self-esteem and negative affectivity (NA) on OHRQoL. It was hypothesized that low self-esteem and high NA would be associated with worse OHRQoL. OHRQoL measured by the Oral Health Impact Profile 49 (OHIP-49), self-esteem measured by the Rosenberg Self-Esteem Scale (RSES), NA measured by the Eysenck Personality Inventory Questionnaire (EPI-Q), global oral rating of oral comfort and controlling variables (gender, age, number of teeth, experience of wearing removable dental prostheses (RDP), location of missing teeth and zone of missing teeth) were collected from 81 patients with partial tooth loss, signed in for treatment with RDP. Bivariate analyses showed that the EPI-Q score had the highest correlation with OHIP-49 score (R = 0.5). Both EPI-Q and RSES score had a stronger correlation with psychosocial items than physical/functional items of the OHIP-49. In the multivariate analyses, the controlling variables alone explained 17.75% of the variance in OHIP-49 score, while addition of EPI-Q score, RSES score and both EPI-Q and RSES score explained additionally 11.64%, 6.07% and 14.12%, respectively. For each unit increase in EPI-Q score, the OHIP-49 score increased 5.1 units and for each unit increase in RSES score, the OHIP-49 score decreased 1.1. NA was statistically and clinically significantly higher and self-esteem was statistically significantly lower in patients reporting worse oral comfort. NA had the strongest and most clinically meaningful influence, but both NA and self-esteem was found to influence OHRQoL; low self-esteem and high NA was associated with worse OHRQoL. This indicates the possibility to explain some of the impact of tooth loss on OHRQoL based on personality traits. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Expression of Ki-67, Oct-4, γ-tubulin and α-tubulin in human tooth development.

    Science.gov (United States)

    Kero, Darko; Novakovic, Josip; Vukojevic, Katarina; Petricevic, Josko; Kalibovic Govorko, Danijela; Biocina-Lukenda, Dolores; Saraga-Babic, Mirna

    2014-11-01

    To analyze factors controlling cell proliferation and differentiation, and appearance of primary cilia during the cap and bell stages of incisor or/and canine human enamel organs. Qualitative and quantitative analysis of proliferating Ki-67 positive cells and expression of γ-tubulin, α-tubulin and Oct-4 was immunohistochemically analyzed in the cap an bell stages of 10 developing human incisor and canine germs, 8-21 weeks old. During the analyzed period, ratio of Ki-67 positive cells changed in outer enamel epithelium from 48.86% to 24.52%, in inner enamel epithelium increased from 56.11% to 60.06% and then dropped to 44.24%. While in dental papilla proliferation first increased from 46.26% to 55.45%, and then dropped to 22.08%, a constant decrease of proliferation characterized enamel reticulum (from 46.26% to 15.49%). Strong cytoplasmic Oct-4 expression characterized epithelial parts of enamel organ, particularly the differentiating ameloblasts. During further development, Oct-4 expression shifted to both nuclear and cytoplasmic expression in mesenchymal tooth components. Primary cilia characterized most of the cells in developing enamel organ. While non-ciliated (proliferating) cells mainly contained two centrioles (γ-tubulin), the primary cilia (α-tubulin) were arising from basal bodies (γ-tubulin) of non-proliferating cells. We suggest that increase in cell proliferation enables growth of enamel organ, while its selective decrease leads to disintegration of some tooth parts. Drop of proliferation coincided with initiation of ameloblast and odontoblast differentiation. Additionally, cell differentiation was accompanied by increased expression of Oct-4 and probably by signalling via primary cilia, both regulating processes of cell proliferation and differentiation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Cadmium affects retinogenesis during zebrafish embryonic development

    International Nuclear Information System (INIS)

    Hen Chow, Elly Suk; Yu Hui, Michelle Nga; Cheng, Chi Wa; Cheng, Shuk Han

    2009-01-01

    Ocular malformations are commonly observed in embryos of aquatic species after exposure to toxicants. Using zebrafish embryos as the model organism, we showed that cadmium exposure from sphere stage (4 hpf) to end of segmentation stage (24 hpf) induced microphthalmia in cadmium-treated embryos. Embryos with eye defects were then assessed for visual abilities. Cadmium-exposed embryos were behaviorally blind, showing hyperpigmentation and loss of camouflage response to light. We investigated the cellular basis of the formation of the small eyes phenotype and the induction of blindness by studying retina development and retinotectal projections. Retinal progenitors were found in cadmium-treated embryos albeit in smaller numbers. The number of retinal ganglion cells (RGC), the first class of retinal cells to differentiate during retinogenesis, was reduced, while photoreceptor cells, the last batch of retinal neurons to differentiate, were absent. Cadmium also affected the propagation of neurons in neurogenic waves. The neurons remained in the ventronasal area and failed to spread across the retina. Drastically reduced RGC axons and disrupted optic stalk showed that the optic nerves did not extend from the retina beyond the chiasm into the tectum. Our data suggested that impairment in neuronal differentiation of the retina, disruption in RGC axon formation and absence of cone photoreceptors were the causes of microphthalmia and visual impairment in cadmium-treated embryos

  14. NSAIDs in orthodontic tooth movement

    Directory of Open Access Journals (Sweden)

    Muthukumar Karthi

    2012-01-01

    Full Text Available Orthodontic tooth movement is basically a biological response toward a mechanical force. The movement is induced by prolonged application of controlled mechanical forces, which create pressure and tension zones in the periodontal ligament and alveolar bone, causing remodeling of tooth sockets. Orthodontists often prescribe drugs to manage pain from force application to biologic tissues. Nonsteroidal anti-inflammatory drugs (NSAIDs are the drugs usually prescribed. NSAIDs block prostaglandin synthesis and result in slower tooth movement. Prostaglandins have been found to play a direct role in bone resorption. Aspirin, acetaminophen, ibuprofen, diclofenac, vadecoxib, and celecoxib are the commonly prescribed drugs. Acetaminophen is the drug of choice for orthodontic pain without affecting orthodontic tooth movement.

  15. For the development of therapy with ionising radiation in tooth, mouth and jaw medicine. An historical summary

    International Nuclear Information System (INIS)

    Halbleib, T.

    1983-01-01

    Based on the corresponding literature study, the development of therapy with ionising radiation, especially in the areas of tooth, mouth and jaw medicine, is reported from the discovery of X-rays up till the present. First from 1915 on did the X-ray antiphlogistic irradiation with in importance, from 1925 to about 1940 it played a domineering role, after the war was hardly still in use and since 1970 is considered in the stomatological sector obsolete. In comparison, already in 1905 there were individual successes in tumor therapy using X radiation. After many failures and competition with the method of radium therapy in the following years, a new upswing in X-radiation came starting in around 1930 with the introduction of the Chaoul contact therapy. The high point of this development is the introduction of supervolt therapy starting around 1965. It is the result of comprehensive research in the area of radiation physics. As a result of further developed techniques there were soon combined and competing procedures available, whose results, however, have not been adequately compared and documented. From 1970 on electronic data processing has primarily taken over individual irradiation planning (cobalt 60 and electron irradiation), predictions about clinically relevant therapy successes are not present at this time. (TRV) [de

  16. How Economic Development Affects Antibiotic Resistance

    OpenAIRE

    John B. Horowitz; H. Brian Moehring

    2014-01-01

    Initially, economic development increases resistance because migration of people to urban areas in developing countries increases incomes, crowding and the use of antibiotics. Also, developing countries often don't require prescriptions or distribute high quality antibiotics. In developed countries, antibiotic resistance often falls or there is a decline in the rate of growth of resistance because infections decline with improvements in water quality, sanitation, housing and nutrition. Howeve...

  17. Analysis of split tooth as an unstudied reason for tooth extraction.

    Science.gov (United States)

    Osaghae, Ifueko Patience; Azodo, Clement Chinedu

    2014-09-10

    Split tooth is an unstudied reason for tooth extraction. The purpose of this study was to determine and analyze split tooth as a reason for extraction in a dental clinic in Benin City. The prospective study was carried out on 669 patients having tooth extraction between May, 2005 and December, 2012. Over the period of the study, diagnosis and tooth extraction were done by three dentists of more five years practice experience. The indications for tooth extraction were noted with specific interest on those diagnosed as split tooth without restoration. Data was entered into Microsoft excel, sorted and transported into SPSS (SPSS version 16.0, Chicago, IL, USA). Split teeth constituted for 39 (5%) of extracted teeth. This 39 extractions were done in 38 patients meaning that two split teeth were extracted on separate occasions from same patient. The majority 23 (61%) of extracted split tooth were done in patients in the fifth decade of life. More of the split tooth extraction were performed in males 28 (72%) than females 11 (28%). Overall mandibular teeth were more affected than the maxillary teeth and the most affected teeth were mandibular second molars 23 (59%) while the least affected were the mandibular first premolars 1 (3%) and the third molars 1 (3%). The reported masticatory accident as aetiology, were biting on stone 21 (53%) or piece of bone 10 (26%) while eating. A few 3 (8%) were suspected bruxists. The majority 25 (65%) visited the dental clinic 3-6 months after the incident and onset of symptoms. Split tooth constitute a reasonable common reason for tooth extraction and this was most common in the fifth decade of life. It is therefore important to improve early diagnosis of a cracked tooth in order to prevent the progression of the crack tooth to split tooth.

  18. Regulatory challenges affecting ICT development in Ukraine

    DEFF Research Database (Denmark)

    Kretova, Olga A.

    2017-01-01

    in the region in terms of network readiness (64th place out of 139 economies) and global competitiveness (79th place out of 140 economies) in 2016. The significance of ICT policies is broadly understood at the highest political level in Ukraine, however their implementation has always posed a challenge....... And the chapter is organized as follows. Section 2.1 is the introduction; section 2.2 presents an overview of policies and regulations influencing ICTs in Ukraine; section 2.3 presents a snapshot of the national ICT sector which is dominated by the mobile market and the Broadband Access Technology market; Section...... 2.4 provides an insight into the various ICT regulations, how it affected the markets and the challenges in implementing these policies; section 2.5 highlights the role , successes and challenges of implementing regulations aimed at implementing e-government; and section 2.7 concludes this chapter...

  19. Evolution of high tooth replacement rates in sauropod dinosaurs.

    Science.gov (United States)

    D'Emic, Michael D; Whitlock, John A; Smith, Kathlyn M; Fisher, Daniel C; Wilson, Jeffrey A

    2013-01-01

    Tooth replacement rate can be calculated in extinct animals by counting incremental lines of deposition in tooth dentin. Calculating this rate in several taxa allows for the study of the evolution of tooth replacement rate. Sauropod dinosaurs, the largest terrestrial animals that ever evolved, exhibited a diversity of tooth sizes and shapes, but little is known about their tooth replacement rates. We present tooth replacement rate, formation time, crown volume, total dentition volume, and enamel thickness for two coexisting but distantly related and morphologically disparate sauropod dinosaurs Camarasaurus and Diplodocus. Individual tooth formation time was determined by counting daily incremental lines in dentin. Tooth replacement rate is calculated as the difference between the number of days recorded in successive replacement teeth. Each tooth family in Camarasaurus has a maximum of three replacement teeth, whereas each Diplodocus tooth family has up to five. Tooth formation times are about 1.7 times longer in Camarasaurus than in Diplodocus (315 vs. 185 days). Average tooth replacement rate in Camarasaurus is about one tooth every 62 days versus about one tooth every 35 days in Diplodocus. Despite slower tooth replacement rates in Camarasaurus, the volumetric rate of Camarasaurus tooth replacement is 10 times faster than in Diplodocus because of its substantially greater tooth volumes. A novel method to estimate replacement rate was developed and applied to several other sauropodomorphs that we were not able to thin section. Differences in tooth replacement rate among sauropodomorphs likely reflect disparate feeding strategies and/or food choices, which would have facilitated the coexistence of these gigantic herbivores in one ecosystem. Early neosauropods are characterized by high tooth replacement rates (despite their large tooth size), and derived titanosaurs and diplodocoids independently evolved the highest known tooth replacement rates among archosaurs.

  20. Evolution of high tooth replacement rates in sauropod dinosaurs.

    Directory of Open Access Journals (Sweden)

    Michael D D'Emic

    Full Text Available BACKGROUND: Tooth replacement rate can be calculated in extinct animals by counting incremental lines of deposition in tooth dentin. Calculating this rate in several taxa allows for the study of the evolution of tooth replacement rate. Sauropod dinosaurs, the largest terrestrial animals that ever evolved, exhibited a diversity of tooth sizes and shapes, but little is known about their tooth replacement rates. METHODOLOGY/PRINCIPAL FINDINGS: We present tooth replacement rate, formation time, crown volume, total dentition volume, and enamel thickness for two coexisting but distantly related and morphologically disparate sauropod dinosaurs Camarasaurus and Diplodocus. Individual tooth formation time was determined by counting daily incremental lines in dentin. Tooth replacement rate is calculated as the difference between the number of days recorded in successive replacement teeth. Each tooth family in Camarasaurus has a maximum of three replacement teeth, whereas each Diplodocus tooth family has up to five. Tooth formation times are about 1.7 times longer in Camarasaurus than in Diplodocus (315 vs. 185 days. Average tooth replacement rate in Camarasaurus is about one tooth every 62 days versus about one tooth every 35 days in Diplodocus. Despite slower tooth replacement rates in Camarasaurus, the volumetric rate of Camarasaurus tooth replacement is 10 times faster than in Diplodocus because of its substantially greater tooth volumes. A novel method to estimate replacement rate was developed and applied to several other sauropodomorphs that we were not able to thin section. CONCLUSIONS/SIGNIFICANCE: Differences in tooth replacement rate among sauropodomorphs likely reflect disparate feeding strategies and/or food choices, which would have facilitated the coexistence of these gigantic herbivores in one ecosystem. Early neosauropods are characterized by high tooth replacement rates (despite their large tooth size, and derived titanosaurs and

  1. [Does childhood obesity affect sexual development?].

    Science.gov (United States)

    Wagner, I V; Sergeyev, E; Dittrich, K; Gesing, J; Neef, M; Adler, M; Geserick, M; Pfäffle, R W; Körner, A; Kiess, W

    2013-04-01

    The process of pubertal development is only partly understood and is influenced by many different factors. During the twentieth century there was a general trend toward earlier pubertal development. Fat mass is thought to be a major inducer of puberty. Owing to the rising epidemic of childhood obesity, the relationship between body composition in children and the rate and timing of puberty needs to be investigated. Some studies suggest that central obesity is associated with an earlier onset of pubertal development. Rapid weight gain in early life is linked to advanced puberty in both sexes. A clear correlation exists between increasing body mass index (BMI) and earlier pubertal development in girls. In boys the data are controversial: The majority of studies propose that there is an earlier puberty and voice break in obese boys, but some studies show the opposite. There are several factors and mechanisms that seem to link obesity and puberty, for example, leptin, adipocytokines, and gut peptides. Important players include genetic variation and environmental factors (e.g., endocrine-disrupting chemicals). This article presents the latest studies and evidence on this topic, underlining the inconsistencies in the data and, therefore, the need for further research in this area.

  2. Tooth-bone morphogenesis during postnatal stages of mouse first molar development

    Czech Academy of Sciences Publication Activity Database

    Lungová, V.; Radlanski, R.J.; Tucker, A. S.; Renz, H.; Míšek, Ivan; Matalová, Eva

    2011-01-01

    Roč. 218, č. 6 (2011), s. 699-716 ISSN 0021-8782 R&D Projects: GA ČR GC524/08/J032; GA MZd(CZ) NT11420 Institutional research plan: CEZ:AV0Z50450515 Keywords : apoptosis * dentition * development Subject RIV: EA - Cell Biology Impact factor: 2.370, year: 2011

  3. Molecular Genetics of Supernumerary Tooth Formation

    Science.gov (United States)

    Wang, Xiu-Ping; Fan, Jiabing

    2011-01-01

    Summary Despite advances in the knowledge of tooth morphogenesis and differentiation, relatively little is known about the aetiology and molecular mechanisms underlying supernumerary tooth formation. A small number of supernumerary teeth may be a common developmental dental anomaly, while multiple supernumerary teeth usually have a genetic component and they are sometimes thought to represent a partial third dentition in humans. Mice, which are commonly used for studying tooth development, only exhibit one dentition, with very few mouse models exhibiting supernumerary teeth similar to those in humans. Inactivation of Apc or forced activation of Wnt/β(catenin signalling results in multiple supernumerary tooth formation in both humans and in mice, but the key genes in these pathways are not very clear. Analysis of other model systems with continuous tooth replacement or secondary tooth formation, such as fish, snake, lizard, and ferret, is providing insights into the molecular and cellular mechanisms underlying succesional tooth development, and will assist in the studies on supernumerary tooth formation in humans. This information, together with the advances in stem cell biology and tissue engineering, will pave ways for the tooth regeneration and tooth bioengineering. PMID:21309064

  4. Develop mono-block tooth implants using automate design and FEM analysis

    OpenAIRE

    J.P. Alister; J. Moller,; F. Alister; R. Hunter

    2007-01-01

    Purpose: Purpose of this paper is present a new approach to modelling and design the low cost mono-block dental implants based on the integration of the computer aided techniques. This approach provides the automation of the design process of the mono-block dental implants.Design/methodology/approach: The approach used to develop the modelling and design of the mono-block dental implants are based on the parametrization of the main geometric features of the implants. This approach allows to ...

  5. Management of Developing Anterior Malocclusion due to SupernumeraryTooth with Preventive and Intercep-tive Approach: A 1½ Year Case Study

    Science.gov (United States)

    Kambalimath, HV; Banda, Naveen Reddy

    2010-01-01

    ABSTRACT Variety of clinical complications occurs due to the presence of supernumerary teeth, especially mesiodens. It may result in impaction of one or both central incisors which in turn may lead to a variety of malocclusions. Timely intervention not only prevents malocclusion but also the time taken for corrective orthodontics. A complete case report of developing mesiodens’ tooth germ resulting in malocclusion including treatment in 1½ year period is presented. PMID:27507922

  6. The Effects of Irradiation and Calcium-deficient Diet on the Expression of Bone Morphogenetic Protein-2/4 during Early Tooth Development

    Energy Technology Data Exchange (ETDEWEB)

    Park, Dai Hee; 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 investigate the expression of bone morphogenetic protein (BMP)-2/4 during early tooth development after irradiation and calcium-deficient diet. The pregnant three-week-old Sprague-Dawley rats were used for the study. The control group was non-irradiation/normal diet group (Group 1), and the experimental groups were irradiation/normal diet group (Group 2) and irradiation/calcium-diet group (Group 3). The abdomen of the rats at the 9th day of pregnancy were irradiated with single dose of 350 cGy. The rat pups were sacrificed at embryonic 18 days, 3 days and 14 days after delivery and the maxillae tooth germs were taken. The tissue sections of specimen were stained immunohistochemically with anti-BMP-2/4 antibody. At embryo-18 days, immunoreacivity for BMP-2/4 of the Group 1 was modetate in stratum intermedium of dental organ and weak in dental papilla and dental follicle, but that of Group 2 was weak in cell layer of dental organ, and no immunoreacivity was shown in dental papilla and dental follice of Group 2 and in all tissue components of the Group 3. At postnatal-3 days, immunoreacivity for BMP-2/4 of the Group 1 was strong in cell layer of dental organ, odontoblasts and developing alveolar bone, but that of Group of 2 and Group 3 was weak in odontoblasts and developing alveolar bone. At postnatal-14 days, immunoreacivity for BMP-2/4 of the Group 1 was strong in newly formed cementum, alveolar bone and odontoblasts, but that of Group 2 was weaker than that of Group 1. In the Group 3, tooth forming cell layer showed weak immunoreactivity, but other cell layers showed no immunoreactivity. The expression of bone morphogenetic protein (BMP)-2/4 during early tooth development was disturbed after irradiation and calcium-deficient diet.

  7. Chick tooth induction revisited.

    Science.gov (United States)

    Cai, Jinglei; Cho, Sung-Won; Ishiyama, Mikio; Mikami, Masato; Hosoya, Akihiro; Kozawa, Yukishige; Ohshima, Hayato; Jung, Han-Sung

    2009-07-15

    Teeth have been missing from Aves for almost 100 million years. However, it is believed that the avian oral epithelium retains the molecular signaling required to induce odontogenesis, and this has been widely examined using heterospecific recombinations with mouse dental mesenchyme. It has also been argued that teeth can form from the avian oral epithelium owing to contamination of the mouse mesenchyme with mouse dental epithelial cells. To investigate the possibility of tooth formation from chick oral epithelium and the characteristics of possible chick enamel, we applied LacZ transgenic mice during heterospecific recombination and examined the further tooth formation. Transmission electron microscopy was used to identify the two tissues during development after heterospecific recombination. No mixing was detected between chick oral epithelium and mouse dental mesenchyme after 2 days, and secretory ameloblasts with Tomes' processes were observed after 1 week. Teeth were formed after 3 weeks with a single cusp pattern, possibly determined by epithelial factors, which is similar to that of the avian tooth in the late Jurassic period. These recombinant teeth were smaller than mouse molars, whereas perfect structures of both ameloblasts and enamel showed histological characteristics similar to those of mice. Together these observations consistent with previous report that odontogenesis is initially directed by species-specific mesenchymal signals interplaying with common epithelial signals. (c) 2009 Wiley-Liss, Inc.

  8. Anomalies of tooth formation in hypohidrotic ectodermal dysplasia

    DEFF Research Database (Denmark)

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

    2007-01-01

    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...

  9. Polystyrene nanoparticles affect Xenopus laevis development

    Energy Technology Data Exchange (ETDEWEB)

    Tussellino, Margherita; Ronca, Raffaele [University of Naples Federico II, Department of Biology (Italy); Formiggini, Fabio [Italian Institute of Technology, Center for Advanced Biomaterials for Health Care IIT@CRIB (Italy); Marco, Nadia De [University of Naples Federico II, Department of Biology (Italy); Fusco, Sabato; Netti, Paolo Antonio [Italian Institute of Technology, Center for Advanced Biomaterials for Health Care IIT@CRIB (Italy); Carotenuto, Rosa, E-mail: rosa.carotenuto@unina.it [University of Naples Federico II, Department of Biology (Italy)

    2015-02-15

    Exposing living organisms to nanoparticulates is potentially hazardous, in particular when it takes place during embryogenesis. In this investigation, we have studied the effects of 50-nm-uncoated polystyrene nanoparticles (PSNPs) as a model to investigate the suitability of their possible future employments. We have used the standardized Frog Embryo Teratogenesis Assay-Xenopus test during the early stages of larval development of Xenopus laevis, and we have employed either contact exposure or microinjections. We found that the embryos mortality rate is dose dependent and that the survived embryos showed high percentage of malformations. They display disorders in pigmentation distribution, malformations of the head, gut and tail, edema in the anterior ventral region, and a shorter body length compared with sibling untreated embryos. Moreover, these embryos grow more slowly than the untreated embryos. Expressions of the mesoderm markers, bra (T-box Brachyury gene), myod1 (myogenic differentiation1), and of neural crest marker sox9 (sex SRY (determining region Y-box 9) transcription factor sox9), are modified. Confocal microscopy showed that the nanoparticles are localized in the cytoplasm, in the nucleus, and in the periphery of the digestive gut cells. Our data suggest that PSNPs are toxic and show a potential teratogenic effect for Xenopus larvae. We hypothesize that these effects may be due either to the amount of NPs that penetrate into the cells and/or to the “corona” effect caused by the interaction of PSNPs with cytoplasm components. The three endpoints of our study, i.e., mortality, malformations, and growth inhibition, suggest that the tests we used may be a powerful and flexible bioassay in evaluating pollutants in aquatic embryos.

  10. The circumplex model of affect: an integrative approach to affective neuroscience, cognitive development, and psychopathology.

    Science.gov (United States)

    Posner, Jonathan; Russell, James A; Peterson, Bradley S

    2005-01-01

    The circumplex model of affect proposes that all affective states arise from cognitive interpretations of core neural sensations that are the product of two independent neurophysiological systems. This model stands in contrast to theories of basic emotions, which posit that a discrete and independent neural system subserves every emotion. We propose that basic emotion theories no longer explain adequately the vast number of empirical observations from studies in affective neuroscience, and we suggest that a conceptual shift is needed in the empirical approaches taken to the study of emotion and affective psychopathologies. The circumplex model of affect is more consistent with many recent findings from behavioral, cognitive neuroscience, neuroimaging, and developmental studies of affect. Moreover, the model offers new theoretical and empirical approaches to studying the development of affective disorders as well as the genetic and cognitive underpinnings of affective processing within the central nervous system.

  11. Auditory function in children with Charcot-Marie-Tooth disease.

    Science.gov (United States)

    Rance, Gary; Ryan, Monique M; Bayliss, Kristen; Gill, Kathryn; O'Sullivan, Caitlin; Whitechurch, Marny

    2012-05-01

    The peripheral manifestations of the inherited neuropathies are increasingly well characterized, but their effects upon cranial nerve function are not well understood. Hearing loss is recognized in a minority of children with this condition, but has not previously been systemically studied. A clear understanding of the prevalence and degree of auditory difficulties in this population is important as hearing impairment can impact upon speech/language development, social interaction ability and educational progress. The aim of this study was to investigate auditory pathway function, speech perception ability and everyday listening and communication in a group of school-aged children with inherited neuropathies. Twenty-six children with Charcot-Marie-Tooth disease confirmed by genetic testing and physical examination participated. Eighteen had demyelinating neuropathies (Charcot-Marie-Tooth type 1) and eight had the axonal form (Charcot-Marie-Tooth type 2). While each subject had normal or near-normal sound detection, individuals in both disease groups showed electrophysiological evidence of auditory neuropathy with delayed or low amplitude auditory brainstem responses. Auditory perception was also affected, with >60% of subjects with Charcot-Marie-Tooth type 1 and >85% of Charcot-Marie-Tooth type 2 suffering impaired processing of auditory temporal (timing) cues and/or abnormal speech understanding in everyday listening conditions.

  12. Pediatric Charcot-Marie-Tooth disease.

    Science.gov (United States)

    Jani-Acsadi, Agnes; Ounpuu, Sylvia; Pierz, Kristan; Acsadi, Gyula

    2015-06-01

    Heritable diseases of the peripheral nerves (Charcot-Marie-Tooth disease [CMT]) affect the motor units and sensory nerves, and they are among the most prevalent genetic conditions in the pediatric patient population. The typical clinical presentation includes distal muscle weakness and atrophy, but the severity and progression are largely variable. Improvements in supportive treatment have led to better preservation of patients' motor functions. More than 80 genes have been associated with CMT. These genetic discoveries, along with the developments of cellular and transgenic disease models, have allowed clinicians to better understand the disease mechanisms, which should lead to more specific treatments. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. How Do Age and Tooth Loss Affect Oral Health Impacts and Quality of Life?A Study Comparing Two State Samples of Gujarat and Rajasthan

    Directory of Open Access Journals (Sweden)

    A. Mathur

    2012-01-01

    Full Text Available Objective: Age and tooth loss are expected to have a complex relationship with oral health-related quality of life. So the purpose of this study was to explain the impact of age and tooth loss on oral health-related quality of life using the short form 14-item oral health impact profile (OHIP-14 among two population samples of Gujarat and Rajasthan.Materials and Methods: A cross-sectional questionnaire-based survey was conducted among 1441 subjects collected from two major cities of Gujarat and Rajasthan. Both questionnaire approaches using OHIP-14 scale and clinical examination were conducted in accordance with WHO criteria using type III procedure on the same day. Chi square test, ANOVA and stepwise multiple regression analysis were applied using SPSS software version 15.0.Results: With the increase of age, OHIP mean score in both states increased, but that among Rajasthan state was higher, depicting poor oral health. Whereas, in the remaining 23-27 number of teeth both states showed higher OHIP mean, however again the score was much higher among Rajasthan subjects showing worse oral hygiene. Hence, overall all mean OHIP score for Gujarat was lower indicating good oral health; whereas, that among Rajasthan was higher indicating poor oral health-related quality of life.Conclusion: Both age and tooth loss are associated with each other, but they have an independent effect on the oral health-related quality of life. Thus, all studied populations with complete natural dentition showed good oral health-related quality of life.

  14. Overview of Tooth Disorders

    Science.gov (United States)

    ... necessitated by crowns and bridges. Bonding involves the attachment of tooth-colored fillings to natural teeth with ... Drugs Mentioned In This Article Generic Name Select Brand Names tetracycline ACHROMYCIN V Tooth Disorders Overview of ...

  15. Tooth - abnormal colors

    Science.gov (United States)

    ... 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- ...

  16. Distribution of Cathepsin K in Late Stage of Tooth Germ Development and Its Function in Degrading Enamel Matrix Proteins in Mouse.

    Science.gov (United States)

    Jiang, Tao; Liu, Fen; Wang, Wei-Guang; Jiang, Xin; Wen, Xuan; Hu, Kai-Jin; Xue, Yang

    2017-01-01

    Cathepsin K (CTSK) is a member of cysteine proteinase family, and is predominantly expressed in osteoclastsfor degradationof bone matrix proteins. Given the similarity in physical properties of bone and dental mineralized tissues, including enamel, dentin and cementum, CTSK is likely to take part in mineralization process during odontogenesis. On the other hand, patients with pycnodysostosis caused by mutations of the CTSK gene displayedmultipledental abnormalities, such as hypoplasia of the enamel, obliterated pulp chambers, hypercementosis and periodontal disease. Thereforeitis necessary to study the metabolic role of CTSK in tooth matrix proteins. In this study, BALB/c mice at embryonic day 18 (E18), post-natal day 1 (P1), P5, P10 and P20 were used (5 mice at each time point)for systematic analyses of CTSK expression in the late stage of tooth germ development. We found that CTSK was abundantly expressed in the ameloblasts during secretory and maturation stages (P5 and P10) by immunohistochemistry stainings.During dentinogenesis, the staining was also intense in the mineralization stage (P5 and P10),but not detectable in the early stage of dentin formation (P1) and after tooth eruption (P20).Furthermore, through zymography and digestion test in vitro, CTSK was proved to be capable of hydrolyzing Emdogain and also cleaving Amelogenininto multiple products. Our resultsshed lights on revealing new functions of CTSK and pathogenesis of pycnodysostosis in oral tissues.

  17. Distribution of Cathepsin K in Late Stage of Tooth Germ Development and Its Function in Degrading Enamel Matrix Proteins in Mouse.

    Directory of Open Access Journals (Sweden)

    Tao Jiang

    Full Text Available Cathepsin K (CTSK is a member of cysteine proteinase family, and is predominantly expressed in osteoclastsfor degradationof bone matrix proteins. Given the similarity in physical properties of bone and dental mineralized tissues, including enamel, dentin and cementum, CTSK is likely to take part in mineralization process during odontogenesis. On the other hand, patients with pycnodysostosis caused by mutations of the CTSK gene displayedmultipledental abnormalities, such as hypoplasia of the enamel, obliterated pulp chambers, hypercementosis and periodontal disease. Thereforeitis necessary to study the metabolic role of CTSK in tooth matrix proteins. In this study, BALB/c mice at embryonic day 18 (E18, post-natal day 1 (P1, P5, P10 and P20 were used (5 mice at each time pointfor systematic analyses of CTSK expression in the late stage of tooth germ development. We found that CTSK was abundantly expressed in the ameloblasts during secretory and maturation stages (P5 and P10 by immunohistochemistry stainings.During dentinogenesis, the staining was also intense in the mineralization stage (P5 and P10,but not detectable in the early stage of dentin formation (P1 and after tooth eruption (P20.Furthermore, through zymography and digestion test in vitro, CTSK was proved to be capable of hydrolyzing Emdogain and also cleaving Amelogenininto multiple products. Our resultsshed lights on revealing new functions of CTSK and pathogenesis of pycnodysostosis in oral tissues.

  18. Supplemental tooth in primary dentition

    OpenAIRE

    Mohan, Ravi Prakash Sasankoti; Verma, Sankalp; Singh, Udita; Agarwal, Neha

    2014-01-01

    An extra tooth causing numerical excess in dentition is described as supernumerary tooth, and the resultant condition is termed as hyperdontia. Hyperdontia is more commonly seen in the permanent dentition than primary one. Supernumerary tooth which resembles tooth shape and supplements for occlusion is called as supplemental tooth. We present a case with supplemental tooth in primary dentition.

  19. Supplemental tooth in primary dentition.

    Science.gov (United States)

    Mohan, Ravi Prakash Sasankoti; Verma, Sankalp; Singh, Udita; Agarwal, Neha

    2014-06-09

    An extra tooth causing numerical excess in dentition is described as supernumerary tooth, and the resultant condition is termed as hyperdontia. Hyperdontia is more commonly seen in the permanent dentition than primary one. Supernumerary tooth which resembles tooth shape and supplements for occlusion is called as supplemental tooth. We present a case with supplemental tooth in primary dentition. 2014 BMJ Publishing Group Ltd.

  20. Comparison of the tooth brushing habits of primary school age children and their parents.

    Science.gov (United States)

    Ozbek, Ceren Damla; Eser, Didem; Bektas-Kayhan, Kivanc; Unur, Meral

    2015-01-01

    As they grow, children develop their attitude and behavior related to tooth brushing by taking their parents' oral-dental health behavior as an example. The purpose of this study was to assess whether there was a similarity in tooth brushing between primary school-age children and their parents presenting to the Department of Oral, Dental and Jaw Diseases and Surgery and the Department of Pedodontics, School of Dental Medicine, Istanbul University. The study included 126 children and their parents, as totally 252 subjects. The data on oral hygiene of the subjects were obtained using a questionnaire form including questions on the qualitative-quantitative tooth brushing habits of the children and their parents and the socio-demographic characteristics of their families. In most of the cases, there was a similarity between children and their parents in terms of the frequency of dentist visits, the therapy they underwent in their last dentist visit, the cause of caries, the frequency of tooth brushing, the material used for oral hygiene, the duration of tooth brushing, method of tooth brushing, and tooth sites most brushed, which showed a significant association between children and their parents (p<0.01). Correct knowledge given to the children by their families will positively affect the oral-dental health of the children. Thus, firstly, correct knowledge should be given to the parents so that they can successfully carry out their responsibility in being the correct model for their children in oral-dental health.

  1. Affective design identification on the development of batik convection product

    Science.gov (United States)

    Prastawa, H.; Purwaningsih, R.

    2017-11-01

    The affective design is increasingly applied to product development in order to meet the desires and preferences of customers. Batik is a traditional Indonesian culture containing historical and cultural values. The development of batik design is one of the efforts to strengthen the identity and superiority of Indonesia’s creative industries as well as to preserve batik as the cultural heritage of the nation. Batik product designs offered by the manufacturers do not necessarily correspond with the wishes of consumers, especially the affective values involved. Therefore it is necessary to identify consumer perceptions of convection- based batik product in the form of clothing and fabrics, especially the affective value as the consideration for the designer or manufacturer to develop design alternatives to batik convection products. This research aims to obtain information on consumer affective value, to identify the affective value perception differences among X and Y Generation and to classify affective value in the corresponding cluster of the batik products convection. This study uses Kansei engineering to determine the perception of affective design in the form of Kansei word. Cluster Analysis was used to form clusters that classify affective value of the same class. The results showed that there were 16 pairs of Kansei word which was worth as an affective consumer desire, the 3 indicators that had significant differences among X and Y Generation and 4 clusters with different characteristics.

  2. A Costa Rican family affected with Charcot-Marie-Tooth disease due to the myelin protein zero (MPZ p.Thr124Met mutation shares the Belgian haplotype

    Directory of Open Access Journals (Sweden)

    Alejandro Leal

    2014-12-01

    Full Text Available The p.Thr124Met mutation in the myelin protein zero (MPZ causes the Charcot-Marie-Tooth disease type 2J, a peripheral neuropathy with additional symptoms as pupillary alterations and deafness. It was observed in several families around the world originating e. g. from Germany, Belgium, Japan, Italy and North America. Here we report Central American patients originating from a family in Costa Rica carrying this mutation. Clinical, electrophysiological and molecular analysis of patients and controls were performed, including gene and linked markers´ sequencing. Carriers share almost the entire haplotype with two non related Belgian CMT patients. As a result of the haplotype analysis, based on ten markers (seven SNPs, two microsatellites and an intronic polyA stretch, the founder effect hypothesis for this allele migration is suggestive. Rev. Biol. Trop. 62 (4: 1285-1293. Epub 2014 December 01.

  3. Whole Tooth Regeneration as a Future Dental Treatment.

    Science.gov (United States)

    Oshima, Masamitsu; Tsuji, Takashi

    2015-01-01

    Dental problems caused by dental caries, periodontal disease and tooth injury compromise the oral and general health issues. Current advances for the development of regenerative therapy have been influenced by our understanding of embryonic development, stem cell biology, and tissue engineering technology. Tooth regenerative therapy for tooth tissue repair and whole tooth replacement is currently expected a novel therapeutic concept with the full recovery of tooth physiological functions. Dental stem cells and cell-activating cytokines are thought to be candidate approach for tooth tissue regeneration because they have the potential to differentiate into tooth tissues in vitro and in vivo. Whole tooth replacement therapy is considered to be an attractive concept for next generation regenerative therapy as a form of bioengineered organ replacement. For realization of whole tooth regeneration, we have developed a novel three-dimensional cell manipulation method designated the "organ germ method". This method involves compartmentalisation of epithelial and mesenchymal cells at a high cell density to mimic multicellular assembly conditions and epithelial-mesenchymal interactions in organogenesis. The bioengineered tooth germ generates a structurally correct tooth in vitro, and erupted successfully with correct tooth structure when transplanted into the oral cavity. We have ectopically generated a bioengineered tooth unit composed of a mature tooth, periodontal ligament and alveolar bone, and that tooth unit was engrafted into an adult jawbone through bone integration. Bioengineered teeth were also able to perform physiological tooth functions such as mastication, periodontal ligament function and response to noxious stimuli. In this review, we describe recent findings and technologies underpinning whole tooth regenerative therapy.

  4. Adhesion of resin-modified glass-ionomer cements may affect the integrity of tooth structure in the open sandwich technique.

    Science.gov (United States)

    Czarnecka, Beata; Kruszelnicki, Anna; Kao, Anthony; Strykowska, Marta; Nicholson, John W

    2014-12-01

    To study the interfaces between model cavities prepared in teeth and four glass ionomer cements (two conventional and two resin-modified). Ten non-cavitated molars and premolars were used and, in each, two 3mm deep slot preparations were created on opposing sides of the tooth. The teeth were conditioned as appropriate, then restored using the open sandwich technique, using a conventional glass ionomer (Fuji IX, Ketac Molar) or resin modified glass ionomer (Fuji II LC or N100), followed by completion with composite resin. The teeth were then embedded in a transparent acrylic resin and cut parallel to the long axis through both restorations, using a low speed diamond wheel saw. Samples were evaluated using a metallographic light microscope (100×). Three areas were assessed: the axial wall, the axial gingival line angle and the cavo-surface line angle. Bonding was categorized as inadequate or adequate based on the appearance and inadequate bonding was further studied and classified. Data were analysed statistically using the McNamara analysis. The majority of materials failed to make adequate contact with the axial wall, and there were also flaws at the axial/gingival line angle in several samples. By contrast, the cavo-surface line angle was generally soundly filled and the materials showed intimate contact with the tooth surface in this region. The most serious inadequacy, though, was not lack of intimate contact and/or adhesive bond, but the presence of perpendicular cracks in 30% of the Fuji II LC samples which extended into the underlying dentin. The problems of placement and dentin cracking experienced with these materials demonstrate that adhesive bond strength alone cannot be used as the criterion of success for restorative materials. In fact good adhesion can, in certain cases, promote cracking of the dentin due to stresses within the material, an outcome which is undesirable. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All

  5. A possible etiology for the dilaceration and flexion of permanent tooth roots relative to bone remodeling gradients in alveolar bone

    Directory of Open Access Journals (Sweden)

    Richard G Standerwick

    2014-01-01

    Full Text Available Introduction: Trauma, altered tooth germ position and delayed tooth eruption have been hypothesized as possible causes of tooth root dilacerations and flexion, however these anatomical variations appear more commonly associated with posterior teeth and absence of traumatic history. The Hypothesis: Postulated is that tooth root dilaceration or flexion may be a result of tooth root sheath displacement due to gradients of bone remodeling present within alveolar bone. Evaluation of the Hypothesis: Alveolar bone displays bone remodeling gradients between coronal, apical and basal sections which affect bone plasticity. As a tooth is erupting or experiences delayed eruption, there are other relative dento-skeletal alterations occurring, such as the mesial drift of the dentition and transverse growth of the maxilla. It is plausible that during the physiologic and growth related alteration of the alveolar and basal bones, portions of developing tooth could be found within one or more of the plasticity zones, contributing to alteration of the root sheath and tooth root dilaceration.

  6. Tooth Retained Implant: No More an Oxymoron

    Directory of Open Access Journals (Sweden)

    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.

  7. 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

  8. How to Prevent Tooth Decay in Your Baby

    Science.gov (United States)

    ... also be called nursing caries or baby bottle tooth decay . Healthy dental habits should begin early because tooth decay can ... a pacifier in the parent's or caregiver's mouth. Tooth decay also develops when the child's teeth and gums are exposed to any liquid or ...

  9. Factors Affecting Green Residential Building Development: Social Network Analysis

    Directory of Open Access Journals (Sweden)

    Xiaodong Yang

    2018-05-01

    Full Text Available Green residential buildings (GRBs are one of the effective practices of energy saving and emission reduction in the construction industry. However, many real estate developers in China are less willing to develop GRBs, because of the factors affecting green residential building development (GRBD. In order to promote the sustainable development of GRBs in China, this paper, based on the perspective of real estate developers, identifies the influential and critical factors affecting GRBD, using the method of social network analysis (SNA. Firstly, 14 factors affecting GRBD are determined from 64 preliminary factors of three main elements, and the framework is established. Secondly, the relationships between the 14 factors are analyzed by SNA. Finally, four critical factors for GRBD, which are on the local economy development level, development strategy and innovation orientation, developer’s acknowledgement and positioning for GRBD, and experience and ability for GRBD, are identified by the social network centrality test. The findings illustrate the key issues that affect the development of GRBs, and provide references for policy making by the government and strategy formulation by real estate developers.

  10. 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.

  11. Regenerative Applications Using Tooth Derived Stem Cells in Other Than Tooth Regeneration: A Literature Review

    Directory of Open Access Journals (Sweden)

    Yun-Jong Park

    2016-01-01

    Full Text Available Tooth derived stem cells or dental stem cells are categorized according to the location from which they are isolated and represent a promising source of cells for regenerative medicine. Originally, as one kind of mesenchymal stem cells, they are considered an alternative of bone marrow stromal cells. They share many commonalties but maintain differences. Considering their original function in development and the homeostasis of tooth structures, many applications of these cells in dentistry have aimed at tooth structure regeneration; however, the application in other than tooth structures has been attempted extensively. The availability from discarded or removed teeth can be an innate benefit as a source of autologous cells. Their origin from the neural crest results in exploitation of neurological and numerous other applications. This review briefly highlights current and future perspectives of the regenerative applications of tooth derived stem cells in areas beyond tooth regeneration.

  12. Regenerative Applications Using Tooth Derived Stem Cells in Other Than Tooth Regeneration: A Literature Review.

    Science.gov (United States)

    Park, Yun-Jong; Cha, Seunghee; Park, Young-Seok

    2016-01-01

    Tooth derived stem cells or dental stem cells are categorized according to the location from which they are isolated and represent a promising source of cells for regenerative medicine. Originally, as one kind of mesenchymal stem cells, they are considered an alternative of bone marrow stromal cells. They share many commonalties but maintain differences. Considering their original function in development and the homeostasis of tooth structures, many applications of these cells in dentistry have aimed at tooth structure regeneration; however, the application in other than tooth structures has been attempted extensively. The availability from discarded or removed teeth can be an innate benefit as a source of autologous cells. Their origin from the neural crest results in exploitation of neurological and numerous other applications. This review briefly highlights current and future perspectives of the regenerative applications of tooth derived stem cells in areas beyond tooth regeneration.

  13. Accelerated orthodontic tooth movement: molecular mechanisms.

    Science.gov (United States)

    Huang, Hechang; Williams, Ray C; Kyrkanides, Stephanos

    2014-11-01

    Accelerating orthodontic tooth movement can significantly reduce treatment duration and risks of side effects. The rate of orthodontic tooth movement is chiefly determined by the remodeling of tissues surrounding the roots; this in turn is under the control of molecular mechanisms regulating cellular behaviors in the alveolar bone and periodontal ligament. This review summarizes the current knowledge on the molecular mechanisms underlying accelerated orthodontic tooth movement, and the clinical and experimental methods that accelerate orthodontic tooth movement with possible molecular mechanisms. The review also shows directions for future studies to develop more clinically applicable methods to accelerate orthodontic tooth movement. Copyright © 2014 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  14. Orthodontic Tooth Movement: A Historic Prospective.

    Science.gov (United States)

    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.

  15. Spectroscopic investigations of carious tooth decay.

    Science.gov (United States)

    Thareja, R K; Sharma, A K; Shukla, Shobha

    2008-11-01

    We report on the elemental composition of healthy and infected part of human tooth using laser induced breakdown spectroscopy (LIBS). We have used prominent constituent transitions in laser-excited tooth to diagnose the state of the tooth. A nanosecond laser pulse (355nm, 5ns) was used as an ablating pulse and the sodium (3s2S-3p2P) at 588.99 and (3s2S-3p2P) at 589.99nm, strontium (5s21S-1s5P) at 460.55nm, and calcium (3d3D-4f 3F0) at 452.55nm transitions for spectroscopic analysis. The spectroscopic observations in conjunction with discriminate analysis showed that calcium attached to the hydroxyapatite structure of the tooth was affected severely at the infected part of the tooth. The position-time plots generated from two-dimensional (2D) images conclusively showed a decrease in calcium concentration in the infected region of the irradiated tooth. Using the technique, we could distinguish between the healthy and carious parts of the tooth with significant accuracy.

  16. Stem cells for tooth engineering

    Directory of Open Access Journals (Sweden)

    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.

  17. 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.

  18. 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.

  19. Developing Affective Mental Imagery Stimuli with Multidimensional Scaling

    Directory of Open Access Journals (Sweden)

    Matthew J. Facciani

    2015-06-01

    Full Text Available The goal of this paper is to provide an example of how multidimensional scaling (MDS can be used for stimuli development. The study described in this paper illustrates this process by developing affective mental imagery stimuli using the circumplex model of affect as a guide. The circumplex model of affect argues that all emotions can be described in terms of two underlying primary dimensions: valence and arousal (Russel, 1980. We used MDS to determine if affective mental imagery stimuli obtained from verbal prompts could be separated by arousal and valence to create four distinct categories (high –positive, low-positive, high-negative, and low-negative as seen in other stimuli. 60 students from the University of South Carolina participated in the first experiment to evaluate three sets of stimuli. After being analyzed using MDS, selected stimuli were then assessed again in a second experiment to validate their robust valence and arousal distinctions. The second experiment was conducted with 34 subjects to validate 40 of the best stimuli from experiment 1. It was found that mental imagery stimuli can produce a reliable affective response for the dimensions of valence and arousal and that MDS can be an effective tool for stimuli development.

  20. First permanent molar root development arrest associated with compound odontoma.

    Science.gov (United States)

    Gunda, Sachin A; Patil, Anil; Varekar, Aniruddha

    2013-07-04

    Trauma or infection to the primary tooth may have deleterious effects on the underlying developing tooth buds. Anatomically the root apices of primary teeth are in close proximity to the developing permanent tooth buds; hence spread of infection originating from pulp necrosis of primary tooth may not only affect the underlying tooth bud but may also affect the adjacent tooth buds. The extent of malformation depends on the developmental stage of tooth or the age of patient. Presented here is a rare case of complete arrest of maxillary first permanent molar root growth due to spread of periapical infection originating from second primary molar leading to failure of its eruption and finally extraction. Histopathlogical analysis revealed compound odontoma associated with maxillary first permanent molar.

  1. Factors affecting the development of collaborative improvement with strategic suppliers

    NARCIS (Netherlands)

    Kaltoft, Rasmus; Boer, Harm; Corso, Mariano; Gertsen, Frank; Gieskes, J.F.B.; Middel, H.G.A.; Steendahl Nielsen, Jacob

    2003-01-01

    The research presented in this paper was aimed at increasing the current understanding of the process of developing collaborative improvement in Extended Manufacturing Enterprises (EME). Theory suggests a number of factors to affect that process, including shared sense of direction (i.e. vision),

  2. How does technological regime affect performance of technology development projects?

    NARCIS (Netherlands)

    Song, Michael; Hooshangi, Soheil; Zhao, Y. Lisa; Halman, Johannes I.M.

    2014-01-01

    In this study, we examine how technological regime affects the performance of technology development projects (i.e., project quality, sales, and profit). Technological regime is defined as the set of attributes of a technological environment where the innovative activities of firms take place.

  3. Major constraints affecting aquaculture development in Akwa Ibom ...

    African Journals Online (AJOL)

    The study contributes to nationwide attempts to enhance the contributions of aquaculture to the fishery subsector, and consequent overall gross domestic product of Nigeria, as well as to the protein intake of her citizenry. The focus is on the determination of the magnitude of constraints affecting aquaculture development in ...

  4. Developing Worksheet Based on Science Process Skills: Factors Affecting Solubility

    Science.gov (United States)

    Karsli, Fethiye; Sahin, Cigdem

    2009-01-01

    The purpose of this study is to develop a worksheet about the factors affecting solubility, which could be useful for the prospective science teachers (PST) to remind and regain their science process skills (SPS). The pilot study of the WS was carried out with 32 first grade PST during the 2007-2008 academic year in the education department at…

  5. Investigation on Factors Affecting to the Career Development

    OpenAIRE

    永久, 理恵; 井田, 政則

    2013-01-01

    The factors affecting to the career development were examined in light of the problem with young workers of their job quitting and hopping at early stage. The investigation was carried out with questionnaire given to 277 business persons working in several Japanese companies. We examined how the four major factors consisting of career development, i.e.“organizational socialization”,“ psychological variables of career self-reliance”,“ behavioral variables of career self-reliance”and“ meaning o...

  6. Dental anomaly patterns associated with tooth agenesis.

    Science.gov (United States)

    Choi, Su Ji; Lee, Je Woo; Song, Ji Hyun

    2017-04-01

    The objective of this study is to evaluate the relationship between tooth agenesis and the occurrence of other dental anomalies in children and adolescents. Panoramic radiographs of 195 subjects with tooth agenesis, except for the third molar, were retrospectively examined and compared with a non-agenesis control group of 600 subjects. Their ages ranged from 7 to 15 years. Panoramic and periapical radiographs were used to analyze the presence of other associated dental anomalies. The occurrences of these anomalies were compared with those in the non-agenesis group. Subjects with tooth agenesis showed a significantly higher prevalence of a small maxillary lateral incisor (17.7%), distoangulation of the mandibular second premolar (6.5%), delayed development of a permanent tooth (10.8%), and hypo-occlusion of a primary molar (11.8%). In contrast, the prevalence of a supernumerary tooth was higher in the control group, and no difference was observed in the prevalence of ectopic eruption of a first molar. According to the agenesis area, microdontia of the maxillary lateral incisors occurred more often in patients with anterior or premolar agenesis than in the molar agenesis groups. Distoangulation of the mandibular second premolars, delayed tooth development, and hypo-occlusion of the primary molars were associated with premolar tooth agenesis. A small maxillary lateral incisor, distoangulation of the mandibular second premolar, delayed development of a permanent tooth, and hypo-occlusion of a primary molar were frequently associated with tooth agenesis, providing additional evidence of a genetic interrelationship in the causes of these dental anomalies.

  7. Maternal vitamin A deficiency during pregnancy affects vascularized islet development.

    Science.gov (United States)

    Chien, Chiao-Yun; Lee, Hsuan-Shu; Cho, Candy Hsin-Hua; Lin, Kuo-I; Tosh, David; Wu, Ruei-Ren; Mao, Wan-Yu; Shen, Chia-Ning

    2016-10-01

    Vitamin A deficiency is known to affect 20 million pregnant women worldwide. However, the prenatal effects of maternal vitamin A deficiency on pancreas development have not been clearly determined. The present study examined how maternal vitamin A deficiency affects fetal islet development. Vitamin A-deficient mice were generated by feeding female mice with a chemically defined diet lacking vitamin A prior to mating as well as during pregnancy. We found that maternal vitamin A deficiency during pregnancy affected fetal pancreas development. Although the exocrine differentiation appeared normal, development of islet tissue was impaired. In the pancreas of neonatal mice, only a few endocrine cell clusters were formed, and these cell clusters lacked capillary endothelial cells. To further determine how vitamin A metabolites, such as retinoic acid, regulate vascularized islet development, ex vivo culture of embryonic pancreas either in the presence of 4-diethylaminobenzaldehyde (DEAB; an inhibitor of retinaldehyde dehydrogenase), all-trans retinoic acid (atRA) or retinoic acid receptor agonist (E)-4-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthylenyl)-1-propenyl] benzoic acid (TTNPB) was carried out. We found that the addition of DEAB blocked vascularization and suppressed β-cell differentiation. Conversely, atRA or TTNPB promoted β-cell differentiation accompanied by enhanced expression of vascular basement component, laminin. We further demonstrated that atRA regulated vascularization via upregulating vascular endothelial growth factor-A (VEGF-A) secretion in embryonic pancreas and treatment with VEGF-A was able to partially rescue vascularization and β-cell differentiation in DEAB-treated embryonic pancreas cultures. The findings explain why maternal vitamin A deficiency affects fetal islet development and support an essential role of retinoid signaling in regulating vascularized islet development. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Professional Group Development Trainers’ Personality Characteristics and Affective Profiles

    Directory of Open Access Journals (Sweden)

    Max eRapp Ricciardi

    2014-10-01

    Full Text Available Background: The Development of Groups and Leaders (UGL, provided by the Swedish National Defence College and mentored by UGL-trainers, is one of the most popular management programs among civilians in Sweden. However, there is a lack of scientific evidence regarding the training. We used the affective profile model (i.e., the combination of positive, PA, and negative affect, NA to mapp important markers of empowerment, self-awareness, adaptive coping skills, and maturity among the UGL-trainers. The aims were: (1 to compare profiles between UGL-trainers and managers/supervisors and (2 to investigate differences in personal characteristics.Method: UGL-trainers (N = 153 and the comparison group (104 Swedish Chiefs of Police completed an online survey on optimism, self-esteem, locus of control, and affect. The four profiles are: self-fulfilling (high PA, low NA, high affective (high PA, high NA, low affective (high PA, low NA, and self-destructive (low PA, high NA,Results: The self-fulfilling profile was more common among UGL-trainers (25.70% than among Chiefs of Police (19.20%. UGL-trainers, compared to Chiefs of Police, were more likely to express a self-fulling than a low affective profile (OR=2.22, p < .05 and a high affective than a low affective profile (OR=1.43, p <.001. UGL-trainers with a self-fulfilling profile, compared to those with a self-destructive profile, scored higher in optimism, higher in self-esteem, and lower in external locus of control. Conclusions: The probability of self-fulfilment rather than low affectivity was higher among UGL-trainers. Self-fulfilment was associated to markers of self-awareness and adaptive coping skills. However, the most common profile was the low affective, which is associated to low performance during stress, low degree of personal development, low degree of purpose in life, and low resilience. Hence, it might be important for UGL-trainers to have a continuos training in awareness after

  9. Abiotic tooth enamel

    Science.gov (United States)

    Yeom, Bongjun; Sain, Trisha; Lacevic, Naida; Bukharina, Daria; Cha, Sang-Ho; Waas, Anthony M.; Arruda, Ellen M.; Kotov, Nicholas A.

    2017-03-01

    Tooth enamel comprises parallel microscale and nanoscale ceramic columns or prisms interlaced with a soft protein matrix. This structural motif is unusually consistent across all species from all geological eras. Such invariability—especially when juxtaposed with the diversity of other tissues—suggests the existence of a functional basis. Here we performed ex vivo replication of enamel-inspired columnar nanocomposites by sequential growth of zinc oxide nanowire carpets followed by layer-by-layer deposition of a polymeric matrix around these. We show that the mechanical properties of these nanocomposites, including hardness, are comparable to those of enamel despite the nanocomposites having a smaller hard-phase content. Our abiotic enamels have viscoelastic figures of merit (VFOM) and weight-adjusted VFOM that are similar to, or higher than, those of natural tooth enamels—we achieve values that exceed the traditional materials limits of 0.6 and 0.8, respectively. VFOM values describe resistance to vibrational damage, and our columnar composites demonstrate that light-weight materials of unusually high resistance to structural damage from shocks, environmental vibrations and oscillatory stress can be made using biomimetic design. The previously inaccessible combinations of high stiffness, damping and light weight that we achieve in these layer-by-layer composites are attributed to efficient energy dissipation in the interfacial portion of the organic phase. The in vivo contribution of this interfacial portion to macroscale deformations along the tooth’s normal is maximized when the architecture is columnar, suggesting an evolutionary advantage of the columnar motif in the enamel of living species. We expect our findings to apply to all columnar composites and to lead to the development of high-performance load-bearing materials.

  10. [Mentalisation and affect regulation--how the infantile self develops].

    Science.gov (United States)

    Kalisch, Konrad

    2012-01-01

    The text comprises the different elements of the psychoanalytic mentalization theory of Peter Fonagy et al. and tries to explain them. Part of this theory are above all the affect mirroring as well as the affect reciprocity theory and the two modes of the "as if" character and the psychic equivalence (playing with reality). You can find clear examples for each of these theoretical components. Moreover there are many correlations to other authors and their respective development theories: that is to Wilfred Bion, Donald Winnicott and John Bowlby. The text is based above all on Martin Dornes' approaches on this topic (2004, 2006).

  11. Development and psychometric validation of the verbal affective memory test

    DEFF Research Database (Denmark)

    Jensen, Christian Gaden; Hjordt, Liv V; Stenbæk, Dea S

    2015-01-01

    We here present the development and validation of the Verbal Affective Memory Test-24 (VAMT-24). First, we ensured face validity by selecting 24 words reliably perceived as positive, negative or neutral, respectively, according to healthy Danish adults' valence ratings of 210 common and non...... and converged satisfactorily with established non-affective verbal tests. Immediate recall (IMR) for positive words exceeded IMR for negative words in the healthy sample. Relatedly, individuals with SAD showed a significantly larger decrease in positive recall from summer to winter than healthy controls...... psychometric properties. VAMT-24 seems especially sensitive to measuring positive verbal recall bias, perhaps due to the application of common, non-taboo words. Based on the psychometric and clinical results, we recommend VAMT-24 for international translations and studies of affective memory....

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

    Science.gov (United States)

    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.

  13. Autogenous tooth transplantation for replacing a lost tooth: case reports

    Directory of Open Access Journals (Sweden)

    Ji-Youn Kang

    2013-02-01

    Full Text Available The autogenous tooth transplantation is an alternative treatment replacing a missing tooth when a suitable donor tooth is available. It is also a successful treatment option to save significant amount of time and cost comparing implants or conventional prosthetics. These cases, which required single tooth extraction due to deep caries and severe periodontal disease, could have good results by transplanting non-functional but sound donor tooth to the extraction site.

  14. Primary cilia regulate Shh activity in the control of molar tooth number.

    Science.gov (United States)

    Ohazama, Atsushi; Haycraft, Courtney J; Seppala, Maisa; Blackburn, James; Ghafoor, Sarah; Cobourne, Martyn; Martinelli, David C; Fan, Chen-Ming; Peterkova, Renata; Lesot, Herve; Yoder, Bradley K; Sharpe, Paul T

    2009-03-01

    Primary cilia mediate Hh signalling and mutations in their protein components affect Hh activity. We show that in mice mutant for a cilia intraflagellar transport (IFT) protein, IFT88/polaris, Shh activity is increased in the toothless diastema mesenchyme of the embryonic jaw primordia. This results in the formation of ectopic teeth in the diastema, mesial to the first molars. This phenotype is specific to loss of polaris activity in the mesenchyme since loss of Polaris in the epithelium has no detrimental affect on tooth development. To further confirm that upregulation of Shh activity is responsible for the ectopic tooth formation, we analysed mice mutant for Gas1, a Shh protein antagonist in diastema mesenchyme. Gas1 mutants also had ectopic diastema teeth and accompanying increased Shh activity. In this context, therefore, primary cilia exert a specific negative regulatory effect on Shh activity that functions to repress tooth formation and thus determine tooth number. Strikingly, the ectopic teeth adopt a size and shape characteristic of premolars, a tooth type that was lost in mice around 50-100 million years ago.

  15. Dielectric response of the human tooth dentine

    Energy Technology Data Exchange (ETDEWEB)

    Leskovec, J. [Dental Clinic, Faculty of Medicine, University of Ljubljana, Hrvatski trg 6, 1104 Ljubljana (Slovenia); Filipic, C. [Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana (Slovenia); Levstik, A. [Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana (Slovenia)]. E-mail: adrijan.levstik@ijs.si

    2005-07-15

    Dielectric properties of tooth dentine can be well described by the model which was developed for the dielectric response to hydrating porous cement paste. It is shown that the normalized dielectric constant and the normalized specific conductivity are proportional to the model parameters -bar {sub v0} and {sigma}{sub v}, indicating the deposition of AgCl in the dentine tubules during the duration of the precipitation. The fractal dimension of the tooth dentine was determined by dielectric spectroscopy.

  16. Dielectric response of the human tooth dentine

    International Nuclear Information System (INIS)

    Leskovec, J.; Filipic, C.; Levstik, A.

    2005-01-01

    Dielectric properties of tooth dentine can be well described by the model which was developed for the dielectric response to hydrating porous cement paste. It is shown that the normalized dielectric constant and the normalized specific conductivity are proportional to the model parameters -bar v0 and σ v , indicating the deposition of AgCl in the dentine tubules during the duration of the precipitation. The fractal dimension of the tooth dentine was determined by dielectric spectroscopy

  17. Dielectric response of the human tooth dentine

    Science.gov (United States)

    Leskovec, J.; Filipič, C.; Levstik, A.

    2005-07-01

    Dielectric properties of tooth dentine can be well described by the model which was developed for the dielectric response to hydrating porous cement paste. It is shown that the normalized dielectric constant and the normalized specific conductivity are proportional to the model parameters ɛ and σv, indicating the deposition of AgCl in the dentine tubules during the duration of the precipitation. The fractal dimension of the tooth dentine was determined by dielectric spectroscopy.

  18. The Factors that Affect Science Teachers' Participation in Professional Development

    Science.gov (United States)

    Roux, Judi Ann

    Scientific literacy for our students and the possibilities for careers available in Science, Technology, Engineering, and Mathematics (STEM) areas are important topics for economic growth as well as global competitiveness. The achievement of students in science learning is dependent upon the science teachers' effectiveness and experienced science teachers depend upon relevant professional development experiences to support their learning. In order to understand how to improve student learning in science, the learning of science teachers must also be understood. Previous research studies on teacher professional development have been conducted in other states, but Minnesota science teachers comprised a new and different population from those previously studied. The purpose of this two-phase mixed methods study was to identify the current types of professional development in which experienced, Minnesota secondary science teachers participated and the factors that affect their participation in professional development activities. The mixed-methods approach s utilized an initial online survey followed by qualitative interviews with five survey respondents. The results of the quantitative survey and the qualitative interviews indicated the quality of professional development experiences and the factors which affected the science teachers' participation in professional development activities. The supporting and inhibiting factors involved the availability of resources such as time and money, external relationships with school administrators, teacher colleagues, and family members, and personal intrinsic attributes such as desires to learn and help students. This study also describes implications for science teachers, school administrators, policymakers, and professional development providers. Recommendations for future research include the following areas: relationships between and among intrinsic and extrinsic factors, science-related professional development activities

  19. Tooth brushing for oral prophylaxis

    Directory of Open Access Journals (Sweden)

    Haruaki Hayasaki, DDS, PhD

    2014-08-01

    Full Text Available Control of plaque and debris is essential for the prevention of inflammatory periodontal diseases and dental caries, because plaque is the primary etiological factor in the introduction and development of both of these infection-oriented diseases. Plaque removal with a toothbrush is the most frequently used method of oral hygiene. Powered toothbrushes were developed beginning in the 1960s and are now widely used in developed countries. The bristles of a toothbrush should be able to reach and clean efficiently most areas of the mouth, and recently the design of both manual and powered toothbrushes has focused on the ability to reach and clean interproximal tooth surfaces. An individual's tooth brushing behavior, including force, duration, motivation and motion, are also critical to tooth brushing efficacy. Dental floss and the type of toothpaste play additional important roles as auxiliary tools for oral prophylaxis. Dental professionals should help their care-receivers’ meet the requirements of oral hygiene to maintain their QOL. This article reviews these topics.

  20. Replacing a Missing Tooth

    Science.gov (United States)

    ... there are two options for replacement: First, a removable partial denture may be used to replace the missing tooth. ... appearance look and feel more natural than a removable partial denture. However, it does require grinding down the support ...

  1. To Tell the Tooth

    Science.gov (United States)

    ... 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 Count Puzzle Fun Oral Health Made Easy ...

  2. Endogenous and Exogenous Substances Influencing the Orthodontic Tooth Movement

    Directory of Open Access Journals (Sweden)

    Mine Geçgelen Cesur

    2016-08-01

    Full Text Available Orthodontic tooth movement occurs as a result of prolonged application of controlled mechanical forces. Recent studies have focused on the effects of systemic or local applications of medications and the intake of dietary supplements as well as the mechanical forces. Factors affecting the orthodontic tooth movement are parathyroid hormone, thyroid hormones, estrogen, vitamin D3, eicosanoids, nonsteroidal anti-inflammatory drugs (NSAIDs, paracetamol, corticosteroids, bisphosphonates, cholesterol drugs, anticonvulsants, oral contraceptives, alcohol and nicotine use, nitric oxide, and fluoride. These medications have an important effect on the rate of tooth movement and treatment time. NSAIDs decrease tooth movement, but paracetamol has no effect. Parathyroid and thyroxin hormones increase tooth movement. Bisphosphonates have a strong inhibitory effect. Vitamin D3 stimulates tooth movement and dietary calcium seems to reduce it. It is important to discuss with patients about the consumption of these substances during orthodontic treatment.

  3. Development of affective modelling competencies in primary school learners

    Directory of Open Access Journals (Sweden)

    Piera Biccard

    2011-09-01

    Full Text Available Learner affect and beliefs about mathematics are complex and multifaceted aspects of mathematical learning. Traditional teaching and learning approaches in mathematics education often result in problematic beliefs about mathematics. Since beliefs influence what learners learn and how they deal with learning mathematics, it is essential that the roles of beliefs and affect in mathematics classrooms are carefully examined. In solving modelling problems, learners and teachers take on new roles in the classroom: learners are placed in an active, self-directing situation in which they solve real-world problems. When learners engage in modelling tasks, they display and integrate cognitive, meta-cognitive and affective competencies. A modelling approach therefore allows one to detect learner beliefs in an authentic learning environment. Will this environment lead to students having more positive and productive dispositions towards mathematics? This article presents partial results of a study documenting the development of modelling competencies in learners working in groups over a period of 12 weeks. Through a design research approach, 12 learners working in groups solved three modelling problems, and transcriptions of learner interactions, questionnaires and informal interviews revealed that learner beliefs improved over this short period when exposed to modelling tasks. The results are encouraging, and may provide mathematics education with an avenue to develop more positive learner beliefs in mathematics.

  4. Development of affective modelling competencies in primary school learners

    Directory of Open Access Journals (Sweden)

    Piera Biccard

    2011-10-01

    Full Text Available Learner affect and beliefs about mathematics are complex and multifaceted aspects of mathematical learning. Traditional teaching and learning approaches in mathematics education often result in problematic beliefs about mathematics. Since beliefs influence what learners learn and how they deal with learning mathematics, it is essential that the roles of beliefs and affect in mathematics classrooms are carefully examined. In solving modelling problems, learners and teachers take on new roles in the classroom: learners are placed in an active, self-directing situation in which they solve real-world problems. When learners engage in modelling tasks, they display and integrate cognitive, meta-cognitive and affective competencies. A modelling approach therefore allows one to detect learner beliefs in an authentic learning environment. Will this environment lead to students having more positive and productive dispositions towards mathematics? This article presents partial results of a study documenting the development of modelling competencies in learners working in groups over a period of 12 weeks. Through a design research approach, 12 learners working in groups solved three modelling problems, and transcriptions of learner interactions, questionnaires and informal interviews revealed that learner beliefs improved over this short period when exposed to modelling tasks. The results are encouraging, and may provide mathematics education with an avenue to develop more positive learner beliefs in mathematics.

  5. Tooth -Wear Lesions Among Patients Attending Tertiary Hospital in ...

    African Journals Online (AJOL)

    Tooth wear manifest in the form of abrasion, attrition, erosion and abfraction and can affect the quality of life of the sufferer. This was a prospective study of patients who ... We recommend oral hygiene advice, dietary counseling and regular dental examination for early detection. Key words: Tooth wear, lesion, prospective, ...

  6. Pink tooth phenomenon: an enigma?

    Science.gov (United States)

    Thapar, Raveena; Choudhry, Swati; Sinha, Anju; Bali, Ruchita; Shukla, Deepika

    2013-10-01

    The appearance of pink teeth is a common phenomenon which has been observed after death in certain circumstances on post-mortem examination. Extra fibrinolytic activity of pulp facilitates rapid breakdown of red blood cells and diffusion of hemoglobin and its derivatives to flow into dentine. We reviewed various studies on pink tooth phenomenon which have stated the various factors that lead to pink tooth formation. Most of the authors have stressed that post-mortem pink teeth must not be considered as a reliable odontological parameter for determining cause of death. No correlation has been found between the occurrence of pink teeth and the cause of death but condition of the surroundings certainly plays an important role in the development of this phenomenon. This paper reviews the factors and conditions responsible for formation of pink teeth. Copyright © 2013 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  7. Charcot–Marie–Tooth disease

    Science.gov (United States)

    Szigeti, Kinga; Lupski, James R

    2009-01-01

    Charcot-Marie-Tooth (CMT) disease is a heterogeneous group of genetic disorders presenting with the phenotype of a chronic progressive neuropathy affecting both the motor and sensory nerves. During the last decade over two dozen genes have been identified in which mutations cause CMT. The disease illustrates a multitude of genetic principles, including diverse mutational mechanisms from point mutations to copy number variation (CNV), allelic heterogeneity, age-dependent penetrance and variable expressivity. Population based studies have determined the contributions of the various genes to disease burden enabling evidence-based approaches to genetic testing. PMID:19277060

  8. Influence of self-esteem and negative affectivity on oral health related quality of life in patients with partial tooth loss

    DEFF Research Database (Denmark)

    Øzhayat, Esben Boeskov

    2013-01-01

    To meaningfully interpret oral health-related quality of life (OHRQoL) measures, the influence of personality traits must be investigated. Objectives:To investigate and quantify the influence of self-esteem and negative affectivity (NA) on OHRQoL. It was hypothesized that low self-esteem and high...... NA would be associated with worse OHRQoL.Methods: OHRQoL measured by the Oral Health Impact Profile 49 (OHIP-49), self-esteem measured by the Rosenberg Self-Esteem Scale (RSES), NA measured by the Eysenck Personality Inventory Questionnaire (EPI-Q), global oral rating of oral comfort and controlling...... and clinically significantly higher and self-esteem was statistically significantly lower in patients reporting worse oral comfort. Conclusion: NA had the strongest and most clinically meaningful influence, but both NA and self-esteem was found to influence OHRQoL; low self-esteem and high NA was associated...

  9. Factors affecting adipose tissue development in chickens: A review.

    Science.gov (United States)

    Wang, Guoqing; Kim, Woo Kyun; Cline, Mark A; Gilbert, Elizabeth R

    2017-10-01

    The intense genetic selection for rapid growth in broilers has resulted in an increase in voluntary feed intake and growth rate, accompanied by increased fat deposition in adipose tissue depots throughout the body. Adipose tissue expansion is a result of the formation of adipocytes (several processes collectively referred to as adipogenesis) and cellular accumulation of triacylglycerols inside lipid droplets. In mammals, different anatomical depots are metabolically distinct. The molecular and cellular mechanisms underlying adipose tissue development have been characterized in mammalian models, whereas information in avian species is scarce. The purpose of this review is to describe factors regulating adipogenesis in chickens, with an emphasis on dietary factors and the broiler. Results from many studies have demonstrated effects of dietary nutrient composition on adipose tissue development and lipid metabolism. Transcription factors, such as peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding proteins α and β, and sterol regulatory element binding proteins orchestrate a series of cellular events that lead to an increase in activity of fatty acid transport proteins and enzymes that are responsible for triacylglycerol synthesis. Understanding the mechanisms underlying adipose tissue development may provide a practical strategy to affect body composition of the commercial broiler while providing insights on diets that maximize conversion into muscle rather than fat and affect depot-dependent deposition of lipids. Because of the propensity to overeat and become obese, the broiler chicken also represents an attractive biomedical model for eating disorders and obesity in humans. © 2017 Poultry Science Association Inc.

  10. How Stock Markets Development Affect Endogenous Growth Theory

    Directory of Open Access Journals (Sweden)

    Najeb Masoud

    2013-10-01

    Full Text Available This paper can bedescribed as a significant exploratory study that will provide a significantcontribution to knowledge to consider crucial issues which need to be barriersto understanding or a temptation/ requirement to judge some practices as‘better’ than others for stock market development effective approach andimplement successful stock market performance and economic growth. Recentanalysis of the link between financial development and growth, gained frominsights acquired as a result of using the technique of endogenous growthmodels, has illustrated that growth without exogenous technical progress andthat growth rates could be related to technology, income distribution andinstitutional arrangements. This provides the theoretical background thatempirical studies have lacked; illustrating that financial intermediationaffects the level of economic growth. Resulting models have provided newimpetus to empirical research of the effects of financial development. Thebirth of the new endogenous growth theory has facilitated the development ofimproved growth models where the long-term rate could be affected by a numberof elements. These included technology, education and health policies in theprocess of economic development, capital accumulation, government policies andinstitutional activities in the role of financial development in economicgrowth.

  11. Influence of metabolic-linked early life factors on the eruption timing of the first primary tooth.

    Science.gov (United States)

    Un Lam, Carolina; Hsu, Chin-Ying Stephen; Yee, Robert; Koh, David; Lee, Yung Seng; Chong, Mary Foong-Fong; Cai, Meijin; Kwek, Kenneth; Saw, Seang Mei; Godfrey, Keith; Gluckman, Peter; Chong, Yap Seng

    2016-11-01

    Early eruption of permanent teeth has been associated with childhood obesity and diabetes mellitus, suggesting links between tooth eruption and metabolic conditions. This longitudinal study aimed to identify pre-, peri- and postnatal factors with metabolic consequences during infancy that may affect the eruption timing of the first primary tooth (ETFT) in children from an ethnically heterogeneous population residing within the same community. Participants were recruited (n = 1033) through the GUSTO (Growing Up in Singapore Towards healthy Outcomes) birth cohort (n = 1237). Oral examinations were performed at 3-month intervals from 6 to 18 months of age. Crude and adjusted analyses, with generalized linear modelling, were conducted to link ETFT to potential determinants occurring during pregnancy, delivery/birth and early infancy. Overall mean eruption age of the first primary tooth was 8.5 (SD 2.6) months. Earlier tooth eruption was significantly associated with infant's rate of weight gain during the first 3 months of life and increased maternal childbearing age. Compared to their Chinese counterparts, Malay and Indian children experienced significantly delayed tooth eruption by 1.2 and 1.7 months, respectively. Infant weight gain from birth to 3 months, ethnicity and maternal childbearing age were significant determinants of first tooth eruption timing. Early life influences can affect primary tooth development, possibly via metabolic pathways. Timing of tooth eruption is linked to general growth and metabolic function. Therefore, it has potential in forecasting oral and systemic conditions such as caries and obesity.

  12. Biological approach for management of anterior tooth trauma: Triple case report

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    Goenka P

    2010-09-01

    Full Text Available Anterior crown fractures are a common form of injury that mainly affect children and adolescents. The position of maxillary incisors and their eruptive pattern carries a significant risk for trauma. In the pre-adhesive era, fractured teeth needed to be restored either with pin-retained inlays or cast restorations that sacrificed healthy tooth structure and were a challenge for clinicians to match with adjacent teeth. The development of adhesive dentistry has allowed dentists to use the patient′s own fragment to restore the fractured tooth. Three cases are presented here with complicated crown fracture of maxillary central incisors; the reattachment of the fractured tooth segment in this case has been performed using different combinations of techniques, viz. simple reattachment, circumferential bevel and internal dentinal groove.

  13. Biological approach for management of anterior tooth trauma: Triple case report

    Directory of Open Access Journals (Sweden)

    Puneet Goenka

    2011-01-01

    Full Text Available Anterior crown fractures are a common form of injury that mainly affect children and adolescents. The position of maxillary incisors and their eruptive pattern carries a significant risk for trauma. In the pre-adhesive era, fractured teeth needed to be restored either with pin-retained inlays or cast restorations that sacrificed healthy tooth structure, and were a challenge for clinicians to match with adjacent teeth. The development of adhesive dentistry has allowed dentists to use the patient′s own fragment to restore the fractured tooth. Three cases are presented here with complicated crown fracture of maxillary central incisors; the reattachment of the fractured tooth segment in these cases has been performed using different combinations of techniques, viz. simple reattachment, circumferential bevel and internal dentinal groove.

  14. 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.

  15. Malnutrition has no effect on the timing of human tooth formation.

    Directory of Open Access Journals (Sweden)

    Fadil Elamin

    Full Text Available The effect of nutrition on the timing of human tooth formation is poorly understood. Delays and advancements in dental maturation have all been reported as well as no effect. We investigated the effect of severe malnutrition on the timing of human tooth formation in a large representative sample of North Sudanese children. The sample (1102 males, 1013 females consisted of stratified randomly selected healthy individuals in Khartoum, Sudan, aged 2-22 years using a cross-sectional design following the STROBE statement. Nutritional status was defined using WHO criteria of height and weight. Body mass index Z-scores and height for age Z-scores of ≤-2 (cut-off were used to identify the malnourished group (N = 474 while the normal was defined by Z-scores of ≥0 (N = 799. Clinical and radiographic examination of individuals, with known ages of birth was performed including height and weight measurements. Mandibular left permanent teeth were assessed using eight crown and seven root established tooth formation stages. Mean age at entry and mean age within tooth stages were calculated for each available tooth stage in each group and compared using a t-test. Results show the mean age at entry and mean age within tooth stages were not significantly different between groups affected by severe malnutrition and normal children (p>0.05. This remarkable finding was evident across the span of dental development. We demonstrate that there is little measurable effect of sustained malnutrition on the average timing of tooth formation. This noteworthy finding supports the notion that teeth have substantial biological stability and are insulated from extreme nutritional conditions compared to other maturing body systems.

  16. Development of brain mechanisms for processing affective touch

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    Malin eBjornsdotter

    2014-02-01

    Full Text Available Affective tactile stimulation plays a key role in the maturation of neural circuits, but the development of brain mechanisms processing touch is poorly understood. We therefore used functional magnetic resonance imaging (fMRI to study brain responses to soft brush stroking of both glabrous (palm and hairy (forearm skin in healthy children (5-13 years, adolescents (14-17 years and adults (25-35 years. Adult-defined regions-of-interests in the primary somatosensory cortex (SI, secondary somatosensory cortex (SII, insular cortex and right posterior superior temporal sulcus (pSTS were significantly and similarly activated in all age groups. Whole-brain analyses revealed that responses in the ipsilateral SII were positively correlated with age in both genders, and that responses in bilateral regions near the pSTS correlated significantly and strongly with age in females but not in males. These results suggest that brain mechanisms associated with both sensory-discriminative and affective-motivational aspects of touch are largely established in school-aged children, and that there is a general continuing maturation of SII and a female-specific increase in pSTS sensitivity with age. Our work establishes a groundwork for future comparative studies of tactile processing in developmental disorders characterized by disrupted social perception such as autism.

  17. Biomaterial Selection for Tooth Regeneration

    Science.gov (United States)

    Yuan, Zhenglin; Nie, Hemin; Wang, Shuang; Lee, Chang Hun; Li, Ang; Fu, Susan Y.; Zhou, Hong

    2011-01-01

    Biomaterials are native or synthetic polymers that act as carriers for drug delivery or scaffolds for tissue regeneration. When implanted in vivo, biomaterials should be nontoxic and exert intended functions. For tooth regeneration, biomaterials have primarily served as a scaffold for (1) transplanted stem cells and/or (2) recruitment of endogenous stem cells. This article critically synthesizes our knowledge of biomaterial use in tooth regeneration, including the selection of native and/or synthetic polymers, three-dimensional scaffold fabrication, stem cell transplantation, and stem cell homing. A tooth is a complex biological organ. Tooth loss represents the most common organ failure. Tooth regeneration encompasses not only regrowth of an entire tooth as an organ, but also biological restoration of individual components of the tooth including enamel, dentin, cementum, or dental pulp. Regeneration of tooth root represents perhaps more near-term opportunities than the regeneration of the whole tooth. In the adult, a tooth owes its biological vitality, arguably more, to the root than the crown. Biomaterials are indispensible for the regeneration of tooth root, tooth crown, dental pulp, or an entire tooth. PMID:21699433

  18. Factors affecting the insurance sector development: Evidence from Albania

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    Eglantina Zyka

    2014-03-01

    Full Text Available In this paper we explore factors potentially affecting the size of Albanian insurance market, over the period 1999 to 2009. The results of co- integration regression show that GDP and fraction urban population, both one lagged value, size of population and paid claims, both at contemporary value, have significant positive effect on aggregate insurance premium in Albania while the market share of the largest company in the insurance market, one lagged value, has significant negative effect on aggregate insurance premiums. Granger causality test shows statistically significance contribution of GDP growth to insurance premium growth, GDP drives insurance premium growth but not vice versa. The Albanian insurance market is under development, indicators as: insurance penetration, premium per capita, ect are still at low level and this can justify the insignificant role of the insurance in the economy

  19. Performance strategies affect mammary gland development in prepubertal heifers.

    Science.gov (United States)

    Albino, R L; Sguizzato, A L; Daniels, K M; Duarte, M S; Lopes, M M; Guimarães, S E F; Weller, M M D C A; Marcondes, M I

    2017-10-01

    In Brazil, the majority of dairy cattle are Holstein × Gyr (H×G). It is unknown whether excessive energy intake negatively affects their mammary development to the same extent as in purebred Holsteins. We hypothesized that mammary development of H×G heifers can be affected by dietary energy supply. We evaluated the effect of different average daily gains (ADG) achieved by feeding different amounts of a standard diet during the growing period on biometric measurements, development of mammary parenchyma (PAR) and mammary fat pad (MFP), and blood hormones. At the outset of this 84-d experiment, H×G heifers (n = 18) weighed 102.2 ± 3.4 kg and were 3 to 4 mo of age. Heifers were randomly assigned to 1 of 3 ADG programs using a completely randomized design. Treatments were high gain (HG; n = 6), where heifers were fed to gain 1 kg/d; low gain (LG; n = 6), where heifers were fed to gain 0.5 kg/d; and maintenance (MA; n = 6), where heifers were fed to gain a minimal amount of weight per day. Heifers were fed varying amounts of a single TMR to support desired BW gains. Over the 84 d, periodic biometric and blood hormone measurements were obtained. On d 84, all heifers were slaughtered and carcass and mammary samples were collected. At the end, HG heifers weighed the most (181 ± 7.5 kg), followed by LG (146 ± 7.5 kg) and MA (107 ± 7.5 kg) heifers. The ADG were near expected values and averaged 0.907, 0.500, and 0.105 ± 0.03 kg/d for HG, LG, and MA, respectively. In addition, body lengths, heart girths, and withers heights were affected by dietary treatment, with MA heifers generally being the smallest and HG heifers generally being the largest. Body condition scores differed by treatment and were highest in HG and lowest in MA heifers; in vivo subcutaneous fat thickness measurement and direct analysis of carcass composition supported this. The HG heifers had the heaviest MFP, followed by LG and then MA heifers. Amount of PAR was highest in LG heifers and was the

  20. Triple dens invaginatus in a single tooth: Rarest of rare case report.

    Science.gov (United States)

    Chhina, Amandeep; Chhina, Kamalpreet; Kaushal, Nitin; Walia, Ira

    2017-01-01

    Dens invaginatus is a rare malformation affecting the teeth. The teeth that are most commonly affected are the permanent maxillary lateral incisors. The mandibular posterior teeth are rarely affected by dens invaginatus. In most of the cases, a single dens invaginatus is seen affecting the tooth. Cases of double dens invaginatus affecting a single tooth are rare, and those of triple dens invaginatus in a single tooth are even rarer. Here, we present a case of a 14-year-old where three dens invaginatus were seen in the mandibular second premolar. This is the fourth case of three dens invaginatus in a single tooth as only three have been reported previously.

  1. Ionizing radiation from Chernobyl affects development of wild carrot plants

    Science.gov (United States)

    Boratyński, Zbyszek; Arias, Javi Miranda; Garcia, Cristina; Mappes, Tapio; Mousseau, Timothy A.; Møller, Anders P.; Pajares, Antonio Jesús Muñoz; Piwczyński, Marcin; Tukalenko, Eugene

    2016-12-01

    Radioactivity released from disasters like Chernobyl and Fukushima is a global hazard and a threat to exposed biota. To minimize the deleterious effects of stressors organisms adopt various strategies. Plants, for example, may delay germination or stay dormant during stressful periods. However, an intense stress may halt germination or heavily affect various developmental stages and select for life history changes. Here, we test for the consequence of exposure to ionizing radiation on plant development. We conducted a common garden experiment in an uncontaminated greenhouse using 660 seeds originating from 33 wild carrots (Daucus carota) collected near the Chernobyl nuclear power plant. These maternal plants had been exposed to radiation levels that varied by three orders of magnitude. We found strong negative effects of elevated radiation on the timing and rates of seed germination. In addition, later stages of development and the timing of emergence of consecutive leaves were delayed by exposure to radiation. We hypothesize that low quality of resources stored in seeds, damaged DNA, or both, delayed development and halted germination of seeds from plants exposed to elevated levels of ionizing radiation. We propose that high levels of spatial heterogeneity in background radiation may hamper adaptive life history responses.

  2. STUDY OF FACTORS AFFECTING DEVELOPMENT OF FOOD AROMATIZATION

    Directory of Open Access Journals (Sweden)

    Н.Ye. Dubova

    2017-10-01

    Full Text Available The specific understanding of food philosophy according to the facts of development of cooking technologies and growth rate of food range is given. As it has been proven by historical stages of production of flavorings, aroma is one of the important organoleptic ingredients for food developers. A review of food production based on development of nanotechnologies, as well as promising and cautioning publications on nanotechnologies in the food sector is presented. On the basis of the literary analysis, the future impact of nanotechnologies on the evolution of the aromatization process of food products is predicted. It has been determined that the peculiarity of the development mentioned above lies in the use of plant enzymes and / or flavor precursors in the nanoscale range. The example of enzymatic breakdown of polyunsaturated fatty acids of plant cell membranes as one of the ways of creating fresh flavor of many fruits, namely C6-C9 aldehydes and alcohols, is considered. It is noted that green fresh aromatic ingredients are needed to improve the organoleptic profile of foods from heat-treated vegetables, melons and gourds. The following factors affecting the development of food aromatization are defined: the decreased differentiation of principles of healthy nutrition and fast food, repetition of natural processes of aroma formation, application of wild green leafy vegetables, and evolution of medical nutrition. The information on food aromatization by packing with autonomous mixing and their approximate assortment is given. The innovations in food aromatization are aimed at quality nutrition, time saving, recreation and entertainment, meeting specific needs (vegetarian dishes, restrictive diets.

  3. Economic and geographic factors affecting the development of Greater Baku

    Directory of Open Access Journals (Sweden)

    Vusat AFANDIYEV

    2014-12-01

    Full Text Available Globally, the responsible factors for the ongoing development of urbanization are the high speed of population growth, and the mass migration of humans to cities and large urban areas. In most countries, this process resulted in the emergence of ‘pseudo-urbanization’ which is difficult to be regulated. The purpose of the carried researches to determine the development priorities in the territory of Greater Baku – the capital city of the Republic of Azerbaijan; to define the problems that take place in this connection; and to develop ways of elimination of these problems. The reason of taking Baku as a research area is connected with some of the factors. Firstly, studies on Baku have been conducted based on the Soviet geographical and urban planning school and their methods for a long period. In this regard, it is necessary to carry out research in this field based on the principles adopted in most countries. Secondly, since 1992, the intensive accumulation of population in the territory of the capital city and the surrounding areas is being observed because of socio-economic problems. As a result, the process of pseudo-urbanization intensified, entailing a densely-populated area. Thirdly, low-rise buildings still continue to exist in the large areas within the territory of Baku, and they are not associated with the functional structure of the city. This situation creates many challenges, particularly in terms of density growth and effective use of the city’s territory. Finally, numerous new buildings have been constructed in the residential areas of Baku in recent years, and this may entailserious problems in water supply, energy provision, and utilities. The study is carried out referring to previous works of researchers, statistic data, and the results of the population census conducted in 1959-2009.The practical significance of the scientific work is that positive and negative factors affecting the further development of Greater Baku

  4. Save-a-tooth: Conservative surgical management of dentigerous cyst

    Directory of Open Access Journals (Sweden)

    Shivaprakash P

    2009-03-01

    Full Text Available Dentigerous cysts are the most common bony lesions of the jaws in children. It is one of the most prevalent types of odontogenic cysts associated with an erupted or developing tooth, particularly the mandibular third molars; the other teeth that are commonly affected are, in order of frequency, the maxillary canines, the maxillary third molars, and rarely the central incisors. Radiographically, the cyst appears as ovoid well-demarcated unilocular radiolucency with a sclerotic border. Careful evaluation of the history and the clinical and radiographical findings help clinicians to currently diagnose the condition, identify the etiological factors, and administer the appropriate treatment.

  5. Mechanisms of tooth eruption and orthodontic tooth movement.

    Science.gov (United States)

    Wise, G E; King, G J

    2008-05-01

    Teeth move through alveolar bone, whether through the normal process of tooth eruption or by strains generated by orthodontic appliances. Both eruption and orthodontics accomplish this feat through similar fundamental biological processes, osteoclastogenesis and osteogenesis, but there are differences that make their mechanisms unique. A better appreciation of the molecular and cellular events that regulate osteoclastogenesis and osteogenesis in eruption and orthodontics is not only central to our understanding of how these processes occur, but also is needed for ultimate development of the means to control them. Possible future studies in these areas are also discussed, with particular emphasis on translation of fundamental knowledge to improve dental treatments.

  6. ROLE OF BACTERIA IN THE TOOTH ABSCESS: A MINI REVIEW

    OpenAIRE

    Biswajit Batabyal; Gautam kr. Kundu

    2013-01-01

    A tooth abscess or root abscess is pus enclosed in the tissues of the jaw bone at the apex of an infected tooth's root(s). Usually the abscess originates from a bacterial infection that has accumulated in the soft, often dead, pulp of the tooth. This can be caused by untreated tooth decay, cracked teeth or extensive periodontal disease. A failed root canal treatment may also create a similar abscess. Recently developed molecular methods have made it possible to characterise mixed micro flora ...

  7. Tooth development disorders in infants of rat dams exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin and protective role of tocopherol and acetylsalicylic acid.

    Science.gov (United States)

    Dobrzyński, M; Kaczmarek, U; Kuropka, P; Reichert, P; Grzech-Leśniak, K; Całkosiński, I

    2017-12-01

    Aryl hybrocardon receptor (AhR) activation plays a key role in the pathomechanism of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced defective spatial structure of teeth caused by disordered collagen synthesis. The aim of this study was to identify the influence of dioxins present in female Buffalo rats on the dental structure of their offspring's in the neonatal period and the potential of α-tocopherol and acetylsalicylic acid in curbing post-dioxin hard tissue defects. Research material consisted of molar teeth (n=40) of rat pups which had been given a single dose of TCDD and were then treated with tocopherol or acetylsalicylic acid for 3 weeks. In the offspring of rat dams exposed to TCDD, ameloblasts and odontoblasts were less developed in comparison with the control group and less dynamic angiogenesis in the area of dental papilla was observed. In the pups of TCDD-exposed mothers, a smaller number of AhR was found in amelogenic and odontoblastic cells, whereas in the pups of mothers exposed to TCDD followed by tocopherol and acetylsalicylic acid treatment, the expression of AhR in ameloblasts and odontoblasts increased. We conclude that tocopherol and acetylsalicylic acid treatment exerts a protective effect on the TCDD-induced structural defects of tooth tissue. Copyright© by the Polish Academy of Sciences.

  8. Gender differences in factors affecting health care administration career development.

    Science.gov (United States)

    Walsh, A; Borkowski, S C

    1995-01-01

    At first glance, a woman's prospects for a career in health administration seem encouraging. More than half of the recent graduates of health administration master's programs are female, and initially post-master's salaries are comparable with those of male graduates. Unfortunately, opportunities for promotion and financial benefits seem to decrease for women and expand for men as their respective careers progress. This study found that, with the same educational background, men earned an average of $51,491 annually, compared to $50,839 for women, in health care administration. We examined gender differences in organizational and individual factors that have been modeled as influences on career development. These factors include financial and nonfinancial benefits, access to training programs, success factors, demographics, and motivating factors underlying education, employment, and career choices. Some evidence of gender differences in the organizational and individual factors affecting career development is provided. Academic and professional strategies addressing these differences are suggested for consideration by both professional and university administrators.

  9. Does petroleum development affect burrowing owl nocturnal space-use?

    Energy Technology Data Exchange (ETDEWEB)

    Scobie, Corey; Wellicome, Troy; Bayne, Erin [Department of Biological Sciences, University of Alberta (Canada)], email: cscobie@ualberta.ca, email: tiw@ualberta.ca, email: bayne@ualberta.ca

    2011-07-01

    Decline all over Canada in the population of burrowing owls, a federally listed endangered species, has raised concerns about the possible influence of petroleum infrastructure development on owl nocturnal space-use while foraging. Roads, wells, pipelines and sound-producing facilities related to petroleum development change the landscape and can influence the owls' mortality risk. For 3 years, 27 breeding adult male burrowing owls with nests close to different petroleum infrastructures were captured and fitted with a miniature GPS datalogger in order to track their nocturnal foraging. Data from these GPS devices were fed into a geographical information system and showed that pipelines and wells did not alter the foraging habits of the owls. Dirt and gravel roads, with little traffic, were preferentially selected by the owls, conceivably because of higher owl mortality risk along paved roads. Sound-producing facilities did not change owls' foraging behaviour, implying that sound may not affect their nocturnal space-use. Traffic data and sound power measurements will be used in further studies in an effort to better understand burrowing owls' nocturnal foraging habits.

  10. The cracked tooth syndrome.

    Science.gov (United States)

    Lynch, Christoper D; McConnell, Robert J

    2002-09-01

    The purpose of this article is to review the clinical features, diagnosis and management of the cracked tooth syndrome (CTS). The condition refers to an incomplete fracture of a vital posterior tooth that occasionally extends into the pulp. A lack of awareness of the condition coupled with its varied clinical features can make diagnosis of CTS difficult. Common symptoms include an uncomfortable sensation or pain from a tooth that occurs while chewing hard foods and which ceases when the pressure is withdrawn. The patient is often unable to identify the offending tooth or quadrant involved, and may report a history of numerous dental procedures with unsatisfactory results. Successful diagnosis and management requires an awareness of the existence of CTS and the appropriate diagnostic tests. Management options depend on the nature of the symptoms and extent of the lesion. These options include routine monitoring, occlusal adjustments, placement of a cast restoration and endodontic treatment. A decision flowchart indicating the treatment options available to the dental practitioner is presented.

  11. Long-term provisional anterior tooth replacement using fiber-reinforced composite and avulsed tooth crowns as pontics.

    Science.gov (United States)

    Yurdagüven, Haktan; Say, Esra Can; Güler, Nurhan

    2010-02-01

    The loss of anterior teeth due to trauma requires immediate attention for function and esthetics. While implant- supported or conventional fixed prostheses may be the treatments of choice for adults, relatively noninvasive and reversible provisional procedures for tooth replacement are necessary for adolescents. In recent years, developments in fiber and composite technology offer a conservative treatment approach to restore the anterior edentulous space as a fixed provisional tooth replacement. This case report presents the chairside procedures of anterior tooth replacement in an adolescent using the avulsed tooth crowns as pontics which were bonded to teeth on either side of the edentulous space and reinforced with a preimpregnated fiber.

  12. Histology of tooth attachment tissues and plicidentine in Varanus (Reptilia: Squamata), and a discussion of the evolution of amniote tooth attachment.

    Science.gov (United States)

    Maxwell, Erin E; Caldwell, Michael W; Lamoureux, Denis O; Budney, Lisa A

    2011-10-01

    Few recent studies have examined the histological basis for tooth attachment in squamates. In the past few years, a surge of interest in this topic has led to the intriguing suggestion that the major tissues derived from the tooth germ (enamel, dentine, cementum and alveolar bone), are conservative and are present in all amniotes. In this study, we describe the histology and development of the tooth attachment complex in Varanus rudicollis, the rough-neck monitor. We provide the first published evidence for the role of cementum and alveolar bone in tooth attachment in varanoid lizards. In Varanus, cementum is deposited on the external surface of the tooth root as well as at the base of the tooth, where it plays a role in the attachment of the tooth to the jawbone. Alveolar bone is also involved in tooth ankylosis. Our results support the hypothesis that the major tooth germ tissues are found in all amniotes. We provide insights into the structure and development of plicidentine, defined as infolding of the dentine around the tooth base. This feature is unique to varanoids among extant tetrapods and is the third tissue implicated in tooth attachment in Varanus. Plicidentine develops asymmetrically along the labial-lingual axis of a tooth. Varanus is characterized by the presence of both primary and higher-order lamellae, which anastomose to form a honeycomb-like surface that then interacts with the more basal attachment tissues. Copyright © 2011 Wiley-Liss, Inc.

  13. Role of the Wnt signaling molecules in the tooth

    Directory of Open Access Journals (Sweden)

    Masato Tamura, PhD, DDS

    2016-11-01

    Full Text Available Wnt signaling plays a central role in many processes during embryonic development and adult homeostasis. At least 19 types of Wnt ligands, receptors, transducers, transcription factors, and antagonists have been identified in mammals. Two distinct Wnt signaling pathways, the canonical signaling pathway and the noncanonical signaling pathway, have been described. Some Wnt signaling pathway components are expressed in the dental epithelium and mesenchyme during tooth development in humans and mice. Functional studies and experimental analysis of relevant animal models confirm the effects of Wnt signaling pathway on the regulation of developing tooth formation and adult tooth homeostasis. Mutations in some Wnt signaling pathway components have been identified in syndromic and non-syndromic tooth agenesis. This review provides an overview of progress in elucidating the role of Wnt signaling pathway components in the tooth and the resulting possibilities for therapeutic development.

  14. Facial affect recognition in autism, ADHD and typical development.

    Science.gov (United States)

    Berggren, Steve; Engström, Ann-Charlotte; Bölte, Sven

    2016-05-01

    Autism spectrum disorder (ASD) and Attention-Deficit Hyperactivity Disorder (ADHD) have been associated with facial affect recognition (FAR) alterations. This study examined accuracy and response times for general and specific FAR in whole face and eye-region stimuli. FAR was assessed in matched samples of children and adolescents with ASD (n = 35), ADHD (n = 32), and typical development (TD) (n = 32) aged 8.6-15.9 years (M = 11.6; SD = 2.0). Compared to TD, the ASD group performed less accurate and showed longer response times for general and specific FAR, mostly driven by problems in neutral and happy face identification. The ADHD group responded faster than the ASD group for global FAR. No differences between ADHD and TD were found. Attentional distractibility had a significant effect on FAR performance in ASD and ADHD. Findings confirm FAR alterations in ASD, but not ADHD, and endorse effects of attentional distractibility on FAR in ASD and ADHD. FAR and attention function training is clinically meaningful in ASD. Future studies should include control for visual attention and facial configuration skills, use naturalistic FAR material and also investigate implicit FAR.

  15. Preliminary study on a miniature laser manipulation robotic device for tooth crown preparation.

    Science.gov (United States)

    Wang, Dangxiao; Wang, Lei; Zhang, Yuru; Lv, Peijun; Sun, Yuchun; Xiao, Jing

    2014-12-01

    The existing methods in dental clinical operations for hard tissue removal have several drawbacks which affect the long-term success of the dental treatment. In this paper, we introduce a miniature robotic device called LaserBot, which can manipulate a femtosecond laser beam to drill/burr a decayed tooth to realize clinical tooth crown preparation. In order to control the 3D motion of the laser focal point on the surface of a tooth, three miniature voice-coil motors with optical grating rulers are utilized to drive the 2D pitch/yaw rotation of a vibration mirror and 1D translation of a protruding optical lens. This method can provide high-resolution control of the laser beam. In order to maintain the small size of the robot, a parallel five linkage mechanism combined with a slider-rocker mechanism is developed to realize 2D pitch/yaw rotation of the vibration mirror. Experiment results show that the movement range and resolution of the laser beam point can meet the requirement of typical dental operations. The size of the working end of the device that enters the mouth is 25 × 22 × 57 mm (height × width × length), which is small enough to be mounted on any tooth. The average repeatability error of the laser focal point is about 40 µm. Ablation experiments on wax-resin material and on tooth validate that a femtosecond laser can be used for tooth ablation. The developed robotic device achieved precise 3D motion control of a laser focal point and is small enough to be used in the narrow workspace of the oral cavity. Limitations of the prototype have been identified, and quantified specifications are identified for designing the next generation prototype. Copyright © 2014 John Wiley & Sons, Ltd.

  16. Dynamics of Learner Affective Development in Early FLL

    Science.gov (United States)

    Mihaljevic Djigunovic, Jelena

    2012-01-01

    Affective learner factors were first considered as a cause of success in language learning. This was followed by a change in approach and recently authors (e.g., Edelenbos, Johnstone, & Kubanek, 2006) have considered them an important outcome, especially in early foreign language learning (FLL). Current research into affective learner factors…

  17. Dentition and tooth replacement pattern in Chalcides (Squamata; Scincidae).

    Science.gov (United States)

    Delgado, Sidney; Davit-Beal, Tiphaine; Sire, Jean-Yves

    2003-05-01

    This study was undertaken as a prerequisite to investigations on tooth differentiation in a squamate, the Canarian scincid Chalcides. Our main goal was to determine whether the pattern of tooth replacement, known to be regular in lizards, could be helpful to predict accurately any stage of tooth development. A growth series of 20 laboratory-reared specimens, aged from 0.5 month after birth to about 6 years, was used. The dentition (functional and replacement teeth) was studied from radiographs of jaw quadrants. The number of tooth positions, the tooth number in relation to age and to seasons, and the size of the replacement teeth were recorded. In Chalcides, a single row of pleurodont functional teeth lies at the labial margin of the dentary, premaxillary, and maxillary. Whatever the age of the specimens, 16 tooth positions were recorded, on average, in each quadrant, suggesting that positions are maintained throughout life. Replacement teeth were numerous whatever the age and season, while the number of functional teeth was subject to variation. Symmetry of tooth development was evaluated by comparing teeth two by two from the opposite side in the four jaw quadrants of several specimens. Although the relative size of some replacement teeth fitted perfectly, the symmetry criterion was not reliable to predict the developmental stage of the opposite tooth, whether the pair of teeth compared was left-right or upper-lower. The best fit was found when comparing the size of successive replacement teeth from the front to the back of the jaw. Every replacement tooth that is 40-80% of its definitive size is followed, in the next position on the arcade, by a tooth that is, on average, 20% less developed. Considering teeth in alternate positions (even and odd series), each replacement tooth was a little more developed than the previous, more anterior, one (0.5-20% when the teeth are from 10-40% of their final size). The latter pattern showed that tooth replacement occurred in

  18. 3D Simulation Modeling of the Tooth Wear Process.

    Directory of Open Access Journals (Sweden)

    Ning Dai

    Full Text Available Severe tooth wear is the most common non-caries dental disease, and it can seriously affect oral health. Studying the tooth wear process is time-consuming and difficult, and technological tools are frequently lacking. This paper presents a novel method of digital simulation modeling that represents a new way to study tooth wear. First, a feature extraction algorithm is used to obtain anatomical feature points of the tooth without attrition. Second, after the alignment of non-attrition areas, the initial homogeneous surface is generated by means of the RBF (Radial Basic Function implicit surface and then deformed to the final homogeneous by the contraction and bounding algorithm. Finally, the method of bilinear interpolation based on Laplacian coordinates between tooth with attrition and without attrition is used to inversely reconstruct the sequence of changes of the 3D tooth morphology during gradual tooth wear process. This method can also be used to generate a process simulation of nonlinear tooth wear by means of fitting an attrition curve to the statistical data of attrition index in a certain region. The effectiveness and efficiency of the attrition simulation algorithm are verified through experimental simulation.

  19. Defining disability: development and validation of a mobility-Disability Severity Index (mDSI) in Charcot-Marie-tooth disease.

    Science.gov (United States)

    Ramchandren, Sindhu; Shy, Michael; Feldman, Eva; Carlos, Ruth; Siskind, Carly

    2015-06-01

    To develop and validate a reliable patient-reported scale that grades the severity of disability in Charcot-Marie-tooth disease (CMT), from an in-depth analysis of patient and healthcare provider perspectives on what mobility changes constitutes mild, moderate and severe disability. In this prospective, cross-sectional study, a 19-item Disability Questionnaire was developed following literature and expert review. Between 2011 and 2012, the Disability Questionnaire was provided to healthcare providers experienced in CMT attending national scientific meetings, and to patients self-registered with the Inherited Neuropathy Consortium--Rare Diseases Clinical Research Consortium on-line contact registry. Provider and patient responses were compared utilising a two-sided unpaired t test with Bonferroni correction. The questionnaire was then assessed for validity, reliability and unidimensionality. We analysed 259 Disability Questionnaires (167 patients, 92 providers); these showed perfect agreement between patient and provider responses on qualitative descriptions of disability, but significant differences in quantitative responses on items corresponding to minimal or severe disability (p<0.001). Validity and test-retest reliability of the questionnaire was excellent (Cronbach's α=0.96; intraclass correlation coefficients (ICC)=0.977 (0.951 to 0.993). Exploratory factor analysis and the Mokken Scaling Procedure supported the unidimensionality of the mobility-Disability Severity Index. The mobility-Disability Severity Index is a unique instrument, categorising disability from the patient's perspective, and will undergo further cross-validation studies in CMT. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  20. "ToothPIC": An Interactive Application for Teaching Oral Anatomy

    Science.gov (United States)

    Javaid, Maria; Ashrafi, Seema; Zefran, Mil; Steinberg, Arnold D.

    2016-01-01

    This paper describes the development and evaluation of an interactive educational program, "Tooth" "P"lacement and "I"dentification "C"oach ("ToothPIC"). The program uses a game-based learning paradigm and 3D visualization techniques to allow first year dentistry and hygiene students to get…

  1. Dynamics of learner affective development in early FLL

    Directory of Open Access Journals (Sweden)

    Jelena Mihaljević Djigunović

    2012-10-01

    Full Text Available Affective learner factors were first considered as a cause of success in language learning. This was followed by a change in approach and recently authors (e.g., Edelenbos, Johnstone, & Kubanek, 2006 have considered them an important outcome, especially in early foreign language learning (FLL. Current research into affective learner factors in early FLL tries to catch the developmental aspects too, and studies are emerging that take a contextual view as well. This paper describes a study on affective characteristics of young FL learners that combines the developmental and contextual perspectives. Using the case study methodology the author analyses the affective profiles of three young learners of English as a foreign language who were followed for 4 years. The analyses are done taking into account their immediate language learning environment, home support, out-of-school exposure to English and language achievement. The findings suggest that affective learner factors contribute to the dynamic complexity of early FLL.

  2. Cracked tooth syndrome. Part 2: restorative options for the management of cracked tooth syndrome.

    Science.gov (United States)

    Banerji, S; Mehta, S B; Millar, B J

    2010-06-01

    The second of this two part series on 'cracked tooth syndrome' will focus on the available methods for the immediate, intermediate and definitive management of patients affected by this condition. Included in this article is a comprehensive account of the relative merits/drawbacks of various restorative materials and their respective techniques of application for the treatment of symptomatic, incompletely fractured posterior teeth.

  3. The influence of electrospun fibre scaffold orientation and nano-hydroxyapatite content on the development of tooth bud stem cells in vitro

    NARCIS (Netherlands)

    Manen, E.H. van; Zhang, W.; Walboomers, X.F.; Vazquez, B.; Yang, F.; Ji, W.; Yu, N.; Spear, D.J.; Jansen, J.A.; Yelick, P.C.

    2014-01-01

    In stem cell-based dental tissue engineering, the goal is to create tooth-like structures using scaffold materials to guide the dental stem cells. In this study, the effect of fiber alignment and hydroxyapatite content in biodegradable electrospun PLGA scaffolds have been investigated. Fiber

  4. Cracked tooth syndrome

    OpenAIRE

    Maria Tanumihardja

    2009-01-01

    Cracked tooth syndrome is usually found in daily dental practice. The incidence of cracks teeth tends to increasing. People are living longer and keeping their teeth longer. As a consequence, people have more complex restoration and endodontic treatment, leaving teeth more prone to cracks. In addition, stressful lives may provoke unconscious habits such as clenching and bruxism which can induce cracks in teeth. However, many cracks teeth can be saved nowadays when the character...

  5. A cross-sectional analysis of the prevalence of tooth agenesis and structural dental anomalies in association with cleft type in non-syndromic oral cleft patients.

    Science.gov (United States)

    Konstantonis, Dimitrios; Alexandropoulos, Alexandros; Konstantoni, Nikoleta; Nassika, Maria

    2017-12-01

    The aim of this study was to investigate the prevalence of tooth agenesis, microdontia, and tooth malformation among non-syndromic oral cleft patients and their potential association with cleft type and gender. Intraoral records and radiographs of 154 patients (97 males and 57 females) were examined. The variables assessed were tooth agenesis, microdontia, dental malformations, and cleft types. The statistics included chi-square and Fisher's exact tests as well as logistic regression to assess any mutual effects of gender and cleft type on the dental variables. Tooth agenesis occurred in 50% of the sample and microdontia in 18%. Non-statistically significant odds ratios for the association of gender and cleft type with tooth agenesis were obtained. Tooth agenesis was substantially higher at the unilateral right CL + P and the bilateral CL + P in quadrant 1 and at the unilateral left CL + P and bilateral CL + P in quadrant 2. It was also higher, at the isolated cleft palate (CP) in quadrants 3 and 4. These results were attributed to teeth 22 (31.8%) and 12 (21.6%) in the maxilla and to teeth 35 (6.1%) and 45 (5.4%) in the mandible. In unilateral CL + P patients, the cleft quadrant that presented tooth agenesis was associated with the side of the cleft. Interdisciplinary treatment of the oral cleft patients should take into consideration the high prevalence of tooth agenesis and their association with the different cleft types. The most frequently affected teeth by cleft are by far the upper lateral incisors. Results indicate that tooth agenesis appears to be a genetically controlled anomaly related to the orofacial cleft development through various genetic links and not caused by the cleft disruptive process.

  6. A cross-sectional analysis of the prevalence of tooth agenesis and structural dental anomalies in association with cleft type in non-syndromic oral cleft patients

    Directory of Open Access Journals (Sweden)

    Dimitrios Konstantonis

    2017-06-01

    Full Text Available Abstract Background The aim of this study was to investigate the prevalence of tooth agenesis, microdontia, and tooth malformation among non-syndromic oral cleft patients and their potential association with cleft type and gender. Methods Intraoral records and radiographs of 154 patients (97 males and 57 females were examined. The variables assessed were tooth agenesis, microdontia, dental malformations, and cleft types. The statistics included chi-square and Fisher’s exact tests as well as logistic regression to assess any mutual effects of gender and cleft type on the dental variables. Results Tooth agenesis occurred in 50% of the sample and microdontia in 18%. Non-statistically significant odds ratios for the association of gender and cleft type with tooth agenesis were obtained. Tooth agenesis was substantially higher at the unilateral right CL + P and the bilateral CL + P in quadrant 1 and at the unilateral left CL + P and bilateral CL + P in quadrant 2. It was also higher, at the isolated cleft palate (CP in quadrants 3 and 4. These results were attributed to teeth 22 (31.8% and 12 (21.6% in the maxilla and to teeth 35 (6.1% and 45 (5.4% in the mandible. In unilateral CL + P patients, the cleft quadrant that presented tooth agenesis was associated with the side of the cleft. Conclusions Interdisciplinary treatment of the oral cleft patients should take into consideration the high prevalence of tooth agenesis and their association with the different cleft types. The most frequently affected teeth by cleft are by far the upper lateral incisors. Results indicate that tooth agenesis appears to be a genetically controlled anomaly related to the orofacial cleft development through various genetic links and not caused by the cleft disruptive process.

  7. Whole-Exome Sequencing Identifies Novel Variants for Tooth Agenesis.

    Science.gov (United States)

    Dinckan, N; Du, R; Petty, L E; Coban-Akdemir, Z; Jhangiani, S N; Paine, I; Baugh, E H; Erdem, A P; Kayserili, H; Doddapaneni, H; Hu, J; Muzny, D M; Boerwinkle, E; Gibbs, R A; Lupski, J R; Uyguner, Z O; Below, J E; Letra, A

    2018-01-01

    Tooth agenesis is a common craniofacial abnormality in humans and represents failure to develop 1 or more permanent teeth. Tooth agenesis is complex, and variations in about a dozen genes have been reported as contributing to the etiology. Here, we combined whole-exome sequencing, array-based genotyping, and linkage analysis to identify putative pathogenic variants in candidate disease genes for tooth agenesis in 10 multiplex Turkish families. Novel homozygous and heterozygous variants in LRP6, DKK1, LAMA3, and COL17A1 genes, as well as known variants in WNT10A, were identified as likely pathogenic in isolated tooth agenesis. Novel variants in KREMEN1 were identified as likely pathogenic in 2 families with suspected syndromic tooth agenesis. Variants in more than 1 gene were identified segregating with tooth agenesis in 2 families, suggesting oligogenic inheritance. Structural modeling of missense variants suggests deleterious effects to the encoded proteins. Functional analysis of an indel variant (c.3607+3_6del) in LRP6 suggested that the predicted resulting mRNA is subject to nonsense-mediated decay. Our results support a major role for WNT pathways genes in the etiology of tooth agenesis while revealing new candidate genes. Moreover, oligogenic cosegregation was suggestive for complex inheritance and potentially complex gene product interactions during development, contributing to improved understanding of the genetic etiology of familial tooth agenesis.

  8. Development and Validation of the Temperament and Affectivity Inventory (TAI).

    Science.gov (United States)

    Watson, David; Stasik, Sara M; Chmielewski, Michael; Naragon-Gainey, Kristin

    2015-10-01

    Trait affect scales have been a mainstay of the assessment literature for more than 50 years. These scales have demonstrated impressive construct validity, including substantial relations with personality, satisfaction, and psychopathology. However, the accumulating evidence has exposed several limitations, including (a) problems associated with retrospective biases, (b) lower temporal stability because of enhanced susceptibility to transient error, and (c) reduced self-other agreement. These limitations motivated the creation of the Temperament and Affectivity Inventory (TAI), which uses a traditional personality format (i.e., full sentences rather than single words or short phrases). The 12 TAI scales were created based on factor analyses in two samples and validated in four additional samples. The scales are internally consistent, highly stable over time, and show strong convergent, discriminant, and incremental validity in relation to self-report and interview-based measures of personality and psychopathology. Thus, the TAI provides a promising new approach to assessing trait affectivity. © The Author(s) 2014.

  9. A Quantitative Study of Hunter-Schreger Brands in the Tooth Enamel of Camelus Dromedarius

    OpenAIRE

    Radhi, Ameera

    2017-01-01

    Introduction: Hunter-Schreger Bands (HSBs) are an optical phenomenon seen in mammalian tooth enamel related to orientation changes in the enamel prisms. HSBs are considered a factor in the development and progress of certain clinical conditions, including tooth wear, the resistance of enamel to fracture, cracked tooth syndrome, enamel bonding, abfraction, and vital tooth bleaching. They can also be used for personal identification in automated systems. No previous investigations have descr...

  10. Effect of endodontic sealers on tooth color.

    Science.gov (United States)

    Meincke, Débora Könzgen; Prado, Maíra; Gomes, Brenda Paula Figueiredo; Bona, Alvaro Della; Sousa, Ezilmara Leonor Rolim

    2013-08-01

    One of the goals of endodontic treatment is the adequate filling of the root canal,which is often done using gutta-percha and sealer. It has been reported that sealer remnants in the coronary pulp chamber cause tooth color changes. Therefore, this study was designed to examine the effect of endodontic sealer remnants on tooth color, testing the hypothesis that sealers cause coronal color changes. Forty single-rooted human teeth were endodontically treated leaving excess sealer material in the coronary pulp chamber. The specimens were divided into four groups (n = 10) according to the endodontic sealer used (AH, AH Plus; EF, Endofill; EN,endome´ thasoneN; and S26, Sealer 26). Teeth were stored at 37 8C moist environment.Color coordinates (L*a*b*) were measured with a spectrophotometer before endodontic treatment(baseline-control), 24 h and 6 months after treatment. L*a*b* values were used to calculate color changes (DE). Data were statistically analyzed using Kruskal–Wallis and Mann–Whitney-U tests. Color changes were observed for all groups with S26 and EN producing the greatest mean DE values after 6 months. Endodontic sealer remnants affect tooth color confirming the experimental hypothesis. This study examined the effect of endodontic sealer remnants on tooth color, and observed that after 6 months, the sealers produced unacceptable color changes. 2012 Elsevier Ltd. All rights reserved.

  11. Death in the life of a tooth

    Czech Academy of Sciences Publication Activity Database

    Matalová, Eva; Tucker, A. S.; Sharpe, P. T.

    2004-01-01

    Roč. 83, č. 1 (2004), s. 11-16 ISSN 0022-0345 R&D Projects: GA ČR GP204/02/P112 Institutional research plan: CEZ:AV0Z5045916 Keywords : apoptosis * tooth development Subject RIV: EA - Cell Biology Impact factor: 3.131, year: 2004

  12. Early-life environmental variation affects intestinal microbiota and immune development in new-born piglets

    NARCIS (Netherlands)

    Schokker, D.J.; Zhang, J.; Zhang, L.L.; Vastenhouw, S.A.; Heilig, H.G.H.J.; Smidt, H.; Rebel, J.M.J.; Smits, M.A.

    2014-01-01

    Background - Early-life environmental variation affects gut microbial colonization and immune competence development; however, the timin Early-life environmental variation affects gut microbial colonization and immune competence development; however, the timing and additional specifics of these

  13. Impaired tooth eruption: a review.

    Science.gov (United States)

    Noffke, C E E; Chabikuli, N J; Nzima, N

    2005-11-01

    Eruption is the continuous process of movement of a tooth from its developmental location inside the jaw to its functional location in the mouth. Impaired tooth eruption, where this process is disturbed, is common in dental practice. It may manifest either as delayed or complete absence of eruption. Although unerupted teeth are usually asymptomatic, they may cause cosmetic and pathologic complications. The purpose of this article is to provide a review on the pathogenesis and differential radiographic interpretation of impaired tooth eruption.

  14. 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.

  15. [Additional skeletal elements in the nasal skull structure of Phocoena phocoena and the development of the nasal region in toothed whales].

    Science.gov (United States)

    Klima, M; van Bree, P J

    1985-01-01

    Small nasal ossicles, occasionally occurring on the caudal border of the premaxillary bones in Phocoena and some other toothed whales (Odontoceti) up to now, were considered the remnants of maxilloturbinalia. The latter, however, originate from the cartilaginous lateral wall of the embryonal nasal capsule, whereas the ossicles mentioned are remnants of the nasal floor cartilages. These additional nasal structures are homologous with the lamina transversalis anterior, and also contain the material of the cartilago paraseptalis. In comparison with the quadrupedal terrestrial mammals, the skull of odontocetes shows some important differences in development. In the nasal region, the nasal tract is shifted backward from the top of the snout to the vertex of the head, while the bony rostrum projects far forward. These changes can already be observed during the early morphogenesis of skull. We have examined embryos of Phocoena, Lagenorhynchus, and Monodon, 16 different developmental stages altogether, representing the most complete material ever examined for this purpose. There is a marked developmental trend from a complicated nasal capsule, consisting of many isolated cartilages, to a simple reduced structure, being composed of some fused cartilages only. Whereas Monodon, Lagenorhynchus, and Globicephala still possess some of the original ancestral features, common to all mammals, Phocoena in this respect is the most advanced odontocete which has been investigated so far. In Phocoena, the tectum nasi and the lateral wall of the nasal capsule are widely reconstructed in embryonal life, turned upright and displaced caudally; thus it lies immediately in front of neurocranium. The floor of the original nasal capsule persists in 2 elements only, the lamina transversalis anterior and the paraseptal cartilage, both largely fusing with each other and losing their connection with the lateral nasal wall. During early morphogenesis they move to the top of the head, expanding along

  16. [Tooth eruption disturbances and syndromes].

    Science.gov (United States)

    Oosterkamp, B C M; Ockeloen, C W; Carels, C E L; Kuijpers-Jagtman, A M

    2014-04-01

    In the tooth eruption mechanism, various disturbances can appear as a result of gene mutations, a consequence of which can be that tooth eruption does not occur. There are 5 syndromes which involve the complete failure of several or even all teeth to erupt, specifically: cleidocranial dysplasia, Gardner's syndrome, osteopetrosis, mucopolysaccharidosis and GAPO syndrome. Some are very rare and will seldom be encountered in a dental practice, but they show how vulnerable the tooth eruption mechanism is. Dentists are generally the ones who identify a tooth eruption problem in a patient. Since syndromes can be associated with other disorders, additional investigation by a clinical geneticist is always important when a syndrome is suspected.

  17. Concrescence of teeth: cemental union between the crown of an impacted tooth and the roots of an erupted tooth.

    Science.gov (United States)

    Sugiyama, Masaru; Ogawa, Ikuko; Suei, Yoshikazu; Tohmori, Hidetoshi; Higashikawa, Koichiro; Kamata, Nobuyuki

    2007-01-01

    Concrescence of teeth is a condition showing a union of adjacent teeth by only cementum. In all the previously reported cases, the union has been observed between the roots of the affected teeth. Here, we describe the first case that showed a concrescence of the crown of an impacted tooth and the roots of the erupted tooth. In addition, we discuss how this condition, especially the deposition of acellular cementum on the crown, occurred.

  18. Tooth wear and associated risk factors in a sample of Australian primary school children.

    Science.gov (United States)

    Fung, A; Brearley Messer, L

    2013-06-01

    Anecdotally, tooth wear is increasing, perhaps attributable to diet. The irreversible surface loss may result in sensitivity and loss of form and function. Little data exist on the prevalence of tooth wear in Australian children. This study investigated consumption of potentially erosive foods and drinks, examining the prevalence, distribution of tooth wear and associations in a sample of children. Parents of 350, 6-12-year-olds reported their child's oral hygiene, dietary intake, medical and dental histories; 154 children (subsample) were examined. Associations were studied with single and multivariable analyses. Tooth wear was parentally reported for 17% (59 children of the study population) and observed in 66% (102 of the subsample), particularly affecting primary teeth. Significant risk factors for parentally reported tooth wear were: consuming 2-4 cups soft drink/day (OR = 9.52), citrus flavoured sweets/gums ≥1/day (5.10), citrus fruits 1-2/wk (4.28); tooth grinding (5.32); medical condition present (2.48); male gender (2.80). Drinking 2-4 cups fruit juice/day was a significant risk factor for both parentally reported (3.23) and observed tooth wear (3.97). Tooth wear appeared under-reported as some parents were unaware their child's teeth were affected. Significant risk factors for tooth wear were identifiable from children's histories. Risk factors should be addressed early so that tooth wear in the primary dentition does not affect permanent teeth. © 2013 Australian Dental Association.

  19. A study of prevalence and distribution of tooth agenesis.

    Science.gov (United States)

    Bozga, A; Stanciu, R P; Mănuc, D

    2014-01-01

    Tooth agenesis is a phenomenon that occurs relatively commonly. The incidence of the missing teeth presented in the previous reports varies according to the studied population. The aim of this study was to find the prevalence of tooth agenesis in a population group in Bucharest. The prevalence and distribution of dental agenesis was determined in a sample of 518 patients, 285 females and 233 males, aged 6 to 41 years, who had been treated in the Clinic of Orthodontics and Dentofacial Orthopedics in Bucharest. The tooth agenesis was diagnosed by using the orthodontic records and study casts for each patient. 35 of the patients, 17 males and 18 females, were diagnosed with at least one absent permanent tooth and 47 missing permanent teeth were reported. A prevalence of 6.757% was observed for tooth agenesis. The mandibular second premolar was found to be the most affected tooth, followed by the maxillary lateral incisor, maxillary second premolar, mandibular central incisors, mandibular second molar and mandibular lateral incisor. The incidence of dental agenesis, its pattern and distribution per tooth type are in accordance with the previous published studies.

  20. Postnatal mandibular cheek tooth development in the miniature pig based on two-dimensional and three-dimensional X-ray analyses.

    Science.gov (United States)

    Ide, Yoshiaki; Nakahara, Taka; Nasu, Masanori; Matsunaga, Satoru; Iwanaga, Takehiro; Tominaga, Noriko; Tamaki, Yuichi

    2013-08-01

    The miniature pig is a useful large laboratory animal model. Various tissues and organs of miniature pigs are similar to those of humans in terms of developmental, anatomical, immunological, and physiological characteristics. The oral and maxillofacial region of miniature pigs is often used in preclinical studies of regenerative dentistry. However, there is limited information on the dentition and tooth structure of miniature pigs. The purpose of this study was to examine the time-course changes of dentition and tooth structure (especially the root) of the miniature pig mandibular cheek teeth through X-ray analyses using soft X-ray for two-dimensional observations and micro-CT for three-dimensional observations. The mandibles of male Clawn strain miniature pigs (2 weeks and 3, 5, 7, 9, 11, 14, 17, and 29 months of age) were used. X-ray analysis of the dentition of miniature pig cheek teeth showed that the eruption pattern of the miniature pig is diphyodont and that the replacement pattern is vertical. Previous definitions of deciduous and permanent teeth often varied and there has been no consensus on the number of teeth (dentition); however, we found that three molars are present in the deciduous dentition and that four premolars and three molars are present in the permanent dentition. Furthermore, we confirmed the number of tooth roots and root canals. We believe that these findings will be highly useful in future studies using miniature pig teeth. Copyright © 2013 Wiley Periodicals, Inc.

  1. Autogenous tooth transplantation: an alternative to replace extracted tooth

    Directory of Open Access Journals (Sweden)

    David B. Kamadjaja

    2015-09-01

    Full Text Available Background: The gold standard treatment to replace missing tooth is dental implants, however, in certain cases, such as in young patients its placement is contraindicated. Autogenous tooth transplantation, which has been widely done in Scandinavian countries for many years, may become a good alternative to overcome this problem. Purpose: This article attempted to provide information about the indication, treatment planning, surgical technique and the successful result of autogenous tooth transplantation. Case: A fifteen year old male patient presented with large caries and periapical disease of his lower left first molar, which was partially erupted and the roots was not fully formed in radiograph. Case management: Autogenous tooth transplantation procedure was performed consisting of extraction of #36, odontectomy of #38 followed by its implantation to socket #36 and fixation of the transplanted tooth to the adjacent teeth. Post operative evaluation was done on regular basis within 18 months period. There was no complaint, the tooth was clinically stable and no evidence of periodontal problem. Serial radiographs showed healing of alveolar bone and periodontal tissue, and the complete root formation was evident by 18 months post operatively. Conclusion: Autogenous tooth transplantation is a potential alternative to replace extracted tooth. Provided that the case be properly planned and operation carefully performed, successful result of this treatment can be achieved.

  2. Effects of tooth profile modification on dynamic responses of a high speed gear-rotor-bearing system

    Science.gov (United States)

    Hu, Zehua; Tang, Jinyuan; Zhong, Jue; Chen, Siyu; Yan, Haiyan

    2016-08-01

    A finite element node dynamic model of a high speed gear-rotor-bearing system considering the time-varying mesh stiffness, backlash, gyroscopic effect and transmission error excitation is developed. Different tooth profile modifications are introduced into the gear pair and corresponding time-varying mesh stiffness curves are obtained. Effects of the tooth profile modification on mesh stiffness are analyzed, and the natural frequencies and mode shapes of the gear-rotor-bearing transmission system are given. The dynamic responses with respect to a wide input speed region including dynamic factor, vibration amplitude near the bearing and dynamic transmission error are obtained by introducing the time-varying mesh stiffness in different tooth profile modification cases into the gear-rotor-bearing dynamic system. Effects of the tooth profile modification on the dynamic responses are studied in detail. The numerical simulation results show that both the short profile modification and the long profile modification can affect the mutation of the mesh stiffness when the number of engaging tooth pairs changes. A short profile modification with an appropriate modification amount can improve the dynamic property of the system in certain work condition.

  3. Do economic policy decisions affect stock market development in ...

    African Journals Online (AJOL)

    The paper finds government revenue and exchange rate reduce stock market development. A policy mix identified was that, the outcomes of government expenditure and government borrowing interest rate exert no influence on stock market development. For equity investors not to easily transfer their investments in ...

  4. UX concepts, how they affected our development flow.

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    The talk aims at showing the development of Locations before and after this moment, and how the way of thinking at the application changed for taking in account the improvements in the user experience of the application.

  5. Factors affecting the development of in vitro fertilization in camelids

    Directory of Open Access Journals (Sweden)

    Trasorras VL

    2016-12-01

    Full Text Available In any program of in vitro embryo production, the ultimate goal is to develop high quality embryos being able to get a normal pregnancy and finally resulting in the birth of a healthy offspring, goal not reach yet in camelids. The application of assisted reproductive techniques, such as in vitro fertilization and subsequent in vitro embryo culture, can extend the knowledge of early embryonic development and make possible the increase of the population of genetically superior animals.

  6. Angulation change of the third molar tooth in orthodontic treatment

    Directory of Open Access Journals (Sweden)

    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.

  7. The use of an individual jig in measuring tooth length changes.

    Science.gov (United States)

    Brezniak, Naphtali; Goren, Shay; Zoizner, Ronen; Dinbar, Ariel; Arad, Arnon; Wasserstein, Atalia; Heller, Moshe

    2004-12-01

    The parallel periapical radiographic technique hides several problems that might affect the image seen on the film. To overcome these problems a special jig with an external wire attached to the tooth surface and parallel to its long axis was suggested. This study examines the accuracy of using an external object for measuring root length differences due to angular changes between the tooth and the film. The rule of three was used for all calculations as a compensating formula. A human central incisor was placed in a special jig. Two different wire lengths (11.8 +/- 0.1 mm and 16 +/- 0.1 mm) were attached to the tooth in six different ways. The tooth was radiographed at four different film to tooth angulations. The tooth and wire lengths were measured on the model itself and directly on the scanned film on a computer monitor. The results reveal that a wire, placed nine mm from the crown and parallel to the long axis of the tooth was the best jig for accurately measuring tooth length changes. Neither palatal nor buccal metal wires, intimately attached to the crown of the tooth, can serve as a tool to measure tooth length changes. The study could not find a way to skip the need for a cephalometric radiograph to verify the parallelism between the wire and the long axis of the tooth for this matter.

  8. [Tooth eruption disturbances and syndromes

    NARCIS (Netherlands)

    Oosterkamp, B.A.M. van; Ockeloen, C.W.; Carels, C.E.L.; Kuijpers-Jagtman, A.M.

    2014-01-01

    In the tooth eruption mechanism, various disturbances can appear as a result of gene mutations, a consequence of which can be that tooth eruption does not occur. There are 5 syndromes which involve the complete failure of several or even all teeth to erupt, specifically: cleidocranial dysplasia,

  9. Broken or knocked out tooth

    Science.gov (United States)

    ... Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Broken or knocked out tooth URL of this page: // ... and fluid solution. Consider buying 1 for your home first aid kit . Also ... If your tooth is badly broken, your nerve endings may be exposed. You will ...

  10. A novel family of small proteins that affect plant development

    Energy Technology Data Exchange (ETDEWEB)

    John Charles Walker

    2011-04-29

    The DVL genes represent a new group of plant proteins that influence plant growth and development. Overexpression of DVL1, and other members of the DVL family, causes striking phenotypic changes. The DVL proteins share sequence homology in their C-terminal half. Point mutations in the C-terminal domain show it is necessary and deletion studies demonstrate the C-terminal domain is sufficient to confer the overexpression phenotypes. The phenotypes observed, and the conservation of the protein sequence in the plant kingdom, does suggest the DVL proteins have a role in modulating plant growth and development. Our working hypothesis is the DVL proteins function as regulators of cellular signaling pathways that control growth and development.

  11. [Inequity in health affects the development in Peru].

    Science.gov (United States)

    Sánchez-Moreno, Francisco

    2013-01-01

    Unfair and avoidable differences in exercising the right to health coexist with the Universal Declaration of Human Rights since 1948. Some causes of the persistent inequality inferred after Alma-Ata are insufficient funding, development of national health systems without adequate prioritization, and since the 80s with economic consensus to introduce the health market model. Health in Peru is still an area of little progress, ostensible inequality and limited participation in development. Policies in the 20th century are still insufficient; and missing opportunities like increasing the value of exports over a decade ago is a recurring issue. For a health reform to be successful in terms of equality and development, it is necessary to agree on a state policy, establish a modern and equitable social security funding system and eradicate the inconsistencies in the national health system.

  12. Relationship between gestational age, birth weight and deciduous tooth eruption

    Directory of Open Access Journals (Sweden)

    Afrin Mohamed Khalifa

    2014-06-01

    Conclusion: Delayed tooth eruption was related to lower birth weight and prematurity. The delayed eruption in preterm babies may be related to premature birth and not to a delay in dental development.

  13. Enhanced Prediction of Gear Tooth Surface Fatigue Life, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Sentient will develop an enhanced prediction of gear tooth surface fatigue life with rigorous analysis of the tribological phenomena that contribute to pitting...

  14. Do international economic developments affect the South African economy?

    Directory of Open Access Journals (Sweden)

    JA Swanepoel

    2014-07-01

    Full Text Available Globalisation has opened economies more, exposing them to more international shocks and increasing the challenges to which domestic economic policies must respond. This paper provides a starting point for the analysis of the impact of international economic developments on the South African economy by means of graphical illustrations, correlations coefficients and in some cases a VAR analysis. Although this paper has shed some light on the importance of international economic developments on the South African economy, more rigorous econometric investigation is needed to validate the arguments and to address many of the unresolved questions.

  15. Functional Tooth Regeneration Using a Bioengineered Tooth Unit as a Mature Organ Replacement Regenerative Therapy

    Science.gov (United States)

    Imamura, Aya; Ogawa, Miho; Yasukawa, Masato; Yamazaki, Hiromichi; Morita, Ritsuko; Ikeda, Etsuko; Nakao, Kazuhisa; Takano-Yamamoto, Teruko; Kasugai, Shohei; Saito, Masahiro; Tsuji, Takashi

    2011-01-01

    Donor organ transplantation is currently an essential therapeutic approach to the replacement of a dysfunctional organ as a result of disease, injury or aging in vivo. Recent progress in the area of regenerative therapy has the potential to lead to bioengineered mature organ replacement in the future. In this proof of concept study, we here report a further development in this regard in which a bioengineered tooth unit comprising mature tooth, periodontal ligament and alveolar bone, was successfully transplanted into a properly-sized bony hole in the alveolar bone through bone integration by recipient bone remodeling in a murine transplantation model system. The bioengineered tooth unit restored enough the alveolar bone in a vertical direction into an extensive bone defect of murine lower jaw. Engrafted bioengineered tooth displayed physiological tooth functions such as mastication, periodontal ligament function for bone remodeling and responsiveness to noxious stimulations. This study thus represents a substantial advance and demonstrates the real potential for bioengineered mature organ replacement as a next generation regenerative therapy. PMID:21765896

  16. Does bank ownership affect relationship lending: A developing country perspective

    Directory of Open Access Journals (Sweden)

    Ashiqur Rahman

    2017-05-01

    Full Text Available In this paper we aim to explore how the type of bank ownership - local private banks, government-owned banks (public banks and foreign banks - can affect relationship lending to small and medium enterprises (SMEs by using a unique data set from Bangladeshi banking sector. We found that private banks differ from government-owned and foreign banks in terms of relationship lending and credit facilities to SMEs. More specifically, our results suggest that unlike government and foreign banks, private banks do consider soft information from relationship lending while setting up the loan spread to SMEs. We can also confirm that exclusive banking relationship or repeated banking with private banks can soften credit conditions (loan maturity and covenants. Moreover, we found empirical evidence that banking relationship is important for private banks in terms of SME credit risk evaluation. Finally, as according to our expectation, the results confirm that regardless of prior relationship, private banks are more depended on collateral-based lending to SMEs than government-owned or foreign banks.

  17. Traumatic Experience in Infancy: How Responses to Stress Affect Development

    Science.gov (United States)

    Witten, Molly Romer

    2010-01-01

    Responses to traumatic stress during the earliest years of life can change quickly and can be difficult to identify because of the young child's rapid rate of development. The symptoms of traumatic stress will depend on the child's developmental level and individual coping styles, as well as the quality and nature of the child's most important…

  18. Factors affecting the success of development projects : A behavioral perspective

    NARCIS (Netherlands)

    Aga, Deribe Assefa

    2016-01-01

    This dissertation sought to examine behavioral-related critical success factors in the context of Non-Governmental Organization (NGO) sector development projects in Ethiopia. The dissertation applied both a cross-sectional survey design and an experimental design in separate settings, and it is

  19. Factors Affecting the Professional Development of Elementary English Teachers

    Science.gov (United States)

    Zein, Subhan

    2016-01-01

    The poor classroom practices of English teachers at elementary level in Indonesia have been attributed to the inadequacy of pre-service education. Yet, whether in-service professional development (PD) also plays a role is unknown. This study investigated the perspectives of 23 teachers, 14 teacher educators and 3 school principals regarding the…

  20. Plant community development is affected by nutrients and soil biota

    NARCIS (Netherlands)

    De Deyn, G.B.; Raaijmakers, C.E.; Van der Putten, W.H.

    2004-01-01

    1 Plant community development depends to a great extent on the availability of soil nutrients, but recent studies underline the role of symbiotic, herbivorous and pathogenic soil biota. We tested for interactions between these biotic and abiotic factors by studying the effects of additional

  1. Do Economic Policy Decisions affect Stock Market Development in ...

    African Journals Online (AJOL)

    For equity investors not to easily transfer their investments in response to changes in macroeconomic policies among others, the study recommends good macroeconomic management. Keywords: Stock Market Development, Macroeconomic policy, Government spending, ADRL,. Ghana, West Africa. JEL Classification: G2 ...

  2. Teaching Reading as Concept Development: Emphasis on Affective Thinking.

    Science.gov (United States)

    Henry, George H.

    The purposes of this monograph are to reveal how the language arts teacher at any level of instruction might go about the teaching of reading as concept development and to suggest that this method of teaching reading be made part of the preparation of both the reading teacher and the English teacher. The monograph is composed of two parts. Part 1,…

  3. Dental regenerative therapy: Stem cell transplantation and bioengineered tooth replacement

    Directory of Open Access Journals (Sweden)

    Kazuhisa Nakao

    2008-07-01

    Full Text Available For clinical treatment of tooth defects and tooth loss, nonbiotechnological approaches, such as the use of prostheses and implants, have generally been employed. Dental regenerative therapies which restore or replace defective teeth using autologous explants are being investigated using current understandings of developmental biology, stem cell biology, and regenerative medicine. Recently, dental tissue stem/progenitor cells, which can differentiate into dental cell lineages, have been identified in both impacted and erupted human teeth, and these cells can be used to regenerate some dental tissues. Tissue engineering using scaffold and cell aggregate methods may also be used to produce bioengineered teeth from dissociated cells for therapeutic applications of whole tooth replacement. Recent breakthroughs in single cell manipulation methods for the reconstitution of bioengineered tooth germ and the investigation of in vivo development of artificial tooth germ in the adult oral environment have been reported. These researches and developments will ultimately lead to the realization of dental regenerative therapies for partial repair by stem cell transplantation and for whole tooth replacement using bioengineered tooth germ.

  4. Hydroxyapatite coating on damaged tooth surfaces by immersion

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Byoung-Ki; Ryu, Su-Chak [Department of Nanomaterials Engineering, College of Nanoscience and Nanotechnology, Pusan National University, Miryang, 607-706 (Korea, Republic of); Sun, Fangfang; Koh, Kwangnak; Han, Dong-Wook; Lee, Jaebeom, E-mail: jaebeom@pusan.ac.k [Department of Nanomedical Engineering, College of Nanoscience and Nanotechnology, Pusan National University, Miryang, 607-706 (Korea, Republic of)

    2009-04-15

    Hydroxyapatite (HAp) was coated on scratched areas of a human tooth and HAp disks by the immersion method in a HAp colloidal solution (<=20{mu}m of average diameter dispersed in DI water). The surface morphologies of the scratched area after immersion for 1-3 months were investigated showing that the damaged surfaces were remarkably recovered. Then, the mechanical property and chemical stability of the HAp coating layers on both specimens were determined via the Vickers hardness test and concentration measurement of extracted Ca{sup 2+} ions, respectively, after strong acidic treatment. The cellular behavior of mouse calvaria-derived pre-osteoblastic cells (MC3T3-E1) was also examined on the HAp layers regenerated on micro-scratched HAp disks for the purpose of their potential applications on maxillofacial bone conservation and reconstruction for prosthetic dentistry, and artificial disk preparation of a vertebral column. The notable loss of Ca{sup 2+} ions under a highly acidic condition was not observed in the layers coated by HAp adsorption, indicating that the coating surface was well adhered with the original surfaces of the respective specimen. Moreover, the HAp adsorption did not adversely affect the adhesion, growth and proliferation of MC3T3-E1 cells on the coated HAp layers for up to 21 days. These results suggest that the HAp coating on the scratched areas of the tooth would be effectively applicable for the development of long-term prevention of micro-cleavage and tooth health supporters to reduce discoloration and further maxillofacial and orthopedic applications.

  5. FACTORS AFFECTING THE DEVELOPMENT OF MEDICAL TOURISM IN PUBLIC HOSPITALS

    OpenAIRE

    YİĞİT, Vahit

    2016-01-01

    Medical tourism is a burgeoning industry in the world. Nowadays, over 50countries have been identified medical tourism as a national industry. AlthoughAsian countries where India, Thailand, Singapore and Malaysia popular medicaltourism destination, medical tourism in Turkey has not reached the desiredlevel and and could not get enough share of the medical tourism market. The aimof this study is to determine the factors influencing the development ofmedical tourism in Turkey. This research was...

  6. Whole Genome Sequencing Reveals Novel Non-Synonymous Mutation in Ectodysplasin A (EDA) Associated with Non-Syndromic X-Linked Dominant Congenital Tooth Agenesis

    Science.gov (United States)

    Sarkar, Tanmoy; Bansal, Rajesh; Das, Parimal

    2014-01-01

    Congenital tooth agenesis in human is characterized by failure of tooth development during tooth organogenesis. 300 genes in mouse and 30 genes in human so far have been known to regulate tooth development. However, candidature of only 5 genes viz. PAX9, MSX1, AXIN2, WNT10A and EDA have been experimentally established for congenitally missing teeth like hypodontia and oligodontia. In this study an Indian family with multiple congenital tooth agenesis was identified. Pattern of inheritance was apparently autosomal dominant type with a rare possibility to be X-linked. Whole genome sequencing of two affected individuals was carried out which revealed 119 novel non-synonymous single nucleotide variations (SNVs) distributed among 117 genes. Out of these only one variation (c.956G>T) located at exon 9 of X-linked EDA gene was considered as pathogenic and validated among all the affected and unaffected family members and unrelated controls. This variation leads to p.Ser319Ile change in the TNF homology domain of EDA (transcript variant 1) protein. In silico analysis predicts that this Ser319 is well conserved across different vertebrate species and a part of putative receptor binding site. Structure based homology modeling predicts that this amino acid residue along with four other amino acid residues nearby, those when mutated known to cause selective tooth agenesis, form a cluster that may have functional significance. Taken together these results suggest that c.956G>T (p.Ser319Ile) mutation plausibly reduces the receptor binding activity of EDA leading to distinct tooth agenesis in this family. PMID:25203534

  7. Conference Reports: New developments affecting natural gas sales contracts

    International Nuclear Information System (INIS)

    1999-01-01

    Papers presented at a conference examining and reviewing recent trends in natural gas sales contracts are contained in this volume. Conference participants heard 14 presentations, with topics including pricing provisions in gas contracts, security of supply, cross-border issues, legislative reform of electronic data interchange, digital signatures, new developments in managing contracts in a competitive environment, the changing role of natural gas aggregators, drafting 'force majeure' clauses in natural gas purchase/sale contracts and the consequences and remedies for breach of natural gas contracts. The volume also includes biographical notes, and current addresses of the speakers

  8. Early development of Xenopus embryos is affected by simulated gravity

    Science.gov (United States)

    Yokota, Hiroki; Neff, Anton W.; Malacinski, George M.

    1994-01-01

    Early amphibian (Xenopus laevis) development under clinostat-simulated weightlessness and centrifuge-simulated hypergravity was studied. The results revealed significant effects on (i) 'morphological patterning' such as the cleavage furrow pattern in the vegetal hemisphere at the eight-cell stage and the shape of the dorsal lip in early gastrulae and (ii) 'the timing of embryonic events' such as the third cleavage furrow completion and the dorsal lip appearance. Substantial variations in sensitivity to simulated force fields were observed, which should be considered in interpreting spaceflight data.

  9. Older Siblings Affect Gut Microbiota Development in Early Childhood

    DEFF Research Database (Denmark)

    Laursen, Martin Frederik; Zachariassen, Gitte; Bahl, Martin Iain

    . Gut microbiota characteristics were not significantly associated with cumulative occurrence of eczema and asthmatic bronchitis during the first three years of life. Conclusions: Presence of older siblings is associated with increased gut microbial diversity and richness during early childhood, which...... could contribute to the substantiation of the hygiene hypothesis. However, no associations were found between gut microbiota and atopic symptoms of eczema and asthmatic bronchitis during early childhood and thus further studies are required to elucidate whether sibling-associated gut microbial changes...... influence development of allergies later in childhood.   The work has recently (July 2015) been accepted for publication in BMC Microbiology...

  10. Legislative framework affecting First Nations and resource development

    International Nuclear Information System (INIS)

    Maclean, M.

    1998-01-01

    In its Delgamuukw decision (released December 1997), the Supreme Court of Canada has given a clear direction to the Crown and First Nations to negotiate rather than litigate outstanding claims within the province of British Columbia. This paper describes the practical implications which the Delgamuukw decision will have for resource development on lands located within the traditional territories of Aboriginal people, reviews constitutional and jurisdictional issues, and discusses issues such as reserve lands in British Columbia, including the nature of reserve interest, tax considerations, the surrender of reserve lands, and provincial regulation on reserve lands

  11. Method for developing an optimal emergence profile using heat-polymerized provisional restorations for single-tooth implant-supported restorations.

    Science.gov (United States)

    Macintosh, Daniel C T; Sutherland, Mark

    2004-03-01

    This article describes a method for creating an improved emergence profile with single-tooth, implant-supported restorations. An easily trimmed silicone gingival substitute is used to allow polymerization of acrylic resin provisional restorations to achieve control of the emergence profile. Gingival trauma is minimized by eliminating intraoral use of monomer and minimizing surgical procedures. Provisional restorations can be assessed to ensure the contour is acceptable and the trimmed gingival substitute can be used to fabricate a similar profile in the definitive prosthesis. The provisional restorations may be used instead of standard prefabricated healing abutments to guide the healing contours of the peri-implant gingival tissue.

  12. Does bilingual experience affect early visual perceptual development?

    Science.gov (United States)

    Schonberg, Christina; Sandhofer, Catherine M.; Tsang, Tawny; Johnson, Scott P.

    2014-01-01

    Visual attention and perception develop rapidly during the first few months after birth, and these behaviors are critical components in the development of language and cognitive abilities. Here we ask how early bilingual experiences might lead to differences in visual attention and perception. Experiments 1–3 investigated the looking behavior of monolingual and bilingual infants when presented with social (Experiment 1), mixed (Experiment 2), or non-social (Experiment 3) stimuli. In each of these experiments, infants' dwell times (DT) and number of fixations to areas of interest (AOIs) were analyzed, giving a sense of where the infants looked. To examine how the infants looked at the stimuli in a more global sense, Experiment 4 combined and analyzed the saccade data collected in Experiments 1–3. There were no significant differences between monolingual and bilingual infants' DTs, AOI fixations, or saccade characteristics (specifically, frequency, and amplitude) in any of the experiments. These results suggest that monolingual and bilingual infants process their visual environments similarly, supporting the idea that the substantial cognitive differences between monolinguals and bilinguals in early childhood are more related to active vocabulary production than perception of the environment. PMID:25566116

  13. Grhl1 deficiency affects inner ear development in zebrafish.

    Science.gov (United States)

    Liu, Fei; Yang, Fan; Wen, Danping; Xia, Wenjun; Hao, Lili; Hu, JiongJiong; Zong, Jie; Shen, Xiaofang; Ma, Jing; Jiang, Nan; Sun, Shaoyang; Zhang, Jin; Wang, Huijun; Wang, Xu; Ma, Zhaoxin; Ma, Duan

    2015-01-01

    Many genes that have been found to contribute to deafness are currently being studied. Some 87 non-syndromic hereditary deafness genes have been confirmed. Proteins associated with cochlear development have also been confirmed. Some of these proteins have important relationships with gap junctions (GJ) and tight junctions (TJ). However, the desmosome junction has received little attention due to controversy over whether it could be detected in the inner ear. GRHL1 is a conserved transcriptional regulator, and it is key to vertebrate desmosome formation. GRHL2 has been confirmed as a deafness gene at the DFNA28 locus. These two homologous proteins have similar sequences and functions. Here, a grhl1 down-regulated zebrafish model exhibited inner ear developmental malformations, including missing otoliths, disordered and abnormal numbers of hair cells in the inner ear and lateral line, and sound insensitivity. The mutant zebrafish swam in circles. Hair cell apoptosis was evident. Under electron microscopy, desmosomes in the otic sensory epithelium were found to be damaged. These defects were partially rescued by treatment with either GRHL1 or its target gene, DSG1. Collectively, these data are the first to indicate that grhl1 is important to the developing inner ear epithelia in zebrafish and that it acts via desmosome junction regulation.

  14. Organizational development in Ethiopia: Factors affecting organizations’ implementation of feedback

    Directory of Open Access Journals (Sweden)

    Ariel Falconer

    2014-01-01

    Full Text Available Non-governmental organizations (NGOs receiving organizational development assistance funded and facilitated by a third party frequently receive recommendations designed to improve their overall functioning. Research suggests that tailored in-person communication of recommendations results in increased implementation of recommendations. This study assessed whether the method and frequency of communication from an outside organization influenced Ethiopian NGOs’ ability to implement organizational development recommendations. A secondary study goal was to identify additional factors that facilitated or inhibited implementation of recommendations. Twenty two NGOs were surveyed about the amount, type, and timing of communication; their perception of the value of communication in implementing recommendations; barriers to implementation; and strategies used to overcome barriers to implementation. The frequency and level of personalization of communication was not consistently associated with organizational implementation of recommendations. Receiving communication was significantly associated with an organization’s motivation (mean = 4.5 ± 0.6, understanding (mean = 4.2 ± 0.6, and ability (mean = 3.9 ± 0.6 to implement recommendations (p value = 0.02. Respondents reported that external factors, including funding; staff time, expertise, and training; information systems; leadership; and government regulations on nonprofit administrative spending, strongly influenced their ability to implement recommendations.

  15. Organizational development in Ethiopia: Factors affecting organizations’ implementation of feedback

    Directory of Open Access Journals (Sweden)

    Ariel Falconer

    2014-05-01

    Full Text Available Non-governmental organizations (NGOs receiving organizational development assistance funded and facilitated by a third party frequently receive recommendations designed to improve their overall functioning. Research suggests that tailored in-person communication of recommendations results in increased implementation of recommendations. This study assessed whether the method and frequency of communication from an outside organization influenced Ethiopian NGOs’ ability to implement organizational development recommendations. A secondary study goal was to identify additional factors that facilitated or inhibited implementation of recommendations. Twenty two NGOs were surveyed about the amount, type, and timing of communication; their perception of the value of communication in implementing recommendations; barriers to implementation; and strategies used to overcome barriers to implementation. The frequency and level of personalization of communication was not consistently associated with organizational implementation of recommendations. Receiving communication was significantly associated with an organization’s motivation (mean = 4.5 ± 0.6, understanding (mean = 4.2 ± 0.6, and ability (mean = 3.9 ± 0.6 to implement recommendations (p value = 0.02. Respondents reported that external factors, including funding; staff time, expertise, and training; information systems; leadership; and government regulations on nonprofit administrative spending, strongly influenced their ability to implement recommendations.

  16. Does vitamin C deficiency affect cognitive development and function?

    Science.gov (United States)

    Hansen, Stine Normann; Tveden-Nyborg, Pernille; Lykkesfeldt, Jens

    2014-09-19

    Vitamin C is a pivotal antioxidant in the brain and has been reported to have numerous functions, including reactive oxygen species scavenging, neuromodulation, and involvement in angiogenesis. Absence of vitamin C in the brain has been shown to be detrimental to survival in newborn SVCT2(-/-) mice and perinatal deficiency have shown to reduce hippocampal volume and neuron number and cause decreased spatial cognition in guinea pigs, suggesting that maternal vitamin C deficiency could have severe consequences for the offspring. Furthermore, vitamin C deficiency has been proposed to play a role in age-related cognitive decline and in stroke risk and severity. The present review discusses the available literature on effects of vitamin C deficiency on the developing and aging brain with particular focus on in vivo experimentation and clinical studies.

  17. Does vitamin C deficiency affect cognitive development and function?

    DEFF Research Database (Denmark)

    Hansen, Stine Normann; Tveden-Nyborg, Pernille; Lykkesfeldt, Jens

    2014-01-01

    Vitamin C is a pivotal antioxidant in the brain and has been reported to have numerous functions, including reactive oxygen species scavenging, neuromodulation, and involvement in angiogenesis. Absence of vitamin C in the brain has been shown to be detrimental to survival in newborn SVCT2(-/-) mice...... and perinatal deficiency have shown to reduce hippocampal volume and neuron number and cause decreased spatial cognition in guinea pigs, suggesting that maternal vitamin C deficiency could have severe consequences for the offspring. Furthermore, vitamin C deficiency has been proposed to play a role in age......-related cognitive decline and in stroke risk and severity. The present review discusses the available literature on effects of vitamin C deficiency on the developing and aging brain with particular focus on in vivo experimentation and clinical studies....

  18. Does Vitamin C Deficiency Affect Cognitive Development and Function?

    Directory of Open Access Journals (Sweden)

    Stine Normann Hansen

    2014-09-01

    Full Text Available Vitamin C is a pivotal antioxidant in the brain and has been reported to have numerous functions, including reactive oxygen species scavenging, neuromodulation, and involvement in angiogenesis. Absence of vitamin C in the brain has been shown to be detrimental to survival in newborn SVCT2(−/− mice and perinatal deficiency have shown to reduce hippocampal volume and neuron number and cause decreased spatial cognition in guinea pigs, suggesting that maternal vitamin C deficiency could have severe consequences for the offspring. Furthermore, vitamin C deficiency has been proposed to play a role in age-related cognitive decline and in stroke risk and severity. The present review discusses the available literature on effects of vitamin C deficiency on the developing and aging brain with particular focus on in vivo experimentation and clinical studies.

  19. Psychosocial aspect of anterior tooth discoloration among adolescents in igbo-ora, southwestern Nigeria.

    Science.gov (United States)

    Ibiyemi, O; Taiwo, J O

    2011-12-01

    Aesthetic problems in adolescence can have a significant effect on their psychosocial development. Abnormalities in tooth color can lead to such problem especially if it affects anterior teeth. This study therefore assessed the effects of anterior tooth discoloration on the psychosocial well-being of adolescents with a view to providing information that will aid the prevention and treatment of this dental problem. This study was a cross-sectional study involving 384 adolescents aged between 10 and 20years in Igboora southwestern Nigeria. Twenty-six item semi-structured questionnaire comprising variables on demographics and psychosocial effects were researcher-administered. Oral examination of the labial surfaces of the anterior permanent teeth was carried by two examiners. Frequencies and mean were generated. Chi-square and Fischer's exact tests were used to test associations between categorical variables at (P≤0.05). The mean age of participants was 14.7±2.3 years. Ninety four (24.5%) participants perceived that their anterior teeth were discolored, 65 (69.1%) of these did not like the discoloration. Sixty two (65.9%), 47 (50.0%) and 38 (40.4%) respectively reported that it prevented them from freely answering questions, smiling and interacting. After oral examination, 120 (31.2%) subjects had one form of anterior tooth discoloration. The cause of tooth discoloration in the majority 64 (16.7%) of the participants was due to extrinsic stains from compounds incorporated into plaque and calculus. Age group, sex, class of participants and presence of tetracycline stained teeth were significantly related with reported psychosocial problems (p≤0.05). About one third of adolescents had anterior tooth discoloration and the majority reported one form of psychosocial problem.

  20. Dental Fear in Children with Repeated Tooth Injuries.

    Science.gov (United States)

    Negovetić Vranić, Dubravka; Ivančić Jokić, Nataša; Bakarčić, Danko; Carek, Andreja; Rotim, Željko; Verzak, Željko

    2016-06-01

    Tooth injuries are serious clinical conditions. Some children experience dental trauma only once, while others are more prone to repeated tooth injuries. Repeated dental trauma occurs in 19.4% to 30% of patients. Pain and dental trauma are the most common reasons for fear and anxiety. The main objective of this study was to investigate how dental trauma, as well as repeated dental trauma affects the occurrence and development of dental fear in children. The study was conducted on a random sample of 147 subjects (88 boys and 59 girls) aged 5-8 and 9-12 years. Subjects in both age groups were divided into subroups without dental trauma, with one dental trauma and with repeated dental trauma. The validated Children’s Fear Survey Schedule – Dental Subscale was used on fear assessment. Results showed that only 12.2% of children without trauma, 33.3% with one trauma and 51.7% with repeated trauma were not afraid of injection. Older children had a significantly lower fear of injections, touch of an unknown person, choking, going to the hospital and people in white uniforms. Dentist was not the cause of fear in 65.5% of patients with repeated trauma. With each repeated injury of teeth, the degree of their fear of dental treatment was lower.

  1. How Ketamine Affects Livers of Pregnant Mice and Developing Mice?

    Directory of Open Access Journals (Sweden)

    Hoi Man Cheung

    2017-05-01

    Full Text Available It is well known that ketamine abuse can induce liver damage in adult addicts, but the effects of ketamine abuse in pregnant mothers on their offspring have received less attention. In this study, we investigated the effects of 5-day ketamine injections (30 mg/kg to pregnant Institute for Cancer Research (ICR mice during early gestation or mid-gestation on the aspartate aminotransferase (AST and alkaline phosphatase (ALP activities of the mothers and the offspring. We also looked into whether administering ketamine treatment to the mothers had any effects on the extent of fibrosis, cell proliferation and cell death in the livers of the newborns. No significant biochemical differences were found between treatment and control groups in the mothers. In the offspring, ketamine treatment mildly suppressed the gradual increase of hepatic AST activity in neonates during liver maturation. Measurements of hepatic ALP activity and lactic acid dehydrogenase (LDH immunoreactivity revealed that ketamine treatment may lead to increased cell death. Proliferation of liver cells of the newborns was also retarded as shown by reduced proliferative cell nuclear antigen (PCNA immunoreactivity in the ketamine groups. No obvious fibrosis was evident. Thus, we demonstrated that ketamine administration to pregnant mice suppressed hepatic development and also induced liver cell death of the offspring.

  2. How Ketamine Affects Livers of Pregnant Mice and Developing Mice?

    Science.gov (United States)

    Cheung, Hoi Man; Chow, Tony Chin Hung; Yew, David Tai Wai

    2017-05-19

    It is well known that ketamine abuse can induce liver damage in adult addicts, but the effects of ketamine abuse in pregnant mothers on their offspring have received less attention. In this study, we investigated the effects of 5-day ketamine injections (30 mg/kg) to pregnant Institute for Cancer Research (ICR) mice during early gestation or mid-gestation on the aspartate aminotransferase (AST) and alkaline phosphatase (ALP) activities of the mothers and the offspring. We also looked into whether administering ketamine treatment to the mothers had any effects on the extent of fibrosis, cell proliferation and cell death in the livers of the newborns. No significant biochemical differences were found between treatment and control groups in the mothers. In the offspring, ketamine treatment mildly suppressed the gradual increase of hepatic AST activity in neonates during liver maturation. Measurements of hepatic ALP activity and lactic acid dehydrogenase (LDH) immunoreactivity revealed that ketamine treatment may lead to increased cell death. Proliferation of liver cells of the newborns was also retarded as shown by reduced proliferative cell nuclear antigen (PCNA) immunoreactivity in the ketamine groups. No obvious fibrosis was evident. Thus, we demonstrated that ketamine administration to pregnant mice suppressed hepatic development and also induced liver cell death of the offspring.

  3. A windowing and mapping strategy for gear tooth fault detection of a planetary gearbox

    Science.gov (United States)

    Liang, Xihui; Zuo, Ming J.; Liu, Libin

    2016-12-01

    When there is a single cracked tooth in a planet gear, the cracked tooth is enmeshed for very short time duration in comparison to the total time of a full revolution of the planet gear. The fault symptom generated by the single cracked tooth may be very weak. This study aims to develop a windowing and mapping strategy to interpret the vibration signal of a planetary gear at the tooth level. The fault symptoms generated by a single cracked tooth of the planet gear of interest can be extracted. The health condition of the planet gear can be assessed by comparing the differences among the signals of all teeth of the planet gear. The proposed windowing and mapping strategy is tested with both simulated vibration signals and experimental vibration signals. The tooth signals can be successfully decomposed and a single tooth fault on a planet gear can be effectively detected.

  4. 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.

  5. Tooth fragment reattachment technique on a pluri traumatized tooth

    OpenAIRE

    Giuseppe Lo Giudice; Frank Lipari; Angelo Lizio; Gabriel Cervino; Marco Cicciù

    2012-01-01

    This case report describes and analyses a tooth fragment reattachment technique used to resolve crown fractures of the anterior teeth. This treatment allows a conservative approach to traumatic coronal lesions offering a better possibility of maintaining aesthetics and function. The authors have illustrated here a clinical case of a fractured incisor. This case is characterized by several traumas on the same tooth that required different therapeutic solutions. We used an easy and ultra-conser...

  6. Tooth wear: when to treat, why, and how. Part two.

    Science.gov (United States)

    Larson, Thomas D

    2009-01-01

    Tooth wear has been described in the literature as physiologic--that is, normal, expected over the life span of an individual, and not creating a pathologic condition. It has also been described in pathologic terms as caused by stress, corrosion, and friction, utilizing a variety of mechanisms and affected by a host of endogenous and exogenous factors. From a clinician's point of view, when should we decide to restore a tooth or change the conditions in the mouth to protect the teeth; and what should we consider using to either prevent or restore abnormal--i.e, pathologic--tooth wear? This review in Part One (Northwest Dentistry, September-October 2009) looked at what is normal, non-pathologic tooth wear and etiologies associated with all forms of tooth wear. Part Two will discuss the effects of tooth wear in enamel and dentin, when it may be advisable to intervene in the wear processes diagnosed on specific patients, and what methods of prevention and restoration can be utilized to restore or maintain the dentition. This review will not look at the need for full mouth reconstruction due to wear.

  7. Is there a link between ovarian cancer and tooth agenesis?

    Science.gov (United States)

    Bonds, John; Pollan-White, Sarah; Xiang, Lilin; Mues, Gabriele; D’Souza, Rena

    2014-01-01

    An epidemiologic study from the year 2008 found a highly significant increase of congenital tooth agenesis in women with ovarian cancer suggesting that a common genetic etiology may predispose women to both conditions. The finding was reminiscent of a previously described family harboring an AXIN2 mutation which could be shown to segregate with both the tooth agenesis and the predisposition to colon cancer transmitted in this family. Since tooth agenesis as a marker for susceptibility to ovarian cancer would be of great relevance to both oncologists and women with inborn missing teeth, the relationship between the two disorders requires a thorough assessment. We examined DNA samples from the ovarian cancer patients who participated in the original study, to look for a possible genetic connection between their ovarian malignancies and tooth agenesis. MSX1, PAX9, AXIN2, EDA, WNT10A, BARX and BRCA1 genes were selected for sequence analysis as they may cause tooth agenesis, are expressed in the female reproductive system, and/or are involved in tumorigenesis in general or specifically in the ovary. Our study revealed evidence that one half of the dually affected patients had an independent causation of the two conditions, thus reducing the previously estimated ovarian cancer risk for women with congenital tooth agenesis quite significantly. PMID:24631698

  8. Diagnosing, managing, and preventing cracked tooth syndrome.

    Science.gov (United States)

    Wright, Edward F; Bartoloni, Joseph A

    2012-01-01

    Cracked tooth syndrome (CTS) can be a perplexing disorder to diagnose and manage. Many practitioners wonder whether the latest dental materials and adhesives can or should be used when restoring these teeth. The authors reviewed the literature and developed recommendations for how to diagnose and manage CTS and prevent it in susceptible teeth. As the population continues to age and people retain their teeth longer, it is anticipated that patients will present even more frequently with symptoms of CTS.

  9. 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

  10. Does Timing of Eruption in First Primary Tooth Correlate with that of First Permanent Tooth? A 9-years Cohort Study

    Science.gov (United States)

    Poureslami, Hamidreza; Asl Aminabadi, Naser; Sighari Deljavan, Alireza; Erfanparast, Leila; Sohrabi, Azin; Jamali, Zahra; Ghertasi Oskouei, Sina; Hazem, Kameliya; Shirazi, Sajjad

    2015-01-01

    Background and aims. Predicting the teeth eruption time is a valuable tool in pediatric dentistry since it can affects scheduling dental and orthodontic treatments. This study investigated the relationship between the eruption time of first primary and permanent teeth and the variation in the eruption time considering socioeconomic status (SES) in a 9-year population- based cohort study. Materials and methods. 307 subjects were examined at bimonthly intervals during the first and second years of life and then at six-month intervals until the eruption of first permanent tooth. Eruption times of primary and permanent tooth were recorded for each child. A modified form of Kuppuswamy’s scale was used to assess the SES. Results. Among 267 subjects completed all follow-ups, the eruption time for first primary and permanent teeth indicated a direct strong correlation; in that one month delayed or early eruption of firstprimary tooth resulted in 4.21 months delayed or early eruption of first appearing permanent tooth (r = 0.91, n = 267, P permanent teeth and SES (P = 0.67, P = 0.75, respectively). Conclusion. The eruption timing for the first primary tooth had a correlation with the first permanent tooth eruption tim-ing, while SES did not have any influence on eruption times. PMID:26236432

  11. Does Timing of Eruption in First Primary Tooth Correlate with that of First Permanent Tooth? A 9-year Cohort Study

    Directory of Open Access Journals (Sweden)

    Hamidreza Poureslami

    2015-06-01

    Full Text Available Background and aims. Predicting the teeth eruption time is a valuable tool in pediatric dentistry since it can affects scheduling dental and orthodontic treatments. This study investigated the relationship between the eruption time of first primary and permanent teeth and the variation in the eruption time considering socioeconomic status (SES in a 9-year population- based cohort study. Materials and methods. 307 subjects were examined at bimonthly intervals during the first and second years of life and then at six-month intervals until the eruption of first permanent tooth. Eruption times of primary and permanent tooth were recorded for each child. A modified form of Kuppuswamy’s scale was used to assess the SES. Results. Among 267 subjects completed all follow-ups, the eruption time for first primary and permanent teeth indicated a direct strong correlation; in that one month delayed or early eruption of first primary tooth resulted in 4.21 months delayed or early eruption of first appearing permanent tooth (r = 0.91, n = 267, P <0.001. No significant correlation was observed between the eruption time of first primary and first permanent teeth and SES (P = 0.67, P = 0.75, respectively. Conclusion. The eruption timing for the first primary tooth had a correlation with the first permanent tooth eruption tim-ing, while SES did not have any influence on eruption times.

  12. Does Timing of Eruption in First Primary Tooth Correlate with that of First Permanent Tooth? A 9-years Cohort Study.

    Science.gov (United States)

    Poureslami, Hamidreza; Asl Aminabadi, Naser; Sighari Deljavan, Alireza; Erfanparast, Leila; Sohrabi, Azin; Jamali, Zahra; Ghertasi Oskouei, Sina; Hazem, Kameliya; Shirazi, Sajjad

    2015-01-01

    Background and aims. Predicting the teeth eruption time is a valuable tool in pediatric dentistry since it can affects scheduling dental and orthodontic treatments. This study investigated the relationship between the eruption time of first primary and permanent teeth and the variation in the eruption time considering socioeconomic status (SES) in a 9-year population- based cohort study. Materials and methods . 307 subjects were examined at bimonthly intervals during the first and second years of life and then at six-month intervals until the eruption of first permanent tooth. Eruption times of primary and permanent tooth were recorded for each child. A modified form of Kuppuswamy's scale was used to assess the SES. Results. Among 267 subjects completed all follow-ups, the eruption time for first primary and permanent teeth indicated a direct strong correlation; in that one month delayed or early eruption of firstprimary tooth resulted in 4.21 months delayed or early eruption of first appearing permanent tooth (r = 0.91, n = 267, P eruption time of first primary and first permanent teeth and SES (P = 0.67, P = 0.75, respectively). Conclusion. The eruption timing for the first primary tooth had a correlation with the first permanent tooth eruption tim-ing, while SES did not have any influence on eruption times.

  13. SEM Analysis of Tooth Enamel

    OpenAIRE

    Azinović, Zoran; Keros, Jadranka; Buković, Dino; Azinović, Ana

    2003-01-01

    SEM analysis contains researches of tooth enamel surfaces of two populations. First group of samples is tooth enamel of prehistorically ancestor from Vu~edol and the second group of samples is enamel of modern Croatian citizen. Even on small number of human teeth samples from cooperage site of Vu~edol (3,000 BC) and today’s Croatian people, we can conclude about chewing biometry of prehistorically ancestors and today’s modern Croatian people, comparing interspecifically the mor...

  14. Orthodontic tooth movement and bioelectricity.

    OpenAIRE

    Karanth H; Shetty K

    2001-01-01

    Research in the field of orthodontics is now focused on the biology of tooth movement. Advanced molecular biology techniques has showed the researchers new avenue towards finding answers to the questions asked for the last few decades. Now it is possible for the researches to explore the lacunae in the field. One such field is, pharmaco-therapeutically or electrophysiologically enhancing the rate of tooth movement, improving the stability of the results, augmenting the anchorage. The voltage ...

  15. Electron paramagnetic resonance biophysical radiation dosimetry with tooth enamel

    Science.gov (United States)

    Khan, Rao F. H.

    This thesis deals with 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 radiation 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 the 100 mGy range can be easily reconstructed in teeth which 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 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

  16. Affective commitment to the employer brand: Development and validation of a scale

    OpenAIRE

    Fernandez-Lores, Susana; Gavilan, Diana; Avello, Maria; Blasco, Francisca

    2016-01-01

    In recent years employer branding has become increasingly important as a source of sustainable competitive advantage. Companies are trying to engender affective commitment in the best employees in a global labor market. We develop and validate a multidimensional scale to measure the strength of an employee´s affective commitment to the employer brand in five separate studies. In Study 1 and 2 the Affective Commitment to the Employer Brand (ACEB) scale was developed and tested for its factor s...

  17. 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

  18. 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

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

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    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.

  20. Drugs influencing orthodontic tooth movement: An overall review

    Directory of Open Access Journals (Sweden)

    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.

  1. Individual Differences in Self-Efficacy Development: The Effects of Goal Orientation and Affectivity

    Science.gov (United States)

    Gerhardt, Megan W.; Brown, Kenneth G.

    2006-01-01

    This study examined the moderating role of the individual differences of goal orientation and affectivity on self-efficacy development. Consistent with hypotheses, results indicate that both positive and negative affectivity moderate the impact of an enactive mastery training program on efficacy development, with those higher in positive…

  2. 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)

  3. Decoronation for the management of an ankylosed young permanent tooth.

    Science.gov (United States)

    Sapir, Shabtai; Shapira, Joseph

    2008-02-01

    Replacement resorption rate is a variable process, and is dependent on age, basal metabolic rate, extra-alveolar time, treatment prior to replantation, amount of root dentin, severity of trauma, and extent of periodontal ligament necrosis. In patients 7-16 years old a tooth is lost 3-7 years after the onset of root resorption. The complications that may develop as a consequence of ankylosis of a permanent incisor in children are due to the inevitable early loss of the traumatized tooth and local arrest of alveolar bone development. An ankylosed tooth should be removed before the changes become so pronounced that they compromise future prosthetic treatment. The treatment options may involve: interceptive regenerative treatment, early extraction of the ankylosed tooth, orthodontic space closure, intentional replantation, extraction of the ankylosed tooth followed with immediate ridge augmentation/preservation, auto-transplantation, single tooth dento-osseous osteotomy, and decoronation. The purpose of this article was to review the considerations involved in the decision-making concerning the use of the decoronation technique for the treatment of a permanent incisor diagnosed as ankylosed.

  4. Malignant melanoma and Charcot-Marie-Tooth disease: A further case

    Energy Technology Data Exchange (ETDEWEB)

    Manoukian, S.; Briscioli, V.; Lalatta, F. [Instituti Clinici di Perfezionamento, Milan (Italy)

    1997-01-20

    In a previous issue of this journal, Greene et al. described 2 patients with Charcot-Marie-Tooth (CMT) disease who later developed cutaneous malignant melanoma. Although the development of the two diseases in the same patient may have occurred by chance, the authors raised the possibility of a shared neural crest defect or a genetic linkage. Among the patients reported by Greene et al., one had a dominant form of CMT. The patient`s mother and brother were similarly affected. A paternal aunt died of melanoma. The second patient had a neuronal type of CMT. His brother showed the same disease, but the parents were not examined. 7 refs.

  5. Development of affective theory of mind across adolescence: disentangling the role of executive functions.

    Science.gov (United States)

    Vetter, Nora C; Altgassen, Mareike; Phillips, Louise; Mahy, Caitlin E V; Kliegel, Matthias

    2013-01-01

    Theory of mind, the ability to understand mental states, involves inferences about others' cognitive (cognitive theory of mind) and emotional (affective theory of mind) mental states. The current study explored the role of executive functions in developing affective theory of mind across adolescence. Affective theory of mind and three subcomponents of executive functions (inhibition, updating, and shifting) were measured. Affective theory of mind was positively related to age, and all three executive functions. Specifically, inhibition explained the largest amount of variance in age-related differences in affective theory of mind.

  6. HDAC6 is a therapeutic target in mutant GARS-induced Charcot-Marie-Tooth disease.

    Science.gov (United States)

    Benoy, Veronick; Van Helleputte, Lawrence; Prior, Robert; d'Ydewalle, Constantin; Haeck, Wanda; Geens, Natasja; Scheveneels, Wendy; Schevenels, Begga; Cader, M Zameel; Talbot, Kevin; Kozikowski, Alan P; Vanden Berghe, Pieter; Van Damme, Philip; Robberecht, Wim; Van Den Bosch, Ludo

    2018-02-05

    Peripheral nerve axons require a well-organized axonal microtubule network for efficient transport to ensure the constant crosstalk between soma and synapse. Mutations in more than 80 different genes cause Charcot-Marie-Tooth disease, which is the most common inherited disorder affecting peripheral nerves. This genetic heterogeneity has hampered the development of therapeutics for Charcot-Marie-Tooth disease. The aim of this study was to explore whether histone deacetylase 6 (HDAC6) can serve as a therapeutic target focusing on the mutant glycyl-tRNA synthetase (GlyRS/GARS)-induced peripheral neuropathy. Peripheral nerves and dorsal root ganglia from the C201R mutant Gars mouse model showed reduced acetylated α-tubulin levels. In primary dorsal root ganglion neurons, mutant GlyRS affected neurite length and disrupted normal mitochondrial transport. We demonstrated that GlyRS co-immunoprecipitated with HDAC6 and that this interaction was blocked by tubastatin A, a selective inhibitor of the deacetylating function of HDAC6. Moreover, HDAC6 inhibition restored mitochondrial axonal transport in mutant GlyRS-expressing neurons. Systemic delivery of a specific HDAC6 inhibitor increased α-tubulin acetylation in peripheral nerves and partially restored nerve conduction and motor behaviour in mutant Gars mice. Our study demonstrates that α-tubulin deacetylation and disrupted axonal transport may represent a common pathogenic mechanism underlying Charcot-Marie-Tooth disease and it broadens the therapeutic potential of selective HDAC6 inhibition to other genetic forms of axonal Charcot-Marie-Tooth disease. © The Author(s) (2018). Published by Oxford University Press on behalf of the Guarantors of Brain.

  7. Analysis of split tooth as an unstudied reason for tooth extraction

    OpenAIRE

    Osaghae, Ifueko Patience; Azodo, Clement Chinedu

    2014-01-01

    Background Split tooth is an unstudied reason for tooth extraction. The purpose of this study was to determine and analyze split tooth as a reason for extraction in a dental clinic in Benin City. Methods The prospective study was carried out on 669 patients having tooth extraction between May, 2005 and December, 2012. Over the period of the study, diagnosis and tooth extraction were done by three dentists of more five years practice experience. The indications for tooth extraction were noted ...

  8. Efficacy of gallium in tooth loss prevention

    Directory of Open Access Journals (Sweden)

    Aleksić Milena D.

    2016-01-01

    Full Text Available Introduction: Over the past three decades, gallium compounds have gained importance in medicine. Radioactive gallium and stable gallium nitrate are used as diagnostic and therapeutic agents in cancer and disorders of calcium and bone metabolism. In addition, gallium compounds have displayed anti inflammatory and immunosuppressive activity in animal models of human diseases. More recent studies have shown that gallium compounds may also function as antimicrobial agents. In the review, the potential application of gallium in the future treatment of periodontitis and prevention of tooth loss will be discussed. Gingival inflammation, bacterial infection, alveolar bone destruction and subsequent tooth loss are characteristic features of periodontal disease. Surgical techniques, mechanical debridement of the denuded root surface, and local or systemic application of antimicrobial agents are currently used treatments for periodontitis. However, the development of antibiotic resistance in bacteria has prompted a great need for new and alternative treatment methods for infection. Conclusion: The potential anti-periodontitis benefits of gallium are related to eradicating infection due to bacterial biofilms, increasing bone deposition and downregulating unwanted immune responses. Adjunctive use of gallium laser therapy with mechanical instrumentation in combination with gallium-containing gingival gels, toothpastes and mouth rinses may represent the final solutions for tooth loss prevention.

  9. 3-D finite element simulation for ultrasonic propagation in tooth.

    Science.gov (United States)

    Sun, Xiaoqing; Witzel, Erich A; Bian, Hongxin; Kang, Shaoying

    2008-07-01

    Ultrasonic testing of the tooth has been suggested as an alternative method of identifying dental pathology. Due to the complex geometry and low transmission efficiency of ultrasonic signals in tooth structures, it is difficult to establish one-to-one correspondence between ultrasonic behaviour and specific tooth pathologies both in vitro and in vivo. In order to facilitate ultrasonic diagnosis in dental applications, finite element modeling (FEM) was used to simulate ultrasonic wave propagation in teeth with several dental conditions. 3-D finite element tooth models were developed. The geometry of the tooth models was defined by 3-D images generated by scanning real tooth samples using an X-ray computerized tomography machine. Poro-elastic material was used to simulate the mechanical behaviour of the dentine. Numerical simulations of ultrasonic wave propagation were performed on the 3-D FEM models altered to mimic various dental conditions. The software ABAQUS was used as the calculator in the simulation. Excellent replication of ultrasonic behaviours by the FEM simulation was demonstrated through comparison of the simulation results with those of the actual ultrasonic testing on tooth specimens. Pathologies, such as caries, were also simulated on the finite element models. The unique influence of each dental condition on the patterns of ultrasonic waves propagating through the tooth (A-scan) was observed. Through FEM simulation, the influence of a particular dental pathology on ultrasonic wave pattern can be studied without the impact of other parameters. This will lead to a better understanding of how ultrasound could be applied to the diagnosis of pathology within teeth.

  10. Ultrasound crack detection in a simulated human tooth.

    Science.gov (United States)

    Culjat, M O; Singh, R S; Brown, E R; Neurgaonkar, R R; Yoon, D C; White, S N

    2005-03-01

    Currently, diagnosis of cracked teeth generally depends upon the overall clinical assessment, or on exclusion of other clinical possibilities, not primarily on the direct identification of cracks themselves. Owing to its short wavelength in hard tissues and associated high resolution, ultrasound has the potential to allow detection of cracks within tooth structure. However, ultrasound detection of dental cracks has not previously been achieved. The purpose was to determine if an ultrasound imaging system was capable of imaging cracks in simulated tooth structure. A complete ultrasound system including a novel transducer made of PLZT-98, a novel gallium-indium alloy coupling agent, and customized electronic and digital signal processing (DSP) algorithms was developed for the specific application of optimizing crack detection within teeth. A simulated tooth with a known and uniform internal structure and acoustic properties similar to those of natural enamel and dentin was designed to model a human tooth with a crack located in dentin deep to the dentino-enamel junction (DEJ). The distance between the DEJ and a crack of the simulated tooth were calculated. The system unequivocally distinguished between areas with and without a simulated crack. A unique ultrasound dental crack detection system using a novel transducer; a novel coupling agent; and customized electronic and digital signal processing (DSP) algorithms has been validated in a simulated tooth.

  11. Triple dens invaginatus in a single tooth: Rarest of rare case report

    Directory of Open Access Journals (Sweden)

    Amandeep Chhina

    2017-01-01

    Full Text Available Dens invaginatus is a rare malformation affecting the teeth. The teeth that are most commonly affected are the permanent maxillary lateral incisors. The mandibular posterior teeth are rarely affected by dens invaginatus. In most of the cases, a single dens invaginatus is seen affecting the tooth. Cases of double dens invaginatus affecting a single tooth are rare, and those of triple dens invaginatus in a single tooth are even rarer. Here, we present a case of a 14-year-old where three dens invaginatus were seen in the mandibular second premolar. This is the fourth case of three dens invaginatus in a single tooth as only three have been reported previously.

  12. Tracking official development assistance for reproductive health in conflict-affected countries: 2002-2011.

    Science.gov (United States)

    Patel, P; Dahab, M; Tanabe, M; Murphy, A; Ettema, L; Guy, S; Roberts, B

    2016-09-01

    To provide information on trends on official development assistance (ODA) disbursement patterns for reproductive health activities in 18 conflict-affected countries. Secondary data analysis. 18 conflict-affected countries and 36 non-conflict-affected countries. The Creditor Reporting System (CRS) database was analyzed for ODA disbursement for direct and indirect reproductive health activities to 18 conflict-affected countries (2002-2011). A comparative analysis was also made with 36 non-conflict-affected counties in the same 'least-developed' income category. Multivariate regression analyses examined associations between conflict status and reproductive health ODA and between reproductive needs and ODA disbursements. Patterns of ODA disbursements (constant U.S. dollars) for reproductive health activities. The average annual ODA disbursed for reproductive health to 18 conflict-affected countries from 2002 to 2011 was US$ 1.93 per person per year. There was an increase of 298% in ODA for reproductive health activities to the conflict-affected countries between 2002 and 2011; 56% of this increase was due to increases in HIV/AIDS funding. The average annual per capita reproductive health ODA disbursed to least-developed non-conflict-affected countries was 57% higher than to least-developed conflict-affected countries. Regression analyses confirmed disparities in ODA to and between conflict-affected countries. Despite increases in ODA for reproductive health for conflict-affected countries (albeit largely for HIV/AIDS activities), considerable disparities remains. Study tracking 10 years of aid for reproductive aid shows major disparities for conflict-affected countries. © 2016 The Authors. BJOG An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of Royal College of Obstetricians and Gynaecologists.

  13. 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.

  14. Treatment of an avulsed maxillary permanent central incisor by autotransplantation of a primary canine tooth.

    Science.gov (United States)

    Sönmez, D; Dalci, K; Tunç, E Sen

    2008-07-01

    To present a case in which an avulsed permanent maxillary central incisor was replaced by autotransplantation of a primary canine tooth. The present case describes transplantation of a primary canine tooth into the space left by an avulsed permanent maxillary central incisor after a delay of several days. After root canal treatment, the primary canine tooth was extracted and placed into the prepared socket. To provide better adaptation of the donor tooth, the recipient alveolar site was remodeled using surgical burs. Semi-rigid splinting was maintained for 15 days. The crown of the primary canine was reshaped with composite resin and with an interim prosthesis, preventing movement of the lateral incisor tooth into the space of the transplanted canine. After 24-month follow-up the autotransplanted primary canine showed ankylosis but the tooth was in an acceptable state. The use of permanent tooth autotransplantation has been well documented. However a literature search revealed only one case report on the autotransplantation of primary teeth. Long term results of primary tooth autotransplantation are scarce but the procedure in this case report could be considered as a temporary space maintainer for the treatment of a patient with a lost permanent incisor under 10 years of age. Success of primary tooth autotransplantation may be affected by several factors, such as case selection, extra oral time, surgical and endodontic procedures.

  15. Detecting gear tooth fracture in a high contact ratio face gear mesh

    Science.gov (United States)

    Zakrajsek, James J.; Handschuh, Robert F.; Lewicki, David G.; Decker, Harry J.

    1995-01-01

    This paper summarized the results of a study in which three different vibration diagnostic methods were used to detect gear tooth fracture in a high contact ratio face gear mesh. The NASA spiral bevel gear fatigue test rig was used to produce unseeded fault, natural failures of four face gear specimens. During the fatigue tests, which were run to determine load capacity and primary failure mechanisms for face gears, vibration signals were monitored and recorded for gear diagnostic purposes. Gear tooth bending fatigue and surface pitting were the primary failure modes found in the tests. The damage ranged from partial tooth fracture on a single tooth in one test to heavy wear, severe pitting, and complete tooth fracture of several teeth on another test. Three gear fault detection techniques, FM4, NA4*, and NB4, were applied to the experimental data. These methods use the signal average in both the time and frequency domain. Method NA4* was able to conclusively detect the gear tooth fractures in three out of the four fatigue tests, along with gear tooth surface pitting and heavy wear. For multiple tooth fractures, all of the methods gave a clear indication of the damage. It was also found that due to the high contact ratio of the face gear mesh, single tooth fractures did not significantly affect the vibration signal, making this type of failure difficult to detect.

  16. Development of Affective Theory of Mind Across Adolescence: Disentangling the Role of Executive Functions

    NARCIS (Netherlands)

    Vetter, N.C.; Altgassen, A.M.; Phillips, L.H.; Mahy, C.E.V.; Kliegel, M.

    2013-01-01

    Theory of mind, the ability to understand mental states, involves inferences about others' cognitive (cognitive theory of mind) and emotional (affective theory of mind) mental states. The current study explored the role of executive functions in developing affective theory of mind across

  17. The Development and Application of Affective Assessment in an Upper-Level Cell Biology Course

    Science.gov (United States)

    Kitchen, Elizabeth; Reeve, Suzanne; Bell, John D.; Sudweeks, Richard R.; Bradshaw, William S.

    2007-01-01

    This study exemplifies how faculty members can develop instruments to assess affective responses of students to the specific features of the courses they teach. Means for assessing three types of affective responses are demonstrated: (a) student attitudes towards courses with differing instructional objectives and methodologies, (b) student…

  18. High-throughput identification of small molecules that affect human embryonic vascular development

    NARCIS (Netherlands)

    Vazão, Helena; Rosa, Susana; Barata, Tânia; Costa, Ricardo; Pitrez, Patrícia R.; Honório, Inês; De Vries, Margreet R.; Papatsenko, Dimitri; Benedito, Rui; Saris, Daniel; Khademhosseini, Ali; Quax, Paul H.A.; Pereira, Carlos F.; Mercader, Nadia; Fernandes, Hugo; Ferreira, Lino

    2017-01-01

    Birth defects, which are in part caused by exposure to environmental chemicals and pharmaceutical drugs, affect 1 in every 33 babies born in the United States each year. The current standard to screen drugs that affect embryonic development is based on prenatal animal testing; however, this approach

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

    OpenAIRE

    Rahayu, Yani Corvianindya; Setyorini, dyah

    2009-01-01

    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 ag...

  20. Esthetic management of a primary double tooth using a silicone putty guide: a case report.

    Science.gov (United States)

    Agarwal, Ravi; Chaudhry, Kalpna; Yeluri, Ramakrishna; Munshi, Autar Krishen

    2013-03-01

    The term double tooth is often used to describe fusion and gemination. The development of isolated large or joined teeth is not rare, but the literature is confusing when the appropriate terminology is presented. The objective of this paper is to present a case of a primary double tooth in a 5-year-old girl with a history of trauma. The tooth was endodontically treated and esthetic management was carried out using a silicone putty guide.

  1. Tooth polishing: The current status

    Directory of Open Access Journals (Sweden)

    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.

  2. Coping with cracked tooth syndrome.

    Science.gov (United States)

    Benenati, F W

    1996-01-01

    Cracked tooth syndrome typically poses a diagnostic challenge for the dentist. Symptoms include tenderness to biting on certain foods, often poorly localized, and occasional thermal sensitivity. Knowing where to look for this entity, especially in the mandibular molar region, can be especially helpful. Treatment of the tooth depends on the degree of pulpal involvement and the extent of the crack. Cuspal coverage is required of all cracked posterior teeth that are retainable. Root canal therapy is included if symptoms persist or if pulpal pathosis exists at the outset. Cracks extending beyond the osseous crest indicate a poor prognosis. Armed with this knowledge, the dentist can overcome many cracked tooth dilemmas, resulting in satisfaction for both patient and practitioner alike.

  3. Negative affect is associated with development and persistence of chemical intolerance

    DEFF Research Database (Denmark)

    Skovbjerg, Sine; Christensen, Karl Bang; Ebstrup, Jeanette Frost

    2015-01-01

    OBJECTIVE: Chemical intolerance (CI) is characterised by negative health effects attributed to a heightened responsiveness to common airborne chemicals. This longitudinal study explored the hypothesised role of negative affect in the development and persistence of CI in a general population...

  4. Development of upper respiratory tract microbiota in infancy is affected by mode of delivery

    NARCIS (Netherlands)

    Bosch, A.A.T.M.; Levin, E.; van Houten, M.A.; Hasrat, R.; Kalkman, G.; Biesbroek, G.; de Steenhuijsen Piters, W.A.A.; de Groot, P.-K.C.M.; Pernet, P.; Keijser, B.J.F.; Sanders, E.A.M.; Bogaert, D.

    2016-01-01

    Birth by Caesarian section is associated with short- and long-term respiratory morbidity. We hypothesized that mode of delivery affects the development of the respiratory microbiota, thereby altering its capacity to provide colonization resistance and consecutive pathobiont overgrowth and

  5. Diagnosis, therapy, and prevention of the cracked tooth syndrome.

    Science.gov (United States)

    Geurtsen, Werner; Schwarze, Thomas; Günay, Huesamettin

    2003-06-01

    Many morphologic, physical, and iatrogenic factors, such as deep grooves, pronounced intraoral temperature fluctuation, poor cavity preparation design, and wrong selection of restorative materials, may predispose posterior teeth to an incomplete fracture. The resulting cracked tooth syndrome is frequently associated with bizarre symptoms that may complicate diagnosis and can persist for many years. Epidemiologic data reveal that splits or fractures are the third most common cause of tooth loss in industrialized countries, primarily affecting maxillary molars and premolars and mandibular molars. This finding indicates that the cracked tooth syndrome is of high clinical importance. Thus, at-risk teeth should be reinforced early, for instance by castings with cusp coverage or by internal splinting with adhesive ceramic restorations.

  6. Primary culprit for tooth loss!!

    Science.gov (United States)

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

    2016-01-01

    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. to examine whether the major reason for tooth extraction is dental caries or periodontal disease. 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. 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. 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.

  7. Gearbox Tooth Cut Fault Diagnostics Using Acoustic Emission and Vibration Sensors — A Comparative Study

    Directory of Open Access Journals (Sweden)

    Yongzhi Qu

    2014-01-01

    Full Text Available In recent years, acoustic emission (AE sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibration analysis-based techniques using the same sampling rate. To answer the question, this paper presents a comparative study for gearbox tooth damage level diagnostics using AE and vibration measurements, the first known attempt to compare the gearbox fault diagnostic performance of AE- and vibration analysis-based approaches using the same sampling rate. Partial tooth cut faults are seeded in a gearbox test rig and experimentally tested in a laboratory. Results have shown that the AE-based approach has the potential to differentiate gear tooth damage levels in comparison with the vibration-based approach. While vibration signals are easily affected by mechanical resonance, the AE signals show more stable performance.

  8. On gear tooth stiffness evaluation

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard; Jørgensen, Martin Felix

    2014-01-01

    The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation...... and secondly the size of the contact. In the FE calculation the true gear tooth root profile is applied. The meshing stiffnesses of gears are highly non-linear, it is however found that the stiffness of an individual tooth can be expressed in a linear form assuming that the contact width is constant. © 2014...... Elsevier Ltd. All rights reserved....

  9. Tooth fracture risk analysis based on a new finite element dental structure models using micro-CT data.

    Science.gov (United States)

    Chen, G; Fan, W; Mishra, S; El-Atem, A; Schuetz, M A; Xiao, Y

    2012-10-01

    The finite element (FE) analysis is an effective method to study the strength and predict the fracture risk of endodontically-treated teeth. This paper presents a rapid method developed to generate a comprehensive tooth FE model using data retrieved from micro-computed tomography (μCT). With this method, the inhomogeneity of material properties of teeth was included into the model without dividing the tooth model into different regions. The material properties of the tooth were assumed to be related to the mineral density. The fracture risk at different tooth portions was assessed for root canal treatments. The micro-CT images of a tooth were processed by a Matlab software programme and the CT numbers were retrieved. The tooth contours were obtained with thresholding segmentation using Amira. The inner and outer surfaces of the tooth were imported into Solidworks and a three-dimensional (3D) tooth model was constructed. An assembly of the tooth model with the periodontal ligament (PDL) layer and surrounding bone was imported into ABAQUS. The material properties of the tooth were calculated from the retrieved CT numbers via ABAQUS user's subroutines. Three root canal geometries (original and two enlargements) were investigated. The proposed method in this study can generate detailed 3D finite element models of a tooth with different root canal enlargements and filling materials, and would be very useful for the assessment of the fracture risk at different tooth portions after root canal treatments. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  10. Maternal regulation of child affect in externalizing and typically-developing children.

    Science.gov (United States)

    Lougheed, Jessica P; Hollenstein, Tom; Lichtwarck-Aschoff, Anna; Granic, Isabela

    2015-02-01

    Temporal contingencies between children's affect and maternal behavior play a role in the development of children's externalizing problems. The goal of the current study was to use a microsocial approach to compare dyads with externalizing dysregulation (N =191) to healthy controls (N = 54) on maternal supportive regulation of children's negative and positive affect. Children were between the ages of 8 and 12 years. Mother-child dyads participated in conflict and positive discussions, and child affect and maternal supportive affect regulation were coded in real time. First, no group differences on overall levels of mother supportive regulation or child affect were found. Second, three event history analyses in a 2-level Cox hazard regression framework were used to predict the hazard rate of (a) maternal supportiveness, and of children's transitions (b) out of negative affect and (c) into positive affect. The hazard rate of maternal supportiveness, regardless of child affect, was not different between groups. However, as expected, the likelihood of mothers' supportive responses to children's negative affect was lower in externalizing than comparison dyads. In addition, children with externalizing problems were significantly less likely than typically developing children to transition out of negative affect in response to maternal supportiveness. The likelihood of both typically developing children and children with externalizing problems transitioning into positive affect were not related to specific occurrences of maternal supportiveness. Results of the current study show the importance of temporal dynamics in mother-child interactions in the emergence of children's externalizing problems. PsycINFO Database Record (c) 2015 APA, all rights reserved.

  11. Psychometrics evaluation of Charcot-Marie-Tooth Neuropathy Score (CMTNSv2) second version, using Rasch analysis.

    Science.gov (United States)

    Sadjadi, Reza; Reilly, Mary M; Shy, Michael E; Pareyson, Davide; Laura, Matilde; Murphy, Sinead; Feely, Shawna M E; Grider, Tiffany; Bacon, Chelsea; Piscosquito, Giuseppe; Calabrese, Daniela; Burns, Ted M

    2014-09-01

    Charcot-Marie-Tooth Neuropathy Score second version (CMTNSv2) is a validated clinical outcome measure developed for use in clinical trials to monitor disease impairment and progression in affected CMT patients. Currently, all items of CMTNSv2 have identical contribution to the total score. We used Rasch analysis to further explore psychometric properties of CMTNSv2, and in particular, category response functioning, and their weight on the overall disease progression. Weighted category responses represent a more accurate estimate of actual values measuring disease severity and therefore could potentially be used in improving the current version. © 2014 Peripheral Nerve Society.

  12. Effects of tooth extraction on smile esthetics and the buccal corridor: A meta-analysis

    Directory of Open Access Journals (Sweden)

    Hsin-Chung Cheng

    2016-12-01

    Conclusion: Tooth extraction does not affect smile esthetics or buccal corridor. However, additional detailed, large-scale, double-blinded, and randomized controlled trials are required for further evaluation.

  13. Temperament and perception of tooth bleaching results

    Directory of Open Access Journals (Sweden)

    Katarzyna Mehr

    2016-09-01

    Full Text Available Background . The neurophysiological process of perceiving the results of tooth bleaching requires the correct interaction between the central nervous system and the organs of sight. Exaggerated beliefs concerning defective facial features may enhance inner attitudes about one’s own color of dentition, as well as a feeling of dissatisfaction with the degree of leaching. Objectives. The study aimed to assess the degree of the patient satisfaction with the results of tooth bleaching in relation to their temperament. Material and methods. There were 68 generally healthy volunteers, aged 28–38 years, with external discolorations of the teeth. They had never undergone dental bleaching and their frontal teeth did not have any fillings. After clinical evaluation and the completion of formalities, the patients were asked to fill in Strelau’s temperament questionnaire. Questionnaires and visual status were assessed three times by three doctors: before bleaching, and then 24 hours and two weeks after the home-bleaching operation, which was done with the use of Opalescence (Ultradent in uniform sequence. Results . There were practically no adverse side results, except a periodic dentin hypersensitivity that occurred periodically in 44 patients. The results of the visual assessment performed by the physicians did not differ. The questionnaire data showed that women were more critical of the results in relation to the expectations. Among elancholics, full satisfaction was declared by 41%, whereas among sanguine people, full satisfaction was obtained by 85%. Satisfaction with the aesthetic results was associated with bleaching by at least 4 degrees. Conclusions . Patients’ temperament affects their subjective evaluation of the effectiveness of tooth bleaching, which should be taken into consideration in the patient’s individual dental treatment plan.

  14. Forensic Identification Based on Tooth Material

    Directory of Open Access Journals (Sweden)

    Elza Ibrahim Auerkari

    2015-10-01

    Full Text Available Human teeth are the most robust and stable parts of the body, providing biological clue material for forensic purposes even when most of the oter means of identifcation have been seriously affected by adverse environmental conditions. In particular blood grouping, isozymes, serum proteins and DNA polymorhphisms can be detected from teeth that protect these identification markers in addition to the traditional dental records. While in general the value of traditional dental records in the forensic work is decreasing eg due to mproved dental care, the newer means of identification from tooth material provide considerable promise for effective identification in difficult cases.The DNA analysis from tooth material has been shown to ba a viable route in forensic analysis, when other material for such an analysis is unusable. However in most cases useful biologic material other than teeth is abailable, and then DNA analysis can be made from other tissue with less effort than by using teeth. Also, in cases with lacking other tissue, blood grouping, isozymes and serum proteins may provide cheaper inherited combinations of blood grouping, isozymes and serum proteins can be treated similary to polymorphic DNA loci as independent markers, their identification can be managed if the false positives and negatives in analysis can be minimmised, and the corresponding frequencies of occurrence are known.It was the purpose of the present work to review the methods of forensic identification from tooth material, based on analysis of blood grouping, isozymes and serum proteins. It appears that such a combined analysis provides a robust method for forensic purposes. Nevertheless, for efficient identification it is recommended that as many (multiple forensic methods as possible are combined, so that faster and cheaper methods such as imminent medical forensics are used first, and more thorough analysis is used to support and complement these methods.

  15. Epithelial topography for repetitive tooth formation

    Directory of Open Access Journals (Sweden)

    Marcia Gaete

    2015-12-01

    Full Text Available During the formation of repetitive ectodermally derived organs such as mammary glands, lateral line and teeth, the tissue primordium iteratively initiates new structures. In the case of successional molar development, new teeth appear sequentially in the posterior region of the jaw from Sox2+ cells in association with the posterior aspect of a pre-existing tooth. The sequence of molar development is well known, however, the epithelial topography involved in the formation of a new tooth is unclear. Here, we have examined the morphology of the molar dental epithelium and its development at different stages in the mouse in vivo and in molar explants. Using regional lineage tracing we show that within the posterior tail of the first molar the primordium for the second and third molar are organized in a row, with the tail remaining in connection with the surface, where a furrow is observed. The morphology and Sox2 expression of the tail retains characteristics reminiscent of the earlier stages of tooth development, such that position along the A-P axes of the tail correlates with different temporal stages. Sox9, a stem/progenitor cell marker in other organs, is expressed mainly in the suprabasal epithelium complementary with Sox2 expression. This Sox2 and Sox9 expressing molar tail contains actively proliferating cells with mitosis following an apico-basal direction. Snail2, a transcription factor implicated in cell migration, is expressed at high levels in the tip of the molar tail while E-cadherin and laminin are decreased. In conclusion, our studies propose a model in which the epithelium of the molar tail can grow by posterior movement of epithelial cells followed by infolding and stratification involving a population of Sox2+/Sox9+ cells.

  16. Life of a Tooth: A Visual Timeline

    Medline Plus

    Full Text Available ... more Children's Oral Health What is Baby Bottle Tooth Decay? What is Orofacial Pain? How Do I Care ... Is My Child at Risk for Early Childhood Tooth Decay? Learn what those dental words mean. The Life ...

  17. Life of a Tooth: A Visual Timeline

    Science.gov (United States)

    ... more Children's Oral Health What is Baby Bottle Tooth Decay? What is Orofacial Pain? How Do I Care ... Is My Child at Risk for Early Childhood Tooth Decay? Learn what those dental words mean. The Life ...

  18. 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 | ...

  19. Life of a Tooth: A Visual Timeline

    Medline Plus

    Full Text Available ... InfoBites Quick Reference Learn more Children's Oral Health What is Baby Bottle Tooth Decay? Why is Oral ... Tooth Decay? The History of Dental Advances Learn what those dental words mean. The Life of a ...

  20. The cracked tooth syndrome: an elusive diagnosis.

    Science.gov (United States)

    Türp, J C; Gobetti, J P

    1996-10-01

    The authors review the literature and present a case of cracked tooth syndrome. Special emphasis is placed on diagnostic problems associated with this syndrome. The case report demonstrates classic and atypical features of cracked tooth syndrome.

  1. Automatic detection of tooth cracks in optical coherence tomography images.

    Science.gov (United States)

    Kim, Jun-Min; Kang, Se-Ryong; Yi, Won-Jin

    2017-02-01

    The aims of the present study were to compare the image quality and visibility of tooth cracks between conventional methods and swept-source optical coherence tomography (SS-OCT) and to develop an automatic detection technique for tooth cracks by SS-OCT imaging. We evaluated SS-OCT with a near-infrared wavelength centered at 1,310 nm over a spectral bandwidth of 100 nm at a rate of 50 kHz as a new diagnostic tool for the detection of tooth cracks. The reliability of the SS-OCT images was verified by comparing the crack lines with those detected using conventional methods. After performing preprocessing of the obtained SS-OCT images to emphasize cracks, an algorithm was developed and verified to detect tooth cracks automatically. The detection capability of SS-OCT was superior or comparable to that of trans-illumination, which did not discriminate among the cracks according to depth. Other conventional methods for the detection of tooth cracks did not sense initial cracks with a width of less than 100 μm. However, SS-OCT detected cracks of all sizes, ranging from craze lines to split teeth, and the crack lines were automatically detected in images using the Hough transform. We were able to distinguish structural cracks, craze lines, and split lines in tooth cracks using SS-OCT images, and to automatically detect the position of various cracks in the OCT images. Therefore, the detection capability of SS-OCT images provides a useful diagnostic tool for cracked tooth syndrome.

  2. Affective commitment to the employer brand: Development and validation of a scale

    Directory of Open Access Journals (Sweden)

    Susana Fernandez-Lores

    2016-01-01

    Full Text Available In recent years employer branding has become increasingly important as a source of sustainable competitive advantage. Companies are trying to engender affective commitment in the best employees in a global labour market. In this study, we develop and validate a multidimensional scale to measure the strength of an employee's affective commitment to the employer brand in five separate studies. In Studies 1 and 2 the Affective Commitment to the Employer Brand (ACEB scale was developed and tested for its structure, reliability and convergent validity. Study 3 examines additional reliability and discriminant validity. Study 4 provides evidence of external validity. Study 5 examines the scale's nomological validity showing that a positive experience with the employer brand is important in making the employee develop affective commitment towards it. The limitations of the scale and the boundary conditions of its applicability are also discussed.

  3. TOOTH AGENESIS - THE PROBLEM AND ITS SOLVING IN OUR PRACTICE, PREVALENCE AND RELATION WITH OTHER DEFORMITIES.

    Directory of Open Access Journals (Sweden)

    Greta Yordanova

    2015-09-01

    Full Text Available Tooth agenesis is an orthodontic abnormality affecting the number of teeth. This leads to various types of malocclusion, disturbance in the masticatory function and poor esthetics. This survey includes 1510 orthodontic patients treated by us. Two hundred and seven (13.71% of all of the patients have been diagnosed with tooth agenesis. One hundred thirty-seven (8.87% of the treated patients have tooth agenesis, while 31 (2.05% of all of the patients and 23.13% of the patients with tooth agenesis have tooth agenesis also in the third molars. In general 207 of the patients have tooth agenesis of 637 teeth. In 104 patients there are 348 absent germs of third molars. Chiefly the tooth agenesis affects one or two teeth. Fifty three patients 39.55% are with one missing tooth and 50 of them – 37.31% are with two missing teeth. It affects most often lower second premolars, followed up by the upper lateral incisors, the next group is the group of the upper second premolars. In 5 of our patients we diagnosed and treated tooth agenesis of the canines, in two of those patients the tooth agenesis of the canines was bilateral. This is a very rare problem that creates to serious occlusal dysfunctions. We found out that the ratio of distribution among the genders is at higher level for the female patients (9.70% compared to the male patients (7.51%. Knowing the rate of the problem among a certain nation is very important for its early diagnosis and considering the optimal treatment plan.

  4. Genetic Basis of Nonsyndromic and Syndromic Tooth Agenesis

    Science.gov (United States)

    Ye, Xiaoqian; Attaie, Ali B.

    2016-01-01

    Human dentition development is a long and complex process which involves a series of reciprocal and sequential interactions between the embryonic stomodeal epithelium and the underlying neural crest–derived mesenchyme. Despite environment disturbances, tooth development is predominantly genetically controlled. To date, more than 200 genes have been identified in tooth development. These genes implied in various signaling pathways such as the bone morphogenetic protein, fibroblast growth factor, sonic hedgehog homolog, ectodysplasin A, wingless-type MMTV integration site family (Wnt), and transform growth factor pathways. Mutations in any of these strictly balanced signaling cascades may cause arrested odontogenesis and/or other dental defects. This article aims to review current knowledge about the genetic mechanisms responsible for selective nonsyndromic tooth agenesis in humans and to present a detailed summary of syndromes with hypodontia as regular features and their causative genes. PMID:27895972

  5. Intentional replantation of periodontally compromised hopeless tooth

    OpenAIRE

    Nagappa, G.; Aspalli, Shivanand; Devanoorkar, Archana; Shetty, Sudhir; Parab, Prachi

    2013-01-01

    Aesthetic considerations have influenced the management of dental maladies in varying degrees for many years. Even single tooth mal-alignment makes the patient to approach a dentist. Intentional replantation is a procedure in which an intentional tooth extraction is performed followed by reinsertion of the extracted tooth. Many authors agree that it should be reserved as the last resort to save a tooth after other procedures have failed or would likely to fail. The main reason of failure in r...

  6. Tooth agenesis association with self-reported family history of cancer.

    Science.gov (United States)

    Küchler, E C; Lips, A; Tannure, P N; Ho, B; Costa, M C; Granjeiro, J M; Vieira, A R

    2013-02-01

    It has been proposed that tooth agenesis and cancer development share common molecular pathways. We performed a cross-sectional study to investigate the epidemiological and molecular association between tooth agenesis and self-reported family history of cancer. Eighty-two individuals with tooth agenesis and 328 individuals with no birth defect were recruited from the same institution. Tooth agenesis was assessed in permanent teeth and was defined based on the age of the participants and when initial tooth formation should be radiographically visible. We also investigated the role of genes involved in dental development that have been implicated in tumorigenesis, and 14 markers in AXIN2, FGF3, FGF10, and FGFR2 were genotyped. Individuals with tooth agenesis had an increased risk of having a family history of cancer (p = 0.00006; OR = 2.7; 95% C.I., 1.6-4.4). There were associations between AXIN2, FGF3, FGF10, and FGFR2 with tooth agenesis [i.e., individuals who carried the polymorphic allele of FGFR2 (rs1219648) presented higher risk for having premolar agenesis (p = 0.02; OR = 1.8; 95% C.I., 1.1-3.0)]. In conclusion, tooth agenesis was associated with positive self-reported family history of cancer and with variants in AXIN2, FGF3, FGF10, and FGFR2. Prospective studies are needed to confirm if tooth agenesis can be used as a risk marker for cancer.

  7. Photoelastic stress analysis of implant-tooth connected prostheses with segmented and nonsegmented abutments.

    Science.gov (United States)

    Ochiai, Kent T; Ozawa, Shogo; Caputo, Angelo A; Nishimura, Russell D

    2003-05-01

    There is some question about whether implant abutment selection affects the transfer of load between connected implants and natural teeth. The purpose of this study was to compare stress transfer patterns with either 1 or 2 posterior implants connected to a single anteriorly located simulated natural tooth with either 1 or 2 segmented and nonsegmented implant abutments under relevant functional loads by use of the photoelastic stress analysis technique. A model of a human left mandible, edentulous posterior to the first premolar, with two 3.75-mm x 13-mm screw-type implants embedded within the edentulous area, was fabricated from photoelastic materials. The implants were in the first and second molar positions. Two fixed partial denture prosthetic restorations were fabricated with either segmented conical abutments or nonsegmented UCLA abutments. Vertical occlusal loads were applied at fixed locations on the restorations. The photoelastic stress fringes that developed in the supporting mandible were monitored visually and recorded photographically. The stress intensity (number of fringes), stress concentrations (closeness of fringes), and their locations were subjectively compared. Loading on the restoration over the simulated tooth generated apical stresses of similar intensity (fringe order) at the tooth and the first molar implant for both abutment types. Low-level stress was transferred to the second molar implant. Loading directed on the implant-supported region of the restoration demonstrated low transfer of stress to the simulated tooth. Nonvertical stress transfer with slightly higher intensity was observed for the nonsegmented abutment. Within the limitations of this simulation study, stress distribution and intensity for the 2 implant conditions was similar for segmented and nonsegmented abutment designs. Magnitude of stresses observed for both abutment designs was similar for the single implant condition. Vertical loading produced more nonaxial stresses

  8. 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.

  9. Charcot-Marie-Tooth Disease

    Science.gov (United States)

    Charcot-Marie-Tooth disease (CMT) is a group of genetic nerve disorders. It is named after the three doctors who first identified it. ... a nerve biopsy. There is no cure. The disease can be so mild you don't realize ...

  10. Diagnosis of cracked tooth syndrome

    Directory of Open Access Journals (Sweden)

    Sebeena Mathew

    2012-01-01

    Full Text Available The incidences of cracks in teeth seem to have increased during the past decade. Dental practitioners need to be aware of cracked tooth syndrome (CTS in order to be successful at diagnosing CTS. Early diagnosis has been linked with successful restorative management and predictably good prognosis. The purpose of this article is to highlight factors that contribute to detecting cracked teeth.

  11. Diagnosis of cracked tooth syndrome.

    Science.gov (United States)

    Mathew, Sebeena; Thangavel, Boopathi; Mathew, Chalakuzhiyil Abraham; Kailasam, Sivakumar; Kumaravadivel, Karthick; Das, Arjun

    2012-08-01

    The incidences of cracks in teeth seem to have increased during the past decade. Dental practitioners need to be aware of cracked tooth syndrome (CTS) in order to be successful at diagnosing CTS. Early diagnosis has been linked with successful restorative management and predictably good prognosis. The purpose of this article is to highlight factors that contribute to detecting cracked teeth.

  12. Diagnosis of cracked tooth syndrome

    OpenAIRE

    Mathew, Sebeena; Thangavel, Boopathi; Mathew, Chalakuzhiyil Abraham; Kailasam, SivaKumar; Kumaravadivel, Karthick; Das, Arjun

    2012-01-01

    The incidences of cracks in teeth seem to have increased during the past decade. Dental practitioners need to be aware of cracked tooth syndrome (CTS) in order to be successful at diagnosing CTS. Early diagnosis has been linked with successful restorative management and predictably good prognosis. The purpose of this article is to highlight factors that contribute to detecting cracked teeth.

  13. Equine Odontoclastic Tooth Resorption and Hypercementosis: Histopathologic Features.

    Science.gov (United States)

    Smedley, R C; Earley, E T; Galloway, S S; Baratt, R M; Rawlinson, J E

    2015-09-01

    Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a painful progressive condition of older horses that involves multiple teeth, including canines and incisors. EOTRH is uncommonly recognized by veterinary pathologists and in some cases may be misdiagnosed as cementoblastoma. The cause is unknown. The goals of this study were to describe the histopathologic features of EOTRH in 17 affected horses from the United States and to increase awareness of this condition. Samples ranged from affected tooth to the entire rostral mandible and maxilla. Affected teeth exhibited cemental hyperplasia and lysis. The marked proliferation of cementum in severe cases caused bulbous enlargement of the intra-alveolar portions of affected teeth. Several teeth contained necrotic debris, bacteria, and plant material in the regions of cemental lysis. All horses exhibited dentinal lysis in at least affected tooth, and several contained necrotic debris in these regions. Endodontic disease was often present with inflammation, lysis, necrotic debris, fibrosis, and/or a thin rim of atubular mineralized tissue in the pulp cavity. Periodontal disease was a common feature that was primarily characterized by moderate lymphoplasmacytic inflammation. Resorption with secondary hypercementosis appears to begin on the external surface of the teeth rather than within the pulp cavity. Distinguishing EOTRH from other diseases requires a complete history that includes the number and location of affected teeth, a gross description of regional hard/soft tissue health, and radiographic findings. © The Author(s) 2015.

  14. Leukotrienes in orthodontic tooth movement.

    Science.gov (United States)

    Mohammed, A H; Tatakis, D N; Dziak, R

    1989-03-01

    Prostaglandins (PGs) and leukotrienes (LTs) are products of arachidonic acid conversion. PGs have an established role in mediating orthodontic tooth movement. The role of LTs in modulating or mediating orthodontic tooth movement was investigated in this study. One hundred thirty-two Sprague-Dawley rats were used; the animals weighed 300 to 400 gm with equal numbers of male and female rats. They were divided into five main groups of 24 animals each and a sham group of 12 animals. An orthodontic appliance was placed and activated on all the animals except the sham group; in this group the appliances were not active. Each main group was given one of the following treatments daily: distilled water, 5% gum arabic solution, PG synthesis inhibitor indomethacin, LT synthesis inhibitor AA861, and a combination of both drugs. Each group was divided into six subgroups of four animals; the animals were killed at either 1, 3, 5, 7, 10, or 14 days, and tooth movement measured. The three sham subgroups received distilled water and were killed at 1, 7, or 10 days. The first maxillary molar (the moved tooth) and surrounding tissues were removed from all animals in the sham group and the subgroups killed at 1, 7, and 10 days in the gum arabic solution group and the LT synthesis inhibitor group. Prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) were extracted, measured with radioimmunoassay (RIA), and standardized per milligram of protein in the sample. A significant inhibition of tooth movement occurred beginning on day 7 in the indomethacin, AA861, and combination groups; there was no significant difference among these groups.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Embodied Brains, Social Minds, Cultural Meaning: Integrating Neuroscientific and Educational Research on Social-Affective Development

    Science.gov (United States)

    Immordino-Yang, Mary Helen; Gotlieb, Rebecca

    2017-01-01

    Social-affective neuroscience is revealing that human brain development is inherently social--our very nature is organized by nurture. To explore the implications for human development and education, we present a series of interdisciplinary studies documenting individual and cultural variability in the neurobiological correlates of emotional…

  16. 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

  17. Changes in gravitational force affect gene expression in developing organ systems at different developmental times

    OpenAIRE

    Shimada, Naoko; Sokunbi, Gbolabo; Moorman, Stephen J

    2005-01-01

    Abstract Background Little is known about the affect of microgravity on gene expression, particularly in vivo during embryonic development. Using transgenic zebrafish that express the gfp gene under the influence of a β-actin promoter, we examined the affect of simulated-microgravity on GFP expression in the heart, notochord, eye, somites, and rohon beard neurons. We exposed transgenic zebrafish to simulated-microgravity for different durations at a variety of developmental times in an attemp...

  18. Knowledge internalization and product development in family firms : When relational and affective factors matter

    OpenAIRE

    Chirico, Francesco; Salvato, Carlo

    2016-01-01

    Understanding the forces that support and inhibit product development (PD) in family firms is central to explaining their long-term success and survival. Our study reveals that social capital and relational conflict among family members do not affect PD directly, as existing theory suggests, but only through the internalization of knowledge among family members. In contrast, family members’ affective commitment to the family firm is so powerful that it has both a mediated and a direct effect ...

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

    Directory of Open Access Journals (Sweden)

    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

  20. 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

    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

  1. On the increased risk of developing late-onset epilepsy for patients with major affective disorder

    DEFF Research Database (Denmark)

    Nilsson, Flemming Mørkeberg; Kessing, Lars Vedel; Bolwig, Tom Gert

    2003-01-01

    for the control groups. However, the increased risk seemed to be due to the effect of comorbid alcohol or drug abuse and not to the effect of the affective illness itself. LIMITATIONS: The results only apply to hospitalised patients. Diagnoses are not validated for research purposes. CONCLUSION: Patients...... with a diagnosis of affective disorder have an increased risk of developing epilepsy in later life. In patients with affective disorder, comorbid alcoholism/drug abuse seriously increased the risk of a subsequent diagnosis of epilepsy....

  2. Tooth whitening with hydrogen/carbamide peroxides in association with a CPP-ACP paste at different proportions.

    Science.gov (United States)

    de Vasconcelos, A A M; Cunha, A G G; Borges, B C D; Machado, C T; dos Santos, A J S

    2012-06-01

    Different enhanced peroxide formulations have been developed to overcome mineral loss during tooth whitening. This study investigated the impact on tooth whitening from combining a CPP-ACP paste with home peroxide agents at several proportions. Ninety bovine incisors were randomly allocated into nine groups (n = 10) and exposed to 7.5% hydrogen peroxide (HP), 16% carbamide peroxide (CP), a CPP-ACP paste (Tooth Mousse/MI Paste, GC Corporation, Tokyo, Japan) and blends of HP/CP:MI at three proportions (1:1, 2:1 and 1:2). Tooth whitening was performed for 14 days and its effectiveness was measured by a spectrophotometer utilizing the CIE L*a*b* system (ΔE, ΔL*, Δa* and Δb*). Colour readings were measured at baseline (T0), 7 days of bleaching (T7), 14 days of bleaching (T14) and 7 days after the end of bleaching (T21). Data were analysed by two-way ANOVA for paired averages followed by the Tukey's test and Pearson's correlation at 5%. Although CP produced the greatest colour change (ΔE), all whitening protocols were considered to be effective regardless of the CPP-ACP presence. In general, greater changes in ΔE, ΔL*, Δa* and Δb* were detected at T14, with T21 exhibiting similar results to those at T7. A greater number of strong correlations with ΔE values was found for a* (11/15). Within the limitations of this study, the results indicate that the CPP-ACP paste did not affect tooth whitening efficacy. © 2012 Australian Dental Association.

  3. The Permian reptile Opisthodontosaurus carrolli: a model for acrodont tooth replacement and dental ontogeny.

    Science.gov (United States)

    Haridy, Yara; LeBlanc, Aaron R H; Reisz, Robert R

    2018-03-01

    Continuous tooth replacement is common for tetrapods, but some groups of acrodont lepidosaurs have lost the ability to replace their dentition (monophyodonty). Acrodonty, where the tooth attaches to the apex of the jawbone, is an unusual form of tooth attachment that has been associated with the highly autapomorphic condition of monophyodonty. Beyond Lepidosauria, very little is known about the relationship between acrodonty and monophyodonty in other amniotes. We test for this association with a detailed study of the dentition of Opisthodontosaurus, an unusual Early Permian captorhinid eureptile with acrodont dentition. We provide clear evidence, both histological and morphological, that there were regular tooth replacement events in the lower jaw of Opisthodontosaurus, similar to its captorhinid relatives. Thus, our study of the oldest known amniote with an acrodont dentition shows that acrodonty does not inhibit tooth replacement, and that many of the characteristics assigned to lepidosaurian acrodonty are actually highly derived features of lepidosaurs that have resulted secondarily from a lack of tooth replacement. In the context of reptilian dental evolution, we propose the retention of the simple definition of acrodonty, which only pertains to the relative position of the tooth at the apex of the jaw, where the jaw possesses equal lingual and labial walls. This definition of implantation therefore focuses solely on the spatial relationship between the tooth and the jawbone, and separates this relationship from tooth development and replacement. © 2017 Anatomical Society.

  4. [A tooth or an implant--literature based decision making].

    Science.gov (United States)

    Bar On, H; Sharon, E; Lipovezky-Adler, M; Haramaty, O; Smidt, A

    2014-07-01

    The common use of dental implants in the daily practice led to a profound change in the available treatment strategies. The option of replacing a diagnosed doubtful tooth with an implant has become widely accepted and often used. The prognosis systems in use today are based on the three major disciplines: endodontics, periodontics and prosthodontics. Combining these three may impair and bias the decision making process and increase the tendency to base it on subjective clinical experience and personal preference. Reading and reviewing the relevant literature gives no clear tool for use. Root canal treatment is considered a highly predictable treatment procedure and a treated tooth is affected mainly by the quality and type of the fabricated restoration and the risk of caries. Periodontal treatment followed by a suitable maintenance regimen will likely allow long term tooth survival. When comparing the success rates of natural teeth rehabilitation versus implant supported restorations, it appears that with implants an additional treatment is demanded along the years. This coincides with the fact that to date there is no consensus regarding the extent of perimplantitis and perimucositis that is to be expected around a restored implant. In addition, a peri implant tissue problem or a failure of a dental implant may prove to be more challenging than a failure of a tooth. It is important to remember that a dental implant is made to substitute a missing tooth and it is a treatment modality with known and clear indications for rehabilitation of an edentulous space. The aim of this paper is to review and discuss the various aspects of whether to maintain a compromised or a doubtful tooth or to prefer a treatment modality using dental implants. In conclusion it is advised here, to incorporate the discussed issues in the decision making process towards the most suitable treatment plan.

  5. Strategic considerations in treatment planning: deciding when to treat, extract, or replace a questionable tooth.

    Science.gov (United States)

    Zitzmann, Nicola U; Krastl, Gabriel; Hecker, Hanjo; Walter, Clemens; Waltimo, Tuomas; Weiger, Roland

    2010-08-01

    Prosthodontists face the difficult task of judging the influence and significance of multiple risk factors of periodontal, endodontic, or prosthetic origin that can affect the prognosis of an abutment tooth. The purpose of this review is to summarize the critical factors involved in deciding whether a questionable tooth should be treated and maintained, or extracted and possibly replaced by dental implants. A MEDLINE (PubMed) search of the English, peer-reviewed literature published from 1966 to August 2009 was conducted using different keyword combinations including treatment planning, in addition to decision making, periodontics, endodontics, dental implants, or prosthodontics. Further, bibliographies of all relevant papers and previous review articles were hand searched. Tooth maintenance and the acceptance of risks are suitable when: the tooth is not extensively diseased; the tooth has a high strategic value, particularly in patients with implant contraindications; the tooth is located in an intact arch; and the preservation of gingival structures is paramount. When complete-mouth restorations are planned, the strategic use of dental implants and smaller units (short-span fixed dental prostheses), either tooth- or implant-supported, as well as natural tooth abutments with good prognoses for long-span FDPs, is recommended to minimize the risk of failure of the entire restoration. (c) 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  6. 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

  7. Tracking official development assistance for reproductive health in conflict-affected countries.

    Science.gov (United States)

    Patel, Preeti; Roberts, Bayard; Guy, Samantha; Lee-Jones, Louise; Conteh, Lesong

    2009-06-09

    Reproductive health needs are particularly acute in countries affected by armed conflict. Reliable information on aid investment for reproductive health in these countries is essential for improving the efficiency and effectiveness of aid. The purpose of this study was to analyse official development assistance (ODA) for reproductive health activities in conflict-affected countries from 2003 to 2006. The Creditor Reporting System and the Financial Tracking System databases were the chosen data sources for the study. ODA disbursement for reproductive health activities to 18 conflict-affected countries was analysed for 2003, 2004, 2005, and 2006. An average of US $20.8 billion in total ODA was disbursed annually to the 18 conflict-affected countries between 2003 and 2006, of which US $509.3 million (2.4%) was allocated to reproductive health. This represents an annual average of US $1.30 disbursed per capita in the 18 sampled countries for reproductive health activities. Non-conflict-affected least-developed countries received 53.3% more ODA for reproductive health activities than conflict-affected least-developed countries, despite the latter generally having greater reproductive health needs. ODA disbursed for HIV/AIDS prevention and treatment increased by 119.4% from 2003 to 2006. The ODA disbursed for other direct reproductive health activities declined by 35.9% over the same period. This study provides evidence of inequity in disbursement of reproductive health ODA between conflict-affected countries and non-conflict-affected countries, and between different reproductive health activities. These findings and the study's recommendations seek to support initiatives to make aid financing more responsive to need in the context of armed conflict.

  8. Tracking official development assistance for reproductive health in conflict-affected countries.

    Directory of Open Access Journals (Sweden)

    Preeti Patel

    2009-06-01

    Full Text Available BACKGROUND: Reproductive health needs are particularly acute in countries affected by armed conflict. Reliable information on aid investment for reproductive health in these countries is essential for improving the efficiency and effectiveness of aid. The purpose of this study was to analyse official development assistance (ODA for reproductive health activities in conflict-affected countries from 2003 to 2006. METHODS AND FINDINGS: The Creditor Reporting System and the Financial Tracking System databases were the chosen data sources for the study. ODA disbursement for reproductive health activities to 18 conflict-affected countries was analysed for 2003, 2004, 2005, and 2006. An average of US $20.8 billion in total ODA was disbursed annually to the 18 conflict-affected countries between 2003 and 2006, of which US $509.3 million (2.4% was allocated to reproductive health. This represents an annual average of US $1.30 disbursed per capita in the 18 sampled countries for reproductive health activities. Non-conflict-affected least-developed countries received 53.3% more ODA for reproductive health activities than conflict-affected least-developed countries, despite the latter generally having greater reproductive health needs. ODA disbursed for HIV/AIDS prevention and treatment increased by 119.4% from 2003 to 2006. The ODA disbursed for other direct reproductive health activities declined by 35.9% over the same period. CONCLUSIONS: This study provides evidence of inequity in disbursement of reproductive health ODA between conflict-affected countries and non-conflict-affected countries, and between different reproductive health activities. These findings and the study's recommendations seek to support initiatives to make aid financing more responsive to need in the context of armed conflict.

  9. Self-directed study and carving tooth models for learning tooth morphology: perceptions of students at the University of Aberdeen, Scotland.

    Science.gov (United States)

    Abu Eid, Rasha; Ewan, Keith; Foley, Jennifer; Oweis, Yara; Jayasinghe, Jaya

    2013-09-01

    Tooth morphology has been taught at the University of Aberdeen Dental School, United Kingdom, through self-directed workshops, using online handouts and tooth models. Tooth carving sessions were recently added to introduce manual skills training through learning tooth morphology at an early stage of the dental course. The aim of this study was to assess students' perception of both teaching modalities to evaluate their usefulness and to allow further course development. The subjects of this study were first-year dental students. Students' opinions were sought upon completion of the tooth morphology sessions using a structured questionnaire that investigated their views about the effectiveness of both learning methods. The results suggest that self-directed workshops represent an effective way of learning tooth morphology; however, the students recommended further development of the course to make it more focused. Although students questioned the value of the carving sessions, they agreed that it helped to develop their manual dexterity, which was one of the main objectives of the exercise. Further review and development of the course is required in addition to follow-up of the students' performance in clinical skills to further elucidate any advantages of tooth carving to advocate it as a mode of learning.

  10. Heterospecific exposure affects the development of secondary sexual traits in male zebra finches (Taeniopygia guttata).

    Science.gov (United States)

    Gehrold, Andrea; Leitner, Stefan; Laucht, Silke; Derégnaucourt, Sébastien

    2013-03-01

    In many animal species, social signals can affect the reproductive physiology and behaviour of conspecifics. In a few species that exhibit vocal learning, exposure to conspecific and sometimes heterospecific sounds can also influence their vocal development. Here we show that heterospecific exposure can affect the development of secondary sexual traits of male zebra finches (Taeniopygia guttata). In a first experiment, we trained young males with a passive playback of domesticated canary (Serinus canaria) song. Song playback enhanced the sexual development of the birds: they started to sing during the presentation of a video clip of a female earlier during development and exhibited secondary sexual plumage ornaments faster than males of the control group kept in silence. Two out of five birds exhibited clear evidence of imitation of canary song. In a second experiment, we raised young male finches with young male canaries in pairs until adulthood. Again, the live contact with a heterospecific companion affected the development of plumage ornaments in finches. We also observed some evidences of vocal convergence, both for calls and song. Moreover, young males of both species could recognize the call of their heterospecific companion when adults. These results suggest that heterospecific exposure can affect both the sexual and the vocal development of the zebra finch and can have long lasting effects. This article is part of a Special Issue entitled: insert SI title. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. 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.

  12. 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

  13. Immediate effects of tooth extraction on ridge integrity and dimensions.

    Science.gov (United States)

    Leblebicioglu, Binnaz; Hegde, Rachana; Yildiz, Vedat O; Tatakis, Dimitris N

    2015-11-01

    This study aims to assess possible immediate post-extraction changes in ridge integrity and width. Tooth extractions (53 teeth in 30 adults) were performed following atraumatic techniques. Root trunk and ridge width were measured at the crest level in buccolingual direction. Similarly, socket width and buccal plate thickness were also determined. Pre- and post-extraction buccal plate dehiscence, fenestration, or fracture was recorded. Diameter and length of extracted tooth root were also measured. Multinomial logistic regression was used to reveal relationships between ridge outcome (expanded, stable, or collapsed groups) and assessed tooth/site parameters. Post-extraction, buccal plate fracture developed in 5 (9%), dehiscence in 15 (28%), and complete buccal plate loss in 2 sites (4%). Following extraction, ridge width was expanded in 30 (57%), collapsed in 12 (23%), and remained unchanged in 11 (21%) sites. In most sites (72%), post-extraction socket size was wider than pre-extraction root trunk width (p ridge outcome (expansion or collapse compared to stable) (p ridge integrity is uncommon, while ridge width expansion is a common finding immediately following tooth extraction. The significance of such expansion compared to integrity of socket walls remains to be established. Tooth extraction approaches that preserve ridge integrity are accompanied by mainly ridge expansion in ridge width. The significance of such immediate changes for the long-term ridge outcomes (i.e., effect on bone remodeling especially in relation to buccal bone integrity) needs further investigation.

  14. Tooth injury in anaesthesiology.

    Science.gov (United States)

    de Sousa, José Miguel Brandão Ribeiro; Mourão, Joana Irene de Barros

    2015-01-01

    Dental injury is the most common complication of general anaesthesia and has significant physical, economic and forensic consequences. The aim of this study is to review on the characteristics of dental injury associated with anaesthesiology and existing methods of prevention. In this review, the time of anaesthesia in which the dental injury occurs, the affected teeth, the most frequent type of injury, established risk factors, prevention strategies, protection devices and medico-legal implications inherent to its occurrence are approached. Before initiating any medical procedure that requires the use of classic laryngoscopy, a thorough and detailed pre-aesthetic evaluation of the dental status of the patient is imperative, in order to identify teeth at risk, analyze the presence of factors associated with difficult intubation and outline a prevention strategy that is tailored to the risk of dental injury of each patient. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

  15. Tooth injury in anaesthesiology

    Directory of Open Access Journals (Sweden)

    José Miguel Brandão Ribeiro de Sousa

    2015-12-01

    Full Text Available BACKGROUND AND OBJECTIVES: Dental injury is the most common complication of general anaesthesia and has significant physical, economic and forensic consequences. The aim of this study is to review on the characteristics of dental injury associated with anaesthesiology and existing methods of prevention. CONTENTS: In this review, the time of anaesthesia in which the dental injury occurs, the affected teeth, the most frequent type of injury, established risk factors, prevention strategies, protection devices and medico-legal implications inherent to its occurrence are approached. CONCLUSIONS: Before initiating any medical procedure that requires the use of classic laryngoscopy, a thorough and detailed pre-aesthetic evaluation of the dental status of the patient is imperative, in order to identify teeth at risk, analyze the presence of factors associated with difficult intubation and outline a prevention strategy that is tailored to the risk of dental injury of each patient.

  16. [Tooth injury in anaesthesiology].

    Science.gov (United States)

    Brandão Ribeiro de Sousa, José Miguel; de Barros Mourão, Joana Irene

    2015-01-01

    Dental injury is the most common complication of general anaesthesia and has significant physical, economic and forensic consequences. The aim of this study is to review on the characteristics of dental injury associated with anaesthesiology and existing methods of prevention. In this review, the time of anaesthesia in which the dental injury occurs, the affected teeth, the most frequent type of injury, established risk factors, prevention strategies, protection devices and medico-legal implications inherent to its occurrence are approached. Before initiating any medical procedure that requires the use of classic laryngoscopy, a thorough and detailed pre-aesthetic evaluation of the dental status of the patient is imperative, in order to identify teeth at risk, analyze the presence of factors associated with difficult intubation and outline a prevention strategy that is tailored to the risk of dental injury of each patient. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

  17. Peripheral developing odontoma in newborn. Report of two cases and literature review.

    Science.gov (United States)

    Silva, Alan-Roger S; Carlos-Bregni, Roman; Vargas, Pablo-Agustin; de Almeida, Oslei-Paes; Lopes, Marcio-Ajudarte

    2009-11-01

    Extra-osseous odontogenic tumors are rarely observed. However, it is widely accepted that the remains of odontogenic epithelium entrapped in the oral soft tissues may be a possible source for peripheral odontogenic tumors differentiation. Peripheral developing odontoma is considered exceptionally rare, since few similar cases are described in the English-related literature under diverse nomenclature, such as irregular eruption, ectopic tooth, ectopic soft-tissue mesiodens, ectopic odontoma and extra-osseous tooth germ. Previously reported cases invariably affected children and surgical exploration revealed tooth germs exclusively embedded in the soft tissue without bone involvement. Microscopically, all these cases exhibited developing tooth germs composed of ameloblasts, enamel matrix, odontoblastic layer, dentin and dental papilla and the morphological findings seem to depend on the developmental stage of each tooth germ at discovery. Thus, we believe that it is relevant to report two additional cases that were recently diagnosed in Brazil and Guatemala, focusing on their nomenclature, correct diagnosis and further treatment.

  18. Analysis of factors affecting the development of food crop varieties bred by mutation method in China

    International Nuclear Information System (INIS)

    Wang Zhidong; Hu Ruifa

    2002-01-01

    The research developed a production function on crop varieties developed by mutation method in order to explore factors affecting the development of new varieties. It is found that the research investment, human capital and radiation facilities were the most important factors that affected the development and cultivation area of new varieties through the mutation method. It is concluded that not all institutions involved in the breeding activities using mutation method must have radiation facilities and the national government only needed to invest in those key research institutes, which had strong research capacities. The saved research budgets can be used in the entrusting the institutes that have stronger research capacities with irradiating more breeding materials developed by the institutes that have weak research capacities, by which more opportunities to breed better varieties can be created

  19. Risk factors of osteonecrosis of the jaw after tooth extraction in osteoporotic patients on oral bisphosphonates

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Ho Gui; Hwang, Jae Joon; Lee, Jeong Hee; Kim, Young Hyun; Na, Ji Yeon; Han, Sang Sun [Dept. of Oral and Maxillofacial Radiology, Yonsei University, College of Dentistry, Seoul (Korea, Republic of)

    2017-03-15

    The aim of this study was to investigate the incidence of bisphosphonate-related osteonecrosis of the jaw (BRONJ) after tooth extraction in patients with osteoporosis on oral bisphosphonates in Korea and to evaluate local factors affecting the development of BRONJ. The clinical records of 320 patients who underwent dental extraction while receiving oral bisphosphonates were reviewed. All patients had a healing period of more than 6 months following the extractions. Each patient's clinical record was used to assess the incidence of BRONJ; if BRONJ occurred, a further radiographic investigation was carried out to obtain a more definitive diagnosis. Various local factors including age, gender, extraction site, drug type, duration of administration, and C-terminal telopeptide (CTx) level were retrieved from the patients' clinical records for evaluating their effect on the incidence of BRONJ. Among the 320 osteoporotic patients who underwent tooth extraction, 11 developed BRONJ, reflecting an incidence rate of 3.44%. Out of the local factors that may affect the incidence of BRONJ, gender, drug type, and CTx level showed no statistically significant effects, while statistically significant associations were found for age, extraction site, and duration of administration. The incidence of BRONJ increased with age, was greater in the mandible than the maxilla, and was associated with a duration of administration of more than 3 years. Tooth extraction in patients on oral bisphosphonates requires careful consideration of their age, the extraction site, and the duration of administration, and close postoperative follow-up should be carried out to facilitate effective early management.

  20. Increased Risk of Developing Affective Disorder in Patients with Hypothyroidism: A Register-Based Study

    DEFF Research Database (Denmark)

    Thomsen, Anders F.; Kvist, Tine Kajsa; Andersen, Per Kragh

    2005-01-01

    BACKGROUND: Links between thyroid function and depression have been noted in many contexts. We assessed whether hospitalization with hypothyroidism was a risk factor for developing affective disorder. METHODS: We conducted a prospective cohort study using historical data from Danish registers....... The observational period was 1977-1999. Three study cohorts were identified: all patients with a first hospital admittance with the resulting index discharge diagnoses hypothyroidism, osteoarthritis, or nontoxic goiter. A later hospitalization with a resulting discharge diagnosis of affective disorder was used...... with an increased risk of hospitalization with affective disorder when compared to the control diseases. The risk of hospitalization with affective disorder was greatest in the first year after index hospitalization. CONCLUSION: Patients hospitalized with hypothyroidism have a greater risk of readmission...

  1. Development and initial evaluation of Transdiagnostic Behavior Therapy (TBT) for veterans with affective disorders.

    Science.gov (United States)

    Gros, Daniel F

    2014-12-15

    Considerable attention has focused on the growing need for evidence-based psychotherapy for veterans with affective disorders within the Department of Veteran Affairs. Despite, and possibly due to, the large number of evidence-based protocols available, several obstacles remain in their widespread delivery within Veterans Affairs Medical Centers. In part as an effort to address these concerns, newer transdiagnostic approaches to psychotherapy have been developed to provide a single treatment that is capable of addressing several, related disorders. The goal of the present investigation was to develop and evaluate a transdiagnostic psychotherapy, Transdiagnostic Behavior Therapy (TBT), in veterans with affective disorders. Study 1 provided initial support for transdiagnostic presentation of evidence-based psychotherapy components in veterans with principal diagnoses of affective disorders (n=15). These findings were used to inform the development of the TBT protocol. In Study 2, an initial evaluation of TBT was completed in a second sample of veterans with principal diagnoses of affective disorders (n=29). The findings of Study 2 demonstrated significant improvements in symptoms of depression, anxiety, stress, posttraumatic stress, and related impairment across participants with various principal diagnoses. Together, the investigation provided preliminary support for effectiveness of TBT in veterans with affective disorders. Published by Elsevier Ireland Ltd.

  2. Multiple essential MT1-MMP functions in tooth root formation, dentinogenesis, and tooth eruption.

    Science.gov (United States)

    Xu, H; Snider, T N; Wimer, H F; Yamada, S S; Yang, T; Holmbeck, K; Foster, B L

    2016-01-01

    Membrane-type matrix metalloproteinase 1 (MT1-MMP) is a transmembrane zinc-endopeptidase that breaks down extracellular matrix components, including several collagens, during tissue development and physiological remodeling. MT1-MMP-deficient mice (MT1-MMP(-/-)) feature severe defects in connective tissues, such as impaired growth, osteopenia, fibrosis, and conspicuous loss of molar tooth eruption and root formation. In order to define the functions of MT1-MMP during root formation and tooth eruption, we analyzed the development of teeth and surrounding tissues in the absence of MT1-MMP. In situ hybridization showed that MT1-MMP was widely expressed in cells associated with teeth and surrounding connective tissues during development. Multiple defects in dentoalveolar tissues were associated with loss of MT1-MMP. Root formation was inhibited by defective structure and function of Hertwig's epithelial root sheath (HERS). However, no defect was found in creation of the eruption pathway, suggesting that tooth eruption was hampered by lack of alveolar bone modeling/remodeling coincident with reduced periodontal ligament (PDL) formation and integration with the alveolar bone. Additionally, we identified a significant defect in dentin formation and mineralization associated with the loss of MT1-MMP. To segregate these multiple defects and trace their cellular origin, conditional ablation of MT1-MMP was performed in epithelia and mesenchyme. Mice featuring selective loss of MT1-MMP activity in the epithelium were indistinguishable from wild type mice, and importantly, featured a normal HERS structure and molar eruption. In contrast, selective knock-out of MT1-MMP in Osterix-expressing mesenchymal cells, including osteoblasts and odontoblasts, recapitulated major defects from the global knock-out including altered HERS structure, short roots, defective dentin formation and mineralization, and reduced alveolar bone formation, although molars were able to erupt. These data

  3. Towards tooth friendly soft drinks.

    Science.gov (United States)

    Kolahi, Jafar; Fazilati, Mohamad; Kadivar, Mahdi

    2009-10-01

    Most soft drinks contain high concentration of simple carbohydrates and have a pH of 3 or even lower. Therefore, they are harmful for tooth structure. A tooth friendly soft drink (T.F.S.D) should have the following characteristics and elements; fluoride (approximately 1 ppm), casein phosphopeptide-amorphous calcium phosphate (2%), xylitol (4-6g/serving), tea polyphenols (2-4 mg/ml), cranberry extract (250 mg/ml of the flavonoids quercetin and myricetin), sugar free, pH close to 5.5 and super oxygenation (240,000 ppm) vs. carbonation. T.F.S.D can be packaged in a container which gaseous oxygen is dissolved in a liquid in the form of bubbles. However, looking at opportunities for so-called sophisticated soft drinks, T.F.S.D will be an example for a functional and health oriented soft drink.

  4. Optical spectroscopy and tooth decay

    Science.gov (United States)

    Misra, P.; De, T.; Singh, R.

    2005-11-01

    Optical spectroscopy in the ultraviolet, visible and mid-infrared spectral regions has been used to discriminate between healthy and diseased teeth of patients in the age range 15-75 years. Spectral scans of absorbance versus wavenumber and fluorescence intensity versus wavelength have been recorded and investigated for caries and periodontal disease. Such optical diagnostics can prove very useful in the early detection and treatment of tooth decay.

  5. Use of ribbond and panavia F cement in reattaching fractured tooth fragments of vital maxillary anterior teeth

    Directory of Open Access Journals (Sweden)

    Hemalatha Hiremath

    2012-01-01

    Full Text Available Coronal fractures of the anterior teeth are a common form of dental trauma that mainly affects children and adolescents. One of the options for managing coronal tooth fractures when the tooth fragment is available and there is no or minimal violation of the biological width is the reattachment of the fragment. This article presents a novel technique for reattachment of oblique fractured fragment of vital maxillary central and lateral incisor with pulp exposure. Pulp capping was done using mineral trioxide aggregate. Orthodontic extrusion was done to expose the sub gingival fractured site. Polyethylene fiber (ribbond and panavia F cement were used to reattach the fractured fragment using an internal groove technique to provide high fracture strength to restored tooth. Ribbond fibers can be used to give additional strength to the reattached tooth fragment so that the tooth obtains fracture resistance equal to an intact tooth.

  6. Tooth wear in captive rhinoceroses (Diceros, Rhinoceros, Ceratotherium: Perissodactyla) differs from that of free-ranging conspecifics

    NARCIS (Netherlands)

    Taylor, L.A.; Müller, D.W.H.; Schwitzer, C.; Kaiser, T.M.; Codron, D.; Schulz, E.; Clauss, M.

    2014-01-01

    Tooth wear can affect body condition, reproductive success and life expectancy. Poor dental health is frequently reported in the zoo literature, and abrasion-dominated tooth wear, which is typical for grazers, has been reported in captive browsing ruminants. The aim of this study was to test if a

  7. Bus rapid transit and development : policies and practices that affect development around transit.

    Science.gov (United States)

    2009-12-01

    The development of Bus Rapid Transit (BRT) systems is relatively recent in the United States, but several systems are in operation and more are advancing. There is a need for a more comprehensive understanding of the relationship between land use and...

  8. High-throughput identification of small molecules that affect human embryonic vascular development

    Science.gov (United States)

    Vazão, Helena; Rosa, Susana; Barata, Tânia; Costa, Ricardo; Pitrez, Patrícia R.; Honório, Inês; de Vries, Margreet R.; Papatsenko, Dimitri; Benedito, Rui; Saris, Daniel; Khademhosseini, Ali; Quax, Paul H. A.; Pereira, Carlos F.; Mercader, Nadia; Ferreira, Lino

    2017-01-01

    Birth defects, which are in part caused by exposure to environmental chemicals and pharmaceutical drugs, affect 1 in every 33 babies born in the United States each year. The current standard to screen drugs that affect embryonic development is based on prenatal animal testing; however, this approach yields low-throughput and limited mechanistic information regarding the biological pathways and potential adverse consequences in humans. To develop a screening platform for molecules that affect human embryonic development based on endothelial cells (ECs) derived from human pluripotent stem cells, we differentiated human pluripotent stem cells into embryonic ECs and induced their maturation under arterial flow conditions. These cells were then used to screen compounds that specifically affect embryonic vasculature. Using this platform, we have identified two compounds that have higher inhibitory effect in embryonic than postnatal ECs. One of them was fluphenazine (an antipsychotic), which inhibits calmodulin kinase II. The other compound was pyrrolopyrimidine (an antiinflammatory agent), which inhibits vascular endothelial growth factor receptor 2 (VEGFR2), decreases EC viability, induces an inflammatory response, and disrupts preformed vascular networks. The vascular effect of the pyrrolopyrimidine was further validated in prenatal vs. adult mouse ECs and in embryonic and adult zebrafish. We developed a platform based on human pluripotent stem cell-derived ECs for drug screening, which may open new avenues of research for the study and modulation of embryonic vasculature. PMID:28348206

  9. Factors that Affect Emergent Literacy Development When Engaging with Electronic Books

    Science.gov (United States)

    Salmon, Lynda G.

    2014-01-01

    This article reviews extant literature with the purpose of identifying factors that affect the potential efficacy of electronic books to support literacy development during early childhood. Selection criteria include experimental, quasi-experimental, and observational studies from peer-reviewed journals from 2000 to 2013 with a target population…

  10. Past, present and future morphological development of a tsunami-affected coast

    NARCIS (Netherlands)

    Meilianda, Ella

    2009-01-01

    This thesis investigated a thorough geomorphology of Banda Aceh, a coast on the north tip of Sumatra Island, Indonesia which was severely affected by the earthquake and tsunami occurred on 26 December 2004. The response and development of the Banda Aceh coast before and after the tsunami was thus

  11. Dogs in the Hall: A Case Study of Affective Skill Development in an Urban Veterinary Program

    Science.gov (United States)

    Martin, Michael; Tummons, John; Ball, Anna; Bird, William

    2014-01-01

    The purpose of this bounded single case study was to explore how an urban high school veterinary program impacted students' affective skill development. The program was unique because students were required to participate in internships with local animal care businesses and care for animals within the school veterinary laboratory. The…

  12. The Effect of Differentiation Approach Developed on Creativity of Gifted Students: Cognitive and Affective Factors

    Science.gov (United States)

    Altintas, Esra; Özdemir, Ahmet S.

    2015-01-01

    The aim of the study is to develop a differentiation approach for the mathematics education of gifted middle school students and to determine the effect of the differentiation approach on creative thinking skills of gifted students based on both cognitive and affective factors. In this context, the answer to the following question was searched:…

  13. Does Intellectual Disability Affect the Development of Dental Caries in Patients with Cerebral Palsy?

    Science.gov (United States)

    Moreira, Rafaela Nogueira; Alcantara, Carlos Eduardo Pinto; Mota-Veloso, Isabella; Marinho, Sandra Aparecida; Ramos-Jorge, Maria L.; Oliveira-Ferreira, Fernanda

    2012-01-01

    The aim of this study was to evaluate if the severity of intellectual disability is a factor that affects the development of dental cavities in patients with cerebral palsy. This cross-sectional study was conducted on 165 individuals who were selected from a physical rehabilitation center, a special public school and a regular public school. Of…

  14. The Impact of Some Economic Factors Affecting Groundwater Pollution in Both Developed and Developing Countries

    Directory of Open Access Journals (Sweden)

    H. Biabi

    2016-03-01

    Full Text Available Introduction: The role of economic factors in pollution and environmental degradation is one of the major Issues in economic and environmental studies that many researchers have addressed in their studies. One of the issues in the field of environment to which less attention has been paid is the effect of economic factors such as the openness of the economy on water resource pollution. In this paper we investigate the relation between water pollution and economic factors such as economic size, capital to labor ratio and economic openness in two groups of developed and developing countries with paned data method. In fact we investigate the two hypothesis of Environmental Kuznets curve and pollution havens in two groups of countries. To prevent the pollution of groundwater resources in the process of economic growth, policies must be coordinated by responsible organizations. Changing crop patterns and moving toward the production of organic products to reduce the use of polluting substances in the production of agricultural products is one of these solutions. Materials and Methods: In the present study, using panel data methods, the correlation between some independent economic factors such as per capita GDP, Squared per capita GDP that both indicate Scale effect and capital to labor index with Squared capital to labor index both indicating comparative advantage effect and openness of trade and some composite indices on dependent variables, groundwater pollution, in the two groups of countries both developed and developing countries has been investigated. For this purpose, using the biological oxygen demand index (BOD as an indicator of pollution of groundwater resources and sum of exports and imports divided by GDP as an indicator of economic openness and GDP per capita as an indicator of the economy in the period of 1995 to 2006, the Environmental Kuznets curve and pollution havens hypothesis have been tested. Results Discussion: The issue of

  15. Factors Affecting the Development of ICT Competencies of Teachers in Primary Schools

    OpenAIRE

    Vitanova, Vasilka; Atanasova-Pacemska, Tatjana; Iliev, Dean; Pachemska, Sanja

    2015-01-01

    A research was conducted in order to ensure valid and reliable assessment of the extent of ICT knowledge and skills of teachers in primary schools, to identify the factors in terms of teachers affecting the development of ICT competences, and to identify strategies to improve the development of effectiveness in the future. The research surveyed 220 teachers from 10 primary schools of Macedonia. The Technique SEM was used to determine the relative strength of influence of factors on ICT compet...

  16. Factors Affecting The Use and Development of Solar Energy in Iran's Agricultural Sector

    Directory of Open Access Journals (Sweden)

    Mohsen Mohammadi

    2017-03-01

    Keywords: Agriculture, Renewable Energy, Fossil, Fuel, Sustainability Article History: Received Nov 16th 2016; Received in revised form January 12nd 2017; Accepted 3rd February 2017; Available online How to Cite This Article: Mohammadi, M and Yavari, G. (2017 Factors affecting the use and development of solar energy in Iran's agricultural sector. International Journal of Renewable Energy Development, 6(1,45-53. http://dx.doi.org/10.14710/ijred.6.1.45-53

  17. Retrospective Dosimetry: Dose Analysis From Tooth Enamel Using Electron Spin Resonance (ESR)

    International Nuclear Information System (INIS)

    Mohd Rodzi Ali; Rahimah Abdul Rahim; Noraisyah Yusof; Syed Asraf Fahlawi Wafa Syed Mohd Ghazi; Juliana Mahamad Napiah; Yahaya Talib; Rehir Dahalan

    2014-01-01

    The radiation dose should be accurately measured in order to relate its effect to the cells. The assessment of dose usually performed using biological dosimetry techniques. However, the reduction of lymphocytes (white blood cells) after the time period results in inaccuracy of dose measurement. An alternative method used is the application of Electron Spin Resonance (ESR) using tooth enamel. In this study, tooth enamels were evaluated and used to measure the individual absorbed dose from the background. The basic tooth features that would affect dose measurement were discussed. The results show this technique is capable and effective for retrospective dose measurement and useful for the study of radiation effect to human. (author)

  18. Deiodinase knockdown during early zebrafish development affects growth, development, energy metabolism, motility and phototransduction.

    Directory of Open Access Journals (Sweden)

    Enise Bagci

    Full Text Available Thyroid hormone (TH balance is essential for vertebrate development. Deiodinase type 1 (D1 and type 2 (D2 increase and deiodinase type 3 (D3 decreases local intracellular levels of T3, the most important active TH. The role of deiodinase-mediated TH effects in early vertebrate development is only partially understood. Therefore, we investigated the role of deiodinases during early development of zebrafish until 96 hours post fertilization at the level of the transcriptome (microarray, biochemistry, morphology and physiology using morpholino (MO knockdown. Knockdown of D1+D2 (D1D2MO and knockdown of D3 (D3MO both resulted in transcriptional regulation of energy metabolism and (muscle development in abdomen and tail, together with reduced growth, impaired swim bladder inflation, reduced protein content and reduced motility. The reduced growth and impaired swim bladder inflation in D1D2MO could be due to lower levels of T3 which is known to drive growth and development. The pronounced upregulation of a large number of transcripts coding for key proteins in ATP-producing pathways in D1D2MO could reflect a compensatory response to a decreased metabolic rate, also typically linked to hypothyroidism. Compared to D1D2MO, the effects were more pronounced or more frequent in D3MO, in which hyperthyroidism is expected. More specifically, increased heart rate, delayed hatching and increased carbohydrate content were observed only in D3MO. An increase of the metabolic rate, a decrease of the metabolic efficiency and a stimulation of gluconeogenesis using amino acids as substrates may have been involved in the observed reduced protein content, growth and motility in D3MO larvae. Furthermore, expression of transcripts involved in purine metabolism coupled to vision was decreased in both knockdown conditions, suggesting that both may impair vision. This study provides new insights, not only into the role of deiodinases, but also into the importance of a correct

  19. Deiodinase knockdown during early zebrafish development affects growth, development, energy metabolism, motility and phototransduction.

    Science.gov (United States)

    Bagci, Enise; Heijlen, Marjolein; Vergauwen, Lucia; Hagenaars, An; Houbrechts, Anne M; Esguerra, Camila V; Blust, Ronny; Darras, Veerle M; Knapen, Dries

    2015-01-01

    Thyroid hormone (TH) balance is essential for vertebrate development. Deiodinase type 1 (D1) and type 2 (D2) increase and deiodinase type 3 (D3) decreases local intracellular levels of T3, the most important active TH. The role of deiodinase-mediated TH effects in early vertebrate development is only partially understood. Therefore, we investigated the role of deiodinases during early development of zebrafish until 96 hours post fertilization at the level of the transcriptome (microarray), biochemistry, morphology and physiology using morpholino (MO) knockdown. Knockdown of D1+D2 (D1D2MO) and knockdown of D3 (D3MO) both resulted in transcriptional regulation of energy metabolism and (muscle) development in abdomen and tail, together with reduced growth, impaired swim bladder inflation, reduced protein content and reduced motility. The reduced growth and impaired swim bladder inflation in D1D2MO could be due to lower levels of T3 which is known to drive growth and development. The pronounced upregulation of a large number of transcripts coding for key proteins in ATP-producing pathways in D1D2MO could reflect a compensatory response to a decreased metabolic rate, also typically linked to hypothyroidism. Compared to D1D2MO, the effects were more pronounced or more frequent in D3MO, in which hyperthyroidism is expected. More specifically, increased heart rate, delayed hatching and increased carbohydrate content were observed only in D3MO. An increase of the metabolic rate, a decrease of the metabolic efficiency and a stimulation of gluconeogenesis using amino acids as substrates may have been involved in the observed reduced protein content, growth and motility in D3MO larvae. Furthermore, expression of transcripts involved in purine metabolism coupled to vision was decreased in both knockdown conditions, suggesting that both may impair vision. This study provides new insights, not only into the role of deiodinases, but also into the importance of a correct TH balance

  20. [Assessment of tooth bleaching efficacy with spectrophotometer].

    Science.gov (United States)

    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.

  1. Permanent tooth agenesis in non-syndromic Robin sequence and cleft palate: prevalence and patterns.

    Science.gov (United States)

    de Smalen, Anneline; van Nunen, Daan P F; Hermus, Ruurd R; Ongkosuwito, Edwin M; van Wijk, Arjen J; Griot, J Peter W Don; Breugem, Corstiaan C; Kramer, Gem J C

    2017-09-01

    Partial tooth agenesis is frequently observed in Robin sequence. Tooth anomalies are increasingly considered as an extended phenotype of the cleft palate population. The study objective was to compare the prevalence and patterns of tooth agenesis in a group of patients with non-syndromic Robin sequence (ns-RS) and a group with non-syndromic cleft palate (ns-CP). The panoramic radiographs of 115 ns-RS and 191 ns-CP patients were assessed for agenesis of the permanent dentition (excluding third molars) and the patterns recorded using the Tooth Agenesis Code. Partial tooth agenesis was observed in 47.8% of ns-RS and 29.8% of ns-CP patients with a greater prevalence in the mandibula than in the maxilla, particularly in ns-RS. The teeth most frequently absent in both groups were the mandibular second premolars and maxillary lateral incisors. Tooth agenesis was bilateral in two-thirds of affected ns-RS patients and one-half of ns-CP patients. In ns-RS, bilateral agenesis of the mandibular second premolars was more frequently observed in female than that in male patients. Completely symmetrical patterns of hypodontia were found in around 45% of ns-RS patients with tooth agenesis compared to 35% in ns-CP. No association was found between the extent of the palatal cleft and the severity of hypodontia. Tooth agenesis is more prevalent in ns-RS than that in ns-CP, demonstrates a much greater predilection for the mandible in ns-RS, and bears no relation to the extent of the palatal cleft. When compared to ns-CP, additional developmental disturbances are likely involved in the etiology of tooth agenesis in ns-RS. Future research could help identify the underlying genetic traits and aid in classifying patients in those with and without expected tooth agenesis in order to facilitate orthodontic management strategies.

  2. 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.

  3. 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.

  4. The cracked tooth conundrum: terminology, classification, diagnosis, and management.

    Science.gov (United States)

    Kahler, William

    2008-10-01

    To provide an overview of the clinical features, diagnosis, classification and management of cracked teeth which may be a diagnostic challenge in clinical practice. Cracks may initiate from coronal tooth structure or from within the root and affect healthy or root treated teeth. There are many terminologies and classifications in the literature for cracked teeth that can be as confusing as the array of clinical symptoms which are associated with this condition. The term "cracked tooth syndrome" is misleading as there are a range of symptoms that do not form a distinct and reliable pattern. Symptoms will vary with teeth that have healthy pulps, for teeth with inflamed or necrotic pulps, and for teeth that have been root treated. The American Association of Endodontists have classified five specific variations of cracked teeth; craze line, fractured cusp, cracked tooth, split tooth, and vertical root fracture. The importance of differentiating dentin, pulpal and periodontal pain for diagnosis and treatment for these specific entities will be elaborated. A decision flow chart indicating the treatment options available is presented.

  5. Optimum force magnitude for orthodontic tooth movement: a mathematic model.

    NARCIS (Netherlands)

    Ren, Y.; Maltha, J.C.; Hof, M.A. van 't; Kuijpers-Jagtman, A.M.

    2004-01-01

    The aim of this study was to develop a mathematic model to describe the relationship between magnitude of applied force and rate of orthodontic tooth movement. Initially, data were extracted from experimental studies in dogs (beagles), in which controlled, standardized forces were used to move

  6. De novo PMP2 mutations in families with type 1 Charcot-Marie-Tooth disease.

    Science.gov (United States)

    Motley, William W; Palaima, Paulius; Yum, Sabrina W; Gonzalez, Michael A; Tao, Feifei; Wanschitz, Julia V; Strickland, Alleene V; Löscher, Wolfgang N; De Vriendt, Els; Koppi, Stefan; Medne, Livija; Janecke, Andreas R; Jordanova, Albena; Zuchner, Stephan; Scherer, Steven S

    2016-06-01

    We performed whole exome sequencing on a patient with Charcot-Marie-Tooth disease type 1 and identified a de novo mutation in PMP2, the gene that encodes the myelin P2 protein. This mutation (p.Ile52Thr) was passed from the proband to his one affected son, and segregates with clinical and electrophysiological evidence of demyelinating neuropathy. We then screened a cohort of 136 European probands with uncharacterized genetic cause of Charcot-Marie-Tooth disease and identified another family with Charcot-Marie-Tooth disease type 1 that has a mutation affecting an adjacent amino acid (p.Thr51Pro), which segregates with disease. Our genetic and clinical findings in these kindred demonstrate that dominant PMP2 mutations cause Charcot-Marie-Tooth disease type 1. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Effect of neonatal capsaicin treatment on orthodontic tooth movement in male Sprague-Dawley rats.

    Science.gov (United States)

    Davila, Julian E; Miller, James R; Hodges, James S; Beyer, John P; Larson, Brent E

    2011-04-01

    In this study, we examined the effect of neonatal administration of capsaicin on the magnitude of orthodontic tooth movement in rats. Twelve timed pregnant Sprague-Dawley rats were randomized between the capsaicin group and the vehicle group. The pups received treatment with either capsaicin or vehicle on day 2 of life. Capsaicin treatment has been shown to produce a selective destruction of fine myelinated and unmyelinated Aδ and C sensory nerve fibers, causing an inhibition of the effects from neurogenic inflammation. Tooth-movement experiments began at 12 weeks of age. A mesial tipping force was applied to the maxillary first molar by using a 3-mm length of Sentalloy closed-coil spring (Dentsply GAC Intl, Bohemia, NY) activated from a bonded molar cleat to the maxillary incisors; this appliance delivers a constant tipping force of 50 g. Diastema measurements between the first and second molars were made at 2 and 4 weeks after appliance placement. Measurements were made indirectly from stone models by using a charge-coupled device microscope camera and Optimas 5.2 measurement software (Media Cybernetics, Bethesda, Md). Two-way repeated-measures analysis of variance (ANOVA) was used to analyze the differences between the groups. The capsaicin-treated rats and the controls did not differ in the amount of tooth movement at the collected time points (P >0.05). Similarly, the magnitude of change of tooth movement from 2 to 4 weeks did not differ between the groups (P >0.05). An increase in average diastema size was observed between 2 and 4 weeks after appliance activation in both treatment groups (P <0.0001). These results suggest that neonatal capsaicin desensitization in the rat does not affect the rate of orthodontic tooth movement after the application of a 50-g tipping force to the maxillary first molar. This might be due in part to the development of compensatory mechanisms in the chronically desensitized rat. Further studies are necessary to determine the

  8. Factors Affecting The Career Development Of Employees In Secretariat Office Of City Samarinda

    Directory of Open Access Journals (Sweden)

    Santi Rande

    2015-03-01

    Full Text Available ABSTRACT Although the primary responsibility for career planning lies in the individual but organizational career planning should be completely in line with individual career planning if an organization wants to retain the best employees. Assumptions and the perspective delivers the researchers to examine the influence of aspects of individual and organizational aspects of the career development of employees within the organization of government. The population in this study were employees of the Regional Secretariat of Samarinda by sampling using Proportional Sampling. This research uses a quantitative approach to the explanation that the format is done through surveys. The results showed that the main factors affecting the career development of staff at the Regional Secretariat Samarinda is a factor of career counseling performance appraisal and career mapping which affects the employees career development is partially respectively or simultaneously together .

  9. Anthropogenic changes in sodium affect neural and muscle development in butterflies

    Science.gov (United States)

    Snell-Rood, Emilie C.; Espeset, Anne; Boser, Christopher J.; White, William A.; Smykalski, Rhea

    2014-01-01

    The development of organisms is changing drastically because of anthropogenic changes in once-limited nutrients. Although the importance of changing macronutrients, such as nitrogen and phosphorus, is well-established, it is less clear how anthropogenic changes in micronutrients will affect organismal development, potentially changing dynamics of selection. We use butterflies as a study system to test whether changes in sodium availability due to road salt runoff have significant effects on the development of sodium-limited traits, such as neural and muscle tissue. We first document how road salt runoff can elevate sodium concentrations in the tissue of some plant groups by 1.5–30 times. Using monarch butterflies reared on roadside- and prairie-collected milkweed, we then show that road salt runoff can result in increased muscle mass (in males) and neural investment (in females). Finally, we use an artificial diet manipulation in cabbage white butterflies to show that variation in sodium chloride per se positively affects male flight muscle and female brain size. Variation in sodium not only has different effects depending on sex, but also can have opposing effects on the same tissue: across both species, males increase investment in flight muscle with increasing sodium, whereas females show the opposite pattern. Taken together, our results show that anthropogenic changes in sodium availability can affect the development of traits in roadside-feeding herbivores. This research suggests that changing micronutrient availability could alter selection on foraging behavior for some roadside-developing invertebrates. PMID:24927579

  10. Anthropogenic changes in sodium affect neural and muscle development in butterflies.

    Science.gov (United States)

    Snell-Rood, Emilie C; Espeset, Anne; Boser, Christopher J; White, William A; Smykalski, Rhea

    2014-07-15

    The development of organisms is changing drastically because of anthropogenic changes in once-limited nutrients. Although the importance of changing macronutrients, such as nitrogen and phosphorus, is well-established, it is less clear how anthropogenic changes in micronutrients will affect organismal development, potentially changing dynamics of selection. We use butterflies as a study system to test whether changes in sodium availability due to road salt runoff have significant effects on the development of sodium-limited traits, such as neural and muscle tissue. We first document how road salt runoff can elevate sodium concentrations in the tissue of some plant groups by 1.5-30 times. Using monarch butterflies reared on roadside- and prairie-collected milkweed, we then show that road salt runoff can result in increased muscle mass (in males) and neural investment (in females). Finally, we use an artificial diet manipulation in cabbage white butterflies to show that variation in sodium chloride per se positively affects male flight muscle and female brain size. Variation in sodium not only has different effects depending on sex, but also can have opposing effects on the same tissue: across both species, males increase investment in flight muscle with increasing sodium, whereas females show the opposite pattern. Taken together, our results show that anthropogenic changes in sodium availability can affect the development of traits in roadside-feeding herbivores. This research suggests that changing micronutrient availability could alter selection on foraging behavior for some roadside-developing invertebrates.

  11. 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.

  12. Three dimensional mathematical model of tooth for finite element analysis

    Directory of Open Access Journals (Sweden)

    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.

  13. [Three dimensional mathematical model of tooth for finite element analysis].

    Science.gov (United States)

    Puskar, Tatjana; Vasiljević, Darko; Marković, Dubravka; Jevremović, Danimir; Pantelić, Dejan; Savić-Sević, Svetlana; Murić, Branka

    2010-01-01

    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. Forming the mathematical model of abutment of the second upper premolar for finite element analysis of stress and deformation of dental structures. The abutment tooth has a form of a complex geometric object. It is suitable for modeling in programs for solid modeling SolidWorks. After analysing 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. 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. 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.

  14. Materials chemistry: A synthetic enamel for rapid tooth repair

    Science.gov (United States)

    Yamagishi, Kazue; Onuma, Kazuo; Suzuki, Takashi; Okada, Fumio; Tagami, Junji; Otsuki, Masayuki; Senawangse, Pisol

    2005-02-01

    The conventional treatment of dental caries involves mechanical removal of the affected part and filling of the hole with a resin or metal alloy. But this method is not ideal for tiny early lesions because a disproportionate amount of healthy tooth must be removed to make the alloy or resin stick. Here we describe a dental paste of synthetic enamel that rapidly and seamlessly repairs early caries lesions by nanocrystalline growth, with minimal wastage of the natural enamel.

  15. Intentional replantation of periodontally compromised hopeless tooth

    Science.gov (United States)

    Nagappa, G.; Aspalli, Shivanand; Devanoorkar, Archana; Shetty, Sudhir; Parab, Prachi

    2013-01-01

    Aesthetic considerations have influenced the management of dental maladies in varying degrees for many years. Even single tooth mal-alignment makes the patient to approach a dentist. Intentional replantation is a procedure in which an intentional tooth extraction is performed followed by reinsertion of the extracted tooth. Many authors agree that it should be reserved as the last resort to save a tooth after other procedures have failed or would likely to fail. The main reason of failure in replanted teeth is root resorption, specifically ankylosis or replacement resorption. Although the success rate is not always high, intentional replantation may be a treatment alternative that deserves consideration to maintain the natural dentition and avoid extraction of the tooth. Here is case report of a patient desiring alignment of malpositioned periodontally involved anterior single tooth due to various causes treated by intentional replantation. PMID:24174765

  16. Intentional replantation of periodontally compromised hopeless tooth

    Directory of Open Access Journals (Sweden)

    G Nagappa

    2013-01-01

    Full Text Available Aesthetic considerations have influenced the management of dental maladies in varying degrees for many years. Even single tooth mal-alignment makes the patient to approach a dentist. Intentional replantation is a procedure in which an intentional tooth extraction is performed followed by reinsertion of the extracted tooth. Many authors agree that it should be reserved as the last resort to save a tooth after other procedures have failed or would likely to fail. The main reason of failure in replanted teeth is root resorption, specifically ankylosis or replacement resorption. Although the success rate is not always high, intentional replantation may be a treatment alternative that deserves consideration to maintain the natural dentition and avoid extraction of the tooth. Here is case report of a patient desiring alignment of malpositioned periodontally involved anterior single tooth due to various causes treated by intentional replantation.

  17. Intentional replantation of periodontally compromised hopeless tooth.

    Science.gov (United States)

    Nagappa, G; Aspalli, Shivanand; Devanoorkar, Archana; Shetty, Sudhir; Parab, Prachi

    2013-09-01

    Aesthetic considerations have influenced the management of dental maladies in varying degrees for many years. Even single tooth mal-alignment makes the patient to approach a dentist. Intentional replantation is a procedure in which an intentional tooth extraction is performed followed by reinsertion of the extracted tooth. Many authors agree that it should be reserved as the last resort to save a tooth after other procedures have failed or would likely to fail. The main reason of failure in replanted teeth is root resorption, specifically ankylosis or replacement resorption. Although the success rate is not always high, intentional replantation may be a treatment alternative that deserves consideration to maintain the natural dentition and avoid extraction of the tooth. Here is case report of a patient desiring alignment of malpositioned periodontally involved anterior single tooth due to various causes treated by intentional replantation.

  18. Diagnosis and treatment planning: cracked tooth.

    Science.gov (United States)

    Rivera, Eric M; Williamson, Anne

    2003-03-01

    This article discusses the cracked tooth, one of the five major classifications of longitudinal tooth fractures: 1) craze line; 2) cuspal fracture; 3) cracked tooth; 4) split tooth; and 5) vertical root fracture. The term "longitudinal tooth fracture" was first introduced by Rivera (Personal Communication, Iowa City, IA, 1996) and has two meanings. The first implies distance (length), particularly in the vertical (occlusal-cervical) plane, as illustrated by longitudinal lines on a map. The second indicates that these fractures occur over a period of time. Therefore, the term longitudinal tooth fracture applies to fractures that have both a distance and a time component. Thus, fractures are described that are not related to impact trauma (which occurs primarily in incisors), in which the distance (length) component may be similar, but is immediate instead of over a period of time.

  19. Test Tube Tooth: The Next Big Thing.

    Science.gov (United States)

    Yadav, Preeti; Tahir, Mohammed; Yadav, Harsh; Sureka, Rakshit; Garg, Aarti

    2016-06-01

    Unlike some vertebrates and fishes, humans do not have the capacity for tooth regeneration after the loss of permanent teeth. Although artificial replacement with removable dentures, fixed prosthesis and implants is possible through advances in the field of prosthetic dentistry, it would be ideal to recreate a third set of natural teeth to replace lost dentition. For many years now, researchers in the field of tissue engineering have been trying to bioengineer dental tissues as well as whole teeth. In order to attain a whole tooth through dental engineering, that has the same or nearly same biological, mechanical and physical properties of a natural tooth, it's necessary to deal with all the cells and tissues which are concerned with the formation, maintenance and repair of the tooth. In this article we review the steps involved in odontogenesis or organogenesis of a tooth and progress in the bioengineering of a whole tooth.

  20. Effect of repeated immersion solution cycles on the color stability of denture tooth acrylic resins

    OpenAIRE

    Paulo Maurício Batista da Silva; Emílio José Tabaré Rodríguez Acosta; Matheus Jacobina; Luciana de Rezende Pinto; Vinícius Carvalho Porto

    2011-01-01

    OBJECTIVE: Chemical solutions have been widely used for disinfection of dentures, but their effect on color stability of denture tooth acrylic resins after repeated procedures is still unclear. The aim of this in vitro study was to evaluate whether repeated cycles of chemical disinfectants affected the color stability of two denture tooth acrylic resins. MATERIAL AND METHODS: Sixty disc-shaped specimens (40 mm x 3 mm) were fabricated from two different brands (Artiplus and Trilux) of denture ...

  1. Remineralization of primary tooth enamel from individuals with Down syndrome.

    Science.gov (United States)

    Okamoto, Takuma; Shibata, Munenori; Tsuboi, Shinji; Nakagaki, Haruo; Fukuta, Osamu; Kusabe, Yoshitaka; Inukai, Junko

    2011-01-01

    The purpose of this study was to clarify the characteristics of primary tooth enamel of Down syndrome patients (DSPs). We examined 9 primary teeth of Down syndrome children and 11 primary teeth of normally developed children to investigate the remineralization processes of enamel by transverse microradiography and X ray micro analyzer (XMA). Mineral loss, lesion depth, maximum mineral value, minimum mineral value, depth of maximum mineral value, and depth of minimum mineral value were used to analyze transverse microradiography (TMR). In addition, we calculated the percentage of enamel remineralization. All the parameters in the 2 groups showed marked recovery. The results indicated that the Down syndrome group was significantly remineralized the same way as the control group. According to the comparison of mineral content distribution by XMA, the content distribution of magnesium was different between the 2 groups. While recovery through remineralization of primary teeth was similar between Down syndrome children and normally developed children, the mechanism of remineralization process may be different between the 2 groups; consequently, magnesium may be considered as one of the factors affecting recovery.

  2. 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.

  3. Hippo pathway/Yap regulates primary enamel knot and dental cusp patterning in tooth morphogenesis.

    Science.gov (United States)

    Kwon, Hyuk-Jae Edward; Li, Liwen; Jung, Han-Sung

    2015-11-01

    The shape of an individual tooth crown is primarily determined by the number and arrangement of its cusps, i.e., cusp patterning. Enamel knots that appear in the enamel organ during tooth morphogenesis have been suggested to play important roles in cusp patterning. Animal model studies have shown that the Hippo pathway effector Yap has a critical function in tooth morphogenesis. However, the role of the Hippo pathway/Yap in cusp patterning has not been well documented and its specific roles in tooth morphogenesis remain unclear. Here, we provide evidence that Yap is a key mediator in tooth cusp patterning. We demonstrate a correlation between Yap localization and cell proliferation in developing tooth germs. We also show that, between the cap stage and bell stage, Yap is crucial for the suppression of the primary enamel knot and for the patterning of secondary enamel knots, which are the future cusp regions. When Yap expression is stage-specifically knocked down during the cap stage, the activity of the primary enamel knot persists into the bell-stage tooth germ, leading to ectopic cusp formation. Our data reveal the importance of the Hippo pathway/Yap in enamel knots and in the proper patterning of tooth cusps.

  4. 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.

  5. 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)

  6. Cracked tooth syndrome: Overview of literature

    OpenAIRE

    Hasan, Shamimul; Singh, Kuldeep; Salati, Naseer

    2015-01-01

    Pain is defined as an ?unpleasant sensory and emotional feeling which is associated with actual or potential injury of tissue or expressed in terms of such injury.? Tooth pain usually refers to pain around the teeth or jaws mainly as a result of a dental condition. Mostly, toothaches are caused by a carious cavity, a broken tooth, an exposed tooth root or gum disease. The toothache may sometimes be the result of radiating pain from structures in the vicinity of tooth and jaws (cardiac pain, e...

  7. Wnt signaling during tooth replacement in zebrafish (Danio rerio: pitfalls and perspectives

    Directory of Open Access Journals (Sweden)

    Ann eHuysseune

    2014-10-01

    Full Text Available The canonical (β-catenin dependent Wnt signaling pathway has emerged as a likely candidate for regulating tooth replacement in continuously renewing dentitions. So far, the involvement of canonical Wnt signaling has been experimentally demonstrated predominantly in amniotes. These studies tend to show stimulation of tooth formation by activation of the Wnt pathway, and inhibition of tooth formation when blocking the pathway. Here, we report a strong and dynamic expression of the soluble Wnt inhibitor dickkopf1 (dkk1 in developing zebrafish (Danio rerio tooth germs, suggesting an active repression of Wnt signaling during morphogenesis and cytodifferentiation of a tooth, and derepression of Wnt signaling during start of replacement tooth formation. To further analyse the role of Wnt signaling, we used different gain-of-function approaches. These yielded disjunct results, yet none of them indicating enhanced tooth replacement. Thus, masterblind (mbl mutants, defective in axin1, mimic overexpression of Wnt, but display a normally patterned dentition in which teeth are replaced at the appropriate times and positions. Activating the pathway with LiCl had variable outcomes, either resulting in the absence, or the delayed formation, of first-generation teeth, or yielding a regular dentition with normal replacement, but no supernumerary teeth or accelerated tooth replacement.The failure so far to influence tooth replacement in the zebrafish by perturbing Wnt signaling is discussed in the light of (i potential technical pitfalls related to dose- or time-dependency, (ii the complexity of the canonical Wnt pathway, and (iii species-specific differences in the nature and activity of pathway components. Finally, we emphasize the importance of in-depth knowledge of the wild-type pattern for reliable interpretations. It is hoped that our analysis can be inspiring to critically assess and elucidate the role of Wnt signaling in tooth development in polyphyodonts.

  8. Affective strategies, attitudes, and a model of speaking performance development for engineering students

    Science.gov (United States)

    Wijirahayu, S.; Dorand, P.

    2018-01-01

    Learning English as a Foreign language (EFL) as one of the challenges especially for students majoring in Telecommunication Engineering to develop their communication skill as a professional could be one of the chances for them to face a more global era. Yet, there are important factors that may influence the progress of the speaking performance and attitude is one of them. Therefore, a survey involving two main psychological variables in language learning namely attitude and affective strategies and the third variable is speaking performance was conducted and a model of affective strategies in language learning developing through the application of Content Language Integrated Learning and multimedia instruction was introduced. This study involved 71 sophomore students and two classes of university students majoring in Telecommunication Engineering and Electrical Engineering. The researchers used both survey and action research method with quantitative as well as qualitative in approach.

  9. How does blastomere removal affect embryonic development? : A time-lapse analysis

    DEFF Research Database (Denmark)

    Kirkegaard, Kirstine; Hindkjær, Johnny Juhl; Ingerslev, Hans Jakob

    Introduction: Preimplantation genetic diagnosis (PGD) is offered to couples whose potential offspring are at risk of an inherited single gene disease or structural chromosomal disorder. PGD requires embryonic DNA for establishing the diagnosis, which can be obtained by performing blastomere biopsy...... of the 6-10 cell embryo. It has been argued that blastomere removal does not affect embryonic development, but few studies have focussed on safety of the procedure. Recently, time-lapse studies on mice have suggested that blastomere removal affects embryonic development. The present study was conducted...... at the same time-point as the control group, but had a significantly smaller size (p=0,000) and a thicker zona pellucida (p=0,000) when hatching. In the control group expansion of the blastocyst caused continous thinning of zona pellucida until the blastocyst hatched. In the biopsed group no expansion or zona...

  10. 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.

  11. Tooth engineering: searching for dental mesenchymal cells sources.

    Directory of Open Access Journals (Sweden)

    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.

  12. Effects of alendronate on tooth eruption and molar root formation in young growing rats.

    Science.gov (United States)

    Bradaschia-Correa, Vivian; Massa, Luciana F; Arana-Chavez, Victor E

    2007-12-01

    Tooth eruption consists of the movement of teeth from the bony crypt in which they initiate their development to the occlusal plane in the oral cavity. Interactions between the tooth germ and its surrounding alveolar bone occur in order to offer spatial conditions for its development and eruption. This involves bone remodeling during which resorption is a key event. Bisphosphonates are a group of drugs that interfere with the resorption of mineralized tissues. With the purpose of investigating the effects of sodium alendronate (a potent bisphosphonate inhibitor of osteoclast activity) on alveolar bone during tooth development and eruption, we gave newborn rats daily doses of this drug for 4, 14, and 30 days. Samples of the maxillary alveolar process containing the tooth germs were processed for light, transmission, and scanning electron microscopy and were also submitted to tartrate-resistant acid phosphatase histochemistry and high-resolution colloidal-gold immunolabeling for osteopontin. Inhibition of osteoclast activity by sodium alendronate caused the absence of tooth eruption. The lack of alveolar bone remodeling resulted in primary bone with the presence of latent osteoclasts and abundant osteopontin at the interfibrillar regions. The developing bone trabeculae invaded the dental follicle and reached the molar tooth germs, provoking deformities in enamel surfaces. No root formation was observed. These findings suggested that alendronate effectively inhibited tooth eruption by interfering with the activation of osteoclasts, which remained in a latent stage.

  13. Identifying the sociological implications of the main aspects affecting the optimal sporting career development

    OpenAIRE

    2014-01-01

    M.Phil. (Sport Management) This study is strengthened by several studies that have indicated that the dualist nature of student-athletes is problematic, as well as the management thereof. The study aimed to identify the sociological implications of the main aspects affecting the optimal sporting career development in athletics (throwers) at University of Johannesburg Sport, and offers recommendations for managing student-athletes. The methods utilized for this study included: i) self-desig...

  14. Key Factors Affecting Construction Safety Performance in Developing Countries: Evidence from Cambodia

    OpenAIRE

    Durdyev, Serdar; Mohamed, Sherif; Lay, Meng Leang; Ismail, Syuhaida

    2017-01-01

    Although proper safety management in construction is of utmost importance; anecdotal evidence suggests that safety is not adequately considered in many developing countries. This paper considers the key variables affecting construction safety performance in Cambodia. Using an empirical questionnaire survey targeting local construction professionals, respondents were invited to rate the level of importance of 30 variables identified from the seminal literature. The data set was subjected to f...

  15. Selected Factors Affecting the Development of Auditing Services Market in Poland

    OpenAIRE

    Rafał Rydzak

    2010-01-01

    This article presents three factors affecting the development of auditing services market and its oligopoly. The binding provisions of law concerning discretionary powers of auditing companies’ proprietary rights, to some extent, petrify the current auditing market structure. By means of numerous capital access deterrents they make it impossible to compete with the most influential entities on the market. Bearing in mind the vital influence of statutory auditors on companies’ functioning, and...

  16. ARTIE: An Integrated Environment for the Development of Affective Robot Tutors.

    Science.gov (United States)

    Imbernón Cuadrado, Luis-Eduardo; Manjarrés Riesco, Ángeles; De La Paz López, Félix

    2016-01-01

    Over the last decade robotics has attracted a great deal of interest from teachers and researchers as a valuable educational tool from preschool to highschool levels. The implementation of social-support behaviors in robot tutors, in particular in the emotional dimension, can make a significant contribution to learning efficiency. With the aim of contributing to the rising field of affective robot tutors we have developed ARTIE (Affective Robot Tutor Integrated Environment). We offer an architectural pattern which integrates any given educational software for primary school children with a component whose function is to identify the emotional state of the students who are interacting with the software, and with the driver of a robot tutor which provides personalized emotional pedagogical support to the students. In order to support the development of affective robot tutors according to the proposed architecture, we also provide a methodology which incorporates a technique for eliciting pedagogical knowledge from teachers, and a generic development platform. This platform contains a component for identiying emotional states by analysing keyboard and mouse interaction data, and a generic affective pedagogical support component which specifies the affective educational interventions (including facial expressions, body language, tone of voice,…) in terms of BML (a Behavior Model Language for virtual agent specification) files which are translated into actions of a robot tutor. The platform and the methodology are both adapted to primary school students. Finally, we illustrate the use of this platform to build a prototype implementation of the architecture, in which the educational software is instantiated with Scratch and the robot tutor with NAO. We also report on a user experiment we carried out to orient the development of the platform and of the prototype. We conclude from our work that, in the case of primary school students, it is possible to identify, without

  17. ARTIE: an Integrated Environment for the development of Affective Robot Tutors

    Directory of Open Access Journals (Sweden)

    Luis-Eduardo Imbernón Cuadrado

    2016-08-01

    Full Text Available Over the last decade robotics has attracted a great deal of interest from teachers and researchers as a valuable educational tool from preschool to highschool levels. The implementation of social- support behaviours in robot tutors, in particular in the emotional dimension, can make a signicant contribution to learning efciency.With the aim of contributing to the rising eld of affective robot tutors we have developed ARTIE (Affective Robot Tutor Integrated Environment. We offer an architectural pattern which integrates any given educational software for primary school children with a component whose function is to identify the emotional state of the students who are interacting with the software, and with the driver of a robot tutor which provides personalized emotional pedagogical support to the students. In order to support the development of affective robot tutors according to the proposed architecture, we also provide a methodology which incorporates a technique for eliciting pedagogical knowledge from teachers, and a generic development platform. This platform contains a component for identiying emotional states by analysing keyboard and mouse interaction data, and a generic affective pedagogical support component which specifies the affective educational interventions (including facial expressions, body language, tone of voice,... in terms of BML (a Behavior Model Language for virtual agent specification files which are translated into actions of a robot tutor. The platform and the methodology are both adapted to primary school students. Finally, we illustrate the use of this platform to build a prototype implementation of the architecture, in which the educational software is instantiated with Scratch and the robot tutor with NAO. We also report on a user experiment we carried out to orient the development of the platform and of the prototype. We conclude from our work that, in the case of primary school students, it is possible to

  18. ARTIE: An Integrated Environment for the Development of Affective Robot Tutors

    Science.gov (United States)

    Imbernón Cuadrado, Luis-Eduardo; Manjarrés Riesco, Ángeles; De La Paz López, Félix

    2016-01-01

    Over the last decade robotics has attracted a great deal of interest from teachers and researchers as a valuable educational tool from preschool to highschool levels. The implementation of social-support behaviors in robot tutors, in particular in the emotional dimension, can make a significant contribution to learning efficiency. With the aim of contributing to the rising field of affective robot tutors we have developed ARTIE (Affective Robot Tutor Integrated Environment). We offer an architectural pattern which integrates any given educational software for primary school children with a component whose function is to identify the emotional state of the students who are interacting with the software, and with the driver of a robot tutor which provides personalized emotional pedagogical support to the students. In order to support the development of affective robot tutors according to the proposed architecture, we also provide a methodology which incorporates a technique for eliciting pedagogical knowledge from teachers, and a generic development platform. This platform contains a component for identiying emotional states by analysing keyboard and mouse interaction data, and a generic affective pedagogical support component which specifies the affective educational interventions (including facial expressions, body language, tone of voice,…) in terms of BML (a Behavior Model Language for virtual agent specification) files which are translated into actions of a robot tutor. The platform and the methodology are both adapted to primary school students. Finally, we illustrate the use of this platform to build a prototype implementation of the architecture, in which the educational software is instantiated with Scratch and the robot tutor with NAO. We also report on a user experiment we carried out to orient the development of the platform and of the prototype. We conclude from our work that, in the case of primary school students, it is possible to identify, without

  19. Microradiographic investigations on experimentally provoked structural alterations in hard tooth tissues after sealing with plastic material in places where caries is apt to develop

    International Nuclear Information System (INIS)

    Falten, E.

    1981-01-01

    The aim of the present investigation was, after sealing three areas in extracted human teeth: fissures, dental necksand approximate areas and subsequent exposure to experimentally produced cariogenous noxae, to establish possible alterations in the area of transition between sealed and unsealed dental enamal. This would provide a further decision-taking aid with regard to the question whether also the remaining parts where caries is apt to develop should be sealed. (orig./MG) [de

  20. Parents and early life environment affect behavioral development of laying hen chickens.

    Directory of Open Access Journals (Sweden)

    Elske N de Haas

    Full Text Available Severe feather pecking (SFP in commercial laying hens is a maladaptive behavior which is associated with anxiety traits. Many experimental studies have shown that stress in the parents can affect anxiety in the offspring, but until now these effects have been neglected in addressing the problem of SFP in commercially kept laying hens. We therefore studied whether parental stock (PS affected the development of SFP and anxiety in their offspring. We used flocks from a brown and white genetic hybrid because genetic background can affect SFP and anxiety. As SFP can also be influenced by housing conditions on the rearing farm, we included effects of housing system and litter availability in the analysis. Forty-seven rearing flocks, originating from ten PS flocks were followed. Behavioral and physiological parameters related to anxiety and SFP were studied in the PS at 40 weeks of age and in the rearing flocks at one, five, ten and fifteen weeks of age. We found that PS had an effect on SFP at one week of age and on anxiety at one and five weeks of age. In the white hybrid, but not in the brown hybrid, high levels of maternal corticosterone, maternal feather damage and maternal whole-blood serotonin levels showed positive relations with offsprings' SFP at one week and offsprings' anxiety at one and five weeks of age. Disruption and limitation of litter supply at an early age on the rearing farms increased SFP, feather damage and fearfulness. These effects were most prominent in the brown hybrid. It appeared that hens from a brown hybrid are more affected by environmental conditions, while hens from a white hybrid were more strongly affected by parental effects. These results are important for designing measures to prevent the development of SFP, which may require a different approach in brown and white flocks.

  1. DIET EFFECT ON TOOTH DECAY WITH INDEX KPE EVALUATION IN BLANSKO

    OpenAIRE

    VAŠÍČKOVÁ, Pavlína

    2009-01-01

    Regular development of our teeth is the result of reciprocal induction processes with continual development stages. The non-interrupted development of the organism is the basic precondition of healthy dental tissues. It is, therefore, necessary to be aware of the fact that everybody takes on full responsibility for their own health. If we want to have clean and healthy teeth without tooth ache, oulitis and other problems we must take proper dental care. Tooth decay is the most widespread dise...

  2. Conceptualizing Student Affect for Science and Technology at the Middle School Level: Development and Implementation of a Measure of Affect in Science and Technology (MAST)

    Science.gov (United States)

    Romine, William L.; Sadler, Troy D.; Wulff, Eric P.

    2017-10-01

    We describe the development of the Measure of Affect in Science and Technology (MAST), and study its usefulness for measuring science affect in middle school students via both classical and Rasch measurement perspectives. We then proceed to utilize the measurement structure of the MAST to understand how middle school students at varying levels of affect express their interest and attitudes toward science and technology and gender differences in how students express their affect. We found that affect in science and technology comprises a main dimension, science interest, and four peripheral dimensions: interest in careers in science and technology, attitudes toward science, and interest in attending science class. Of these, careers in science and technology carry the highest affective demand. While males showed higher levels of personal and situational interest in science, a greater interest in careers in science and technology was the biggest contributor to males' higher affect toward science and technology. We argue that whether the MAST is used as a measure of a single construct or multiple subconstructs depends upon specific research or evaluation goals; however, both uses of the MAST yield measures which produce valid inferences for student affect.

  3. Nutritional deficits during early development affect hippocampal structure and spatial memory later in life.

    Science.gov (United States)

    Pravosudov, Vladimir V; Lavenex, Pierre; Omanska, Alicja

    2005-10-01

    Development rates vary among individuals, often as a result of direct competition for food. Survival of young might depend on their learning abilities, but it remains unclear whether learning abilities are affected by nutrition during development. The authors demonstrated that compared with controls, 1-year-old Western scrub jays (Aphelocoma californica) that experienced nutritional deficits during early posthatching development had smaller hippocampi with fewer neurons and performed worse in a cache recovery task and in a spatial version of an associative learning task. In contrast, performance of nutritionally deprived birds was similar to that of controls in 2 color versions of an associative learning task. These findings suggest that nutritional deficits during early development have long-term consequences for hippocampal structure and spatial memory, which, in turn, are likely to have a strong impact on animals' future fitness.

  4. Fused primary first mandibular macromolar with a unique relation to its permanent successors: A rare tooth anomaly.

    Science.gov (United States)

    Dhindsa, Abhishek; Garg, Shalini; Damle, S G; Opal, Shireen; Singh, Tavleen

    2013-04-01

    Dental anomalies of number and forms may occur in the primary and permanent dentition. Various terms have been used to describe dental twinning anomalies: Germination, fusion, concrescence, double teeth, conjoined teeth, twinned teeth, geminifusion, and vicinifusion. Fused tooth is a developmental anomaly that is seen more frequently in the primary than the permanent dentition. Double tooth involving deciduous anterior teeth is found mostly in the mandible. Very few cases of nonsyndromic double primary molar have been reported in the literature. The succeeding permanent tooth is often found missing congenitally in the same region. This article reports a very rare unilateral occurrence of an anomalous, primary mandibular first macromolar formed by fusion with a dysmorphic premolar like supernumerary tooth in deciduous dentition period. Instead of agenesis of succedaneous tooth, the double tooth has been succeeded by normally developing mandibular first premolar in the same region.

  5. Diagnostics of power transmissions system with tooth gear

    Directory of Open Access Journals (Sweden)

    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.

  6. Apical Revascularization after Delayed Tooth Replantation: An Unusual Case

    Directory of Open Access Journals (Sweden)

    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.

  7. Changes in gravitational force affect gene expression in developing organ systems at different developmental times

    Directory of Open Access Journals (Sweden)

    Moorman Stephen J

    2005-05-01

    Full Text Available Abstract Background Little is known about the affect of microgravity on gene expression, particularly in vivo during embryonic development. Using transgenic zebrafish that express the gfp gene under the influence of a β-actin promoter, we examined the affect of simulated-microgravity on GFP expression in the heart, notochord, eye, somites, and rohon beard neurons. We exposed transgenic zebrafish to simulated-microgravity for different durations at a variety of developmental times in an attempt to determine periods of susceptibility for the different developing organ systems. Results The developing heart had a period of maximum susceptibility between 32 and 56 hours after fertilization when there was an approximately 30% increase in gene expression. The notochord, eye, somites, and rohon beard neurons all showed periods of susceptibility occurring between 24 and 72 hours after fertilization. In addition, the notochord showed a second period of susceptibility between 8 and 32 hours after fertilization. Interestingly, all organs appeared to be recovering by 80 hours after fertilization despite continued exposure to simulated-microgravity. Conclusion These results support the idea that exposure to microgravity can cause changes in gene expression in a variety of developing organ systems in live embryos and that there are periods of maximum susceptibility to the effects.

  8. Changes in gravitational force affect gene expression in developing organ systems at different developmental times.

    Science.gov (United States)

    Shimada, Naoko; Sokunbi, Gbolabo; Moorman, Stephen J

    2005-05-31

    Little is known about the affect of microgravity on gene expression, particularly in vivo during embryonic development. Using transgenic zebrafish that express the gfp gene under the influence of a beta-actin promoter, we examined the affect of simulated-microgravity on GFP expression in the heart, notochord, eye, somites, and rohon beard neurons. We exposed transgenic zebrafish to simulated-microgravity for different durations at a variety of developmental times in an attempt to determine periods of susceptibility for the different developing organ systems. The developing heart had a period of maximum susceptibility between 32 and 56 hours after fertilization when there was an approximately 30% increase in gene expression. The notochord, eye, somites, and rohon beard neurons all showed periods of susceptibility occurring between 24 and 72 hours after fertilization. In addition, the notochord showed a second period of susceptibility between 8 and 32 hours after fertilization. Interestingly, all organs appeared to be recovering by 80 hours after fertilization despite continued exposure to simulated-microgravity. These results support the idea that exposure to microgravity can cause changes in gene expression in a variety of developing organ systems in live embryos and that there are periods of maximum susceptibility to the effects.

  9. Developing Automatic Form and Design System Using Integrated Grey Relational Analysis and Affective Engineering

    Directory of Open Access Journals (Sweden)

    Chen-Yuan Liu

    2018-01-01

    Full Text Available In the modern highly competitive marketplace and global market environment, product quality improvements that abridge development time and reduce the production costs are effective methods for promoting the business competitiveness of a product in shorter lifecycles. Since the design process is the best time to control such parameters, systematically designing the processes to develop a product that more closely fits the demand requirements for the market is a key factor for developing a successful product. In this paper, a combined affective engineering method and grey relational analysis are used to develop a product design process. First, design image scale technology is used to acquire the best the design criteria factors, and then affective engineering methods are used to set the relationships between customer needs and production factors. Finally, grey relational analysis is used to select the optimal design strategy. Using this systematic design method, a higher quality product can be expanded upon in a shorter lead-time for improving business competition.

  10. Exogenous growth factors do not affect the development of individually cultured murine embryos.

    Science.gov (United States)

    Herrick, Jason R; Greene-Ermisch, Alison F; Schoolcraft, William B; Krisher, Rebecca L

    2017-12-21

    The objective of this study was to evaluate the effects of multiple growth factors on the development of individually cultured murine embryos. Embryos produced by in vitro fertilization using in vitro (IVM) or in vivo (IVO) matured oocytes from three strains of mice (CF1, Swiss Webster, B6D2F1) were cultured individually (10 μl) in the absence (control) or presence of growth factors (paf, epidermal growth factor [EGF], insulin-like growth factor 1 [IGF-1], and granulocyte-macrophage colony-stimulating factor [GM-CSF]). Blastocyst formation, hatching, and blastocyst cell numbers (trophectoderm, inner cell mass, and total) were evaluated on days 4 and 5 of culture. Post-hatching development of CF1 IVO embryos was also evaluated in vitro and in vivo. The presence of growth factors did not improve the proportion of embryos forming blastocysts or initiating hatching for any of the types of embryos tested. The only significant (P embryos that formed blastocysts by day 5 in CF1 IVM embryos. The presence of growth factors also did not affect blastocyst cell numbers. For CF1 IVO embryos, the presence of growth factors during culture did not affect the proportion of embryos that attached to fibronectin-coated dishes, the size of the resulting outgrowths, or in vivo development following transfer. Combinations of paf, EGF, GM-CSF, and IGF-1 did not improve development of murine embryos cultured individually in a sequential medium containing a defined protein source.

  11. Effects of perinatal stress and drug abuse on maternal behavior and sensorimotor development of affected progeny.

    Science.gov (United States)

    Holubová, A; Ševčíková, M; Macúchová, E; Hrebíčková, I; Pometlová, M; Šlamberová, R

    2017-12-30

    Methamphetamine (MA) is an addictive psychostimulant with significant potential for abuse. Previous rat studies have demonstrated that MA use during pregnancy impairs maternal behavior and induced delayed development of affected pups. The offspring of drug-addictive mothers were often neglected and exposed to neonatal stressors. The present study therefore examines the effect of perinatal stressors combined with exposure to prenatal MA on the development of pups and maternal behavior. Dams were divided into three groups according to drug treatment during pregnancy: controls (C); saline (SA, s.c., 1 ml/kg); MA (s.c., 5 mg/ml/kg). Litters were divided into four groups according to postnatal stressors: controls (N); maternal separation (S); maternal cold-water stress (W); maternal separation plus cold-water stress (SW). The pup-retrieval test showed differences among postnatally stressed mothers and non-stressed controls. The righting reflex on a surface revealed delayed development of pups prenatally exposed to MA/SA and postnatal stress. Negative geotaxis and Rotarod results confirmed that the MA group was the most affected. Overall, our data suggests that a combination of perinatal stress and prenatal MA can have a detrimental effect on maternal behavior as well as on the sensorimotor development of pups. However, MA exposure during pregnancy seems to be the decisive factor for impairment.

  12. Psychosocial Aspect of Anterior Tooth Discoloration among ...

    African Journals Online (AJOL)

    Sixty two (65.9%), 47 (50.0%) and 38 (40.4%) respectively reported that it prevented them from freely answering questions, smiling and interacting. After oral examination, 120 (31.2%) subjects had one form of anterior tooth discoloration. The cause of tooth discoloration in the majority 64 (16.7%) of the participants was due ...

  13. psychosocial aspect of anterior tooth discoloration among

    African Journals Online (AJOL)

    discoloration on the psychosocial well being of adolescents with a view to providing information that will aid the ... Keywords: Psychosocial, Anterior tooth discolouration, Adolescents. Ann Ibd. Pg. Med 2011. Vol.9, No.2 94-99 ... often results in loss of self-esteem and damage to physical and mental health.9,10 Tooth ...

  14. Life of a Tooth: A Visual Timeline

    Medline Plus

    Full Text Available ... Posture! Is My Child at Risk for Early Childhood Tooth Decay? Men: Looking for a Better Job? Start by Visiting the Dentist Learn what those dental words mean. The Life of a Tooth Home | InfoBites | Find a Dentist | Your Family's Oral Health | RSS About AGD | Contact AGD | Site Map | Reprints ...

  15. 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…

  16. Single Visit Apexification Procedure of a Traumatically Injured Tooth with a Novel Bioinductive Material (Biodentine)

    Science.gov (United States)

    Jingarwar, Mahesh Madhukar; Pathak, Anuradha

    2015-01-01

    ABSTRACT Aim of this article is to present a case wherein single visit apexification of a traumatically injured tooth was done with a bioactive material–Biodentine. An injury sustained between the ages of 6 and 14 can adversely affect pulpal health and interrupt root development. In these instances, apexification is generally the preferred treatment. A 10 years old male patient presented with coronal fracture of the left upper central incisor. Clinical and radiographic assessment showed negative pulpal sensibility and arrested apical root development. Artificial apical barrier induction with Biodentine followed by endodontic treatment and prosthetic rehabilitation was decided as the line of treatment. To conclude, this bioactive and biocompatible calcium-based cement can regenerate damaged dental tissues and represents a promising alternative to the conventional multivisit apexification technique. Clinical significance: Biodentine which is a biologically active cement can be an efficient alternative to the conventional apexification materials which were hitherto recommended. How to cite this article: Bajwa NK, Jingarwar MM, Pathak A. Single Visit Apexification Procedure of a Traumatically Injured Tooth with a Novel Bioinductive Material (Biodentine). Int J Clin Pediatr Dent 2015;8(1):58-61. PMID:26124583

  17. Microleakage in different primary tooth restorations.

    Science.gov (United States)

    Shih, Wen-Yu

    2016-04-01

    Microleakage may cause tooth sensitivity, secondary caries, discoloration and even failure of the restoration. In order to overcome these potential problems, materials that are able to bind to the tooth structure have been developed, such as composite resin and glass ionomer cement. The purpose of the study was to compare microleakage arising from amalgam (Am), composite resin (CR), glass ionomer (GI), Ketac-Silver (KS), and GI filling with banding (GI+B) when these materials are used for class II restoration of a primary molar. Fifty primary molars were collected and class II cavities were prepared on each tooth. The teeth were randomly divided into five groups (Am, CR, GI, KS, and GI+B), each of which received a different material as part of the restoration. The restored teeth then underwent 100 cycles of thermocycling that consisted of 55°C for 30 seconds, 19°C for 20 seconds, and 5°C for 30 seconds. The teeth were then immersed in 0.5% basic fuchsin solution for 24 hours. Afterwards, the teeth were embedded and sectioned mesiodistally through the center of each restoration. Dye penetration associated with the occlusal and cervical margins of each restoration was then assessed. Cervical leakage was greater than occlusal leakage in the CR, GI and KS groups (p < 0.05). When leakage on occlusal margin was examined, however, the Am group showed greater leakage than the CR, GI, and GI+B groups (p < 0.05). When leakage on the cervical margin was examined, the Am group showed greater leakage than the GI and GI+B groups, while the KS group showed greater leakage than the GI+B group (p < 0.05). Restorations using GI and GI+B indicated that these materials performed better than the other materials in this study overall. However, none of the materials were entirely devoid of leakage. Copyright © 2016. Published by Elsevier Taiwan LLC.

  18. Integrative Review of Factors That Affect the Use of Postpartum Care Services in Developing Countries.

    Science.gov (United States)

    Adams, Yenupini Joyce; Smith, Barbara

    2018-03-07

    To identify factors that affect the use of postpartum care services in developing countries. PubMed, CINAHL, Global Health, EMBASE, and grey literature were searched for relevant articles in 2015 and 2016 with no publication date limit imposed. Thirteen studies met inclusion criteria and were assessed for quality with the use of a checklist developed by Fowkes and Fulton (1991) and a checklist developed by the Critical Appraisal Skills Programme (2017). The integrative review framework of Whittemore and Knafl (2005) guided the conduct of the review. Results were synthesized based on the three delays model of Thaddeus and Maine (1994). Factors that negatively affected women's decisions to seek postpartum care (Phase I delays) included lack of women's autonomy, lack of exposure to mass media, no pregnancy/birth/postpartum complications, lack of awareness of postpartum care, negative provider attitude, lower levels of women's and husbands' education, women's and husbands' farming occupations, increasing number of children, and lower level of household income. Perceived easy access to a health care facility was associated with lesser odds of using postpartum care (Phase II delay). Hospitals, public health care facilities, and long queuing at a health care facility were associated with decreased postpartum care use (Phase III delays). The most common determinants of how women used postpartum care were complications and the education levels and occupations of the women and their husbands. Further research is needed to identify health facility and accessibility factors that affect postpartum care use to develop effective interventions to improve the use of postpartum care. Copyright © 2018 AWHONN, the Association of Women’s Health, Obstetric and Neonatal Nurses. Published by Elsevier Inc. All rights reserved.

  19. Beeswax as dental filling on a neolithic human tooth.

    Directory of Open Access Journals (Sweden)

    Federico Bernardini

    Full Text Available Evidence of prehistoric dentistry has been limited to a few cases, the most ancient dating back to the Neolithic. Here we report a 6500-year-old human mandible from Slovenia whose left canine crown bears the traces of a filling with beeswax. The use of different analytical techniques, including synchrotron radiation computed micro-tomography (micro-CT, Accelerator Mass Spectrometry (AMS radiocarbon dating, Infrared (IR Spectroscopy and Scanning Electron Microscopy (SEM, has shown that the exposed area of dentine resulting from occlusal wear and the upper part of a vertical crack affecting enamel and dentin tissues were filled with beeswax shortly before or after the individual's death. If the filling was done when the person was still alive, the intervention was likely aimed to relieve tooth sensitivity derived from either exposed dentine and/or the pain resulting from chewing on a cracked tooth: this would provide the earliest known direct evidence of therapeutic-palliative dental filling.

  20. Beeswax as dental filling on a neolithic human tooth.

    Science.gov (United States)

    Bernardini, Federico; Tuniz, Claudio; Coppa, Alfredo; Mancini, Lucia; Dreossi, Diego; Eichert, Diane; Turco, Gianluca; Biasotto, Matteo; Terrasi, Filippo; De Cesare, Nicola; Hua, Quan; Levchenko, Vladimir

    2012-01-01

    Evidence of prehistoric dentistry has been limited to a few cases, the most ancient dating back to the Neolithic. Here we report a 6500-year-old human mandible from Slovenia whose left canine crown bears the traces of a filling with beeswax. The use of different analytical techniques, including synchrotron radiation computed micro-tomography (micro-CT), Accelerator Mass Spectrometry (AMS) radiocarbon dating, Infrared (IR) Spectroscopy and Scanning Electron Microscopy (SEM), has shown that the exposed area of dentine resulting from occlusal wear and the upper part of a vertical crack affecting enamel and dentin tissues were filled with beeswax shortly before or after the individual's death. If the filling was done when the person was still alive, the intervention was likely aimed to relieve tooth sensitivity derived from either exposed dentine and/or the pain resulting from chewing on a cracked tooth: this would provide the earliest known direct evidence of therapeutic-palliative dental filling.

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

    Science.gov (United States)

    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.

  2. Characteristics of activities that affect the development of women's same-sex relationships.

    Science.gov (United States)

    Davis-Delano, Laurel R

    2014-01-01

    The author utilized semistructured interviews with 56 women to explore how a wide range of activities affected the development of the participants' same-sex attractions and relationships. The researcher was able to identify and describe some aspects of the process by which eight characteristics of activities that are more or less present in various social contexts have the potential to impact whether these contexts are more or less conducive or hindering to the development of women's same-sex attractions and relationships. Activities were more apt to nurture the development of the participants' same-sex attractions and relationships when the activity (a) included lesbians, (b) was composed primarily of women, (c) affirmed women, (d) facilitated bonding, (e) featured a climate of acceptance of lesbians/gays/bisexuals, (f) did not feature a climate that emphasized heteronormativity, (g) was perceived as gender neutral, and (h) generated or drew participants who were similar to each other.

  3. Decision analysis and risk models for land development affecting infrastructure systems.

    Science.gov (United States)

    Thekdi, Shital A; Lambert, James H

    2012-07-01

    Coordination and layering of models to identify risks in complex systems such as large-scale infrastructure of energy, water, and transportation is of current interest across application domains. Such infrastructures are increasingly vulnerable to adjacent commercial and residential land development. Land development can compromise the performance of essential infrastructure systems and increase the costs of maintaining or increasing performance. A risk-informed approach to this topic would be useful to avoid surprise, regret, and the need for costly remedies. This article develops a layering and coordination of models for risk management of land development affecting infrastructure systems. The layers are: system identification, expert elicitation, predictive modeling, comparison of investment alternatives, and implications of current decisions for future options. The modeling layers share a focus on observable factors that most contribute to volatility of land development and land use. The relevant data and expert evidence include current and forecasted growth in population and employment, conservation and preservation rules, land topography and geometries, real estate assessments, market and economic conditions, and other factors. The approach integrates to a decision framework of strategic considerations based on assessing risk, cost, and opportunity in order to prioritize needs and potential remedies that mitigate impacts of land development to the infrastructure systems. The approach is demonstrated for a 5,700-mile multimodal transportation system adjacent to 60,000 tracts of potential land development. © 2011 Society for Risk Analysis.

  4. Recommendations to enable drug development for inherited neuropathies: Charcot-Marie-Tooth and Giant Axonal Neuropathy [v2; ref status: indexed, http://f1000r.es/3am

    Directory of Open Access Journals (Sweden)

    Lori Sames

    2014-04-01

    Full Text Available Approximately 1 in 2500 Americans suffer from Charcot-Marie-Tooth (CMT disease. The underlying disease mechanisms are unique in most forms of CMT, with many point mutations on various genes causing a toxic accumulation of misfolded proteins. Symptoms of the disease often present within the first two decades of life, with CMT1A patients having reduced compound muscle and sensory action potentials, slow nerve conduction velocities, sensory loss, progressive distal weakness, foot and hand deformities, decreased reflexes, bilateral foot drop and about 5% become wheelchair bound. In contrast, the ultra-rare disease Giant Axonal Neuropathy (GAN is frequently described as a recessively inherited condition that results in progressive nerve death. GAN usually appears in early childhood and progresses slowly as neuronal injury becomes more severe and leads to death in the second or third decade. There are currently no treatments for any of the forms of CMTs or GAN. We suggest that further clinical studies should analyse electrical impedance myography as an outcome measure for CMT. Further, additional quality of life (QoL assessments for these CMTs are required, and we need to identify GAN biomarkers as well as develop new genetic testing panels for both diseases. We propose that using the Global Registry of Inherited Neuropathy (GRIN could be useful for many of these studies. Patient advocacy groups and professional organizations (such as the Hereditary Neuropathy Foundation (HNF, Hannah's Hope Fund (HHF, The Neuropathy Association (TNA and the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM can play a central role in educating clinicians and patients. Undertaking these studies will assist in the correct diagnosis of disease recruiting patients for clinical studies, and will ultimately improve the endpoints for clinical trials. By addressing obstacles that prevent industry investment in various forms of inherited neuropathies

  5. 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.

  6. Nine Novel PAX9 Mutations and a Distinct Tooth Agenesis Genotype-Phenotype.

    Science.gov (United States)

    Wong, S-W; Han, D; Zhang, H; Liu, Y; Zhang, X; Miao, M Z; Wang, Y; Zhao, N; Zeng, L; Bai, B; Wang, Y-X; Liu, H; Frazier-Bowers, S A; Feng, H

    2018-02-01

    Tooth agenesis is one of the most common developmental anomalies affecting function and esthetics. The paired-domain transcription factor, Pax9, is critical for patterning and morphogenesis of tooth and taste buds. Mutations of PAX9 have been identified in patients with tooth agenesis. Despite significant progress in the genetics of tooth agenesis, many gaps in knowledge exist in refining the genotype-phenotype correlation between PAX9 and tooth agenesis. In the present study, we complete genetic and phenotypic characterization of multiplex Chinese families with nonsyndromic (NS) tooth agenesis. Direct sequencing of polymerase chain reaction products revealed 9 novel (c.140G>C, c.167T>A, c.332G>C, c.194C>A, c.271A>T, c.146delC, c.185_189dup, c.256_262dup, and c.592delG) and 2 known heterozygous mutations in the PAX9 gene among 120 probands. Subsequently, pedigrees were extended, and we confirmed that the mutations co-segregated with the tooth agenesis phenotype (with exception of families in which DNA analysis was not available). In 1 family ( n = 6), 2 individuals harbored both the PAX9 c.592delG mutation and a heterozygous missense mutation (c.739C>T) in the MSX1 gene. Clinical characterization of families segregating a PAX9 mutation reveal that all affected individuals were missing the mandibular second molar and their maxillary central incisors are most susceptible to microdontia. A significant reduction of bitter taste perception was documented in individuals harboring PAX9 mutations ( n = 3). Functional studies revealed that PAX9 haploinsufficiency or a loss of function of the PAX9 protein underlies tooth agenesis.

  7. Effects of Evaluator's Fatigue and Level of Expertise on the Global and Analytical Evaluation of Preclinical Tooth Preparation.

    Science.gov (United States)

    Al Amri, Mohammad D; Sherfudhin, Haneef R; Habib, Syed R

    2016-11-03

    To investigate the effects of evaluator fatigue and level of expertise on the grading of preclinical tooth crown preparations, by global and analytical methods of evaluation. The study had a double-blind design. Two faculty members, each with more than 10 years of clinical and teaching experience, and two demonstrators with no teaching experience evaluated tooth preparations on maxillary central incisors and mandibular first molars. As a test of the effect of fatigue, preparations were globally (subjective grading) and analytically (criteria-based grading) graded on day 1 (after evaluators had been on duty continuously for 8 hours) and day 2 (in the morning after evaluators had sufficient sleep). Evaluators worked under the same circumstances and did not communicate with each other. The assigned textbooks were used to develop the criteria for grading (rubric) and the predefined exclusion criteria. Grades were recorded and statistically analyzed using statistical software. The paired-sample t-test and Mann-Whitney U test were used for multiple comparisons. Level of significance was set at p ˂ 0.05. An inconsistency in preclinical tooth preparation evaluation was found to exist by both global and analytical methods. Junior faculty tended to award higher grades than senior faculty did. Furthermore, higher grades were scored by the analytical method. More clinical and academic experience did not guarantee intra- and interexaminer reliability. Younger faculty appeared to tolerate fatigue better than older faculty. Likewise, global evaluation appeared to be more influenced by fatigue than was the analytical method. There were variations in grading, with no consistently preferred grading method. Evaluator performance after continuous 8-hour duty had no significant effect on preclinical tooth preparation evaluation. Level of expertise did not affect preclinical evaluation regardless of the grading method used. © 2016 by the American College of Prosthodontists.

  8. DOFT and DOFTIP1 affect reproductive development in the orchid Dendrobium Chao Praya Smile.

    Science.gov (United States)

    Wang, Yanwen; Liu, Lu; Song, Shiyong; Li, Yan; Shen, Lisha; Yu, Hao

    2017-12-16

    FLOWERING LOCUS T (FT) in Arabidopsis encodes the florigen that moves from leaves to the shoot apical meristem to induce flowering, and this is partly mediated by FT-INTERACTING PROTEIN 1 (FTIP1). Although FT orthologs have been identified in some flowering plants, their endogenous roles in Orchidaceae, which is one of the largest families of flowering plants, are still largely unknown. In this study, we show that DOFT and DOFTIP1, the orchid orthologs of FT and FTIP1, respectively, play important roles in promoting flowering in the orchid Dendrobium Chao Praya Smile. Expression of DOFT and DOFTIP1 increases in whole plantlets during the transition from vegetative to reproductive development. Both transcripts are present in significant levels in reproductive organs, including inflorescence apices, stems, floral buds, and open flowers. Through successful generation of transgenic orchids, we have revealed that overexpression or down-regulation of DOFT accelerates or delays flowering, respectively, while alteration of DOFT expression also greatly affects pseudobulb formation and flower development. In common with their counterparts in Arabidopsis and rice, DOFTIP1 interacts with DOFT and affects flowering time in orchids. Our results suggest that while DOFT and DOFTIP1 play evolutionarily conserved roles in promoting flowering, DOFT may have evolved with hitherto unknown functions pertaining to the regulation of storage organs and flower development in the Orchidaceae family. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  9. Elevated temperature affects development, survivorship, and settlement of the elkhorn coral, Acropora palmata (Lamarck 1816).

    Science.gov (United States)

    Randall, Carly J; Szmant, Alina M

    2009-12-01

    Elevated seawater temperatures during the late summer have the potential to negatively affect the development and survivorship of the larvae of reef corals that are reproductive during that time of year. Acropora palmata, a major Caribbean hermatype, reproduces annually during August and September. A. palmata populations have severely declined over the past three decades, and recovery will require high recruitment rates. Such recruitment will be limited if larval supply is reduced by elevated temperatures. The effects of elevated temperatures on development, survival, and larval settlement of A. palmata were investigated by culturing newly fertilized eggs at temperatures ranging from 27.5 to 31.5 degrees C. Development was accelerated and the percentage of developmental abnormalities increased at higher temperatures. Embryo mortality peaked during gastrulation, indicating that this complex developmental process is particularly sensitive to elevated temperatures. Larvae cultured at 30 and 31.5 degrees C experienced as much as an 8-fold decrease in survivorship compared to those at 28 degrees C. Additionally, settlement was 62% at 28 degrees C compared to 37% at 31.5 degrees C. These results indicate that embryos and larvae of A. palmata will be negatively affected as sea surface temperatures continue to warm, likely reducing recruitment and the recovery potential of A. palmata on Caribbean reefs.

  10. Manipulation of postnatal testosterone levels affects phallic and clitoral development in infant rhesus monkeys.

    Science.gov (United States)

    Brown, G R; Nevison, C M; Fraser, H M; Dixson, A F

    1999-04-01

    Male primates exhibit marked elevation of circulating testosterone levels during the early postnatal period. The aim of this project was to test whether experimental manipulation of circulating testosterone levels in male and female infant rhesus monkeys affected development of the external genitalia during the first six months of life. Four groups of infants were studied. Seven control male infants exhibited high circulating testosterone levels during the first three months of life. Seven males were treated with a GnRH agonist (avorelin) from the first week of life onwards, which suppressed the postnatal testosterone surge. Ten control females exhibited low circulating testosterone levels during the early postnatal period. Administration of testosterone to 10 females resulted in high circulating levels in these infants. Fortnightly blood samples and genital measurements were taken from all infants during the first six months of life. Growth of the penis of avorelin-treated males was significantly retarded when compared to control males. Average length of the penis at six months of age was significantly (p = 0.012) smaller for avorelin-treated males (25.2 +/- 2.8 mm) than for control males (37.3 +/- 3.0 mm). Avorelin-treated males attained only around 50% detachment of the prepuce from the glans of the penis, while control males averaged 90% detachment. Treatment of females with testosterone resulted in significant growth of the clitoris in comparison to control females. The growth rates of the penis of control males and clitorides of testosterone-treated females were similar and greatest during the first two months of life. Gain in body weight was not affected by either hormonal manipulation. It is concluded that manipulation of circulating testosterone levels during the early postnatal period affects penile and clitoral development of infant rhesus monkeys. This postnatal period may therefore represent an important stage in penile development in primates.

  11. Neuromuscular Hip Dysplasia in Charcot-Marie-Tooth Disease Type 1A

    Science.gov (United States)

    Bamford, Nigel S.; White, Klane K.; Robinett, Stephanie A.; Otto, Randolph K.; Gospe, Sidney M., Jr.

    2009-01-01

    Charcot-Marie-Tooth disease (CMT) is one of the most common inherited neurological disorders, affecting 36 in 100,000 people. CMT type 1A (hereditary motor and sensory neuropathy) is the most frequent form of this disease, affecting 60 to 80% of the CMT population, but its diagnosis may be delayed because of inconsistent clinical signs and…

  12. Increased risk of developing stroke for patients with major affective disorder--a registry study

    DEFF Research Database (Denmark)

    Nilsson, Flemming M; Kessing, Lars V

    2004-01-01

    Only a few studies have evaluated depressive disorder as a risk factor for cerebrovascular disease. In a hospital discharge register with nation-wide coverage of all hospitals in Denmark we used linkage between the somatic and psychiatric registries to study comorbidity between affective disorders...... and cerebrovascular diseases in hospitalised patients. The main finding of this study was that patients with depression severe enough to be hospitalised, seem to be at an increased risk of developing cerebrovascular disease. The hazard ratio of getting a diagnosis of stroke after initially having been discharged...... and especially the risk of stroke should be considered....

  13. Development programmes in rural communities affected by industrial sites. The case of nuclear plants in Spain

    International Nuclear Information System (INIS)

    Yuncal, A.

    2000-01-01

    A socioeconomic analysis performed for rural communities affected by industrial sites, namely for the case of nuclear power plants in Spain a common proposal for all the European countries is made. Existence of a common European program that could cover the following aspects: Creation of a Committee to enhance the participation in decision making process on different aspects, information policies, security, transport, waste management, investments, economic development; Contract between local authorities, State and companies responsibilities and financing; Legal framework of political organization; common socio-economic program including environment, employment, companies activities, responsibilities, taxes

  14. 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

  15. Nickel affects gill and muscle development in oriental fire-bellied toad (Bombina orientalis) embryos

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chan Jin; Song, Sang Ha; Kim, Dae Han; Gye, Myung Chan, E-mail: mcgye@hanyang.ac.kr

    2017-01-15

    Highlights: • Nickel inhibited the development of external gill in B. orientalis embryos. • The 168 h LC{sub 50} and EC{sub 50} values of nickel were 33.8 and 5.4 μM, respectively, in embryos. • Nickel induced abnormal tail development of embryos. • NF stage 26–31 was the most sensitive window for embryos to nickel exposure. • Nickel affected the calcium-dependent myogenic gene expression in embryos. - Abstract: The developmental toxicity of nickel was examined in the embryos of Bombina orientalis, a common amphibian in Korea. Based on a standard frog embryo teratogenesis assay, the LC{sub 50} and EC{sub 50} for malformation of nickel after 168 h of treatment were 33.8 μM and 5.4 μM, respectively. At a lethal concentration (100 μM), nickel treatment decreased the space between gill filaments and caused epithelial swelling and abnormal fusion of gill filaments. These findings suggest that nickel affects the functional development of gills, leading to embryonic death. At sublethal concentrations (1–10 μM), nickel produced multiple embryonic abnormalities, including bent tail and tail dysplasia. At 10 μM, nickel significantly decreased tail length and tail muscle fiber density in tadpoles, indicating inhibition of myogenic differentiation. Before hatching, the pre-muscular response to muscular response stages (stages 26–31) were the most sensitive period to nickel with respect to tail muscle development. During these stages, MyoD mRNA was upregulated, whereas myogenic regulatory factor 4 mRNA was downregulated by 0.1 μM nickel. Calcium-dependent kinase activities in muscular response stage embryos were significantly decreased by nickel, whereas these activities were restored by exogenous calcium. In tadpoles, 10 μM nickel significantly decreased the expression of the myosin heavy chain and the 12/101 muscle marker protein in the tail. Expression was restored by exogenous calcium. Our results indicate that nickel affects muscle development by

  16. International trends affecting the development of small and medium sized reactors

    International Nuclear Information System (INIS)

    Echavarri, L.

    2002-01-01

    The beginning of the 21st century is characterised by significant changes in the energy policy-making framework of most countries. Globalisation of the world economy, deregulation of electricity markets, privatisation of the electricity sector, increasing concerns about the need to protect the environment and awareness of sustainable development goals are among the major trends affecting policy making and decisions in the energy sector. All those factors have impacts on nuclear energy programmes and may affect SMR development in particular. The paper investigates how those factors may change national energy policies and impact on nuclear energy programmes, with special emphasis on the potential role of SMRs in energy supply mixes. It elaborates on recent trends to increasing reliance on market mechanisms in the energy and electricity sectors and on the role of governments in implementing an integrated approach to policy making, within a sustainable development framework incorporating economic, social and environmental dimensions. Against this backdrop, the paper examines the potential markets for SMRs, taking into account their possible uses beyond electricity generation, such as potable water production, cogeneration, process or domestic heat supply and eventually hydrogen production. It reviews key issues to be addressed in order to facilitate the deployment of SMRs in different countries. Those include technology progress and transfer, capacity building in developing countries, adaptation to market requirements, economic competitiveness and social acceptance. The paper concludes with remarks regarding the importance of international co-operation, especially in the field of research and development on advanced reactor and fuel cycle concepts. In this connection, the role of intergovernmental organisations as facilitators and catalysts of national efforts is highlighted. (author)

  17. Mechanism of human tooth eruption

    DEFF Research Database (Denmark)

    Kjær, Inger

    2014-01-01

    Human eruption is a unique developmental process in the organism. The aetiology or the mechanism behind eruption has never been fully understood and the scientific literature in the field is extremely sparse. Human and animal tissues provide different possibilities for eruption analyses, briefly...... discussed in the introduction. Human studies, mainly clinical and radiological, have focused on normal eruption and gender differences. Why a tooth begins eruption and what enables it to move eruptively and later to end these eruptive movements is not known. Pathological eruption courses contribute......, and the ability of the periodontal ligament to adapt to eruptive movements. Animal studies and studies on normal and pathological eruption in humans can support and explain different aspects in the new theory. The eruption mechanism still needs elucidation and the paper recommends that future research on eruption...

  18. Photometric assessment of tooth color using commonly available software.

    Science.gov (United States)

    Denissen, Harry; Dozic, Alma

    2010-01-01

    It would be expedient to develop a simple digital procedure for matching shade guides to teeth for dental restorations. It was hypothesized that precise and objective L*a*b* measurements could be performed on photographic images of teeth and shade guides using commonly available photo software. Tooth shade guide tabs, shaped like computer-generated posterior crowns, were used for color matching. Digital photographs were obtained of the vestibular surface of the tooth and the neighboring shade guide. Sections of the tooth and shade guide on the photograph were cropped and analyzed in Photoshop CS2. The precision error of the measurements was expressed as the coefficient of variation in percent. The effects of tolerance setting and number of measurements and analysts were evaluated. The difference in color was calculated as the DeltaE L*a*b*. The precision errors of the L*a*b* measurements with a tolerance setting of 6 pixels were better than 1.3%. There was no significant difference between one and five repeated measurements or between the measurements and the precision errors of two analysts. Color differences (DeltaE) between repeated measurements were below 0.5 units, thus reproducible and visually identical. DeltaE L*a*b* calculations were expedient for matching a particular color guide tab to the neighboring tooth. The color coordinates L*a*b* of teeth and shade guides can be calculated with a precision error of only 1.3%, using readily available software. A tolerance setting of 6 pixels is optimal and only one measurement and one analyst are necessary for objective and precise measurements. The described digital L*a*b* measurements on a photograph offer the dentist and the ceramist a simple, precise, and objective tool for matching tooth and shade guide.

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

    Science.gov (United States)

    ... Finding Dental Care Home Health Info Health Topics Tooth Decay Tooth decay (dental caries) is damage to a tooth that can happen ... hole in a tooth, called a cavity. If tooth decay is not treated, it can cause pain, infection, ...

  20. Key Factors Affecting Construction Safety Performance in Developing Countries: Evidence from Cambodia

    Directory of Open Access Journals (Sweden)

    Serdar Durdyev

    2017-12-01

    Full Text Available Although proper safety management in construction is of utmost importance; anecdotal evidence suggests that safety is not adequately considered in many developing countries. This paper considers the key variables affecting construction safety performance in Cambodia. Using an empirical questionnaire survey targeting local construction professionals, respondents were invited to rate the level of importance of 30 variables identified from the seminal literature. The data set was subjected to factor analysis. Correlations between the variables show that five key factors underlie the challenges facing the local industry; management and organisation, resources, site management, cosmetic and workforce. It is found that the forefront construction professionals (top management and government authorities should take more responsibilities for further improvements in safety performance on project sites. Findings and recommendations of this study may be useful to construction professional who are seeking ways to improve safety records in developing countries.

  1. Polycyclic aromatic hydrocarbons affect survival and development of common snapping turtle (Chelydra serpentina) embryos and hatchlings

    International Nuclear Information System (INIS)

    Van Meter, Robin J.; Spotila, James R.; Avery, Harold W.

    2006-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are toxic compounds found in the John Heinz National Wildlife Refuge in Philadelphia, Pennsylvania. We assessed the impact of PAHs and crude oil on snapping turtle development and behavior by exposing snapping turtle eggs from the Refuge and from three clean reference sites to individual PAHs or a crude oil mixture at stage 9 of embryonic development. Exposure to PAHs had a significant effect on survival rates in embryos from one clean reference site, but not in embryos from the other sites. There was a positive linear relationship between level of exposure to PAHs and severity of deformities in embryos collected from two of the clean reference sites. Neither righting response nor upper temperature tolerance (critical thermal maximum, CTM) of snapping turtle hatchlings with no or minor deformities was significantly affected by exposure to PAHs. - Exposure to polycyclic aromatic hydrocarbons on the egg reduces survival of snapping turtle embryos and causes developmental abnormalities

  2. The relationship between tooth wear in the primary and permanent dentitions.

    Science.gov (United States)

    Sales-Peres, S H C; Sales-Peres, A C; Marsicano, J A; Carvalho, C A P; Carvalho, F S; Lauris, J R P; Sales-Peres, A

    2011-09-01

    To evaluate the relationship between tooth wear in primary and permanent dentition in 7 to 10-year-old school children, in 2007. An epidemiological cross-sectional survey was conducted by trained, calibrated examiners, using the dental wear index (DWI). The cluster sample consisted of 764 children (382 boys, 382 girls) attending 4 public schools selected in different regions of the city. The DWI was proposed to evaluate primary and permanent teeth, coded as letters and numbers, respectively. Data were collected via clinical examinations performed outdoors under natural light, following the WHO recommendations and using a dental mirror and probe. Proportions and confidence intervals were used to describe the prevalence of dental wear. The Mann-Whitney and the Odds Ratio (OR) tests were used to compare the tooth wear prevalence between primary and permanent teeth according to surface (p tooth wear. The tooth wear was mostly seen on the occlusal/incisal surfaces (47%), involving enamel or enamel-dentine. Tooth wear in primary teeth was found in canines and molars (93%) and in permanent teeth in molars (34%). There was significant difference between primary and permanent teeth (p primary teeth was greater in boys than in girls (p = 0.02) but not in permanent teeth. The results suggest that 7 to 10-year-old children with tooth wear in primary teeth had more chances of developing tooth wear in permanent dentition. However, the findings of this study are not conclusive as the associations described are not causal.

  3. Evaluation of autogenous tooth transplantation for replacement of the missing or unrestorable mandibular molar tooth

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    Wahiduj Jaman

    2017-06-01

    Full Text Available This study was undertaken to evaluate the functional and occlusal stability of autogenous tooth transplantation. A total of 30 patients were included. Among them, 21 participants received transplanted first molar and the remaining 9 received transplanted second molar. In all the cases, donor tooth were third molar. In each participant, extraction of un-restorable first or second molar tooth was performed which was then replaced by atrumatic extracted third molar tooth. Each third molar tooth was placed in the recipient extracted socket, followed by the evaluation of the occlusion and then stabilized with arch bar and ligature wire. Clinical follow-up evaluation was performed at 15 days, 3 and 12 months in respect to occlusal stability, tooth mobility and periodontal status. It was found that 23 transplanted tooth were successful and the remaining 7 tooth need long-term observation for the final outcome, which was statistically significant. It can be concluded that the autogenous tooth transplantation can replace missing tooth to ensure the preservation of function, aesthetic and to prevent bone resorption of the missing area of the jaw, which can lead to exceptional esthetic and functional outcome.

  4. Development of the internet based psychoeducation for patients with bipolar affective disorder.

    Science.gov (United States)

    Prasko, Jan; Kamaradova, Dana; Jelenova, Daniela; Ociskova, Marie; Sedlackova, Zuzana

    2013-01-01

    Despite pharmacological treatment of bipolar affective disorder has many advantages; only drug treatment remains insufficiently beneficial to many patients. The combination of pharmacotherapy and internet psychoeducation seems to be the effective way how to improve remission. Internet-based therapy programs offer an exclusive chance for large underserved parts of the population to make evidence-based treatment without the need of full-time therapist. Our goal was to create a psychoeducational program for patients suffering from bipolar disorder that can be used in Czech Republic. There were identified studies through Web of Science, PUBMED, and Scopus databases as well as existing reviews were used in development of comprehensive internet psychoeducational program for patients with bipolar disorder. The search terms included "bipolar disorder", "psychoeducation", and "internet psychoeducation". The search was performed with no language or time restrictions. The internet psychoeducational program was developed in accordance to the data from the literature review. The aim of the Internet psychoeducational program of the Department of Psychiatry University Hospital in Olomouc is to familiarize patients with the fundamental nature of bipolar affective disorder, the character and principles of pharmacotherapy, the recognition of the warning signs of relapse, inappropriate and stressful stereotypes in communication within families, and finally the practice of social skills. Information from studies can help to prepare comprehensive psychoeducational program for bipolar patients.

  5. Governance Factors Affecting Community Participation In Public Development Projects In Meru District In Arusha In Tanzania

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    Jackson Estomih Muro

    2015-06-01

    Full Text Available ABSTRACT The purpose of this study was to have a fresh look at the local governance status through exploring governance factors affecting community participation in public development projects. The study also has investigated the actors and factors shaping participation as well as causes for non-participation. For the purpose of the study six wards within two divisions of Poli and Mbuguni and Meru district headquarters were selected. In the wards a total of 80 respondents from among the community members were interviewed through a structured questionnaire. Others were Village chairman Village Executive Officers Ward Executive Officers and Councilors were also interviewed and involved in the FGD. Data were analyzed using SPSS. Simple descriptive statistics and cross tabulation and figures were used in the analysis. The analysis showed that the communities were participated in the public development projects and people were participating through financial material and labor contribution to the public development projects. The analysis also showed that the government supported the ongoing public development projects including through provision of fund and expertise. The study showed the benefit of community participation in the development projects or programs like ownership of the projects and enjoying the benefits accrued from the projects. The study also indicated that there is significant change in terms of governance as influencers of community participation in public development projects. Despite the fortunes study showed some challenges found in wards and villages being the incidence of corruptions and misuse of public resources which were mentioned to slow community participation in public development projects. It was therefore concluded that adhering to the good governance principles contribute positively towards community participation in public development projects.

  6. The cracked tooth: histopathologic and histobacteriologic aspects.

    Science.gov (United States)

    Ricucci, Domenico; Siqueira, José F; Loghin, Simona; Berman, Louis H

    2015-03-01

    The diagnosis and treatment planning of cracked teeth depend on the understanding of how cracks affect the surrounding tissues. This study evaluated the dentin and pulp conditions in teeth affected by cracks and attrition. Specimens under investigation included 12 cracked posterior teeth and 8 teeth with severe attrition. These teeth were obtained consecutively in a private practice and were extracted for reasons not related to this study. Teeth were processed for histopathologic and histobacteriologic analyses. Cracks were histologically detected in all specimens, including the teeth with severe attrition. The cracks in all teeth were colonized by bacterial biofilms. One tooth showed several craze lines in the enamel, one of which reached dentin to a shallow depth. In some teeth, the crack ended in the dentin. Dentinal tubules were invaded by bacteria, especially when the crack extended perpendicularly into the dentin. Severe accumulations of inflammatory cells were present in the pulp zone subjacent to tubules involved with the crack. In many cases, the crack extended to the pulp, leading to reactions with intensities ranging from acute inflammation to total pulpal necrosis. Symptoms occurred in most cases in which the pulp was affected. In some cases, polymorphonuclear neutrophils were seen migrating from the pulp into the crack space and facing the bacterial biofilm located therein. Severe pulp reactions were also observed when the crack extended to the pulp chamber floor. Cracks are always colonized with bacterial biofilms. The pulp tissue response varies according to the location, direction, and extent of the crack. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  7. Prevalence and genetic basis of tooth agenesis

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    Takehiko Shimizu

    2009-05-01

    Full Text Available Tooth agenesis or hypodontia is one of the most common anomalies of the human dentition, characterized by the developmental absence of one or more teeth. Many studies have reported that the prevalence of congenital absence of permanent teeth varies from 3% to 11% among European and Asian populations. Recent advances in the fields of molecular biology and human genetics have improved our understanding of the cause of tooth agenesis. In this review, we assess the previous literature on prevalence of tooth agenesis comparing the Japanese with other racial populations, and describe the recent genetic studies associated with hypodontia in human and mouse models.

  8. 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).

  9. Properties of tooth enamel in great apes.

    Science.gov (United States)

    Lee, James J-W; Morris, Dylan; Constantino, Paul J; Lucas, Peter W; Smith, Tanya M; Lawn, Brian R

    2010-12-01

    A comparative study has been made of human and great ape molar tooth enamel. Nanoindentation techniques are used to map profiles of elastic modulus and hardness across sections from the enamel-dentin junction to the outer tooth surface. The measured data profiles overlap between species, suggesting a degree of commonality in material properties. Using established deformation and fracture relations, critical loads to produce function-threatening damage in the enamel of each species are calculated for characteristic tooth sizes and enamel thicknesses. The results suggest that differences in load-bearing capacity of molar teeth in primates are less a function of underlying material properties than of morphology. Published by Elsevier Ltd.

  10. The association between childhood obesity and tooth eruption.

    Science.gov (United States)

    Must, Aviva; Phillips, Sarah M; Tybor, David J; Lividini, Keith; Hayes, Catherine

    2012-10-01

    Obesity is a growth-promoting process as evidenced by its effect on the timing of puberty. Although studies are limited, obesity has been shown to affect the timing of tooth eruption. Both the timing and sequence of tooth eruption are important to overall oral health. The purpose of this study was to examine the association between obesity and tooth eruption. Data were combined from three consecutive cycles (2001-2006) of the National Health and Nutrition Examination Survey (NHANES) and analyzed to examine associations between the number of teeth erupted (NET) and obesity status (BMI z-score >95th percentile BMI relative to the Centers for Disease Control and Prevention (CDC) growth reference) among children 5 up to 14 years of age, controlling for potential confounding by age, gender, race, and socioeconomic status (SES). Obesity is significantly associated with having a higher average NET during the mixed dentition period. On average, teeth of obese children erupted earlier than nonobese children with obese children having on average 1.44 more teeth erupted than nonobese children, after adjusting for age, gender, and race/ethnicity (P erupted than nonobese children after adjusting for gender, age, and race. These findings may have clinical importance in the area of dental and orthodontic medicine both in terms of risk for dental caries due to extended length of time exposed in the oral cavity and sequencing which may increase the likelihood of malocclusions.

  11. Factors Affecting Resilience and Development of Posttraumatic Stress Disorder in Critical Care Nurses.

    Science.gov (United States)

    Mealer, Meredith; Jones, Jacqueline; Meek, Paula

    2017-05-01

    Job stress and cumulative exposure to traumatic events experienced by critical care nurses can lead to psychological distress and the development of burnout syndrome and posttraumatic stress disorder. Resilience can mitigate symptoms associated with these conditions. To identify factors that affect resilience and to determine if the factors have direct or indirect effects on resilience in development of posttraumatic stress disorder. Data from 744 respondents to a survey mailed to 3500 critical care nurses who were members of the American Association of Critical-Care Nurses were analyzed. Mplus was used to analyze a mediation model. Nurses who worked in any type of intensive care unit other than the medical unit and had high scores for resilience were 18% to 50% less likely to experience post-traumatic stress disorder than were nurses with low scores. Nurses with a graduate degree in nursing were 18% more likely to experience posttraumatic stress disorder than were nurses with a bachelor's degree. Because of their effects on resilience, working in a medical intensive care unit and having a graduate degree may influence the development of posttraumatic stress disorder. Future research is needed to better understand the impact of resilience on health care organizations, development of preventive therapies and treatment of posttraumatic stress disorder for critical care nurses, and the most appropriate mechanism to disseminate and implement strategies to address posttraumatic stress disorder. ©2017 American Association of Critical-Care Nurses.

  12. Factors affecting the impact of professional development programs on teachers' knowledge, practice, student outcomes & efficacy.

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    Lawrence Ingvarson

    2005-01-01

    Full Text Available This report examines effects of structural and process features of professional development programs on teachers' knowledge, practice and efficacy. It is based on four recent (2002-2003 studies undertaken through the Australian Government Quality Teacher Programme, designed to enhance teacher quality. The total data set for the survey study includes 3,250 teachers who had participated in eighty individual professional development1 activities within these studies. Teachers were surveyed at least three months after participating in an activity, which provided them with the opportunity to gauge the impact of programs on their practice. To investigate factors affecting impact, a theoretical model was developed based on recent research into the characteristics of effective professional development and tested using blockwise regression analysis. The model included contextual factors (e.g., school support, structural features of programs (e.g. ,length, process features (e.g., emphasis on content; active learning; examination of student work; feedback; follow-up, a mediating variable (level of professional community generated, and four outcome measures (knowledge; practice; student learning and efficacy. Consistent significant direct effects were found across the four studies for the impact of content focus, active learning, and follow-up on knowledge and professional community. Feedback was rarely incorporated into program design. Impact on efficacy was strongly related to the perceived impact of activities on teachers' practice and student learning outcomes.

  13. The Development of Assistive Systems to Support Older People: Issues that Affect Success in Practice

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    Jean D. Hallewell Haslwanter

    2017-12-01

    Full Text Available Due to an aging population in Europe, the development of Ambient Assisted Living technologies (AAL is increasingly the target of research financing. These technologies promise to enable older people to remain in their own homes longer, something many people report wanting and which may also reduce the costs of care. To date however there are few systems on the market. Other studies have tried to understand this by looking at user acceptance. However, by looking only at the user acceptance, we may miss important aspects to explain why systems went wrong in the first place, since decisions made during the development may affect the success later. To address this, we report on a study in which we applied qualitative methods, including workshops and an interactive poster, to consult with people who have experience in the development of these technologies. We present the common issues reported across various AAL development projects done in Europe that the participants thought were important to the success or failure of projects. We also describe some ideas from participants for addressing some of these problems. The results demonstrate the importance of issues related to financing with grants for projects but also the need for improved user-centered practice.

  14. The histone acetyltransferase GCN5 affects the inflorescence meristem and stamen development in Arabidopsis.

    Science.gov (United States)

    Cohen, Ross; Schocken, John; Kaldis, Athanasios; Vlachonasios, Konstantinos E; Hark, Amy T; McCain, Elizabeth R

    2009-11-01

    A central question in biology is to understand how gene expression is precisely regulated to give rise to a variety of forms during the process of development. Epigenetic effects such as DNA methylation or histone modification have been increasingly shown to play a critical role in regulation of genome function. GCN5 is a prototypical histone acetyltransferase that participates in regulating developmental gene expression in several metazoan species. In Arabidopsis thaliana, plants with T-DNA insertions in GCN5 (also known as HAG1) display a variety of pleiotropic effects including dwarfism, loss of apical dominance, and floral defects affecting fertility. We sought to determine when during early development floral abnormalities first arise. Using scanning electron microscopy, we demonstrate that gcn5-1/hag1-1 and gcn5-5/hag1-5 mutants display overproliferation of young buds and development of abnormal structures around the inflorescence meristem. gcn5 mutants also display defects in stamen number and arrangement at later stages. This analysis provides temporal and spatial information to aid in the identification of GCN5 target genes in the developing flower. Preliminary studies of putative targets using reverse transcriptase PCR suggest that the floral meristem identity gene LEAFY is among factors upregulated in gcn5-1 mutants.

  15. Development of Upper Respiratory Tract Microbiota in Infancy is Affected by Mode of Delivery

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    Astrid A.T.M. Bosch

    2016-07-01

    Full Text Available Birth by Caesarian section is associated with short- and long-term respiratory morbidity. We hypothesized that mode of delivery affects the development of the respiratory microbiota, thereby altering its capacity to provide colonization resistance and consecutive pathobiont overgrowth and infections. Therefore, we longitudinally studied the impact of mode of delivery on the nasopharyngeal microbiota development from birth until six months of age in a healthy, unselected birth cohort of 102 children (n = 761 samples. Here, we show that the respiratory microbiota develops within one day from a variable mixed bacterial community towards a Streptococcus viridans-predominated profile, regardless of mode of delivery. Within the first week, rapid niche differentiation had occurred; initially with in most infants Staphylococcus aureus predominance, followed by differentiation towards Corynebacterium pseudodiphteriticum/propinquum, Dolosigranulum pigrum, Moraxella catarrhalis/nonliquefaciens, Streptococcus pneumoniae, and/or Haemophilus influenzae dominated communities. Infants born by Caesarian section showed a delay in overall development of respiratory microbiota profiles with specifically reduced colonization with health-associated commensals like Corynebacterium and Dolosigranulum, thereby possibly influencing respiratory health later in life.

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

    Science.gov (United States)

    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.

  17. Effects of random tooth profile errors on the dynamic behaviors of planetary gears

    Science.gov (United States)

    Xun, Chao; Long, Xinhua; Hua, Hongxing

    2018-02-01

    In this paper, a nonlinear random model is built to describe the dynamics of planetary gear trains (PGTs), in which the time-varying mesh stiffness, tooth profile modification (TPM), tooth contact loss, and random tooth profile error are considered. A stochastic method based on the method of multiple scales (MMS) is extended to analyze the statistical property of the dynamic performance of PGTs. By the proposed multiple-scales based stochastic method, the distributions of the dynamic transmission errors (DTEs) are investigated, and the lower and upper bounds are determined based on the 3σ principle. Monte Carlo method is employed to verify the proposed method. Results indicate that the proposed method can be used to determine the distribution of the DTE of PGTs high efficiently and allow a link between the manufacturing precision and the dynamical response. In addition, the effects of tooth profile modification on the distributions of vibration amplitudes and the probability of tooth contact loss with different manufacturing tooth profile errors are studied. The results show that the manufacturing precision affects the distribution of dynamic transmission errors dramatically and appropriate TPMs are helpful to decrease the nominal value and the deviation of the vibration amplitudes.

  18. Exposure to serotonin adversely affects oligodendrocyte development and myelination in vitro.

    Science.gov (United States)

    Fan, Lir-Wan; Bhatt, Abhay; Tien, Lu-Tai; Zheng, Baoying; Simpson, Kimberly L; Lin, Rick C S; Cai, Zhengwei; Kumar, Praveen; Pang, Yi

    2015-05-01

    patterns of contactin-associated protein (Caspr) clustering were observed at the sites of Node of Ranvier, suggesting that 5-HT exposure may affect other axon-derived factors for myelination. In summary, this is the first study to demonstrate that manipulation of serotonin levels affects OL development and myelination, which may contribute to altered neural connectivity noted in SSRIs-treated animals. The current in vitro study demonstrated that exposure to high level of serotonin (5-HT) led to aberrant oligodendrocyte (OL) development, cell injury, and myelination deficit. We propose that elevated extracellular serotonin levels in the fetal brain, such as upon the use of selective serotonin reuptake inhibitors (SSRIs) during pregnancy, may adversely affect OL development and/or myelination, thus contributing to altered neural connectivity seen in Autism Spectrum Disorders. OPC = oligodendrocyte progenitor cell. © 2014 International Society for Neurochemistry.

  19. Hypoxic level and duration differentially affect embryonic organ system development of the chicken (Gallus gallus).

    Science.gov (United States)

    Zhang, H; Burggren, W W

    2012-12-01

    Hypoxia inhibits avian embryonic development, as well as increases embryonic mortality. However, the key organ systems affected by hypoxia, and their critical windows for development, are poorly understood. Consequently, chicken embryos were continuously exposed to 3 levels of oxygen (21, 15, or 13% O(2)) throughout d 0 to 10, d 11 to 18, or d 0 to 18 of incubation, followed by morphometric and blood physiological measurements. Hypoxia occurring early during incubation (d 0 to 10) had larger effects on embryonic mortality and organ growth than hypoxia occurring at later stages (d 10 to 18). Growth of the heart and chorioallantoic membrane was stimulated by chronic hypoxia, whereas the lung, brain, eye, liver, stomach, beak, and toes showed no disruption. Sustained hypoxia from the beginning of incubation decreased blood hemoglobin, hematocrit, and red blood cell concentration of embryos at d 10, but the values among hypoxic and normoxic groups were not significantly different at d 18. Blood partial pressure of O(2) and partial pressure of CO(2) were dependent upon incubation O(2) level at a given day of development. These results indicated that either modest hypoxia (15% O(2)) throughout development, or hypoxia at any level during the late stages (d 11 to 18), increased the heart and chorioallantoic membrane weight, which partly compensated for the detrimental effects of hypoxia on embryonic development. We conclude that the first half of embryonic development contained the critical windows for the detrimental effects of hypoxia, and the second half contained the critical windows for the compensatory response of hypoxia in key organs.

  20. A periodontal ligament driven remodeling algorithm for orthodontic tooth movement.

    Science.gov (United States)

    Chen, Junning; Li, Wei; Swain, Michael V; Ali Darendeliler, M; Li, Qing

    2014-05-07

    While orthodontic tooth movement (OTM) gains considerable popularity and clinical success, the roles played by relevant tissues involved, particularly periodontal ligament (PDL), remain an open question in biomechanics. This paper develops a soft-tissue induced external (surface) remodeling procedure in a form of power law formulation by correlating time-dependent simulation in silico with clinical data in vivo (pplan for sophisticated orthodontic treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.