SEARCH · PubMed Health

Results for “Tooth”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33Linked to original sources

PubMed2003

Autogenous free tooth transplantation with a two-stage operation technique.

If tooth transplantation is to succeed, it is crucial to preserve the vitality of the cells on the root surface of the tooth transplant. Insufficient postoperative nutrition to the cells on the root surface of the tooth transplant was thought to contribute to their devitalization of these cells. Impaired nutrition may be a result of poor contact between the recipient bed and the root surface of the transplanted tooth, and development of an interposed blood clot. To improve postoperative nutrition to the root surface cells, teeth were transplanted to the recipient beds in which the tissues were regenerated during a 14 day period, i.e., using the two-stage transplantation technique. In a clinical study of this technique, a total of 95 autogenous teeth with fully developed roots were transplanted in 84 patients, and examined both clinically and radiographically for up to 13 years after the transplantation. In a dog model, a comparative experimental study was made between teeth transplanted to beds left to heal for 5 days and teeth transplanted to beds prepared immediately before the transplantation. The clinical study showed a low prevalence of tooth graft loss and root resorption even when infection of the root canal occurred. Periodontal attachment loss of less than 3 mm was found in 97% of 6 defined surfaces around the transplanted teeth. Transplanted teeth which were later extracted were often hypermobile, and signalled pain when provoked with heavy loading. Excessive extraction trauma, fixation failure, and excessive plaque accumulation after transplantation were all shown to be detrimental to tooth transplant. Transplanted teeth were used as abutments for fixed partial dentures and provided the necessary dental support for crowns and bridges even in patients with atrophic alveolar bone. The experimental histological study showed no differences between test and control teeth in terms of the prevalence of root resorption, which was suspected to be caused by traumatic injuries to the roots during extraction and non-rigid fixation of the transplanted teeth.

Age Factors↗

PubMed2001

Traditional tooth bud gouging in a Ugandan family: a report involving three sisters.

It has been reported in the literature that some rural populations of Sub-Saharan and Eastern Africa and other isolated areas around the world, practise gouging or enucleation of primary tooth buds to cure childhood illnesses. The unerupted primary canine tooth bud is believed to be the cause of febrile illness, diarrhoea, and vomiting; prevalent in infants in these areas of the world. Tooth bud gouging has implications for the developing dentition, and is a potential risk to the health and life of the child. Reported prevalence ranges from 22%-90%. From the information in this case report, the practise of tooth bud gouging is no longer confined to rural areas and may well be performed by communities that have emigrated to the UK. The three sisters described, now resident in the UK, suffered tooth gouging in a city clinic in Uganda. The damage caused to the primary and permanent dentition is described and treatment planning and options are suggested for each case to restore structure and function. Appropriate provision of healthcare and education could avoid the potential long-term damage to the health of the child and their developing dentition by the practise of tooth bud gouging, whether it occurs in the developing or developed world.

Child↗

PubMed2001

Congenital tooth anomalies and malocclusions: a genetic link?

The aim of the present study was to investigate putative relationships between different malocclusions such as Class III and Class II division 1, and congenital tooth anomalies. Two-hundred Class III and 215 Class II division 1 patients were examined for the presence of any of the following congenital tooth anomalies: maxillary incisor hypodontia, maxillary canine impaction, transpositions, supernumerary teeth, and tooth agenesis. Their occurrence rates were then calculated as a percentage of the total sample and were compared for statistical differences. The results revealed no statistical difference (P > 0.05) in the occurrence rates of upper lateral incisor agenesis, peg-shaped laterals, impacted canines, or supernumerary teeth between the Class III and the Class II division 1 malocclusions. When the occurrence rate of all congenital tooth anomalies was compared between the two malocclusions, Class III subjects showed significantly higher rates (P < 0.05). Comparison with published surveys on general populations showed similar occurrence rates. It can be concluded that subjects with Class III and Class II division 1 malocclusions show patterns of congenital tooth anomalies similar to those observed in the general population. Congenital tooth anomalies may represent another criterion for the study of malocclusion, with respect to their origin and development.

Adolescent↗

PubMed2002

Tissue engineering of complex tooth structures on biodegradable polymer scaffolds.

Tooth loss due to periodontal disease, dental caries, trauma, or a variety of genetic disorders continues to affect most adults adversely at some time in their lives. A biological tooth substitute that could replace lost teeth would provide a vital alternative to currently available clinical treatments. To pursue this goal, we dissociated porcine third molar tooth buds into single-cell suspensions and seeded them onto biodegradable polymers. After growing in rat hosts for 20 to 30 weeks, recognizable tooth structures formed that contained dentin, odontoblasts, a well-defined pulp chamber, putative Hertwig's root sheath epithelia, putative cementoblasts, and a morphologically correct enamel organ containing fully formed enamel. Our results demonstrate the first successful generation of tooth crowns from dissociated tooth tissues that contain both dentin and enamel, and suggest the presence of epithelial and mesenchymal dental stem cells in porcine third molar tissues.

Absorbable Implants↗

PubMed2000

Dynamics of tooth formation and replacement in the zebrafish (Danio rerio) (Teleostei, Cyprinidae).

We have used three-dimensional reconstructions from serial sections as well as cleared and stained specimens to infer patterning of the pharyngeal dentition throughout ontogeny in the zebrafish. Each pharyngeal tooth has been monitored from its initiation to its complete disappearance (resorption and shedding). We have identified tooth families and have studied the persistence of the pattern through successive replacements. Teeth arise in two seemingly independent clusters, a ventral and a dorsal cluster, with differing patterning features. The ventral cluster consists of one row of five teeth in which a tooth is first initiated in position four, and subsequent teeth in adjacent positions, posterior and anterior to it. Replacement teeth in odd and even positions are initiated simultaneously during successive odontogenic waves but differ in generation number according to the timing of appearance of the first-generation tooth, i.e., the founder of the tooth family. Up to four teeth of a single tooth family are simultaneously present in early juveniles of which two are usually "co-functional." The number of teeth per tooth family is reduced in older juveniles and adults, reflecting a slowing down of the replacement rate. The consistent way in which the pattern is established and maintained during ontogeny calls for research of the presence of specific molecular controls.

Animals↗

PubMed2003

Tooth-root form and function in platyrrhine seed-eaters.

Research into the functional and adaptive basis of tooth crown form has provided a useful framework for the inference of diet in extinct primates. However, our understanding of variation in tooth-root form is limited. Studies within the clinical literature emphasize the influence of tooth-root surface area on stress resistance, but it is not known if root form has diversified during primate evolution in relation to dietary specialization. This hypothesis was tested by quantifying maxillary canine and postcanine tooth-root surface areas in four platyrrhine species that differ in the material properties of their diet: Cebus apella, Cebus albifrons, Chiropotes satanas, and Pithecia pithecia. Pairwise comparisons between closely related taxa support predictions based on dietary differences. Taxa that regularly consume resistant seeds (Cebus apella and Chiropotes satanas) exhibit significantly larger relative surface area values for those teeth used in seed processing than closely related taxa that consume resistant foods less often (Cebus albifrons and Pithecia pithecia). Additionally, relative molar-root surface area appears to be greater in Pithecia than in Chiropotes, as predicted from the more folivorous diet of Pithecia. Tooth-root surface area was also found to vary along the tooth row and should therefore have a significant influence on antero-posterior bite-force gradients. The results of this study suggest a close relationship between tooth-root form and patterns of occlusal loading. Further elucidation of this relationship could improve our inferences of diet in extinct taxa, and augment research into the mechanics and evolution of feeding.

Animals↗

PubMed1982

Allometric scaling in the dentition of primates and prediction of body weight from tooth size in fossils.

Tooth size varies exponentially with body weight in primates. Logarithmic transformation of tooth crown area and body weight yields a linear model of slope 0.67 as an isometric (geometric) baseline for study of dental allometry. This model is compared with that predicted by metabolic scaling (slope = 0.75). Tarsius and other insectivores have larger teeth for their body size than generalized primates do and they are not included in this analysis. Among generalized primates, tooth size is highly correlated with body size. Correlations of upper and lower cheek teeth with body size range from 0.90-0.97, depending on tooth position. Central cheek teeth (P44 and M11) have allometric coefficients ranging from 0.57-0.65, falling well below geometric scaling. Anterior and posterior cheek teeth scale at or above metabolic scaling. Considered individually or as a group, upper cheek teeth scale allometrically with lower coefficients than corresponding lower cheek teeth; the reverse is true for incisors. The sum of crown areas for all upper cheek teeth scales significantly below geometric scaling, while the sum of crown areas for all lower cheek teeth approximates geometric scaling. Tooth size can be used to predict the body weight of generalized fossil primates. This is illustrated for Aegyptopithecus and other Eocene, Oligocene, and miocene primates. Regressions based on tooth size in generalized primates yield reasonable estimates of body weight, but much remains to be learned about tooth size and body size scaling in more restricted systematic groups and dietary guilds.

Animals↗

PubMed2004

Neural crest contribution to mammalian tooth formation.

The cranial neural crest cells, which are specialized cells of neural origin, are central to the process of mammalian tooth development. They are the only source of mesenchyme able to sustain tooth development, and give rise not only to most of the dental tissues, but also to the periodontium, the surrounding tissues that hold teeth in position. Tooth organogenesis is regulated by a series of interactions between cranial neural crest cells and the oral epithelium. In the development of a tooth, the epithelium covering the inside of the developing oral cavity provides the first instructive signals. Signaling molecules secreted by the oral epithelium 1) establish large cellular fields competent to form a specific tooth shape (mono- or multicuspid) along a proximodistal axis; 2) define an oral (capable of forming teeth) and non-oral mesenchyme along a rostrocaudal axis; and 3) position the sites of future tooth development. The critical information to model tooth shape resides later in the neural crest-derived mesenchyme. Cranial neural crest cells ultimately differentiate into highly specialized cell types to produce mature dental organs. Some cranial neural crest cells located in the dental pulp, however, maintain plasticity in their developmental potential up to postnatal life, offering new prospects for regeneration of dental tissues.

Animals↗

PubMed2005

Tissue interactions in the regulation of axon pathfinding during tooth morphogenesis.

Like many other organs, the tooth develops as a result of the epithelial-mesenchymal interactions. In addition, the tooth is a well-defined peripheral target organ for sensory trigeminal nerves, which are required for the function and protection of the teeth. Dental trigeminal axon growth and patterning are tightly linked with advancing tooth morphogenesis and cell differentiation. This review summarizes recent findings on the regulation of dental axon pathfinding, which have provided evidence that the development of tooth trigeminal innervation is controlled by epithelial-mesenchymal interactions. The early dental epithelium possesses the information to instruct tooth nerve supply, and signals mediating these interactions are part of the signaling networks regulating tooth morphogenesis. Tissue interactions, thus, appear to provide a central mechanism of spatiotemporally orchestrating tooth formation and dental axon navigation and patterning.

Animals↗

PubMed2001

The emotional effects of tooth loss in partially dentate people attending prosthodontic clinics in dental schools in England, Scotland and Hong Kong: a preliminary investigation.

AIM: To compare the emotional effects of tooth loss in three partially dentate populations. DESIGN: A questionnaire survey. MATERIALS AND METHODS: A questionnaire was completed by 150 partially dentate subjects undergoing routine prosthodontic care at Guy's, King's and St Thomas's Dental Institute, London; the Dental School, Dundee, Scotland; and the Faculty of Dentistry, University of Hong Kong. Data were analysed using the Chi-square test. RESULTS: Forty nine per cent of all participants reported difficulties in accepting the loss of some of their teeth. People from Dundee were less likely to have difficulties accepting tooth loss (P = 0.001). People from London took longer to come to terms with their tooth loss and were more likely to feel less confident (P < 0.001). Fifty five per cent of all participants restricted their choice of foods and 54 per cent had not enjoyed their food as much as before. Fewer people in Dundee restricted their choice of food (P < 0.001) and were more likely to enjoy their food (P = 0.009). People in Hong Kong were most likely to restrict their choice of food (P = 0.006). Thirty five percent of all subjects felt unprepared for the effects that tooth loss had upon them. People in Hong Kong were more prepared for tooth loss than those in Dundee and London (P = 0.003). In addition, they were less concerned about leaving their dentures out overnight (P = 0.024). CONCLUSIONS: The emotional effects of tooth loss were significant in all groups. People from London took longer to come to terms with their tooth loss.

Attitude to Health↗

PubMed1986

Changes in heated and in laser-irradiated human tooth enamel and their probable effects on solubility.

Enamel of intact human teeth laser irradiated in vitro under certain conditions is known to have less subsurface demineralization than unirradiated enamel on exposure to acid; consequently, the potential use of laser irradiance to reduce caries is apparent. The laser-induced physical and/or chemical changes that cause this reduced subsurface demineralization are not known. A laser-irradiated tooth enamel surface will have a temperature gradient that decreases towards the dentin junction. Dependent on irradiant conditions, the temperature may range from greater than 1400 degrees C at the surface to near normal at the dentin-pulp junction. Along this steep temperature gradient, different compositional, structural, and phase changes in the tooth enamel are to be expected. Identification of changes occurring along this gradient has bearing on understanding the dissolution reduction mechanism and, in turn, optimizing its effect. Changes in laser-irradiated material from the highest temperature region have been characterized, but those occurring in sequential layers of decreasing temperatures have not. Since the laser-induced changes are expected to primarily arise from localized heating, previously reported thermally induced changes in tooth enamel on heating in conventional furnaces were utilized to infer corollary changes along the gradient in laser-irradiated tooth enamel. These thermally inferred changes which resulted in modifications in the tooth enamel apatite and/or newly formed phases were correlated with their probable effects on altering solubility. A temperature gradient range from 100-1600 degrees C was considered with subdivisions as follows: I, 100-650 degrees C; II, 650-1100 degrees C; and III, greater than 1100 degrees C. Two of the products formed in range III, alpha-Ca3(PO4)2 and Ca4(PO4)2O, and also identified in the fused-melted material from laser-irradiated tooth enamel, are expected to markedly increase solubility in those regions that contain considerable amounts of these compounds. Products and changes occurring in range II, separate phases of alpha- and/or beta-Ca3(PO4)2 and a modified phase of apatite, may increase or decrease the solubility depending on the Ca/P ratio and the resultant amounts of alpha-, beta-Ca3(PO4)2 formed. Modifications in tooth enamel apatite effected in range I are expected to decrease its solubility; the formation of pyrophosphate in this range may have a substantial effect on reducing the solubility rate.(ABSTRACT TRUNCATED AT 400 WORDS)

Biological Transport, Active↗

PubMed1998

Expression of E- and P-cadherin during tooth morphogenesis and cytodifferentiation of ameloblasts.

Cell-cell adhesion is fundamental in morphogenesis and is known to be mediated by several groups of cell adhesion molecules. Cadherins are a group of such molecules involved in the Ca2+-dependent cell-cell adhesion mechanism and are found in most kinds of tissue. In this study using indirect immunofluorescence microscopy, we analyzed the distribution of two kinds of cadherins, E- and P-cadherin, in developing tooth germs. In the molar tooth germs at the early bud stage, marginal cells of the epithelial tooth bud expressed both E- and P-cadherin, whereas central cells expressed only E-cadherin. At the cap stage, in addition to the cells of the inner and outer enamel epithelium, which outline the enamal organ, cells of the enamel knot, which is thought to control tooth morphogenesis, strongly expressed P-cadherin. The expression of P-cadherin was prominent in the inner enamel epithelium during the early to mid bell stage, and was also evident in the non-dividing cell masses at future cusp tips, which are the so-called secondary enamel knots. In the tooth germ at the late bell stage when the cells of the inner enamel epithelium began to polarize to differentiate into ameloblasts, the polarizing ameloblasts lost P-cadherin and strongly expressed E-cadherin. However, E-cadherin was also lost from polarized ameloblasts at later stages. The stratum intermedium and the stellate reticulum were E-cadherin positive from the bell stage onward even at the stages when the ameloblasts became E-cadherin negative again. These results suggest that the differential expression of E- and P-cadherin during morphogenetic stages plays a role in the regulation of tooth morphogenesis, whereas alteration of E-cadherin expression during later stages of tooth development is related to differentiation and function of the ameloblasts and other cells supporting amelogenesis.

Ameloblasts↗

PubMed2005

Tooth development in vitro in two teleost fish, the cichlid Hemichromis bimaculatus and the cyprinid Danio rerio.

A technique for organotypic in vitro culture with serum-free medium was tested for its appropriateness to mimic normal odontogenesis in the cichlid fish Hemichromis bimaculatus and the zebrafish Danio rerio. Serial semithin sections were observed by light microscopy to collect data on tooth patterning and transmission electron microscopy was used to compare cellular and extracellular features of tooth germs developing in vitro with the situation in vivo. Head explants of H. bimaculatus from 120 h post-fertilization (hPF) to 8.5 days post-fertilization (dPF) and of zebrafish from 45 hPF to 79 hPF and adults kept in culture for 3, 4 or 7 days revealed that tooth germs developed in vitro from explants in which the buccal or pharyngeal epithelium was apparently undifferentiated and, when present at the time of explantation, they continued their development up to a stage of attachment. In addition, the medium allowed the morphogenesis and cytodifferentiation of the tooth germs similar to that observed in vivo and the establishment of a dental pattern (place and order of tooth appearance and of attachment) that mimicked that in vivo. Organotypic culture in serum-free conditions thus provides us with the means of studying epithelial-mesenchymal interactions during tooth development in teleost fish and of analysing the genetic control of either mandibular or pharyngeal tooth development and replacement in these polyphyodont species. Importantly, it allows heads from embryonically lethal (zebrafish) mutants or from early lethal knockdown experiments to develop beyond the point at which the embryos normally die. Such organotypic culture in serum-free conditions could therefore become a powerful tool in developmental studies and open new perspectives for craniofacial research.

Animals↗

PubMed1992

Effect of tooth temperature on activities of slowly adapting periodontal mechanoreceptors in the cat.

The mass response of a nerve bundle and the unitary discharges from a functional single nerve fibre evoked by mechanical stimulation of the upper canine tooth were recorded from the superior alveolar nerves of 10 anaesthetized cats. When the pulpal cavity of the mechanically stimulated tooth was perfused with a 0.9% NaCl solution at temperatures from 10 to 45 degrees C, the mass response of the nerve bundle to that stimulation increased linearly with the rise in perfusate temperature (hereafter, tooth temperature). In the unitary discharge recordings, the activities of 30 (88%) of 34 slowly adapting periodontal mechanosensitive units were modulated by tooth temperature. The optimal temperature, at which the periodontal mechanoreceptor shows extreme excitation by mechanical tooth stimulation, was distributed widely from 10 to < or = 45 degrees C with a peak at < or = 45 degrees C. A shift in tooth temperature away from the optimal value caused a decrease in, or sometimes the disappearance of, the response. This decrease was the result of the decrease in the excitability of the periodontal mechanoreceptor; i.e. an increase in threshold stimulus intensity and a shortening of the adaptation time to sustained pressure applied to the tooth.

Adaptation, Physiological↗

PubMed1978

X-ray fluorescence analysis of lead in teeth of urban children in situ: correlation between the tooth lead level and the concentration of blood lead and free erythroporphyrins.

The tooth lead level of 30 lead-exposed children was measured in situ using an X-ray fluorescence technique. The tooth lead concentration divided by the child's age correlated with the free erythroporphyrin (FEP) (r = 0.51) and the blood lead levels (r = 0.31). The mean tooth lead concentrations of 10 Class IV children (FEP greater than or equal to 190 micrograms/100 ml; blood lead 30-80 micrograms/ml) was 14.5 +/- 5.5 ppm/year. Reexamination of the histories of children who had been classified as Class II or III, but who had tooth lead concentrations within 1 SD of the Class IV level, indicated that many of these children could also be considered to be Class IV children. When the x-ray fluorescence technique was used to screen an urban population of 300 children, the tooth lead values indicated that 72% of the children had been exposed to low levels of environmental lead. Six percent of the children were found to have tooth lead concentrations in excess of 9 ppm/year and within 1 SD of the mean value exhibited by Class IV children. These children were considered to have a high body lead burden. The percentage of children having an elevated tooth lead level is similar to the number previously reported using exfoliated deciduous teeth.

Child↗

PubMed1987

The tooth contact sound as an analogue of the "quality of occlusion".

This study investigated the relationship between the tooth contact sound and its wave pattern, and the interrelationships of the components of the wave pattern. The hypothesis that the tooth contact sound and features of its wave pattern are analogues of the quality of occlusion was also investigated. The sample consisted of 133 subjects. By means of a standardized technique, tooth contact sounds produced during habitual closure were recorded and used to produce wave patterns. Statistical tests were used to determine whether significant relationships existed between selected gnathosonic parameters and aspects of the quality of occlusion that had been assessed by clinical examination. The findings of this study lead to the following conclusions: The measures of wave pattern duration (ALPHDUR and TOTDUR) are significantly related to the amplitude of the wave pattern (or the loudness of the tooth contact sound). Thus, allowance should be made for variations in amplitude when considering the relationship between measures of wave pattern duration and other factors. The measurement of ALPHDUR is independent of the recording equipment used to produce the wave pattern. ALPHDUR may therefore be of use in the comparison of gnathosonic data that have been produced by different recording techniques. ALPHDUR is the wave pattern component that bears the strongest relationship to the categorized tooth contact sound. In some respects, three gnathosonic parameters (tooth contact sound category, ALPHDUR [ADJ], AND AMPL) might be considered to be analogous of the quality of occlusion. Of these, the subjectively assessed tooth contact sound would appear to have some practical application in routine dental practice.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Anterior maxillary advancement using tooth-supported distraction osteogenesis.

PURPOSE: This study used the principle of distraction osteogenesis to advance the anterior maxilla of the dog using a totally tooth-supported distraction device. MATERIALS AND METHODS: After an anterior maxillary osteotomy, the distraction device was activated 0.5 mm every 12 hours to advance the anterior segment 10 mm in 10 days. RESULTS: Serial tooth and radiographic measurements indicated that on the 10th day the average tooth advancement was 8.4 mm +/- 1.5 mm and the average skeletal advancement was 4.0 mm +/- 1.5 mm. After 6 weeks the average tooth advancement was 7.2 +/- 1.6 mm and the average skeletal advancement was 3 +/- 1.3 mm. At 3 months the tooth advancement was 6.2 +/- 1.5 mm and at 6 months the tooth advancement was 5.0 +/- 1.1 mm. Bone healing was present in all animals. CONCLUSION: This results of this study indicate that a tooth-borne maxillary distraction device will result in significantly greater dental movement than skeletal movement and that skeletal fixation may be needed for appliances used to advance the maxilla.

Animals↗

PubMed2005

Active and passive smoking and tooth loss in Japanese women: baseline data from the osaka maternal and child health study.

PURPOSE: Many studies have shown a positive association between cigarette smoking and oral diseases. Few studies, however, have focused on the relationship between passive smoking exposure and oral health in adults. We investigated the association of active and passive smoking exposure with tooth loss in Japan. METHODS: Study subjects were 1002 pregnant women. Tooth loss was defined as previous extraction of one or more teeth. Adjustment was made for age, gestation, parity, family income, education, and body mass index. RESULTS: Of the 1002 subjects, 256 women had lost one or more teeth. Current light smoking was independently related to an increased prevalence of tooth loss, showing a significant exposure-related association with smoking status. A significant positive association of 8 or more pack-years of smoking with the prevalence of tooth loss was observed. Also, a significant positive relationship was found between current heavy passive smoking at home and tooth loss, but not with pack-years of passive smoking at home. No measurable association between passive smoking exposure at work and tooth loss was indicated. CONCLUSIONS: The present findings suggest that passive as well as active smoking may be associated with an increased prevalence of tooth loss in Japanese young adult women.

Adult↗