SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The state of inclination and the change under various conditions of the imaginary axis of the tooth crown of upper jaw and lower jaw right and left first molar can be determined by the measuring apparatus and method of this study. 2. The measurement error of this method was not more than 0.1 degree. This value was sufficient for the purpose of this study.
Single-tooth implants have become a predictable treatment option. Acceptable esthetics are an important factor for success. The emergence profile of the crown in the cervical region is complicated by the discrepancy between the round shape and the small diameter of the implant and the desired anatomical shape of the crown. An abutment on an implant has to provide this natural looking emergence profile and has to support the crown. Custom-shaped abutments are the best option for this task. Many items influence the design. This article discusses a set of guidelines for the design of custom-shaped abutments for single-tooth implants.
Altogether 2159 pregnancies among black and white Americans in the Collaborative Perinatal Study and dental casts from the children at the age of 5-12 years were studied to find out the effect of maternal smoking on deciduous tooth crown growth. Minor crown size reduction (2-3%) in some dimensions was found in children whose mothers had smoked during pregnancy. The possible change in dimensions seems to be influenced by sex, race and smoking habit. The critical time periods of the gestational development (16th to 19th) weeks would possibly appear from these data to be targeted by the detrimental effect of maternal smoking. It is concluded that deciduous tooth sizes seem to be greatly unaffected when compared to reduction in birthweight.
In females with numerical and/or structural aberration of the X chromosome as in Turner's syndrome, somatic development deviates from the normal pattern. The aim of the present study was to investigate the tooth crown dimensions, and report the size of the alveolar arch of the maxilla and the mandible of patients with Turner's syndrome. The study population consisted of 29 girls with Turner's syndrome and 30 healthy female controls. All mesiodistal dimensions were significantly smaller in Turner's syndrome compared with those of normal controls. The labiolingual dimensions were smaller in the patient group with the exception of the canines and the lower central incisors. The alveolar arch of the maxilla was narrower and of normal length, but the mandibular arch was shorter and broader. Orthodontic anomalies were found more frequent and serious of patients with Turner's syndrome. Our examination showed the importance of early diagnosis of oral anomalies as well as dental treatment of patients with Turner's syndrome.
UNLABELLED: To evaluate the effects of preadjusted bracket base shape, the morphology of tooth surface where bracket locates, and the suitability relevant to location of bracket on the preadjusted edgewise appliance technique. 1 vertical curve and 3 horizontal curves of the clinical crown surface of anterior teeth and bicuspid teeth were measured with the precise contour instrument on the 60 plaster models of the subjects who have normal occlusion in Sichuan province. It was found that variation of identical curve exists at the different heights between the teeth and between the individuals; the surface of the central zone of tooth-crown gradually protrudes from incisors to bicuspid teeth in the vertical direction, and the mesial contour of cuspid is more prominent than the distal in the horizontal direction. CONCLUSION: The 4 mm X 3 mm contour of the vestibular central zone of identical tooth-crown in different individuals is fairly stable; it is suitable for the location of preadjusted brackets. The vertical shifts of brackets could change the preadjusted torque value and the design of cuspid bracket should have the distinction between mesial and distal shape.
Sexual dimorphism in the crown components in the second deciduous molar (dm2) and the first permanent molar (M1) of the dental casts taken from Chinese living in Kaohsiung (Taiwan) was investigated. Mesiodistal and buccolingual crown diameters, and 4 main-cusp sizes in the maxillary molars and mesiodistal diameters of the trigonid and talonid in the mandibular molars were measured using a digital caliper (0.01 mm). Percentage sexual differences were calculated. With the exception of trigonid mesiodistal diameters, the mean values of males were larger than females. In both of dm2 and M1 the mean values of the trigonid mesiodistal diameters were slightly larger in females than in males, but the differences were not significant. Percentage sexual dimorphism was smaller in the mesiodistal diameters than in the buccolingual in both dm2 and M1. The crown components showed larger sexual difference in dm2 than in M1, while in the maxilla the external crown size showed larger sexual difference in M1 than in dm2. The buccal cusps showed larger sexual difference than the lingual in the maxillary molars and the talonid showed larger sexual difference than the trigonid in the mandibular. Sexual dimorphism of dm2 and M1 in their crown components displayed similar pattern, although the different degree was noted. This result is thought to relate to the fact these molars belong to the first dentition embryologically.
Tissue engineering of teeth requires the coordinated formation of correctly shaped crowns, roots, and periodontal ligament. Previous studies have shown that the dental mesenchyme controls crown morphogenesis and epithelial histogenesis during tooth development in vivo, but little is known about the inductive potential of dissociated mesenchymal cells used in ex vivo cultures. A 2-step method is described in which, by using different types of reassociations between epithelial and mesenchymal tissues and/or cells from mouse embryos, reassociations were cultured in vitro before in vivo implantation. In vitro, the reassociated tissues developed and resulted in tooth-like structures that exhibited normal epithelial histogenesis and allowed the functional differentiation of odontoblasts and ameloblasts. After implantation, the reassociations formed roots and periodontal ligament, the latter connected to developing bone. The shape of the crown, initially suspected to depend on the integrity of the mesenchyme, could be modulated by adjusting the number of dissociated mesenchymal cells reassociated with the epithelial compartment. Based on these results, we propose a refined strategy for tooth tissue engineering that may help to eventually generate morphologically defined teeth.
Teeth are probably meristic units and crown morphogenesis leads to tooth specific distribution of functional cells. Since heterodonty is derived from homodonty, one way to understand tooth morphogenesis would be to unravel the involved phenomena in homodont species and then to characterize the "put up job" of evolution leading to species specific dentitions with particular functional abilities. Interaction of paleontologists and developmental biologists should be initiated. My naive "developmental" point of view will illustrate only one facet of mouse tooth morphogenesis and cytodifferentiation. The main concern will be to try to discriminate between known facts and speculations, between hypotheses and anticipated or deduced certitudes, to call attention to conflicting data, to suggest some further investigations and to advocate the point of view that molecular interpretations should be founded on indisputable morphological data.
Explore the source record for details and available documents.
Marginal adaptation of the crown edge has been considered as primary and significant factor of prevention of secondary caries and periodontal disease on carryig tooth. There has been a clear dependence between hunting the periodontal tissue and the quality of edge closing of the crown. If we position subgingivaly the crown which clinically shows a good adoptiveness marginally and at the same time we position marginal crease in the ginguival sucus that should rush the accumulation of the plaque. The bacteries in the plaque would cause the inflammation of ginguive. The end of the crown edge in gingival sucus would cause chronic inflammation at ginguival tissue. The existence of transit zone that includes the crown edge, prepared tooth and dental cement became important if the crown edge has been positioned subgingivaly. If the crown edge ends in the ginguival sucus, the tooth meat is constantly being irritated that results with different degrees of inflammations. In many cases it causes ginguival dislocation. The possibility of clinical control of marginal positioning of subgingivaly positioned crown edge on demarcation line does not exist in terminal phase of cementing. The crown cement can be substratum of bacterial receptiveness and the plaque accumulation in the ginguival sucus. The procedure of cementing is an important cause of incomplete edge closing of the crown on the demarcation line. The form of demarcation line determine the form and the width of crown. They are favorising and degrading the level of marginal adaptations. The existing of horizontal discrepancy at the relation of based tooth--the crown edge is unavoidable. The question is if the amount of this discrepancy fits the assumed biological optimum.
A simple technique is presented in which an existing crown can be replaced on a broken endodontically treated tooth in one appointment. This can reduce the working time and expense required for a new crown.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Permanent tooth sizes in 15 Finnish females with a 45,X/46,XX chromosome constitution were measured and compared with those of normal females, first-degree female relatives and 45,X females. Mesiodistal crown diameters of the 45,X/46,XX mosaic females were smaller than those of normal females but similar to those of females with pure 45,X chromosome constitution. Labiolingual crown diameters of the 45,X/46,XX mosaics were near normal, being consistently larger than those of 45,X females. The mesiodistal crown sizes are consistent with a decrease in enamel thickness in 45,X/46,XX mosaic females. The difference in labiolingual dimension between teeth of 45,X/46,XX mosaic females and 45,X females may relate to a gradual normalization of growth when normal 46,XX cells are mixed with defective 45,X cells.
Explore the source record for details and available documents.