Sex differences in the chronology of deciduous tooth emergence in white and black children.
Explore the source record for details and available documents.
Animals↗
SEARCH · Search PubMed
Results for “Tooth Eruption”
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.
Deciduous tooth chronology in the mandible of the domestic pig.
Fetuses of known age, collected from 20 days' gestation to term, were used to characterize the chronology of deciduous tooth development within the right mandible of swine. Tooth development was first observed at 32 days' embryonic development, with the differentiation of the deciduous third molar. Bud stages for the remaining deciduous teeth differentiated within the period of 32 to 38 days of embryonic development. Although the initial histological appearance of these teeth covered a short period of time, it was apparent that each tooth continued to develop at its own rate. The deciduous second incisor and first molar reached a stage of enamel formation by the 80th and 86th day of fetal development. This is a much later stage than previously recorded for beginning enamel formation. The stages of tooth development and enamel formation for each tooth are summarized. A previous report on the distribution of the dental lamina and deciduous tooth development in the mandible of the domestic pig combined with the information presented in this report on tooth chronology provide much of the information required for future studies using the domestic pig in dental research. A fetus observed at the 74th day of development demonstrated a tooth bud for the deciduous first premolar. The development of this tooth was followed closely throughout the remainder of fetal development with the cap stage representing its most definitive form at 110 days' development. The suggested deciduous origin for this tooth could result in a reevaluation of the nomenclature for the dental formula of swine.
Animals↗
Sexual differences in dental development and prediction of emergence.
The dental development of a genetically homogeneous French-Canadian group of children ranging in age from 2.5 to 19 years was evaluated from 5,437 panoramic radiographs by the method of Demirjian et al. The maturity of each mandibular tooth was evaluated individually. For each stage of each tooth, the developmental curves of boys and girls were compared. A common pattern was found for each tooth, namely the chronological similarity between boys and girls in the early stages of development and the advancement of girls over boys for the later stages. Development scores were given to the seven mandibular teeth. Up to five to six years of age, no difference was found in the timing of dental development between boys and girls, in contrast to the older ages where girls were always more developed than boys. When the emergence curve was plotted with developmental curves, a close relation was established between the stage of formation of all teeth and their emergence, hence the predictive value of the use of dental maturity curves in clinics.
Adolescent↗
Ethnic variability in the prevalence of submerged primary molars.
Dental submergence, linked primarily with tooth ankylosis, has been reported to have a possible genetic predisposition. The submergence of primary molars was examined in a sample of 1530 children, 2.5-13.5 yr old, appertaining to seven ethnic groups living in Israel. It was found that the frequency of submergence varied among the ethnic groups, and that, on the whole, it was considerably higher than that in North American children.
Adolescent↗
Sexual dimorphism in the emergence of the deciduous teeth.
Exact ages of emergence of the twenty deciduous teeth have been investigated on a longitudinal sample of 195 French-Canadian children (113 boys and 82 girls). A multivariate analysis of variance yielded a significant overall sex difference (p less than 0.0001). It has been found that the emergence of the deciduous dentition in boys is more precocious than that in girls by about one month; this difference is present at the emergence of the upper central incisor and is maintained henceforth. The only notable exception to this pattern is the emergence of the first molars. Results of the present study, combined with those of previous research, suggest that sexual dimorphism in the emergence of the deciduous teeth could be mediated through ethnic factors.
Age Factors↗
An autoradiographic study of periodontal development in the mouse.
Tritiated thymidine was injected into 10- and 13-day-old mice because at this age the third molar is at the appropriate stage of development. At set intervals, the mice were killed and the distribution of labeled cells within the dental papilla and follicle examined. The change in labeling index with time was measured for defined areas in the papilla and follicle. It was shown that, during the late bell stage of development, cells moved from the papilla into the follicle. It was concluded that the pulp, rather than the investing layer of the follicle, is the source of the periodontium and that growth of the pulp and periodontal tissues could generate an important force contributing to tooth eruption.
Analysis of Variance↗
An experimental study in dogs of transseptal fiber arrangement between teeth which have emerged in rotated or non-rotated positions.
Transseptal fibers of the periodontal ligament are thought to play a role in relapse after orthodontic derotation. The aim of this study was to compare the location of the attachment site and the arrangement of the transseptal fibers in rotated emerged and non-rotated emerged teeth. In five dogs, unilaterally, the first upper premolars were replaced into a rotated position, before emergence. Histological evaluation showed that transseptal fibers developed in the experimental as well as in the control specimens. In all cases, transseptal fibers bridged the shortest distance between two adjacent teeth. It was concluded that the attachment site of the transseptal fibers was not determined by the tooth anatomy itself, but by the tooth position and its orientation in the dental arch during transseptal fiber development.
Animals↗
Carbonate content in developing human and bovine enamel.
The present study describes the detailed changes in carbonate distribution throughout the different stages of development in human and bovine enamel, from early formation to maturation. Twenty-two human maxillary and mandibular deciduous anterior teeth and 46 bovine teeth were studied. The major mineral ions, calcium and phosphorus, were also analyzed to facilitate comparison of carbonate content with progressing mineralization. The results showed that as enamel matured and mineral concentration increased, carbonate concentration decreased. The observed decrease in percent carbonate per weight enamel mineral may be due to dilution by an influx of relatively carbonate-free mineral, and could, in part, explain the observed increase in crystallinity of enamel mineral as the tissue matures.
Aging↗
Initial acquisition of mutans streptococci by infants: evidence for a discrete window of infectivity.
Oral bacterial levels of 46 mother-child pairs were monitored from infant birth up to five years of age so that the acquisition of mutans streptococci (MS) by children could be studied. The initial acquisition of MS occurred in 38 children at the median age of 26 months during a discrete period we designated as the "window of infectivity". MS remained undetected in eight children (17%) until the end of the study period (median age of 56 mo). The levels of both MS and lactobacilli in saliva of mothers of children with and without MS were not significantly different. Comparisons between a caries-active cohort colonized by MS (nine of 38) and children without detectable MS revealed similar histories in terms of antibiotic usage, gestational age, and birth weight. Interestingly, half of the children between the ages of one and two years who were not colonized by MS were attended by caretakers other than the mother, while all of the caries-active children during this same time period were cared for by their mothers; the difference was statistically significant. Here we report for the first time that MS is acquired by infants during a defined period in the ontogeny of a child. Support for the notion of a discrete window of infectivity comes from other sources, including animal models.
Adult↗
Bone age determination in a paediatric population as an indicator of nutritional status.
The United Mission to Nepal Tansen Project is in the hill country, 300 km West of Kathmandu. This 40-year-old service centre's major emphasis has been on clinical and community medicine and education. Agronomy, forestry, water resources development, adult literacy, etc., have also been part of the project's outreach. We had long noted that the children of all of the various tribal groups in the area are small for their age as compared with children in developed countries. Fracture care X-rays were examined to reveal delay in ossification and in physeal closure. Using the standards found in the Radiographic Atlas of Skeletal Development of the Hand and Wrist, we quantified this apparent delay by determining the bone age of all patients presenting at the hospital with upper limb injuries requiring X-ray. The collection of data was limited to 100 days and to those under the age of 21. Two hundred and nineteen patients' data were analysed. We found that bone maturation delay was very common and often severe. The average bone age among the 219 was 28% below chronological age. That is, 60% of all fell two standard deviations below the norm: i.e. two-thirds of all 9 year olds had the expected skeletal development of 6 year olds in Boston, USA. Dental age was also analysed using deciduous tooth shedding and tooth eruption patterns. Dental age retardation averaged 21%, but a larger per cent had normal eruption dates. Other physical and sociological data were included in a questionnaire completed for each patient. Among the variables examined, poverty alone appeared to be the major mover. We believe that national small stature is a result of lifelong community dietary inadequacy.
Age Determination by Skeleton↗
Upper airway obstruction and craniofacial morphology.
Otolaryngologists are being asked with increasing frequency to assess adequacy of the upper airway and to treat upper airway obstructive problems in orthodontic patients. The incentive has been provided by recent studies that purport to relate upper airway obstruction to dental and craniomorphologic changes. It is hypothesized that prolonged oral respiration during critical growth periods in children initiates a sequence of events that commonly results in dental and skeletal changes. In the chronic mouth-breather excessive molar tooth eruption is almost a constant feature, causing a clockwise rotation of the growing mandible, with a disproportional increase in anterior lower vertical face height. Such increases in anterior lower vertical face height are often associated with retrognathia and open bites. Low tongue posture seen with oral respiration impedes the lateral expansion and anterior development of the maxilla. Otolaryngologists have the ability to objectively and accurately assess upper airway patency. Rhinometric assessment before and after application of topical nasal decongestant, in conjunction with clinical examination, provides valuable information regarding upper airway patency and the cause of any existing obstructive pathologic condition. Studies should be designed carefully to control the numerous variables that have an impact on the growing face of a young child so that meaningful data can be obtained in our own field regarding this challenging topic.
Child, Preschool↗
Expression patterns of RNAs for amelin and amelogenin in developing rat molars and incisors.
We have recently identified a novel RNA sequence in ameloblasts, coding for amelin (Cerny et al., 1996). In the present paper, its expression has been compared with that of amelogenin in developing incisors and molars of rats, by means of in situ hybridization of paraffin sections. The RNAs for both amelin and amelogenin were highly expressed in secretory ameloblasts. The expression of RNA for amelogenin gradually decreased in the post-secretory ameloblasts. In contrast, the RNA expression for amelin remained high in post-secretory ameloblasts up to the stage of fusion between dental and oral epithelia at the time of tooth eruption. We suggest that amelin might be involved in the mineralization of enamel or in the attachment of ameloblasts to the enamel surface. The whole-mount in situ hybridization procedure is described for the first time in dental research. It proved to be a useful method and confirmed the results of the conventional in situ hybridization.
Ameloblasts↗
Osteoclast differentiation.
The osteoclast is the primary bone resorbing cell. It is a highly specialized multinucleated cell whose primary function is to help in the control of calcium homeostasis. The osteoclast has been very difficult to study because of its relative inaccessability, low numbers, and fragility when isolated from bone. Recently, techniques have been developed to study the cell biology of the osteoclast that have expanded our ability to understand the biological and functional properties of osteoclasts. In this article, studies on the origin of the osteoclast are reviewed and the differentiation markers that are used to detect cells in the osteoclast lineage are discussed. Factors that affect osteoclast differentiation are presented and model systems currently in use for studying osteoclast differentiation are evaluated for their relative strengths and weaknesses. In addition, osteoclast differentiation during tooth eruption and root resorption and the effects of bone matrix elements on osteoclast differentiation are reviewed.
Cell Differentiation↗
Essix-based molar distalization appliance.
A new design of molar distalization appliance and its fabrication are described in this article. This case report illustrates distal movement of mandibular molars with negligible loss of anterior anchorage. This new vacuum-formed Essix appliance can be a reasonable alternative to conventional appliances.
Bicuspid↗
The rate of spontaneous closure at the site of extracted mandibular first premolars.
Explore the source record for details and available documents.
Adolescent↗
Pathologically induced molar extrusion--a report of an unexpected odontogenic keratocyst.
The development of a pathological process may occasionally produce unexpected tooth movements, resulting in undesirable effects upon the occlusion. A 14-year-old Caucasian male patient is reported where a mandibular second permanent molar was extruded and tilted by a rapidly developing odontogenic keratocyst, which became evident 1 year after commencing orthodontic fixed appliance therapy. The rapidity of onset, the mode of presentation, and the effects upon the occlusion are discussed.
Adolescent↗
Second molar extraction in the treatment of lower premolar crowding.
Thirty-four children with lower premolar crowding were treated by extraction of second molars. Thirteen cases had mechanical lower arch treatment started not less than 6 months after extractions. The remainder had no treatment in the lower arch. The change in premolar crowding was measured, and the reasons why spontaneous alignment occurred in some cases and not in others were examined.
Adolescent↗
Upper third molars--an unusual position.
Explore the source record for details and available documents.
Maxilla↗