Mature Dentition Research Articles

Body mass index in relation to dental maturation of 10 to 14 years old school children in Erbil city. A cross-sectional prospective study.

Background and Objectives: Estimation of dental age is based upon the rate of development and calcification of tooth buds and their progressive sequence of eruption in the oral cavity. The tooth calcification provides a valuable indicator of dental age and serves as an index of the maturation of the child. The aim of this study is to determine whether Body Mass Index (BMI) has association with dental maturation. Materials and Methods: A cross sectional study design was applied for the present study, 383 school children were participated in this study which nominated from Erbil city. For the sample to be representative the city was divided in to six geographic areas according to the municipalities, the samples randomly selected school children of 10 to 14 years old from both genders. The height and the weight of each participant had been recorded in the college of dentistry / Hawler Medical University in order to calculate the body mass index of the following the guidelines of centers of disease control (CDC) , at the same time an orthopantomography radiograph had been used to investigate the stage of the dental maturation using the Demirjian method, finally, the relationship between BMI and dental maturation were investigated using chi square test with P value of ≤ 0.05 was considered significant difference. Result: there was a statistically significant relationship between dental maturation and BMI. The majority (93.6%) of samples with under-mature dentition were under-weight at the same time. The vast majority (96%) of samples with mature dentition had normal BMI. In the same manner, majority (91.7%) of samples with over mature dentition were over-weight too. Chi square test was used to find out the association and P-value was 0.001 Conclusion: In conclusion, normal weight students have normal dental maturation, underweight students have under dental maturation and overweight or obese students have over dental maturation. Keywords: body mass index, Demirjian, Orthopantomography.

Secular trend in the maturation of permanent teeth in a sample of Turkish children over the past 30 years

This study was performed to evaluate the influence of secular trends on dental maturation among Turkish children over the past 30 years.Orthopantomograms of 757 (385 boys, 372 girls) Turkish children born in the 1980s, 1990s, and 2000s were evaluated. Three groups were formed based on decade with five subgroups by age from 9 to 13 years old for each gender. The number of samples in each age group and gender were matched. The mandibular left seven permanent teeth were evaluated based on formation stage to determine the overall dental maturity score. The groups were compared based on decade and gender. The Bonferroni-corrected Mann–Whitney U test and Kruskal–Wallis tests were used for statistical evaluation.Among 11-, 12-, and 13-year-olds born in the 2000s, girls exhibited significantly more mature dentition than did boys (p<0.01, p<0.05, and p<0.05, respectively). Twelve-year-old girls born in the 1990s and 2000s exhibited significantly more mature dentition than did girls born in the 1980s (p<0.01).Girls generally exhibited more mature dentition than boys. No significant positive secular trends in dental maturity were observed from the 1980s through the 2000s. Dental maturation among Turkish children was not affected by a secular trend.

Influences in a biologically complex adaptive system: Environmental stress affects dental development in a group of Romano-Britons

The human dentition shows the general characteristics of a complex adaptive system. Interactions at a molecular level of genetic, epigenetic and environmental factors lead to the emergence of tooth germs. Subsequently differentiated specialised cells control mineralisation and then mature teeth emerge, showing marked variation. The mature dentition provides a record of developmental influences from its initiation at 6 weeks in utero to its completion at 20 years of age. It is, therefore, a valuable paradigm of general development. The substantial collection of skeletal material of 200–400 AD Romano-Britons from Poundbury, Dorset, has been extensively studied, providing much evidence concerning lifestyle and medical conditions. In this study, we investigate further findings concerning dental development. The aims are to compare the findings with those for Modern Britons and to identify the effects of major factors known to affect the Romano-Britons in order to consider the possible synergism of these effects. The findings were that the patterning of the dentition, its sexual dimorphism and the types of developmental defects were similar to modern Britons. However, the RomanoBritons had more anomalies, generally smaller tooth crowns and roots, and more severe enamel defects. Thus, the Romano-Britons’ dentition showed evidence of insults occurring at all stages of tooth development. These effects, occurring over a long period of time and affecting tissues with different genetic backgrounds, probably arise from ongoing major environmental insults known to be present in Poundbury. These insults have been identified as excess lead ingestion, poor nutrition and recurrent infections. We propose that these factors, acting synergistically, constituted marked environmental stress affecting development.

Occlusal plane related to skeletal pattern in mixed dentition stage: a descriptive cephalometric study

Basic studies and researches on craniofacial growth show that occlusal plane changes its position in space and time during the whole period of development and growth of the skull until the attainment of the mature dentition stage. The purpose of this retrospective study is to evaluate the inclination of the gnatological occlusal plane related to the axio-orbital plane and their relations with skeletal pattern in a group of subjects during the period of mixed dentition stage. This is performed analyzing cephalometric tracings of 714 untreated children between 5.6 and 12 years old. Observations of data indicate that there is difference in inclination between skeletal class I, class II and class III, being more steep in class II and more flat in class III. Variations between the subclasses demonstrate very high degree of individuality of the inclination of the occlusal plane related to the functional axio-orbital plane in subjects in mixed dentition stage.

Difficulties in estimating age using root dentine translucency in human teeth of varying antiquity

Estimation of age at death is an essential part of reconstructing information from skeletal material. This becomes more difficult after development has ceased and following taphonomic alteration in archaeological material. Most biological markers of age do not record the chronological age (calendar age), but the biological or physiological age of the individual. Of the age-related changes in the mature dentition of modern samples, the extent of root dentine translucency (RDT) has been shown to correlate closely with chronological age. A protocol for measurement of RDT was established and applied to modern and archaeological teeth of known age (Spitalfields sample). Percentage length of RDT in sectioned teeth was found to correlate well with chronological age in the modern sample but not in the archaeological sample. The majority of the archaeological sample was affected by a morphological change creating a “chalky” appearance to the dentine. Removal of the obviously affected teeth did not improve the correlation coefficients to any useful degree. “Chalky” dentine appeared, under the light microscope, to be composed of large fenestrations, islands of mineralized tissue and masses of filiform structures that appeared to be following the path of the dentinal tubules in their invasion of the peripheral dentine. The filiform structures are consistent in their appearance with a previously reported tunnelling mycelium and impart such an effect on RDT that it cannot readily be used for age estimation in affected teeth.

Effects of actinomycin D on developing hamster molar tooth germs in vitro.

The aim of this study was to evaluate the toxic effects of actinomycin D on the developing hamster tooth germ in organ culture. Hamster tooth germs during early secretory amelogenesis were exposed in vitro for 24 h to 10(-9) M-5 x 10(-5) M actinomycin D. Actinomycin D dose-dependently (> or = 10(-7) M) decreased the tooth germ dry weight but mineralization was affected only by doses > or = 10(-5) M. However, the uptakes of TCA-insoluble 32P and [3H]thymidine were significantly reduced dose-dependently from > or = 10(-8) M actinomycin D, indicating that the drug inhibits the synthesis of phosphate-containing macromolecules as well as DNA synthesis. Histologically, 10(-8) M actinomycin D was the lowest dose which was not toxic to any cell type in the developing tooth germ. At 10(-7) M actinomycin D, the most sensitive cells were the proliferating pre-odontoblasts followed by pre-ameloblasts; the mature secretory ameloblasts and odontoblasts appeared unaffected. Higher doses resulted in increased cytotoxicity to the secretory cells and, eventually, total degeneration of most cells. The data suggest that children treated for cancer during tooth development using anti-chemotherapy cocktails containing actinomycin D (serum levels > 10(-7) M) may develop defects later on in the mature dentition as a direct consequence of the toxicity of the drug to the tooth organ.

Developmental Changes in Alignment of the Lower Labial Segment

The purpose of this study was to examine changes in lower incisor alignment at various developmental stages, from the time of eruption to the established permanent dentition and to try to predict the degree of crowding in the permanent dentition from that observed at earlier developmental stages. Forty-eight subjects (20 male, 28 female) with intact mandibular arches were selected from the Belfast growth study records. The lower incisor space condition was measured at each of four developmental stages: (1) initial eruption of the lower permanent incisors; (2) initial eruption of the permanent canines; (3) initial eruption of the second molars; (4) 3 years after eruption of the second molars. Differences in lower incisor space condition between each developmental stage were investigated and correlation analyses between the space conditions at each stage were carried out. On average, crowding of the lower incisors decreased to a statistically significant degree (- 0.9 mm) between stages 1 and 2, and increased between stages 3 and 4 (0.4 mm). Significant correlation coefficients between space condition at each developmental stage were found, but were considered unreliable as predictors of lower incisor crowding in the mature dentition.

Tooth Enamel Thickness in the Mature Dentition of Domestic Dogs and Cats - Preliminary Study

The thickness of the enamel of dogs and cats was measured in 194 teeth. The enamel was found to be thinner than that of human teeth, varying in thickness from 0.1mm-1mm. The "enamel bulge" coronal to the cemento-enamel junction does not consist of a thickened area of enamel.

Variation in Foraging Behaviour in Red Deer and the Consequences for Population Demography

(1) Individual differences in the predicted foraging efficiency of forest-dwelling red deer Cervus elaphus L. are used to assess the consequences for population demography. (2) Analysis of the ontogeny of the incisor arcade and its allometry with body weight shows that growing animals experience restricted incisor breadth relative to weight during the transition from juvenile to mature dentition. (3) A model of bite dimensions predicts that yearlings, male calves and stags will have the greatest reduction in foraging efficiency when feeding on depleted resources. This is corroborated by observed patterns of seasonal weight loss. (4) Sex differences in growth strategy combined with the ontogeny and allometry of the incisor arcade may cause differential mortality between age and sex classes. It is suggested that population ecology and life-history theory should take greater account of natural selection on the juvenile phase.

On the Dichodon cuspidatus , Owen

In June 1847 I communicated to the Geological Society of London a description of certain teeth and portions of jaws of an extinct Artiodactyle Mammal, from the Upper Eocene sand of Hordwell, Hants, from which were deduced the dental characters of the genus Dichodon and of the species cuspidatus . The parts described were of an immature individual, retaining, probably, the deciduous molars; and having, certainly, acquired, in the upper jaw, only the first and second true molars, and in the lower jaw only the first true molar. The second true molar in that jaw was just beginning to appear above the alveolar border; the crown of the third true molar was calcified in the upper jaw, but not in the lower one,—not sufficiently, at least, to give the true form of its crown. I have since been favoured, by the experienced and indefatigable palæontologist. Dr. Wright, of Cheltenham, with the opportunity of examining and describing an instructive portion of the right ramus of the lower jaw of the Dichodon cuspidatus containing the three permanent molar teeth, in situ , and thus supplying the tooth, m 3, which was wanting to complete that part of the mature dentition of the genus. This specimen was found by Dr. Wright near Alum Point, Isle of Wight, in a bed of greenish tough tenacious clay, No. 35 of his Section, which he regards as the equivalent of the Hordwell beds from which Mr. Pytts Falconer obtained the original fossils described by me.