Is there any difference in the development of mandibular third molars according to the type of impaction: An orthopantomographic study in south Indian children and adolescents.

Development of third molars and their influence on the dental arch is a major concern in clinical dentistry especially, orthodontics and oral surgery. Lately, their position, eruption potential and development has become a subject of interest in forensic practice. The present study was aimed to determine whether if there is any difference in the development of the mandibular third molars according to the impaction type. Orthopantomographs (n = 1112) from 478 males and 634 females between 15 and 22 years old were analysed. In each radiograph, impaction status and the developmental stage of mandibular third molars were determined. Descriptive statistics were performed at developmental stages D to H. For stage G, there was a delay by 0.74 and 0.62 years for mesioangular impaction, 0.89 and 0.33 years for horizontal impaction, 1.43 and 0.9 years for distoangular impaction and 1.74 and 1.1 years for vertical impaction, in males and females. For stage H, delay by 0.17 and 0.74 years, 0.05 and 0.06 years, 0.48 and 1.48 years and 0.62 and 0.62 years, respectively for all impaction variants in both sexes. Mean chronological age of the distoangular and vertically impacted mandibular third molars were higher in certain developmental stages than mesioangular and horizontal impactions. Our findings concluded that distoangular and vertical impaction variants mineralize more slowly than mesioangular and horizontal variants, however these differences were smaller. Therefore, no distinction is required between impaction types for dental age estimation especially in the prediction of the age of majority (18 years).

A test to study the influence of impaction on mandibular third molar development and forensic age estimation in a sample of south Indian children and young adults.

It has been argued that the impaction of the third molars could result in delayed maturation, which, in turn, could affect age estimations in criminal proceedings. In view of this, the present study was undertaken to determine whether the impaction status could delay the chronological process of third molar mineralization in a sample of south Indian children and young adults. The orthopantomograms (OPGs) of 915 children and young adults of south Indian origin aged between 15 and 22 years were evaluated. Mineralisation stage and impaction status were determined for all lower third molars. Descriptive statistics were performed at stages D to H of Demirjian staging system. The results of independent t-test show that the impaction resulted in statistically significant slower mineralization in impacted lower third molars at stages D to F in both sexes. It was ascertained that the mean ages with the impacted lower third molars at stage G were 0.98-1.38 years higher in males and 0.50-0.80 years higher in females than those with non-impacted lower third molars. For stage H, the mean ages were 0.14-0.21 years higher in males and 0.25-0.44 years higher in females. The probabilities of being 18 years and above is higher for non-impacted lower third molars at stages G and H than those with impacted ones. It is concluded that the impaction could result in delayed maturation in the lower third molars of the studied sample. Further studies are warranted in a more diverse sample.

Third molar development in a London population of White British and Black British or other Black ethnicity.

Population differences in dental development between Black and White ethnic groups have been debated but not previously studied in the UK. Using inappropriate data for dental age estimation (DAE) could lead to erroneous results and injustice. Data were collected from dental panoramic radiographs of 5590 subjects aged 6-24 years in a teaching hospital archive. Demirjian stages were determined for left-sided teeth and third molars and data collected regarding hypodontia and third molar agenesis. Third molar development in self-assigned Black British, including other self-assigned Black ethnicity, was compared with that of self-assigned White British subjects. Data were compared for males and females in the two ethnic groups using T-tests for Demirjian Stages A-G of third molar development and Mann-Whitney tests for Stage H once a cut-off age at the maximum age for Stage G had been imposed. Third molar development occurred earlier in subjects of Black ancestry compared to those of White ancestry. While both ethnic groups showed large age ranges for every third molar stage, in female subjects these generally occurred at least 1.5 years earlier, and in males at least one year earlier. Hypodontia and third molar agenesis were more prevalent in White British, but the ethnic difference in third molar development persisted in subjects with complete dentitions. This is a large study that confirms ethnic differences in a London population, emphasises the difficulties of establishing the 18-year-old threshold using DAE, and confirms the risk of overestimating the age of individuals of Black ethnicity using White ethnic reference data.

Mandibular Canine Calcification Stages as an Indicator of Skeletal Maturity.

AIMS: The aim of this study was to verify whether there is significant relationship between stages of mandibular canine calcification and skeletal maturation and to determine whether the same can be used as a reliable diagnostic aid to assess skeletal maturity. MATERIALS AND METHODS: The sample consisted of 50 males and 50 females aged between 8 and 15 years. Two radiographs namely orthopantomograph and handwrist radiograph were taken for this study. Skeletal age was ascertained from handwrist radiographs according to the method introduced by Fishman L.S. The developmental stages of mandibular canine were assessed according to Demirjian's stages of dental calcification. RESULTS: The relationship between canine stage calcification and skeletal maturity index was statistically significant in all stages. INTERPRETATION AND CONCLUSION: Mandibular canine calcification stages can be recommended as a supplemental diagnostic aid. Similar studies may be conducted in different population to rule out any possible racial and regional influences on growth characteristics.