Applicability of the third molar maturity index for assessment of age of majority in Eastern China

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.

A quick method of determining the age of 8 years old: Based on the first premolars on Eastern Chinese population

BACKGROUND

Whether an individual is over 8 years old is of great significance in clinical medicine and law. The Demirjian, Willems and Cameriere methods are one of the most widely used methods of dental age estimation, but neither method was suitable in Eastern China. And all of them are time-consuming for clinical work. A new and time-saving method for judging whether an individual is 8 years old is yet to be proposed on Eastern Chinese population.

AIM

The paper proposes a method for judging whether an individual is 8 years old based on the relationship between age and the first premolar maturity index (I_1PM), which is related to the measurement of the open apices of the first premolar.

SUBJECTS & METHODS

It is a retrospective study where orthopantomograms of 748 children (356 female and 392male) aged 5-13 years were collected and analyzed. Linear regression was used to infer the value of I_1PM for eastern China. Furthermore, this method was compared to those based on Demirjian's stages F.

RESULTS AND CONCLUSIONS

A cutoff value of I_1PM = 0.35 was taken. The sensitivity of this test was 90.0% and specificity was 93.3%. Furthermore, the proportion of individuals with a correct classification was 90.9%. The results of the test showed that Demirjian's stage F performance was lightly better than I_1pm < 0.35. However, the sensitivity, specificity, and overall accuracy of both are greater than or equal to 90.0%, and the differences are not very significant.