Third-molar agenesis shifts mandibular second-molar mineralisation timeline: An orthopantomographic study in South Indian children

Abstract

Background and objective

In many jurisdictions, the 14-year threshold is a legally significant factor in determining criminal responsibility and related decisions. We investigated whether third-molar agenesis is associated with differences in the mineralisation stage of the mandibular second molar in South Indian children.

Design

Orthopantomograms from 570 children (240 males, 330 females; 10–14.99 years) were staged using Demirjian A to H criteria. Descriptive comparisons were supplemented with a proportional-odds ordinal logistic regression, modelling second-molar stage as the ordered outcome, with agenesis extent, age, and sex as predictors. Results are reported as adjusted odds ratios (aORs).

Results

Each additional year of age was associated with substantially higher odds of being in a more advanced second-molar stage (aOR 5.41, 95 % CI 4.47–6.56). Males had lower odds than females of being in a higher stage (aOR 0.58, 95 % CI 0.41–0.81). Relative to children with no third-molar agenesis, the odds of being in a higher second-molar stage were progressively lower with greater agenesis: one missing (aOR 0.53, 95 % CI 0.31–0.91), two missing (aOR 0.39, 95 % CI 0.24–0.62), three missing (aOR 0.26, 95 % CI 0.11–0.62), and all four missing (aOR 0.04, 95 % CI 0.02–0.09).

Conclusion

Third-molar agenesis was associated with less advanced mandibular second-molar stages after accounting for age and sex. Agenesis status and extent may be relevant for the 14-year threshold. Future work should develop and externally validate prediction models that integrate third molar agenesis to improve accuracy and minimise misclassification.