The A.B.F.O. Study of Third Molar Development and Its Use as an Estimator of Chronological Age

TLDR

Radiographs of third molars are used to estimate age, yet their accuracy is uncertain, and because the M3 is highly variable, it is often the sole available indicator for age assessment. The study aims to establish age benchmarks for American white individuals aged 14–24 using 823 forensic odontologist cases. Age benchmarks were derived from 823 cases and summarized by mean and median ages of M3 formation using Demirjian’s eight‑grade classification. Findings show maxillary M3s develop slightly earlier than mandibular ones, root formation occurs earlier in males, and regression formulas with empirical probabilities are offered to determine if a person is at least 18 years old.

Abstract

Abstract Radiographs depicting third molars (M3s) have been used to estimate chronological age in juvenile and adult suspects, but accuracy of the method has been in question. This study provides age benchmarks for American whites (age range: 14 to 24 years) based on cases (n = 823) drawn from diplomates of the American Board of Forensic Odontologists in the United States and Canada. Maxillary M3 formation was slightly advanced over mandibular M3s, and root formation occurred earlier in males than females. Mean and median ages for M3 formation are tabled using Demirjian's eight-grade classification. Regression formulas and empirical probabilities are provided relative to the medicolegal question of whether an individual is at least 18 years of age. The M3 is the most variable tooth in the dentition, but situations arise where M3 formation is the only usable datum for age estimation.