Status of Mandibular Third Molar Development as Evidence in Legal Age Threshold Cases

Lyle W. Konigsberg, Susan R. Frankenberg, Helen M. Liversidge

Research output: Contribution to journalArticlepeer-review


The completion of the third molar roots has played an important role in ascertaining whether individuals may be at or over a legal threshold of age, often taken as 18 years. This study demonstrates that root apex completion in the third molar is relatively uninformative regarding the threshold of age 18 years in a sample of 1184 males, where mean age-of-attainment of root apex completion for third mandibular molars is about 19.4 years. This paper also considers the legal age threshold problem for cases where the third mandibular molar is not completely formed, and outlines the use of parametric models and Bayes’ factors to evaluate dental evidence in statistically appropriate ways. It attempts to resolve confusion over age-within-stage versus age-of-attainment, likelihood ratios versus other diagnostic tests, and prior odds for a case versus the prior density for an age distribution.

Original languageEnglish (US)
Pages (from-to)680-697
Number of pages18
JournalJournal of Forensic Sciences
Issue number3
StatePublished - May 2019


  • Bayes’ factor
  • Markov Chain Monte Carlo
  • age threshold problem
  • dental age estimates
  • forensic science
  • probit analysis

ASJC Scopus subject areas

  • Genetics
  • Pathology and Forensic Medicine


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