Comparison of the third molar maturity index (I3M) between left and right lower third molars to assess the age of majority: a multi-ethnic study sample

N. Angelakopoulos, I. Galić, S. B. Balla, H. C. Kiş, L. Gómez Jiménez, G. Zolotenkova, M. Y. P. Mohd Yusof, A. Hadzić Selmanagić, H. Pandey, C. Palmela Pereira, J. B. M. Nóbrega, K. Hettiarachchi, S. M. Mieke, A. Kumagai, A. Gulsahi, K. Zelić, N. Marinković, J. Kelmendi, I. Bianchi, I. Soriano VázquezE. Spinas, Y. W. Velezmoro-Montes, I. Oliveira-Santos, Stefano De Luca (Lead / Corresponding author), I. L. Arrais Ribeiro, M. Moukarzel, R. Cameriere

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


The diagnostic accuracy of the I3M to assess the legal age of 18 years has already been tested in several specific-population samples. The left lower third molar has been extensively used for discriminating between minors and adults. This research aimed to compare the usefulness of lower third molar maturity indexes, from both left and right side (I3ML and I3MR), in samples originating from four distinct continents in order to examine possible differences in their accuracy values. For this purpose, a sample of 10,181 orthopantomograms (OPGs), from Europe, Africa, Asia and America, was analysed and previously scored in other studies. The samples included healthy subjects with no systemic disorders with both third molars and clear depicted root apices. Wilcoxon Signed Rank test for left and right asymmetry did not show any significant differences. Data about sensitivity, specificity, predictive values, likelihood ratio and accuracy were pooled together and showed similar results for I3ML and I3MR, respectively. In addition, all these quantities were high when only the I3MR was considered to discriminate between adults and minors. The present referable database was the first to pool third molar measurements using panoramic radiographs of subjects coming from different continents. The results highlighted that both I3ML and I3MR are reliable indicators for assessing the legal age of 18 years old in those jurisdictions where this legal threshold has been set as the age of majority.

Original languageEnglish
Pages (from-to)2423-2436
Number of pages14
JournalInternational Journal of Legal Medicine
Issue number6
Early online date6 Jul 2021
Publication statusPublished - Nov 2021


  • Age of majority
  • Asymmetry
  • Dental age estimation
  • Forensic sciences
  • Population data
  • Third molar maturity index (I)

ASJC Scopus subject areas

  • Pathology and Forensic Medicine


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