Evaluating the Effectiveness of the Third Molar Maturity Index (I3m) and Mandibular Condyle Cortication for Determining the Legal Age (18) of Latvian Individuals

<b>Background</b>: It is important to accurately determine the legal age at which a person is considered and treated as an adult; in many countries, it is 18. With the increasing migration flow to European countries, accurate age estimation methods must be implemented. In this study, the third molar maturity (I_3m) index and mandible condyle cortication stage were tested to distinguish adult from non-adult Latvian individuals using dental panoramic radiographs. <b>Methods</b>: This study included 716 selected dental panoramic radiographs of patients between the ages of 14 and 22. The lower-left third molar apical root parts were analyzed, and the I_3m index was calculated. In addition, the condyle cortication stage was evaluated. <b>Results</b>: All logistic regression models achieved statistically significant results (<i>p</i> < 0.001). The accuracy was high for all groups (males: 0.90, females: 0.87, both genders: 0.89), and the sensitivity was lower than the specificity, particularly for females (sensitivity: 0.55). The I_3m index appears to be a strong predictor across all models, while the mandibular condyle cortication stage plays a more nuanced role, depending on sex and the stage of condyle maturation. A higher I_3m index value (greater than the cut-off of 0.095 in males) indicates a higher likelihood of being classified as a non-adult male for this model; however, in females, a cut-off point higher than 0.150 indicated a higher likelihood of being classified as a non-adult female. The new proposed cut-off values need to be tested on a new sample. <b>Conclusions</b>: The I_3m index is a reliable age estimation tool, and a modified cut-off value could be determined for each gender in Latvian individuals. The condyle cortication stage is a weak tool for chronological age estimation in dental panoramic radiographs.