Age estimation from the permanent molar in northeast China by the method of average stage of attrition.

A new method of age estimation using permanent molars, the method of average stage of attrition (ASA), is described. A total of 633 molars, including the first molar (M1) and the second molar (M2) on both jaws, was collected from 57 cadavers and 54 modern dry skulls in northeast China. The attrition condition of the molar crown was analyzed, and a new graduation standard was established. Six linear equations for age estimation were obtained by means of regression analysis. The ASA method gave an estimated age at death from only one molar, either M1 or M2, on either maxilla or mandible. The maximum error of these equations was 4.53 years. The results show that the ASA method can or does reflect the attrition condition of the whole occlusal surface more objectively than some methods using dental wear because the wear degree is estimated by averaging the wear stages of all the cusps rather than of only one or partial cusps.