永久歯列の歯槽突起吸収指数を用いての年齢推定 : 大規模災害に備えて

Abstract

There have been numerous medico-legal reports regarding age estimation on the basis of oral cavities, but none on the relationship between alveolar process resorption and age. The author took 600 X-ray photos (males 300, females 300, aged 20-99 years)of each proximal alveolar process except for wisdom teeth. A straight line between the mesial cervical point and the distal cervical point, was made on each photograph. A line of falseness, parallel to the first line and the tooth root apex, was set up. The distance (A) from the cervical line (cement-enamel junction, CEJ), the distance (B) from the deepest point that the alveolar process is absorbing, to the tooth root apex from the falseness line was measured, and the index of the alveolar process resorption for each region was calculated by the following formula : Index of the alveolar process resorption = the deepest point of the alveolar process-root apex distance (B) ×100/CEJ -root apex distance (A). There was a tendency for the index of the alveolar process resorption to decrease with increasing age, and it was found that the index and age were negatively correlative (coefficient of correlation r = -0.909 ～ -0.982, P＜0.001) both in the anterior and posterior groups of both jaws. The following formulae were established : All teeth examined group, Y = -1.84X + 19194 (±4.06 years) ; Upper anterior teeth group, Y = - 2.17X + 222.89 (±4.03 years) ; Upper molar teeth group, Y = -1.82X + 188.41 (±4.56 years); Lower anterior teeth group, Y= -1.60X + 173.49 (±3.48 years) ; Upper molar teeth group, Y= -1.77X + 182.95 (± 4.11 years) where Y = estimated age, and X = the average of the indicies of alveolar process resorption in each group. The age estimation equations showed accuracies of 82.9% or more for the age range of ±5 years, and 99.1% for ±7 years in the all teeth examined group. This accuracy is satisfactory for age estimation in personal identification in large-scale disasters.