두부방사선(頭部放射線) 계측법(計測法)에 의(依)한 Hellman 치령(齒齡) III A 정상교합(正常咬合) 아동(兒童)에 관(關)한 연구(硏究)

This study was undertaken to estabish the cephalometric standards of Hellman dental age III A group of Korean on the roentgenocephalometry. The subjects consisted of 26 males and 29 females with the normal occlusion and acceptable profile. The following conclusions were obtained; 1) The tables of mean and standard deviation were made from the measurements of both male and female. 2) A ll linear measurements in male were greater than those in female. 3) Mandibular growth rate of female was greater than that of male. 4) Comparision of the childern in Hellman dental age III A with those in the late primary dentition indicated the tendency of facial vertical growth.