This study is proposed to analyze statistically the causes of extraction of permanent teeth among outpatients who visited our dental department of Sung-Sim Hospital, Chung-Ang University from Jan. 29th 1979 to Nov. 30th 1980. the results are as follows. 1. The group of patients aged 25-34 had more number of extracted teeth than any other age group. 2. It was found that woman's (0.13) was more than man's(0.9) in average number of extracted teeth per patient. 3. In analyzing the causes of extraction, it was identified as caries 37.5%, periodontal diseases 27.2%, wisdom teeth 17.6%, for orthodontic treatment and impacted supernumerary teeth and others 8.0% trauma and fracture 4.2%. 4. The primary cause of extraction was found to be changed from caries to periodontal diseases according to the increase of age. 5. The number of teeth that were extracted by trauma was found that man's (38) was more than twice as much as woman's (17) and the group of patients aged 35-44 had the most number of all age groups.

This study was undertaken to find out the characteristic craniofacial morphology of Class II Division 2 malocclusions in children by means of roentgenocephalometry. The subjects consisted of twelve boys and thirteen girls with Class Ii, Division 2, thirty seven boys and fifty three girls with Class II, Division 1, and forty six boys and eighty one girls with normal occlusion, ranged from 10 years old to 18 years old. The following results were obtained; 1. The anteroposterior relationship of the maxilla to the cranium in the Class II, Division 2 malocclusion similar to the normal occlusion, but the mandible was the posterior position in th the cranial anatomy. 2. There were no significant differences in the anteroposterior relationship of the maxilla and the mandible between Class II, Division 1 and Class II, Division 2 malocclusions. 3. In Class II, Division 1 the axes of maxillary incisors showed labial inclination, but lingual inclination in Class II, Division 2 malocclusions. 4. Overbite was prominent one in Class II, Division 2, on the other hand overjet was distinguished in Class II, Division 1.

치과임상에 있어서 약제, 재료, 기구 및 기타 부대시설과 치료실 환경은 오랫동안에 걸쳐 현금에 와서 놀라운 발전을 이룩하였음에도 치과의사가 시술중 받게되는 위해의 가능서은 아직도 여러곳에 상존하고 있는 실정이다. 의사가 늘 갖고 또 자신이 느껴야 되는 책임감에서 오는 긴장, 기계에서 오는 소음이 미치는 신체적영향 특히 청력과 관계되는 점 및 각종약제의 부작용 및 중독증, 그리고 치료중 예기치 않게 발생될 수 있는 환자로 부터오는 각종 감염, 도한 치과의사의 특수한 치료자세로부터 생기는 습관적인 정형외과적 문제와 정신적 육체적으로 겪게되는 격무로부터 오는 전신피로등의 문제를 어쩔수 없이 또는 치과의사 자신의 부주의로 당하고 있는 실례가 많다. 저자는 이 점에 대하여 위해가 생기는 문제를 항목별로 기술하면서 문헌적 고찰과 말레이시아의 치과의사 164명으로부터 설문을 통하여 수집한 사실의 통계를 분류하여 정리하고 그 예방 및 개선의 방법을 제시하면서 이는 치과의사뿐 아니라 종사자 전원이 숙지하여야 할 사실로 강조하였으며 가장 이상적인 치료실내의 치과의사용 의자를 고안하고 그 구조에 대하여 설명 하였다.