A Study on the Range of Movement of Mandible in Young Persons

하악의 운동범위에 관한 연구 -20대 청년층을 중심으로 -

Maximal active movements of the mandible in the vertical and the horizontal plane were measured in 106 mem and 78 women. ranging from 20 to 29 years old, with a method devised by agerberg. The studied persons who were dental students of the School of Dentistry Seoul National University (SNU), nurses and dental auxiliaries of the SNU Hospital, had no pain or severe symptoms of dysfunction of the masticatory system. The obtained results were as follows : 1. The mean values for maximal opening and protrusion differed significantly between men and women, 55.9 mm and 49.7 mm, 9.3 mm and 7.4 mm respectively. 2. The means found for maximal lateral movement to the right and to the left were practically the same, 8.5 - 9 mm and did not differ with sex. 3. The lower limit of the normal range of horizontal movements may be regarded as 4 mm for men and 3 mm for women and maximal opening as 44 mm for men and 39 mm for women. 4. The maximal mandibular movement ranges of 20-year old person with 95 % probability were calculated and presented grphically.