A STUDY ON THE POSITIONAL RELATIONSHIP BETWEEN THE LIPS AND THE TEETH IN KOREAN ADULTS

한국인(韓國人) 성인(成人)의 치아(齒牙)에 대(對)한 구진(口唇)의 위치적(位置的) 연구(硏究)

The prime objective of this study was to analyze the positional relationship of the lips to the anterior teeth according to age, sex, and both sides of the dental arch in 381 healthy Korean adults with normal occlusion ranging from 17 to 70 years over old. The results were as follows; 1. In the position of the corner of the mouth to the teeth, the range from center of canine to mesial side of first premolar was revealed the incidence of 81~87%, the distal side of canine was the hiqhest frequency of 39~43%. 2. A straight type (76~79%) of lip line was prevailed against the curved type in rest position. 3. In the exposed type of anterior teeth to upper lip in rest position, type III(50~52%) Grade 2 (26~29%) was revealed the highest frequency of occurences. 4. No significant difference in both sexes and sides of the dental arch was observed. 5. Lip position to the teeth with aging was showed the tendency toward straight type in lip line and toward reduction of the number of exposed type of upper anterior teeth to upper lip, and the corner of the mouth was placed posteriorly.