The effects of posterior retraction on the displacement of the maxilla

• 발행기관: 대한치과교정학회
• 저자명: Bo-Yeong Yoo Jong-Chul Kim
• 간행물 정보: 『The Korean Journal of Orthodontics』제26권 제6호, 691~703쪽, 전체 13쪽
• 주제분류: 의약학 > 기타의약학
• 파일형태: PDF
• 발행일자: 1996.12.31

영문 초록

Three-dimensional finite element model was made from adult skull to find desirable direction of retraction force to treat skeletal class II malocclusion. The retraction force of 400g was applied to the first molar. The direction of the force application was 23^° downward, parallel, 23^° upward and 45` upward to the occlusal plane. The stress distribution and the displacement within the maxilla were analyzed by three-dimensional finite element method. The findings obtained were as follows: 1. Maxillary first molar was displaced posteriorly and inferiorly in 23^° downward, parallel, 23^° upward retraction but it was displaced posteriorly and superiorly in 45^° upward retraction. 2. ANS, A point and prosthion were moved posteriorly and inferiorly and pterygornaxillary fissure was moved posteriorly and superiorly. Clockwise rotation of maxilla occurred when retraction force was applied. 3. The degree of clockwise rotation of maxilla was greatest when the force was applied 23^° upward to the occlusal plane and was least when the force was applied 23^° downward to the occlusal plane. 4. Large tensile stress appeared in maxillary first molar and alveolar bone and the infraorbital region of maxilla when the force was applied 23^° downward to the occlusal plane. Tensile stress was smaller as the direction of force move upward. 5. Large compressive stress was appeared in maxillary first molar and infraorbital region in 45^° upward case and large compressive stress occurred in the posterior part of maxilla as the retraction force was upward.

키워드

posterior retraotion maxilla three-dimensional finite element method