A Comparison of pre and post-surgical characteristics in skeletal Class III malocclusion patients using counterpart analysis

Sohn, Byung Wha; Kyung, Seung Hyun; Kim, Beom soo

Abstract

Enlow's counterpart analysis explains the complex with anatomic and developmental characteristics where craniofacial aspect of individuals has been developed. Counterpart analysis does not compare individual measurement with the normal value from the average of majority but analyzes by comparison of values that each individual has. In this study we examined surgical changes in skeletal Class III malocclusion patients(male 40, female 40) and compared them with normal occlusion patients using counterpart analysis. The results indicated that : 1. Skeletal anterior-posterior discrepancy was relieved by shortening of the ramus width(B3). 2. The ramus alignment(R3, R4) was displaced posteriorly and the occlusal plane angle(R5) was rotated clockwise. 3. Skeletal Class III pattern was relieved in the post-operative group, but differences in the level of the cranium(R1, R2) was remaining compared to the normal occlusion patients. 4. In the comparison of surgery methods, the two-jaw surgery group presented changes in the maxillary length(A4), ramus alignment(R3,R4) and occlusal plane angle(R5) compared to the one-jaw surgery group, but the differences were not significant. In the past study about Korean skeletal Class III patients, the skeletal characteristics are upward backward rotation of the cranial base, posterior displacement of the maxilla, forward inclination of the ramus and lengthening of the mandibular body, but in this study, skeletal Class III pattern was relieved by shortening of the ramus width and maxillary advancement by orthognathic surgery, because orthognathic surgery is usually performed on limited areas in the maxilla and the mandible.