A study on positional changes of the teeth and mandible according to fixation type during intermaxillary fixation period after mandibular setback

ABSTRACT

Skeletal relapse is known as a complication following orthognathic surgery of mandibular prognathism and occurring during intermaxillary fixation period. Therefore relapse of teeth and skeleton during intermaxillary fixation period is considered as a important problem of orthognathic surgery. In this study, cephalolateral radiographs taken at pre-operation, immediate post-operation and after release of intermaxillary fixation were measured for evaluation of dental and skeletal relapse in 30 cases. The cases were classified as screw fixation group and plate fixation group, then we compared magnitude of dental and skeletal changes of each group. The results were as follows 1. The 1 SN angle increased at immediate post-operation with a mean value of 0.12 degrees and at intermaxillary fixation period with a mean value of 0.43 degrees (p>0.05). 2. The l .. MP angle decreased with a mean value of 0.14 degrees at immediate post-operation and with a mean value of 1.28 degrees during intermaxillary fixation period but there were not significant difference(p>0.05). 3. There were not significant difference in magnitude of dental position changes between screw fixation group and plate fixation group(p>0.05). 4. Gonial angle increased with a mean value of 0.62 degrees during intermaxillary fixation period. Each group showed changes of gonial angle during intermaxillary fixation period but there were not significant difference(p>0.05).