Middle and Lower Facial Soft Tissue Changes after Maxillary Advancement through Conventional or High Le Fort I Osteotomy: A Case Series Study

Abstract

Introduction
 Maxillary advancementis applied extensively for malocclusion class III correction.This procedure is done using one of the two methods, Conventional or High.
 Maxilla moves in both vertical and horizontal and only in the horizontal directions in Conventional and High method respectively, so expecting a difference in facialsoft tissue changes. In present study is a case series that describes this issue.
 Materials and Methods: The cases included 30 patients with class III malocclusion due to maxillary deficiency, whom underwent Le Fort I osteotomy for maxillary advancement in Shahid Beheshti Hospital in Babol, Iran during 1995 to 1995. According to surgical technique, the cases were placed in group 1 (Conventional) or group 2 (High). Maxillary advancement and changes in hard and soft tissue of the middle and lower facial regions where measured through tracing on the lateral cephalometry. Intra-group and inter-group statistical comparisons were done using SPSS20 software at significance level as 0.05. Result: The pre-surgical mean size of SNA, SNB, nasolabial and mentolabial angles was similar in two groups. In all patients, after surgery, SNA angle size was increased and SNB، nasolabial and Mentolabial angles size were decreased. The mean value of these change was similar in two groups. In group 2, the displacement of point A ‘(mean difference: 1.30 mm) and Labrale Superius (mean difference: 1.40 mm) were significantly more than group 1. The amount of displacement of SN (mean difference: 1.30 mm), Labrale Inferius (mean difference: 0.88 mm) and Pogonion (mean difference: 0.23 mm) points in group 2 was higher than that of group 1, but this difference was not statistically significant. Conclusion: It is needed strong evidence for decision about selecting High or Conventional approach maxillary advancement in terms of facial aesthetic aspects. So, further studies with larger sample sizes and cohort or quasi-experimental design is suggested