Methods: In this retrospective quasi experimental study, 51 patients were evaluated (25 patients had isolated mandibular surgery and 26 patients had simultaneous maxillary impaction and mandibular advancement). Lateral cephalograms were taken immediately before surgery and at one year follow-up. The cephalograms were superimposed on SN and registered on S point. The changes of 47 variables were assessed based on analysis introduced by Solow. The significance of changes in each group and between the groups were demonstrated by paired t-test.
Results: In both jaw surgery groups, mandibular hard and soft tissue landmarks (especially B point, lower Incisal edge and Pogonion), moved superiorly and anteriorly reflecting the upward and forward rotation of the Mandible that occurred as a result of the maxillary impaction. In mandibular advancement group, soft and hard tissue mandibular structures were positioned anteriorly and superiorly. On average, the SN-Pog angle increased 5.0° (SD=3.5°) and the ANB angle decreased 4.0° (SD=1.6°), the mandibular plane to SN angle decreased significantly (P<0.04). No statistically significant difference was observed between the two types of surgery.
Conclusions: The craniofacial changes after maxillary impaction and mandibular advancement surgery were similar to those seen in only mandibular advancement procedure.