Stability of skeletal Class II correction with 2 surgical techniques: the sagittal split ramus osteotomy and the...

Combined orthodontic and surgical treatment of severe Class II dentoskeletal deformities with the use of the bilateral sagittal split ramus osteotomy is a routine procedure in orthodontic practices. However, an alternative surgical technique, the total mandibular subapical alveolar osteotomy, could be used for the same purpose. The aim of this investigation was to compare the stability of the sagittal split ramus osteotomy with the total mandibular subapical alveolar osteotomy in the correction of dentoskeletal Class II malocclusions. Forty patients that exhibited Class II dentoskeletal relationships were included in the study. Twenty of these patients had mandibular advancement with the sagittal split ramus osteotomy; the remaining 20 patients had advancement of the whole lower alveolar segment with the total mandibular subapical alveolar osteotomy. The cephalograms studied were taken before the surgical procedure (T1 = 4 weeks before operation), immediately after the procedure (T2 = 10 days after surgery), and 1 year later (T3). The statistical analysis used to assess the results between and within the groups over the different time periods was the analysis of variance. The regression analysis was used to test the interdependence of soft tissue response to hard tissue movement. The results of this study show that both procedures are equally stable when correcting Class II malocclusions. This was proved by the stability of the correction of overjet, B point, and incisor-mandibular plane angle. There were no statistically significant differences between or within the groups in the position of these landmarks over time. There was a statistically significant change in the position of pogonion from T1 to T2 (P <.0028) between the groups, although at T3 this difference was not significant (P <.05). There were no significant changes in face height either within or between the groups over time. The hard/soft tissue interactions for the total mandibular subapical alveolar osteotomy were as follows: The lower lip advanced 60% to the incisor movement; soft tissue B' point responded with a 130% advancement in relation to the change in its hard tissue counterpart. Soft tissue pogonion advanced 90% in relation to the hard tissue landmark. The data suggest that the total mandibular alveolar osteotomy is the treatment of choice for the correction of severe dentoalveolar retrusive Class II malocclusion for which alteration of the mentolabial sulcus is desirable.