ABSTRACT
The purpose of this study is to evaluate hard and soft tissue changes following the first four premolar extractions and anterior subapical osteotomy in bimaxillary dentoalveolar protrusion patients requiring maximal retraction of anterior segments. A sample of 20 adult female patients was selected. Surgical procedures were performed by the same surgeon, and modified segmental osteotomy and anterior subapical osteotomy techniques were employed on the maxilla and mandible respectively. Presurgical and post-surgical lateral cephalometric radiograms were traced and superimposed using the best-fit method and two reference planes. The results were as follows 1. The bodily movement of the maxillary anterior segment was achieved in a posterior direction. The mandibular anterior segment was moved posteriorly with a slight correction of the lower incisors. 2. The horizontal soft tissue measurements changed significantly after treatment, but Nt and Sn landmarks remained unchanged. The vertical soft tissue measurements indicated that Ls moved inferiorly and Li superiorly. 3. The correlation between hard and soft tissue changes indicated that deltaHId/deltaHLi, deltaHId/deltaLL-Eline, deltaHPt.B/deltaHILS, and deltaUI-FH/deltaNL were significant. 4. More lower lip relative to upper lip retraction was demonstrated in relation to Rickett's E-line. The ratio between upper incisor and upper lip displacement was 50%, and between the lower incisor and lower lip displacement was 60%. We conclude from the results that the anterior subapical osteotomy is an efficient treatment option for adult patients who have severe dentoalveolar protrusion and desire rapid results.