Comparison of Bipartite Versus Tripartite Osteotomy for Maxillary Transversal Expansion Using 3-Dimensional Preoperative and Postexpansion Computed Tomography Data

Tripartite paramedian osteotomy allowed greater overall symmetric expansion compared with bipartite median osteotomy, with, however, a decline in transverse widening to the posterior. Bipartite osteotomy should be preferred whenever good periodontal status permits greater vestibular bone loss and a midline diastema and asymmetric expansion and a midline shift will be tolerated by the patient. Tripartite osteotomy should be chosen whenever a midline diastema and shift, septal and columellar dislocation, asymmetric expansion, and larger distraction forces on the paradontia, resulting in vestibular attachment loss, are to be avoided.