Advantages and limits of 3-segment (paramedian) versus 2-segment (median) surgically assisted rapid maxillary expansion (SARME)

Background. A novel maxillary 3-segment osteotomy (3SO) was evaluated versus the conventional 2-segment-osteotomy (2SO) for surgically assisted rapid maxillary expansion. 3SO was performed bilaterally between the lateral incisors and canines at the former junction of the lateral alveolar processes with the premaxilla. Study design. Of 98 included patients (n = 53 retrospectively and n = 45 prospectively; 68 complete datasets), 47 patients' preoperative and postexpansion cast models were evaluated for transverse maxillary dental and skeletal expansion, dental tipping, attachment loss, and front teeth angulation, and on photographs the pink esthetic score (PES) was assessed preoperatively versus postoperatively. Results. Three-SO expanded to a larger extent with more symmetry than 2SO, at the price of more dental tipping and front teeth angulation (independent t test). The PES showed better esthetic outcomes for 3SO (Mann-Whitney U test). Conclusions. Disadvantages of 2SO, such as median diastema, midline shift, median papilla infringement, asymmetric expansion, septum and columella dislocation, high forces on the periodontal apparatus, and subsequent attachment loss were overcome with 3SO. Bilateral double osteotomies appeared to promote higher volumes of callus formation, thus preventing relapses. (Oral Surg Oral Med Oral Pathol Oral Radiol 2012;113:29-40)