Dental and Skeletal Effects of Two-Piece and Three-Piece Surgically Assisted Rapid Maxillary Expansion With Complete Mobilization: A Retrospective Cohort Study

PurposeThe aim of this study was to examine the dental and skeletal widening effects of 2 surgically assisted rapid maxillary expansion (SARME) techniques after complete mobilization of the maxilla in patients with transverse maxillary hypoplasia and bilateral crossbite.Materials and MethodsA retrospective cohort study design was implemented evaluating 2 treatment groups with complete Le Fort I osteotomy and segmentation of the maxilla followed by distraction using a tooth-borne expansion device: patients without crowding of the incisor roots underwent 2-piece SARME and patients with crowding underwent 3-piece SARME. Linear transverse measurements were performed on dental casts (intercanine and inter-second molar distance) and posteroanterior cephalograms (skeletal jugulum distance) before surgery (T1) and at 6 weeks (T2), 6 months (T3), and 12 months (T4) postoperatively.ResultsThe study included 24 patients (13 women and 11 men; mean age, 27 yr; standard deviation, 18.5 yr). Significant maxillary expansion was achieved by the 2 surgical techniques (P < .05), especially in the posterior portion. From T1 to T2, widening values (+3.8 mm) at the intercanine level in the 2-piece SARME group were significantly higher (P = .004) than those in the 3-piece SARME group. Distraction effects were mainly skeletal, whereas dental relapse tendencies predominated at T3 and T4.ConclusionThe 2 SARME methods ensured sufficient widening with satisfactory results after a 12-month period. To decrease surgical risks to the incisor roots and esthetic impairments, 3-piece SARME with complete mobilization is recommended in cases of transverse posterior maxillary hypoplasia and crowding of the incisor roots.