Three-dimensional assessment of the maxilla after modified surgically assisted rapid expansion: a retrospective study

Abstract

Abstract Purpose This retrospective study aims to assess the three-dimensional dentoskeletal effects and median palatal suture opening pattern in patients undergoing modified surgically assisted maxillary rapid expansion (SARME) without separating the pterygomaxillary suture. Methods Twenty-eight patients who underwent modified SARME between 2009 and 2016 were retrospectively evaluated through cone-beam computed tomography (CBCT). Dental and skeletal measurements were taken at three operative times (before the expansion - T0, at the end of the activation of the Hyrax device - T1, six months after the immobilization of the device - T2). Statistical analyses, including ANOVA and Pearson's correlation coefficient, were performed using SPSS software. Results SARME demonstrated significant transverse maxillary expansion (mean 6.05 mm) with a greater impact on the anterior region. Dental measurements, including canine and molar distances, exhibited significant changes over the operative times. Bone measurements (ANS, PNS) showed small but significant alterations, particularly a slight inferior displacement of ANS during device activation. The width of the nasal floor increased, with a subsequent reduction post-immobilization. The median palatal suture predominantly exhibited Type II (V-shaped) opening. Conclusions The modified SARME showed an increase in the transversal direction and a super-lower skeletal displacement, with the anterior region being more affected than the posterior region, but there was no alteration in the anteroposterior direction of the maxilla. There was also an increase in linear dental measurements and a reduction in angular measurement, with a positive correlation between the amount of posterior bone expansion and molar expansion resulting from the treatment in the analyzed period.