Bone Density of the Midpalatal Suture After Surgically Assisted Rapid Maxillary Expansion: A Retrospective Cohort Study

Abstract

Objectives: To evaluate the bone density in the midpalatal suture after 10 months of surgically assisted rapid maxillary expansion (SARME) with the separation of the maxilla into 2 segments. Methods: Sixty multislice computed tomography (MCT) from 20 patients undergoing SARME were analyzed in 3 periods of time (1 MCT per patient on each occasion): (1) 1 week before surgery, (2) postsurgery immediately after completing the expander activation, and (3) 10 months after the expander activation. On all occasions, the bone density was measured in Hounsfield units on MCT scans in axial and coronal sections, in the anterior (A1), middle (A2), and posterior (A3) regions of the midpalatal suture. Results: The mean percentage values of bone density in Hounsfield units, from the 10-month postactivation period to preoperative in the A1, A2, and A3 regions were 68.38%, 38.21%, and 55.90%, respectively, in the axial norm, and 64.06%, 36.81%, and 55.50% in coronal norm (A1 = A3>A2), with no significant difference in the tomographic cuts (P >0.05). There was no correlation between patient age or amount of expansion in the expander and bone density. Conclusions: The bone density in the midpalatal suture 10 months after SARME is lower than preexpansion. A denser new bone formation along the suture concentrates closer to the extremities rather than in the central region. Although the maturation of the new bone formation in the midpalatal suture is lower 10 months after SARME, it appears to be sufficient for satisfactory clinical results, regardless of patient age or the amount of expansion in the expander.