Evaluation of Soft Tissue Projection on Axial Cone Beam Computed Tomography Images After Surgically Assisted Rapid Maxillary Expansion

Objective: Surgically assisted rapid maxillary expansion (SARME) is one of the major treatment objectives in orthodontics. It is very obvious that SARME has non-negligible clinical impacts on the facial soft tissues of patients. This study aimed to investigate the correlation between hard tissue expansion and soft tissue projection after SARME on axial cone beam computed tomography (CBCT). Materials and Methods: Sixteen patients (9 women, 7 men) with a mean age of 22.18 +/- 1.64 years and having a transverse maxillary deficiency were enrolled in this retrospective study. A tooth borne Hyrax maxillary expander was applied to the patients and CBCT images were taken before (T0) and 6 months after (T1) SARME. Soft and hard tissue changes were superimposed and evaluated digitally on presurgical and post-surgical axial CBCT images by using In Vivo Dental Software. Results: The mean value of the hard tissue expansion was 4.50 +/- 1.38 mm for the anterior region and 3.92 +/- 1.31 mm for the posterior region. The difference between these values was not significant (p>0.05). There was no correlation between soft tissue projections (p=0.509; r=0.178) and anterior and posterior hard tissue expansion values (p=0.424; r=0.102) on both sides. Conclusion: There was no correlation between soft tissue projection and hard tissue expansion values after SARME. In addition, the difference between the anterior and posterior hard tissue expansion values was not statistically significant.