Sphenoid bone changes in rapid maxillary expansion assessed with cone-beam computed tomography

OBJECTIVE: Rapid maxillary expansion (RME) is used to expand the maxilla and increase arch perimeter; yet, there are few reports on its effects on the sphenoid bone. With cone-beam computed topography (CBCT), it is possible to visualize sphenoid bone changes. The purpose of this study was to investigate sphenoid bone changes observed in conjunction with RME treatments, using CBCT. METHODS: Sixty patients (34 women and 26 men, aged 11–17 years) underwent RME as part of their orthodontic treatment. Patients were randomly assigned to one of three groups: a tooth-anchored group, a bone-anchored group, or a control group. Initial CBCT scans were performed preceding the RME treatment (T(1)) and again directly after the completion of expansion (T(2)). Statistical analysis included ANOVA, descriptive statistics, and the intraclass correlation coefficient (ICC). RESULTS: The reliability of the landmark location was at least 0.783, and the largest ICC mean measurement error was 2.32 mm. With regard to distances, the largest change was 0.78 mm, which was not statistically significant (p > 0.05). Statistical significance was established in patient groups of the same sex and treatment type for the following distance measurements: right anterior lateral pterygoid plate to the right edge of the hypophyseal fossa (d(2)), anterior distance between the medial pterygoid plates (d(4)), and anterior distance between the left medial and lateral plates (d(8)). CONCLUSIONS: In this study, there were no clinically significant changes in the sphenoid bone due to RME treatments regardless of sex or treatment type.