Which Works Best for Adult Maxillary Expansion? A Retrospective CBCT Comparison of Three Orthodontic Techniques

Objective: To compare the skeletal, alveolar and dental effects of three maxillary expansion modalities, Rapid Maxillary Expansion (RME), Miniscrew-Assisted Rapid Palatal Expansion (MARPE), and Surgically Assisted Rapid Maxillary Expansion (SARME) in skeletally mature patients using standardized cone-beam computed tomography (CBCT).Materials and Methods: This retrospective comparative study included 43 adults (≥18 years) diagnosed with transverse maxillary deficiency and treated between 2015 and 2024.Patients were divided into four groups: RME with a Haas expander (Group A; n=8), MARPE with a bone-anchored MSE (Group B; n=18), SARME with a tooth-borne Hyrax (Group C1; n=9), and SARME with a bone-borne distractor (Group C2; n=8). Pre- and post-expansion CBCT scans were obtained. Skeletal, alveolar, and dental measurements, including sutural expansion, buccal and palatal cortical widths, alveolar tipping, and intercuspal width at the first molar, were recorded using InVivo software. All measurements were performed twice by two blinded, calibrated examiners. Statistical analysis included paired t-tests, one-way ANOVA, and Bonferroni post-hoc tests .Results: All modalities produced statistically significant pre-to-post increases (p < 0.05). Group A showed the least skeletal sutural expansion compared with Groups B, C1, and C2 (p < 0.01). MARPE and both SARME groups demonstrated greater skeletal and alveolar widening with markedly less alveolar tipping. Intercuspal width increased significantly in all groups, with Group A exhibiting the smallest dental change. Conclusion: MARPE and SARME provide superior skeletal expansion compared with tooth-borne RME in skeletally mature patients. These findings offer evidence based guidance for selecting the optimal expansion modality in adults.