Background: Maxillary expansion in skeletally mature patients with fused mid palatal suture and circum maxillary resistance makes the conventional non-surgical expansion methods insufficient. Aim: To evaluate the dentoalveolar changes occurring with corticotomy assisted SME. Methods: Sixteen patients (4 males and 12 females) requiring maxillary expansion (mean age:19 years; range: 14-24 years) were divided into two groups: Group A: included 10 patients subjected to buccal alveolar corticotomy before SME and Group B: included 6 patients who had only SME.CBCT images were taken at T1(before) and T2 (after). Inter molar (IMW) and Inter premolar widths (IPmW) as well as root angulations (RA) and buccal bone thickness (BBT) at the level of first molars and first premolars were recorded. T-tests (paired, student) determined the significance (P90.05) performed to evaluate the effect of treatment within and between each group. Results: Expansion achieved in corticotomy group was 5.900±0.348mm for IMW and 5.000±0.258mm for IPmW, and was significantly higher than SME only group. Root tipping showed no statistical significant differences between both groups. Buccal bone thickness decreased significantly in both groups with no statistical significant differences between both groups. Conclusions: Corticotomy assisted expansion is an efficient and safe treatment and shows a significant increase in IMW and IPmW compared to SME only. Non-significant differences in root angulations between the two groups were noted suggesting that the expansion in corticotomy group was more translatory movement than tipping. The corticotomy procedure does not cause a different response of buccal bone compared to SME only group.