Effects of Surgical and Nonsurgical Rapid Maxillary Expansion on Palatal Structures.

Aim: The aim of the present study was to compare the effects of surgical and nonsurgical rapid maxillary expansion (RME) in skeletally mature patients.

Materials And Methods: Surgically assisted rapid maxillary expansion (SARME) was used in 18 patients (2 males, 16 females) with a mean age of 19.90 years. Two nonsurgical RME groups were constructed to compare the expansion changes of SARME. Eighteen patients in maximum pubertal peak (12 males, 6 females) with a mean age of 13.04 years comprised the growing RME group, while the nongrowing RME (NG-RME) group consisted of 18 skeletally mature patients (1 male, 17 females) with a mean age of 16.41 years. Thirteen linear and 2 angular measurements were made on the study models taken before expansion (T0) and after 3 months of retention period (T1). Intragroup differences were evaluated with paired t test and the intergroup differences were analyzed with 1-way analysis of variance.

Results: All groups showed significant transversal skeletal and dental expansion. The palatal width changes at gingival and midpalate levels were the highest in the NG-RME group (6.85 and 5.84 mm, respectively). The most molar tipping was in the NG-RME group (15.00°) and the palatal vault angle showed the most increase in the SARME group (9.77°). The greatest expansion at the base of palatal vault was in the SARME group (4.42 mm).

Conclusions: The pattern of expansion was rotation of the maxillary halves for SARME and lateral displacement of the dentoalveolar structures for NG-RME. Patients with severe skeletal discrepancy or increased age are good candidates for SARME.