[Surgically assisted rapid maxillary expansion. An evaluation of different surgical techniques and their effect on maxillary dentoskeletal complex based on cone-beam computed tomography. Preliminary report].

AIM: To evaluate and compare the dentoskeletal effects associated with surgically assisted rapid maxillary expansion (SARME) performed with (+) and without (-) pterygomaxillary disjunction (PD), utilizing cone beam computed tomography (CBCT). MATERIALS AND METHODS: A retrospective study of 9 patients (1 male, 8 females, mean age 18.9 years) undergoing SARME who were divided into two groups. In group (-PD) the surgical technique followed involved bilateral LeFort I type of osteotomy plus midline osteotomy. In group (+PD) same protocol was followed and pterygoid disjunction was performed additionally. Three-dimensional CBCT scans were obtained preoperatively and 3-6 month postretention. A Hyrax type acrylic bonded expander was used. MIMICS 14.0 (Materialise Europe, Belgium) software was used to evaluate transverse expansion at skeletal, dentoalveolar and dental level. Additionally dental inclinations, alveolar bending and the pattern of expansion sagittally were assessed. Wilcoxon's and Mann Whitney U tests were used for comparisons. RESULTS AND DISCUSSION: All linear transverse measurements at dental and dentoalveolar level were found to have a statistically significant increase (P < 0.05) in both treatment groups. No statistically significant differences were found between the two groups as well as within groups on skeletal level (except of the anterior expansion of maxilla between piriform rims bilaterally). In -PD group significant buccal tipping of the 1(st) premolar was observed as well as increased buccal bending of the alveolar crest. CONCLUSION: This study confirms that SARME is an effective treatment of maxillary transverse deficiency. CBCT is an adequate tool to assess dentoskeletal treatment effects.