Analysis of the dentoalveolar effects of slow and rapid maxillary expansion in complete bilateral cleft lip and palate patients: a randomized clinical trial.
The purpose of this study was to compare the dentoalveolar effects of slow (SME) and rapid (RME) maxillary expansions in patients with complete bilateral cleft lip and palate (BCLP). A sample of 50 patients with BCLP and maxillary arch constriction was randomly and equally allocated into two groups. Group SME comprised patients (mean age of 8.8 years) treated with quad-helix appliance. Group RME comprised individuals (mean age of 8.9 years) treated with Hyrax expander. Digital dental models obtained immediately pre-expansion (T1) and 6 months after the active expansion period (T2) were used for measuring maxillary dental arch widths, arch perimeter, arch length, palatal depth, buccolingual inclination of posterior teeth and differential amount of expansion accomplished at the canine and molar regions. Inter-phase and intergroup comparisons were performed using paired t tests and t tests, respectively (p < 0.05). SME and RME caused significant increase of arch widths and arch perimeter. Arch length and palatal depth decreased nonsignificantly with SME but significantly with RME. Buccal tooth inclination was significant only for maxillary deciduous canines in both groups. The quad-helix appliance showed a significant differential expansion between anterior and posterior regions. No differences were observed between SME and RME for all variables. Differences were not found between the dentoalveolar effects of SME and RME in patients with BCLP. SME demanded a greater therapy time compared to RME. Both expansion procedures can be similarly indicated to correct maxillary arch constriction in patients with BCLP in the mixed dentition.