Class II treatment with functional appliances: A meta-analysis of short-term treatment effects

The efficacy of functional appliances and changes produced by their application are still the subject of controversy. Functional appliances encompass a range of removable and fixed devices that are designed to create three-dimensional changes in the dentition and development of the jaws. This meta-analysis aims to analyze current literature up to January 2013 to provide evidence regarding the effects of functional appliances (removable FA and fixed FA). A literature survey of articles was initiated with meta-analysis using the random effect model (REM) along with heterogenesis and sensitivity analyses. Articles that met the inclusion criteria included 24 for RFA and 7 for FFA. The total number of subjects evaluated were 1469 (780 treated and 689 controls) for RFA and 353 (219 treated and 134 controls) for FFA. The results from the REM showed significant effects on mandibular skeletal (Co–Gn: 2.29 mm, p < 0.0005; SNB—1.43°, p < 0.0005; and N Perp Pg—2.08 mm, p < 0.006) and dental changes (L incisor horizontal—1.34 mm, p < 0.0005). Significant maxillary dental changes (U molar horizontal—2.84 mm, p < 0.0005) were only observed for FFAs. Sensitivity and chi-square tests also confirmed these findings. The analysis of the effect of treatment by FFAs and RFAs versus untreated controls showed statistically significant short-term effects.