Coefficient of efficiency and effectiveness of functional appliances in class II malocclusion treatment :...

To evaluate the coefficient of efficiency and effectiveness of removable and fixed functional appliances in class II malocclusion treatment.

Search of studies in five databases (Medline via PubMed, Cochrane library, LILACS, SCOPUS, and SciELO) that measured mandibular skeletal changes following functional therapy was conducted until 15 April 2024.

All study designs including randomized and controlled clinical trials (RCT), prospective and retrospective studies were included. Data were extracted independently by two authors from studies that fulfilled the inclusion criteria. Mandibular length changes of class II patients treated with functional appliances were collated for each retrieved study.

From 6796 potentially eligible studies, 90 were considered for this systematic review. Four were RCTs which were graded with the Cochrane risk of bias tool. Three were assessed as having low and one as having moderate risk of bias. The other 86 studies were graded with the modified Downs and Black tool which revealed that 47 showed low, 38 low/moderate, and 1 a moderate risk of bias. The most commonly assessed appliances were the Twin Block which was used on 783 patients, the Frankel appliance on 573, the Herbst appliance on 530, the Activator on 449, the Forsus appliance on 394, the MARA appliance on 202, and the Bionator on 133, for a total of 3064 treated patients.

This systematic review provides conclusive evidence that the Twin Block appliance demonstrated the highest coefficient of efficiency among all the evaluated appliances (0.46 mm/month), while the Forsus fatigue resistant device (FFRD) had the highest coefficient of efficiency among the fixed functional appliances (0.41 mm/month).