Effects Produced by Fixed Functional Appliances With and Without Skeletal Anchorage for the Treatment of Class II Malocclusion in the Growing Patient: A Review of Systematic Reviews

To summarise the scientific evidence from systematic reviews on the differences between fixed functional appliances (FFA) with and without skeletal anchorage for the treatment of Class II malocclusion in growing patients. A systematic search on six major databases was performed. Primary outcomes were changes in Co-Gn, SNB angle and the lower incisor inclination. ROBIS tool to assess risk of bias and GRADE instrument to assess evidence quality were used. Mean differences (MD) or risk ratios (RR) with their 95% confidence intervals were calculated from random-effects meta-analyses. A total of 10 systematic reviews were identified, six at high risk of bias, three at unclear risk of bias and one at low risk of bias. The meta-analysis with only RCTs studies indicated that FFA with skeletal anchorage did not produce a statistically significant increase in Co-Gn (pooled MD = +1.37 mm, 95% CI from −0.88 to 3.62; p = 0.23, I2 = 96%, three studies, GRADE low). No statistically significant differences were identified for SNB angle between FFA with and without skeletal anchorage (pooled MD = +0.31 degrees, 95% CI from −0.03 to 0.66; p = 0.08, I2 = 51%, three studies, GRADE low). FFA with skeletal anchorage showed a statistically greater decrease for lower incisor inclination (pooled MD = −5.03, 95% CI from −8.49 to −1.58; p = 0.004, I2 = 89%, four studies, GRADE low). Low evidence of findings from exclusively RCTs studies suggested that FFA with skeletal anchorage could reduce the lower incisor inclination with a greater percentage of complications. However, no significant differences were found for mandibular dimensions and mandibular protrusion between FFA with and without skeletal anchorage.