Stability of maxillary protraction therapy in children with Class III malocclusion: a systematic review and meta-analysis

Objective: The objective of this study was to evaluate the stability of treatment effects of maxillary protraction therapy in Class III children.

Materials and methods: Multiple electronic databases were searched from 01/1996 to 10/2016. Randomized clinical trials, controlled clinical trials, and cohort studies with untreated Class III controls and a follow-up over 2 years were considered for inclusion. The methodological quality of the studies and publication bias were evaluated. Mean differences and 95% confidence intervals (CI) of six variables (SNA, SNB, ANB, mandibular plane angle, overjet, and lower incisor angle) were calculated.

Results: Ten studies were included in the qualitative analysis, and four studies were included in the quantitative analysis. Compared with the control group, after treatment, the treated group showed significant changes: SNA +1.79° (95% CI: 1.23, 2.34), SNB -1.16° (95% CI -2.08, -0.24), ANB +2.92° (95% CI 2.40, 3.44), mandibular plane angle +1.41° (95% CI 0.63, 2.20), overjet +3.94 mm (95% CI 2.17, 5.71) and lower incisor angle -3.07° (95% CI -4.92, -1.22). During follow-up, the changes in five variables reflected significant relapse. Overall, the treated group showed significant changes only in ANB +1.66° (95% CI 0.97, 2.35) and overjet +2.41 mm (95% CI 1.60, 3.23).

Conclusions: Maxillary protraction can be a short-term effective therapy and might improve sagittal skeletal and dental relationships in the medium term. But some skeletal and dental variables showed significant relapse during the follow-up period. Long-term studies are still required to further evaluate its skeletal benefits.

Clinical relevance: The study evaluated the medium-term stability of skeletal and dental effects of maxillary protraction in Class III children and discussed whether the therapy can reduce the need for orthognathic surgery.