Soft Tissue Changes in Patients With Dentoalveolar Protrusion Treated With Maximum Anchorage: A Systematic Review and Meta-analysis.

OBJECTIVE: This meta-analysis aimed at comparing the angular and linear changes of soft tissue profile using conventional anchorage techniques and mini-implant (MI)-based space closure in patients with dentoalveolar protrusion.

MATERIALS AND METHODS: Electronic databases, viz. PubMed, Embase, and Cochrane Central Register of Controlled Trials, were searched for relevant literature from their inception to December 2017 according to the specific inclusion and exclusion criteria. The following Medical Subject Heading terms were used for searching: "skeletal anchorage", "temporary anchorage devices", "miniscrew implant", "mini-implant", "micro-implant". Selected randomized control trials (RCTs) were assessed for their quality using Cochrane's Risk of Bias Tool, whereas the Newcastle-Ottawa scale was used for non-RCTs. Standardized mean difference (SMD) and 95% confidence interval (CI) were obtained with either fixed- or random-effects models based on the heterogeneity of the included studies.

RESULTS: A total of 5 articles (2 RCTs with moderate risk of bias and 3 high-quality non-RCT studies) were included in the final analysis. The nasolabial angle had significantly greater changes in the MI group than in the conventional anchorage group (SMD = 0.68, 95% CI = 0.39 to 0.97, P < .0001). Significantly higher retraction of the upper lip was seen in the MI group than in the conventional group (SMD = -0.51, 95% CI = -0.84 to -0.18; P = .002). No significant difference was seen in the facial convexity (SMD = -0.34, 95% CI = -0.76 to 0.07, P = .106) and lower lip retraction (SMD = 0.28, 95% CI = -1.72 to 2.28, P = .784) between the groups.

CONCLUSION: It was seen that MIs facilitated favorable soft tissue profile than the conventional anchorage devices. However, more high-quality studies are warranted to confirm the clinical effectiveness of MIs.