Objectives: To evaluate systematically the effectiveness of miniscrew-supported maxillary incisor intrusion compared with other nonsurgical intrusive mechanics for deep-bite correction.
Materials and methods: Unrestricted electronic searches in Embase, Web of Science, MEDLINE, LILACS, and Cochrane's CENTRAL as well as manual searches were conducted up to August 2019. Only randomized clinical trials (RCTs) were included. Study selection, data extraction, and bias assessment were done by two independent reviewers. The Cochrane risk-of-bias tool was used, and the quality of evidence was graded using the GRADE approach. A random-effects meta-analysis of continuous data, with its 95% confidence intervals (CIs), was used.
Results: Seven RCTs were included in the quantitative synthesis, and the overall quality of evidence was very low to low. When compared with intrusion arches, miniscrews resulted in a more efficient deep-bite reduction with a standardized mean difference (SMD) of -0.48 (95% CI, -0.89 to -0.07). When miniscrews were used, a statistically significant difference was observed favoring less maxillary molar extrusion (SMD, -0.86; 95% CI, -1.46 to -0.27) and more incisor intrusion as measured from centroid to palatal plane (SMD, -0.95; 95% CI, -1.41 to -0.49). Results also showed a statistically nonsignificant difference regarding the amount of resultant root resorption between miniscrews and intrusion arches.
Conclusions: There is weak evidence indicating efficient deep-bite correction using miniscrews. Root resorption seems to be an associated adverse effect that occurs regardless of the intrusive mechanics used. These conclusions should be viewed with great caution as further well-designed long-term research is recommended.
Keywords: Deep-bite malocclusion; Intrusion; Mini-implants; Miniscrews; Root resorption; Systematic review.