Failure of miniscrews installed in maxilla and mandible: a systematic review and meta-analysis

Objective: The aim of this systematic review was to compare the clinical failure rate of orthodontic miniscrews in maxilla and mandible. Material and Methods: Randomized controlled trials of patients in orthodontic treatment, which required miniscrews for orthodontic intervention reporting the failure rate of miniscrews in the maxilla and mandible were searched in Pubmed database. Two authors independently reviewed all identified titles and abstracts for eligibility. Comparison between failures in maxilla and mandible were estimated using pairwise meta-analysis to calculate the relative risk (RR) of failure and the 95% confidence intervals using a random-effect model. The reports of randomized trials were assessed for bias using the Cochrane risk of bias tool. Results: Four studies fulfilled the eligibility criteria. 299 patients with a total of 628 miniscrews installed were included in the analysis. The analysis showed a 0.55 RR (95% CI 0.23–1.29) and I2 = 85%. All studies had an unclear risk of bias regarding to the two following items: allocation concealment, blinding of participants and personnel. All studies had a low risk of bias with regard to incomplete outcome data and selective reporting. The results did not demonstrate statistical difference between risk of failure of miniscrew between maxilla and mandible. Conclusion: The results of the meta-analysis showed that miniscrews installed in maxilla presents reduced risk of failure. A tendency of higher number of failures in mandible was also demonstrated. However, results should be interpreted with caution because of the very low quality of included studies and the differences among methodologies. KeywordsMeta-analysis; Orthodontic anchorage procedures; Review.