Miniscrews and mini-Implants success rates in orthodontic treatments: a systematic review and meta-analysis of several clinical parameters.

The aim of the following research is to conduct a systematic review in order to update the actual knowledge about miniscrews in the clinical practice, in particular about their stability and reliability. Methods: An electronic search in the main database was performed up to February 10th, 2015 to identify articles that complied with the parameters set out in the protocol. The selection included studies showing the success rate of mini-implants for a sample exceeding 5 miniscrews, giving a definition of success, using implants with a diameter <2.5 mm and applying forces for at least 3 months. The success rate was considered as a paradigm and was divided by the following variables namely age and sex of patients, length and diameter of the miniscrew, location and method of placement of mini-implants, time and amount of loading. A meta-analysis was performed to combine comparable results. Results: 65 clinical trials that collected 4080 patients and 8524 screws were included in the study. The mean weighted overall success rate was 86.75 ± 8.48%. The maxilla represents a better placement site for insertion than the mandible. The lengths of the miniscrews do not compromise the success rate. Conclusions: In all 65 articles miniscrews could be used to help orthodontic treatment. The usage of miniscrews for a stable period of 3 months showed the highest success rates. Screws less than 8 mm in length and 1.2 mm in diameter should be used under restricted conditions, while miniscrews longer than 10 mm could be avoided.