Implants for orthodontic anchorage: success rates and reasons of failures.

INTRODUCTION: The aims of this study were to analyze the success rate of mini-implants and miniscrews and to report the reasons behind them. MATERIALS AND METHODS: An electronic literature search from PubMed databases and a hand search in implant- and orthodontic-related journals were performed until December 31, 2011. Human clinical studies in English that reported temporary anchorage devices used for orthodontic purpose with at least 6 months follow-up were included. In addition, the minimal number of implants had to be at least 10. Implants placed in maxilla, mandible, and hard palate were included. RESULTS: The initial search resulted in 847 articles, of which 46 were further evaluated. Finally, 29 studies were qualified and classified into 2 groups: implants placed in maxilla and mandible (group 1) and implants placed in hard palate (group 2). A meta-analysis performed for groups 1 and 2 showed 87.8% and 93.8% survival rate, respectively. In addition, the most common cause for implants failure was surgery-related factors. CONCLUSION: Mini-implant survival rate is location dependent, with those placed in the palate showing higher success rates. In addition, failures most commonly occur because of surgery-related factors.