Bone-anchored maxillary protraction to correct a class III skeletal relationship: A multicenter retrospective analysis of 218 patients.

This study evaluated the impact of class III correction by elastic traction on four miniplates and the failure rate of bone-anchored miniplates in nonsyndromic patients. A total of 218 patients (112 males and 106 females; average 11.4 years), treated by 38 orthodontists, received four miniplates (total 872 miniplates) from 2008 to 2016 at three maxillofacial centers in two countries. Factors affecting the success and failure of the miniplates were retrospectively examined and skeletal changes on cephalometric radiographs examined for 52 patients. Elastic traction was performed for 22.9 months, on average. The miniplate survival rate was 93.6%; 25.7% of the patients suffered failure of one of the miniplates. Postoperative antibiotics and placement of the neck of the miniplate in the attached gingiva significantly improved the success rate. Miniplate failure was six times higher in the maxilla and occurred more in younger patients. Self-drilling screws were significantly better than self-tapping screws for fixing the miniplate. Small cephalometric changes were seen: SNA (+1.9°), SNB (+0.4°), ANB (+1.4°), Wits analysis (+1.3 mm). In conclusion, bone-anchored maxillary protraction on four miniplates is an effective method for correcting a class III relationship, but has less skeletal effect than previously reported in the literature.
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