Objectives: To determine whether the success rate and primary stability of surface-Treated miniscrews differ from those of nontreated miniscrews. Materials and Methods: Patients who required one or more miniscrews for the same reason in each quadrant were recruited into a single-blinded, split-mouth, randomized, controlled trial with a 1:1 allocation ratio. Self-drilling miniscrews with two surface types were used: Those with no surface treatment, and those with an acid-etched surface treatment. The cumulative success rate and primary stability of each type of miniscrew were examined, and factors potentially affecting the success and failure of miniscrews were investigated. Results: Forty patients were included in the study, with a total of 98 orthodontic miniscrews. The overall success rate was 88.8%, and the respective success rates for acid-etched and machined surface miniscrews were 91.8% and 85.7%. The respective mean insertion torques were 13.62 6 5.95 N-cm and 13.38 6 4 N-cm, and periotest values measured immediately after insertion were -0.50 6 2.77 for acid-etched miniscrews and -0.28 6 3.36 for machined surface miniscrews. There was no significant difference in the mean insertion torques and periotest values according to surface treatment and jaw. Conclusions: Neither the success rate nor the primary stability of acid-etched surface miniscrews and machined surface miniscrews differed significantly. There is a high possibility that miniscrews will fall out in patients who have an open bite or those who require total distalization. & copy 2019 by The EH Angle Education and Research Foundation, Inc.
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