EFFECT OF SURFACE TREATMENT OF ORTHODONTIC MINI-SCREW IMPLANTS ON THEIR STABILITY; IN VIVO STUDY

Purpose: To evaluate the effect of anodization surface treatment on the stability of minimplants ( MIs ) during en-masse retraction.
Materials and Methods: The sample of this split mouth; clinical trial, consisted of 27 patients with an allocation ratio of 1:1. Forty five MIs (1.8 mm diameter and 8 mm length) were divided into: 27 MIs with surface treatment by anodization technique while the other 27 were with smooth surface (group B). Finishing, leveling and alignment, the surface treated MIs and the smooth ones were randomly inserted between the roots of maxillary 2nd bicuspid and 1st molar at the mucogingival junction on both sides of each patient. After two weeks healing period, bilateral extraction of maxillary 1st bicuspids were done. Closed coil spring was extended from the MI head to along hock secured onto the main arch wire between the maxillary lateral incisor and canine on both sides, delivering 200 g force per side to en-masse retract the upper anterior teeth. The average observation period lasted 9–12 months.
Results: In total, 40 of 54 minimplants were able to achieve the treatment goals. In group A, 22 (81.5%) mini-screw implants presented long-term stability, while in group B, only 18 (66%) minimplants were stable throughout the treatment. This difference was statistically significant (P =.0311). The total success rate for all inserted miniscrew implants was 74%.
Conclusion: Anodized surface treated orthodontic mini-screw implants are more stable than smooth surface one during en-mass retraction.