Torque analysis of mini-screw implants placed with and without a pilot drill: A canine study

The objectives of this study were: (1) to compare the success rates of mini-screws placed with or without use of a pilot drill; (2) to evaluate the relationship between the success rate and the Implant Placement Torque (IPT) of mini-screws; and (3) to measure the removal torque of the mini-screws.;Results: A total of 33 mini-screws were placed. After 6 weeks of healing, the success rate for the control and test groups were 46.7% and 80%, respectively (difference not statistically significant). There was no statistically significant difference in the mean IPT values and the mean number of turns for failed and successful mini-screws. The difference between the mean IPT values at the 3rd turn during mini-screw placement in the successful and failed mini-screws (5.56 Ncm and 14.03 Ncm, respectively) was statistically significant (p<0.01).;Conclusions. In the group which a pilot drill was not used, the self-drilling mini-screw had a higher success rate than in the group which a pilot drill was used. The IPT value at the 3rd turn during mini-screw placement had an impact for the success of the mini-screw.;Key words. Orthodontic anchorage; temporary anchorage devices; screw; mini-screw; dental implants; placement torque.;Methods and materials. Six American foxhounds served as subjects in this study. Three OsteoMed mini-screws (1.6 mm diameter and 8 mm length) were planned to be placed in each side of the mandible between the roots of the teeth canine/premolar 1 (PM1), PM2/PM3, and PM3/PM4. The sites were randomly allocated in: (1) control group: miniscrews placed with pilot drill and (2) test group: mini-screws placed without pilot drill (self-drilling). The implant placement torque (IPT) and the number of turns performed by the screws during placement were measured. After a healing period of 6 weeks, the miniscrews were removed and the removal torque was measured.