Combining the effects of undersized drilling and bone density on implant insertion torque

Abstract

Aim: This study evaluated the influence of surgical undersized drilling on insertion torque of an implant system at low bone density. Methods: Implant site preparations were made in two polyurethane foam blocks with different densities, where two preparation techniques were considered: Control group (C): conventional drilling, following the manufacturer's instructions; and Group (E): undersized drilling, experimental technique using a final surgical drill with reduced diameter. The artificial bone blocks were selected based on density: D1 (0.64 g/cm3) and D2 (0.32 g/cm3). Three groups were considered according to the preparation technique and bone density used (n=10): CD1 - conventional drilling technique in artificial bone with higher density; CD2 - conventional drilling technique in artificial bone with lower density; and ED2 - undersized drilling in artificial bone with lower density. External-hexagon implants (11 × 4 mm) were inserted and the insertion torque values were measured using a digital torque-meter. Data were submitted to one-way ANOVA followed by Tukey's test (α=0.05). Results: The results showed significant statistical differences between groups (p < 0.001), where the highest insertion torque was found for the Group CD1 (48.9 Ncm) followed by Group ED2 (22.6 Ncm) and Group CD2 (11.7 Ncm). Conclusions: The undersized drilling technique for implant site preparation leads to increased insertion torque on low bone density.