Correlation of insertion torques with bone mineral density from dental quantitative CT in the mandible

OBJECTIVE: The aim of this study was to establish a correlation between bone mineral density measured preoperatively with dental computed tomography (CT), and insertion torque of screw-shaped dental implants. MATERIAL AND METHODS: In eight human mandibles obtained postmortem, bone mineral density (BMD) was measured with dental quantitative CT (DQCT) and correlated with insertion torque values at 45 implant sites during insertion of screw-shaped dental implants (Brånemark System MKIII, Nobel Biocare, AB, Göteborg, Sweden). RESULTS: A significant correlation (r=0.86, P<0.001) between BMD and torque values was observed, indicating that local BMD at a specific implant position is related to the supportive capacity of the jawbone. BMD exhibited no correlation with bone height or position. CONCLUSION: The noninvasive assessment of BMD using a DQCT scan employing a low-dose protocol may be used to estimate expected primary stability depending on BMD, implant type and preparation procedure. These data may therefore help the surgeon to select the optimum implant position, implant type and operation technique.