Assessment of Primary Stability in Two Implant Designs

Objectives: To compare the effect of two dental implant designs (tapered and straight) on primary stability. Methods: In a clinical study, 7 patients received 24 Anthogyr dental implants (11.5 * 4 mm), 12 straight, and 12 hybrid (tapered), bilateral or proximal in the same jaw. Primary stability was assessed by measuring the insertion torque and by the Periotest device. An in vitro study was also made similarly, using dummy implants (12 straight, 12 tapered), inserted in the lower jaw of a calf. In this part, the removal force (pull-out) was also measured (using an Instron 1195). Values were compared using the t-test and ANOVA. Results: No statistical differences were found with respect to Periotest and removal force values between the two types of implant design. The tapered implant showed higher insertion torque with statistical significance. Conclusions: The tapered implant design showed higher primary stability which could be measured by the insertion torque test but by neither the Periotest nor by removal force.