Relationship between the CT Value and Cortical Bone Thickness at Implant Recipient Sites and Primary Implant Stability with Comparison of Different Implant Types

Background: Studies have shown that bone quality at the implant recipient site can influence primary stability. Purpose: The aims of this study were to explore the quantitative estimation of the primary stability of implants preoperatively using CT values and to examine the effect of different implant designs with recommended socket preparation on primary stability. Materials and Methods: Forty-four fresh porcine femoral heads were prepared. The bone surrounding implant sockets was preoperatively evaluated by helical CT. Forty-four implants (φ 4.3×10mm), 22 straight and 22 tapered, were placed according to the manufacturer's instructions. The insertion torque value (ITV), implant stability quotient (ISQ), and removal torque value (RTV) were recorded as indicators of primary implant stability. Results: Significant correlations and linear relationships were found between the CT value and ITV, ISQ, and RTV for both straight and tapered implants (Spearman's correlation coefficient, p<.001; linear regression analysis, p<.01). Tapered implants had a significantly higher ITV than straight implants (analysis of covariance, p<.01). Conclusions: Obtained results suggest that the primary stability of implants could be quantitatively estimated using the CT value preoperatively, indicating the CT value of bone surrounding an implant can contribute considerably to implant planning and design choice in clinical situations.