Bone mechanical behavior around dental implants: Densification and deformation follow-up by in-situ computed tomography

The state of bone tissue around dental implants is a crucial factor influencing their early clinical outcomes. Currently, this state is mainly defined by its primary stability, both in terms of biomechanical analysis and clinically. The clinical methods used for quantifying this stability-such as the Implant Stability Quotient (ISQ) and Insertion Torque (IT)-are indirect measures. While these methods provide insights into the overall mechanical behavior of the bone-implant system, they do not account for the impact of implant morphology on the surrounding bone. The method presented here aims to analyze the peri-implant bone using image analysis and volume correlation techniques combined with computed tomography to assess the bone strain field and densification resulting from dental implant placement. The study utilized two types of implants with distinct designs-one cylindrical and the other self-tapping-on five iliac crest bone samples harvested from butcher pigs. The results indicated that the self-tapping implant caused significantly greater bone densification near the implant compared to the cylindrical one (46% of densification in the first 30 μm, against 21% for cylindrical implant). Additionally, the volume of strained peri-implant bone appeared to be larger for the self-tapping implant (38% of the volume was mechanically affected above 0,5% VM strains for self-tapping implant, against 31% for the cylindrical implant), though this difference was not statistically significant. Furthermore, established descriptors from the literature struggled to effectively differentiate between the two implant types. Despite the study's limitations, the proposed method shows promise for distinguishing implants based on the densification and deformation of peri-implant bone, and can serve as a complementary approach to standard ISQ and IT measurements.