Understanding the biomechanical response of progressive thread dental implants using multi-scale finite element analysis

Implant osseointegration is an important factor dictating its long-term efficacy, in situ. Along with various biological factors, it is greatly influenced by the mechanical stimulus at the peri-implant bone. This study aims to understand the biomechanical response of progressive thread dental implants using multi-scale-based finite element analysis employing macro and micro models of bone. µ-CT images of a cadaveric human mandible of its premolar region were obtained along with CT scan of the same region to generate computational models. Total six dental implants were designed having regular and progressive thread depths. Three different stages of healing of the bone-implant assembly were simulated parametrically. The biomechanical environment at the peri-implant bone was analysed considering the ‘Mechanostat’ hypothesis. The obtained results revealed that bone strain is significantly higher during the initial healing phase when the bone is weakest. During this phase, implant stress and its displacement in both buccolingual and coronoapical directions are also noticeably higher. Also, displacements of progressive thread implants were lower in all the healing phases compare to the implants with constant thread depth. The observations of this µFEA study highlight the clinical applicability of a progressive thread dental implant as it generates larger functional surface area thus engaging higher trabeculae and therefore suitable for weaker bone conditions. Furthermore, by comparing the stress values at bone and implant between the two bone models, the CT-based model having inhomogeneous material was deemed suitable as an alternative to computationally expensive µFEA.