Laser ablation of bone for implant osteotomy preparation-modeling and an ex vivo validation study

Mechanical drilling is currently a universal standard for implant osteotomy site preparation. Without proper cooling, high frictional heat can be generated inside the bone during drilling which may be detrimental for osteocyte survival. Mechanical fracture of bone near a drill bit surface can also impede the osseointegration process. Our new concept is to use a rapid laser ablation model for dental implant osteotomy preparation to minimize adverse effects on the bone from mechanical and thermal damages. A mathematical model was developed to detail the temperature and energy distribution within bone under laser irradiation. Thermal and energy transfer in bone was predicted during laser interaction using finite element simulations. Various parameters of laser irradiation settings were analyzed. The best designed laser irradiation condition was derived from our theoretic modeling in terms of thermal and mechanical characteristics for osteotomy. We also validated our theoretical prediction with an ex vivo animal bone study. We conclude that a smooth and clean surface was successfully formed with laser power of 10 W, scanning speed of 600 mm/s, and scanning interval of 20 μm. We also achieved the highest removal rate of 0.63 mm³/s. Our finite element model demonstrated that it could effectively predict the temperature and energy distribution during an osteotomy drilling. Our validated model can potentially offer a remarkable approach for a non-contact dental implant site preparation with minimal mechanical and thermal damages to the adjacent bone tissue which likely can augment bone repair and regeneration during an osseointegration process.