Influence of bone drilling parameters on the thermal stress distribution

Material removal through the drilling mvolves two important processes. The fírst one is drilling of material by cutting edges ofthe drill bit and the second one is the fi-iction generated by the contact between drill bit and hole wall of the material. Both processes lead to heat generation during drilling. In clinicai practice, drilling procedures and high-speed cutting tools are often applied on boné tissue. These operations are associated to complications such as thermal osteonecrosis due to the excessive heat generation and mechanical damage due to the excessive leveis of penetration force. The development of additional tools for accurately simulating the drilling is essential to predict the risk of thermo-mechanical damage during boné drilling. This paper investigates the thermal and mechanical damage in boné tissue induced by different parameters. An experimental and numerical approach of boné drilling hás been conducted. A three-dimensional dynamic numerical model was developed to simulate the mechanical and themial stresses generated during the drilling. The numerical model incorporates the geometrical and dynamic characteristics involved in the drilling processes. The numerical analysis hás been validated by experimental tests using polyurethane foam materiais with similar mechanical properties to the human bone.This research was supported by the Portuguese Foundation of Science and Technology under research project UID/EMS/50022/2013.