Effect of drill speed on bone damage during drilling

The boné drilling is a common surgical procedure in clinicai intei-ventions including the dentistry. Although not a novelty in medicine, the penetration of a sharp tool in the boné tissue continues to be a clinicai and surgical challenge, as many pertinent questions still remain without solutions. Mechanical damage to the boné tissue is one of the common complication associafed with the drilling process [l]. An excessive force generated by a cutting tool can lead to the formation of microcracks and fractures, and even cause permanent damage in the boné tissue that, in tum, can delay postoperative recovery [2]. The main goal of this paper is to investigate the effect of drill speed on mechanical damage during drilling of solid rigid foam materiais, with similar mechanical properties to the human boné. Experimental tests were performed on biomechanical blocks instrumented with strain gauges in different surface positions during the drilling process. Finite element (FE) simulations were performed to simulate the drilling process and validated with experimental results.

Effect of different feed-rate in bone drilling: experimental and numerical study

The behaviour of bone tissue during drilling has been subject of recent studies due to its great importance. Because of thermal nature of the bone drilling, high temperatures and thermal mechanical stresses are developed during drilling that affect the process quality. However, there is still a lack information with regard to the distribution of mechanical and thermal stresses during bone drilling. The present paper describes a sequentially coupled thermal-stress analysis to assess the mechanical and thermal stress distribution during bone drilling. A three-dimensional thermo-mechanical model was developed using the ANSYS/LSDYNA finite element code under different drilling conditions. The model incorporates the dynamic characteristics of drilling process, as well as the thermo-mechanical properties of the involved materials. Experimental tests with polyurethane foam materials were also carried out. It was concluded that the use of higher feed-rates lead to a decrease of normal stresses and strains in the foam materials. The experimental and numerical results were compared and showed good agreement. The proposed numerical model could be used to predict the better drilling parameters and minimize the bone injuries.