Effect of coring conditions on temperature rise in bone
Coring is an oldest surgical procedure used for dental implants, bone biopsy retrieval and removal of cancerous bone tissues. As a cutting process, coring induces heat. If this temperature rise induced by the cutting heat exceeds the threshold value; it induces thermal damage to bone cells and tissues adjacent to the cutting zone. Additionally, it may degrades the mechanical integrity of bone and hence reduce the toughness of the tissue. The amount of heat generated during coring is dependent on the cutting conditions: i.e. cutting speed and depth of cut. However, it is still unclear how the coring conditions are related to the temperature rise in bone and its effect on the toughness of the tissue. To address these issues, this study was performed to examine such effects by measuring changes in the temperature rise and the specific cutting energy as the function of the cutting speed and the depth of cut in coring bovine cortical bone specimens. Since temperature rise is induced by the cutting heat generated in the cutting zone, which is moving within bone as the coring tool rotates, it is difficult to directly measure the temperature rise in the heated zone in bone. To address this issue, a thermocouple was inserted into bone specimens on the aide of coring path prior to coring in order to measure the temperature rise a certain distance away from the cutting zone. Using the information, the temperature rise in the cutting zone was estimated by extrapolating the experimental result based on a moving-point-heat-source solution provided in the literature. In addition, this solution was used to predict the thermal damage zone and thresholds for coring conditions. Finally, the experimental results indicate that toughness loss of bone is correlated with the temperature rise during coring process and it depends on the cutting conditions, such as cutting speed and depth of cut.