Abstract

The purpose of this study was to experimentally measure and simulate thermal diffusion in the surrounding of specific dental drills with cylindrical and conical drills. The investigation was performed under different drilling conditions, with and without cooling and at different revolution speeds. During the experimental investigation, drilling into a polyurethane (PUR) foam block, was performed with and without cooling, and at three different revolution speeds, 800 rpm, 3,000 rpm and 5,000 rpm. Finite element method (FEM) simulation of the thermal diffusion during drilling into PUR foam was also performed. As a result, different temperature diffusion was found in the surroundings of the individual drills. During specific drilling conditions, some of the drills produce very high heat, as opposed to the other tested drills. The results from the numerical FEM analysis are consistent with the experiments, and it is evident that the shape of the drill and the drilling conditions affect the results. The measurements in our experiment were performed under specific conditions that resembled mechanical drilling and did not match the reality of drilling in dental surgery, which is very often interrupted and the drilling force is reduced by the dentist’s hand. The actual temperature is probably much lower. The finite element (FE) analysis of temperature rise during drilling can be useful for shape optimization of the drill when the target function is lower in temperature.

摘要

本研究的目的是通过实验测量和模拟带有圆柱形和锥形钻头的特定牙钻周围的热扩散。调查是在不同的钻井条件下进行的，有冷却和没有冷却以及不同的转速。在实验研究期间，在冷却和不冷却的情况下，以三种不同的转速（800 rpm、3,000 rpm 和 5,000 rpm）对聚氨酯 (PUR) 泡沫块进行钻孔。还对钻入 PUR 泡沫期间的热扩散进行了有限元法 (FEM) 模拟。结果，在各个钻头的周围发现了不同的温度扩散。在特定的钻探条件下，与其他经过测试的钻头相比，一些钻头会产生非常高的热量。数值有限元分析的结果与实验一致，很明显，钻头的形状和钻孔条件会影响结果。我们实验中的测量是在类似​​于机械钻孔的特定条件下进行的，与牙科手术中钻孔的实际情况不符，因为牙医的手经常会中断钻孔并降低钻孔力。实际温度可能要低得多。当目标函数温度较低时，钻孔过程中温升的有限元 (FE) 分析可用于优化钻头的形状。我们实验中的测量是在类似​​于机械钻孔的特定条件下进行的，与牙科手术中钻孔的实际情况不符，因为牙医的手经常会中断钻孔并降低钻孔力。实际温度可能要低得多。当目标函数温度较低时，钻孔过程中温升的有限元 (FE) 分析可用于优化钻头的形状。我们实验中的测量是在类似​​于机械钻孔的特定条件下进行的，与牙科手术中钻孔的实际情况不符，因为牙医的手经常会中断钻孔并降低钻孔力。实际温度可能要低得多。当目标函数温度较低时，钻孔过程中温升的有限元 (FE) 分析可用于优化钻头的形状。