Simulation and modeling of dental bur force and vibration at enamel and dentin layers

Tooth restoration is the most frequent operation in dentistry. During this process, the dentist removes chip from carious or damaged restoration part of tooth by a high speed rotating tool. The forces generated due to tool and tooth layers contact are called cutting forces. In medical works, knowing the magnitude of cutting forces is very important, as many efforts has been done in this area to measure those experimentally. However, a lot of time, money, and energy would be require for experimental tests. The cutting force varies at different tooth layers and the dentist has no feedback on which layer is under milling operation (objective layer). In other words, a dentist detects objective layer based on experiments and physical sense during the operations. Consequently, online detection of objective layer is a challenging issue. The main object of current research is the simulation of force and vibration of dental bur. Vibration signals are a powerful source of information that can be used to detect dental layers. To the best author's knowledge, the specific cutting force coefficients for the two main dental layers are obtained for the first time in current study. In addition, vibration and force in the two main layers of the tooth are compared and analyzed using the Timoshenko beam theory, the milling force equations and the dynamic chip thickness. The results of this effort can be used to improve the quality and efficiency of dental restoration and to give an initial view on producing an intelligent hand-piece.