Robotics in implant dentistry: stress/strain analysis - system overview and experiments

摘要

Purpose - Implant surgery is generally accepted as the best technique for complete teeth replacement. However, it is also the most demanding technique to implement and the most onerous to the client. It would be helpful to reduce costs and simplify procedures in order that the general public could benefit from implant dentistry. This paper reports a robotic system developed with the objective of studying stress/strain distribution caused by implants inserted in blocks of a polymer. The polymer exhibits the same mechanical properties of the human mandible bone. Design/methodology/approach - The system includes an industrial robot manipulator, a data acquisition board, strain gauges for stress/strain evaluation and a force/torque sensor (equipped with accelerometers) placed on the robot wrist. The objective is to optimize the number of implants and their placement/orientation, contributing in this way to reduce the overall cost of implant surgery. The system is presented in detail and explored for drilling and implant insertion. Findings - The preliminary results are encouraging and indicate the usefulness of the system. The three presented situations correspond to general clinical procedures and, as can be concluded from the preliminary results, the intensity of the applied forces increase with the inclination of the drilling tool. Since, the depth of the holes is the same, it can be also concluded that the dissipated energy is superior in the 30° hole. Apart from inclination all the other properties remain constant during the force evaluation; therefore, we expected that during the perforation of the 30° hole the temperature should raise more than in the other types of holes. This aspect will be addressed in detail in the near future (just by carefully monitoring the temperature) because living tissues should not be submitted to temperatures greater than 42℃. The observed fluctuation in the modulus of the force during a drilling cycle suggests that the material is not homogeny. The results indicate that the strain is larger in the vertical load. This might be related with the fact that inclined applied forces imply a distribution of the strain/stress forces at least for two directions. Research limitations/implications - Further work will include more sensors to obtain all the data. Practical implications - This will be of interest to the implant industry, since low prices will significantly increase the market and consequently the need for implant products. Currently, implant surgery as well as teeth replacements are based on a few general rules that, very often, do not take into account the specific needs of the patient. This happens independently of clinician expertise, which does not have enough biomechanical information to plan the number, location and orientation of implants in a specific surgery. Consequently, in most of the cases the needs are overestimated, to guarantee long-term success, which implies expensive procedures and more discomfort for patients. Originality/value - This work reports on a robotic system to simplify implant procedures.