Model-Free Detection of Penetration and Automatic Stop Control in Dental Implant Surgery Based on Differential Value of Torque

In dental implant surgery, operators should stop at the moment of the penetration of the bone without damaging other tissues especially in the maxillary sinus membrane located in between the alveolar bone and the sinus. Nevertheless, they are struggling with figuring out the timing of the stop. The classification of the type of bones in drilling is helpful for automatic stop control. In conventional research, the segmentation was performed based on the resistance force model. However, these methods suffer from inaccuracies since the theoretical parameters used for the model are not always equal to their real values. The accuracy detection sometimes deteriorates due to the error of parameters. This is one of the biggest risks the present automatic stop control methods have. This paper proposes the model-free detection of the moment of the penetration and automatic stop control based on variation of differential value of cutting torques. The effectiveness of the proposed method is validated by experiments.