Use of Haptic Feedback to Train Correct Application of Force in Endodontic Surgery

With the minute margins of error in endodontic surgery, training in manual dexterity and proper instrument handling are crucial components in the dental curriculum. Important parameters include tool path, tool angulation, and force applied. In this work, we focus on training of correct application of force. This is particularly challenging since the amounts of force used are on the order of tenths of Newtons, requiring a highly refined tactile sense and incorrect force can cause irreversible damage. Too great a force can cause overdrilling or in extreme cases perforation of the tooth. Too small a force can cause thermal irritation possibly resulting in tissue necrosis. Despite the importance of correct use of force, this is the dimension on which students receive the least tutorial feedback since force information is typically not available in traditional training settings. In this paper, we present an approach to using haptic feedback as a means to convey formative feedback on the correct application of force. Feedback is conveyed to the student graphically and the correct amount of force to apply is trained haptically. The simulator is rewound and the student is asked to redo the stage where the error occurred. Preliminary evaluation against a control group of students who received only feedback concerning outcome shows the feedback mechanism to be effective.