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Chapter 460Material and MethodsChallenges in detailed measuring of tooth removalSeveral challenges had to be overcome during the design of the measurement setup. Dental surgeons use a combination of high forces and subtle motions to loosen a tooth from its bony socket. It is necessary to measure these sub-millimeter movements in three dimensions and at a high rate to be able to analyze movements in full detail and, for example, en- able analysis of adverse events like tooth fracture. These measurements should take place without restricting dental surgeons in their movements in any way. Forces and torques should be measured in three dimensions in the center of rotation of the tooth, simultaneously with the movements. Clinically important parameters such as periodontal health, amount of roots, root size, age of the patient, and restorative state should be easily integrated into the measurements. Preferably, these measurements should all be performed on patients in an in vivo setup.Multiple sessions with a team of clinicians, mechanical engineers and computer scientists led to inevitable com- promises in the setup. One of the major concessions to the ideal setup was the use of an in vitro measurement setup. Simultaneous and reproducible recordings of position/orientation/force/torque measurements are essential in this fundamental research. Compared to in vitro measurements, accurate sub-millimeter movement tracking and registration of forces/torques and their directions in vivo is questionable. One of the main issues is that the mobility of the patient is difficult to compensate for, which is especially true for the lower jaw, which is not rigidly fixated to the human skull. The force/torque sensor would need to be integrated in the forceps between the surgeon’s hand and the tooth, which is unrealistic due to very limited space and high forces. Next to that, in vivo tooth removal requires considerable counterforce from the surgeons’ second hand, which would interfere with the force measurements. Finally, we made the assumption, that the forceps and the tooth are rigidly connected once the tooth is grabbed. Therefore, we do not need to measure the movement of the tooth itself and can place the force/torque sensor under the jaw. To capture the clinicians’ movement, several techniques were proposed of which optical tracking (infrared) and robot technology were the most promising. Robot assisted motion capture was preferred due to the high accuracy associated with robotic positional measurements. Next to that, by rigidly fixating the standard dental forceps to the end-effector, the surgeon can hold the forceps as they would do in clinical circumstances. Compared to optical trackers it Tom van Riet.indd 60 26-10-2023 11:59