Page 84 - Demo

Chapter 582Calibration, reference frame and validationAt the beginning of each experiment the location and orientation of each tooth was calibrated. To do so, the robot arm, with a straight periosteal elevator mounted in the forceps-holding device, was positioned parallel to the axis of each tooth and in the center of each crown. The expected rotational center was estimated 2mm below this point. A mathematical translation from the center of the force/torque sensor to the center of rotation of each tooth was performed. If necessary, axis were mirrored to align the tooth frames in clinically relevant dimensions. For example, a force in buccal direction on a left upper first molar needs to be mirrored along the mesiodistal axis to enable a useful comparison with the buccal forces on a right upper first molar. The mathematical translations were validated on a mounted plastic jaw. Exaggerated forces and torques in all directions were performed on all four first molars in a standardized order. After translation, it was checked that the tooth frames were correctly aligned for all quadrants. Data availabilityThe processed data required to reproduce these findings are available to download from https://www.doi.org (digital object identifier: 10.4121/16847026, license: CC BY 4.0).ResultsBasic characteristicsIn total seven fresh-frozen Caucasian specimens were obtained for this study on which 127 experiments were performed. In 110 (86.6%) of these experiments full data was successfully recorded. The largest part of these procedures happened uneventful (n=94, 85.5%). In other experiments data was successfully recorded but some complications were present of which a fracture of the boney wall was seen most frequently (n=9, 8.2%) and less often crown or root fractures (combined n=9, 8.2%). Most teeth had sound periodontal (n=60, 54.5%) and restorative (n=45, 42.7%) states. A complete overview of the basic characteristics of the experiments material is supplied in appendix table A.1.Tom van Riet.indd 82 26-10-2023 11:59