Normal Stiffness Analysis of Antagonistic Molars with Crown Prosthesis in Chewing Robot

The normal stiffness between teeth is an important parameter to design an effective force controller of chewing robot. The normal stiffness analysis of antagonistic molars with crown prosthesis in chewing robot was carried out. Right first antagonistic molars of the dental model were modelled by raster scanning, 3D reconstruction, and separation. Then an occlusal kinematics analysis was made in Occlusal Fingerprint Analyser software, which turned an initial statistical chewing trajectory into an optimized chewing trajectory matching the teeth morphology. Next, normal direction along the optimized chewing trajectory was defined for calculating the normal force by the dynamic finite element method. Finally, the normal stiffness at the feature time point was calculated by data processing. The result showed that in the intrusive and excursive phase, the normal stiffness kept 2.5-7.5 MPa, and in the medial phase, it increased to 47.5-60.0 MPa.