Rule-based parametric modelling of natural teeth: An automated CAD approach and its application in finite element...

Finite element analysis is widely used in dental research to investigate the biomechanical behaviour of teeth and surrounding tissues. However, creating simulation-ready models of natural teeth from scan data remains labour-intensive, particularly when structures not captured by intraoral scanning, such as roots and pulp cavities, must be modelled separately. In this study, a rule-based parametric modelling approach for generating simulation-ready tooth models from intraoral scan data was developed. Implemented in Grasshopper 3D, this approach creates complete tooth geometries, including roots and pulp cavities, based on scanned crown surfaces and literature-derived parameters. The parametric design enables variation of tooth attributes and was applied to a right maxillary first premolar to investigate the effects of root length, root number, periodontal ligament (PDL) thickness, PDL material model (linear-elastic and hyperelastic), and clinical attachment loss (CAL) on stress distributions in the alveolar bone and PDL using finite element analysis. Greater CAL led to higher compressive stresses in the alveolar bone and PDL. A higher PDL thickness led to higher compressive and tensile stresses in the alveolar bone. Root length mainly influenced stresses at the root apices in the alveolar bone. Shorter roots led to higher compressive stresses in the PDL. The number of roots affected the stress distribution at the furcation and at the level of the root apices. The hyperelastic PDL model produced near-zero tensile stresses in the PDL. The proposed approach eliminates manual CAD model creation and enables exploration of tooth variants for biomechanical analysis.