Standardized digital models for biomechanical analysis

Tooth preparation and dental prosthesis design are challenging tasks often performed manually. Existing CAD methods are complex and limited in generating standardized models from anatomically complex structures. This study aimed to develop a user-friendly digital workflow for creating standardized models for in silico and in vitro biomechanical analyses, with relevance to digital and CAD/CAM dentistry.

The maxillary right central and lateral incisors of a typodont model are scanned using a laboratory scanner, and the data are converted into non-uniform rational B-spline (NURBS) format using CAD software. The NURBS data are modified to achieve digital tooth preparation, and a resin-bonded fixed dental prosthesis is designed with the lateral incisor as a pontic. A second model is created by incorporating a dimple into the existing tooth preparation model. The prepared tooth surface is used to create a cement space and prosthesis.

The final CAD models of the prepared teeth and prostheses were identical except for the dimple. The cumulative root-mean-square (RMS) deviation between the scanned and NURBS data was 0.6 μm for the central incisor and 1.5 μm for the lateral incisor.

This semi-automatic NURBS conversion workflow provides a practical digital approach for generating standardized tooth preparation and prosthesis models. Its relevance to digital and CAD/CAM dentistry lies in the precise control of preparation geometry, cement space, and prosthesis design, as well as in the generation of editable models suitable for biomechanical analysis, prototyping, and downstream CAD/CAM workflows.