A latent variable deep generative model for 3D anterior tooth shape.

Purpose: To introduce a 3D generative technology, PointFlow, which can generate 3D tooth shapes that integrate with conventional digital design workflows, and to evaluate its clinical applicability for tooth reconstruction.

Materials and methods: A dataset of 1337 3D scans of natural anterior teeth was used to train a deep generative model (DGM) called PointFlow. This model encodes complex 3D tooth geometries into compact latent codes that efficiently represent essential morphological features. PointFlow models these latent codes as a continuous distribution, enabling the generation of new, realistic tooth shapes as point clouds by sampling from this latent space. The generative quality of the outputs was quantitatively evaluated using seven 3D shape metrics by comparing both the generated and training samples to a validation set. Clinical applicability was further explored by reconstructing 60 artificially damaged samples using the trained model.

Results: The PointFlow model effectively represented the diversity of anterior tooth shapes. The generated tooth shapes showed superior performance on multiple generative metrics compared to the reference dataset. In the reconstruction task, the model successfully recovered the missing regions in the damaged samples. The average Chamfer Distance for the missing regions across all damage types was 0.2738 ± 0.095 mm.

Conclusions: Deep generative models can effectively learn tooth characteristics and demonstrate potential in generating high-quality tooth shapes, suggesting their applicability for further clinical use.