Computer-Aided Design of Personalized Occlusal Positioning Splints Using Multimodal 3D Data

TL;DR

This work tackles the problem of reliably designing occlusal positioning splints that reproduce a clinician-defined mandibular position using multimodal 3D data. It introduces an end-to-end, fully digital workflow in which the splint is a physical realization of a rigid-body transformation, represented by a transformation matrix, and employs a novel virtual embossing mechanism to resolve surface conflicts. The approach integrates intraoral scans, CBCT, and 3D facial data, and provides an open-source plugin (Splint-maker) to enable rapid, reproducible fabrication. Validation on a single volunteer demonstrates sub-millimeter accuracy across multiple metrics, establishing a transparent foundation for future clinical validation and application in multimodal image registration and CR/MI discrepancy quantification.

Abstract

Digital technology plays a crucial role in designing customized medical devices, such as occlusal splints, commonly used in the management of disorders of the stomatognathic system. This methodological proof-of-concept study presents a computer-aided approach for designing and evaluating occlusal positioning splints. The primary aim is to demonstrate the feasibility and geometric accuracy of the proposed method at the preclinical stage. In this approach, a three-dimensional splint is generated using a transformation matrix to represent the therapeutic mandibular position. An experienced operator defines this position using a virtual patient model reconstructed from intraoral scans, CBCT, 3D facial scans, and a digitized plaster model. We introduce a novel method for generating splints that reproduces occlusal conditions in the therapeutic position and resolves surface conflicts through virtual embossing. The process for obtaining transformation matrices using dental tools and intraoral devices commonly employed in dental and laboratory workflows is described, and the geometric accuracy of both designed and printed splints is evaluated using profile and surface deviation analysis. The method supports reproducible, patient-specific splint fabrication and provides a transparent foundation for future validation studies, supporting multimodal image registration and quantification of occlusal discrepancies in research settings.

Figures (22)

• Figure 1: From the left: 1. Maxilla and mandible in maximum intercuspation. 2. The therapeutic position of the mandible, 3. Virtual movement of the occlusal surface into the therapeutic position. 4. a splint built joining the surface of maxilla teeth and moved occlusion surfaces.
• Figure 2: Concept of the positioning splint: on the left: cross-sections of the upper and lower teeth shown in black, the occlusal surface in red, the inner (tooth-adapted) surface in blue, and the minimum thickness boundary (external surface) in green, on the right the resulting occlusal splint shown in red between the upper and lower teeth in black.
• Figure 3: Occlusal splints for different displacements from the occlusal plane; the green line indicates the minimum splint thickness, and the red line marks the target therapeutic position (TP).
• Figure 4: From the left: 1. External surface without surfaces shadowed by the occlusion in therapeutic position 2. External and occlusal surfaces together 3. Cross-section of the splint with the upper teeth
• Figure 5: Left: Profiles of the upper and lower teeth in maximal intercuspation (MI) and in the therapeutic position (TP); Right: the splint profile (blue) between the upper (red) and lower (green) teeth, with the cross-section taken through the upper teeth.