Multi-Material 3D Printing of a Customized Sports Mouth Guard: Proof-of-Concept Clinical Case

Abstract

A multilayer mouth guard is known to have the best protective performance. However, its manufacturing in a digital workflow may be challenging with regards to virtual design and materialization. The present case demonstrates a pathway to fabricate a multilayer individualized mouth guard in a fully digital workflow, which starts with intraoral scanning. A free-form CAD software was used for the virtual design. Two various CAM techniques were used, including Polyjet 3D printing of rubber-like soft material and silicone printing using Drop-on-Demand technique. For both methods the outer layer was manufactured from more rigid materials to facilitate its protective function; the inner layer was printed from a softer material to aid a better adaptation to mucosa and teeth. Both 3D printed multilayer mouth guards showed a clinically acceptable fit and were met with patient appraisal. Their protective capacities must be evaluated in further clinical studies.

Keywords: additive manufacturing; bite guard; dentistry; intraoral scanning; polyvinylsiloxane printing; rapid manufacturing; sports medicine.

Figure 1

The fixed OVD with a wax plate and Aluwax from the frontal (A) and side aspects (B).

Figure 2

The digital impression of both dental arches with the fixed OVD.

Figure 3

Virtual blocking of anatomical undercuts with the “virtual clay tool” in the Zbrush software.

Figure 4

Design of the inner layer (red) (2 mm) using “inflat” tool in the Zbrush software.

Figure 5

(A) Inner layer (blue) and outer layer (transparent) with virtual polishing of the outer surface; (B) adaptation of the caudal part to the occlusal surface of the lower jaw and airway creation.

Figure 6

(A) The Polyjet printed soft multilayer MG. (B) The ACEO silicone printed soft multilayer MG.

Figure 7

The Polyjet printed multi-material MG in situ, showing a good adaptation to the soft tissue and lower dental arch from the frontal (A) and side aspects (B). The slit in the middle part shall ensure the air supply, when the teeth are clinched. The outer surface is of micro roughness which may irritate the soft tissues within a short wearing period and calls for further postprocessing.

Figure 8

The Drop-on-Demand printed multi-material MG in situ, showing a good adaptation to the soft tissue and lower dental arch from the frontal (A) and side aspects (B). The staircase effect leaves a macro roughness which is expected to harm the soft tissue over a short wearing period and therefore should be further post-processed.