Mechanical properties of 3D printed mouthguards: Influence of layer height and device thickness

Mouthguards are polymeric devices recommended to be used by athletes to help prevent orofacial injuries. Some of the problems described by the athleteswhen using themouthguards can be addressed by producing customized devices with thinner walls by additive processing techniques. In the present work, new polymericmaterials for this application, such as poly(lactic acid) (rPLA) recycled from food packaging, poly(methyl methacrylate) (PMMA), high impact polystyrene (HIPS), and thermoplastic polyurethane (TPU), are proposed for the preparation of protective mouthguards, in alternative to the ethylene-vinyl acetate (EVA) copolymer, the current gold standard. Specimens were printed with two different thicknesses (2 mm and 4mm) to study their influence on the final properties of the printed samples. The characterization included chemical, thermal, surface, and mechanical aspects of commercially acquired polymeric filaments and printed components. All the studied materials showed a decrease in the impact strength with increasing specimen thickness, except for TPU due to its highest deformation capacity. Compared with EVA, TPU has a similar energy absorption, while the other polymers presented higher values