Influence of Mouthguard Characteristics on Biomechanical Response to Simulated Impact

Objectives: The purpose of this study was to evaluate the influence of different type and thickness of mouthguard on stress distribution generated in the skull, teeth and jaw as a consequence of a direct physical impact.
Methods: A complete human skull was modeled (TMJ, jaw, teeth and respective alveolus) using a software CAD (Rhinoceros 5.0). Two types of mouthguard (C:customized and S:stock) with three different thicknesses (1, 2 and 4mm) were designed at the complete model, and no protection as control. Seven situations were simulated in two conditions, open (O) and close (C) mouth. The fourteen geometries were exported to CAE software (Ansys 17.0), all materials were considered isotropic, homogeneous and linearly elastic. The skull base was fixed at foramen magnum and the loading (500N) was applied on the canine tooth simulating a ball impact. Nonlinear mechanic structural analyses were loaded to all models and the Maximum principal (MPa) and Von-Mises stresses were used as failure criteria.
Results: The control group (no protection), showed higher stress peak concentration caused more damage to the opened than to closed mouth. The presence of a mouthguard significantly reduced the generated stress in all structures, and the customized/individualized type was more efficient than stock. The thicker mouthguard resulted in lower stress concentration, independently of type.

Conclusions: Mouthguards are beneficial and assist in damping the generated stress. Customized mouthguards are more effective for preventing trauma during at-risk activities of impact. The thicker the device, the greater the protective capacity. When it is impossible to use a mouthguard, keeping the teeth in maximum intercuspal position is less harmful.