Combined analysis of shock absorption capability and force dispersion effect of mouthguard materials with different impact objects

Abstract

The aims of the present study were to investigate the shock absorption capability and force dispersion effect of mouthguard (MG) materials using load cell and film sensors. Two kinds of MG materials, ethylene vinyl acetate and polyolefin, were chosen for this study. When impact forces of approximately 5,000 N were applied on the MG materials using a round flat-nosed rod and a bluntly pointed rod, peak intensities were measured using the load cell sensor while peak stresses and impressed stress distribution areas were measured using the film sensor. Combined analysis using both load cell and film sensors clearly showed the shock absorption properties and force dispersion effects of different MG materials with different impact object shapes. Therefore, impact analysis involving a combined use of these sensor systems was useful and reliable in assessing the shock absorption capability and force dispersion effect of MG materials.

Present Status in Polymeric Mouthguards. A Future Area for Additive Manufacturing?

“…Compared with EVA, these polymers show higher tensile and tear strength with similar shock absorption capacity [92]. Additionally, polyolefins absorb less water from the oral cavity, which may prevent unwanted swelling, dimensional variations, or bacterial contamination of the protector [93,94]. In the case of mouthguards constituted by laminated sheets, polyolefins showed better interlayer adhesion than EVA sheets, which is essential to prevent the delamination of the device [66].…”

Appropriate fabrication method for vacuum‐formed mouthguards using polyolefin sheets

“…The vacuum‐forming process is commonly used because vacuum‐forming machines are easier to use and are more cost‐effective than pressure‐forming machines . For the thermoforming techniques, mouthguard sheet materials such as ethylene vinyl acetate or polyolefin have been used . Polyolefin shows satisfactory physical properties such as lower water absorption and better adhesive strength compared to ethylene vinyl acetate, and it has high shock‐absorbing capabilities that are similar to ethylene vinyl acetate .…”

Mouthguard sheet temperature after heating

“…Custom‐made mouthguards can be fabricated using thermoforming techniques (a vacuum‐forming process or a pressure‐forming process), an injection technique, or a packing technique . For the thermoforming techniques, mouthguard sheet materials such as ethylene vinyl acetate and polyolefin have been used commonly . Polyolefin exhibits satisfactory physical properties such as lower water absorption and better adhesive strength which is important when laminating the materials in comparison with ethylene vinyl acetate, and is suitable for use as mouthguard material .…”