[Experimental studies on properties of mouth protector: evaluation of various materials dynamic energy absorption test with electrical shock sensor].

During contact sports, mouth protectors are very effective in protecting teeth from traumatic forces, which are usually great enough to fracture teeth or at least to damage their supporting structures. In addition, they reduce the force transmitted through the temporomandibular joint to the base of the skull. Athletes select mouth protectors from various view points, that is, energy absorption, comfortable seating, retention, durability, speech facility, lack of taste, and cleanliness. In this study, the physical properties of various highly polymerized compound materials were investigated in an attempt to select a suitable material for use as a mouth protector and to develop a new relevant mechanical test. Dynamic energy absorption tests were performed by positioning a specimen on the board and allowing a 12.7 mm diameter steel ball to fall from a predetermined height and measuring by electrical shock sensor. The following results were obtained: 1. Materials such as Rabaron S 371 C, Exaflex, Flexicon and Sorbosene (soft type), indicated highest value of energy absorption rate. 2. As the thickness of inner materials increased the energy absorption rate also increased and the logarithmic decrement decreased.