Hardness and shock absorption of silicone rubber for mouth guards

Silicone rubbers have general properties that make them suitable for the fabrication of custom-made mouth guards. This study evaluated the shock absorption properties and Shore A hardness of several silicone rubbers and derived products, compared their values with those of materials commonly used for the manufacture of mouth guards, and correlated the shock absorption and transmission abilities of these different materials with their Shore hardness. Silicone rubbers absorb shock better than the materials currently used for custom-made mouth guards. In addition, to adapt mouth guards to particular sports, the properties of the silicone rubbers can be appropriately modified by the addition of oils or glass fiber reinforcement. Statistical analysis of hardness values and transmitted forces for the 27 materials tested indicates that the maximum transmitted force increases with hardness. However, this relationship is not linear, and departure from linearity is greatest for minimal and maximal hardness values.