Abstract
Mouth guards or mouth pieces have been considered to be effective for preventing traumatic injury in the maxillofacial region. Influence of wearing these appliances on the stomatognathic system, however, have been little investigated. In this study, four volunteer adults were asked to wear two types of resilient mouth guard and one hard type maxillary full arch bite plane, to examine their influence on muscle activities (masseter and tempolaris) and maxillo-mandibular relation during maximum voluntary clenching.
The following results were obtained.
1. Wearing a resilient mouth guard caused an increase in masseter activities while a hard one caused a decrease in the temporal muscle in general, though a great deal of individual difference was observed.
2. Significant difference in mandibular positional change was not found between the two types of mouth guards with different resilience.
3. Close relation between muscle activities and changes in mandibular position, which could be explained by the static equilibrium system, was observed.
