Oral parafunctions and positive clinical examination findings

Oral parafunctional activity can be fatigued and painful masticatory muscles and/or pain in the temporomandibular joints. There is controversial discussion in the literature as to what role parafunctional activity plays in the multi-causal pathologic process.

The purpose of this study was to determine any association between the level of parafunctional habits versus the level of mandibular dysfunction and to test the hypothesis that TMD/bruxer patients have significantly increased muscle tension and joint pain.

There were 307 subjects (140 males und 167 females) selected for this investigation. 299 subjects were examined regarding any relationships between clenching and the incidence of muscle sensitivity. The age of subjects ranged from 20 to 54 years old, with a mean age of 35.4. 114 subjects had at least one sign of temporomandibular disorders (tenderness/pain on palpation of the joints or muscles, TMJ sounds, pain or deviation during maximum mouth opening (active/passive).

81 subjects admitted to clenching, while 218 said they did not. Among the "non-clenchers", 68.8% had no sensitive muscles, 31.2% indicated sensitive masticatory muscles. Those who clenched their teeth were distributed as follows: 53.1% were diagnosed with bilateral masticatory muscle sensitivity, 46.9% showed no such indications. The two groups were not homogeneously divided, with regard to pain/discomfort (p = 0.001; Fisher's precision test).

This study found a statistically solid relationship between the incidence of "clenching" and muscle palpation findings, as well as between sensitivity in the mandibular joints from lateral and to cranial and dorsal with positive muscle palpation findings. The agreement between sensitivity of the masticatory musculature and the mandibular joint demonstrates that intensive clenching can predominantly lead to pathologic phenomena in the muscles or joints.