Bruxism secondary to chronic antidopaminergic drug exposure.

Eight cases of diurnal bruxism (DB) secondary to long-term antidopaminergic drug exposure are reported. Five exhibited a grinding pattern, one a clenching form, and two a mixed type. An odontological etiology was absent throughout. EMG recordings disclosed two distinct patterns of muscle activity, one with brief rhythmic, forceful contractions and the other featuring sustained prolonged contractions. Surface EMG and EEG monitoring during a 24-h period confirmed the absence of bruxism during sleep. Several drug trials failed to provide relief. Our findings support DB as a focal tardive dystonia syndrome.