Quantitative study of bite force during sleep associated bruxism

Nocturnal bite force during sleep associated bruxism was measured in 10 sub jects. Hard acrylic dental appliances were fabricated for the upper and low er dentitions of each subject. Miniature strain-gauge transducers were moun ted to the upper dental appliance at the right and left first molar regions . In addition, thin metal plates that contact the strain-gauge transducers were attached to the lower dental appliance. After a 1-week familiarization with the appliances, nocturnal bite force was measured for three nights at the home of each subject. From the 30 recordings, 499 bruxism events that met the definition criteria were selected. The above described system was a lso used to measure the maximum voluntary bite forces during the daytime. T he mean amplitude of detected bruxism events was 22.5 kgf (s.d. 13.0 kgf) a nd the mean duration was 7.1 s (s.d. 5.3 s). The highest amplitude of noctu rnal bite force in individual subjects was 42.3 kgf (15.6-81.2 kgf). Maximu m voluntary bite force during the daytime was 79.0 kgf (51.8-99.7 kgf) and the mean ratio of nocturnal/daytime maximum bite force was 53.1% (17.3-111. 6%). These data indicate that nocturnal bite force during bruxism can excee d the amplitude of maximum voluntary bite force during the daytime.