Sleep‐related bruxism, microarousals and oxyhaemoglobin desaturations in sleep stages: A cross‐sectional study in a large apnoeic population

Background Sleep‐related bruxism (SB) is the habit of grinding or clenching the teeth during sleep, mediated by the non‐peripheral central nervous system. Purpose The objectives of this cross‐sectional study were to evaluate associations between SB, microarousals and oxyhaemoglobin desaturations and to compare the frequency of SB and microarousals in sleep stages, in an apnoeic population. Methods Two hundred and forty individuals composed the sample, who underwent a single full‐night polysomnography. Self‐reports and clinical inspections were not considered for assessing SB. The polysomnographic assessment of SB was performed using electrodes placed on masseter muscles and chin. SB was defined as more than two events of rhythmic masticatory muscle activity per hour of sleep. Microarousals were considered when there were abrupt changes in electroencephalogram frequencies, without complete awakening, lasting from 3 to 15 s. Oxyhaemoglobin desaturations were defined as significant drops (≥3%) in basal oxygen saturations. With these data, SB, microarousals and oxyhaemoglobin desaturations were evaluated and submitted to statistical analysis. Results Statistically significant differences were observed between bruxers and non‐bruxers when comparing the rates of microarousals (p