Does sleep bruxism serve a physiological purpose?

The Effect of Severity of Obstructive Sleep Apnea on Sleep Bruxism in Respiratory Polygraphy Study

“…As we know from the human experimental model by Carra et al, sleep instability and arousal are suspected to be a permissive window for SB activity in predisposed individuals [ 9 ]. It was also previously hypothesized that rhythmic masticatory muscle activity is an autonomic reflex that may support the cerebral blood supply [ 10 ]. In some cases, the apnea could be interrupted by a contraction of the masseter muscles following arousal.…”

“…Most SB episodes occur during cortical arousal associated with an increase in heart rate [ 34 ]. It has also been reported that preceding sleep deprivation and beta-blockers influence the BEI index in bruxers [ 10 ]. The homeostatic imbalance of the autonomic nervous system related to arousal during sleep constitutes the starting point for the cardiovascular implications of sleep bruxism.…”

“…In many cases, they may appear concomitantly. There were attempts devoted to assessing the relationship between OSA and sleep bruxism (SB), but data are limited and inconsistent [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. However, Wieckiewicz et al aimed to study the association of selected single-nucleotide polymorphisms (SNPs) occurring within the genes of the serotonin and dopamine pathways in individuals with SB and OSA [ 12 ].…”

“…Since pathophysiological data on SB are lacking [ 20 ], an investigation to clarify the nature of the relationship between SB and OSA may be necessary. Some studies on a few groups have failed to confirm the SB and OSA causative connection [ 7 , 8 ]; however, recently, the correlation has been demonstrated [ 9 , 10 , 11 ]. OSA has also been considered a new risk factor for SB, together with emotional stress, the consumption of tobacco, alcohol or coffee and anxiety disorders, which we recently confirmed [ 6 , 21 , 22 , 23 ].…”