AbstractSleep bruxism (SB) is a repetitive jaw muscle activity with clenching or grinding of the teeth during sleep. SB is characterized by what is known as rhythmic masticatory muscle activity (RMMA). RMMA is the laboratory polysomnographic finding that differentiates SB from other oromandibular movements seen during sleep. Most often RMMA episodes are associated with sleep arousal. Some patients will report similar complaints related to both SB and sleep disordered breathing (SDB). There are some reports that would suggest that SB is a result of SDB. It has has been postulated that SB is a compensatory mechanism to re establish muscle tone of the upper airway. While these disorders do in fact often present concomitantly, the relationship between the two is yet to be fully elucidated. This Critical Appraisal reviews 3 recent publications with the intent to better define what relationships may exists between SDB and SB. While the current evidence appears to support the notion that these are often concomitant disorders, it also makes clear that evidence to support the hypothesis that SDB is causative for SB is currently lacking. (J Esthet Restor Dent 00:000–000, 2016)