On bruxing and breathing:The association between sleep bruxism and obstructive sleep apnea

Abstract

Obstructive sleep apnea (OSA) is a sleep breathing disorder that is characterized by full or partial collapse of the upper airway, normally resulting in oxygen desaturation and sleep arousal. It has been proven to be an independent risk factor for many systematic diseases, such as stroke and diabetes. Sleep bruxism (SB) is a masticatory muscle activity occurring during sleep that is manifested as clenching or grinding of teeth, possibly resulting in severe teeth wear, orofacial pain, and failure of dental repairment. Both OSA and SB are common sleep conditions. Studies reported that a large proportion of individuals with OSA were diagnosed with SB, suggesting a possible association between OSA and SB. This thesis aimed to 1) determine the essential number and type of jaw muscles for valid SB scoring in adults with OSA, 2) to investigate the prevalence and risk factors of SB in adults with OSA, 3) to identify the effects of OSA therapies on SB, and 4) to explore the underlying mechanism of the association between OSA and SB. By performing several polysomnographic studies, this thesis concluded that 1) valid SB scoring should be based on bilateral masseter and/or temporalis muscle EMG traces; 2) SB is a common comorbidity of OSA, especially in those with male gender and low body mass index; 3) the effects of OSA therapy on SB varies at an individual level; 4) the results of this thesis suggest that the associations between OSA and SB may have different patterns that vary between individuals