The causes of bruxism are divided into peripheral factors and central factors, occlusal factors are known to only play a minor role. Bruxism is associated with sleep micro-arousal and appears to be modulated by various neurotransmitters in the central nervous system. These neurotransmitters may be disturbed the balance between the direct and indirect pathways of the basal ganglia which are involved in the coordination of movements of masticatory muscle in bruxers. L-dopa, bromocriptine and propranolol can inhibit bruxism activity, botulinum toxin injections can reduce the frequency of bruxism events and decrease bruxism-induced pain levels, clonidine can inhibits the rapid eye movement(REM) of bruxism patients and the levels of catecholamines are higher in bruxers. Some authors think that bruxism patients with lower sleep efficiency, but some think that bruxism patients have normal sleep structure and quality; some people think that bruxism occurred more frequently in stage 2 and REM, some think bruxism episodes are equally distributed between non-rapid eye movement(NREM) and REM sleep, but some also think bruxism are mainly occurred in light sleep and seldom occurred in REM, moreover some think that bruxism is a abnormal oral activities that secondary to sleep micro-arousal. Psychological factors like personality and anxiety are also frequently mentioned in relation to bruxism. Bruxism patients have higher life stress and anxiety, the person that severe bruxism, their work and life pressure is more heavier. In this paper, A central factors of bruxism is reviewed in detail concerning their pathophysiological and psychosocial aspects.
