Bruxism is mainly regulated centrally, not peripherally

Abstract

Bruxism is a controversial phenomenon. Both its definition and the diagnostic procedure contribute to the fact that the literature about the aetiology of this disorder is difficult to interpret. There is, however, consensus about the multifactorial nature of the aetiology. Besides peripheral (morphological) factors, central (pathophysiological and psychological) factors can be distinguished. In the past, morphological factors, like occlusal discrepancies and the anatomy of the bony structures of the orofacial region, have been considered the main causative factors for bruxism. Nowadays, these factors play only a small role, if any. Recent focus is more on the pathophysiological factors. For example, bruxism has been suggested to be part of a sleep arousal response. In addition, bruxism appears to be modulated by various neurotransmitters in the central nervous system. More specifically, disturbances in the central dopaminergic system have been linked to bruxism. Further, factors like smoking, alcohol, drugs, diseases and trauma may be involved in the bruxism aetiology. Psychological factors like stress and personality are frequently mentioned in relation to bruxism as well. However, research to these factors comes to equivocal results and needs further attention. Taken all evidence together, bruxism appears to be mainly regulated centrally, not peripherally.

“Age is associated with self-reported sleep bruxism, independently of tooth loss.” A critical commentary

“…Within the methodological limitations of the study, the conclusion of Kato et al [1] was that self-reported SB is associated with age, independent of tooth loss. This result is in accord with the theory that SB is mainly centrally mediated, not peripherally [4]. The state of the art today is that despite the fact that the aetiology of sleep bruxism seems to be multifactorial (sleep homeostasis and arousal activity, oromotor excitability, psychological and personality traits, genetics, neurochemical activities, and oropharyngeal functions), there is no evidence of the role of occlusal or other morphological factors [7].The finding of the current study that the prevalence of SB decreased with age was in accordance to similar studies performed all over the world, but for the first time this association was not confounded by tooth loss [1].…”

“…It was believed that occlusal interferences cause a reflex-mediated activation of the elevator muscles through the stimulation of periodontal mechanoreceptors. Accordingly, the role of the bruxism activity is to eliminate occlusal interferences [4]. If this theory was true, bruxism must stop with dental loss.…”

Análise Perfilométrica do Padrão de Desgaste Dentário de Indivíduos Bruxômanos e sua Inter-Relação com a Erosão Dentária: Um Estudo Longitudinal

“…Com isso, para que fossem afastadas variáveis que pudessem influenciar o padrão de realização do hábito parafuncional em questão, as participantes deste estudo não deveriam apresentar qualquer tipo de doença sistêmica (LOBEZOO; NAEIJE, 2001) (como diabetes, artrite, fibromialgia e outras). Também foi restringido o uso das medicações tais quais inibidores seletivos da receptação de serotonina, catecolaminas, anfetaminas, dopaminas, cafeína, antidepressivos tricíclicos, fenilalanina, agonista da serotonina, antipsicóticos e ansiolíticos (como os Benzodiazepínicos), além de relaxantes musculares uma vez que algumas drogas, principalmente as que atuam no âmbito do Sistema Nervoso Central, são capazes tanto de exacerbar o bruxismo -quadro conhecido como distonia induzida por drogas, sendo este tipo de bruxismo uma desordem distinta do de origem idiopática (ORTEGA, 2009), quanto atenuar os quadros do mesmo (LOBEZOO;NAEIJE, 2001;ORTEGA, 2009). Como o desgaste dentário pode estar presente também durante a realização de tratamentos ortodônticos (GRECHI et al, 2008), contraindicou-se a realização conjunta com o período da pesquisa em questão, assim como terapia para DTM.…”

Conexões e caracterização neuroquímica de vias neurais envolvidas com o controle dos movimentos mandibulares

“…Among them, dopamine is of special interest since abnormal oral movements have been observed in complex disorders associated to dopamine imbalance [2]. Interestingly, oral movements seem to be influenced by dopamine receptors agonist or antagonist [2,24]. Oral dyskinesias [26,29], and possibly nocturnal bruxism, a motor dysfunction characterized by clenching or grinding of the dentition during sleep states [23], have been associated with dopaminergic dysfunction [24,34].…”

“…Interestingly, oral movements seem to be influenced by dopamine receptors agonist or antagonist [2,24]. Oral dyskinesias [26,29], and possibly nocturnal bruxism, a motor dysfunction characterized by clenching or grinding of the dentition during sleep states [23], have been associated with dopaminergic dysfunction [24,34]. Moreover, the consumption of drugs that alter dopaminergic transmission such as cocaine and amphetamine can cause intense tooth grinding in humans [3].…”