Association between sleep bruxism and stress sensitivity in an experimental psychological stress task

Abstract

The objective of this study was to examine the association between sleep bruxism and psychological stress. The subjects consisted of 76 volunteers, who were divided into those with and without bruxism according to the diagnostic criteria for sleep bruxism outlined by the American Academy of Sleep Medicine (AASM). Stress sensitivity was evaluated before and after an experimental stress task, which involved simple mathematical calculations. It was assessed objectively by measuring the subjects' salivary chromogranin A (CgA) levels and subjectively using a ten-division visual analog scale (VAS). Compared with those observed before the stress task, the mean salivary CgA levels of the non-bruxism group (n = 54) were not significantly increased after the stress task. Conversely, the mean salivary CgA levels of the bruxism group (n = 22) were significantly increased after the stress task (P < 0.01). The mean VAS scores of the groups without (n = 54) and with (n = 22) bruxism were significantly (P < 0.01) increased after the stress task compared with those observed before the stress task, but no differences were detected between the two groups in the stress task. These findings suggest that there is an association between sleep bruxism and psychological stress sensitivity.Oral habits such as bruxism are thought to affect temporomandibular disorders (TMD) and might have a relatively strong effect on the durability of prosthetic appliances (20,30). Bruxism, which is defined as clenching or grinding of the teeth, or a combination of both, is a diurnal or nocturnal parafunctional activity and has long been regarded as requiring treatment (5). It is thought that bruxism is associated with psychological stress (1,2,8,10,22). On the other hand, some studies did not find any association between bruxism and stress (15,19). The following reasons might explain this disagreement. In most of the above studies, diurnal bruxism and sleep bruxism were not distinguished from each other, and there were variations in the methods used to evaluate oral habits. In addition, differing definitions of stress and various methods for assessing stress were employed in these studies (17). Also, in these studies, stress was evaluated subjectively, such as by self-reporting, questionnaires, etc. Thus, the relationship between bruxism and stress is much more complex than previously imagined and involves many psychosocial factors (17). When humans are exposed to psychological stressors, the hypothalamic-pituitary-adrenal (HPA) axis and the sympathoadrenal medullary (SAM) system are activated (9,13,26). This results in changes of biomarkers, e.g., cortisol and/or chromogranin, etc., being secreted into the serum or saliva. Therefore, stress can be objectively evaluated by analyz-

The psychology of tooth wear

“…Psychosocial job stress, low social support from supervisors or colleagues and high‐depressive symptoms demonstrated a significantly increased risk of bruxism in a study involving 2680 participants . These findings tend to agree with those of other studies demonstrating a significant association between tooth wear, depression, stress, and emotional stability …”

Psychosocial Aspects of Bruxism: The Most Paramount Factor Influencing Teeth Grinding

“…The main role in the tension coordination belongs to gamma neurons, which are controlled by higher centers and participate in the development of an abnormal muscle activity (Figure 1) [17]. Chronic stress and warning reactions triggered by it manifest themselves as functional deficiencies of the nervous-muscle system and are the main etiologic factors of psycho-dependent bruxism [41]. When these disturbances appear, attention is drawn by venting the accumulated tensions directly through the dental arches, by means of increased muscle activity, which may lead to headaches.…”

Association of gender, oral habits, and poor sleep quality with possible sleep bruxism in schoolchildren

“…Some studies have evaluate children's behavior and demonstrated that psychological and emotional aspects, such as anxiety, aggressiveness, and hyperactivity, have been associated with possible sleep bruxism. 31,32,33 Recently, this theory has been challenged, since bruxism originates from the central nervous system, so this association would be more related to awake bruxism. Therefore, these results are consistent with those of other studies carried out with adults and children.…”