Bruxism and stress relief

Abstract

The masticatory organ, originally developed as a branchial system, has evolved over a long period of geological time through a stage in which it was predominantly a tool for expressing aggression into an organ for emotional management. In humans, the strong grinding and clenching function of the masticatory muscles, known as bruxism, plays a role in mitigating stress-induced psychosomatic disorders by down-regulating the limbic system, the autonomic nervous system, and the hypothalamic-pituitary-adrenal (HPA) axis. Experimental research results showed that bruxism-like activity (BLA) has beneficial effects on stress-induced reactions, such as increased expression of Fos, neuronal nitric oxide synthase (nNOS), dual phosphorylated extracellular signal-regulated kinase (pERK1/2), corticotropin-releasing factor (CRF), and free radicals in the paraventricular nucleus (PVN) of the hypothalamus. It has also been shown to cause alterations in the blood neutrophil/lymphocyte ratio, adrenocorticotropic hormone (ACTH) level, and stomach ulcer formation in animals studies and has increased amygdala neuronal activity and salivary chromogranin A level in human studies. These findings strongly suggested that parafunctional activity of the masticatory organ-aggressive BLA behavior-has the ability to decrease stress-induced allostatic overload. The health of the masticatory organ depends critically on occlusion, which must be of sufficient quality to carry out its important role in managing stress successfully. Occlusion and the brain must function in harmony. For these reasons, we must integrate the study of occlusion into the broader scope of medical science; in so doing, we can meaningfully advance the state of the art of dental care and general health care.