Evaluation of stress biomarkers and electrolytes in saliva of patients undergoing fixed orthodontic treatment.

BACKGROUND: The aim of this study was to test the hypothesis that treatment with orthodontic appliances evokes significant functional limitations and emotional stress, which can be detected by salivary biomarkers. METHODS: Twenty subjects (10 men and 10 women) who underwent orthodontic treatment were included in this prospective study. Saliva was sampled for detection of alpha-amylase activity and cortisol levels at three different times: before bracket placement (T0), 24 hours after archwire placement (T1), and 30 days after archwire placement (T2). The saliva electrolytes concentrations of calcium, phosphorus, magnesium, sodium and potassium were also evaluated. Moreover, the possible functional limitations of the appliances were evaluated by a masticatory performance test and pain experience registration. All variables were compared with those in a control group with normal occlusion. RESULTS: The orthodontic patients exhibited a significant increase in emotional stress as detected by the alpha-amylase activity at T1, the period in which patients reported the higher values of pain and exhibited the lower masticatory performance indices. The basal salivary cortisol was not affect by the treatment and the main change detected in electrolyte concentration was a sodium reduction, when these patients were compared to controls. CONCLUSIONS: The present data indicate that orthodontic patients are under emotional stress only during the period of higher pain experience, which could also disrupt the masticatory performance. However, these alterations were not correlated with a single measurement of stress-related biomarkers in saliva, suggesting that these solitary endocrine measurements are not adequate to predict the temporary pain and masticatory limitation experimented by patients undergoing orthodontic treatment.

How may stressful experiences contribute to the development of temporomandibular disorders?

Temporomandibular disorders (TMD) comprise the most common cause of chronic facial pain conditions, and they are often associated with somatic and psychological complaints including fatigue, sleep disturbances, anxiety, and depression. For many health professionals, the subjectivity of pain experience is frequently neglected even when the clinic does not find any plausible biologic explanation for the pain. This strictly biomedical vision of pain cannot be justified scientifically. The purpose of this study is to demonstrate, by original articles from the literature and recent studies conducted in our own laboratory, the biological processes by which psychological stress can be translated into the sensation of pain and contribute to the development of TMD. The role of the hypothalamic-pituitary-adrenal axis, the serotoninergic and opioid systems in the pathogenesis of facial pain is exposed, including possible future therapeutic approaches. It is hoped that knowledge from apparently disparate fields of dentistry, integrated into a multidisciplinary clinical approach to TMD, will improve diagnosis and treatment for this condition through a clinical practice supported by scientific knowledge.