The biofilm formation of the oral fungal pathogen Candida on denture acrylic strips coated with saliva, serum and, saliva-serum pellicle were examined in vitro using Candida albicans (four isolates), Candida glabrata (three isolates) and Candida tropicalis (three isolates). The degree of biofilm activity varied depending upon both the isolate and the pellicle. Significantly increased biofilm activity on the pellicle (particularly serum)-coated strips was observed with three isolates of C. albicans and another of C. glabrata on protein-coated acrylics, with increasing concentration of serum in the pellicle. Similar trends were observed with one isolate of C. albicans and C. glabrata, although the effects of pellicles were not significant. In contrast, with all three isolates of C. tropicalis and a single isolate of C. glabrata, although the biofilm activity on the protein-free control strips was significantly higher than that of saliva-coated strips, the increase in activity of pellicle-admixed biofilm depended upon the serum concentration. Candidal biofilm formation on acrylic surfaces is essentially promoted with increasing concentration of serum in the pellicle. This suggests that inflammation in the oral environment would facilitate fungal colonization on denture acrylic.

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The Japan Prosthodontics Society believes that identification of an umbrella term for occlusal discomfort might serve as a useful guide to formulating clinical practice guidelines in the future. This position paper represents summary findings in the literature combined with the results of a multicenter survey focused on dental occlusal treatment and the condition of patients who present with occlusal discomfort syndrome.

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-