Several pathologies of the oral cavity have been associated with stress, so we investigated salivary-induced aggregation during psychological stress. In addition, salivary total protein, alpha-amylase, and secretory immunoglobulin A (s-IgA) were assessed. In this longitudinal study, 28 dental students provided unstimulated whole saliva during 10 minutes before an academic examination and subsequently 2 weeks and 6 weeks later in a nonstress situation. The effect of whole saliva on the aggregation of Streptococcus gordonii (HG 222) was determined spectrophotometrically. The results show a significant stress-mediated increase of salivary total protein concentration, alpha-amylase activity, amylase/protein ratio, alpha-amylase output, s-IgA concentration, and s-IgA output. There was also a trend for increased total protein output, whereas salivary flow rate was unchanged. The aggregation of S. gordonii in whole saliva collected before examination was 13.1%, whereas the aggregation in whole saliva collected during nonstress was 23.3%. This reduction was statistically significant (p <.01). Furthermore, the decrease in bacterial aggregation was related to the increase in state-anxiety (p <.05). The reduction in aggregation of S. gordonii under stress was not correlated with changes in salivary flow rate, s-IgA concentration, total protein concentration, or alpha-amylase activity. These results suggest that acute psychological stress exerts its influence on both salivary composition and salivary function. Reduced bacterial aggregation may be a contributing factor in the often reported relationship between stress and impaired oral health.
From the Departments of General Pathology and Internal Medicine (H.S.B.), Oral Biochemistry (J.A.B., T.J.M.L., A.V.N.A.), and Social Dentistry (J.H.), Academic Centre for Dentistry, ACTA, Amsterdam, The Netherlands, and Department of Psychonomics (B.B.), Faculty of Psychology, University of Amsterdam, Amsterdam, The Netherlands.
Address reprint requests to: H. S. Brand, PhD, Department of General Pathology and Internal Medicine, Academic Centre for Dentistry, ACTA, Louwesweg 1, 1066 EA Amsterdam, The Netherlands.
Received for publication February 22, 1995; revision received October 11, 1995.