Effect of Photo-Acoustic Stimulation Patterns on Human Whole Saliva Secretion

Objectives: Previous studies indicated significant effect of mixed photo-acoustic stimulation on human salivary secretion. The aim of this pilot study was to investigate if administration of specific photo-acoustic stimulation patterns have pattern specific effect on saliva secretion, and whether it is coupled to phenomenological effects or not. Methods: Six healthy volunteers without any oral pathologies participated (male: 3, female 3, age: 23-27 yrs). Four patterns of stimulation frequency were studied within a range of 1-15Hz such as increasing pattern; decreasing pattern; increase followed by decrease and decrease followed by increase. Experiments were repeated four times in a self control design. Whole saliva was collected in 5min phases before the stimulation as control value, under administration of specific patterns, under post stimulation phases and after the experiment as last value. The volume of saliva was measured, the flow rate was calculated. Total protein (Bradford) and amylase (starch split) concentration of samples were determined (after 10.000g 4°C 10min). Phenomenological parameters were measured with numerical analogue scales. Results: Flow rate, protein- and amylase outputs decreased and protein concentration increased significantly (p≤0.05, Friedman ANOVA, Wilcoxon test) and amylase concentration did not change during stimulation phases. Flow rate, protein concentration, protein- and amylase outputs increased significantly (p≤0.05, Friedman ANOVA, Wilcoxon) and amylase concentration did not change during post stimulation phases. Protein and amylase concentrations, protein- and amylase outputs were significantly higher (p≤ 0.05, Wilcoxon test) also in the last value comparing to control. Pattern-specific effects were: differences of amylase output and phenomenology during stimulation, protein concentration and output in post stimulation phases (p≤0.05, Wilcoxon test). Conclusion: Our data indicate significant effect of photo-acoustic stimulation on saliva secretion. A specific effect on certain salivary parameters and phenomenology may not be excluded. Salivary and phenomenological effects seem to be rather independent. This research was supported by TÁMOP-4.2.1/B-09/1/KMR-2010-0001.