Study of the Effect of Different Sour Stimulus Concentrations and Circadian Rhythm on Salivary Volume by the Modified Ion Dilution Method

In the current study, we used the modified ion dilution method to evaluate the influence of the circadian rhythm on the salivary volume in response to varying sour concentrations. We found that the salivary volume changed depending on when the sample was taken and on the sour concentration. Specifically, there was a definite trend for the salivary volume to be low in the morning and to increase from around lunchtime to evening. In addition, the influence of the circadian rhythm on salivary volume tended to be reduced by a strong taste stimulation (high sour concentration). These results suggest that the greater the amount of stimulation (sour stimulation), the smaller the effect of circadian rhythm on the salivary volume.