Salivary glucose concentration and daily variation in the oral fluid of healthy patients

Abstract

The aim of this study was to determine the concentration and the variations of salivary glucose in healthy patients who were sampled at five different intervals during the day. Samples of un-stimulated saliva have been collected from 21 healthy patients using the drooling technique and they were divided into two categories. In the first category, patients were asked not to toothbrush their teeth in the 8 hours prior to collection of the salivary sample. Patients in the second category were instead asked to toothbrush 90 minutes before the collection of the first sample of saliva. The glucose concentration was measured in all patients via an enzymatic spectrophotometry. Patients have been selected following a strict inclusion criteria, which included <5% of plaque presence e according to the plaque Index and a total absence of oral disease that could possibly interfere with sample taking or oral fluid analysis. The average age of patients was 22,4±2,6 years old of which 45% were female and 55% were male. Samples were collected five times between 8 am and 12 pm, before and after breakfast. Data was statistically analyzed using the Skewness/Kurtosis Test, Shapiro-Wilk Test, Kruskal Wallis Test and Linear Regression Model, considering values of p<0,05 to be significant. The average rate of un-stimulated salivary flow was 0,53±0,21 ml/min. There were no significant differences between salivary glucose values and salivary flow in female and male patients. However, we observed a typical trend which recurred for each patient and resembled a "pseudo-glycemic curve". The collected data suggests that glucose concentration results did not show statistically significant differences (p>0,078) which could however be due to the little number of patients assessed, nonetheless there is a trend, recalling a "pseudo-glycemic curve" not referable to changes in flow rates, probably due to glucose catabolism and shunt.