IADR Abstract Archives
Biochemical Salivary changes during the day, a clinical study.
Objectives: Biochemical composition of saliva may act as a protective factor against oral diseases, particularly dental caries. Daily fluctuations on the levels of some caries-related molecules have not been explored. The aim of this investigation was to explore circadian changes in the salivary concentration of several molecules, including nitrate, nitrite, glucose, lactate and ammonia in healthy young adults.
Methods: Fifteen mL of unstimulated saliva from 8 participants was collected at 6 time intervals during a day, from 7:00 am to 3:00 am, on the following day. Participants were provided with a standardized Mediterranean diet, calculated according to their nutritional requirements. Biochemical parameters in the saliva, including nitrate, nitrite, glucose, lactate and ammonia were measured (mg/L), using spectrophotometric test (Reflectoquant Flex, Merck). Differences were estimated with ANOVA at each time point.
Results: Nitrate, nitrite and glucose concentrations significantly varied during the day (p<0.05). Fasting (7:00 am) nitrate concentration was 22.2 mg/L and 70,8 mg/L at 3:00 pm. Nitrite increased from 1.9 mg/L at 7:00 am to 4,2 mg/L at 3:00 pm. Conversely, glucose decreased from 10.4 mg/L at 7:00 am to 4 mg/L, 4,1 mg/L and 3,4 mg/L at 3:00 pm, 7:00 pm and 11:00 pm, respectively. Lactate and ammonia remained stable throughout the day, without statistical significant differences (p>0.05).
Conclusions: Intrasubject variations were demonstrated in the concentrations of nitrate, nitrite and glucose, with differences between fasting and postprandial conditions. Biochemical properties of saliva seem to have circadian fluctuations. Further studies are needed to understand the implications in health and disease.
Methods: Fifteen mL of unstimulated saliva from 8 participants was collected at 6 time intervals during a day, from 7:00 am to 3:00 am, on the following day. Participants were provided with a standardized Mediterranean diet, calculated according to their nutritional requirements. Biochemical parameters in the saliva, including nitrate, nitrite, glucose, lactate and ammonia were measured (mg/L), using spectrophotometric test (Reflectoquant Flex, Merck). Differences were estimated with ANOVA at each time point.
Results: Nitrate, nitrite and glucose concentrations significantly varied during the day (p<0.05). Fasting (7:00 am) nitrate concentration was 22.2 mg/L and 70,8 mg/L at 3:00 pm. Nitrite increased from 1.9 mg/L at 7:00 am to 4,2 mg/L at 3:00 pm. Conversely, glucose decreased from 10.4 mg/L at 7:00 am to 4 mg/L, 4,1 mg/L and 3,4 mg/L at 3:00 pm, 7:00 pm and 11:00 pm, respectively. Lactate and ammonia remained stable throughout the day, without statistical significant differences (p>0.05).
Conclusions: Intrasubject variations were demonstrated in the concentrations of nitrate, nitrite and glucose, with differences between fasting and postprandial conditions. Biochemical properties of saliva seem to have circadian fluctuations. Further studies are needed to understand the implications in health and disease.