Effect of increasing sucrose concentrations on oral lactic acid production

Oral lactic acid production was studied on 11 healthy dental student volunteers (5 males and 6 females) during clearance of five solutions containing 5, 10, 15, 20 and 30% of sucrose. Oral fluid samples were collected at times zero, immediately before taking the sucrose solutions ('baseline'), and 15 min following intake of the solutions. The samples were analyzed qualitatively and quantitatively for the presence of lactic acid and remaining sugars using high-performance liquid chromatography (HPLC). Results indicate that the amount of lactic acid in oral fluid significantly increased with increasing sucrose concentrations, up to 15% sucrose. With the higher sucrose concentrations (20 and 30%) equivalent or lower amounts of lactic acid were obtained. The threshold level for maximum lactic acid production was found to be between 10 and 15% sucrose. Statistical analysis of the data (Student's t test) indicated a significant difference in lactic acid production between the 5 and 10% sucrose solutions versus the 15, 20 and 30% sucrose solutions tested (p < 0.05). Clinical Significance: Ingestion of solutions with higher sucrose concentrations (>15%) produced similar amounts or less of lactic acid during oral clearance than solutions containing lower sucrose concentrations (<15%).