Effect of sucrose rinses on the oral microflora and on salivary sucrase activity

The effect of sucrose rinses on the salivary microflora and on bacterial sucrose cleaving, i.e., sucrase activity, was studied in 11 dental students with high salivary counts of mutans streptococci (> or = 10(5) CFU/ml). The subjects rinsed for 1 min with a 10% (w/v) sucrose solution every 4-h during waking hours on 2 consecutive days. Four paraffin-stimulated saliva samples were collected as follows: one before the rinses and then 12 h and 5 and 8 days after the rinses. Commercial dip-slide methods were used to determine viable counts of mutans streptococci, lactobacilli, and yeasts; mutans streptococci were also enumerated using MSB agar, while blood agar was used to recover the total facultative and anaerobic bacteria. The sucrase activity was determined using both whole (mainly cell-associated) and centrifuged (extracellular) saliva samples. The proportions of facultative bacteria (p = 0.007) and mutans streptococci (p = 0.001) increased as a result of the sucrose rinses. No changes were detected in the number of lactobacilli or yeasts. The sucrose rinses increased both the cell-associated (p = 0.049) and the extracellular (p = 0.011) sucrase activities. The measurement of sucrase activity may be of value in assessing dietary habits and sucrose consumption.