Abstract
The effect of sucrose intake versus a sucrose-free diet containing glucose on microscopic and viable counts of microorganisms in 0-3 d dental plaque formed on the buccal surface of a lower premolar was studied in six subjects. The acidogenic potential of 7 d dental plaque, as well as secretion rate, buffer capacity and pH of stimulated saliva, were estimated. Direct counts of microorganisms were higher in 2 and 3 d plaque formed on a sucrose-containing diet compared to plaque on a sucrose-free diet. Microaerophilic incubation yielded higher recoveries of microorganisms than anaerobic incubation. Sucrose intake was associated with relatively low viable counts at the start of plaque formation and relatively high counts in 2 and 3 d plaque. Viable counts of haemophili showed the same pattern at a much lower level. In the 12 h samples all viable counts were lower than all microscopic direct counts of units consisting of one or more microorganisms. During the remaining experimental period, viable counts from plaque formed on the sucrose-containing diet approached the level of direct counts of units faster than those obtained from the sucrose-free diet. Sucrose intake increased the acidogenic potential in dental plaque and removal of sucrose from the diet caused an increase in secretion rate of saliva.