Effects of dietary sucrose levels on pH fall and acid-anion profile in human dental plaque after a starch mouth-rinse.

The effects on the metabolism of starch by plaques formed in human subjects during periods of dietary sucrose limitation or supplementation were studied. High sucrose (HS) plaques showed lower resting pH and pH minima, and higher concentrations of lactate ion after the starch mouth-rinse than low sucrose (LS) plaques. Plaque samples incubated with starch solutions in vitro showed no differences in final pH or acid-anion concentrations between HS and LS diets. Plaque-amylase activity was higher on HS than LS diets. Thus starch was more acidogenic when consumed as part of a diet already rich in sucrose, but it is unclear whether this was a specific or non-specific effect of starch on plaque metabolism.