A 24-h regrowth study to evaluate the plaque inhibitory properties of a proprietary liquid dentifrice

Dentifrices have typically been formulated as pastes. Recently however, a number of liquid products have become available. The chemical plaque inhibitory activity of such products has so far received little attention. The aim of this study was to determine the plaque inhibitory effect of a proprietary liquid dentifrice by comparison to a negative control (water) and a conventional fluoride toothpaste. The study design was a randomised single centre, single blind 3-way cross-over trial with the objective of validating claims of plaque inhibition for the liquid dentifrice. Volunteers were rendered plaque free then asked to brush for one minute with one of the three test products, following which they abstained from oral hygiene for the subsequent 24 h. The plaque area was recorded and then measured planimetrically. The results showed that more plaque accumulated with water and the liquid dentifrice compared with the fluoride toothpaste. Thus, there was a statistically significant difference between the fluoride toothpaste and water and between the fluoride toothpaste and the liquid dentifrice. There was no significant difference between the liquid dentifrice and water. It is concluded that in this particular model system, the liquid dentifrice provided little chemical plaque inhibitory action.