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Notes: Abstract. 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 crossover 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.

Notes: Aims: A single centre, randomised single-blind, three-way crossover study was performed, to compare the effect of an experimental test toothpaste with a commercially available whitening toothpaste and water control at inhibiting extrinsic stain promoted by repeated chlorhexidine/tea rinses.Methods: This study used 23 subjects. During the week before the study the subjects received a prophylaxis to remove all staining, plaque and calculus deposits. On the Monday of the following week subjects returned to the clinic to receive their rinses and to check their dentition was stain free. Under direct supervision at both 09:00 and 13:00 hours they rinsed with either a toothpaste slurry or water control that was repeated daily up to and including the following Thursday. Additionally from the Monday to the Thursday each subject rinsed with a 0.2% chlorhexidine mouthrinse, immediately followed by a rinse with a warm black tea solution. This cycle was repeated hourly eight times throughout the day and on the following days until the Friday. Throughout this period volunteers omitted all other forms of oral hygiene except rinsing with the chlorhexidine mouthwash. On the Friday the level of stain on the teeth and dorsum of tongue was assessed using the Lobene stain index for both stain area and intensity. At the end of each trial period each subject received a thorough prophylaxis to remove all plaque, calculus and staining before starting the second and third period of the study.Results: As expected appreciable amounts of extrinsic stain accumulated on the teeth over each study period. The amount of stain following use of the toothpastes and water control was least with the experimental toothpaste, followed by water control and lastly the commercial whitening paste. For all sites combined there was evidence that the experimental paste was significantly superior to both the commercial paste and water control at reducing stain area (p〈0.001), a product of stain area and intensity (p〈0.001 and 0.05, respectively) but not stain intensity (p〉0.05).Conclusions: In this stain-prevention model the use of an experimental paste showed a significant reduction in stain accumulation on the teeth compared with a (placebo) negative water control and a commercially available whitening paste. As such the experimental paste would be expected to be of benefit in controlling extrinsic dental staining.