Clinical studies to determine the effectiveness of a whitening toothpaste at reducing stain (using a forced stain...

Two single centre, randomized single-blind, crossover studies were performed, to compare the effect of a test toothpaste with a conventional fluoride paste in the inhibition and removal of extrinsic dental stain promoted by repeated chlorhexidine/tea rinses.

These studies used 24 subjects in each of two separate clinical trials. On the Friday before each trial period, the subjects received a prophylaxis to remove all staining, plaque and calculus deposits. On the following Monday, subjects were checked whether they were stain free and then under direct supervision they 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. In addition subjects also received daily a single toothpaste slurry rinse or control water rinse in the morning and lunchtime. No other form of oral hygiene was permitted during this period. On the Friday, both stain area and intensity was assessed using the Lobene Stain Index. For the stain removal study, stain was promoted again using chlorhexidine and tea rinses. After 4 days, stain was measured both prior to and immediately after brushing with the allocated toothpaste for 2 min. Subjects were then instructed to use the toothbrush at home according to their normal oral hygiene practices. On the following Wednesday, the amount of stain present was re-assessed. Each subject subsequently received a thorough prophylaxis to remove all plaque calculus and staining before starting the following periods of the study.

The study showed no difference in the ability of the test whitening toothpaste, control toothpaste and water control at inhibiting stain. There was also only a small difference (3.5% for product of area and intensity) between the ability of the two toothpastes to help remove stain after a single brushing. The difference was however in favour of the test product which approached a conventional level of significance (P = 0.089). There was no evidence of superiority for either of the pastes after normal home usage.

This study has suggested that the test product may have some advantage over the conventional paste at removing stain but the magnitude of difference would appear to be small and of little clinical relevance.