A SHORT-TERM CLINICAL-STUDY DESIGN TO INVESTIGATE THE CHEMICAL PLAQUEINHIBITORY PROPERTIES OF MOUTHRINSES WHEN USED AS ADJUNCTS TO TOOTHPASTES - APPLIED TO CHLORHEXIDINE

The removal of plaque by toothbrushing with toothpaste is the most com mon form of plaque control in the developed world. However, the use of chemical adjuncts such as mouthrinses is increasing. In practice mout hrinses and toothpaste are used together, however, in many clinical tr ials, employed to assess mouthrinse activity, toothpaste use is suspen ded. This fails to measure the effect of chemical interactions which a re known to occur between toothpaste ingredients and mouthrinses. The objective of this trial was to develop a methodology which would asses s the adjunctive chemical plaque inhibitory action of mouthrinses, whe n used with toothpaste but without the indeterminate variable of tooth brushing. The study was a single blind, randomised, 7-way crossover de sign, based on a variation of a 4 day plaque regrowth model. The 2xdai ly rinsing regimens produced increasing plaque scores in the following order: (1) water/chlorhexidine, (2) chlorhexidine/water, (3) chlorhex idine/toothpaste slurry, (4) toothpaste slurry/chlorhexidine, (5) wate r/toothpaste slurry, (6) toothpaste slurry/water, (7) water/water. Chl orhexidine and water or chlorhexidine and toothpaste slurry combinatio ns produced significantly lower plaque scores than water alone. Slurry and water combinations resulted in less plaque than water alone, but differences were not significant. Toothpaste slurry and chlorhexidine produced significantly increased plaque scores compared to chlorhexidi ne and water. The study suggests that, outside the Hawthorne effect, c hlorhexidine rinses would be less effective in reducing plaque when us ed with toothpaste than when used alone. The methodology could be empl oyed as a screening tool for the evaluation of mouthrinses expected to be used as adjuncts to normal oral hygiene methods. The same could be used to optimise oral hygiene regimens which include the use of mouth rinses.