A model for studying the effects of mouthrinses on de novo plaque formation
Authors: Ramberg Per , Furuich Yasushi , Lindtie Jan , Gaffar Abdul 
Published: December 2005

Abstract The aim of the present study was to describe a 4‐day no oral hygiene model to assess the pattern of de novo plaque formation and to use this model to appraise the potential of some mouthwash preparations to retard or inhibit plaque formation in the human dentition. 10 subjects were recruited for the trial. During a preparatory period, the participants were exposed to repeated professional plaque control and given oral hygiene instruction to eliminate signs of gingivitis. At the end of the preparatory period, each participant received a final professional tooth cleaning and was subsequently told to abstain from mechanical plaque control efforts for the next 4 days. They were asked to rinse twice daily for 60 s with 10 ml varying test solutions. On Day 4, the volunteers were exposed to a new clinical examination and the presence and amount of plaque were examined by the use of the plaque index system (Pll). The participants were subsequently given a professional tooth cleaning and asked to exercise proper self performed plaque control during the next 10 days. A new test period was then initiated. 6 different mouthwash preparations were tested in each subject namely. (1) placebo (a negative control rinse), (2) Veadent* mouthrinse. (3) Listerine* mouthrinse. (4) 0.06% triclosan + polyvinyl phosphonic acid (PVPA). (5) 0.06% triclosan + phenolic flavor and (6) O.J2% chlorhexidine digluconate (a positive control rinse). The results from the study revealed that the mean Pll values for individuals, groups of teeth and tooth surfaces provide an adequate but gross overall estimation of the potential of a given mouthrinse to retard/inhibit plaque build up. More detailed information on the effects of the test rinses could be obtained by data describing the % distribution of different Pll score categories; a high frequency of score 0 describes the potential of a mouthrinse to maintain tooth surfaces free from plaque while a low frequency of score 2/3 describes the ability of a treatment to retard/prevent gross plaque formation. The plaque pattern displays finally allowed assessment of the magnitude of plaque prevention, in comparison to the positive and negative controls, that could be achieved by a given compound in various parts and surfaces of the dentition. In this model, all test rinses (i) were significantly more effective than the placebo rinse in retarding de novo plaque build up and (ii) had a minor effects on plaque build up in the maxillary molars and at the approximal surfaces. The chlorhexidine rinse was more effective than the other mouthwash preparations tested (except the mouth‐rinse containing triclosan and phenolic flavor) in all parts of the dentition. Both the Veadent? and the Listerine5 mouthrinses were significantly less effective than the chlorhexidine rinse. The triclosan + PVPA containing mouthrinse was less effective than the chlorhexidine rinse in the molars and at the buccal tooth surfaces. The triclosan +“phenolic flavor” containing mouthrinse had the same magnitude of efficacy as the chlorhexidine rinse in all parts of the dentition.