Background and Aim: Although toothbrushing is still the most effective method in plaque reduction, it is insufficient for total plaque removal. Considering this limitation, it is suggested that toothbrushing could be aided by chemical methods. For this purpose, it is advised to use some kind of mouthrinses before toothbrushing to increase the rate of microbial plaque removal. Several prebrushing mouthrinses are available in the market and comparing their efficiency is valuable for dentists. The aim of this study was to investigate and compare the effect of two prebrushing mouthrinses, Plax and Irsha, on dental plaque reduction.

Materials and Methods: This clinical trial was carried out as an interventional and triple blind protocol, using completely random block design. For this purpose, questionnaire and initial examination chart was filled for 50 healthy volunteers between the age of 18 and 40 years and finally 30 individuals were selected based on the inclusion/exclusion criteria. If scaling and polishing was necessary, it was performed at least 2 weeks before starting the main program. Then, each volunteer participated in a 4 steps program, including one step toothbrushing without use of mouthrinse and three steps toothbrushing after use of one of the mouthrinses (Plax, Irsha, Placebo). Data were analyzed by SPSS software using factorial analysis, ANOVA and Tukey’s multiple comparison tests with p<0.05 as the limit of significance.

Results: Toothbrushing without use of mouthrinse decreased the amount of plaque, significantly (P<0.0001). Use of mouthrinse without toothbrushing decreased the amount of plaque significantly (P<0.0001). The amount of plaque reduction after use of various mouthrinses (Plax, Irsha, Placebo) showed no statistical differences (P=0.761). Use of the mouthrinses before toothbrushing, had no statistically significant effect on the final results after toothbrushing (P=0.331).

Conclusion: According to the findings of the present study, although using mouthrinses decrease the amount of dental plaque significantly, but the prebrushing mouthrinse didn't show statistically significant effect on final result after toothbrushing.