Influence of a SLS-containing dentifrice on the anti-plaque efficacy of a chlorhexidine mouthrinse

Background: Chlorhexidine (CHX) and sodium lauryl sulphate (SLS), the most widely used detergent in dentifrice, may counteract. Consequently, studies about this interaction suggested that care is required when combining both these compounds, even when they are introduced separately into the oral cavity. The purpose of the present study was to investigate the effect of toothbrushing with a SLS-containing dentifrice in one jaw, on the plaque inhibition of a CHX mouthrinse in the opposite jaw during a 4-day study period. Methods: The study was an examiner-blind, randomised two-cell, crossover design. It used a 4-day plaque accumulation model to compare two different oral hygiene regimens with a washout period of 17 days. Sixteen healthy volunteers were enrolled in the study and received a thorough dental prophylaxis at the beginning of each 4-day test period. One jaw (upper or lower) was randomly assigned as the “study” jaw. The opposite jaw was assigned as the “dentifrice” jaw and served only to introduce the effect of brushing with a dentifrice in the study model. Two oral hygiene regimens were evaluated. During one randomly assigned test period, the “dentifrice” jaw was treated by toothbrushing with a 1.5% SLS-containing dentifrice and rinsed together with the “study” jaw with 0.2% CHX, thus forming regimen 1. As a control during the other test period, both the “dentifrice” jaw and “study” jaw were only rinsed with 0.2% CHX, forming regimen 2. No other oral hygiene methods were allowed. After 4 days of undisturbed plaque accumulation, the amount of plaque was evaluated ( Silness & Löe 1964 ). The “study” jaw was used to study the effect of the two regimens on the level of plaque accumulation at the end of the 4-day period. Results: The overall plaque index was 0.36 for regimen 1 and 0.34 for regimen 2. There was no significant difference in plaque accumulation between the two regimens. Conclusions: Within the limitations of the present study design, it can be concluded that ordinary brushing with a 1.5% SLS-containing dentifrice (Colgate Bi-Fluor), followed by rinsing with water does not appear to reduce the level of plaque inhibition offered by a post-brushing CHX rinse.