Efficacy of a 0.15% benzydamine hydrochloride and 0.05% cetylpyridinium chloride mouth rinse on 4-day de novo plaque formation.

OBJECTIVE To evaluate the effect of a mouth-rinse formulation combining benzydamine hydrochloride and cetylpyridinium chloride (BNZ+CPC) in preventing de novo plaque formation, in comparison with CPC and placebo mouth rinses. PATIENTS AND METHODS This was a controlled, observer-blind, cross-over study. In this model of plaque re-growth, subjects received a session of oral prophylaxis and were directed to withdraw oral hygiene measures for the next 4 days, using only the mouth rinse assigned. The outcome parameters were the plaque index (PlI) and gingival index (GI). In addition, microbiological evaluation of the subgingival microflora, by means of culture, was performed, as well as patient-based variables. Data analysis was carried out using anova for Latin-square design. RESULTS The analysis of variance showed a significant statistical difference between the BNZ+CPC association and placebo (p<0.0001). No differences between CPC and placebo were detected considering multiple comparisons between treatments. The 90% confidence interval of the differences between BNZ+CPC and CPC showed no equivalence between treatments, being the PlI lower in the BNZ+CPC group. No significant difference between groups in GI was observed. Mean anaerobic colony-forming units (CFU) demonstrated a significant increase between visits in all groups (p<0.001) and differences among groups were not significant. Subjects treated with BNZ+CPC frequently reported "tingling mouth" and "numbness mouth". CONCLUSION Within the limitations of the study model, the BNZ+CPC combination showed a statistically significant plaque-inhibitory capacity, as compared with the placebo mouth rinse, and an additive effect as compared with CPC. No relevant clinical or microbiological adverse effects were detected.