Objectives: A 10-week, double-blind, placebo-controlled clinical study on 140 male subjects was conducted to determine the effect on plaque and gingivitis of 5 dentifrices containing various thiocyanate (SCN-)/hydrogen peroxide (H2O2) combinations.
Materials and methods: The dentifrices consisted of a gel base without any detergents or abrasives (placebo, group A) to which SCN- and/or H2O2 were added as follows: 0.1% SCN- (group B), 0.5% SCN- (group C), 0.1% SCN-/0.1% H2O2 (group D), 0.5% SCN-/0.1% H2O2 (group E) and 0.1% H2O2 (group F). A baseline examination was performed in which the Silness and Löe Plaque Index (PI), the Mühlemann and Son Sulcus Bleeding Index (SBI), and the amount of gingival crevicular fluid (GCF) were recorded using the Periotron 6,000 on teeth 16, 12, 24, 36, 32, and 44. The subjects were randomly assigned to either the placebo group (n = 40) or one of the test groups (n = 20) and used their respective dentifrices over a period of 8 weeks. Finally, each group used the placebo for another 2 weeks (wash-out). Re-examinations were performed after 1, 4, and 8 weeks and the 2-week wash-out period employing the clinical parameters used at baseline. Intragroup changes were analyzed with the Wilcoxon signed-ranks test, using the baseline and wash-out points as references. The Mann-Whitney U test was used for comparisons between the treatment groups and the placebo group.
Results: At the 8-week examination, the plaque index in group E (p = 0.017) and group F (p = 0.032) was lower than in the placebo group. The Sulcus Bleeding Index in group F after 1 week was increased (p = 0.023) and the SBI in group E after 8 weeks was reduced (p = 0.047) as compared to the placebo group.
Conclusion: The results demonstrated that a dentifrice containing 0.5% SCN- and 0.1% H2O2 but no detergents or abrasives inhibited plaque and decreased gingivitis.