Effects of triclosan/copolymer dentifrice on dental plaque and gingivitis in a 3-month randomized controlled clinical trial: influence of baseline gingivitis on observed efficacy. (2002)

Triclosan is a broad-spectrum antimicrobial agent widely used in oral care products. In recent studies, a triclosan/pyrophosphate dentifrice has shown efficacy against dental plaque but not gingivitis. Further, experimental gingivitis studies on triclosan itself and in combination with other dentifrice ingredients demonstrate only moderate antimicrobial activity. In contrast, there are a number of other studies in the literature reporting the antigingivitis efficacy of triclosan/copolymer and triclosan/zinc citrate dentifrices. These dentifrices possess similar effects on dental plaque to triclosan/pyrophosphate, thus the lack of effect on gingivitis from triclosan/pyrophosphate was unexpected since comparable effects on dental plaque from similar formulations may infer similar antimicrobial activity and duration of action within the oral cavity. Therefore, the objective of this research was to understand the clinical variables important to observe the reported effects for triclosan dentifrice so this clinical model could in turn be used to test the effects of the triclosan/pyrophosphate dentifrice on gingivitis. To achieve this objective, it was determined that a suitable approach was to duplicate the methodology of previous successful clinical trials on triclosan/copolymer dentifrice in order to better understand the study design used to demonstrate the antigingivitis efficacy of triclosan-containing dentifrices. To this end, a prospective trial was conducted employing the same active product, clinical site, investigator and gingivitis/plaque examiner previously used. The study was a randomized, blinded, placebo-controlled, parallel group 3-month trial, which recruited subjects with Löe-Silness Gingival Index (GI) scores > or = 1.0 and Turesky Plaque Index (PI) scores of > or = 1.5. The study population consisted of 160 adults who brushed twice daily with either triclosan/copolymer or placebo control (containing copolymer) following a prophylaxis. Gingivitis and plaque were measured using the GI and PI, respectively, and scores were analyzed using a one-way analysis of covariance. There was no evidence that 3-month gingivitis or plaque scores (whole mouth or severity index) for the triclosan/copolymer group were different from the placebo group. Additional analyses were conducted on study population subgroups with increasing intervals of baseline GI bleeding sites to gauge the effect of baseline bleeding on the treatment effect. For subjects in the > or = 40 bleeding sites subset, triclosan/copolymer demonstrated a 4.2% GI and 15% gingivitis severity index reduction versus placebo at 3 months (0.10 < p < 0.20). These findings suggest that a study design which includes subjects with greater numbers of gingival bleeding sites at baseline may have the required sensitivity to demonstrate treatment benefits for triclosan/copolymer. However, additional experimental parameters remain to be fully articulated in order to replicate previously successful trials. The overall results of this trial are consistent with the experimental gingivitis results, and indicate that, even when formulated with the copolymer, triclosan as an oral antimicrobial agent possesses limited activity as an antigingivitis ingredient.