The effect of dentifrice quantity and toothbrushing behaviour on oral delivery and retention of fluoride in vivo.

While toothpaste F(-) concentration and rinsing regimen have well-characterised impacts on fluoride's effectiveness, other aspects of brushing regimen have much less well-established effects, in particular, dentifrice quantity and brushing duration. An in vivo study (n = 42) of oral fluoride delivery (i.e. oral disposition post-brushing), and retention (i.e. concentration of F(-) in saliva post-brushing, a known efficacy predictor), was performed to compare effects observed with those of dentifrice F(-) concentration and rinsing regimen. Subjects brushed with a NaF-silica dentifrice (Aquafresh Advanced, 1,150 ppm F(-) ) or a control dentifrice (250 ppm F(-) , same base), for 45, 60, 120 or 180 seconds with 0.5 or 1.5 g dentifrice, and rinsed with 15 ml water once or three times in a cross-over design. The F(-) concentration was measured in post-brushing expectorate, rinse and toothbrush washing samples, and in saliva between 5-120 minutes after brushing. Using 1.5 g versus 0.5 g dentifrice increased F(-) in all samples: oral retention of F(-) was almost doubled by this increase. Increasing duration of brushing had more complex effects. The amount of F(-) in the expectorate increased but decreased in both rinse and toothbrush washing samples. Oral F(-) retention increased, but only in the period 30-120 minutes after brushing. Over the ranges investigated, the order of importance on oral F(-) retention was: dentifrice F(-) concentration > quantity > rinsing regimen > brushing duration. Hence, increasing dentifrice quantity and, to a lesser extent, the duration of brushing, can elevate oral fluoride post-brushing. Evidence is accumulating that the importance of these variables to fluoride efficacy may have been underestimated.

A 6-month clinical study assessing the safety and efficacy of two cetylpyridinium chloride mouthrinses.

PURPOSE: To evaluate the effects of two experimental cetylpyridinium chloride (CPC) mouthrinses containing 0.075% and 0.10% CPC on the development of gingivitis and plaque versus a placebo control over a period of 6 months. METHODS: This was a randomized, single center, parallel group, double blind, positive and placebo controlled clinical trial. A 0.12% chlorhexidine rinse served as the positive control for validation of the methodology. At the beginning of the trial, 366 subjects were balanced and randomly assigned to treatment groups. Subjects received a dental prophylaxis and began rinsing twice a day with 15 ml of their assigned mouthwash for 30 seconds after brushing their teeth. Subjects were assessed for gingivitis and gingival bleeding by the Löe-Silness Gingival Index method and plaque by the Turesky modification of Quigley Hein Plaque Index at baseline and after 3 and 6 months of product use. Oral soft tissue health was also assessed. RESULTS: After 3 and 6 months, subjects rinsing with either 0.075% or 0.10% CPC had significantly (P< 0.0001) less gingivitis, gingival bleeding, and plaque, on average, than those on placebo. The 6-month mean reductions in gingivitis, gingival bleeding, and plaque for the 0.075% and 0.10% CPC rinses versus placebo were 23%, 30% and 17%, and 20%, 27% and 19%, respectively. There was no statistically significant difference in efficacy between the two CPC mouthrinses. Reductions at 3 months were similar to those seen at 6 months. Significant benefits were observed with chlorhexidine, thereby validating the study. CLINICAL SIGNIFICANCE: This study clearly demonstrates that CPC mouthrinses formulated to deliver therapeutic benefits when used twice daily can significantly prevent the development of gingivitis, gingival bleeding, and plaque over a 6-month period.

A clinical methods study of the effects of triclosan dentifrices on gingivitis over six months.

The basic design for human clinical trials which examine prevention of gingivitis recurrence is well known. However, the anti-gingivitis efficacy of triclosan-containing dentifrices has not been routinely demonstrated using this design, regardless of formulation. In an effort to better understand the subtleties of design which show triclosan efficacy, a study was undertaken to prospectively test how subjects with a range of baseline disease levels (which encompassed the range of gingivitis severity documented in the triclosan literature) benefit from a triclosan dentifrice. This trial was a randomized, double-blind, parallel group, six-month study where subjects brushed twice daily with either triclosan/pyrophosphate, triclosan/copolymer, triclosan placebo or sodium fluoride control (NaF) dentifrice following a prophylaxis. Both gingivitis and bleeding were measured using the Löe-Silness Gingival Index (GI) and plaque was measured using the Turesky Plaque Index. Comparisons between treatments were performed using an analysis of covariance. At month 3, the triclosan/pyrophosphate group had a relative mean plaque benefit of 14.4% versus the triclosan placebo group (with an associated p-value of 0.004), and subjects using triclosan/copolymer had a mean reduction in GI bleeding sites of 16.2% relative to those brushing with the NaF control (with an associated p-value of 0.031). The overall results did not demonstrate a treatment effect for gingivitis or plaque for either triclosan-containing dentifrice at month 6. There was evidence of modest anti-gingivitis efficacy in the triclosan placebo. In an effort to better understand how baseline disease severity may have impacted the trial outcome, additional analyses were performed to investigate whether the magnitude of a triclosan effect was related to baseline gingivitis levels. An analysis of covariance model incorporating a baseline group interaction effect indicated that the magnitude of the treatment differences depended on the baseline scores The effect was most pronounced for GI bleeding sites. Further analysis showed that differences between triclosan dentifrices and the NaF control dentifrice were only present for subjects with more than 33 to 63 bleeding sites, depending on the specific comparison. These findings were illustrated through a series of subset analyses on subjects with > or = 20 (entire study population), > or = 31, > or = 40 and > or = 45 baseline GI bleeding sites. The magnitude of the treatment effect for both GI and GI bleeding sites increased with each succeeding subset. Unlike that required for other antimicrobial agents used in oral care products, these findings suggest that a study design which includes subjects with more severe gingivitis at baseline has the required sensitivity to demonstrate treatment benefits for triclosan dentifrices.