Comparison of a stabilized stannous fluoride/sodium hexametaphosphate dentifrice and a zinc citrate dentifrice on plaque formation measured by digital plaque imaging (DPIA) with white light illumination

OBJECTIVES: The objectives of this study were to verify use of a white light-illuminated adaptation of an established digital plaque image analysis (DPIA) technique to measure changes in plaque levels, and to compare the antiplaque efficacy of a 0.454% stannous fluoride/sodium hexametaphosphate dentifrice (SnF2/SHMP) and a 0.76% sodium monofluorophosphate/zinc citrate (ZnCit/SMFP) dentifrice using the white light DPIA system. METHODS: White Light DPIA Qualification--17 subjects were enrolled in the study. The following four images were captured on different days: a) non-disclosed morning plaque; b) disclosed morning plaque; c)just-brushed plaque; and d) post-prophylaxis plaque levels. Comparative Dentifrice Assessment-Following the qualification study, 21 subjects were enrolled in the dentifrice assessment. During Phase I (two weeks acclimatization phase), subjects used a standardized oral hygiene regimen twice per day, consisting of a sodium fluoride dentifrice and a standard flat-profile manual toothbrush. In Phase II (two-week treatment phase), subjects were randomized to one of two treatment groups: SnF2/SHMP dentifrice (Crest Pro-Health) or the ZnCit/SMFP formulation (Viadent). During each phase, plaque levels were assessed in the morning prior to the morning tooth brushing (a.m.), post-brushing in the morning (p.b.), and in the afternoon (p.m.). RESULTS: White Light DPIA Qualification--All 17 subjects completed the trial. The white light modification of DPIA successfully distinguished known variations in plaque coverage. Mean plaque coverage of the 12 anterior facial surfaces, as determined by the system for the four images, was: a) 0.07%; b) 11.44%; c) 4.99%; and d) 2.16%. Comparative Dentifrice Assessment-All 21 subjects completed the study. The SnF2/SHMP dentifrice provided a statistically significant 25% lower a.m. pre-brushing plaque level (p = 0.0385) versus ZnCit/SMFP. SnF2/SHMP also showed a directional 23% lower p.m. plaque (p = 0.09) level, and 15% less (p = 0.10) post-brushing plaque compared to ZnCit/SMFP. CONCLUSION: The white light DPIA system was shown to be a sensitive method to measure changes in plaque levels. Using this system, a SnF2/SHMP dentifrice was found to be significantly more effective than a ZnCit/SMFP dentifrice in the prevention of overnight plaque growth.