Method: After institutional review and informed consent, healthy adults were enrolled in a study to assess the between-visit consistency of plaque measurement for overnight and post-brush plaque. At Day 1, subjects with overnight (unbrushed) plaque swished with a fluorescein rinse and expectorated, cheek retractors were inserted, and a single digital image was collected under standardized lighting conditions. After routine hygiene with a regular anticavity dentifrice (Crest® Cavity Protection) and standard manual toothbrush, disclosing and imaging were repeated. Approximately 1-week later, the imaging-brushing-imaging sequence was repeated. Each digital image was analyzed blind to visit sequence to determine area (%) plaque coverage, and paired images were compared to assess between-visit correlation.
Result: A total of 51 subjects had prebrush and postbrush plaque measurements at both visits, and all data were included in the analysis. Mean (SD) age was 37.4 (15.4) ranging from 18-71 years, and females comprised a majority (58%) of study subjects. Plaque coverage varied across visits, ranging from 2.2-79.2% before brushing and 2.5-42.0% after brushing. By visit, mean prebrush plaque levels were 18.8 & 19.8 at Visit 1 & 2 (p=0.42), versus postbrush area of 6.8 & 7.2 (p=0.38). Both the prebrush (r=0.84) and postbrush (r=0.80) plaque areas were well-correlated.
Conclusion: Use of image analysis demonstrates a high level of between-subject variability in natural plaque accumulation and removal, that is highly reproducible between-visits.