Total Protein and Viable Counts to Evaluate Interproximal Biofilm Removal

Objective: To evaluate viable bacterial count and protein concentration in assessing the efficacy of interproximal plaque removal between two power toothbrushes, the Sonicare® FlexCare toothbrush and the Oral-B® Professional Care 9000 Triumph® toothbrush. Methods: An in vitro tooth model was used to evaluate the brushing efficacy of both active toothbrushes in removing dental plaque biofilm from the interproximal spaces of mandibular molar teeth, which are beyond the reach of toothbrush bristles. Microcosmic oral biofilms from pooled saliva were grown in a constant depth film fermenter (CDFF) for 8 days on hydroxyapatite (HA) disks. Disks were then inserted between a pair of molar teeth in the tooth model at a distance of 2-4 mm from the bristle tips. Teeth brushing was performed for 15 seconds; no direct contact was made between the bristles and the plaque biofilms. Plaque removal efficacy was determined directly by enumeration of the percentage of viable bacteria removed from the HA disks due to brushing. An indirect assessment followed from calculating the total protein yield from the same sample of removed biofilm using the CBQCA assay. Results: For viable counts, the active Sonicare® FlexCare removed a significantly greater percentage of biofilm bacteria when compared to the inactive state (p<0.0001) and a threefold higher plaque removal efficacy when compared to the active Oral-B® Triumph® (p=0.0001). For protein counts, the active Sonicare® FlexCare removed a significantly higher percentage of biofilm bacteria when compared to the inactive state (p<0.0001) and a 1.5 fold higher removal efficacy when compared to the active Oral-B® Triumph® (p=0.0016). Conclusion: A statistically significant correlation was found between the percentage of protein and viable cell count reductions for both variables, indicating protein content as a valid indirect measure alternative for assessing efficacy of biofilm removal in this model compared to direct measures using viable cell counts.