An in vitro comparison of dentifrice formulations in three distinct oral microbiotas

In vitro biofilm models, representative of some aspects of nascent, supra-gingival plaques (Hydroxyapatite Disc Biofilm Models), developed supra-gingival plaques (Modified Drip-flow Biofilm Reactors) and sub-gingival plaques (Multiple Sorbarod Devices) were used to compare the antimicrobial effects of a triclosan-containing dentifrice with a stannous fluoride and zinc lactate combination.

Triplicate salivary biofilm microcosms were maintained for 2d (hydroxyapatite discs), 5d (Sorbarods) or up to 6d (drip flow reactors). Dentifrice slurries (10%, w/v) were added once to the discs and repeatedly to the Drip Flow Reactors and Sorbarods. Plaques were analysed by differential culture and gravimetrically.

Whilst both dentifrices were comparably effective at reducing viability and plaque accumulation in mature supragingival plaques, the triclosan dentifrice produced comparatively larger reductions in total streptococci and anaerobes in nascent plaques (p<0.05) and greater reductions in Gram-negative anaerobes and streptococci in subgingival plaques.

We have used a multi-model approach to determine the effectiveness and specificity of dentifrices against compositionally distinct plaques. Whilst both formations reduced bacterial viability and plaque accumulation, their effects could be differentiated in nascent and deep plaques where the triclosan dentifrice caused larger viability reductions.