Protection of dentin by triclosan toothpaste in a bacterial demineralisation model

The effect of the addition 0.3% triclosan to a non-fluoride and fluoride toothpaste was tested in an in vitro demineralisation model. This model comprised bovine dentin specimens overlaid with acidogenic Streptococcus mutans suspensions in agarose at two different concentrations of cells. Before the experiments, subsurface lesions were made in the dentin specimens in a methylcellulose gel system. In a first set of experiments, the toothpastes were diluted in the S. mutans suspensions at w/v dilutions of 1:100, 1:1,000, and 1:10,000, respectively. After 22 h of incubation at 37 degrees C, the suspensions were removed and assessed for calcium, lactate and pH. In this set of experiments, an additive protective effect of triclosan to the non-fluoride toothpaste was found at the lowest concentration of S. mutans cells and when the toothpaste was relatively undiluted (1:100 w/v). No additive effect was observed to the fluoride toothpaste. In the second set of experiments, the specimens were immersed daily for 3 min in 30% (w/v) slurries of the toothpastes before the 22-h incubations with the S. mutans suspensions. At the lowest concentration of S. mutans cells, triclosan had an additional protective effect to the non-fluoride and fluoride toothpaste. It is concluded that triclosan may contribute to the protection of dentin under a mild acid attack both when it is present in dental plaque and when it has been adsorbed to the dentin.