The effect of the addition 0.3% triclosan to a non-fluoride and fluoride to
othpaste was tested in an in vitro demineralisation model. This model compr
ised 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 met
hylcellulose gel system. In a first set of experiments, the toothpastes wer
e 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 s
uspensions were removed and assessed for calcium, lactate and pH. In this s
et of experiments, an additive protective effect of triclosan to the non-fl
uoride toothpaste was found at the lowest concentration of S. mutans cells
and when the toothpaste was relatively undiluted (1:100 w/v). No additive e
ffect was observed to the fluoride toothpaste. In the second set of experim
ents, 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 additiona
l protective effect to the non-fluoride and fluoride toothpaste. It is conc
luded that triclosan may contribute to the protection of dentin under a mil
d acid attack both when it is present in dental plaque and when it has been
adsorbed to the dentin.