The Relative Efficacy of Fluoride Toothpastes Assessed with pH Cycling

Abstract

This study addressed the dose response between fluoride toothpastes and in vitro de- and remineralization, to predict the efficacy of toothpastes and understand the mode of action in the range 0–3,000 ppm F. Enamel lesions were pH-cycled with calcium uptake and loss being assessed daily. Both ‘shallow’ (about 50 µm deep) and ‘deep’ (about 200 µm deep) lesions were studied. F treatments were given in 30 (w/v)% toothpaste dilutions for up to 5 min daily. Calcium loss during the demineralization periods showed a dose response, resulting in 72% reduction for 3,000 ppm F compared to 0 ppm F. Calcium uptake during remineralization was increased in the F compared to non-F groups, with F concentration being less important than its mere presence. Significant differences were observed in F response between shallow and deep lesions, suggesting that this parameter should be included when testing caries-preventive products. Microradiographic analysis showed that lesion depth and severity had increased significantly in the non-F groups. In the F groups, the original lesion was partly remineralized, while a new lesion had formed beyond the original lesion front. Mineral loss of this second lesion correlated inversely with the F concentration of the treatments. These data revealed that fluoride can drive demineralization further into enamel by making the surface tissue less soluble, hence by not neutralizing acids penetrating into the tissue. It is also concluded that depth analysis of mineral uptake and loss is important to understand the mode of action of different F products.

The effect of ozone on progression or regression of artificial caries-like enamel lesions in vitro

“…The results of the current study are in accordance with ten Cate et al 22 who found that when shallow ('early') lesions were studied the predominant effect of fluoride was to inhibit demineralisation up to 50% in the 'classical' fluoride range 0-1,500 ppm, and this increased to 70% when 3,000 ppm F -pastes were given. The results of the current study indicated that ozone alone has a minimal effect but this was enhanced when fluoride containing products were used in combination with use of ozone and this is in agreement with recently published study that also disputed the efficacy of ozone without its constituent adjunct therapies.…”

Caries-preventive effect of anti-erosive and nano-hydroxyapatite-containing toothpastes in vitro

“…Besides, as in the natural caries process, in the present model demineralizing challenges were followed by remineralizing phases, allowing the fluoride ion to have an effect on both phases. Both the number of demineralization phases (6× demin/day) as well as the total demineralization time per day (4 h/day) was similar to other pHcycling studies [38,39]. These conditions resulted in subsurface initial caries lesions showing net demineralization in our pilot tests (data not shown), so this model fulfilled the conditions intended to be simulated.…”

Effects of a chewing gum containing phosphoryl oligosaccharides of calcium (POs-Ca) and fluoride on remineralization and crystallization of enamel subsurface lesions in situ

“…The use of bovine enamel has been verified in a number of in vitro studies to evaluate the effect of anticariogenic agents on enhancing enamel remineralization and inhibiting enamel demineralization. 22 Using the in situ model, human and bovine enamel have shown similar characteristics in subsurface lesion remineralization under irradiation or abrasion influence. 23 However, bovine enamel is not similar to human enamel in some aspects; for example, it may have a higher porosity, 24 potentially leading to a faster demineralization rate.…”