Caries-preventive effect of anti-erosive and nano-hydroxyapatite-containing toothpastes in vitro
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The aim of the study was to investigate the caries-preventive effect of newly developed fluoride and fluoride-free toothpastes specially designed for erosion prevention. The hypothesis was that these products might also show superior caries-inhibiting effect than regular fluoride toothpastes, since they were designed for stronger erosive acid challenges.
Materials and methods
Enamel specimens were obtained from bovine teeth and pre-demineralized (pH = 4.95/21 days) to create artificial caries lesions. Baseline mineral loss (ΔZB) and lesion depth (LDB) were determined using transversal microradiography (TMR). Ninety specimens with a median ΔZB (SD) of 6027 ± 1546 vol% × μm were selected and randomly allocated to five groups (n = 18). Treatments during pH-cycling (14 days, 4 × 60 min demineralization/day) were brushing 2×/day with AmF (1400 ppm F−, anti-caries [AC]); AmF/NaF/SnCl2/Chitosan (700 ppm F−/700 ppm F−/3500 ppm Sn2+, anti-erosion [AE1]); NaF/KNO3 (1400 ppm F−, anti-erosion [AE2]); nano-hydroxyapatite-containing (0 ppm F−, [nHA]); and fluoride-free toothpastes (0 ppm F−, negative control [NC]). Toothpaste slurries were prepared with mineral salt solution (1:3 wt/wt). After pH-cycling specimens presenting lesion, surface loss (mainly by NC and nHA) were discarded. For the remaining 77 specimens, new TMR analyses (ΔZE/LDE) were performed. Changes in mineral loss (ΔΔZ = ΔZB − ΔZE) and lesion depth (ΔLD = LDB − LDE) were calculated.
All toothpastes caused significantly less demineralization (lower ΔΔZ) than NC (p < 0.05, ANOVA) except for nHA. The fluoride toothpastes did not differ significantly regarding ΔΔZ and ΔLD (p > 0.05, ANOVA).
While both anti-erosive and anti-caries toothpastes reduced mineral loss to a similar extent, the fluoride-free nano-hydroxyapatite-containing toothpaste seemed not to be suitable for inhibition of caries demineralization in vitro.
KeywordsEnamel Erosion Toothpaste Fluoride Stannous Nano-hydroxyapatite
Compliance with ethical standards
Conflict of interest
The authors declare they have no conflict of interest.
The study was funded by both institutions involved and Mrs. Santos was granted a scholarship from the Science Without Borders (CSF) program from CNPq, Brazil (process number 238553/2012-4).
This article does not contain any studies with human participants or animals performed by any authors.
For this type of study, formal consent is not required.
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