Fluoride varnishes with calcium glycerophosphate: fluoride release and effect on in vitro enamel demineralization

Abstract

The aims of this study were (1) to assess the amount of fluoride (F) released from varnishes containing calcium glycerophosphate (CaGP) and (2) to assess the effect of the experimental varnishes on in vitro demineralization. Six test groups using 5 varnishes: base varnish (no active ingredients); Duraphat® (2.26% NaF); Duofluorid® (5.63% NaF/CaF2); experimental varnish 1 (1% CaGP/5.63% NaF/CaF2); experimental varnish 2 (5% CaGP/5.63% NaF/CaF2); and no varnish were set up. In stage 1, 60 acrylic blocks were randomly distributed into 6 groups (n = 10). Then 300 µg of each varnish was applied to each block. The blocks were immersed in deionized water, which was changed after 1, 8, 12, 24, 48 and 72 hours. Fluoride concentration in the water was analyzed using a fluoride electrode. In stage 2, 60 bovine enamel samples were distributed into 6 groups (n = 10), and treated with 300 µg of the respective varnish. After 6 h the varnish was removed and the samples were subjected to a 7-day in vitro pH cycle (6 h demineralization/18 h remineralization per day). The demineralization was measured using surface hardness. The results showed that both experimental varnishes released more fluoride than Duofluorid® and Duraphat® (p < 0.05), but Duraphat® showed the best preventive effect by decreasing enamel hardness loss (p < 0.05). Therefore, we conclude that even though (1) the experimental varnishes containing CaGP released greater amounts of F, (2) they did not increase in the preventive effect against enamel demineralization.

Remineralizing effect of commercial fluoride varnishes on artificial enamel lesions

“…Furthermore, it is suggested that, although all varnishes remained on the enamel surface for the same amount of time, the fluoride released by ENA might have been higher than that released by the other varnishes, although this property was not evaluated in the present study. Carvalho et al 23 observed that the greater contact time promoted by ENA varnish may have influenced the amount of fluoride deposited on the enamel, thus suggesting that the lower viscosity of certain varnishes may promote stronger retention on enamel, provide greater contact with the storage medium, and allow greater release of fluoride. In addition, Al Dehailan et al 21 observed that different varnish compositions may interfere with the remineralization of enamel lesions, the release of fluoride and the deposition of fluoride on the dental surface.…”

“…19,20 Some studies investigated whether these varnishes: 1) release enough fluoride in the surrounding storage media to allow the formation of CaF 2 reservoirs on the enamel substrate and/or, 2) present a remineralization effect on artificial enamel lesions. 11,21,22,23,24,25 Only Fernández et al 11 evaluated the fraction of fluoride soluble in varnish needed for immediate reaction with hard dental tissues to form CaF 2 -like products, and the insoluble fluoride particles present in the varnish matrix, which could prolong the reaction when dissolved by saliva.…”

Comparison of resin-based and glass ionomer sealants with regard to fluoride-release and anti-demineralization efficacy on adjacent unsealed enamel

“…Although several studies have measured the amount of fluoride released by different dental materials [12][13][14] , the variations in the results can be attributed to differences in the methodologies used, specimen sizes, frequency of renewal, and quality of storage media used to measure fluoride level 26) . In the present study, bovine teeth were employed instead of human teeth.…”

“…They reported that materials releasing larger quantities of fluorides exhibited greater inhibition of demineralization 8,11,13) . However, Carvalho et al reported that increasing quantities of fluoride released by varnishes did not demonstrate any preventive effects on tooth demineralization 14) . Therefore, the effectiveness of fluoridated materials against caries and what data that have been obtained are somewhat contradictory.…”

Remineralization ability of fluoride varnish containing tricalcium phosphate by time

“…Most research about an in-vitro test of fluoride varnish has investigated the amount of fluoride release 18,19) . Evidently, the amount of fluoride release means remineralization because the amount of fluoride release is directly proportional to the amount of remineralization 20) .…”