49 - Can S-PRG Fillers in Different Vehicles Act on Dentin Permeability?

Abstract

The exposure of dentin to the oral environment often leads to the development of dentin hypersensitivity (DH) partially due to the permeability of this mineralized tissue. Among the strategies to relief its symptoms, ions that minimize demineralization and reinforce mineralized tissues are often employed. Recently, one light-curing varnish containing surface pre-reacted glass (S-PRG) fillers (PRG Barrier Coat) was developed with this purpose. Furthermore, it presents aluminum, which is attributed to the clinical relief of DH. However, due to the presence of these fillers in a light-curing resinous matrix, the effect of the matrix cannot be disregarded. Therefore, the aim of this study was to investigate the effect of a S-PRG-based varnish, a toothpaste containing 30 wt.% of S-PRG fillers, a resin infiltrant (Icon) and a NaF-based varnish (Duraphat) on the dentin permeability in vitro. The permeability of the dentin disks (1.0 0.2 mm) was evaluated using Flodec. The specimens were distributed in 4 groups (n=8) and the minimum (pMin, with smear layer) and maximum (pMax, without smear layer) were recorded. Thereafter, each specimen was treated with one of the designated product and the permeability after treatment (pTreat) was recorded. Then, specimens were subjected to a 1-min erosive challenge and the final permeability (pEro) was recorded. The data was transformed in Log10 and analyzed using 2-way repeated measures ANOVA (alpha=0.05). The results evidenced no difference between groups for the pMin and pMax values, assuring a standardized baseline for all tested conditions. There was no difference in pTreat when comparing the two S-PRG-based vehicles. For pTreat and pEro, the lowest permeability was seen for the group treated with the resin infiltrant, reaching values closest to pMin. Likely, its homogeneous TEGDMA layer constituted a mechanical barrier. NaF varnish also effectively reduced dentin permeability after treatment. Therefore, it can be concluded that S-PRG-based products vehicle did not reduce the dentin permeability in vitro, so its effective action for DH might be attributed to other mechanisms rather than by an obliterating process.