The aim of the current study is to investigate the effect of different anticaries agents, such as experimental agents based on silver nanoparticles (SNPs) and silver diamine fluoride (SDF), on the micro-shear bond strength (μ-SBS) of composite resin applied to intact enamel (IE) or demineralized enamel (DE).

Sixty dental enamel fragments were collected from human third molars and categorized into 6 groups (n = 10): positive control (IE), negative control (DE), IE + SDF, DE + SDF, IE + SNP and DE + SNP. Samples from DE, DE + SDF and DE + SNP groups were subjected to pH cycling; superficial microhardness test was performed to confirm demineralization. Resin composite build-ups were applied to the samples (0.75-mm diameter and 1-mm height) after the treatments (except for IE and DE groups); μ-SBS was also evaluated. Samples were analyzed under a stereomicroscope at 40× magnification to identify failure patterns. Data were subjected to one-way analysis of variance, followed by Tukey's and Dunnett's tests (p < 0.05).

There was no significant difference among the IE, IE + SNP, DE + SDF, and DE + SNP groups. The IE + SDF and DE groups recorded the highest and the lowest μ-SBS values, respectively. Adhesive-type failures were the most frequent for all treatments.

Anticaries agents did not have a negative effect on the μ-SBS of composite resin when it was used on IE or DE.

This study was conducted to evaluate fluoride release and the micro-shear bond strength of resin-modified glass ionomer cement (RMGIC) in casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-remineralized caries-affected dentin (CAD).

Exposed dentin surfaces of 30 human third molar teeth were divided into 2 equal groups for evaluating fluoride release and the micro-shear bond strength of RMGIC to CAD. Each group was subdivided into 3 equal subgroups: 1) control (sound dentin); 2) artificially demineralized dentin (CAD); 3) CPP-ACP remineralized dentin (remineralized CAD). To measure fluoride release, 15 disc-shaped specimens of RMGIC (4 mm in diameter and 2 mm in thickness) were bonded on one flat surface of the dentin discs of each group. Fluoride release was tested using ion chromatography at different intervals; 24 hours, 3, 5, 7 days. RMGIC micro-cylinders were built on the flat dentin surface of the 15 discs, which were prepared according to the assigned group. Micro-shear bond strength was measured after 24 hours water storage. Data were analyzed using 1- and 2-way analysis of variance and the post hoc least significant difference test (α = 0.05).

Fluoride detected in solutions (at all intervals) and the micro-shear bond strength of RMGIC bonded to CPP-ACP-remineralized dentin were significantly higher than those bonded to artificial CAD (p < 0.05).

Demineralized CAD consumes more fluoride released from RMGIC into the solution for remineralization than CPP-ACP mineralized dentin does. CPP-ACP increases the micro-shear bond strength of RMGIC to CAD.

The purpose of this study was to assess the effect of single and combined applications of fluoride on the amount of fluoride release, and the remineralization and physical properties of enamel.

Each of four fluoride varnish and gel products (Fluor Protector, FP, Ivoclar Vivadent; Tooth Mousse Plus, TM, GC; 60 Second Gel, A, Germiphene; CavityShield, CS, 3M ESPE) and two fluoride solutions (2% sodium fluoride, N; 8% tin(ii) fluoride, S) were applied on bovine teeth using single and combined methods (10 per group), and then the amount of fluoride release was measured for 4 wk. The electron probe microanalysis and the Vickers microhardness measurements were conducted to assess the effect of fluoride application on the surface properties of bovine teeth.

The amount of fluoride release was higher in combined applications than in single application (p < 0.05). Microhardness values were higher after combined applications of N with FP, TM, and CS than single application of them, and these values were also higher after combined applications of S than single application of A (p < 0.05). Ca and P values were higher in combined applications of N with TM and CS than single application of them (p < 0.05). They were also increased after combined applications of the S with A than after single application (p < 0.05).

Combined applications of fluoride could be used as a basis to design more effective methods of fluoride application to provide enhanced remineralization.

The aim of this study was to evaluate the fluoride release of conventional glass ionomer cements (GICs) and resin-modified GICs.

The cements were grouped as follows: G1 (Vidrion R, SS White), G2 (Vitro Fil, DFL), G3 (Vitro Molar, DFL), G4 (Bioglass R, Biodinâmica), and G5 (Ketac Fil, 3M ESPE), as conventional GICs, and G6 (Vitremer, 3M ESPE), G7 (Vitro Fil LC, DFL), and G8 (Resiglass, Biodinâmica) as resin-modified GICs. Six specimens (8.60 mm in diameter; 1.65 mm in thickness) of each material were prepared using a stainless steel mold. The specimens were immersed in a demineralizing solution (pH 4.3) for 6 hr and a remineralizing solution (pH 7.0) for 18 hr a day. The fluoride ions were measured for 15 days. Analysis of variance (ANOVA) and Tukey's test with 5% significance were applied.

The highest amounts of fluoride release were found during the first 24 hr for all cements, decreasing abruptly on day 2, and reaching gradually decreasing levels on day 7. Based on these results, the decreasing scale of fluoride release was as follows: G2 > G3 > G8 = G4 = G7 > G6 = G1 > G5 (p < 0.05).

There were wide variations among the materials in terms of the cumulative amount of fluoride ion released, and the amount of fluoride release could not be attributed to the category of cement, that is, conventional GICs or resin-modified GICs.

Present study was undertaken to investigate the crystal growth onto synthetic hydroxyapatite (HA) seeds in pH 4.3 and pH 7.0 supersaturated solutions with different fluoride concentrations.

8 groups of pH 4.3 and 7.0 calcium phosphate supersaturated solutions were prepared with different fluoride concentrations (0, 1, 2 and 4 ppm). Calcium phosphate precipitates yield crystal growth onto the HA seed surface while solutions flow. For evaluation of crystallizing process, the changes of Ca²⁺, PO₄^3-, F^- concentrations of the inlet and outlet solutions were determined. The recovered solid samples were weighed to assess the amount of minerals precipitated, and finally determined their composition to deduce characteristics of crystals.

During the seeded crystal growth, there were significantly more consumption of Ca²⁺, PO₄^3-, F^- in pH 4.3 solutions than pH 7.0 (p < 0.05). As fluoride concentration increased in pH 4.3 solution, Ca²⁺, PO₄^3-, F^- consumption in experimental solutions, weight increment of HA seed, and fluoride ratio in crystallized samples were increased. There were significant differences among the groups (p < 0.05). But in pH 7.0 solution, these phenomena were not significant. In pH 7.0 solutions, analyses of crystallized samples showed higher Ca/P ratio in higher fluoride concentration. There were significant differences among the groups (p < 0.05). But in pH 4.3 solution, there were not significant differences in Ca/P ratio.

Crystal growth in pH 4.3 solutions was superior to that in pH 7.0 solutions. In pH 4.3 solutions, crystal growth increased with showed in higher fluoride concentration up to 4 ppm.

The usage of fluoride varnish for a moderate to low caries-risk group has not been well validated. This study aimed to evaluate the preventive and therapeutic efficacies of fluoride varnish on the initiated root caries.

Ten premolars were sectioned into quarters, further divided into two windows, one of which was painted with Fluor Protector (1,000 ppm fluoride, Ivoclar Vivadent). An initial lesion with a well-preserved surface layer was produced by pH cycling. Scanned line analysis using energy dispersive spectrometry determined the weight percentages of Ca and P in the demineralized layer. Scanning Electron microscopy and confocal laser scanning microscopy (CLSM) evaluated the varnish-applied root surfaces.

The mean lesion depth (SD) was 12.3 (2.6) µm (single cycling) and 19.6 (3.8) µm (double cycling). Double cycling extended the lesion depth, but induced no more mineral loss than single cycling (p < 0.05). The mean weight percentages of Ca and P between groups with and without varnish were not significantly different (p < 0.05). A CLSM showed varnish remained within 15 µm of the surface layer.

When a mild acid challenge initiated root tissue demineralization, the application of low-concentration fluoride varnish did not influence the lesion depth or the mineral composition of the subsurface lesion.