Antifungal Efficacy of a Permanent Silicon Soft Liner Containing Silver Nanoparticles.

Objectives: This study aimed to evaluate the in vitro antifungal efficacy of addition of silver nanoparticles (SNPs) to Mucopren® silicone soft liner material. Materials and Methods: Twenty disc samples (8 × 2 mm) of Mucopren® silicone soft liner containing 0wt% (control), 0.5wt%, 1wt%, 2wt%, and 3wt% SNPs were fabricated. Samples were powdered and added to 150 mL of Sabouraud dextrose agar culture medium and placed on separate culture dish plates. Each plate was inoculated with 106 colony forming units per milliliter (CFUs/mL) of Candida albicans (PTCC 5027) according to the CLSI protocol, and incubated at 37℃. The colony count was verified at 24 h, and the antifungal effect of the samples was evaluated according to the percentage of viable cells in the 2 subgroups with/without thermocycling. Data were analyzed using SPSS version 20 via ANOVA and t-test (P<0.05). Results: All experimental groups showed higher antifungal activity than the control group, and this effect was dose-dependent (P<0.05). The lowest colony count was recorded in the 3wt% group. Thermocycling had no significant effect on the antifungal efficacy, except in 0.5wt% concentration of SNPs (P=0.013). Conclusion: Addition of SNPs to Mucopren soft liner conferred antifungal effects. Further mechanical stability and toxicity studies are still required.

Effect of Incorporation of Silver Nanoparticles on the Tensile Bond Strength of a Long term Soft Denture Liner.

OBJECTIVES: This study aimed at assessing the effect of the addition of silver nanoparticles (SNPs) to a silicone soft liner on its tensile bond strength to denture base resin. MATERIALS AND METHODS: SNPs were added to Mucopren cold cure soft liner in 0 (control), 0.5, 1, 2, and 3 wt% concentrations and bonded in 120 stainless steel molds with processed heat cure acrylic resin blocks. Liner/resin combination samples were divided into two groups. The first half was stored for 2 days in distilled water at 37°C and then subjected to tensile bond strength, while the other half were thermocycled 3000 times before testing. Mean bond strength, expressed in mega pascals (MPa), was determined in the tensile test with the use of a universal testing machine at a crosshead speed of 5 mm/min. STATISTICAL ANALYSIS: Data were analyzed using SPSS via one-way analysis of variance test, t-test, and Tukey's posthoc, at a 95% confidence level (p < 0.05). RESULTS: Addition of SNPs and thermocycling both caused a significant reduction in the tensile bond strength of Mucopren to acrylic resin; however, in the thermocycled group, the bond strength increased with the increase in the concentration of SNPs (p < 0.001). CONCLUSION: Addition of SNPs to Mucopren soft silicone liner reduces its tensile bond strength to denture acrylic resin.

Remineralization of artificial caries in primary teeth by grape seed extract: an in vitro study.

Background and aims. Promoting remineralization is the ultimate goal of clinical prevention of caries lesion. The present in vitro study aimed to investigate the effect of grape seed extract (GSE) on artificial enamel caries in primary human teeth. Materials and methods. Seventeen human sound primary incisors were sectioned mesiodistally. The tooth slices were placed in a demineralizing solution for 96 hours at 37ºC and 50% relative humidity to create lesions. The demineralized fragments of each tooth were randomly divided into two case (immersed in GSE solution in phosphate buffer for 8 days) and control (immersed in distilled water) groups. The samples were subsequently evaluated using a scanning electron microscope and a micro-hardness tester. Data were analyzed using independent t-test. Results. The mean ± SD micro-hardness values for the case and control groups were 358.6±83.42 and 296.51± 69.41, respectively. Grape seed extract significantly increased the micro-hardness of the lesions (P=0.03). The morphology of GSE treated enamel was clearly different from that in the control group, and there were deposits of scaffolding insoluble complexes on the enamel surface. Conclusion. GSE enhanced the remineralization process of artificial enamel lesions of primary teeth, and thus, might be considered an effective natural agent in non-invasive dentistry.

Effect of zinc sulfate on human primary enamel microhardness: an in vitro study.

OBJECTIVE: The aim of this study was to assess the effect of zinc sulfate on microhardness of human primary enamel. METHOD: Sixteen sound primary molars were sectioned mesiodistally. For each sample one of the sections was randomly immersed in artificial saliva (Biotene, USA) and the other was immersed in artificial saliva which was charged with 10 mg/5 mL concentration of zinc sulfate supplement (Razak Company, Iran) daily. After 24 days (the expected time to use up one 120-mL bottle) the surface microhardness of enamel was measured by knoop hardness test (KH) with Knoop diamond under a 50-gram load for 10 seconds. RESULTS: The mean (+/- SD) microhardness values (KHV) for the tested groups were 320 +/- 49.45 and 357 +/- 36.35, respectively. There were statistically significant differences between the groups as exhibited by independent t-test (P = 0.023). CONCLUSION: Primary teeth immersed in a zinc sulfate rich solution for 24 days showed higher microhardness values in comparison with the control group.