Dentin Staining Caused by Nano-silver Fluoride: A Comparative Study.

CLINICAL RELEVANCE: The new formulations of nano-silver fluoride caused less dentin staining than the already available commercial agents 35% silver fluoride and silver diamine fluoride at 30% and 38%. SUMMARY: The objective of this study was to evaluate the dentin staining potential of nano-silver fluoride (NSF 600 and 1500 ppm) compared with the following commercially available cariostatic agents: Advantage Arrest (Elevate Oral Care, West Palm Beach, FL, USA), Riva Star (SDI, Victoria, Australia), and Cariestop (Biodinâmica, Paraná, Brazil). Seventy-five extracted human molars were sectioned at the cementoenamel junction, and the occlusal enamel was removed for exposure of coronary dentin. The samples were divided among the five agents tested (n=15). The dentin staining (ΔE/ΔL) was analyzed with a digital spectrophotometer (VITA Easyshade, VITA Zahnfabrik, Bad Säckingen, Germany) at three different time points (before application, after two weeks, and after four weeks). Photographic images were also performed. The Kruskal-Wallis and Mann-Whitney tests compared the mean ΔE and ΔL values between groups. The NSF 600 and 1500 ppm resulted in the smallest color change (ΔE=1.02 and 1.53) and dentin staining after four weeks (ΔL=-0.76 and -1.2). The new formulations differed significantly from the commercial cariostatic agents (p<0.001). NSF might be an alternative to silver diamine fluoride since it does not compromise esthetics.

Hydrolytic and Biological Degradation of Bulk-fill and Self-adhering Resin Composites.

OBJECTIVES: This study aimed to evaluate the hydrolytic degradation (in vitro) and biodegradation (in situ) of different resin composites: bulk-fill (XTra Fill, XTF/VOCO; Tetric EvoCeram Bulk Fil, TBF/ Ivoclar Vivadent), self-adhering (Vertise Flow, VTF/ Kerr; Fusio Liquid Dentin, FUS/ Pentron Clinical), and a conventional resin composite (Filtek Z250, Z250/ 3M ESPE), which was used as a control. METHODS AND MATERIALS: Seventy-five cylindrical specimens (7 × 1 mm) were desiccated and immersed into distilled water (DW), artificial saliva (AS), and 0.1 M lactic acid (LA) (n=5) for 180 days. Specimens were weighed after 180 days, after which they were desiccated again. The sorption (µg/mm3) and solubility (µg/mm3) were calculated based on ISO 4049. For the in situ phase, an intraoral palatal device containing five cylindrical specimens (5 × 1.5 mm) was used by 20 volunteers for seven days. Surface roughness was evaluated before and after this period to analyze the superficial biodegradation. Sorption and solubility data were submitted to Kruskal-Wallis and Mann-Whitney tests. The Wilcoxon signed-rank test was used to compare roughness at different observation times. The statistical significance for all tests was considered α=0.05. RESULTS: For in vitro, self-adhering resin composites (VTF and FUS) showed, respectively, higher sorption values independent of the solution (62.55 and 50.81 µg/mm3 in DW, 67.26 and 50.46 µg/mm3 in AS, and 64.98 and 59.86 µg/mm3 in LA). Self-adhering VTF also had a greater solubility value in DW (22.18 µg/mm3) and FUS in LA (65.87 µg/mm3). In AS, the bulk-fill resin composite XTF showed higher solubility (22.13 µg/mm3). All resins were biodegraded, but the XTF specimens were more resistant (p=0.278) to chemical attack. CONCLUSIONS: The self-adhering resin composites showed the highest hydrolytic degradation, and the bulk-fill resin composites exhibited comparable or superior results to the conventional resin composites. Not all resin composites underwent biodegradation in the in situ environment. The storage environment influenced the final characteristics of each material tested.