Patients with facial prostheses suffer from yeast, Candida albicans, infections. This study aimed to determine the biocompatibility and antifungal properties of silicone facial prostheses coated with silver nanoparticles (Ag NPs) in vitro. Medical grade silicone discs were coated with 5 and 50 mg L dispersions of either Ag NPs or AgNO . Coatings were fully characterized using scanning electron microscopy and energy dispersive X-ray spectroscopy. The biocompatibility was examined using human dermal fibroblasts (Hs68), whereas antifungal efficacy was tested against C. albicans (NCPF-3179). The fibroblast viability was assessed by measuring lactate dehydrogenase (LDH) activity, protein content and tissue electrolytes. There were no effects on the LDH activity of fibroblast cell homogenates, and leak of LDH activity into external media remained low (0.1-0.2 IU mL ). Sublethal effects of Ag NP coatings on membrane permeability/ion balance was not observed, as measured by stable homogenate Na and K concentrations. Some Ag (13 mg L ) was detected from the AgNO coatings in the media, but total Ag remained below detection limit (<1.2 µg L ) for the Ag NP coatings; indicating the latter were stable. When fibroblasts grown on silver coatings were challenged with C. albicans, the Ag NP coating was effective at preventing fungal growth as measured by ethanol production by the yeast, and without damaging the fibroblasts. Ethanol production decreased from 43.2 ± 25.02 in controls to 3.6 µmol mL in all the silver treatments. Data shows that silicone prosthetic materials coated with Ag NPs are biocompatible with fibroblast cells in vitro and show antifungal properties. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1038-1051, 2018.

(1) Background: This study compares the antibacterial effect of coated and impregnated flexible dentures with magnesium oxide nanoparticles (MgONPs) against Streptococcus mutans. (2) Methods: the study used flexible denture material discs. The experimental groups were uncoated dics (control), 5% MgONPs coated discs (coated), and 5% MgONPs impregnated discs (impregnated). The homogenous distribution of MgONPs within the matrix was determined using scanning electron microscopy (SEM), and surface roughness and modulus elasticity were also measured. The antibacterial efficacy was tested against Streptococcus mutans in suspension and biofilm. The adhesion of microorganisms was assessed using an adherence assay test, optical light microscopy, and turbidity test. (3) Results: The nanoparticles were successfully coated or impregnated on the substrate and caused a significant increase in roughness. The effect of 5% MgONPs was significant (p < 0.05). The flexible denture samples whether coated or impregnated with 5% MgONPs effectively inhibited the growth of microorganisms. The Streptococcus mutans growth was 2.5 folds higher in control compared to coated samples, while Streptococcus mutans growth was 1.5 folds higher in control compared to impregnated samples. Furthermore, this study confirmed there was a homogenous distribution of MgONPs for both coated and impregnated groups. (4) Conclusions: It was found that addition of 5% MgONPs can prevent the attachment of Streptococcusn mutans to flexible removable denture material. Additionally, the antibacterial effect was higher in the coated-samples compared to impregnated-samples.

(1) Background: The aim of this research was to investigate the antibacterial activity of dissolved silver from silver-coated titanium implants against Streptococcus mutans. (2) Methodology: Silver-coated titanium implant discs were immersed in 1.8 mL of brain heart infusion broth (BHIB) and incubated for 24 h in order to release the silver ions into the broth. The coating quality was confirmed via EDS, and the dissolved silver was measured via inductively coupled plasma mass spectrometry (ICP-MS). The experimental design used unconditioned broth (control) and broth conditioned with silver released from silver-coated titanium implants (n = 6). Regarding the antibacterial activity, isolated Streptococcus mutans was used. A turbidity test and lactate production test were performed to determine the effect of dissolved silver on bacterial growth in a suspension and biofilm formation. (3) Result: The results showed that the coating was successfully applied on the substrate. There was around 0.3 mg/L of silver released into the BHIB, and the turbidity of the control group was significantly higher than the treatment, with measured absorbance values of 1.4 and 0.8, respectively, indicating that the dissolved silver ions from the silver-coated titanium discs exhibited some degree of antibacterial activity by preventing the growth of Streptococcus mutans. However, the results of the antibiofilm activity test did not show any significant difference between the groups. (4) Conclusion: The dissolved silver from silver-coated titanium implants has an antibacterial activity but not a significant antimicrobial activity, indicating that the dissolved silver from silver-coated titanium abutments can significantly reduce the incidence of peri-implant mucositis.

Background and Objective:The objective of the study was to compare the bonding strength between silicone elastomer and two types of framework materials (acrylic resin and metal chrome cobalt) with different surface characterization. Methods A-2186 silicone elastomer was bonded with A-330-G primer to two group of framework materials (acrylic resin and metal chrome cobalt). Each group was subdivided into 4 different surface characterization (Polished surface as a control, Sandblasted surface by aluminum oxide media 250 micron, Polished surface with retentive holes, Surface with retentive holes and sandblasted by aluminum oxide media 250 micron). The samples were prepared with the dimension of (75x 10x 3 mm). All the test groups were subjected to 1800 peel strength test on Hounsfeild universal testing machine (HT-400). The test was carried out according to the ASTM D-903 specifications. The obtained results were then subjected to statistical analysis using Stat Graph 5.1 and the statistical significance was set at 5% level of significance. Result The result showed no significant difference between polished acrylic and sandblasted acrylic surface. However, a significant improvement in bonding strength was observed when acrylic surface was grooved with retentive holes (with and without sandblast surface characterization). However, a significant effect was seen when the surface of metal chrome cobalt was sandblasted with aluminum oxide media compared to polished metal. Additionally, grooves also improved the bonding strength. Furthermore, superior effects were seen when the grooves where sandblasted. Lastly, Intergroup comparison showed superior bonding strength between metal chrome cobalt and silicone compared to acrylic resin and silicone for all surface characterization. Conclusion Within the limitations of the present study, it can be concluded that: There is no significant difference when acrylic surface was sandblasted. However, retentive holes improved the bonding strength between acrylic and silicone. While sandblast improved the bonding strength between metal and silicone elastomer. Lastly, metal bond better to silicone than acrylic resin for all tested groups.