The optical property measuring methods for resin composite using multiple spectrophotometers.

This study aimed to propose the measurement methods for resin composite translucency using four shades of resin composite and four spectrophotometers. Four methods were used for measuring translucency: (A) color measurement using reflectance mode, (B) visible light spectrum measurement using reflectance mode, (C) color measurement using transmittance mode, (D) visible light spectrum measurement using transmittance mode. Although there was a significant difference among the results of the translucency measuring methods, the same tendency was observed for translucency parameters obtained using each spectrophotometer. Therefore, the four methods can potentially be used as translucency measuring methods for resin composite.

Antimicrobial and Anti-Biofilm Activities of the Methanol Extracts of Medicinal Plants against Dental Pathogens Streptococcus mutans and Candida albicans.

Several medicinal plants are ethnomedically used in Korea as agents for treating infection, anti-inflammation, and pain relief. However, beyond typical inhibitory effects on cell growth, little is known about the potential anti-biofilm activity of these herbs, which may help to prevent cavities and maintain good oral health. This study aimed to investigate the antimicrobial and anti-biofilm activities of the methanol extracts of 37 Korean medicinal plants against dental pathogens Streptococcus mutans and Candida albicans, which synergize their virulence so as to induce the formation of plaque biofilms in the oral cavity. The antimicrobial activities were investigated by broth dilution and disk diffusion assay. The anti-biofilm and antioxidant activities were evaluated based on the inhibitory effect against glucosyltransferase (GTase) and the DPPH assay, respectively. Among 37 herbs, eight plant extracts presented growth and biofilm inhibitory activities against both etiologic bacteria. Among them, the methanol extracts (1.0 mg/ml) from Camellia japonica and Thuja orientalis significantly inhibited the growth of both bacteria by over 76% and over 83% in liquid media, respectively. Minimum inhibitory concentration (MIC) values of these methanol extracts were determined to be 0.5 mg/ml using a disk diffusion assay on solid agar media. Biofilm formation was inhibited by more than 92.4% and 98.0%, respectively, using the same concentration of each extract. The present results demonstrate that the medicinal plants C. japonica and T. orientalis are potentially useful as antimicrobial and anti-biofilm agents in preventing dental diseases.

Three new stereoisomers of condensed tannins from the roots of Rosa multiflora.

Three new stereoisomers of condensed tannins (1-3), and four known phenolic compounds (4-7) were isolated from the 80% acetone extract of the roots of Rosa multiflora Thunberg. The structures of these compounds were elucidated using 1D/2D NMR, high resolution (HR)-MS, and circular dichroism (CD) spectra. In order to evaluate their anti-oxidative and anti-inflammatory activities, their 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and inhibitory activity on nitric oxide (NO) production were determined.

The anti-oxidative and anti-inflammatory effects of caffeoyl derivatives from the roots of Aconitum koreanum R. RAYMOND.

Activity guided fractionation of Aconitum koreanum root extract (RAK), a traditional medicine in Korea, afforded four caffeoyl derivatives, caffeic acid (1), 4,5-dicaffeoylquinic acid (2), 3,5-dicaffeoylquinic acid (3) and 3,5-dicaffeoylquinic acid methyl ester (4). In order to evaluate the anti-oxidative and anti-inflammatory effects of these compounds, their 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities and abilities to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 were examined. And the protein and mRNA levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in LPS-stimulated HaCaT cells were also quantified by Western blotting and reverse transcription-polymerase chain reaction (RT-PCR). Compounds (1-4) showed potent DPPH radical scavenging and NO inhibitory activities as compared with positive controls (L-ascorbic acid and N(G)-monomethyl-L-arginine (L-NMMA), respectively). Also, these compounds dose-dependently inhibited the expressions of iNOS and COX-2 as well as their mRNA levels.

Effect of the hydrophilic nanofiller loading on the mechanical properties and the microtensile bond strength of an ethanol-based one-bottle dentin adhesive.

This study evaluated the hypothesis that if hydrophilic nanofillers were dispersed evenly within the adhesive layer under moist conditions, adding them to a one-bottle dentin adhesive might improve the mechanical properties of the adhesive layer, and accordingly increase the bond strength. The flexural strength (FS), the degree of conversion (DC), and the microtensile bond strength (MTBS) to the dentin of four experimental ethanol-based one-bottle dentin adhesives containing 0, 0.5, 1.0, and 3.0 wt % of 12-nm hydrophilic fumed silica were evaluated, and the distribution of the nanofillers were compared using transmission electron microscopy (TEM). Although the nanofiller content did not affect the DC, the FS tended to increase with increasing nanofiller content. The MTBS appeared to increase when up to 1.0 wt % of the nanofillers were added, but they were statistically not significant. However, when 3.0 wt % of the nanofillers were added, the MTBS decreased significantly comparing to the adhesive containing 0.5 wt % nanofillers (p < 0.05). The TEM image suggested that if the nanofillers within the adhesive were 3.0 wt % and applied to a wet dentin surface, they aggregated easily into large clusters and would decrease the MTBS.