Effect of coloring treatment of translucent zirconia on the masking ability of metal abutment / 대한치과재료학회지

Translucent monolithic zirconia is widely used because it has continuously enhanced color and translucency. However, when translucent monolithic zirconia are used for esthetic zone like anterior, it has problem to be exposed to color of titanium abutment. The purpose of this study was to evaluate the effect of coloring and cementing of translucent zirconia on the color masking of titanium abutments. The CIE L*, a*, and b* values were measured using a spectrophotometer in three subgroups after coloring with A2 colorant and white opaque colorant, and the color difference and translucency of each group were analyzed. In the A2 colorant application group, the color difference (ΔE* ) between zirconia and zirconia on titanium abutments was not clinically acceptable (ΔE* > 3.3). In the white opaque group and the white opaque plus A2 colorant group, the color difference (ΔE* ) between zirconia and zirconia on titanium abutments was clinically acceptable (1<ΔE* <3.3). The translucency of zirconia was significantly affected by the coloring treatment (P<.001). The Pearson correlation between color difference and translucency parameters was high (r=0.982, R2 =0.965). The white coloring treatment to translucent zirconia affected masking of titanium abutment. The combination of A2 colorant and white opaque colorant increased the color masking effect of titanium abutments and achieved a shade similar to natural teeth. Resin cement adhesion to translucent zirconia did not affect the color masking of titanium zirconia. As the zirconia translucency increases, it had less of an effect on the titanium abutment.

Anti-Oxidative and Anti-Inflammatory Effects of QGC in Cultured Feline Esophageal Epithelial Cells

Quercetin-3-O-beta-D-glucuronopyranoside (QGC) is a flavonoid glucoside extracted from Rumex Aquaticus Herba. In the present study, anti-oxidative and anti-inflammatory effects of QGC were tested in vitro. Epithelial cells obtained from cat esophagus were cultured. When the cells were exposed to acid for 2 h, cell viability was decreased to 36%. Pretreatment with 50 microM QGC for 2 h prevented the reduction in cell viability. QGC also inhibited the productions of intracellular ROS by inflammatory inducers such as acid, lipopolysaccharide, indomethacin and ethanol. QGC significantly increased the activities of superoxide dismutase (SOD) and catalase, and also induced the expression of SOD2, while it restored the decrease of catalase expression in cells exposed to acid. QGC inhibited NF-kappaB translocation, cyclooxygenase-2 expression and PGE2 secretion in cells exposed to acid, which plays an important role in the pathogenesis of esophagitis. The data suggest that QGC may well be one of the promising substances to attenuate oxidative epithelial cell injury and inflammatory signaling in esophagus inflammation.

Pattern of Methicillin-resistant Staphylococcus aureus in Dental and Medical Environments

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most prevalent pathogens in hospitals. To investigate cross contamination by this bacterium in both dental and medical settings, the pathogens that cause acute pyogenic infection and one of the major microbes responsible for nosocomial infection were isolated from health care providers, nurses and patients. We used VITEK II to measure drug sensitivity, and we further performed biochemical testing, coagulase serotype testing and pulse-field gel electrophoresis (PFGE) for isolated MRSA colonies. The isolation rate of Staphylococcus aureus from nasal swabs was 75.0% from dental health care providers and 18.8% from the medical health care providers. A total of 10 MRSA strains were isolated from 40 health care providers and 2 patients and the prevalent coagulase serotype from patients and health care providers was VII. The antimicrobial drug resistance and partial PFGE types of the isolated MRSA strains showed a similar pattern. These results suggest that MRSA may be one of the principal causes of nosocomial infection in dental and medical hospitals.

Monitoring of Methicillin-resistant Staphylococcus aureus in Nasal Swabs Obtained from Dental Clinic Healthcare Providers and Medical Environment Nurses

The aims of this study were to investigate the nosocomial infection route of methicillin-resistant Staphylococcus aureus (MRSA) and explore preventative methods for this pathogen that involve blocking its dispersion. We cultured MRSA from nasal cavity swabs collected between June and July 2008 that we obtained from eight dental healthcare providers, 32 nurses and the sputum specimens of two patients from our hospital. In addition, we used VITEK 2 equipment to measure drug sensitivity, and we further performed biochemical testing and pulse-field gel electrophoresis (PFGE) to isolate MRSA colonies. The incidence of these bacteria on the nasal swabs was 25.0% from dental clinic healthcare providers, 13.6% from the internal medicine ward nurses and 30.0% from intensive care unit nurses. Moreover, MRSA was detectable in sputum specimens of ward patients. The antimicrobial agents resistance and partial PFGE types of MRSA showed a similar pattern. We suggest from these analyses that nasal cavity infection by MRSA could occur by cross contamination between healthcare providers and patients which underscores the importance of stringent MRSA management practices.