ABSTRACT
OBJECTIVES@#To coat a zirconia surface with silica-zirconia using a dip-coating technique and evaluate its effect on resin-zirconia shear bond strength (SBS).@*METHODS@#A silica-zirconia suspension was prepared and used to coat a zirconia surface using a dip-coating technique. One hundred and eighty-nine zirconia disks were divided into three groups according to their different surface treatments (polishing, sandblasting, and silica-zirconia coating). Scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD) were used to analyze the differently treated zirconia surfaces. Different primer treatments (Monobond N, Z-PRIME Plus, and no primer) were also applied to the zirconia surfaces. Subsequently, 180 composite resin cylinders (Filtek Z350) were cemented onto the zirconia disks with resin cement (RelyX Ultimate). The SBS was measured after water storage for 24 h or 6 months. The data were analyzed by two-way analysis of variance (ANOVA).@*RESULTS@#SEM and EDX showed that the silica-zirconia coating produced a porous layer with additional Si, and XRD showed that only tetragonal zirconia was on the silica-zirconia-coating surface. Compared with the control group, the resin-zirconia SBSs of the sandblasting group and silica-zirconia-coating group were significantly increased (@*CONCLUSIONS@#Dip-coating with silica-zirconia might be a feasible way to improve resin-zirconia bonding.
ABSTRACT
<p><b>OBJECTIVE</b>To observe the effect of lipopolysaccharide(LPS) and interleukin-1beta (IL-1beta) on the expression of inducible nitric oxide synthase (iNOS) gene and nitric oxide (NO) in human periodontal ligament cells (hPDLCs).</p><p><b>METHODS</b>After stimulating hPDLCs by LPS and IL-1beta, RT-PCR had been used to identify the expression of iNOS gene. The activity of iNOS in the culture was quantitated by enzyme-linked immune sorbent assay (ELISA). And the level of NO was determined by nitrate reductase method. RESULTS Slight amount of iNOS and NO had been detected in hPDLCs without sitimulation, but when stimulating with LPS and IL-1beta, the amount of the iNOS mRNA increased significantly in the cells in the time and dose dependent way (P<0.05). Under the stimulation with the same time or same dose, the productions of iNOS and NO stimulated by IL-1beta and in combination with LPS were larger than that stimulated with LPS (P<0.05).</p><p><b>CONCLUSION</b>The expression NO and iNOS could be increased by stimulating hPDLCs with LPS and IL-1beta, which may contribute to the research on injecting LPS and IL-1beta at periodontal tissue of animal models.</p>