PURPOSEThis study was to evaluate the marginal fit of two CAD-CAM anatomic contour zirconia crown systems compared to lithium disilicate glass-ceramic crowns.MATERIALS AND METHODSShoulder and deep chamfer margin were formed on each acrylic resin tooth model of a maxillary first premolar. Two CAD-CAM systems (Prettau®Zirconia and ZENOSTAR®ZR translucent) and lithium disilicate glass ceramic (IPS e.max®press) crowns were made (n=16). Each crown was bonded to stone dies with resin cement (Rely X Unicem). Marginal gap and absolute marginal discrepancy of crowns were measured using a light microscope equipped with a digital camera (Leica DFC295) magnified by a factor of 100. Two-way analysis of variance (ANOVA) and post-hoc Tukey's HSD test were conducted to analyze the significance of crown marginal fit regarding the finish line configuration and the fabrication system.RESULTSThe mean marginal gap of lithium disilicate glass ceramic crowns (IPS e.max®press) was significantly lower than that of the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia) (P<.05). Both fabrication systems and finish line configurations significantly influenced the absolute marginal discrepancy (P<.05).CONCLUSIONThe lithium disilicate glass ceramic crown (IPS e.max®press) had significantly smaller marginal gap than the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia). In terms of absolute marginal discrepancy, the CAD-CAM anatomic contour zirconia crown system (ZENOSTAR®ZR translucent) had under-extended margin, whereas the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia) and lithium disilicate glass ceramic crowns (IPS e.max®press) had overextended margins.

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The aim of this study was to evaluate the antibacterial activity against Porphyromonas gingivalis and osteoblast viability of heat and plasma treatment of TiO2 nanotubes. Specimens were divided into four groups: the Ti (polished titanium), Nano (TiO2 nanotube), NH 300 (heat treated at 300 °C on TiO2 nanotube) and NH 400 (heat treated at 400 °C on TiO2 nanotube) groups. Antibacterial activity and osteoblast viability were evaluated in the four groups according to plasma treatment. Surface adhesion of Porphyromonas gingivalis was evaluated by crystal violet assay. Osteoblast viability was examined by XTT assay. Adhesion of Porphyromonas gingivalis was significantly decreased in the Ti group, Nano group and NH 300 group after plasma treatment (P < 0.05). Osteoblast viability was increased in the NH 400 group in comparison to the Ti group before plasma treatment (P < 0.05). Within the limitations of this study, plasma treatment was found to reduce the adhesion of P. gingivalis but had no influence on osteoblast activation.