The effect of plasma on shear bond strength between resin cement and colored zirconia

PURPOSE: To investigate the effect of non-thermal atmospheric pressure plasma (NTAPP) treatment on shear bond strength (SBS) between resin cement and colored zirconia made with metal chlorides. MATERIALS AND METHODS: 60 zirconia specimens were divided into 3 groups using coloring liquid. Each group was divided again into 2 sub-groups using plasma treatment; the experimental group was treated with plasma, and the control group was untreated. The sub-groups were: N (non-colored), C (0.1 wt% aqueous chromium chloride solution), M (0.1 wt% aqueous molybdenum chloride solution), NP (non-colored with plasma), CP (0.1 wt% aqueous chromium chloride solution with plasma), and MP (0.1 wt% aqueous molybdenum chloride solution with plasma). Composite resin cylinders were bonded to zirconia specimens with MDP-based resin cement, and SBS was measured using a universal testing machine. All data was analyzed statistically using a 2-way ANOVA test and a Tukey test. RESULTS: SBS significantly increased when specimens were treated with NTAPP regardless of coloring (P<.001). Colored zirconia containing molybdenum showed the highest value of SBS, regardless of NTAPP. The molybdenum group showed the highest SBS, whereas the chromium group showed the lowest. CONCLUSION: NTAPP may increase the SBS of colored zirconia and resin cement. The NTAPP effect on SBS is not influenced by the presence of zirconia coloring.

Influence of preparation depths on the fracture load of customized zirconia abutments with titanium insert

PURPOSE: This study evaluated the fracture load of customized zirconia abutments with titanium insert according to preparation depths, with or without 5-year artificial aging. MATERIALS AND METHODS: Thirty-six identical lithium disilicate crowns (IPS e.max press) were fabricated to replace a maxillary right central incisor and cemented to the customized zirconia abutment with titanium insert on a 4.5x10 mm titanium fixture. Abutments were fabricated with 3 preparation depths (0.5 mm, 0.7 mm, and 0.9 mm). Half of the samples were then processed using thermocycling (temperature: 5-55degrees C, dwelling time: 120s) and chewing simulation (1,200,000 cycles, 49 N load). All specimens were classified into 6 groups depending on the preparation depth and artificial aging (non-artificial aging groups: N5, N7, N9; artificial aging groups: A5, A7, A9). Static load was applied at 135 degrees to the implant axis in a universal testing machine. Statistical analyses of the results were performed using 1-way ANOVA, 2-way ANOVA, independent t-test and multiple linear regression. RESULTS: The fracture loads were 539.28 +/- 63.11 N (N5), 406.56 +/- 28.94 N (N7), 366.66 +/- 30.19 N (N9), 392.61 +/- 50.57 N (A5), 317.94 +/- 30.05 N (A7), and 292.74 +/- 37.15 N (A9). The fracture load of group N5 was significantly higher than those of group N7 and N9 (P<.017). Consequently, the fracture load of group A5 was also significantly higher than those of group A7 and A9 (P<.05). After artificial aging, the fracture load was significantly decreased in all groups with various preparation depths (P<.05). CONCLUSION: The fracture load of a single anterior implant restored with lithium disilicate crown on zirconia abutment with titanium insert differed depending on the preparation depths. After 5-year artificial aging, the fracture loads of all preparation groups decreased significantly.

Evaluation of marginal fit of 2 CAD-CAM anatomic contour zirconia crown systems and lithium disilicate glass-ceramic crown

PURPOSE: This 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 METHODS: Shoulder and deep chamfer margin were formed on each acrylic resin tooth model of a maxillary first premolar. Two CAD-CAM systems (Prettau(R)Zirconia and ZENOSTAR(R)ZR translucent) and lithium disilicate glass ceramic (IPS e.max(R)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. RESULTS: The mean marginal gap of lithium disilicate glass ceramic crowns (IPS e.max(R)press) was significantly lower than that of the CAD-CAM anatomic contour zirconia crown system (Prettau(R)Zirconia) (P<.05). Both fabrication systems and finish line configurations significantly influenced the absolute marginal discrepancy (P<.05). CONCLUSION: The lithium disilicate glass ceramic crown (IPS e.max(R)press) had significantly smaller marginal gap than the CAD-CAM anatomic contour zirconia crown system (Prettau(R)Zirconia). In terms of absolute marginal discrepancy, the CAD-CAM anatomic contour zirconia crown system (ZENOSTAR(R)ZR translucent) had under-extended margin, whereas the CAD-CAM anatomic contour zirconia crown system (Prettau(R)Zirconia) and lithium disilicate glass ceramic crowns (IPS e.max(R)press) had overextended margins.

Evaluation of antibacterial activity and osteoblast-like cell viability of TiN, ZrN and (Ti(1-x)Zr(x))N coating on titanium

PURPOSE: The aim of this study was to evaluate antibacterial activity and osteoblast-like cell viability according to the ratio of titanium nitride and zirconium nitride coating on commercially pure titanium using an arc ion plating system. MATERIALS AND METHODS: Polished titanium surfaces were used as controls. Surface topography was observed by scanning electron microscopy, and surface roughness was measured using a two-dimensional contact stylus profilometer. Antibacterial activity was evaluated against Streptococcus mutans and Porphyromonas gingivalis with the colony-forming unit assay. Cell compatibility, mRNA expression, and morphology related to human osteoblast-like cells (MG-63) on the coated specimens were determined by the XTT assay and reverse transcriptase-polymerase chain reaction. RESULTS: The number of S. mutans colonies on the TiN, ZrN and (Ti(1-x)Zr(x))N coated surface decreased significantly compared to those on the non-coated titanium surface (P<0.05). CONCLUSION: The number of P. gingivalis colonies on all surfaces showed no significant differences. TiN, ZrN and (Ti(1-x)Zr(x))N coated titanium showed antibacterial activity against S. mutans related to initial biofilm formation but not P. gingivalis associated with advanced periimplantitis, and did not influence osteoblast-like cell viability.

Evaluation of antibacterial activity and osteoblast-like cell viability of TiN, ZrN and (Ti(1-x)Zr(x))N coating on titanium

PURPOSE: The aim of this study was to evaluate antibacterial activity and osteoblast-like cell viability according to the ratio of titanium nitride and zirconium nitride coating on commercially pure titanium using an arc ion plating system. MATERIALS AND METHODS: Polished titanium surfaces were used as controls. Surface topography was observed by scanning electron microscopy, and surface roughness was measured using a two-dimensional contact stylus profilometer. Antibacterial activity was evaluated against Streptococcus mutans and Porphyromonas gingivalis with the colony-forming unit assay. Cell compatibility, mRNA expression, and morphology related to human osteoblast-like cells (MG-63) on the coated specimens were determined by the XTT assay and reverse transcriptase-polymerase chain reaction. RESULTS: The number of S. mutans colonies on the TiN, ZrN and (Ti(1-x)Zr(x))N coated surface decreased significantly compared to those on the non-coated titanium surface (P<0.05). CONCLUSION: The number of P. gingivalis colonies on all surfaces showed no significant differences. TiN, ZrN and (Ti(1-x)Zr(x))N coated titanium showed antibacterial activity against S. mutans related to initial biofilm formation but not P. gingivalis associated with advanced periimplantitis, and did not influence osteoblast-like cell viability.