Effect of niobium nitride on the bonding strength of titanium porcelain by magnetron sputtering / 中华口腔医学杂志

<p><b>OBJECTIVES</b>To investigate the effect of magnetron sputtered niobium nitride (NbN) on the bonding strength of commercially pure cast titanium (Ti) and low-fusing porcelain (Ti/Vita titankeramik system).</p><p><b>METHODS</b>Sixty Ti specimens were randomly divided into four groups, group T1, T2, T3 and T4. All specimens of group T1 and T2 were first treated with 120 microm blasted Al2O3 particles, and then only specimens of group T2 were treated with magnetron sputtered NbN film. All specimens of group T3 and T4 were first treated with magnetron sputtered NbN film and then only specimens of group T4 were treated with 120 microm blasted Al2O3 particles. The composition of the deposits were analyzed by X-ray diffraction (XRD). A universal testing machine was used to perform the three-point bending test to evaluate the bonding strength of Ti and porcelain. The microstructure of NbN, the interface of Ti-porcelain and the fractured Ti surface were observed with scanning electron microscopy (SEM) and energy depressive spectrum (EDS), and the results were compared.</p><p><b>RESULTS</b>The XRD results showed that the NbN deposits were cubic crystalline phases. The bonding strength of Ti and porcelain in T1 to T4 group were (27.2+/-0.8), (43.1+/-0.6), (31.4+/-1.0) and (44.9+/-0.6) MPa. These results were analyzed by one-way analysis of variance and differences between groups were compared using least significant difference test. Significant inter-group differences were found among all groups (P<0.05). The results of SEM showed that with treatment of Al2O3 or NbN, alone, pre-cracks were found in the interface of Ti-porcelain, while samples treated with both Al2O3 and NbN had better bond. EDS of Ti-porcelain interface showed oxidation occurred in T1, T2 and T3, but was well controlled in T4.</p><p><b>CONCLUSIONS</b>Magnetron sputtered NbN can prevent Ti from being oxidized, and can improve the bonding strength of Ti/Vita titankeramik system. Al2O3 blast can also improve the bonding strength of Ti/Vita titankeramik system.</p>

Induction of apoptosis and related genes by five kinds of dental materials on L929 cell / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate a new type of diatomite-based machinable ceramic biocompatibility by studying its induced apoptosis on L929 cell in contrasted with other prosthodontics materials.</p><p><b>METHODS</b>Cell line was treated with extracting liquid containing different concentrations of diatomite-based machinable ceramic and other materials. Flow cytometry tested cell cycle progression and induced cell apoptosis. Annexin V-FITC/PI apoptosis staining kit quantitative detected cell death patterns. The expression of Bcl-2 and Bax mRNA were determined by reverse transcription-polymerase chain reaction.</p><p><b>RESULTS</b>The experimental groups had no special influence on cell cycle. Apoptosis rates of the new ceramic closed to the negative group (P > 0.05). The apoptosis rate of resin was the highest, and the cell necrosis level of resin was increased, which had significant difference to the new ceramic (P < 0.05). The Bcl-2 and Bax mRNA levels of the new ceramic and the negative group were closed to each other, which had no statistical significance (P > 0.05).</p><p><b>CONCLUSION</b>The new diatomite-based machinable ceramic has no apparent cytotoxicity, which is consistent with the clinical application of the basic requirements of biocompatibility.</p>

Effects of magnetron sputtered ZrN on the bonding strength of titanium porcelain / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of magnetron sputtered ZrN on the bonding strength between a low-fusing porcelain (Ti/Vita titankeramik system) and commercially pure cast titanium.</p><p><b>METHODS</b>Sixteen specimens were randomly assigned to test group and control group (n=8). The control group received no surface treated. Magnetron sputtered ZrN film was deposited on the surface of specimens in the test group. Then the sixteen titanium-porcelain specimens were prepared in a rectangular shape and went through three-point bending test on a universal test machine. The bond strength of Ti/porcelain was recorded. The phase composition of the specimens was analyzed using X-ray diffraction (XRD). The interface at titanium and porcelain and the titanium surface after debonding were observed with a scanning electron microscopy (SEM) and analyzed using energy depressive spectrum (EDS).</p><p><b>RESULTS</b>New phase of ZrN was found with XRD in the test group. Statistical analysis showed higher bond strength following ZrN surface treatment in the test group [(45.991+/-0.648) MPa] than that in the control group [(29.483+/-1.007) MPa] (P=0.000). Bonded ceramic could be observed in test group, the amount of bonded ceramic was more than that in the control group. No obvious bonded ceramic in control group was found.</p><p><b>CONCLUSIONS</b>Magnetron sputtered ZrN can improve bond strength of Ti/Vita titankeramik system significantly.</p>

Effect of silicon coating on bonding strength of ceramics and titanium / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study investigated the effect of silicon coating (SiO2) by solution-gelatin (Sol-Gel) technology on bonding strength of titanium and ceramics.</p><p><b>METHODS</b>Sixteen pure titanium specimens with the size of 25 mm x 3 mm x 0.5 mm were divided into two groups (n=8), test group was silicon coated by Sol-Gel technology, the other one was control group. The middle area of the samples were veneered with Vita Titankeramik system, the phase composition of two specimens were characterized by X-ray diffraction (XRD). The bonding strength of titanium/porcelain was evaluated using three-point bending test. The interface of titanium and porcelain and fractured titanium surface were investigated by scanning electron microscope (SEM) with energy depressive spectrum (EDS).</p><p><b>RESULTS</b>Contents of surface silicon increased after modification with silicon coated by Sol-Gel technology. The mean bonding strength of test group and control group were (37.768 +/- 0.777) MPa and (29.483 +/- 1.007) MPa. There was a statistically significant difference (P=0.000) between them. The bonded ceramic boundary of test group was wider than control group.</p><p><b>CONCLUSION</b>Silicon coating by Sol-Gel technology was significant in improving bonding strength of titanium/Vita Titankeramik system.</p>