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Abstract: Objectives: The aim of this study was to functionalize the surface of yttria partially stabilized tetragonal zirconia ceramics (Y-TZP) with a nano-structured alumina coating to improve resin bonding. Materials and methods: A total of 120 densely sintered disc-shaped specimens (15.5±0.03mm in diameter and 2.6±0.03mm thick) were produced from biomedical-grade TZ-3YB-E zirconia powder (Tosoh, Tokyo, Japan), randomly divided into three groups of 40 and subjected to the following surface treatments: AS – as-sintered; APA – airborne-particle abraded; POL – polished. Half of the discs in each group received an alumina coating that was fabricated by exploiting the hydrolysis of aluminium nitride (AlN) powder (groups AS-C, APA-C, POL-C). The coating was characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The shear-bond strength of the self-etching composite resin (RelyX Unicem, 3M ESPE, USA) was then studied for the coated and uncoated surfaces of the as-sintered, polished and airborne-particle abraded specimens before and after thermocycling (TC). Results: The SEM/TEM analyses revealed that the application of an alumina coating to Y-TZP ceramics created a highly retentive surface for resin penetration. The coating showed good surface coverage and a uniform thickness of 240nm. The resin-bond strength to the groups AS-C, APA-C, POL-C was significantly higher than to the groups AS, APA and POL, both before and after TC (p ≤0.05). During TC all the specimens in the POL and AS groups debonded spontaneously. In contrast, the TC did not affect the bond strength of the AS-C, POL-C and APA-C groups. Significance: A non-invasive method has been developed that significantly improves resin-bond strength to Y-TZP ceramics. After surface functionalization the bond survives thermocycling without reduction in strength. The method is relatively simple and has the potential to become an effective conditioning method for zirconia ceramics. [Copyright &y& Elsevier]

The article presents a clinical study on evaluating the shock absorbability between high-abrasion-resistance-posterior resin teeth and commercial porcelain teeth in Japan. A free drop-ball test with an accelerometer was used to test the shock absorbability of commercially available posterior teeth. Several results include the maximum acceleration of porcelain teeth than resin teeth, porcelain teeth shows the shortest duration, and resin teeth shows excellent resistance impact force.

The article presents a study conducted in Japan which examined the effect of pickling on the constitution and color of high-functional gold alloy and porcelain fusing strength with bonding porcelain during the fabrication process. It looks into the involvement of four conditions on the analysis for the constitution and color and for the porcelain fusing strength. The study depicted several results and suggested the usage of the obtained data to alleviate metal allergy.

The article focuses on a study conducted in Japan which investigated the thermal properties of double laminated specimens made from all ceramic and resin cement. The thermal properties of all ceramic specimens were measured by TC-2000 L with a xenon flash as the light source to clarify the changes of thermal properties. It analyzes the thermal conductivity of all ceramic restoratives and human tooth that were calculated. One result shows less thermal conductivity of all ceramic restoratives.

The article presents a study on the on the utilization of a Computer Color Matching system based on the CIBA-Q method for an all ceramics crown, IPS-Empress and the evaluation of the color reproductibility in Japan. The study found out that the reflectance curves of CCM samples were very similar to that of the target ones. It shows that the dL* was higher than dC* where, both coordinates tended to be small if of low translucency target.