Examination of bond strength and mechanical properties of Y-TZP zirconia ceramics with different surface modifications.

The purpose of our study was to evaluate the effects of surface modifications on the bond strength between veneering porcelains and Yttria-stabilized tetragonal zirconia (Y-TZP). In a bond strength tests, the effect of control, 70 µm alumina-sandblasting, 30 µm and 110 µm silica-coating of the Y-TZP surface on bonding were evaluated with veneering porcelains. In addition, the effect of surface modification on the flexural strength of Y-TZP was also evaluated. The data was analyzed using one-way ANOVA and Tukey test. All specimens showed bond strength values in excess of 25 MPa, the minimum allowed by ISO9693. In addition, significantly differences were found between the control and the 30 µm silica-coated. On the other hand the flexural strength of Y-TZP does not significantly difference for any surface modification. These results indicate that silica-coating may provide an effective pre-treatment for this enhancement of the bond strength while maintaining the strength of Y-TZP.

Response of human fibroblasts to implant surface coated with titanium dioxide photocatalytic films.

PURPOSE: This study was to develop a titanium dioxide (TiO(2))-coated implant abutment, surface with ultraviolet (UV) light-induced hydrophilicity and investigate the initial response of human, fibroblasts to the surface modification. MATERIALS AND METHODS: Commercially pure titanium (JIS 2 grade) disks were coated with TiO(2) to various, thicknesses (1, 2 or 3 µm) using peroxotitanium acid solution. The surface characteristics of each disk, were examined with X-ray diffraction (XRD), surface roughness equipment and scanning electron, microscopy (SEM). The hydrophilic change of each disk was determined by the contact angles at 0-24h, after 24-h UV irradiation. The biological response at the surface of each disk was examined by using, human periodontal ligament fibroblasts (HPLFs). The data were statistically analyzed with analysis of variance (ANOVA) and multiple-comparison tests. RESULTS: The TiO(2)-coated disk surface had an anatase structure. Surface roughness did not differ, significantly among the disks; the surface morphology was smooth and had a hydrophilic or superhydrophilic, status. HPLF proliferation significantly increased on the TiO(2)-coated disks compared with the uncoated disks and depended upon the coated film thickness. CONCLUSION: An anatase TiO(2)-coated surface under UV irradiation markedly improves the initial response of human fibroblasts.

Bonding strength of autopolymerizing resin to nylon denture base polymer.

This study aimed to investigate the shear bond strength of an autopolymerizing resin to a nylon denture base polymer (Lucitone FRS: LT) subjected to different surface treatments, and the results thereof compared with a heat-polymerizing resin and a polycarbonate polymer. Specimens were divided into five groups according to the surface treatment method: polishing (#600), sandblasting, adhesive primer application (resin primer), sandblasting + adhesive primer application, and tribochemical coating (Rocatec system). Following which, specimens were subjected to a shear bond strength test and Si concentrations were measured using an electron probe microanalyzer (EPMA). On shear bond strength, that of LT with tribochemical coating was significantly higher than the other groups. On EPMA results, the surface of LT with tribochemical coating was found to be covered with a silica film. Therefore, findings in this study indicated that silica-coating by Rocatec system was effective in improving the bond strength of nylon denture base polymer to autopolymerizing repair resin.

Influence of simplified silica coating method on the bonding strength of resin cement to dental alloy.

This study evaluated the effectiveness of a simplified silica coating method (CoJet System) on the bonding strength of resin cements to dental alloy. Bonding strength of the specimens treated with metal primer after alumina sandblasting was compared with those treated with silica coating and silane coupling agent after alumina sandblasting. Furthermore, the influence of silane coupling agent on bonding strength was compared between one-liquid and two-liquid silane coupling agents. Measurement of shear bond strength before and after thermal cycling revealed that the group treated with silica coating in one step without alumina sandblasting yielded high bonding strength. As for the influence of silane coupling agent, treatment with two-liquid silane coupling agent achieved higher mean shear bond strength than with one-liquid silane coupling agent. Findings in this study indicated that silicatization by means of this simplified silica coating method was effective in improving the bonding strength to dental alloy.

Durability of FTLA treatment as a medicament for dentin hypersensitivity--abrasion resistance and profiles of fluoride release.

The purpose of this study was to evaluate the durability of tubules occluded with FTLA treatment by toothbrush abrasion test on the applied surface and by measuring fluoride release from the FTLA components. Dentin specimens with simulated hypersensitive surfaces were treated with APF containing tannic acid. After which, the specimens received lanthanum-chloride-with-powdered-fluoroapatite-glass-ceramics treatment. The specimens were subjected to toothbrush abrasion test up to 6,000 strokes. SEM observation revealed that dentinal tubules of the FTLA treated specimens were completely occluded with fine deposits even after toothbrush abrasion of 6,000 strokes. EPMA analysis revealed that fluoride, lanthanum, and aluminum were the main FTLA components on the dentin surface after 6,000-stroke abrasion. To measure fluoride release from the FTLA components, a slurry was enclosed in a cellulose tube and suspended in deionized water at 37 degrees C. After fluoride was dialyzed against deionized water, a high concentration of fluoride was found to be released from FTLA the components, indicating FTLA treatment's prominent durability. These results suggested that FTLA treatment has a superior resistance against toothbrush abrasion and a high fluoride-releasing performance. These characteristics lend much weight to showing that the FTLA method is an effective and durable medicament for dentin hypersensitivity.