Avaliação da resistência de união de um cimento resinoso a um filme vitrocerâmico depositado em superfície de Y-TZP

Abstract

The use of Y-TZP for dental ceramics strengthening has expanded significantly its mechanical properties, allowing its use in various clinical situations such as intraradicular, crowns, fixed partial dentures and implants. With the development of these new ceramic systems the use of traditional methods for surface treatment have been observed to be ineffective since its action occurs on the glassy matrix, nearly non-existent in these ceramics. The objective of this study was to evaluate the bond strength, through a microtensile bond strength test and scanning electron microscopy, of a dual resin cement (Panavia F, Kuraray Co, Japan) of a Zirconia reinforced ceramic (VITA In Ceram Zirconia Y-TZP; VITA Zahnfabrik, Bad Saackingen, Germany), varying the surface treatment method: 1 - Application of ceramic film deposition by Bioactive Glass (VBA), 2-sandblasting with particles of aluminum oxide coated with silica (Rocatec System, 3M-ESPE). Three blocks of pre-sintered ceramic In-Ceram Zirconia YZ were cut into a cutting machine (Isomet 1000, Buehler, USA) producing specimens with 5x6x6mm, which were polished until #1200SiC paper. Composite resin blocks of Filtek Z-350 (3M/ESPE), at the same size, were produced and cemented with Panavia F after the following ceramic treatments: 1 - blasting with 110μm Al₂O₃, with silica system Rocatec (3M/ESPE) and silanization; 2 - deposition of ceramic film and silanization. The cemented blocks were stored in saline (NaCl 0.9%) at 37°C for 7 days and then sliced in the cutting machine to produce sticks with an adhesive area of approximately 0.6mm2 and tested under tension in a universal testing machine (Kratos, São José dos, PR) with a crosshead speed of 0.5mm/min. Fractured samples were gold sputter coated and analyzed by scanning electron microscopy. Collected data were analyzed by T-Student test, showing that group 2 showed bond strength (26.1 ± 4.9) significantly higher than control group 1 (13.3 ± 6.8), p=0.001. SEM analysis showed the predominance of adhesive fractures and cohesive in the cement for the control group and mixed fractures and cohesive in the cement and resin block. The microtensile bond strength to the ceramic film is statistically superior to the method of silicatization by Rocatec, and this fact is correlated with better chemical interaction mediated by the process of silanization at the surface of zirconia modified by ceramic film. The application of film seems to be efficient and should be further investigated for final results.