Efeito de diferentes protocolos de jateamento sobre a durabilidade de união de uma cerâmica ao cimento resinoso

Abstract

This study evaluated the wettability, surface morphology and the influence of thermocycling on the bond strength of a resin cement and a zirconia ceramic stabilized by yttrium (Y-TZP) under different blasting protocols. Were made 35 discs (diameter: 15mm, thickness: 2 mm) sintered ceramic LAVA All-Ceramic System (3M Espe - Seefeld - Germany). The discs were randomly divided (n = 5): A45 - blasting Al2O3 45μm; A80 - blasting Al2O3 80μm; C30 - blasting Al2O3 coated SiO2 30μm (Cojet); R30 - Blasting Al2O3 coated SiO2 30μm (Rocatec Soft); R110 - blasting Al2O3 coated SiO2 110μm (Rocatec Plus); R110R30 - R110 + R30; ST - untreated. The blast was standardized in the constant pressure 2,5bars, distance 10mm, circular motion during 90s. For the shear test with and without cycling (n = 10) on the ceramic disc already fixed in the cylinder of acrylic resin were placed with wax utility four cylindrical transparent matrices (Tygon tubing, TYG-030, Saint-Gobain PerformancePlastic, Maime Lakes, FL, USA - 3 mm internal diameter by 3 mm height). The ceramic surfaces were silanized for 60 seconds (Monobond S-Ivoclar-Vivadent- Schaan-Liechtenstein) with microbrush (Vigodent, Rio de Janeiro, RJ, Brazil) internally to tygon tubing in zirconia actively for 60 seconds, and held drying with light air jet for 20 seconds. Were filled with Panavia F ® (Kuraray, Okayama, Japan) with the aid of a syringe with tip centrix (AccuDose needle) (Polidental Ind. E Com. Ltda- São Paulo-SP, Brazil). The curing was performed with the LED-Cal Radii (SDI-Pine-SP, Brazil) with an intensity of 1200mW / cm and polymerization time of 40 seconds. After stored in distilled water in the oven (Olidef- Ribeirão Preto - São Paulo-Brazil), at 37 ° C for 24 hours, the arrays were removed with the help of number 12 scalpel blades (Becton Dickinson-New Jersey-US). After this period half of the samples were subjected to 3,000 cycles of thermal cycling in a thermal cycler (Ethics Scientific Equipment S / Sao Paulo-A- Brazil). The other half, was later taken to the shear test (EMIC DL-2000 - São José dos Pinhais, Paraná). For statistical analysis we used the ANOVA (two factors) and Tukey (α = 0.05). Then the fractured surface was inspected in stereo (Discovery.V20, Carl Zeiss, LLC, USA) (n = 2) with magnification 9X. The fracture mode was classified into three different types: Adhesive, Mixed and Cohesive. Two discs over each group (n = 2) had their blasted surfaces and observed (2000x) in Scanning Electron Microscope FEI INSPECT S50 (Brno, Czech Republic). The contact angle was measured by goniometer (Rame-Hart, Inc., 100-00, Contact Angle Goniometers -. Montain Lakes - USA) (n = 5) in each sample before and after blasting protocol. A drop of distilled water was placed on the ceramic surface with a syringe and the contact angle was measured 20 seconds (30 frames per second). Statistical analysis was performed using ANOVA (one factor) and Tukey (α = 0.05). It was observed that in the absence of thermal cycling, the surface treatment did not influence the bond strength (p = 0.238). A80 group (12.42 ± 4.08); A45 (14.38 ± 4.95); C30 (16.86 ± 4.53); R30 (13.99 ± 5.55); R110 (14.02 ± 5.03); R110R30 (11.75 ± 4.19); ST (10.57 ± 4.10). Thermocycling influence the bond strength values of all the groups (p = 0.399). The higher bond strength values were obtained after thermocycling for the A80 groups (4,927bc ± 1.53) and R110 (7,175bc ± 1.34) compared with the ST group (1,86e ± 0.30) , C30 (2,132e ± 0.73) and R110R30 (3,251de ± 1.37). For all the samples analyzed were considered failures adhesive. The photomicrographs illustrate more homogeneous surfaces for the groups with smaller angles C30 (62.6; of ± 0.91), R30 (61,91e ± 1.05) and R110R30 (61,54e ± 1.02). The blasting statistically influence the value of the contact angle, where the ST group (110,61a ± 0.90) had a higher 13 angle and R110R30 groups (1.02 ± 61,54e), R30 (61,91e ± 1.05 ), C30 (62,66de ± 0.91) and A45 (65,50d ± 0.94) had the lowest angles respectively. It follows that the blasting C30, R30 and R110R30 provided higher wettability of the surface of the studied ceramics. The highest bond strength values were for the groups where they underwent blasting with aluminum oxide 80μm and Rocatec 110 microns. Despite this union will not be durable. Although larger particles causing greater damage to the ceramic surface, produce higher bond strength values. The silica coating blasting protocol with larger particles was the treatment that promoted while higher wettability and higher bond strength.