Influência dos diferentes tratamentos de superfície de pinos de fibra de vidro na resistência de união e análise topográfica

Abstract

This study evaluated the effect of different surface treatments on the morphological aspects of post surface and the adhesion of core materials to glass fiber posts. To evaluate the bond strength 44 fiber posts (White Post DC3, FGM Produtos Odontológicos), were randomly divided into four groups (n = 11). The following surface treatments were evaluated: Control- without surface treatment; MTPS- deposition siloxane; H2O2- etching with hydrogen peroxide at 35% (Whiteness HP Max, FGM Produtos Odontológicos); and CH2Cl2- etching with methylene chloride (Synth). Then, the experimental groups received application of a layer of silane (Prosil, FGM Produtos Odontológicos) and adhesive (Scothbond, 3M Espe). The composite resin restorations (Core Allcem, FGM Produtos Odontológicos) were simulated using silicone molds. After 24 hours water storage at 37°C, the The specimens were serially sectioned to obtain 1 mm-thick consisting of resin/ post/ resin. Microtensile tests were performed at speed of 0.7 mm/min until failure. To measure contact angles water and adhesive was used. Twenty fiber posts were embedded in acrylic resin and polished to flat surface. The samples were divided randomly into four groups (n = 5) and surface treatments performed. A drop (0.3 uL) of water was deposited on the post surface and the contact angle measured with a tensiometer (Theta Lite TL101, Biolin Scientific Inc.). Then, silane was used and the contact angle produced by the adhesive to the treated surface was also measured. To evaluate the surface topography, analysis was performed by laser interferometer (Microfocus Expert IV, UBM). Twenty posts were randomly divided into four groups (n = 5) after the surface treatment. The scanning of samples was performed and evaluated topographic parameters (Ra: arithmetic average roughness profile), (Rq: arithmetic square roughness), (SA: Arithmetic average of three-dimensional roughness) and (Sq: root mean square deviation of surface roughness). For SEM and EDS analysis eight post were divided into four groups (n = 2), after completion of surface treatments. Datas were individually subjected to one-way ANOVA followed by Tukey test. The results demonstrate that the group treated with MTPS, obtained higher bond strength. The contact angle with water, the more hydrophilic surface was observed in the MTPS group. The contact angle with resin adhesive showed lower values for control group. All experimental treatments increased surface roughness. SEM images and EDS analyzes showed changes in surface after different treatments. In conclusion, the siloxane deposition is effective to increase bond strength, while maintaining chemical and morphological change in the fiber post.