Adhesion between dental ceramic and bonding resin: Quantitative evaluation by Vickers indenter methodology

Objectives The purpose of this study was to evaluate the adhesion to dental ceramic by Vickers indenter methodology. This technique allows the creation of adhesive fractures and determines the influence of the surface treatment on adhesive capacities. Methods A single bond adhesive system (One Step® Bisco) was applied to ceramic Vitapan 3D Master CE 0124 samples. Ceramic samples were polished with 500 or 4000-grit paper, sandblasted or not (Sa/NSa), treated with fluorhydric acid or not (A/NA) and silane or not (Si/NSi). The experimental groups (Gr) were: (Gr 1) 4000; (Gr 2) 4000 + Si; (Gr 3) 4000 + Sa + A; (Gr 4) 4000 + Sa + A + Si; (Gr 5) 500 + Sa + A + Si. Each sample was indented with the diamond Vickers indenter Leitz Durimet 2 (Wetzlar, Germany) using a load of 20 N for 30 s. The surfaces of the debonded areas were observed in an optical microscope providing a digital image of the debonded surface. The adhesion bond strength was calculated according to the formula of Engel and Roshon [Engel PA, Roshon DD. Indentation-debonding of an adhered surface layer. J Adhesion 1979;10(33): 237–53]. The statistical analysis was conducted using Studentʹs t test (p < 0.05). Results The values obtained for each group were: (Gr 1) 32 MPa; (Gr 2) 52 MPa; (Gr 3) 112 MPa; (Gr 4) 131 MPa; (Gr 5) 265 MPa. There is a significant improvement in bond strength with the silane application on the 4000 polished surface (Gr 2). However, there is no significant difference when silane is applied or not on a sanded and etched ceramic (Gr 4). Bond strengths were higher with 500 grit polished, sanded, etched with silane application on the surface (Gr 5). Significance The Vickers indenter methodology is able to discriminate between the influences of different surface treatments on the adhesion of an adhesive layer on a feldspathic ceramic.