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Meral, YE. Hacettepe University Institute of Health Sciences, Ph.D. Thesis in Prosthodontics, Ankara, 2015. The Effects of Various Surface Treatments for Laminate Veneer Indicated CAD/CAM Block Materials of Feldspathic, Nanocomposite and Hybrid Ceramic on Shear Bond Strength to Enamel. The purpose of this in-vitro study was to assess the effects of various surface treatments, on the surface roughness, shear bond strength to enamel and failures modes of different CAD/CAM block materials that have laminate veneer indications. The surface treatments were grouped as follows: (1) grinding with 125 grit silicone carbide sandpaper, (2) Nd:YAG laser treatment, (3) etching with 4% hydrofluoric acid, (4) etching with 9.5% hydrofluoric acid, (5) air particle abrasion with 110 μm Al2O3, and (6) tribochemical treatment with 30 μm silica coated Al2O3. Surface roughness measurements were performed with a profilometer on 6x6x1 mm specimens. 180 caries-free and sound human maxillary central and lateral incisors were randomly distributed into 18 groups (n=10). After embedding into acrylic resin, intaglio surfaces were prepared on enamel. 4x4x2 mm specimens were prepared from each CAD/CAM block material and tested surface treatments were applied to the cementation surfaces. Bonding to enamel was achieved with a dual-cure adhesive resin cement application. Samples were stored in 37°C distilled water for 24 hours, and shear bond strengths were experimented. Fracture strengths were experimented with of 1.0 mm/min, till the debonding load is reached. The debonded surfaces, both on specimen and enamel, were observed with a 3X loop and modes of failures were determined as adhesive, mixed and cohesive. Statistical analysis was made with SPSS 21.0 for IBM. Kruskal Wallis test, Mann Whitney U test and Correspondence Analysis were used in order to evaluate the level of significance (p |
