Hydrofluoric acid concentrations: Effect on the cyclic load-to-failure of machined lithium disilicate restorations.

摘要: Abstract Objectives To evaluate the effects of etching with different hydrofluoric acid (HF) concentrations on cyclic load-to-failure ( C L f ) machined lithium disilicate crowns cemented to dentin analogue material. Methods Pairs prosthetic preparations and ceramic simplified standardized designs were (n = 18). The etched 10% HF (60 s), followed by primer application. intaglio surface was treated as follows: non-etched (control, CTRL); or for 20 s — 3% (HF3), 5% (HF5), (HF10). A silane coating then applied onto surfaces, they adhesively preparations. perform fatigue tests (staircase approach), a hemispheric stainless-steel piston (O = 40 mm) loads in center under water (initial load: 720 N; step-size: 70 N; cycles: 500,000; frequency: 20 Hz). Additionally, topographic, fractographic, fractal analyses carried out. data analyzed using Dixon Mood method. Results Although topographic depicted action altering superficial complexity topography, preponderant topography pattern established machining CAD/CAM. All groups showed similar CLf (in N) (CTRL = 805.00 ± 91.23; HF3 = 781.25 ± 29.87; HF5 = 755.00 ± 154.49; HF10 = 833.75 ± 100.74). Significance Etching did not promote deleterious effect crowns.