Comparison of methanol/hydrochloric, ferric chloride acid versus tribochemical silica coating for adhesion of resin cement to zirconium dioxide
Year: 2016
Journal: J. Adhes. Sci. Technol.
Authors: de Carvalho, RF; Ozcan, M; Louzada, F; Monteiro, E; Bottino, MA; de Melo, RM; Valandro, LF
This study compared air-abrasion and etching regimens on adhesion of resin luting agent to zirconium dioxide. Ceramic specimens (LAVA, 3 M ESPE) (N = 16) were embedded in acrylic resin and exposed surfaces were polished. The specimens were randomly assigned into four groups (n = 12, 3 specimens for each disc): SC: Air-borne particle abrasion (30 mu m aluminum oxide particles coated with silica, CoJet, 3 M ESPE); MH: Heated chemical solution (Methanol-800 mL; 37% Hydrochloric Acid-200 mL; Ferric Chloride-2 g) at 100 degrees C for 30 min, MHP: Primer (Metal/Zirconia Primer, Ivoclar Vivadent) + MH, P: Primer only (Metal/Zirconia Primer). Cylindrical molds (internal diameter: 0.7 mm; height: 1.5 mm) were placed on each conditioned specimen, filled with resin cement (Multilink Automix) and photo-polymerized for 60 s. After 24 h, the molds were removed and the specimens were stored in distilled water at 37 degrees C for six months). Microshear test was performed in a Universal Testing Machine (1 mm/min). Failures types were classified as adhesive, mixed, or cohesive. In another set of specimens (n = 2 per group) contact angle measurements were recorded. Data were analyzed statistically using Kruskal-Wallis and Dunn's tests (alpha = 0.05). The surface conditioning method significantly affected the mean bond strength (MPa) (p < 0.0001): SC(18.3 +/- 0.3)(a) < P(5.00 +/- 0.07)(b) < MHP(4.7 +/- 0.08)(c) < MH(0.84 +/- 0.01)(c). While Group SC showed mainly adhesive (58%) and mixed (41.7%) failure types, groups MH, MHP, and P presented exclusively adhesive failures. SC, MHP, and P (29-32 degrees) showed lower contact angle than MH (78.9 degrees). Volume loss was the highest with MHP (9.92 mu l) followed by SC (9.67 mu l).
