Martins, Ayala, D'Alpino, Calixto, Gomes, Gomes stein), and a one-step self-etching system [APL- Finally, after marginal evaluation, the speci- P] (Adper Prompt L-Pop, 3M/ESPE, St. Paul, MN, mens were embedded in epoxy resin (Castin’ Craft USA). Half of the sample (n=10) was submitted to Clear Liquid Plastic, Environmental Technology thermo-mechanical cycles in distilled water for 500 Inc., Fields Landing, CA, USA), allowing each tooth cycles between 5 and 55° C, with a dwell time of to be mounted and sectioned using a water cooled 15 s (El Quip, MSCT-3, USA). Two coats of nail var- rotating diamond blade (Isomet Low Speed Saw, nish were then applied, leaving a 1 mm-wide bor- Buehler Ltd., Evanston, IL, USA). Each restoration der around the margins of the restoration. Then the was sectioned resulting in two slices. Both sec- teeth were submitted to 50,000 mechanical cycles tioned surfaces were examined, but results of the (El Quip, MSFM, USA). In this case, a perpendicular two sections were taken as single data. After sec- loading of 40-70 N was applied at the occlusal sur- tioning, each specimen was wet-polished with 600-, face. The other half of the sample received no ther- 1200-, and 2000-grit SiC papers. Then, the speci- mo-mechanical treatment. Control and thermo- mens were acid-etched (37% phosphoric acid gel) mechanically cycled groups were then immersed in in order to remove the debris. The specimen prepa- a 50 % AgNO3 solution for 2 h in a dark room. After ration for SEM included a high vacuum silica-gel washing, the specimens were placed in a devel- desiccation process for 48 h.18 Then, the specimens oper solution and exposed to fluorescent light for were sputter-coated (Sputter Coater, model SCD 6 h17 (HC-110 Developer, Eastman Kodak Company, 050, Balzers) with a thin palladium-gold film for 100 Rochester, NY, USA). The specimens were then sec- s at 40 mA (approximately 25 nm in thickness). The tioned and the microleakage at the dentin/cemen- axial gaps were imaged using a magnification of tum margin was analyzed using an optical micro- 1000X. The gap width was measured in three differ- scope (Olympus BX41/Camera DP71, Japan) at 40 ent areas in each photomicrograph image and the X magnification. The microleakage was rated using mean value of each area was calculated. the following four classifications: • Score 0 – absence of penetration of tracer Microtensile bond strength test agent; For the microtensile bond strength test, 18 • Score 1 – penetration to one-third of the cavity; sound human third molars were selected. The • Score 2 – penetration to two-thirds of the cav- cusps were abraded using a water-cooled rotating ity, and diamond wheel (Isomet 1000, Buehler; Lake Bluff, • Score 3 – penetration to more than two-thirds IL, USA) to expose a flat surface free of enamel tis- and in the axial wall of the cavity. sue in the mid-coronal dentin surface. A standard- Table 1. Composition and application mode of the materials used. Product name Ingredients Batch # 4BC J09568 293053 Adper Single Bond 2 (3M ESPE) AdheSE Vivadent) (Ivoclar Adper Prompt-L-Pop (3M ESPE) Bis-GMA: Bisfenol-A diglicidil dimethacrylate; HEMA: 2-Hydroxyethyl methacrylate April 2012 - Vol.6 171 European Journal of Dentistry Application Etching: Apply Scotchbond™ Etchant to enamel and dentin for 15 s. Water-rinse for 10 s. Blot excess water using a cot- ton pellet or mini-sponge. Adhesive: Immediately after blotting, apply 2-3 consecutive coats of adhesive to etched enamel and dentin for 15 s with gentle agitation using a fully saturated applicator. Gently air thin for five seconds to evaporate solvents. Light cure for 10 s. Etch-and-rinse, conventional adhesive sys- tem; Bis-GMA; polyalkenoic acid co-poly- mer; dimethacrylates; HEMA; photoinitia- tors; ethanol; water; nanofiller particles. acrPyrlaimmeidr:e;pwhoasteprh;oinniictiaatcoidrsaacnrydlasttea;bBiliizse-rs. totAaplprleyaacntioandetiqmueatsehaomulodunnottobfeprsihmoertrearstshuarnin3g0tsh.aEtxthceess Bond: dimethacrylates; hydroxyethyl meth- primer dispersed with a strong stream of air until the acrylate; highly dispersed silicon dioxide. mobile liquid film is no longer visible. Application of bond, Initiators and stabilizers; Activator; Solvent; beginning with the dentin tissue. Bond dispersed with a very Initiators. weak stream of air. Bond photoactivated for 10 s. Liquid 1 (red blister): methacrylated phos- After mixing the content of the reservoirs, apply adhesive to phoric esters; Bis-GMA; Initiator: cam- the entire surface of the cavity, rubbing in the solution with phorquinone; stabilizers moderate finger pressure for 15 s. Use a gentle stream of Liquid 2 (yellow blister): water; HEMA; air to thoroughly dry the adhesive to a thin film. Light cure Polyalkenoic acid; stabilizers for 10 s.