fa Effects of Surface Treatments, Thermocycling, and Cyclic Loading on the Bond Strength of a Resin Cement Bonded to a Lithium Disilicate Glass Ceramic ترمیمی Cosmetic and Restorative Dentistry پژوهشي Research <p> <strong>Clinical Relevance</strong></p><p>  The current results indicate that acid etching is a better option than air abrasion when bonding IPS e.max Press ceramic to dual-cure RelyX ARC resin cement. However, both fatigue and thermocycling decrease the bond strength. </p><p> <strong>SUMMARY</strong></p><p> <strong> Objectives</strong>: </p><p> The aim of this present study was to investigate the effect of two surface treatments, fatigue and thermocycling, on the microtensile bond strength of a newly introduced lithium disilicate glass ceramic (IPS e.max Press, Ivoclar Vivadent) and a dual-cured resin cement.</p><p> <strong> Methods</strong>:</p><p>  A total of 18 ceramic blocks (10 mm long × 7 mm wide × 3.0 mm thick) were fabricated and divided into six groups (n=3): groups 1, 2, and 3—air particle abraded for five seconds with 50-μm aluminum oxide particles groups 4, 5, and 6—acid etched with 10% hydrofluoric acid for 20 seconds. A silane coupling agent was applied onto all specimens and allowed to dry for five seconds, and the ceramic blocks were bonded to a block of composite Tetric N-Ceram (Ivoclar Vivadent) with RelyX ARC (3M ESPE) resin cement and placed under a 500-g static load for two minutes. The cement excess was removed with a disposable microbrush, and four periods of light activation for 40 seconds each were performed at right angles using an LED curing unit (UltraLume LED 5, Ultradent) with a final 40 second light exposure from the top surface. All of the specimens were stored in distilled water at 37°C for 24 hours. Groups 2 and 5 were submitted to 3,000 thermal cycles between 5°C and 55°C, and groups 3 and 6 were submitted to a fatigue test of 100,000 cycles at 2 Hz. Specimens were sectioned perpendicular to the bonding area to obtain beams with a cross-sectional area of 1 mm2 (30 beams per group) and submitted to a microtensile bond strength test in a testing machine (EZ Test) at a crosshead speed of 0.5 mm/min. Data were submitted to analysis of variance and Tukey post hoc test (p≤0.05). </p><p> <strong>Results:</strong></p><p>  The microtensile bond strength values (MPa) were 26.9 ± 6.9, 22.2 ± 7.8, and 21.2 ± 9.1 for groups 1–3 and 35.0 ± 9.6, 24.3 ± 8.9, and 23.9 ± 6.3 for groups 4–6. For the control group, fatigue testing and thermocycling produced a predominance of adhesive failures. Fatigue and thermocycling significantly decreased the microtensile bond strength for both ceramic surface treatments when compared with the control groups. Etching with 10% hydrofluoric acid significantly increased the microtensile bond strength for the control group. </p><hr><p></p><p> <strong>Source: </strong>Operative Dentistry </p><p><a href="http://www.jopdentonline.org/doi/abs/10.2341/11-076-L" target="_blank"><font color="#0000ff"> Full Text</font></a></p> 0 0 http://idai.ir/browse.php?a_code=A-10-32-2681&slc_lang=fa&sid=1 Guilherme Bottene Guarda 100319475328460012604 100319475328460012604 No Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, State University of Campinas – UNICAMP, Piracicaba, SP, Brazil Américo Bortolazzo Correr 100319475328460012605 100319475328460012605 No Luciano Sousa Gonçalves 100319475328460012606 100319475328460012606 No Ana Rosa Costa 100319475328460012607 100319475328460012607 No Gilberto Antonio Borges 100319475328460012608 100319475328460012608 No Mário Alexandre C Sinhoreti 100319475328460012609 100319475328460012609 No Lourenço Correr-Sobrinho sobrinho@fop.unicamp.br 100319475328460012610 100319475328460012610 Yes