The effect of hydrofluoric acid concentration on the fatigue failure load of adhesively cemented feldspathic ceramic discs

• Published in: Dental materials 2018-04, Vol.34 (4), p.667-675
• Main Authors: Venturini, Andressa B., Prochnow, Catina, Pereira, Gabriel K.R., Werner, Arie, Kleverlaan, Cornelis J., Valandro, Luiz Felipe
• Format: Article
• Language: English
• Subjects: Acid etching; Acid Etching, Dental; Adhesive bonding; Aluminum Silicates - chemistry; Cementation; Cementing; Ceramics; Ceramics - chemistry; Control methods; Crack propagation; Cyclic loads; Data processing; Dental Cements - chemistry; Dental equipment; Dental Restoration Failure; Dental Stress Analysis; Dentistry; Etching; Failure analysis; Failure load; Fatigue; Fatigue cracks; Fatigue failure; Glass ceramics; Hydrofluoric acid; Hydrofluoric Acid - chemistry; In Vitro Techniques; Materials fatigue; Materials Testing; Mechanical cycling; Potassium Compounds - chemistry; Primers (coatings); Resin Cements - chemistry; Surface Properties; Surface treatment; Variance analysis
• ISSN: 0109-5641; 1879-0097
• DOI: 10.1016/j.dental.2018.01.010

•Hydrofluoric acid (HF) concentration on the fatigue failure load was investigated.•5% and 1% HF etching for 60s have demonstrated a deleterious effect.•10% HF had no negative influence and seems the recommended protocol for etching. This study investigated the influence of hydrofluoric acid (HF) etching at different concentrations on the fatigue failure load of adhesively cemented feldspathic ceramic discs (Vita Mark II). Besides, their effect on the micromorphology of ceramic surface was investigated. Eighty ceramic discs (ϕ=10 mm; thickness=1.5 mm) were cemented to epoxy supporting discs (ϕ=10 mm; thickness=2.0mm) using different surface conditioning methods (n=20): nonetched control (CTRL), or etched for 60s with different HF concentrations: 1% (HF1), 5% (HF5), or 10% (HF10). All the ceramic discs received a silane application (Monobond Plus). The epoxy discs were etched with 10% HF for 60s and received a primer coating (Multilink Primer A+B). Adhesively cementation was performed (Multilink Automix), and the assemblies (ceramic discs/epoxy discs) were subjected to cyclic loads in water by a staircase approach (500,000 cycles; 20Hz; initial load=290N; step size=30N). Fatigue failure load data were analyzed using 1-way ANOVA and post-hoc Tukey’s tests (α=.05). Mean failure load of the HF5 group (255.0±23.0N) was significantly lower; HF1 group (301.7±71.0N) presented intermediate values, and the highest values were achieved in CTRL (351.7±13.4N) and HF10 (341.7±20.6N) groups. All the failures were radial cracks starting from the bonding surface. In terms of fatigue failure load, etching with 1% and 5% HF had a deleterious effect on the fatigue behavior of an adhesively cemented feldspathic ceramic, while 10% HF had no negative influence.