title: Effect of etching with distinct hydrofluoric acid concentrations on the flexural strength of a lithium disilicate-based glass ceramic.
abstract: This study examined the effects of distinct hydrofluoric acid concentrations on the mechanical behavior of a lithium disilicate-based glass ceramic. Bar-shaped specimens were produced from ceramic blocks (e.max CAD, Ivoclar Vivadent). The specimens were polished, chamfered, and sonically cleaned in distilled water. The specimens were randomly divided into five groups (n = 23). The HF1, HF3, HF5, and HF10 specimens were etched for 20 s with acid concentrations of 1%, 3%, 5%, and 10%, respectively, while the SC (control) sample was untreated. The etched surfaces were evaluated using a scanning electron microscope and an atomic force microscope. Finally, the roughness was measured, and 3-point bending flexural tests were performed. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey's test (α = 0.05). The Weibull modulus and characteristic strength were also determined. No statistical difference in the roughness and flexural strength was determined among the groups. The structural reliabilities (Weilbull moduli) were similar for the tested groups; however, the characteristic strength of the HF1 specimen was greater than that of the HF10 specimen. Compared with the untreated ceramic, the surface roughness and flexural strength of the ceramic were unaffected upon etching, regardless of the acid concentration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 885-891, 2017.
authors: PhD Graduate Program in Oral Sciences (Prosthodontics Unit), School of Dentistry, Federal University of Santa Maria, Rio Grande do Sul State, Santa Maria, Brazil.
authors: Catina
authors: C
authors: Prochnow
authors: PhD Graduate Program in Oral Sciences (Prosthodontics Unit), School of Dentistry, Federal University of Santa Maria, Rio Grande do Sul State, Santa Maria, Brazil.
authors: Andressa B
authors: AB
authors: Venturini
authors: PhD Graduate Program in Oral Sciences (Prosthodontics Unit), School of Dentistry, Federal University of Santa Maria, Rio Grande do Sul State, Santa Maria, Brazil.
authors: Rafaella
authors: R
authors: Grasel
authors: Department of Restorative Dentistry (Division of Dental Biomaterials), Indiana University School of Dentistry, Indianapolis, Indiana.
authors: Marco C
authors: MC
authors: Bottino
authors: PhD Graduate Program in Oral Sciences (Prosthodontics Unit), School of Dentistry, Federal University of Santa Maria, Rio Grande do Sul State, Santa Maria, Brazil.
authors: Luiz Felipe
authors: LF
authors: Valandro
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D006858:Hydrofluoric Acid / Q000737:chemistry*; D013314:Stress, Mechanical
chemical_list: C493120:lithia disilicate; D003776:Dental Porcelain; D006858:Hydrofluoric Acid
keywords: acid etching; atomic force microscopy; flexural strength; glass ceramic; surface conditioning