Impact of Hydrofluoric Acid Etching Duration on Translucency, Flexural Strength and Surface Topography of Lithium Silicate Based Glass Ceramic

The aim of this study was to examine the effect of different acid etching times on the surface roughness and flexural strength of a lithium disilicate-based glass ceramic. Ceramic bar-shaped specimens (16 mm x 2 mm x 2 mm) were produced from ceramic blocks. All specimens were polished and sonically cleaned in distilled water. Specimens were randomly divided into 5 groups (n=15). Group A (control) no treatment. Groups B-E were etched with 4.9% hydrofluoric acid (HF) for 4 different etching periods: 20 s, 60 s, 90 s and 180 s, respectively. Etched surfaces were observed under scanning electron microscopy. Surface profilometry was used to examine the roughness of the etched ceramic surfaces, and the specimens were loaded to failure using a 3-point bending test to determine the flexural strength. Data were analyzed using one-way ANOVA and Tukey's test (?=0.05). All etching periods produced significantly rougher surfaces than the control group (p<0.05). Roughness values increased with the increase of the etching time. The mean flexural strength values were (MPa): A=417 ± 55; B=367 ± 68; C=363 ± 84; D=329 ± 70; and E=314 ± 62. HF etching significantly reduced the mean flexural strength as the etching time increased (p=0.003). In conclusion, the findings of this study showed that the increase of HF etching time affected the surface roughness and the flexural strength of a lithium disilicate-based glass ceramic, confirming the study hypothesis.

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Hard machining, glaze firing and hydrofluoric acid etching: Do these procedures affect the flexural strength of a leucite glass–ceramic?

Dental Materials ◽

10.1016/j.dental.2015.04.005 ◽

2015 ◽

Vol 31 (7) ◽

pp. e131-e140 ◽

Cited By ~ 24

Author(s):

Sara Fraga ◽

Luiz F. Valandro ◽

Marco A. Bottino ◽

Liliana G. May

Keyword(s):

Flexural Strength ◽

Glass Ceramic ◽

Hydrofluoric Acid ◽

Acid Etching ◽

Hard Machining

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Acid Etching as Surface Treatment Method for Luting of Glass-Ceramic Restorations, part 1: Acids, Application Protocol and Etching Effectiveness

Open Access Macedonian Journal of Medical Sciences ◽

10.3889/oamjms.2018.147 ◽

2018 ◽

Vol 6 (3) ◽

pp. 568-573 ◽

Cited By ~ 4

Author(s):

Emilija Barjaktarova-Valjakova ◽

Anita Grozdanov ◽

Ljuben Guguvcevski ◽

Vesna Korunoska-Stevkovska ◽

Biljana Kapusevska ◽

...

Keyword(s):

Surface Treatment ◽

Glass Ceramic ◽

Hydrofluoric Acid ◽

Treatment Method ◽

Acid Etching ◽

Etching Time ◽

Ceramic Surface ◽

Adhesive Luting ◽

Ceramic Restorations ◽

Etching Effect

AIM: The purpose of this review is to represent acids that can be used as surface etchant before adhesive luting of ceramic restorations, placement of orthodontic brackets or repair of chipped porcelain restorations. Chemical reactions, application protocol, and etching effect are presented as well.STUDY SELECTION: Available scientific articles published in PubMed and Scopus literature databases, scientific reports and manufacturers' instructions and product information from internet websites, written in English, using following search terms: “acid etching, ceramic surface treatment, hydrofluoric acid, acidulated phosphate fluoride, ammonium hydrogen bifluoride”, have been reviewed.RESULTS: There are several acids with fluoride ion in their composition that can be used as ceramic surface etchants. The etching effect depends on the acid type and its concentration, etching time, as well as ceramic type. The most effective etching pattern is achieved when using hydrofluoric acid; the numerous micropores and channels of different sizes, honeycomb-like appearance, extruded crystals or scattered irregular ceramic particles, depending on the ceramic type, have been detected on the etched surfaces.CONCLUSION: Acid etching of the bonding surface of glass - ceramic restorations is considered as the most effective treatment method that provides a reliable bond with composite cement. Selective removing of the glassy matrix of silicate ceramics results in a micromorphological three-dimensional porous surface that allows micromechanical interlocking of the luting composite.

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