Hydrofluoric acid concentration and etching time affect differently the microstructure and surface properties of pressed lithium disilicate glass ceramics

• Published in: Journal of esthetic and restorative dentistry Vol. 36; no. 1; pp. 47 - 55
• Main Authors: Alves, Larissa M. M., Campos, Tiago M. B., Bergamo, Edmara T. P., Benalcazar Jalkh, Ernesto B., Gierthmuehlen, Petra C., Sailer, Irena, Thim, Gilmar P., Strazzi‐Sahyon, Henrico B., Celestrino, Marcos, Guimarães, Carolina C. L., Bonfante, Estevam A.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.01.2024; Blackwell Publishing Ltd
• Subjects: acid etching; Acids; Ceramics - chemistry; Chemical composition; Crystals; Dental Bonding - methods; Dental Porcelain - chemistry; Etching; glass composition; hydrofluoric acid; Hydrofluoric Acid - chemistry; Lithium; lithium disilicate glass ceramic; Materials Testing; microstructure; Optical properties; Resin Cements - chemistry; Scanning electron microscopy; Spectroscopy; Surface Properties; glass composition; hydrofluoric acid; lithium disilicate glass ceramic; microstructure; acid etching
• ISSN: 1496-4155; 1708-8240; 1708-8240
• DOI: 10.1111/jerd.13140

Objective To evaluate the effect of different hydrofluoric acid concentrations and etching times on the surface, chemical composition and microstructure of lithium disilicate. Material and Methods Ninety specimens of pressed lithium disilicate (LDS) were obtained (IPS e.max Press, Rosetta SP and LiSi Press). The specimens of each material were divided in two groups according to the hydrofluoric acid concentration: 5% and 10% (n = 15/group), and subdivided according to the etching time: 20, 40 and 60 s (n = 5/group). Crystalline evaluations and chemical composition were performed through x‐ray diffraction (XRD) and energy‐dispersive x‐ray spectroscopy (EDS), respectively. Microstructural analyses were performed by scanning electron microscope (SEM), surface roughness (Ra), and material thickness removal evaluation. Thickness removal and Ra data were analyzed by ANOVA and Tukey test (p < 0.05). Results XRD demonstrated characteristic peaks of lithium disilicate crystals, lithium phosphate and of a vitreous phase for all materials. EDS identified different compositions and SEM confirmed different surface responses to acid etching protocols. Material and etching time influenced Ra and material thickness removal (p < 0.05). Conclusion Hydrofluoric acid concentration and etching time affect the surface characteristics of LDS differently. LiSi Press presented higher resistance to hydrofluoric acid etching compared to e.max Press and Rosetta SP. Clinical Significance Applying the appropriate etching protocol is pivotal to avoid excessive material removal and to prevent jeopardize the mechanical and optical properties of the material.