Evaluation of roughness promoted by different concentrations and exposure times to hydrofluoric acid on ceramic surfaces reinforced by lithium dissilicate

Ana Paula de Almeida Nunes, Ana Paula Silva de Mello, Karla Lorene de França Leite, Elson Braga de Mello, Diogo de Azevedo Miranda

ABSTRACT: Introduction: Lithium disilicate-based ceramics have optical properties that make them stand out, and adhesion to the remaining dental structure is obtained from the sensitivity of this group of material to the action of hydrofluoric acid (AF), which allows the exposure of crystals of lithium disilicate and favors bonding to resin cementing agents. For the AF to be used without prejudice to the structural rigidity of the ceramic or to the quality of adhesion, care with its concentration and exposure time are essential. Objective: The study evaluated the influence of hydrofluoric acid in different concentrations and application times on the surface roughness of ceramic based on lithium disilicate. Methods: 32 circumferential specimens were made, divided into four groups according to the hydrofluoric acid application protocol, varying the concentration and conditioning time, namely: G1 - 5%, 40s; G2 - 5%, 80s; G3 - 10%, 20s; G4 - 10%, 40s. Surface roughness averages were obtained by three-dimensional profileometric analysis and evaluation of microphotographs by scanning electron microscopy, analyzed statistically, and with generation of images for qualitative analysis. Results: In groups 1, 2 and 4 there was a significant increase in surface roughness after the action of hydrofluoric acid. Three-dimensional images allowed us to infer that the specimens of group 1 showed a greater variation in peaks and valleys. Conclusion: It was concluded that the hydrofluoric acid promoted changes in the ceramic surface, being recommended its use for 40 seconds, in a concentration of 5%.

Keywords: Hydrofluoric Acid; Dental Porcelain; Scanning Electron Microscopy.

How to cite: Nunes APA, Mello APS, Leite KLF, Mello EB, Miranda DA. Evaluation of roughness promoted by different concentrations and exposure times to hydrofluoric acid on ceramic surfaces reinforced by lithium dissilicate. J Clin Dent Res. 2020 Jan-Apr;17(1):128-41.

Saturday, November 23, 2024 02:04