Effect of Hydrofluoric Acid Concentration on Bond Strength to Glass-Ceramics: A Systematic Review and Meta-Analysis of In-Vitro Studies

Purpose: To conduct a systematic review and meta-analysis of in-vitro bond strength to glass-ceramics using hydrofluoric acid (HF) at lower (<5%) and higher (>5%) concentrations ([HF]) to treat ceramic surfaces.Methods: Systematic searches were carried out in PubMed, Scopus, LILACS, and Web of Science for articles published through July 2021, and a meta-analysis was performed to estimate the combined effect by comparing the differences between the standardized means of the bond strengths of the evaluated materials.Results: In total, 943 articles were found, of which 17 studies were selected for qualitative analysis and 12 for quantitative analysis. The bond strength to glass-ceramics using 4% to 5% HF did not differ from that using 7% to 10% HF for the following HF etching times and glass-ceramic materials: 20 s for lithium-disilicate (Z=0.65, p=0.51), 60 s for feldspathic (Z=0.53, p=0.60), and 60 s for leucite (Z=0.72, p=0.35).Conclusion: The lower concentration HF (<5%) etchant is a reliable surface treatment for adhesive bonding to glass-ceramics with satisfactory bond strength in short-term evaluations.