Review of Dye Methods for Microleakage Assessment in Restorative Dentistry and Endodontics

OBJECTIVE: To compare and critically evaluate dye-based methods used for microleakage assessment, particularly focusing on dye penetration and dye extraction techniques, their advantages and drawbacks. MATERIALS AND METHODS: An electronic search of PubMed and Scopus databases was conducted to identify relevant articles from 2020 to 2025. After eligibility assessment, a total of 45 articles were included in this review, followed by data extraction and qualitative analysis. RESULTS: Both dye penetration and dye extraction methods face significant challenges, including lack of standardization, methodological variability, and limited correlation with clinical outcomes. The identified confounding factors, such as anatomical variations, dye properties, sectioning errors, and measurement inconsistencies, heavily influence the reliability of results. While dye penetration enables localization of leakage pathways, it is limited by two-dimensional analysis and random cutting axis. Dye extraction, although more objective, is destructive and lacks spatial information. Recommendations for protocol standardization and methodology improvement include the use of anatomically matched samples or 3D-printed replicas, thermomechanical aging, fluorescent dyes and advanced imaging techniques for nondestructive three-dimensional analysis, such as confocal laser scanning microscopy (CLSM) and micro-computed tomography (micro-CT). CONCLUSION: Although in vitro microleakage testing continues to face validity concerns, well-designed studies with rigorous controls still provide valuable insights. Future research should focus on combining in vitro techniques with in vivo and long-term clinical studies to improve the translation of findings into clinical practice.