Natural Extracts as Biological Smear Layer Removing Agents: A Literature Review

OBJECTIVES: The aim of this article is to identify whether natural irrigants are better than synthetic conventional irrigants for smear layer removal and to analyze their influence on mechanical and chemical radicular dentin properties. MATERIALS AND METHODS: The last electronic search was performed on June 2020 through five databases, limited to articles either published or accepted for publication in the English language using the following keywords: “Natural extracts” or “Fruit and plant extracts” and “Smear layer removal.” RESULTS: According to the inclusion criteria, 36 articles were included. Most studies revealed that apple or apple cider vinegars, grape seed extract, citrus aurantifolia, 5–10% glycolic acid, and 0.5–1% phytic acid effectively removed the smear layer better or similar to synthetic conventional agents. CONCLUSION: Natural irrigants are effective smear layer removing agents with the least deteriorated effect on mechanical and chemical radicular dentin properties compared with synthetic agents.