Interaction between 2-ethoxybenzoic acid (EBA) and eugenol, and related changes in cytotoxicity

Area of Science:

• Biomaterials Science
• Dental Materials
• Toxicology

Background:

• Eugenol, a component in some dental cements, can generate harmful radicals at higher pH.
• These eugenol radicals may directly damage cells, raising concerns about cement safety.

Purpose of the Study:

• To investigate eugenol radical generation from eugenol/calcium hydroxide mixtures.
• To determine if 2-ethoxybenzoic acid or acetylsalicylic acid can scavenge these radicals.
• To assess the cytotoxic effects of eugenol in combination with other cement components on human cells.

Main Methods:

• Electron spin resonance spectroscopy was used to detect and quantify radicals.
• Cytotoxicity assays were performed on human pulp fibroblasts and a human submandibular gland cancer cell line.
• Radical generation and scavenging were studied in a 50% dimethylsulfoxide solution with varying pH and buffering agents.

Main Results:

• Eugenol radicals were successfully generated from the eugenol/calcium hydroxide mixture.
• 2-ethoxybenzoic acid dose-dependently reduced eugenol radical intensity, while acetylsalicylic acid enhanced it.
• Eugenol's cytotoxicity was reduced by 2-ethoxybenzoic acid but increased by acetylsalicylic acid; calcium hydroxide's cytotoxicity was unaffected.

Conclusions:

• 2-ethoxybenzoic acid appears to suppress the generation of eugenol radicals in 2-ethoxybenzoic acid cements.
• The interaction between eugenol, 2-ethoxybenzoic acid, and acetylsalicylic acid influences radical formation and cytotoxicity.
• These findings suggest a potential mechanism for improving the biocompatibility of eugenol-containing dental materials.