Effect of Solvents on Dentin Collagen Cross-linking Potential of Carbodiimide

Purpose: This study compared the dentin collagen cross-linking potential of carbodiimide (EDC) prepared in three most commonly used solvents in dental adhesive systems: water, ethanol, and acetone. Materials and Methods: Thirty-eight extracted caries-free human permanent molars were used in this study. Demineralized dentin beams were prepared and cross linked by 0.3 M EDC in water, acetone, or ethanol. The modulus of elasticity of demineralized dentin, the resistance of dentin matrix to enzymatic degradation, the swelling ratio, and the mass change of demineralized dentin matrix were examined to compare the cross-linking efficacy of EDC in their respective solvents. Results: The modulus of elasticity of demineralized dentin cross linked by EDC in acetone was significantly higher (p 0.05) than demineralized dentin cross linked by EDC in ethanol and EDC in water. Furthermore, the ultimate tensile strength of demineralized dentin cross linked by EDC in water and ethanol dropped significantly following enzymatic degradation, while the ultimate tensile strength of demineralized dentin cross linked by EDC in acetone was preserved. The swelling ratio of demineralized dentin cross linked by EDC in acetone and ethanol was significantly lower (p 0.05) than that of demineralized dentin cross linked by EDC in water. Conversely, the mass change of demineralized dentin cross linked by EDC in acetone was significantly higher (p 0.05) than demineralized dentin cross linked by EDC in water and EDC in ethanol. Conclusion: The dentin collagen cross-linking potential of EDC could be enhanced by using acetone as a solvent. Keywords: carbodiimide, cross linking, collagen, dentin, solvents