Rhus coriaria L. Binding Capacity to Mineralized versus Demineralized Dentin

Objectives: Rhus coriaria L. has been shown to inhibit host-derived collagen degradation in demineralized dentin matrices. The aim of the study was to evaluate the binding capacity of Rhus coriaria L. extract (RCE) to mineralized versus demineralized dentin powder as a function of concentration, and to determine how much debinding would result from rinsing with water, 4N GuanidinHCl, 4N Urea or 0.5M NaCl in water.

Methods: Dentin powder was prepared from coronal dentin of extracted human third molars and was mixed with different concentrations of 1 mL RCE (w/v 5%-20%) for 30 min at 37°C. After centrifuging the tubes, the supernatant was removed and diluted for 40-fold in water. The quantification of RCE concentration was measured by UV-spectroscopy at 225 nm. RCE-treated dentin powder was resuspended in water, 0.5 M NaCl, 4N GuanidinHCl or 4N Urea to determine if these solvents could debind RCE. After centrifugation, the supernatant was retested for the quantification of debound RCE in the solvents by UV-spectroscopy. Data were analyzed by using Kruskal–Wallis test using Dunn’s multiple comparison test at α=0.05.
Results: Demineralized dentin bound up to 50% more RCE compared to mineralized dentin with the exception of 20% RCE which showed ≈120% higher RCE binding for demineralized dentin. The GSE binding to demineralized and mineralized dentin powder increased significantly by the high concentration up to 603.2.2 µg/mg dentin and 280.8 µg/mg dentin respectively (p<0.05). Debinding of RCE was in the order: NaCl≤waterConclusions: The results suggest that at high concentrations RCE binds anionic dentin by hydrogen bonding and resists the action of rinsing by solvents. RCE may remain bound to demineralized dentin during resin-dentin bonding.