Effect Of Bioactive Irrigants On Intraradicular Dentin Microstructure During Endodontic Therapy

Irrigation using sodium hypochlorite is the most recommended irrigating solution in endodontics for the removal of remnants and dentine debris during instrumentation, however, it may cause changes to the organic and mechanical properties of dentine. Previous studies have shown that modification to the collagen by altering the number of cross-links, enhance the mechanical properties and lower rates of enzymatic degradation. Plant derived natural products represent a rich source of antimicrobial compounds. Grape seed extract (GSE), mainly composed of Proanthocyanidin and Tannic acid which is a chemical derived from certain plants, such as oak wood, have demonstrated the ability to create inter- and intra-molecular collagen cross-links in biological tissue. These cross-links affect the mechanical properties of demineralized dentin by increasing the level of stiffness, as measured by the Flexural Strength, and provide resistance against enzymatic degradation. We hypothesize that the use of crosslinking agents tannic acid (TA) and grape seed extract (GSE) will not have a significant effect on the flexural strength and dentin collagen biodegradation of intraradicular dentin. Extracted single-rooted permanent teeth were sectioned into 7x3x0.3 mm3 beams and randomly assigned to four groups according to the irrigation type : Group 1: Saline, Group 2: EDTA 17%, 5.25%NaOCl; Group 3:5.25% NaOCl, 20% TA , Group 4: 5.25% NaOCl, 30% GSE. Specimens were tested for flexural strength (MPa), dentin collagen biodegradation using bacterial collagenase for 24 hours, and calculating the amount of digested matrix, and denaturation temperature of dentin matrix. Statistical analysis was performed using one-way ANOVA test (α=0.05). To assess flexural strength, specimens were loaded to fracture at a crosshead speed of 1mm/min. Data analysis was performed by one-way ANOVA test (α= 0.05), and revealed no statistically significant differences in flexural strength among groups , although high values were observed for TA in comparison to EDTA>NaOCl , GSE, and Saline groups. TA was borderline significance in reducing the collagen degradability when compared to the other irrigants. Therefore, we concluded that the use of saline, NaOCl, TA and GSE didn’t affected the flexural strength, rate of collagen biodegradation and collagen thermal transition of root dentin, and the null hypothesis was accepted.