Effect of Tannic Acid on Resistance to Vertical Root Fracture in Endodontically Treated Bovine Teeth

Sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are the most common irrigating solutions used during endodontic treatment. However, both solutions have the potential to cause negative effects on the mechanical properties of dentin. Tannic acid (TA) has demonstrated the ability to induce collagen cross-linking in cardiac muscles tissues. In addition, tannic acid has shown positive effects on the mechanical properties of dentin in previous studies. The null hypothesis tested that the addition of tannic acid to the irrigation protocol and/or endodontic sealer will not have a significant effect on the resistance to vertical root fracture (VRF) in endodontically treated bovine teeth. Thirty bovine primary anterior teeth were decoronated at the cemento-enamel junction to create 15mm long roots and were then randomly assigned into three groups according to the irrigation and sealer type: Group 1: 5.25% NaOCl, 17% EDTA, 5.25% NaOCl; then gutta-percha and Roth sealer; Group 2: 5.25% NaOCl, 17% EDTA, 20% TA; then gutta-percha and Roth sealer; Group 3: 5.25% NaOCl, 17% EDTA, 20% TA then gutta-percha and Roth sealer with 10% TA. The specimens received endodontic treatment and were tested for vertical loading force (Newtons) until fracture using the MTS testing system. Data analysis was performed using one-way (ANOVA) and Tukey’s (HSD) as a post-hoc test, (α<0.05). A statistical significant difference was detected between group 1 (control) and group 2 (20% TA irrigation) as well as group 1 (control) and group 3 (20% TA irrigation and sealer with 10% TA). In conclusion, the addition of tannic acid to the irrigation protocol, as well as to endodontic sealer, had a significant effect on the resistance to VRF, thus the null hypothesis was rejected.