Biocompatibility Evaluation of Three Different Root-end Filling Materials

Objective: To establish periapical periodontitis model and test the biocompatibility of three different root-end filling materials.

Materials and Methods: A total of 36 roots of mandibular premolars from three 1.5-yr-old beagle dogs were used. After gaining occlusal access to the pulp chambers of each tooth, the pulps were extirpated, each root canals were cleaned to the apical stop to ISO size file #20. They were randomly divided into 3 groups with 12 roots of each group. The chambers of each tooth was opened to the oral environment for 1, 2, 3 weeks respectively. Then dogs were killed and specimens were collected. Selected sections were stained with H&E and evaluated microscopically. Then a total of 36 roots of mandibular premolars from periapical periodontitis model of 3 months were used, roots were filled with ProRoot MTA, glass ionomer cement, and composite resin. Specimens were collected and evaluated microscopically.

Results: In periapical periodontitis models, histological results showed that inflammatory cell infiltrate in pulp lesion. The periodental ligaments were destroyed. Histologically periapical lesions develop rapidly between 1 to 2 weeks and more slowly thereafter. In the specimens filled with different root-end filling materials, inflammation is hardly found in all specimens. There are new cementum deposite in close proximity to the MTA surface, Fibroblasts and collagen fibers arranged parallel to each other between the new cementum and alveolar bone. Fibroblasts and collagen fibres can also been found adjacent to glass ionomer cement, some fibbers connective tissue calcified could also be found. There are fibers connective tissues adjacent to composite resin surface only.

Conclusion: Opening the root to the oral environment for 7-day, the periapical periodontitis model could be established. MTA showed good biocompatibility. Glass ionomer cement showed good tissue toleration, and biocompatibility of composite resin is worst.