Synthesis And Characterization Of Zirconium Mesoporous Materials And Its Application In Root Canal Sealer

Pulp disease, Periapical diseases, Pulp necrosis are the main causes to induce early loss of teeth. Root canal therapy is an effective method in preserving bad tooth. Success or failure of root canal therapy is strongly related to the root canal filling materials.In this paper, the preservable calcium phosphate-based root canal sealer was synthesized by evenly stirring the mixture of apatite powders, humectants, gelling agent, liquid medium and developer. Mesoporous materials, as a developer, were synthesized by the surfactant-assisted route under the hydrothermal condition. The materials were charged with Metronidazole, an anti-inflammatory drug. Chemical stability and radiopacity of developer were studied by FTIR,SAXS,UV-vis. Crystalline form, microstructure and physicochemical properties of the sealer were investigated by XRD, ESEM and FTIR, respectively. And the cytotoxicity was evaluated by MTT method.The results showed doped mesoporous zirconia with ordered pore-arrangement was synthesized in (NH₄)₂SO₄ aqueous solutions by using cheap inorganic salt. The pore size is about 2.0 nm. The non-aggregated metronidazole molecules are self-organized on the channel of mesoporous materials in the form of physical absorption by agitating magnetically. Zirconium oxide containing calcium featured high adsorption capacity because of its large pore size. The results of drug release in situ showed the materials have good sustained drug release effect. The root canal filling materials developed from CPC showed good radiopaque and sealing abilities. Furthermore, the workability conformed to ISO 6876: 2001(E) standards. A preservable paste could be premixed and kept in the container with 4℃, 50%RH, and the physicochemical properties and microstructure almost didn't change in 3 months. When the paste was injected into root canal, it could cure in 45～55h and gradually transform into non-stoichiometric hydroxyapatite and release metronidazole for a few days in vivo to inhibit the growth of some bacteria species. The MTT assay showed the paste had good biocompatibility.