The study on direct pulp capping with experimental absorbable and hard tissue inductive material

评价了实验室和商业化可生物降解接枝石膏的组成和性能。实验生物降解石膏比商业石膏更多孔。实验用生物降解石膏的纯度和降解率均高于商品石膏。实验结果表明，这些差异可能影响了石膏的体内组织反应和吸收能力。对照组采用增强丁香酚水门汀作为根端充填材料。骨水泥在术后4周才被吸收，术后4周仍观察到炎症。实验组用实验植骨石膏作为根端充填材料。实验石膏于术后2周吸收，术后4周炎症消退，通过大鼠皮下实验和直接盖髓实验，评价实验石膏与人重组形态发生蛋白2（rh-BMP 2）联合应用对硬组织的组织反应和诱导活性。皮下实验表明，实验石膏与rh-BMP-2或不与rh-BMP-2均具有异位硬组织诱导潜能。rh-BMP-2的加入促进了硬组织的形成。实验性石膏直接盖髓在术后7 d引起轻度炎症反应，但在术后28 d引起纤维化，盖髓材料下方部分硬组织形成。rh-BMP-2的加入促进了硬组织的形成。

The composition and properties of experimental and commercial biodegradable grafting gypsum was evaluated. The experimental biodegradable gypsum was more porous than the commercial one. The purity and decay rate of experimental biodegradable gypsum was higher than commercial one. It was suggested that these differences may affect me tissue reaction and absorbability of the experimental gypsum in vivo.The biocompatibility of the experimental gypsum was tested at the periapical portion of the replanted rat incisor. In the control group, the reinforced eugenol cement was filled as root end filling material. The cement was not absorbed until four weeks after operation and the inflammation was still observed until four weeks after operation. In the experimental group, the experimental bone grafting gypsum was filled as root end filling material. The experimental gypsum was absorbed until two weeks after operation and the inflammation went out until four weeks after operation.To evaluate tissue response and inductance activity of hard tissue by experimental gypsum with or without human recombinant morphogenetic protein 2(rh-BMP 2), subcutaneous test and direct pulp capping test in rats was carried. The subcutaneous test revealed that experimental gypsum with or without rh-BMP 2 have ectopic hard tissue induction potency. The addition of rh-BMP 2 to experimental gypsum promoted the formation of the hard tissue. The application of experimental gypsum to direct pulp capping caused slightly inflammatory response in 7 days after operation, but caused fibrosis and partial hard tissue formation below the capping materials in 28 days after operation. The addition of rh-BMP 2 to experimental gypsum promoted the formation of the hard tissue.