Beltz Richard E, Torabinejad Mahmoud, Pouresmail Manucher
Division of Biochemistry, School of Dentistry, Loma Linda University, CA 92350, USA.
J Endod. 2003 May;29(5):334-7. doi: 10.1097/00004770-200305000-00004.
Necrotic bovine pulp and dentin were used in this study as model tissues to represent the organic and inorganic components of the smear layer present in instrumented root canals. The capabilities of endodontic irrigants to dissolve pulverized forms of these tissues were compared. Lyophilized tissue samples were mixed for 2 h at 37 degrees C with MTAD, three concentrations of sodium hypochlorite (NaOCl), 17% EDTA, or isotonic saline. Undissolved tissues were rinsed with water and lyophilized. The change in tissue weight after exposure to an irrigant was measured to quantify solubilization. The results showed that various concentrations of NaOCl removed organic components of pulp and dentin effectively. As pulp solubilizers 5.25% and 2.60% NaOCl were equal (>90%), and 5.25% NaOCl was capable of dissolving virtually the entire organic component of dentin. EDTA was capable of solubilizing inorganic material in dentin and organic material in pulp and likely also in dentin. It dissolved >70% of the dentin and >51% of the pulp. The solubilizing effects of MTAD on pulp and dentin were somewhat similar to those of EDTA. The major difference between the actions of these solutions was a high binding affinity of doxycycline present in MTAD for the dentin.
本研究使用坏死的牛牙髓和牙本质作为模型组织，以代表根管预备后根管内玷污层的有机和无机成分。比较了根管冲洗剂溶解这些组织粉碎形式的能力。将冻干的组织样本在37℃下与MTAD、三种浓度的次氯酸钠（NaOCl）、17%乙二胺四乙酸（EDTA）或等渗盐水混合2小时。未溶解的组织用水冲洗并冻干。测量暴露于冲洗剂后组织重量的变化以量化溶解情况。结果表明，不同浓度的NaOCl能有效去除牙髓和牙本质的有机成分。作为牙髓溶解剂，5.25%和2.60%的NaOCl效果相当（>90%），5.25%的NaOCl几乎能溶解牙本质的全部有机成分。EDTA能够溶解牙本质中的无机物质以及牙髓中可能还有牙本质中的有机物质。它溶解了>70%的牙本质和>51%的牙髓。MTAD对牙髓和牙本质的溶解作用与EDTA有些相似。这些溶液作用的主要区别在于MTAD中存在的强力霉素对牙本质具有高结合亲和力。
