摘要
目的：观察纳米材料的组织相容性和根尖封闭性。
方法：1. 纳米材料组织相容性：将4个填有不同实验材料的硅胶管和1个空硅胶管（作为空白对照）置于SD大鼠皮下组织内。第1组：氧化锌丁香油糊剂组（ZOE）（对照组）；第2组：纳米氧化锌糊剂组（N-ZO）；第3组：羟磷灰石糊剂组（HA）；第4组：纳米羟磷灰石糊剂组（NHA）；空白对照作为炎症分级的评价标准。分别于2周和12周后处死动物，取下包括皮肤、皮下组织的植入块，仔细修整组织块并取出种植物，10%的中性福尔马林固定，石蜡包埋，沿植入物长轴切片，HE染色，镜下观察组织学反应，并根据炎症分级情况评价组织相容性。2. 纳米材料根尖封闭性：40颗离体单根管牙牙根，采用逐步后退法预备根管，随机分为四组，每组10个。每一组的根管用牙胶尖和一种根管糊剂，采用侧方加压法进行充填。第1组：氧化锌丁香油糊剂组（ZOE）（对照组）；第2组：纳米氧化锌糊剂组（N-ZO）；第3组：羟磷灰石糊剂组（HA）；第4组：纳米羟磷灰石糊剂组（NHA），另有4颗未充填的牙根分别作为阴性和阳性对照。进入的洞口用磷酸锌水门汀充填。使糊剂在37℃、100％湿度环境中凝固48小时，然后经染色、脱钙、脱水，用透明牙法观察染料渗入的深度。根据根尖微渗漏情况，评价根尖封闭性。
结果：2周时，四种材料的炎症分级情况有显著性差异（P<0.01），HA组的炎症分级情况优于ZOE组（对照组）（P<0.01）；12周时，四种材料的炎症分级情况有显著性差异（P<0.01），N-ZO组、HA组和NHA组的炎症分级情况优于ZOE组（对照组）（P<0.01）。四种材料的根尖微渗漏有显著差异（P<0.01）；N-ZO组、HA组和NHA组的根尖微渗漏低于ZOE组（对照组）（P<0.01），即N-ZO、HA、NHA的根尖封闭性优于ZOE组；N-ZO组微渗漏低于NHA组，有统计学意义（P<0.05），表明N-ZO的根尖封闭性优于NHA。
结论：纳米氧化锌糊剂、羟磷灰石糊剂和纳米羟磷灰石糊剂具有良好的组织相容性和根尖封闭性，可以作为根管封闭剂用于根管充填。
Aim: To observe histocompatibility and apical sealing ability of two kinds of nanomaterial.
Method: Histocompatibility: Methyl-silicone rubber tubes filled with experimental materials of four groups and empty methyl-silicone rubber tubes were implanted into hypodermic tissues of the 10 SD rats of 4 tubes filled with different experimental materials and 1 empty one each. Group 1: filled with zinc oxide-eugenol sealer (ZOE) (the control group); group 2: filled with nano-zinc-oxide sealer(N-ZO); group 3: filled with hydroxyapatite sealer (HA); group 4: filled with nanohydroxyapatite sealer (NHA). Empty tubes which did not filled any material as empty controls were used to assess the grade of inflammation.After 2 weeks and 12 weeks of implantation, the histological reactions were examined under microscope. The histocompatibility of the four kinds of materials is assessed according to the grades of inflammation. Apical sealing ability: 40 roots of single-rooted teeth were prepared using step-back technique and randomly assigned to one of four groups of ten roots each. The root canals were obturated with gutta-percha and one of the sealers by the lateral condensation technique. Group 1: filled with zinc oxide-eugenol sealer and gutta-percha (ZOE) (the control group); group 2: filled with nano-zinc-oxide sealer and gutta-percha (N-ZO); group 3: filled with hydroxyapatite sealer and gutta-percha (HA); group 4: filled with nanohydroxyapatite sealer and gutta-percha (NHA). In addition there were 4 roots which did not filled as negative and positive controls. The access opening was filled with zinc phosphate cement. The sealer was allowed to set in 100% humidity and at 37℃for 48 hours. The roots, except for the apical 2mm, were coated with sticky wax. The roots were stained with ink, decalcified、dehydrated, and then placed in methysalicylate to make them transparent. The linear dye penetration was assessed using a stereomicroscope ×16 magnification. The apical sealing ability of the materials were assessed according to the length of dye penetration.
Results : At 2 weeks, there were statistical difference among the grades of inflammation of four kinds of materials (P<0.01), the grades of inflammation of HA were more milder than that of ZOE (the control group) (P<0.01); at 12
weeks, there were statistical difference among the grades of inflammation of four kinds of materials (P<0.01), the grades of inflammation of N-ZO、HA and NHA were more milder than that of ZOE (the control group) (P<0.01). The measured results for the distance of dye penetration showed among four groups differed significantly(P<0.01), the distance of dye penetration of N-ZO、HA and NHA were less than that of ZOE(the control group) (P<0.01); the distance of dye penetration of N-ZO was less than that of NHA(P<0.05).
Conclusion: Nano-zinc-oxide、hydroxyapatite and nanohydroxyapatite have favorable histocompatibility and excellent apical sealing ability, so they are suitable for root filling as root canal sealers.
引文
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