De Rossi Andiara, Silva Léa A B, Leonardo Mario R, Rocha Lenaldo B, Rossi Marcos A
Department of Pathology, University of São Paulo and State University of São Paulo, Brazil.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2005 May;99(5):628-36. doi: 10.1016/j.tripleo.2004.07.018.
To evaluate the healing of experimentally induced chronic periapical lesions in dogs at 30, 75, and 120 days after root canal instrumentation with rotary NiTi files or manual K-files, with or without a calcium hydroxide/1% chlorhexidine paste intracanal dressing.
The second, third, and fourth mandibular premolars and the second and third maxillary premolars of 5 dogs (12 to 18 months of age, weighing 8 to 15 kg) were selected for treatment (a total of 82 root canals). After pulp removal, the root canals were left exposed to the oral cavity for 7 days to allow microbial contamination, after which the root canals were sealed with ZOE cement until periapical lesions were confirmed with radiography. Group I and II teeth were instrumented with manual K-files using the crown-down technique. In group III and IV teeth, NiTi rotary files were used. The apical delta was perforated by using #20 to #30 K-files at the length of the tooth, thus creating a standardized apical opening. The apical stop was enlarged to size 70, with 2.5% sodium hypochlorite irrigation at each file change. Teeth in groups II and IV were dressed with calcium hydroxide (Ca(OH) 2 )/1% chlorhexidine (CHX) paste for 15 days before root filling. Group I and III teeth did not receive an intracanal dressing. The access openings of the teeth were permanently restored with silver amalgam condensed on a glass ionomer cement base. Pairs of standardized periapical radiographs were taken at the beginning of the treatment (0 days) and at 30, 75, and 120 days after filling.
There was no significant difference in the rate of radiographic healing of the periapical lesions between manual and rotary instrumentation. Radiographs taken at 120 days showed that the treatment with Ca(OH) 2 /1% CHX paste resulted in a significant reduction in mean size of the periapical lesions in comparison to single-session treatment. These findings were also true for histologic observations.
The findings support the hypothesis that, regardless of the instrumentation technique (manual or rotary), the use of an intracanal dressing is important in the endodontic treatment of dog's teeth with experimentally induced chronic periapical lesions.
评估在使用旋转镍钛锉或手动K锉进行根管预备后30、75和120天，犬实验性诱导慢性根尖周病变的愈合情况，根管内是否使用氢氧化钙/1%洗必泰糊剂敷料。
选择5只犬（12至18月龄，体重8至15千克）的下颌第二、三、四前磨牙及上颌第二、三前磨牙进行治疗（共82个根管）。牙髓摘除后，根管暴露于口腔7天以允许微生物污染，之后用氧化锌丁香油水门汀封闭根管，直至通过X线片确认根尖周病变。第一组和第二组牙齿采用冠向下技术用手动K锉进行预备。第三组和第四组牙齿使用镍钛旋转锉。在牙齿长度处用#20至#30 K锉穿孔根尖孔，从而形成标准化的根尖开口。每次更换锉时用2.5%次氯酸钠冲洗，将根尖止点扩大到70号。第二组和第四组牙齿在根管充填前用氢氧化钙（Ca(OH)₂）/1%洗必泰（CHX）糊剂处理15天。第一组和第三组牙齿未进行根管内敷料处理。牙齿的髓腔入口用银汞合金在玻璃离子水门汀基底上加压永久充填。在治疗开始时（0天）以及充填后30、75和120天拍摄标准化根尖X线片对。
手动预备和旋转预备之间根尖周病变的X线愈合率无显著差异。120天时拍摄的X线片显示，与单次治疗相比，用Ca(OH)₂/1% CHX糊剂治疗导致根尖周病变的平均大小显著减小。组织学观察结果也是如此。
这些发现支持以下假设，即无论预备技术（手动或旋转）如何，根管内敷料在犬实验性诱导慢性根尖周病变的牙髓治疗中都很重要。
