背景:根管治疗后进行桩核冠修复牙齿的过程中, 根管充填不理想或是不良的桩核冠修复可造成材料与牙体间的微渗漏, 导致根尖周组织二次感染, 影响牙体修复远期效果.目的:通过葡萄糖微渗漏模型比较不同桩道预备时机及剩余根充物长度对微渗漏的影响.方法:收集中山大学孙逸仙纪念医院正畸科近期拔除的单、直根管下颌前磨牙86颗, 分8组干预:阳性对照组 (n=10) 行根管预备;阴性对照组 (n=10) 根管预备、充填后不进行桩道预备;A1组 (n=11) 根管充填后即刻进行桩道预备, 保留根管内4 mm充填物;B1组 (n=11) 根管充填后即刻进行桩道预备, 保留根管内5 mm充填物;C1组 (n=11) 根管充填后即刻进行桩道预备, 保留根管内6mm充填物;A2组 (n=11) 根管充填后1周进行桩道预备, 保留根管内4mm充填物;B2组 (n=11) 根管充填后1周进行桩道预备 (即延迟桩道预备), 保留根管内5 mm充填物;C2组 (n=11) 根管充填后1周进行桩道预备, 保留根管内6 mm充填物.桩道预备48 h后, 扫描电镜观察根管壁与充填物结合情况, 采用葡萄糖微渗漏模型检测各组样本从冠方向根方渗漏的葡萄糖量.结果与结论: (1) 扫描电镜显示, C1组充填物与根管壁连接最紧密, A2组充填物与根管壁间微缝隙最明显; (2) 葡萄糖微渗漏量测定显示, A2组微渗漏量大于A1组 (P <0.05), B2组微渗漏量大于B1组 (P <0.05), C1组微渗漏量与C2组比较无差异 (P> 0.05);A1组、B1组、C1组微渗漏量比较无差异 (P> 0.05), B2组微渗漏量与A2组、C2组比较无差异 (P> 0.05), A2组微渗漏量大于C2组 (P′<0.017); (3) 结果表明, 即刻桩道预备在减少微渗漏方面优于延迟桩道预备;即刻桩道预备后, 保留不同长度充填物对微渗漏无影响, 而延迟桩道预备时应至少保留5 mm根充物, 以减少微渗漏的发生.%BACKGROUND: Poor root canal filling or poor post-core crown restoration can cause microleakage between the implant material and the tooth, leading to secondary infection of the periapical tissue and affecting long-term effect of tooth restoration. OBJECTIVE: To analyze the microleakage in a glucose penetration model when post space preparation is performed with different timing and remaining lengths. METHODS: Eighty-six freshly extracted mandibular premolars from the Orthodontics Department of Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University were randomly divided into eight groups: positive control group (n=10) undertook root canal preparation; negative control group (n=10) undertook root canal preparation and filling but not post space preparation; A1, B1 and C1 groups (n=11 per group) were subjected to root canal filling immediately followed by post space preparation with the filling material of 4 mm, 5 mm, and 6 mm in length, respectively; A2, B2 and C2 groups were subjected to root canal filling and 1 week after filling, the three groups underwent post space preparation with the filling material of 4, 5 and 6 mm in length, respectively. At 48 hours after post space preparation, the integration of root canal wall and filling material was observed by scanning electron microscopy. The glucose microleakage model was used to detect the amount of glucose leaking from the crown to the root in each group. RESULTS AND CONCLUSION: (1) Under the scanning electron microscope, the fillings were most tightly bonded to the root canal wall in C1, while microcracks were most apparent in A2. (2) According to the measurement of glucose penetration model, A2 showed more microleakage than A1 (P < 0.05), B2 showed more microleakage than B1 (P < 0.05), and there was no statistically significant difference between C1 and C2 (P> 0.05). No significant difference was found among A1, B1 and C1 (P> 0.05), B2 showed no statistical difference in the microleakage from A2 and C2 (P> 0.05), but A2 showed more microleakage than C2 (P′ < 0.017). These results indicate that immediate post space preparation is superior to delayed preparation in reducing the microleakage. For immediate post space preparation, the remaining length of the filling material has no effect on the microleakage, but for delayed preparation, the filling material of at least 5 mm in length should be preserved.
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