Abstract:

 Objective    To comparatively study the apical sealing ability of the Elements Obturation Unit system with different heating temperatures and two root canal sealers. Methods    Totally 120 single-canal extracted teeth were shaped using the Pro-Taper Ni-Ti rotary instruments with the Crown-Down technique to F3. All teeth were randomly divided into 8 groups. The experimental groups were obturated by the continuous wave of condensation technique. The apical part was made with nonstandard gutta-percha point，which was coated with endomethasone ivory or AH-plus as root canal sealer，and the Elements Obturation Unit system was setted with four heating temperatures： 150，160，180 and 200 ℃ to obturate the coronal part . After that， teeth were demineralized，dehydrated and cleared. Leakage was measured using dyeing penetration and the micro-structure between walls of root canal and the sealers were observed by SEM. Results    For the seal ability of obturation，AH-Plus had better seal ability than the endomethasone ivory groups and there was statistically significant difference between them and the most leakage was observed when the Elements Obturation Unit system was setted into 150℃，but there was significant difference among the 160，180 and 200 ℃ groups（P > 0.05）. Conclusion    The apical sealing ability of the Elements Obturation Unit system setted with 160，180 and 200 ℃ is better than that with 150 ℃. The higher temperature setting，the more thermal damage to periodontal tissue，so we must be cautious to set the temperature of 200℃. We suggest that AH-Plus should be used to improve the apical seal ability and regulate the clinical operation.

Key words: root canal obturation, continuous wave of condensation technique, apical micro-leakage, dye penetration

摘要：

目的    对比研究Elements Obturation Unit热牙胶系统在不同加热温度下及使用两种不同糊剂时的根尖封闭能力。方法    本研究于2014年1月至2014年10月在青岛市口腔医院进行。收集120颗离体单根管牙，机用ProTaper镍钛锉采用冠向下技术预备至F3，然后随机分为8组，均使用连续波热牙胶垂直加压技术充填根管。根尖区充填所用的大锥度牙胶尖分别配合美松和AH-Plus 2种糊剂，Elements Obturation Unit热牙胶系统以150、160、180、200 ℃ 4组不同温度加热牙胶，进行根管冠方充填，根管充填后的各组实验牙行染色及透明化处理后，对染料渗入长度进行分析，并通过扫描电镜观察根尖区根管充填材料与根管壁之间的结合形态。 结果                    AH-Plus组的染料渗入长度明显小于美松组，差异有统计学意义（P < 0.05）。Elements Obturation Unit系统设定150 ℃时，微渗漏值相对较大，与其他温度组比较差异有统计学意义（P < 0.05）。结论    Elements Obturation Unit热牙胶系统在160、180、200 ℃的工作温度下进行根管充填的根尖封闭能力优于150 ℃。但考虑到设定温度越高越会对牙周组织造成热损伤，因此200 ℃的工作温度设定应谨慎选择，且在临床操作中建议使用AH-Plus糊剂，以提高根尖封闭性能。

关键词: 根管充填术, 连续波热牙胶充填技术, 根尖微渗漏, 染料渗透法