Reddy Narender, Admala Shilpa Reddy, Dinapadu Sainath, Pasari Srikanth, Reddy Manoranjan P, Rao M S Rama
Senior Lecturer, Department of Conservative and Endodontics, SVS Institute of Dental Sciences, Mahabubnagar, Andhra Pradesh, India.
J Contemp Dent Pract. 2013 Jul 1;14(4):635-43. doi: 10.5005/jp-journals-10024-1377.
To evaluate the efficacy and cleaning ability of Hedstrom files, and ProTaper retreatment instruments in removing gutta-percha from root canals with and without xylene as solvent.
Sixty extracted single rooted human teeth were selected and decoronated, straight access established working length determined 1 mm short of canal, chemomechanical preparation done and obturated with guttapercha and AH plus sealer. Samples were stored for 1 week in humidifier divided into four groups of 15 teeth each. • Group I: Hedstrom files without xylene. • Group II: Hedstrom files with xylene. • Group III: ProTaper retreatment instruments without xylene. • Group IV: ProTaper retreatment instruments with xylene. and the following criteria were assessed - Time taken for initial plunge of instrument into guttapercha. - Time taken for complete removal of gutta-percha to reach working length - Ability of H files and ProTaper retreatment files with/ without xylene to remove gutta-percha in coronal, middle and apical 1/3 of canal. The teeth were grooved in labiolingual cross section, observed under a steromicroscope and scored according to gutta-percha debris left in the canal. Results were evaluated using ANOVA test and multiple comparisons done using Scheffe test.
The least time to reach working length was found with group IV followed by groups III, II and group I respectively. Also the fastest way to remove maximum gutta-percha was group IV followed by groups III, II, and I respectively with a statistically significant difference among all groups. Apical 1/3 has more amount of remaining gutta-percha debris than middle and coronal 1/3 in all groups. The amount of gutta-percha debris in apical 1/3 was least in group IV followed by groups III, II and I respectively.
The better performance of ProTaper rotary instruments has been attributed to their special flute design which tends to pull gutta-percha coronally directing it toward orifice. Also the movements of engine driven instruments produce frictional heat which plasticises gutta-percha and aids in easy removal. Apical third of root canals showed more guttapercha debris compared to coronal and middle 1/3 and has been attributed to the greater anatomic variability and difficulty of instrumentation in the apical area. The existence of deep groves and depressions on dentine walls in this apical 1/3 make them less instrumented areas as it did be difficult to direct the file against the extreme root canal wall.
The fastest technique to remove gutta-percha and the shortest time to reach working length was observed with ProTaper retreatment instruments with xylene followed by ProTaper retreatment files without xylene and Hedstrom files without xylene. After instrumentation for removal of gutta-percha, apical third was found to have more debris compared to coronal and middle 1/3 of the root canal.
评估Hedstrom锉和ProTaper再治疗器械在有或没有二甲苯作为溶剂的情况下从根管中去除牙胶的效果和清洁能力。
选取60颗拔除的单根人牙，去除冠部，建立直线通路，确定工作长度比根管短1mm，进行化学机械预备并用牙胶和AH plus封闭剂充填。样本在加湿器中保存1周，分为四组，每组15颗牙。• 第一组：不使用二甲苯的Hedstrom锉。• 第二组：使用二甲苯的Hedstrom锉。• 第三组：不使用二甲苯的ProTaper再治疗器械。• 第四组：使用二甲苯的ProTaper再治疗器械，并评估以下标准 - 器械初次插入牙胶的时间。 - 完全去除牙胶达到工作长度所需的时间 - 有/无二甲苯的H锉和ProTaper再治疗锉在根管冠部、中部和根尖1/3去除牙胶的能力。将牙齿在唇舌向横截面开槽，在体视显微镜下观察，并根据根管内残留的牙胶碎屑评分。结果采用方差分析进行评估，并使用Scheffe检验进行多重比较。
发现第四组达到工作长度的时间最短，其次分别是第三组、第二组和第一组。同样，去除最多牙胶的最快方法是第四组，其次分别是第三组、第二组和第一组，所有组之间存在统计学显著差异。在所有组中，根尖1/3残留的牙胶碎屑比中部和冠部1/3更多。根尖1/3的牙胶碎屑量在第四组最少，其次分别是第三组、第二组和第一组。
ProTaper旋转器械的更好性能归因于其特殊的凹槽设计，该设计倾向于将牙胶向冠部拉动并导向根管口。此外，发动机驱动器械的运动产生摩擦热，使牙胶塑化并有助于轻松去除。与冠部和中部1/3相比，根管根尖三分之一显示出更多的牙胶碎屑，这归因于根尖区域更大的解剖变异性和器械操作的难度。根尖1/3牙本质壁上存在深槽和凹陷，使它们成为较少器械操作的区域，因为将锉对准根管壁的极端部位很困难。
观察到使用二甲苯的ProTaper再治疗器械去除牙胶的速度最快，达到工作长度的时间最短，其次是不使用二甲苯的ProTaper再治疗锉和不使用二甲苯的Hedstrom锉。在进行去除牙胶的器械操作后，发现根尖三分之一的碎屑比根管冠部和中部1/3更多。
