Zevallos-Quiroz Cesar Andre, Perez Ivan E, Garcia-Rupaya Carmen Rosa
Private Practice, Specialist in Endodontics in Lima, Peru.
Private Practice, Specialist in Oral and Maxillofacial Radiology In Lima, Peru.
Iran Endod J. 2019 Spring;14(2):115-121. doi: 10.22037/iej.v14i2.23644.
The aim of the present study was to compare the efficacy of four NiTi instruments with different properties (shape memory and control memory), in both rotary and reciprocating motions, during retreatment procedures.
Mesial canals of thirty-two mandibular molars were instrumented, obturated, and then scanned with" Cone-beam Computed Tomography" (CBCT). Teeth were randomly divided into 4 groups (=8) according to each system: "Shape Memory" (SM) instruments including Reciproc (R25 file) and ProTaper Next (X3 and X2 file), "Controlled Memory" (CM) instruments including WaveOne Gold (Primary file) and Hyflex (30.06 and 25.06 file). The specimens were rescanned after retreatment procedures. The volume of the residual material left inside the canals, the operating time and the fractured files were analyzed. ANOVA and student -tests were used for statistical analysis.
There were no significant differences in the percentage of the residual filling material or requiring time amongst different groups of instruments (>0.05). However, CM instruments presented the highest frequency of fractured files [2 SM instruments (12.5%) and 7 CM instruments (43.75%)] with a significant difference (=0.023).
This study showed that CM and SM instruments can remove filling materials from mandibular mesial root canals during retreatment procedures; nonetheless the CM instruments had a higher frequency of fractured files. No system was able to completely remove the filling materials. Therefore, additional procedures and techniques are needed to improve root canal cleanliness.
本研究的目的是比较四种具有不同特性（形状记忆和控制记忆）的镍钛器械在再治疗过程中旋转和往复运动时的疗效。
对32颗下颌磨牙的近中根管进行预备、充填，然后用锥形束计算机断层扫描（CBCT）进行扫描。根据每个系统将牙齿随机分为4组（每组8颗）：“形状记忆”（SM）器械组，包括Reciproc（R25锉）和ProTaper Next（X3和X2锉）；“控制记忆”（CM）器械组，包括WaveOne Gold（初尖锉）和Hyflex（30.06和25.06锉）。再治疗后对标本进行重新扫描。分析根管内残留材料的体积、操作时间和锉针折断情况。采用方差分析和学生t检验进行统计学分析。
不同器械组之间残留充填材料的百分比或所需时间无显著差异（P>0.05）。然而，CM器械组锉针折断的频率最高[2根SM器械（12.5%）和7根CM器械（43.75%）]，差异有统计学意义（P=0.023）。
本研究表明，CM和SM器械在再治疗过程中均可从下颌近中根管中去除充填材料；尽管如此，CM器械组锉针折断的频率更高。没有一个系统能够完全去除充填材料。因此，需要额外的程序和技术来提高根管清洁度。
