锥束CT评价两种镍钛器械预备根管后根管偏移的实验研究

Cone-beam computed tomography analysis of the canal transportation after mechanical preparation with two different rotary nickel-titanium systems

目的:以锥束CT为研究工具评价Mtwo、Protaper两种镍钛器械对根管偏移的控制能力和中心定位能力。方法:将按纳入标准收集的24个离体牙随机分为两组,其中G1组用Protaper按crown-down法预备至F2;G2组用Mtwo按标准法预备至0.06/#25。预备前后均用锥束CT对近中、远中根管壁的厚度进行测量,然后利用Gambill提出的公式进行根管偏移和轴中心率的计算。结果:Protaper组与Mtwo组根管偏移的均值分别为(0.110±0.076)mm和(0.076±0.049)mm;轴中心率的均值分别为0.604±0.230和0.666±0.163,两组相比,无论是根管偏移量还是轴中心率,差异均无统计学意义(P>0.05)。结论:Mtwo、Protaper在预备弯曲根管时均具有较好的安全性;锥束CT可在无创情况下评价预备器械对根管成形能力。

AIM： To evaluate the apical canal transportation and centring ability of NiTi rotary instrument Mtwo and Protaper after root canal preparation by cone beam computed tomography（CBCT）.METHODS： A total of twenty-four human teeth were randomly assigned to two groups,Protaper group（G1） and Mtwo group（G2）.Crown-down technique was used in protaper group,while Mtwo group was treated with routine preparation technique.CBCT scans were taken before and after biomechanical preparation.Canal transportation and centralizing ability were measured with reference to the distance between the noninstrumented portion of the root canals and the mesial and distal periphery of the root,compared with images obtained after the preparation.RESULTS： Canal transportation after prepation with protaper was 0.110±0.076mm and after prepation with Mtwo was 0.076±0.049 mm.The centring ratio values after prepation with protaper was 0.604 ±0.230,and after the Mtwo was 0.666±0.163,with no significan difference between the two groups.CONCLUSION：Cone beam computed tomography can be used as a new methodology for deviation analyses.Mtwo and Protaper tested in this study are effective and safe in shaping curved canal.