锥形束CT评价ProTaperUniversal、ProTaperNext和M3的根管成形能力

Cone-beam computed tomography analysis of the canal shaping ability with ProTaper Universal,ProTaper Next and M3 in preparation of curved root canals

目的应用锥形束CT比较ProTaper Universal、ProTaper Next与M3预备弯曲根管的成形效果。方法选取符合标准的上颌第一前磨牙弯曲单根管60个,按弯曲度分为中度弯曲(10°~25°)组和重度弯曲(26°~75°)组,每组30例。依照弯曲程度每组再随机分为3小组,PU组、PN组和M3组(n=10),分别用ProTaper Universal、Pro TaperNext和M3进行根管预备。预备前后进行锥形束CT扫描,记录根管预备时间,预备前后的形态图像,测量距根尖2、5、8mm处根管近、远中侧的根管壁厚度,计算根管偏移量以及轴中心率。结果 PN组、M3组重度弯曲根管预备时间较PU组明显缩短、效率高。重度弯曲根管中,PU组有1根S1发生变形,PN组和M3组器械在预备平均5个根管后都未出现变形。3组均无器械折断。在距根尖孔5mm处,PN组和M3组中、重度弯曲根管内侧牙本质去除量均小于PU组,3组弯曲根管外侧牙本质去除量无明显差异。在距根尖孔2mm处,重度弯曲根管中PN组的偏移量最小,在距根尖孔5mm处,PN组和M3组中、重度弯曲根管偏移量均小于PU组。在距根尖孔5mm处,PN组和M3组重度弯曲根管轴中心率均高于PU组。结论 ProTaper Next和M3预备弯曲根管时能较好地保持原有根管形态,省时省力,值得推广。

Objective To evaluate the shaping ability of ProTaper Universal (PU), ProTaper Next (PN) and M3 in preparation of curved root canals by CBCT (cone-beam computed tomography). Methods Sixty extracted maxillary first premolars were divided into two groups according to the canal curvature:10°-25° group and 26°-75°group. Then, each group was divided into PU group, PN group and M3 group and prepared with three instruments respectively. Canals were scanned by CBCT scanner before and after preparation. The efficacy of canal preparation was analyzed. The width of dentine removed was measured at three points (2 mm, 5 mm and 8 mm to root tip). The apical transportation indexes and the centring ratio values were recorded. Results PN group and M3 group needed less time in preparation and showed more efficiency than those of PU group in 26°-75° groups. One of root canals in PU group appeared deformation, neither PN group nor M3 group appeared deformation after 5 root canal preparations in average. None instrument was broken in three groups. PU group removed more materials at internal walls than PN group and M3 group at internal walls of root canals in 5 mm from the apex.There was no difference in the offset of the external walls of root canals. Compared with the offset of the internal and external walls of root canals in 2 mm from the apex, the apical transportations prepared by the PN group were less than those of M3 group and PU group in 26°-75° groups. Compared with the offset of the internal and external walls of root canals in 5 mm from the apex, the apical transportations prepared by the PN group and M3 group were less than those of PU group, and their centring ratio values were greater than those of PU group in 26°-75°groups. Conclusion ProTaper Next and M3 tested in this study are effective and time-saving in shaping curved root canals. The results indicate that both ProTaper Next and M3 are comparable to optimally enlarge root canal.