Dang D A, Walton R E
Endodoncia. 1990 Oct-Dec;8(4):177-86.
The incidence of vertical root fractures and the amount of root distortion created during lateral condensation of gutta-percha with either D11 spreaders or B-finger pluggers were evaluated in vitro. Fifty-five extracted human, single-rooted teeth were instrumented using the step-back flare technique. Ten teeth served as positive controls (obturation to the point of fracture) and five teeth as negative controls (prepared but not obtured). Strain gauges were attached to the root surfaces. In the experimental group, 20 teeth were obturated using a D11 spreader and 20 with a B-finger plugger. Recordings were made of root distortion (expansion) created during obturation. Then, after sectioning the teeth, root surfaces of obturated samples were examined for fractures under the scanning electron microscope. Only the more tapered spreader, the D11, produces vertical root fractures, although very few in number. Also, the D11 spreader caused greater root distortion than did the B-finger plugger.
在体外评估了使用D11扩锥或B型指状充填器进行牙胶侧向加压时垂直根折的发生率以及产生的牙根变形量。使用逐步后退扩管技术对55颗拔除的人单根牙进行预备。10颗牙作为阳性对照（充填至折断点），5颗牙作为阴性对照（预备但未充填）。应变片附着于牙根表面。在实验组中，20颗牙使用D11扩锥进行充填，20颗牙使用B型指状充填器进行充填。记录充填过程中产生的牙根变形（扩张）。然后，在将牙齿切片后，在扫描电子显微镜下检查充填样本的牙根表面是否有折裂。只有更锥形的扩锥，即D11，会导致垂直根折，尽管数量很少。此外，D11扩锥比B型指状充填器引起的牙根变形更大。
