Murgel C A, Walton R E
College of Dentistry, The University of Iowa, Iowa City.
Endod Dent Traumatol. 1990 Dec;6(6):273-8. doi: 10.1111/j.1600-9657.1990.tb00431.x.
The effect of lateral condensation using different tapered spreaders was evaluated. Curved mesiobuccal roots of maxillary molars were step-back prepared. Strain gauges applied to the root surfaces measured dentin deformation (distortion) during controlled lateral condensation with either fine finger or D11 spreaders. After obturation, roots were cross sectioned and analyzed under the stereomicroscope to detect the presence and pattern of fractures. The results showed no statistical difference between spreader designs as to mean distortion and the incidence of fractures; however several specimens in the D11 group showed high root distortion measurements. When fractures occurred, there were no consistent patterns of fracture in either spreader group. In conclusion, although there were no significant differences in mean deformation or fracture incidence in curved roots between the spreaders, the roots showing high deformation readings in the D11 group may be more susceptible to future vertical root fractures.
评估了使用不同锥形扩孔钻进行侧向加压充填的效果。对上颌磨牙的近中颊侧弯曲根进行逐步后退预备。将应变片贴于牙根表面，测量使用细手指形或D11扩孔钻进行控制性侧向加压充填时牙本质的变形（扭曲）情况。充填后，将牙根进行横断面剖切，并在体视显微镜下分析，以检测根折的存在情况及模式。结果显示，就平均变形和根折发生率而言，不同扩孔钻设计之间无统计学差异；然而，D11组的几个标本显示出较高的牙根变形测量值。当发生根折时，两组扩孔钻组均未出现一致的根折模式。总之，尽管不同扩孔钻在弯曲牙根的平均变形或根折发生率方面无显著差异，但D11组中显示高变形读数的牙根可能更易发生未来的垂直根折。
