Davy D T, Dilley G L, Krejci R F
J Dent Res. 1981 Jul;60(7):1301-10. doi: 10.1177/00220345810600070301.
A theoretical investigation has utilized the finite element technique to analyze mechanical stress patterns in a reconstructed maxillary central incisor. A series of designs for endodontic dowel posts incorporated into prosthesis has been comparatively evaluated. For the load condition considered, the results show that minor changes in the stress patterns are produced by the post diameter, length, and taper variations considered. 1. In general, larger post diameters decrease the maximum stresses for both the cylindrical and tapered designs. Variation of diameters over a 15% range produced stress variations of about 8%. 2. The effect of post length on the highest stresses in bending was less than the diameter changes. The real effect of the length changes was to change the location of the stress concentrations that occurred at the post apex in all cases. 3. The effect of taper was found to be slight if the local tapered-post diameter was comparable to the cylindrical post diameter in the high-stress region. 4. For the load considered in this study, the tapered-post design experienced slightly higher tensile and slightly lower shear stresses than the cylindrical post. 5. Using the peak stresses in the dentin and at the dentin-post interface as a criterion, the cylindrical post with the largest diameter is the best design among those examined.
一项理论研究利用有限元技术分析了上颌中切牙重建后的机械应力模式。对纳入假体的一系列根管桩设计进行了比较评估。对于所考虑的载荷条件，结果表明，所考虑的桩直径、长度和锥度变化会产生应力模式的微小变化。1. 一般来说，对于圆柱形和锥形设计，较大的桩直径会降低最大应力。直径在15%范围内变化会产生约8%的应力变化。2. 桩长度对弯曲时最高应力的影响小于直径变化。长度变化的实际影响是改变了所有情况下桩尖处应力集中的位置。3. 如果局部锥形桩直径与高应力区域的圆柱形桩直径相当，则发现锥度的影响很小。4. 对于本研究中考虑的载荷，锥形桩设计的拉伸应力略高于圆柱形桩，剪切应力略低于圆柱形桩。5. 以牙本质和牙本质 - 桩界面处的峰值应力为标准，在所研究的设计中，直径最大的圆柱形桩是最佳设计。
