Loney R W, Kotowicz W E, McDowell G C
Department of Restorative and Prosthetic Dentistry, University of Saskatchewan, College of Dentistry, Saskatoon, Canada.
J Prosthet Dent. 1990 May;63(5):506-12. doi: 10.1016/0022-3913(90)90066-l.
The effect of a metal collar on stress distribution with cast post and cores was studied by using three-dimensional photoelastic models of maxillary canine teeth of average dimensions. Standardized parallel post and cores were cemented into the models, with half of the samples incorporating a 1.5 mm metal collar. A 400 gm load was applied to the cingulum of the cores and stresses were frozen in the models. The posts were removed, the teeth were sectioned, and stresses were measured with a circular polariscope. In both groups the greatest stress concentration was found at the lingual apex of the post. On a point by point basis, stresses were higher in the collared specimens. Variation in stress magnitude among five preselected points was greater within the noncollared group.
通过使用平均尺寸的上颌尖牙的三维光弹性模型，研究了金属颈环对铸造桩核应力分布的影响。将标准化的平行桩核粘结到模型中，其中一半样本包含一个1.5毫米的金属颈环。在桩核的舌隆突处施加400克的载荷，并将应力冻结在模型中。取出桩，将牙齿切片，并用圆偏振光镜测量应力。在两组中，最大应力集中均出现在桩的舌侧根尖处。逐点来看，有颈环的标本中的应力更高。在无颈环组中，五个预选点之间的应力大小变化更大。
