Martínez-Insua A, da Silva L, Rilo B, Santana U
School of Dentistry, Faculty of Medicine and Odontology, Santiago de Compostela University, Spain.
J Prosthet Dent. 1998 Nov;80(5):527-32. doi: 10.1016/s0022-3913(98)70027-7.
The survival of pulpless teeth restored with a post and core system is a controversial issue.
This study compared the fracture resistance of 2 types of restorations: teeth restored with prefabricated carbon-fiber posts and composite cores to cast dowel-core restored teeth.
A total of 44 recently extracted sound premolars were randomly distributed into 2 equal groups: group I, restored with prefabricated carbon-fiber post and a composite core; and group II, with custom-cast type III gold alloy post and cores. The size and shape of the posts were identical in the 2 groups. All teeth were fully covered with a nonprecious cast crown. Fracture resistance was measured by applying a point force at 45 degrees to the long angle of the tooth.
Mean fracture threshold was 103.7 +/- 53.1 kg for group I versus 202.7 +/- 125.0 kg for group II (differences significant with P = .003). In group II, however, fracture nearly always affected the tooth itself, whereas in group I, the post-core nearly always failed first.
Significantly higher fracture thresholds were recorded for the cast post and core group. Teeth restored with cast posts typically showed fracture of the tooth, although at loads rarely occurring clinically.
采用桩核系统修复的无髓牙的存活率是一个存在争议的问题。
本研究比较了两种修复体的抗折性：用预制碳纤维桩和复合树脂核修复的牙齿与铸造桩核修复的牙齿。
总共44颗近期拔除的健康前磨牙被随机分为两组，每组数量相等：第一组用预制碳纤维桩和复合树脂核修复；第二组用定制铸造的Ⅲ型金合金桩和核修复。两组桩的尺寸和形状相同。所有牙齿均用非贵金属铸造全冠修复。通过在与牙齿长轴呈45度角的方向施加集中载荷来测量抗折性。
第一组的平均折裂阈值为103.7±53.1千克，而第二组为202.7±125.0千克（差异显著，P = 0.003）。然而，在第二组中，折裂几乎总是发生在牙齿本身，而在第一组中，桩核几乎总是先发生折断。
铸造桩核组的折裂阈值显著更高。用铸造桩修复的牙齿通常表现为牙齿折裂，尽管在临床上很少出现这种载荷情况。
