An in vitro study of the fracture resistance and the incidence of vertical root fracture of pulpless teeth restored with six post-and-core systems
An in vitro study of the fracture resistance and the incidence of vertical root fracture of pulpless teeth restored with six post-and-core systems
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DOI：
10.1016/s0022-3913(99)70267-2
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发表时间：
1999-03-01
影响因子：
4.6
通讯作者：
Morgano, SM
中科院分区：
文献类型：
--
作者：
Sirimai, S;Riis, DN;Morgano, SM
问题陈述。桩和核通常需要无髓牙，以提供完整牙冠的固位和阻力形式。然而，传统的桩可能会增加潜在的根管治疗。本研究比较了用聚乙烯编织纤维（Ribbond）修饰的桩核系统与传统桩核系统处理的离体牙对牙根纵裂的抵抗力。材料和方法。对60颗上颌中切牙进行根管预备，并进行全冠预备。每颗牙的冠状部分被切断，6桩核系统进行了研究。将标本固定在丙烯酸树脂块中，根部覆盖一层聚乙烯基硅氧烷。以130度的角度施加载荷，并用万能试验机测量。采用Student-Newman-Keuls分组单因素方差分析和卡方分析进行统计学处理。铸造桩和核心导致显着更高的故障阈值比所有其他的，除了预制的，尺寸，平行边桩复合核心。快速桩组中的所有失败均涉及牙齿断裂，而70%的具有大尺寸平行侧桩和复合材料核的牙齿由于牙齿断裂而失败，30%的牙齿经历了核断裂。编织纤维桩核系统的强度明显低于其他所有系统，并表现出明显较少的垂直根管。聚乙烯编织纤维和复合树脂无预成桩时，牙根纵裂发生率显著升高，但平均破坏载荷最低。直径较小的预制桩与聚乙烯编织纤维和复合材料芯相结合，提高了抗失效能力。6种桩核系统中，传统铸造桩核的强度最高。
Statement of problem. Posts and cores are often required with pulpless teeth to provide retention and resistance form for complete crowns. Nevertheless, conventional posts may increase the potential for root fracture.Purpose. This study compared the resistance to vertical root fracture of extracted teeth treated with postcore systems that were modified with polyethylene woven fibers (Ribbond) with those treated with conventional post-and-core systems.Material and methods. Canal instrumentation was performed for 60 maxillary central incisors, and complete crown preparations were made. The coronal portion of each tooth was amputated, and 6 post-and- core systems were studied. Specimens were mounted in acrylic resin blocks with a layer of polyvinyl siloxane covering the roots. Loads were applied at an angle of 130 degrees and measured with a universal testing machine. Results were analyzed statistically with 1-way analysis of variance with Student-Newman-Keuls grouping and chi-square analysis.Results. Cast posts and cores resulted in significantly higher failure thresholds than all others, except for prefabricated, comparably sized, parallel-sided posts with composite cores. All failures in the group with fast posts involved fracture of the teeth, whereas 70% of the teeth with comparably sized parallel-sided posts and composite cores failed as a result of tooth fractures and 30% experienced core fractures. The woven fiber post-core system was significantly lower in strength than all others, and exhibited significantly fewer vertical root fractures.Conclusions. Polyethylene woven fiber and composite resin without a prefabricated post resulted in significantly fea er vertical root fractures, but mean failure load was the lowest. Smaller diameter prefabricated posts combined with the polyethylene woven fiber and composite cores improved resistance to failure. Traditional cast posts and cores were the strongest of the 6 post-core systems.