Maccari Paulo César, Cosme Dúcia Caldas, Oshima Hugo Mitsuo, Burnett Luiz Henrique, Shinkai Rosemary Sadami
Department of Prosthodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
J Esthet Restor Dent. 2007;19(1):30-6; discussion 37. doi: 10.1111/j.1708-8240.2006.00060.x.
Many post systems are available to clinicians, yet no consensus exists about which one is better in restoring endodontically treated teeth.
This study evaluated the fracture strength of teeth with flared canals and restored with two fiber-reinforced resin systems (glass fiber: FRC Postec [Ivoclar Vivadent, Schaan, Liechtenstein]; quartz fiber: D.T. Light-Post [Bisco Dental Products, Schaumburg, IL, USA]), and one custom cast base metal (Ni-Cr) post and core system.
Thirty anterior teeth had their crowns removed below the cemento-enamel junction and were endodontically treated. The canals were prepared for post fixation, and the canal walls were flared using a taper diamond bur. The prepared roots were randomly divided into three groups according to the post system. All posts were cemented with an adhesive resin cement. For the fiber-reinforced resin posts, cores were built up using microhybrid composite. Metallic crowns were luted using zinc phosphate cement. Specimens were loaded at 45 degrees in a universal testing machine at a crosshead speed of 0.5 mm/min until failure. The mode of failure was classified as repairable or nonrepairable.
Teeth restored with cast posts had fracture strength twice that of teeth restored with resin posts. Fiber-reinforced resin posts failed at a compressive force comparable to clinical conditions, but all failures were repairable.
Fracture strength and mode of failure in anterior teeth with flared canals varied according to the type of post used to support a crown.
Under the conditions of this study, cast posts are preferable to restore endodontically treated teeth with flared canals and no ferrule.
临床医生可使用多种桩核系统，但对于哪种系统在修复根管治疗后的牙齿方面更优尚无共识。
本研究评估了使用两种纤维增强树脂系统（玻璃纤维：FRC Postec[义获嘉伟瓦登特公司，列支敦士登沙恩]；石英纤维：D.T. Light-Post[美国伊利诺伊州绍姆堡的必思科牙科产品公司]）以及一种定制铸造的贱金属（镍铬）桩核系统修复的扩管牙齿的抗折强度。
30颗前牙在牙骨质-釉质界下方截冠并进行根管治疗。预备根管以固定桩，使用锥形金刚砂车针扩管。根据桩核系统将预备好的牙根随机分为三组。所有桩均用粘结性树脂水门汀粘结。对于纤维增强树脂桩，使用微混合复合材料构建核。使用磷酸锌水门汀粘结金属冠。在万能试验机上以45度角加载试样，横梁速度为0.5 mm/min直至破坏。将破坏模式分为可修复或不可修复。
铸造桩修复的牙齿的抗折强度是树脂桩修复牙齿的两倍。纤维增强树脂桩在与临床情况相当的压缩力下发生破坏，但所有破坏均为可修复的。
扩管前牙的抗折强度和破坏模式因用于支持冠的桩的类型而异。
在本研究条件下，铸造桩更适合修复根管治疗后的扩管且无箍的牙齿。
