Department of Oral and Maxillofacial Rehabilitation, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.
J Prosthodont. 2012 Aug;21(6):440-50. doi: 10.1111/j.1532-849X.2012.00860.x. Epub 2012 Jun 1.
This study compares the stress distribution in the structure of a loaded endodontically treated maxillary extracted canine restored with either custom-made zirconia (Cercon) or cast gold dowel and core.
Standard treatments were implemented to prepare the gutta-percha-filled root canal and dowel space. The tooth along with the dowel and core fabricated pattern resin were prepared to receive an all-ceramic (Cercon) crown. An impression was made for the tooth preparation with the zirconia milled dowel and core in place to fabricate the Cercon crown using CAD/CAM. The restored canine was scanned, and from the scan two models were constructed with the surrounding ligament and bone. Three-dimensional finite element elastic analysis was then carried out for the stress distribution within the different regions of the two models due to a concentrated force of 100 N applied at the mid-lingual area. Analyses were made for three load angulations, vertical, buccolingual horizontal, and an in-between oblique force at 45(o) . Each region of the models was assumed isotropic and homogeneous. The two restored canines with zirconia and gold were compared in terms of the resulting maximum tensile, compressive, and Von Mises stresses.
Generally, there were no significant differences in the maximum stresses in most regions for both models. Von Mises stresses for zirconia dowel and core was 8.966 MPa and for cast gold dowel and core was 8.752 MPa. The maximum tensile stress for zirconia dowel and core was 9.326 MPa, and for cast gold dowel and core was 8.166 MPa.
The present work validates the use of CAD/CAM zirconia material for ceramic dowel and cores.
CAD/CAM Zirconia can be used for a custom-made dowel and core in an esthetically demanding zone as an esthetic replacement for a metal cast dowel and core when restoring endodontically treated teeth.
本研究比较了负载的根管治疗上颌犬牙用定制氧化锆（Cercon）或铸造金嵌体和核修复后的结构中的应力分布。
对充满牙胶的根管和嵌体空间进行了标准处理。将带有嵌体和核的牙以及制造的嵌体树脂图案制备好，以接收全陶瓷（Cercon）冠。用 CAD/CAM 制造 Cercon 冠时，将氧化锆铣制的嵌体和核放在牙预备的印模上进行。扫描修复后的犬牙，从扫描中构建两个模型，包括周围的韧带和骨骼。然后，对两个模型的不同区域内的应力分布进行三维有限元弹性分析，在模型的中舌区域施加 100N 的集中力。分析了垂直、颊舌水平和 45(o) 之间的斜向力三种加载角度。假设模型的每个区域均为各向同性和均匀的。比较了氧化锆和金制成的两个修复犬牙在最大拉伸、压缩和 Von Mises 应力方面的结果。
在两种模型的大多数区域中，最大应力没有显著差异。氧化锆嵌体和核的 Von Mises 应力为 8.966MPa，铸造金嵌体和核的 Von Mises 应力为 8.752MPa。氧化锆嵌体和核的最大拉伸应力为 9.326MPa，铸造金嵌体和核的最大拉伸应力为 8.166MPa。
本工作验证了 CAD/CAM 氧化锆材料在陶瓷嵌体和核中的应用。
CAD/CAM 氧化锆可用于在美学要求高的区域中定制嵌体和核，作为金属铸造嵌体和核的美学替代品，用于修复根管治疗后的牙齿。
