Tribst João Paulo Mendes, Dal Piva Amanda Maria de Oliveira, de Jager Niek, Bottino Marco Antonio, de Kok Paul, Kleverlaan Cornelis Johannes
Department of Dental Materials and Prosthetics, São Paulo State University (UNESP), Institute of Science and Technology, São José dos Campos, Brazil.
Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, The Netherlands.
J Prosthodont. 2021 Apr;30(4):335-344. doi: 10.1111/jopr.13244. Epub 2020 Sep 10.
To assess stress distribution in full-crowns with a composite buildup and endocrowns under axial or oblique loads, both with different ferrules (1 or 2 mm) and ceramic materials (glass ceramic or hybrid ceramic).
Sixteen models were analyzed with finite element analysis. No-separation contacts were considered between restoration/resin cement and resin cement/tooth. The contact between the fixation cylinder and the root was considered perfectly bonded. The axial load was applied to the occlusal surface and the oblique load was applied to the buccal cusp. The resulting tensile stresses were shown for the crown, the cement layer and the tooth.
Almost all factors influenced the stress distribution significantly in the crown and the cement layer, as well as the tooth. The only exception was found under oblique loading by the restoration material and the type of crown that were of no significant influence on the stress distribution in the tooth.
Under axial load, the endocrown showed the least tensile stresses in the tooth, but under oblique loads, the full-crown showed less tensile stresses than the endocrown. With the hybrid ceramic material, lower stresses were found in the crown, but higher stresses were present in the cement layer. The 2 mm ferrule is beneficial for reducing the resulting tensile stresses in all modalities.
评估采用复合树脂堆塑的全冠和内冠在轴向或斜向载荷下的应力分布，两者均采用不同的边缘（1或2毫米）和陶瓷材料（玻璃陶瓷或混合陶瓷）。
采用有限元分析对16个模型进行分析。修复体/树脂水门汀以及树脂水门汀/牙齿之间考虑为无分离接触。固定柱与牙根之间的接触视为完全粘结。轴向载荷施加于咬合面，斜向载荷施加于颊尖。给出了牙冠、水门汀层和牙齿的拉应力结果。
几乎所有因素对牙冠、水门汀层以及牙齿中的应力分布均有显著影响。唯一的例外是在斜向载荷下，修复材料和牙冠类型对牙齿中的应力分布无显著影响。
在轴向载荷下，内冠在牙齿中显示出最小的拉应力，但在斜向载荷下，全冠显示出比内冠更小的拉应力。使用混合陶瓷材料时，牙冠中的应力较低，但水门汀层中的应力较高。2毫米的边缘有利于降低所有形式下产生的拉应力。
