Borges Alexandre Luiz Souto, Costa Anna Karina Figueiredo, Dal Piva Amanda Maria de Oliveira, Pinto Alana Barbosa Alves, Tribst João Paulo Mendes
Department of Dental Materials and Prosthodontics, São Paulo State University, Institute of Science and Technology, Brazil.
J Dent Res Dent Clin Dent Prospects. 2021 Summer;15(3):188-196. doi: 10.34172/joddd.2021.032. Epub 2021 Aug 25.
The present study aimed to evaluate the influence of the veneering technique on the tensile stress distribution and survival of full-ceramic fixed dental prostheses (FDPs). A three-dimensional model of an FDP was modeled on a second premolar and a second molar with a pontic between them for finite element analysis (FEA). The groups were divided according to the veneering technique: conventional stratification, rapid layer, and CAD-on techniques. A mesh control test determined the number of elements and nodes. The materials' properties were attributed to each solid component with isotropic, homogeneous, and linear elastic behavior. For the in vitro fatigue test (n=30), the FDPs were cemented on dentin analog abutments and submitted to 2×10 mechanical cycles (100 N at 3 Hz). Maximum principal stress showed that the connector between the pontic and the second molar concentrated higher stresses, regardless of the techniques: Rapid layer (6 MPa) > CAD-on (5.5 MPa) > conventional stratification (4 MPa). The conventional stratification technique concentrated high stresses at the interface between the framework and veneering ceramic (2 MPa), followed by the rapid layer (1.8 MPa) and CAD-on (1.5 MPa) techniques. The crowns fabricated using the rapid layer and CAD-on techniques exhibited a 100% survival rate, while the conventional stratification group had 0% survival. Even with similar stress distribution between the veneering techniques, the conventional stratification technique was more prone to failure under fatigue due to higher defects incorporated than CAD-on and rapid layer techniques.
本研究旨在评估饰面技术对全瓷固定义齿（FDPs）拉伸应力分布和存活率的影响。在第二前磨牙和第二磨牙上建立了一个带有桥体的FDP三维模型，用于有限元分析（FEA）。根据饰面技术将分组：传统分层法、快速分层法和CAD-on技术。通过网格控制测试确定单元和节点数量。材料属性赋予各具有各向同性、均匀和线弹性行为的固体部件。对于体外疲劳试验（n = 30），将FDP粘结在牙本质模拟基台上，并施加2×10次机械循环（3Hz下100N）。最大主应力表明，无论采用何种技术，桥体与第二磨牙之间的连接部位应力集中较高：快速分层法（6MPa）> CAD-on技术（5.5MPa）>传统分层法（4MPa）。传统分层技术在支架与饰面陶瓷之间的界面处集中了较高应力（2MPa），其次是快速分层法（1.8MPa）和CAD-on技术（1.5MPa）。采用快速分层法和CAD-on技术制作的冠存活率为100%，而传统分层组的存活率为0%。即使饰面技术之间的应力分布相似，但由于传统分层技术比CAD-on技术和快速分层技术掺入的缺陷更多，因此在疲劳情况下更容易失效。
