School of Dentistry-University of Naples Federico II, Italy.
Department of Industrial Engineering, Fraunhofer JL IDEAS-University of Naples Federico II, Italy.
Dent Mater. 2017 Dec;33(12):1456-1465. doi: 10.1016/j.dental.2017.10.010. Epub 2017 Nov 8.
To investigate the influence of specific resin-composite, glass ceramic and glass ionomer cement (GIC) material combinations in a "multi-layer" technique to replace enamel and dentin in class II mesio-occlusal-distal (MOD) dental restorations using 3D-Finite Element Analysis (FEA).
Four 3D-FE models (A-D) of teeth, adhesively restored with different filling materials, were created and analyzed in comparison with a 3D model (E) of a sound lower molar. Models A, B & C had "multilayer" constructions, consisting of three layers: adhesive, dentin replacement and enamel replacement. Model A: had a low modulus (8GPa) composite replacing dentin and a higher modulus (12GPa) composite replacing enamel. Model B: had a GI cement replacing dentin and a higher modulus (12GPa) composite replacing enamel. Model C: had a low modulus (8GPa) composite replacing dentin and a very high modulus (70GPa) inlay replacing enamel. Model D: had a lithium disilicate inlay replacing both dentin and enamel with a luting cement base-layer. Polymerization shrinkage effects were simulated and a load of 600N was applied. All the materials were assumed to behave elastically throughout the entire deformation.
Model A showed the highest stress distribution along all the adhesive interfaces of the shrinking resin-based materials with a critical condition and failure risk marginally and internally. Model D, by contrast, showed a more favorable performance than either of the multilayer groups (A-C). Stress and displacement plots showed an elastic response similar to that obtained for the sound tooth model. Model B and Model C performed according to their bilayer material properties. The use of a non-shrink dentin component simulating a GIC clearly affected the shrinkage stress at the basis of the Model B; while the bulk resin composite having a 12GPa Young's modulus and linear polymerization shrinkage of 1% strongly influenced the biomechanical response in the bucco-lingual direction.
Direct resin-based composite materials applied in multilayer techniques to large class II cavities, with or without shrinking dentin layers, produced adverse FEA stress distributions and displacements. An indirect lithium disilicate inlay used to replace lost dentin and enamel in posterior restored teeth generated lower stress levels, within the limits of the elastic FEA model.
通过三维有限元分析（FEA）研究特定树脂复合材料、玻璃陶瓷和玻璃离子水门汀（GIC）材料组合在“多层”技术中对 II 类近中-颊-远（MOD）牙体缺损修复中替代釉质和牙本质的影响。
创建并分析了四个具有不同填充材料的牙齿的 3D-FE 模型（A-D），并与一个健康的下颌磨牙的 3D 模型（E）进行了比较。模型 A、B 和 C 具有“多层”结构，由三层组成：粘合剂、牙本质替代层和牙釉质替代层。模型 A：使用低模量（8GPa）复合材料替代牙本质，使用高模量（12GPa）复合材料替代牙釉质。模型 B：使用 GI 水门汀替代牙本质，使用高模量（12GPa）复合材料替代牙釉质。模型 C：使用低模量（8GPa）复合材料替代牙本质，使用超高模量（70GPa）嵌体替代牙釉质。模型 D：使用锂硅玻璃陶瓷嵌体替代牙本质和牙釉质，并用粘固剂基底层。模拟聚合收缩效应并施加 600N 的载荷。所有材料在整个变形过程中均被假定为弹性体。
模型 A 在收缩树脂基材料的所有粘合界面上显示出最高的应力分布，具有临界条件和轻微的内部失效风险。相比之下，模型 D 的性能优于任何多层组（A-C）。应力和位移图显示出与健康牙齿模型相似的弹性响应。模型 B 和模型 C 的性能符合其双层材料特性。使用模拟 GIC 的非收缩牙本质成分会明显影响模型 B 的基底收缩应力；而具有 12GPa 杨氏模量和 1%线性聚合收缩率的大块树脂复合材料强烈影响颊舌方向的生物力学响应。
直接使用树脂基复合材料的多层技术应用于具有或不具有收缩牙本质层的大 II 类腔，会产生不良的 FEA 应力分布和位移。在后牙修复中使用间接的锂硅玻璃陶瓷嵌体替代丢失的牙本质和牙釉质会产生较低的应力水平，在弹性 FEA 模型的限制范围内。
