Zarone Fernando, Apicella Davide, Sorrentino Roberto, Ferro Valeria, Aversa Raffaella, Apicella Antonio
Dipartimento di Scienze Odontostomatologiche e Maxillo-Facciali, Università degli Studi di Napoli Federico II, Italy.
Dent Mater. 2005 Dec;21(12):1178-88. doi: 10.1016/j.dental.2005.02.014. Epub 2005 Aug 10.
The present study aimed at providing 3D-FEA engineering tools for the understanding of the influence of tooth preparation design on the stress distribution and localization of critical sites in maxillary central incisors restored by means of alumina porcelain veneers under functional loading.
A 3D-FEM model of a maxillary central incisor is presented. An arbitrary chewing static force of 10 N was applied with an angulation of 60 and 125 degrees to the tooth longitudinal axis at the palatal surface of the crown. The model was considered to be restored by means of alumina porcelain veneers with different tooth preparation designs. The differences in occlusal load transfer ability of the two restorative systems are discussed.
The maximum Von Mises equivalent stress values were observed in the window restorative system for both 125 and 60 degrees load angulations. When the chamfer with palatal overlap preparation was simulated, the stress distributed uniformly in the cement layer, whereas in the window preparation the stress mainly occurred in the incisal area of the cement layer.
When restoring a tooth by means of porcelain veneers, the chamfer with palatal overlap preparation better restores the natural stress distribution under load than the window technique.
本研究旨在提供三维有限元分析工程工具，以了解在功能载荷下，牙体预备设计对采用氧化铝瓷贴面修复的上颌中切牙关键部位应力分布和定位的影响。
建立了上颌中切牙的三维有限元模型。在牙冠腭面，以60度和125度的角度向牙长轴施加10 N的任意咀嚼静力。该模型被认为采用了不同牙体预备设计的氧化铝瓷贴面进行修复。讨论了两种修复系统在咬合负荷传递能力上的差异。
在125度和60度负荷角度下，均在开窗式修复系统中观察到最大的冯·米塞斯等效应力值。当模拟带有腭侧重叠的肩台预备时，应力在粘结层中均匀分布，而在开窗式预备中，应力主要出现在粘结层的切端区域。
采用瓷贴面修复牙齿时，带有腭侧重叠的肩台预备比开窗技术能更好地恢复负荷下的自然应力分布。
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