Objectives

CAD/CAM ceramic occlusal veneers are increasingly used as therapeutic options. However, little is known about their mechanical behavior under stress, as the response of the prepared tooth that supports it. The aim of this article is to use for the first time 3D color holography to evaluate the behavior of a molar occlusal veneer under stress and the response of the prepared tooth.

Methods

The occlusal surface of a lower molar is prepared to receive a specific monolithic ceramic reconstruction manufactured with a chairside CAD/CAM system. Longitudinally cut samples are used to get a planar object observation and to “look inside” the tooth. A digital holographic set-up permits to obtain the contact-less and one-shot measurement of the three-dimensional displacement field at the surface of the tooth sample; stain fields are evaluated with low noise-sensitive computation.

Results

Figures show the strain fields with micro-strain units and highlight the behavior of the ROI (region of interest) in the three directions of space. The ROI are: the ceramic, the glue junction, the dentin enamel junction, dentin and enamel. The results show an excellent behavior of the restored tooth without areas of excessive stress concentrations, but also a significant involvement of the dentin enamel junction.

Significance

The ceramic occlusal veneer seems to behave in accordance with the biomechanical concepts ensuring the longevity of the reconstituted tooth. 3D holography is a highly recommended method for studying dental biomechanics.

中文翻译：

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数字彩色全息技术评估CAD / CAM咬合陶瓷重建的力学行为

目标

CAD / CAM陶瓷咬合贴面越来越多地用作治疗选择。然而，人们对它们在应力下的机械性能知之甚少，因为它是支撑它的准备好的牙齿的响应。本文的目的是首次使用3D彩色全息照相技术来评估磨牙咬合贴面在应力作用下的行为以及准备好的牙齿的响应。

方法

准备较低的臼齿的咬合面，以接受使用椅旁CAD / CAM系统制造的特定整体式陶瓷重建体。纵向切割的样品用于观察平面物体并“看向牙齿内部”。数字全息设置允许获得牙齿样本表面三维位移场的非接触式和单次测量。染色场通过低噪声敏感计算进行评估。

结果

图中显示了具有微应变单位的应变场，并突出显示了在三个空间方向上ROI（感兴趣区域）的行为。投资回报率是：陶瓷，胶结，牙本质珐琅结，牙本质和牙釉质。结果表明，修复后的牙齿具有良好的性能，没有过度应力集中的区域，但牙本质釉质连接处也有明显的参与。

意义

陶瓷咬合贴面似乎符合确保再生牙齿寿命的生物力学概念。3D全息术是研究牙科生物力学的强烈推荐方法。