Division of Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, OH 43210-1267, USA.
Clin Implant Dent Relat Res. 2013 Apr;15(2):271-82. doi: 10.1111/j.1708-8208.2011.00411.x. Epub 2011 Dec 15.
This study aimed to measure and compare strains generated by splinted implant crowns retained by cement or screws for two implants with applied load.
A stereolithic resin model was printed using computed tomography data from a patient missing all mandibular molar teeth. Two 4 × 6 mm implants were consecutively placed in the left side. One set of splinted cement and screw-retained crowns were made to fit the two implants. Image correlation technique was used for full-field measurement of strains using an image correlation software and two synchronized high-resolution digital cameras. A random dot pattern was applied to the model surface. Cameras recorded changes in random dot patterns as prostheses were loaded up to 400 N in vertical and oblique directions using a universal testing machine. Testing was repeated three times for cement and screw-retained prostheses. An image correlation algorithm used the dot pattern to define correlation areas or virtual strain gauge boxes. Three-dimensional coordinates of gauge box centers were determined for each recorded photograph and used to calculate strains. Strain distribution data were compared for major, minor, and von Mises strains for each loading condition, as well as peak and average strains for the field of view using an analysis of variance (α = 0.05).
Patterns and magnitudes of strain for cement- and screw-retained splinted crowns were similar under vertical loading. Neither peak nor mean strains were significantly different for the two retention methods. For oblique loading, peak strains were lower for the screw-retained crowns; however, there were no statistically significant differences between the two groups when strains were averaged throughout the entire field of view.
Cement retention did not improve the magnitude of transferred strains for splinted implant crowns using either loading condition.
本研究旨在测量和比较两种种植体应用负荷下，通过粘结或螺丝固位的修复体所产生的应变。
使用从一位缺失所有下颌磨牙的患者的计算机断层扫描数据打印出立体树脂模型。连续在左侧植入两颗 4×6mm 种植体。制作了一套粘结固位螺丝和螺丝固位冠以适应两颗种植体。使用图像相关软件和两个同步的高分辨率数字相机，通过图像相关技术对模型表面的全场应变进行测量。在模型表面应用随机点图案。当使用万能试验机在垂直和倾斜方向上加载至 400N 时，相机记录了随机点图案的变化。对粘结固位和螺丝固位修复体重复测试了三次。图像相关算法使用点图案定义相关区域或虚拟应变计盒。为每个记录的照片确定应变计盒中心的三维坐标，并用于计算应变。使用方差分析（α=0.05）比较了每种加载条件下主要、次要和 von Mises 应变以及整个视场的峰值和平均应变的分布数据。
在垂直加载下，粘结固位和螺丝固位的夹板冠的应变模式和大小相似。两种固位方法的峰值和平均应变均无显著差异。对于倾斜加载，螺丝固位冠的峰值应变较低；然而，当在整个视场平均应变时，两组之间没有统计学上的显著差异。
在两种加载条件下，粘结固位均未改善夹板种植体修复体的传递应变幅度。
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