University of Amsterdam School of Dentistry, ACTA, The Netherlands.
Int J Oral Maxillofac Implants. 2011 Nov-Dec;26(6):1344-50.
Despite the development of novel and more precise fabrication methods, absolute passive fit of implant-supported superstructures has yet to be consistently achieved. In the past, several laboratory techniques have been described to analyze fit. The purpose of this study was to assess two methods of fit evaluation with a control (well fitting) prosthesis and an intentionally misfit prosthesis.
In this in vitro study, two comparable implant-supported superstructures (control and test misfit) were fabricated after scanning a test cast of a maxilla with four implants (two on each side). The test structure was fabricated with a known minor misfit on one of the inserted implants by manipulating the coordinates on the scanned files. The control superstructure was fabricated as accurately as possible without manipulating any scanned information. Both superstructures were evaluated using optical scanning and strain gauge measurements by an investigator who was blinded to the designed misfit.
Optical scanning demonstrated an accuracy of 10 μm for the control frame, while the misfit frame demonstrated greater discrepancies, both at the intentionally misfit connection (connection #2, misfit of 29 μm) and at the other connections (#1, 4 μm; #3, 5 μm; #4, 4 μm), although the latter connections showed less misfit. The strain gauge measurement showed a higher mean deviation of 26.2 μm (± 5.9 μm) in the test model, versus 15.3 μm (± 4.3 μm) in the control model.
Optical scan analysis was able to detect the misfit in the test superstructure and the manipulated implant. The strain gauge measurements confirmed these findings, indicating that both methods of assessing inaccuracy are effective. Optical scan analysis may be used as a simplified and clinically applicable method to detect minor misfits in implant-supported superstructures.
尽管已经开发出了新型且更精确的制造方法，但仍然未能始终如一地实现种植体支持的上部结构的绝对被动适配。过去，已经描述了几种用于分析配合度的实验室技术。本研究的目的是评估两种配合度评估方法，使用一个（拟合良好的）对照修复体和一个故意不匹配的修复体。
在这项体外研究中，在扫描带有四个种植体（每侧两个）的上颌模型的测试模型后，制造了两个类似的种植体支持的上部结构（对照和测试不匹配）。通过操纵扫描文件上的坐标，制造了测试结构，使其在一个插入的种植体上具有已知的轻微不匹配。对照上部结构尽可能准确地制造，而不操纵任何扫描信息。由一位对设计不匹配不知情的研究人员使用光学扫描和应变计测量来评估两个上部结构。
光学扫描显示，对照框架的精度为 10μm，而不匹配框架显示出更大的差异，无论是在故意不匹配的连接（连接#2，不匹配为 29μm）还是在其他连接（#1，4μm；#3，5μm；#4，4μm），尽管后一种连接的不匹配较小。应变计测量显示，在测试模型中平均偏差为 26.2μm（±5.9μm），而在对照模型中为 15.3μm（±4.3μm）。
光学扫描分析能够检测到测试上部结构和操纵种植体中的不匹配。应变计测量证实了这些发现，表明这两种评估不准确的方法都是有效的。光学扫描分析可作为一种简化且适用于临床的方法，用于检测种植体支持的上部结构中的轻微不匹配。
