Rutkunas Vygandas, Kules Daniel, Mischitz Ingrida, Huber Sandra, Revilla-León Marta, Larsson Christel, Janda Martin
Professor, Department of Prosthodontics, Institute of Odontology, Faculty of Medicine, Vilnius University, Vilnius, Lithuania; and Director, Digitorum Research Center, Vilnius, Lithuania.
Postgraduate student, Department of Periodontology, Faculty of Medicine, Vilnius University, Vilnius, Lithuania; and Researcher, Digitorum Research Center, Vilnius, Lithuania.
J Prosthet Dent. 2025 Jan;133(1):222-228. doi: 10.1016/j.prosdent.2024.01.014. Epub 2024 Feb 27.
The fit of implant-supported prostheses plays an important role in their mechanical and biological stability. Clinically, the prosthetic fit is typically assessed radiographically, but this method relies on the operator's subjective evaluation. Whether available digital tools could optimize the evaluation of the prosthetic fit is uncertain.
The purpose of this in vitro study was to evaluate the influence of an image processing program on the radiographic detection of discrepancies in the active and passive fit of implant-supported prostheses. Two-implant-supported screw-retained prostheses were analyzed by simulating the vertical and horizontal misfits of 3 different implant abutment configurations.
Seven casts were fabricated using 2 internal-connection titanium implants: 1 control; 3 with vertical (V) misfit of 50 µm, 100 µm, 150 µm; and 3 with horizontal (H) misfit of 35 µm, 70 µm, 100 µm. Thirty bar-shaped zirconia frameworks were fabricated and divided into 3 groups (n=10) according to their attachment to 2 engaging (E-E), 2 nonengaging (NE-NE), and engaging and nonengaging (E-NE) titanium bases. Digital parallel periapical radiographs were made of each specimen in the passive and active fit situation on each cast (1-screw test), except for the E-E specimens, which were only seated on the control, H35, and H70 casts because the fit on the remaining casts was poor. The mean gray value (MGV) was measured at the chosen regions of interest on the second implant (side B) using the ImageJ software program. Differences in the MGV measurements between the passive and active conditions were tested using a t test (α=.05) and compared the different misfit levels using analysis of variance (1-way ANOVA), followed by the Tukey HSD test (α=.05).
The highest values for the differences between passive and active fit were found for the V150 and H100 misfit simulations (P<.05). Statistical differences between the MGVs were found with some exceptions: the smallest simulated misfits (H35 and V50) revealed statistically significant MGV differences from the highest simulated misfits (V150, H100) and from the H70 in the groups where an engaging component was present (P>.05). In the horizontal misfit group of NE-NE abutment configuration, H70 revealed no significant difference from the control group cast (P>.05).
Measuring MGV differences between passive and active fit could be a promising alternative for detecting 70- to 150-µm gaps in the implant-abutment connection that result from the misfit. However, the procedure was not adequate for detecting <50 µm gaps, cannot be uniformly applied to all types of implant-abutment connections, and requires 2 exposures to X-radiation.
种植体支持的修复体的适配性在其机械和生物学稳定性方面起着重要作用。临床上，修复体适配性通常通过影像学进行评估，但这种方法依赖于操作者的主观评价。现有的数字工具能否优化修复体适配性评估尚不确定。
本体外研究的目的是评估图像处理程序对种植体支持的修复体主动和被动适配性差异的影像学检测的影响。通过模拟3种不同种植体基台配置的垂直和水平不匹配，对两颗种植体支持的螺丝固位修复体进行分析。
使用两颗内连接式钛种植体制作7个模型：1个对照；3个垂直（V）不匹配分别为50 µm、100 µm、150 µm；3个水平（H）不匹配分别为35 µm、70 µm、100 µm。制作30个棒状氧化锆框架，并根据其与2个啮合（E-E）、2个非啮合（NE-NE）以及啮合和非啮合（E-NE）钛基台的连接方式分为3组（n = 10）。除了E-E标本仅就位在对照、H35和H70模型上（因为在其余模型上的适配性较差），对每个模型上的每个标本在被动和主动适配情况下进行数字平行根尖片拍摄（单螺丝试验）。使用ImageJ软件程序在第二颗种植体（B侧）的选定感兴趣区域测量平均灰度值（MGV）。使用t检验（α = .05）测试被动和主动状态下MGV测量值的差异，并使用方差分析（单因素方差分析）比较不同不匹配水平，随后进行Tukey HSD检验（α = .05）。
在V150和H100不匹配模拟中，被动和主动适配之间的差异值最高（P < .05）。发现MGV之间存在统计学差异，但有一些例外：最小的模拟不匹配（H35和V50）与最高的模拟不匹配（V150、H1）以及存在啮合部件的组中的H70相比，显示出统计学上显著的MGV差异（P > .05）。在NE-NE基台配置的水平不匹配组中，H70与对照组模型相比无显著差异（P > .05）。
测量被动和主动适配之间的MGV差异可能是检测种植体 - 基台连接中因不匹配导致的70至150 µm间隙的一种有前景的替代方法。然而，该方法不足以检测小于50 µm的间隙，不能统一应用于所有类型的种植体 - 基台连接，并且需要两次X线照射。
