Department of Prosthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
, 57-59 Kolokotroni Str., Piraeus, Greece.
Int J Implant Dent. 2021 Feb 15;7(1):12. doi: 10.1186/s40729-021-00290-6.
The replica technique with its modifications (negative replica) has been used for the assessment of marginal fit (MF). However, identification of the boundaries between prosthesis, cement, and abutment is challenging. The recently developed Digital Image Analysis Sequence (DIAS) addresses this limitation. Although DIAS is applicable, its reliability has not yet been proven. The purpose of this study was to verify the DIAS as an acceptable method for the quantitative assessment of MF at cemented crowns, by conducting statistical tests of agreement between different examiners.
One hundred fifty-one implant-supported experimental crowns were cemented. Equal negative replicas were produced from the assemblies. Each replica was sectioned in six parts, which were photographed under an optical microscope. From the 906 standardized digital photomicrographs (0.65 μm/pixel), 130 were randomly selected for analysis. DIAS included tracing the profile of the crown and the abutment and marking the margin definition points before cementation. Next, the traced and marked outlines were superimposed on each digital image, highlighting the components' boundaries and enabling MF measurements. One researcher ran the analysis twice and three others once, independently. Five groups of 130 measurements were formed. Intra- and interobserver reliability was evaluated with intraclass correlation coefficient (ICC). Agreement was estimated with the standard error of measurement (SEM), the smallest detectable change at the 95% confidence level (SDC), and the Bland and Altman method of limits of agreement (LoA).
Measured MF ranged between 22.83 and 286.58 pixels. Both the intra- and interobserver reliability were excellent, ICC = 1 at 95% confidence level. The intra- and interobserver SEM and SDC were less than 1 and 3 pixels, respectively. The Bland-Altman analysis presented graphically high level of agreement between the mean measurement of the first observer and each of the three other observers' measurements. Differences between observers were normally distributed. In all three cases, the mean difference was less than 1 pixel and within ± 3 pixels LoA laid at least 95% of differences. T tests of the differences did not reveal any fixed bias (P > .05, not significant).
The DIAS is an objective and reliable method able to detect and quantify MF at ranges observed in clinical practice.
复制技术及其修改（负复制）已被用于评估边缘适合性（MF）。然而，识别修复体、粘结剂和基台之间的边界具有挑战性。最近开发的数字图像分析序列（DIAS）解决了这一限制。尽管 DIAS 是适用的，但它的可靠性尚未得到证实。本研究的目的是通过对不同检查者之间的一致性进行统计检验，验证 DIAS 作为一种可接受的方法，用于定量评估粘结冠的 MF。
制作了 151 个种植体支持的实验性牙冠，并从组件中制作了相同的负复制品。将每个复制品分成六部分，在光学显微镜下拍摄。从 906 张标准化的数字显微照片（0.65μm/pixel）中，随机选择 130 张进行分析。DIAS 包括在粘结前，对牙冠和基台的轮廓进行追踪，并标记边缘定义点。然后，将追踪和标记的轮廓叠加在每个数字图像上，突出显示组件的边界，并能够进行 MF 测量。一位研究人员进行了两次分析，另外三位研究人员各进行了一次分析。共形成了 5 组 130 次测量。采用组内相关系数（ICC）评估观察者内和观察者间的可靠性。通过测量误差（SEM）、95%置信水平下最小可检测变化（SDC）和 Bland 和 Altman 法的界限（LoA）来估计一致性。
测量的 MF 范围为 22.83 到 286.58 像素。观察者内和观察者间的可靠性均为优秀，ICC=1，置信水平为 95%。观察者内和观察者间的 SEM 和 SDC 均小于 1 和 3 像素。Bland-Altman 分析以图形方式显示了第一位观察者的平均测量值与其他三位观察者的测量值之间的高度一致性。观察者之间的差异呈正态分布。在所有三种情况下，平均差异小于 1 像素，且至少有 95%的差异落在 ±3 像素的 LoA 内。差异的 t 检验未显示任何固定偏差（P＞.05，无统计学意义）。
DIAS 是一种客观可靠的方法，能够检测和量化临床实践中观察到的 MF 范围。
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