Hasanzade Mahya, Koulivand Soudabeh, Moslemian Naeime, Alikhasi Marzieh
Dental Research Center, Dentistry Research Institute, Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
Department of Prosthodontics, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
J Adv Prosthodont. 2020 Jun;12(3):173-180. doi: 10.4047/jap.2020.12.3.173. Epub 2020 Jun 18.
This study compared digital (reference point matching) and replica methods for measuring marginal and internal fit of full coverage restorations.
A maxillary left first molar typodent was fixed on to an aluminum base and prepared to receive all-ceramic full coverage restoration. The model was scanned with an intraoral scanner (CEREC Omnicam, Sirona, York, PA, USA). Twelve crowns were fabricated from lithium disilicate blocks (IPS emax CAD, Ivoclar Vivadent) and then crystalized. Marginal and internal fit of each restoration was measured by two examiners using replica and a new digital three-dimensional technique. Reliability between the two methods and two examiners was assessed by correlation and Cronbach's Alpha coefficient (<.05). A Bland-Altman assessment for agreement was used to compare the two methods.
Bland-Altman assessment showed that the mean of difference for marginal, absolute marginal, and axial gap was respectively -1.04 µm, -41.9 µm, and -29.53 µm with limit of agreement (LOA) between -37.26 to 35.18 µm for marginal, -105.85 to 22.05 µm for absolute marginal and -80.52 to 22.02 µm for axial gap. Positive correlation for repeatability (<.05) in determining marginal and internal gaps by the two examiners in both techniques was revealed. Reliability of both techniques in all sites of measurements was at least good (0.8 ≤ α < 0.9).
Both measuring techniques appeared highly reliable for evaluating fit of fixed dental restorations, while reference point matching provided higher values in axial and absolute marginal gap assessment.
本研究比较了数字法（参考点匹配）和复制法在测量全冠修复体边缘适合性和内部适合性方面的差异。
将一个上颌左侧第一磨牙牙模固定在铝制底座上，并预备进行全瓷全冠修复。使用口腔内扫描仪（CEREC Omnicam，德国西诺德公司，宾夕法尼亚州约克）对模型进行扫描。用二硅酸锂块（IPS e.max CAD，义获嘉伟瓦登特公司）制作12个全冠，然后进行结晶处理。由两名检查者分别使用复制法和一种新的数字三维技术测量每个修复体的边缘适合性和内部适合性。通过相关性分析和Cronbach's Alpha系数（<.05）评估两种方法以及两名检查者之间的可靠性。采用Bland-Altman一致性分析来比较这两种方法。
Bland-Altman分析显示，边缘、绝对边缘和轴向间隙差异的平均值分别为-1.04 µm、-41.9 µm和-29.53 µm，边缘适合性的一致性界限（LOA）为-37.26至35.18 µm，绝对边缘适合性为-105.85至22.05 µm，轴向间隙为-80.52至22.02 µm。两种技术中，两名检查者在确定边缘和内部间隙时的重复性均呈正相关（<.05）。两种技术在所有测量部位的可靠性至少为良好（0.8≤α<0.9）。
两种测量技术在评估固定义齿修复体的适合性方面均表现出高度可靠性，而参考点匹配在轴向和绝对边缘间隙评估中提供了更高的值。
