Rokhshad Rata, Mazaheri Tehrani Azita, Zarbakhsh Arash, Revilla-León Marta
Researcher, Topic Group Dental Diagnostics and Digital Dentistry, ITU/WHO Focus Group AI on Health, Berlin, Germany; and Researcher, Department of Medicine, Section of Endocrinology, Boston University Medical Center, Boston, Mass.
Assistant Professor, Prosthodontics Department, Faculty of Dentistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
J Prosthet Dent. 2025 Mar;133(3):724-735. doi: 10.1016/j.prosdent.2023.04.004. Epub 2023 Jul 18.
Removable partial dentures (RPDs) can be fabricated with conventional casting procedures or computer-aided design and computer-aided manufacturing (CAD-CAM) technologies; however, the manufacturing accuracy and internal discrepancy differences among these manufacturing methods remain uncertain.
The purpose of this systematic review and meta-analysis was to assess the influence of the fabricating method (casting, milling, or additive manufacturing) on the accuracy and internal discrepancy of RPDs.
An electronic search of the literature was performed in 6 databases: PubMed/Medline, Embase, Web of Science, Scopus, Cochrane, and Google Scholar. The studies that assessed the accuracy and internal discrepancy of RPDs fabricated from casting, milling, and additive manufacturing were included. Studies reporting gaps (mean) and standard deviations were included in the meta-analysis. Publication bias was identified using funnel plot asymmetry and the Egger test.
A total of 25 articles were included. The internal discrepancy of the additively manufactured RPDs ranged from 14.4 to 511 μm and from 7 to 419 μm in conventionally fabricated RPDs. For the milling method, 20 to 66 μm horizontal and 17 to 59 μm vertical discrepancies were reported. The Egger tests indicated no publication bias among the studies that were included in the meta-analysis. Four included studies resulted in more than the acceptable clinical gap (311 μm) for the CAD-CAM method. Independently of the manufacturing method, the greatest internal discrepancies reported were observed under the major connectors. RPDs fabricated by using CAD-CAM techniques required fewer clinical appointments, the RPD design was easier to reproduce, and laboratory time was less than with conventional procedures. However, the reviewed studies described several disadvantages, including limited RPD design programs, difficulties in defining the occlusal plane, expensive materials, and increased laboratory cost.
Additive and subtractive technologies provide accurate methods for RPD fabrication; however, all challenges, including limited design software programs have not yet been overcome, and casting is still needed when the framework pattern is milled or printed.
可摘局部义齿（RPD）可以通过传统铸造工艺或计算机辅助设计与计算机辅助制造（CAD-CAM）技术制作；然而，这些制造方法之间的制造精度和内部差异仍不确定。
本系统评价和荟萃分析的目的是评估制造方法（铸造、铣削或增材制造）对RPD精度和内部差异的影响。
在6个数据库中进行文献电子检索：PubMed/Medline、Embase、Web of Science、Scopus、Cochrane和谷歌学术。纳入评估通过铸造、铣削和增材制造制作的RPD的精度和内部差异的研究。报告间隙（均值）和标准差的研究纳入荟萃分析。使用漏斗图不对称性和Egger检验识别发表偏倚。
共纳入25篇文章。增材制造的RPD的内部差异范围为14.4至511μm，传统制作的RPD的内部差异范围为7至419μm。对于铣削方法，报告的水平差异为20至66μm，垂直差异为17至59μm。Egger检验表明纳入荟萃分析的研究之间无发表偏倚。4项纳入研究中CAD-CAM方法的临床间隙超过可接受范围（311μm）。无论制造方法如何，报告的最大内部差异出现在大连接体下方。使用CAD-CAM技术制作的RPD所需的临床就诊次数更少，RPD设计更容易复制，且实验室时间比传统方法少。然而，综述的研究描述了几个缺点，包括RPD设计程序有限、确定咬合平面困难、材料昂贵以及实验室成本增加。
增材和减材技术为RPD制作提供了精确方法；然而，包括设计软件程序有限在内的所有挑战尚未克服，当框架模型进行铣削或打印时仍需要铸造。
