Assistant Professor, Department of General Surgery and Medical-Surgical Specialties, University of Catania School of Dentistry, Catania, Italy.
Graduate student, Department of General Surgery and Medical-Surgical Specialties, School of Dentistry, University of Catania, Catania, Italy.
J Prosthet Dent. 2022 Mar;127(3):425-429. doi: 10.1016/j.prosdent.2020.08.040. Epub 2020 Dec 11.
Different technologies have been used to fabricate trial restorations. However, studies investigating the accuracy of trial restorations fabricated with different techniques in comparison with the initial 3-dimensional virtual design are lacking.
The purpose of this clinical study was to evaluate completely digital workflows for managing the esthetic outcome through the production of trial restorations with 2 different technologies: stereolithography apparatus (SLA 3D) and computer-aided design and computer-aided manufacturing (CAD-CAM). The aim was to determine which of them provided trial restorations more similar to those of the 3D virtual design.
Thirty participants who did not meet ideal esthetic proportions for the anterior maxillary teeth were enrolled. For each, 2 intraoral and extraoral frontal photographs and intraoral digital scans were made. The digital images were processed by using the Digital Smile System (DSS) software program to have a smile preview after the treatment. Virtual designs were matched with the surface tessellation language (STL) files from the intraoral scans and edited by exocad DentalCAD to create custom trial restorations using SLA 3D and CAD-CAM technologies. Two independent examiners measured the virtual restorations by using virtual calipers in the software program and then the trial restorations by using digital calipers. The measurements were carried out from the incisal edge to the gingival margin, mesial-distal widths of the central incisors, and the distance from the distal margins of maxillary right and left canines. The trial restorations were evaluated intraorally for fit. The participants approved the definitive treatment outcome after the evaluation. The normality of data was verified with the Shapiro-Wilk test, and the Friedman test for matched groups with the Bonferroni and Dunn tests for multiple comparisons were used (α=.05).
Comparing the 3D designs with the printed trial restorations, a significant increase was only found in the mesial-distal width of central incisors (P<.05), while the milled trial restorations showed a significant increase (P<.05) of all measurements except for the maxillary right and left canines. Comparing printed trial restorations with the milled ones, the only significant difference was found in height measures of maxillary right central incisor, with the milled trial restorations exhibiting higher values than the printed ones (P<.05). The printed trial restorations showed good clinical fit, and the milled restorations had poor clinical adaptation.
The accuracy of printed trial restorations was higher than that of milled trial restorations, except for the canine to canine width of maxillary anterior teeth. However, this difference did not compromise the fit of the printed trial restorations. The milled trial restorations had increased dimensions in comparison with the measurements made in 3D designs, and consequently, their clinical fit was compromised. SLA 3D- printing technology provided the best fit.
不同的技术已被用于制作试验修复体。然而，缺乏研究比较不同技术制作的试验修复体与初始三维虚拟设计的准确性。
本临床研究的目的是通过使用两种不同技术（立体光固化成型机[SLA 3D]和计算机辅助设计与计算机辅助制造[CAD-CAM]）生产试验修复体，评估完全数字化工作流程在管理美学效果方面的应用。目的是确定哪种技术提供的试验修复体更接近三维虚拟设计。
招募了 30 名不符合上前牙美学比例的患者。每位患者都拍摄了 2 张口内和口外正面照片和口内数字扫描。使用 Digital Smile System（DSS）软件程序对数字图像进行处理，以便在治疗后预览微笑效果。虚拟设计与口内扫描的表面镶嵌语言（STL）文件相匹配，并使用 exocad DentalCAD 编辑，以使用 SLA 3D 和 CAD-CAM 技术创建定制的试验修复体。两名独立的检查者在软件程序中使用虚拟卡尺测量虚拟修复体，然后使用数字卡尺测量试验修复体。测量从切缘到牙龈边缘、中切牙的近远中宽度以及上颌右侧和左侧尖牙的远中边缘距离。在口内评估试验修复体的适合度。评估后，患者对最终治疗效果表示认可。使用 Shapiro-Wilk 检验验证数据的正态性，使用 Friedman 检验对匹配组进行检验，并使用 Bonferroni 和 Dunn 检验进行多重比较（α=.05）。
与 3D 设计相比，仅发现中切牙的近远中宽度有显著增加（P<.05），而铣削试验修复体的所有测量值均有显著增加（P<.05），除上颌右侧和左侧尖牙外。与铣削试验修复体相比，打印试验修复体的唯一显著差异是上颌右侧中切牙的高度测量值，铣削试验修复体的高度值高于打印试验修复体（P<.05）。打印试验修复体具有良好的临床贴合度，而铣削修复体的临床适应性较差。
与铣削试验修复体相比，打印试验修复体的精度更高，除了上颌前牙的尖牙间宽度。然而，这种差异并没有影响打印试验修复体的贴合度。与 3D 设计中的测量值相比，铣削试验修复体的尺寸增加，因此其临床贴合度受到影响。SLA 3D 打印技术提供了最佳的贴合度。
