Division of Dentistry, School of Medical Sciences, University of Manchester, UK; Prosthetic Dental Sciences, College of Dentistry, King Saud University, Saudi Arabia.
Prosthetic Dental Sciences, College of Dentistry, King Saud University, Saudi Arabia.
Dent Mater. 2022 Jun;38(6):1072-1081. doi: 10.1016/j.dental.2022.04.025. Epub 2022 May 7.
This study was designed to investigate CAD/CAM restorative blocks and other resin-based materials by (i) determining their chemical composition, (ii) comparing their radiopacity and (iii) correlating their radiopacity with specimen thickness.
Disk specimens, of 1and 2 mm thickness (n = 3), were prepared from five CAD/CAM and six resin-based composites (RBCs). The CAD/CAM resin-composites included aesthetic types: CeraSmart (CS), Grandio Blocs (GB), Lava Ultimate (LU), plus a polymer infiltrated ceramic Vita Enamic (VE), and a feldspathic ceramic Vita Mark II (VM II). The six RBCs were for different clinical applications: direct filling, flowable, bulk fill, base and two luting cements. The specimens were radiographed alongside an aluminium step wedge and a tooth section. Digital images were analysed, and the radiopacity of each specimen was determined according to ISO 1311/2014. Statistical analyses of radiopacity, expressed as mm Al (n = 15), were carried out using the Kruskal-Wallis test followed by pairwise comparisons (α = 0.05).
Radiopacities of CAD/CAM materials were, in ascending order, VE, VM II, CS, LU, and GB. At 1 mm thickness, the radiopacities of all CAD/CAM specimens were matching or slightly lower than enamel. At 2-mm thickness, the resin composite blocks were significantly more radiopaque than the ceramics VE and VM II (p < 0.0001). No statistically significant differences in radiopacity were detected between the 1-mm thick infiltrated ceramic, enamel, dentin and various resin composites except for filling and bulk fill types. The radiopacity of polymer-infiltrated ceramics was low despite the presence of radiopacifying elements and high filler content.
Identifying thin restorations in standard radiographs is necessary with the development and expanded application of 'digital' dental materials in restorative treatment. This study confirmed the joint influence of composition and thickness on radiopacity. CAD/CAM restorative materials showed thickness-dependant radiopacity. But polymer-infiltrated ceramics were fairly radiolucent. There is a need to revisit radiopacity requirements for CAD/CAM restorative materials.
本研究旨在通过（i）确定其化学成分、（ii）比较其射线不透性和（iii）将射线不透性与样本厚度相关联，来研究 CAD/CAM 修复块和其他基于树脂的材料。
从五种 CAD/CAM 和六种基于树脂的复合材料（RBC）中制备厚度为 1mm 和 2mm 的圆盘试件（n=3）。CAD/CAM 树脂复合材料包括美学类型：CeraSmart（CS）、Grandio Blocs（GB）、Lava Ultimate（LU），外加聚合物渗透陶瓷 Vita Enamic（VE）和长石质陶瓷 Vita Mark II（VM II）。六种 RBC 用于不同的临床应用：直接填充、流动、大块填充、基底和两种粘固粉。将试件与铝阶跃楔形物和牙段一起拍摄射线照片。根据 ISO 1311/2014 对每个试件的射线不透性进行数字图像分析，并确定其射线不透性。用 Kruskal-Wallis 检验后进行配对比较（α=0.05），对射线不透性（以 mm Al 表示，n=15）进行统计学分析。
CAD/CAM 材料的射线不透性依次为 VE、VM II、CS、LU 和 GB。在 1mm 厚度时，所有 CAD/CAM 试件的射线不透性与釉质匹配或略低。在 2mm 厚度时，树脂复合材料块的射线不透性明显高于陶瓷 VE 和 VM II（p<0.0001）。在 1mm 厚的渗透陶瓷、釉质、牙本质和各种树脂复合材料之间，除了填充和大块填充类型外，没有检测到射线不透性的统计学差异。尽管聚合物渗透陶瓷含有射线增感元素和高填料含量，但射线不透性仍然较低。
随着“数字化”牙科材料在修复治疗中的发展和广泛应用，在标准射线照片中识别薄型修复体是必要的。本研究证实了组成和厚度对射线不透性的共同影响。CAD/CAM 修复材料具有厚度依赖性射线不透性。但是聚合物渗透陶瓷相当透明。需要重新审视 CAD/CAM 修复材料的射线不透性要求。
