Cruz A D, Esteves R G, Poiate I A V P, Portero P P, Almeida S M
Oper Dent. 2014 Jan-Feb;39(1):90-7. doi: 10.2341/12-377-L. Epub 2013 May 28.
This study aimed to objectively evaluate the radiopacity of different dental composites and their subjective influence on diagnosing secondary caries-like lesions and how these results correlate. For objective analysis, three resin specimens (1 mm thick, with a 4-mm internal diameter) were made with four composites: 1) Charisma; 2) Filtek Z250; 3) Prisma AP.H; and 4) Glacier. Three human teeth were selected and then mesio-distally sectioned (1 mm thick) to make the dental specimens. An aluminum (Al) wedge (12 steps, 1 mm thick, 99.8% purity) was used as an internal standard to calculate the radiopacity. For subjective analysis, 20 human teeth were selected and then prepared with a mesio-occluso-distal (MOD) inlay cavity, with half the teeth receiving a round cavity to simulate the carious lesion. The MOD was restored using the composites at four different times. Standardized radiographs were acquired and then digitized (300 dpi and eight-bit TIFF) for both analyses. A histogram objectively measured the pixel intensity values of the images, which were converted into millimeters of Al using linear regressions. Eight observers subjectively evaluated the images using a five-point rating scale to diagnose the caries. The data were statistically analyzed using the Student t-test, the Kappa test, diagnostic testing, and the Pearson correlation coefficient (α=0.05). All materials showed radiopacity values compatible with dental tissues (p>0.05); Glacier was similar to dentin and Prisma AP.H was similar to enamel, while the remaining materials showed a middle radiopacity. Prisma AP.H and Glacier differed (p<0.05) in relation to their accuracy to caries diagnosis, with Glacier having greater accuracy. There was a correlation between objective and subjective analyses with negative linear dependence. An increase in the material's radiopacity could have a subjectively negative influence on the diagnosis of secondary caries; thus, an ideal radiopacity for a dental composite is closer to the dentin image and produces similar attenuation to X-rays than does dentin.
本研究旨在客观评估不同牙科复合材料的射线不透性及其对继发性龋样病变诊断的主观影响，以及这些结果之间的相关性。为进行客观分析，用四种复合材料制作了三个树脂标本（厚1毫米，内径4毫米）：1）卡瑞斯玛；2）3M纳米树脂Z250；3）普瑞玛AP.H；4）冰川。选取三颗人牙，然后沿近远中方向切成（厚1毫米）牙科标本。使用铝（Al）楔形块（12级，厚1毫米，纯度99.8%）作为内标来计算射线不透性。为进行主观分析，选取20颗人牙，然后制备近中-咬合-远中（MOD）嵌体洞形，其中一半牙齿制备圆形洞形以模拟龋损。在四个不同时间使用复合材料修复MOD洞形。获取标准化X线片，然后进行数字化处理（300 dpi和8位TIFF格式）用于两种分析。通过直方图客观测量图像的像素强度值，并使用线性回归将其转换为铝的毫米数。八位观察者使用五点评分量表主观评估图像以诊断龋齿。使用学生t检验、kappa检验、诊断试验和皮尔逊相关系数对数据进行统计分析（α = 0.05）。所有材料的射线不透性值均与牙体组织相符（p>0.05）；冰川与牙本质相似，普瑞玛AP.H与牙釉质相似，而其余材料显示中等射线不透性。普瑞玛AP.H和冰川在龋齿诊断准确性方面存在差异（p<0.05），冰川具有更高的准确性。客观分析和主观分析之间存在负线性相关。材料射线不透性的增加可能对继发性龋齿的诊断产生主观负面影响；因此，牙科复合材料的理想射线不透性更接近牙本质图像，并且与牙本质相比对X射线产生相似的衰减。
