Evaluation of the gray level of restorative materials using cone-beam computed tomography: A cross-sectional study

Densitometry plays an important role in the diagnosis and treatment planning. Due to diversity in density, equal amounts of different materials absorb various amounts of X-rays and yield different radiographic views. The aim of this study was to evaluate the gray scales of 5 commercially available restorative materials, including amalgam, composite resin, flowable composite resin, glass-ionomer, and Dycal. Samples of the 5 test materials from various manufacturers were prepared, each 5-millimeter-thick. There were 7 glass-ionomer samples and 10 of each of the other materials, making a total of 47 samples in the study. The test materials were scanned using a Kodak cone-beam computed tomography (CBCT) unit. Subsequently, the gray scales were determined and evaluated by a radiologist using OnDemand3DTM Dental software and analyzed with SPSS v. 22 software. Amalgam had a higher gray scale than the other groups of restorative materials. In some cases, it was the same as that of composite resin; however, it was significantly different from gray scales of flowable composite resin, glass-ionomer and Dycal. It was concluded that composite resin and amalgam were high in gray scale, while flowable composite resin, glass-ionomer and Dycal exhibited low gray scales. Amalgam and composite resin had high gray scales, and glass-ionomer and Dycal exhibited the lowest gray scale values. The findings show that CBCT can be helpful in differentiating amalgam and composite resin from other materials.