Evaluating the Affect of Tube Current's on Different Dental Material Artifacts in Cone Beam Computed Tomography Using Signal Difference to Noise Ratio Index

Artifacts from various dental materials are a disturbing factor which reduces the quality of images obtained from cone beam computed tomography (CBCT). This study aimed to evaluate the effect of tube current on dental material artifacts in CBCT imaging. To assess the amount of artifacts, signal difference to noise ratio indicator was used.
In this study, twenty widely-used dental materials were used. The samples were scanned with Soredex SCANORA 3D at two different tube current of 5 and 10 mA while all other conditions remained constant. Using the On-Demand 3D Application software, the circular areas were selected as the region of interest (ROI) at 1, 2 and 4 mm from the edge of the object’s image. In each of these ROI areas, information about mean gray value was obtained and signal difference to noise ratio (SDNR) was calculated. Data regarding two scanning conditions were compared using the Wilcoxon statistical analysis.
Regardless of the type of material at 5 mA, SDNR at distances of 1, 2 and 4 mm were .6797, -1.2901, and -2.8608, respectively. SDNR at 10 mA scanning at a distance of 1, 2 and 4 mm were .2363, -1.1889, and -1.1844, respectively. SDNR for all materials at 5 and 10 mA scanning condition were -0.1570, and .2877, respectively and according to the Wilcoxon test there was significant difference (P value = 0.026).
By varying tube current from 5 to 10 mA, SDNR index, and regardless of the type of material, the distance and direction increased. This increase reflects the reduction of artifacts from various dental materials following increase in tube current.