Purpose: This study evaluated how restorative materials-specifically, lithium disilicate (LD) (IPS e.max; Ivoclar Vivadent, Liechtenstein, Switzerland) and zirconia-affect the contrast-to-noise ratio (CNR) in cone-beam computed tomography (CBCT) imaging. Materials and Methods: CNR was compared between LD and zirconia (NexxZr T; Sagemax Bioceramics, Federal Way, USA; and Zirlux Transitions; Zahn Dental, New York, USA) using 2 CBCT machines-Planmeca ProMax 3D Mid 2015 (Planmeca, Helsinki, Finland) and PreXion 3D Excelsior (PreXion Inc., San Mateo, USA)-under multiple exposure settings, with and without metal artifact reduction (MAR). Four cylindrical ingots were scanned in a saline phantom under 10 conditions (Planmeca: Low, Normal, High, ±MAR; PreXion: Rapid, Standard, HD, UHD). CNR was calculated in ImageJ (National Institutes of Health, Bethesda, MD, USA) and analyzed with the paired t-test. Results: LD showed the highest CNR on Planmeca without MAR and across all PreXion settings. With MAR on Planmeca, zirconia outperformed LD. For zirconia, CNR improved with larger voxel sizes and MAR, whereas for LD it was optimal with smaller voxel sizes and MAR. Optimal Planmeca settings were Low (400 μm) + MAR for zirconia and High (150 μm) + MAR for LD. On PreXion, Rapid (200 μm) favored zirconia, while HD (100 μm) favored LD. Conclusion CBCT settings should be tailored to the restorative material, diagnostic need, and radiation dose. For zirconia, larger voxel sizes with MAR enhance CNR; for LD, smaller voxel sizes with MAR are optimal. Thesefindings support imaging optimization for patients with dental restorations.

Purpose: The aim of this study was to assess artifacts generated in cone-beam computed tomography (CBCT) of 3 types of dental implants using 3 metal artifact reduction (MAR) algorithm conditions (pre-acquisition MAR, postacquisition MAR, and no MAR), and 2 peak kilovoltage (kVp) settings. Materials and Methods: Titanium-zirconium, titanium, and zirconium alloy implants were placed in a dry mandible. CBCT images were acquired using 84 and 90 kVp and at normal resolution for all 3 MAR conditions. The images were analyzed using ImageJ software (National Institutes of Health, Bethesda, MD) to calculate the intensity of artifacts for each combination of material and settings. A 3-factor analysis of variance model with up to 3-way interactions was used to determine whether there was a statistically significant difference in the mean intensity of artifacts associated with each factor. Results: The analysis of all 3 MAR conditions showed that using no MAR resulted in substantially more severe artifacts than either of the 2 MAR algorithms for the 3 implant materials; however, there were no significant differences between pre- and post-acquisition MAR. The 90 kVp setting generated less intense artifacts on average than the 84 kVp setting. The titanium-zirconium alloy generated significantly less intense artifacts than zirconium. Titanium generated artifacts at an intermediate level relative to the other 2 implant materials, but was not statistically significantly different from either. Conclusion This in vitro study suggests that artifacts can be minimized by using a titanium-zirconium alloy at the 90 kVp setting, with either MAR setting.

PURPOSE: The purpose of this study was to evaluate and compare the efficacy of cone-beam computed tomography (CBCT) and digital intraoral radiography in diagnosing simulated small external root resorption cavities. MATERIALS AND METHODS: Cavities were drilled in 159 roots using a small spherical bur at different root levels and on all surfaces. The teeth were imaged both with intraoral digital radiography using image plates and with CBCT. Two sets of intraoral images were acquired per tooth: orthogonal (PA) which was the conventional periapical radiograph and mesioangulated (SET). Four readers were asked to rate their confidence level in detecting and locating the lesions. Receiver operating characteristic (ROC) analysis was performed to assess the accuracy of each modality in detecting the presence of lesions, the affected surface, and the affected level. Analysis of variation was used to compare the results and kappa analysis was used to evaluate interobserver agreement. RESULTS: A significant difference in the area under the ROC curves was found among the three modalities (P=0.0002), with CBCT (0.81) having a significantly higher value than PA (0.71) or SET (0.71). PA was slightly more accurate than SET, but the difference was not statistically significant. CBCT was also superior in locating the affected surface and level. CONCLUSION: CBCT has already proven its superiority in detecting multiple dental conditions, and this study shows it to likewise be superior in detecting and locating incipient external root resorption.
Cone-Beam Computed Tomography* ; Radiographic Image Enhancement ; Radiography* ; Radiography, Dental, Digital ; ROC Curve ; Root Resorption* ; Tooth