Influence of Windowing and Evaluation of Metal Artifact Reduction Algorithm on Five Different Restorative Materials by Using Different Cone Beam Computed Tomography (CBCT) Scanners: A CBCT Study

Objectives: To assess the influence of windowing, and to evaluate, and compare the effect of the metal artifact reduction (MAR) and non-metal artifact reduction (non-MAR) algorithms on different high-density restorative dental materials using different cone beam computed tomography (CBCT) devices. Material and method: Height and diameter of all cylindrical shape metals including amalgam, cobalt-chromium, composite, gutta-percha, and titanium were measured using a digital caliper device. Polymethylmethacrylate block and arch phantom with a cylindrical-shaped perforation containing five different metals were submitted to tomographic acquisition with six different cone beam computed tomographic devices in small fields of view with their MAR enabled and disabled. Windowing was done using ITK-SNAP software (3.8.2) which was used as a contrast medial tool for window level and window width. The data was analyzed for probability distribution using the Kolmogorov-Smirnov test, where a p-value of <0.05 indicated that the data were not normally distributed. The comparison of length and width was done using the Wilcoxon sign rank test. Comparison of categorical variables was done using the Chi-square test where a p-value of <0.05 was considered statistically significant. Results: Length and width of all these metals measured using MAR and non-MAR CBCT were found to be statistically non-significant (p-value of >0.05). MAR algorithm significantly reduces metals artifact produced by high-density restorative materials (p-value of <0.05). Conclusion: Amalgam and cobalt-chromium produced more artifacts while composite and gutta-percha did not produce enough artifacts to be reduced by the MAR algorithm. Large window width and high window level would be beneficial to reduce the metal artifact.