Optimization of CBCT tube current parameters for the assessment of regions at different distances from dental implants and peri-implant bony defects

Abstract

Dental implants, as well as other high-density materials, generate artifacts that degrade image quality in cone beam computed tomography (CBCT) examinations. Therefore, in implant rehabilitation, postoperative CBCT is only recommended in clinical situations that involve failures or complications. The presence of artifacts may also interfere with the diagnosis when CFCT exams are performed due to other clinical indications and dental implants are present in areas adjacent to those that will be evaluated. In tomographic examinations, the use of higher tube currents (mA) generally improves image quality. However, there is a direct relationship between mA and radiation dose employed. The evaluation of the effect of variations in mA for specific diagnostic tasks is therefore relevant for optimal use of CBCT. The objective of this study is to evaluate the effect of mA of CBCT exams on the magnitude and extent of artifacts generated by dental implants, and on the diagnostic accuracy of peri-implant bone defects (dehiscence and fenestrations). To evaluate the effect of mA on the magnitude and extent of artifacts, mandibles will be scanned before and after the installation of titanium implants, with different mA parameters (4 to 13mA). An objective analysis will be carried out to analyze the effect on mean and standard deviation of gray values in 12 regions of interest of the images at different distances and positions in relation to the implant. To evaluate the effect of mA in the diagnosis of peri-implant defects, bovine rib segments with implants with and without defects (fenestrations and dehiscences) will be scanned with different tube currents (4 to 13mA). Five observers will score, on a 5-point scale, the segments regarding the presence of defects. Sensitivity, specificity and area under the receiver operating characteristics (ROC) curve will be calculated for the different mA parameters. (AU)