Efeito da miliamperagem em tomografia computadorizada de feixe cônico na avaliação de enxerto ósseo ao redor de implantes dentários

Abstract

Cone Beam Computed Tomography (CBCT) images allow three-dimensional evaluation of tissue around implants; however, the distinction between bone tissue and graft materials may be compromised by image artifacts caused by implant materials, which have high density and atomic number. Adjusting exposure parameters in CBCT can reduce radiation exposure levels for the patient and also influence the quality and noise of the acquired images. The modification of milliamperage (mA) is directly related to these factors and can assist in the evaluation of CBCT images with image artifacts. This study aimed to evaluate the influence of CBCT’s mA on detecting bone graft dehiscence adjacent to titanium and zirconia dental implants. Twenty titanium and twenty zirconia implants were installed in bovine rib blocks. At least 2-mm gaps were created between the implants and the bone and filled with particulate autogenous bone grafts. In half of the blocks, the gap was filled entirely and in the other half, the grafting material was removed up to the third implant thread on the buccal side. CBCT images were acquired at kilovoltage (kV) 90kV, field of view 6x4cm, voxel size 0.133mm, and milliamperage 4, 6.3, and 10 mA and assessed by 5 observers to detect bone graft dehiscence. The area under the curve AUC, accuracy, sensitivity, and specificity were calculated and compared between the variation factors (dental implant material and mA) using a two-way analysis of variance with a significance level of 5%. There were no statistically significant differences considering the different types of implants and mA (p<0.05). In conclusion, a protocol with lower radiation exposure (i.e., lower mA) can be used; however, the use of CBCT for evaluating bone graft dehiscence adjacent to different types of implants is still questionable and should be approached with caution.