Influência de artefatos na identificação de gaps em restaurações indiretas avaliadas em imagens de tomografia computadorizada de feixe cônico

Abstract

In cases of oral rehabilitation in which there is great loss of dental tissue, indirect crowns are indicated and their clinical success depends on good adaptation of the restorative material. There is no standard tool for assessing marginal adaptation of restorations and clinical and radiographic examinations are indicated. Currently, cone beam computed tomography (CBCT) images are outstanding because they allow highly accurate three-dimensional evaluation. However, in the presence of high-density materials formation of artifacts occurs. The aim of the present study was to evaluate the quantity of artifacts generated by different restorative materials, and to determine the accuracy of CBCT scans and periapical radiographs in identifying peripheral gaps. For this purpose, a mandible containing teeth restored with metal-ceramic and all-ceramic crowns, properly adapted and with 0.30 and 0.50 mm gaps, underwent CBCT exams (with voxel sizes of 0.25 and 0.30 mm) and periapical radiographs. The artifacts generated by the different crowns were quantified and compared by the MannWhitney test. In addition, five examiners evaluated the presence or absence of gaps in different imaging exams. The accuracy of tests was determined by the area under the ROC curve and these values were compared by using the Kruskal-Wallis test. The results showed that there was no significant difference in artifact values between the different restorative materials and the different resolutions of CBCT images. Regarding the accuracy of the tests evaluated, periapical radiography and CBCT with voxel size 0.25 mm showed the best performance for smaller gaps (0.30 mm). For larger gaps (0.50 mm), all exams tested showed the same performance. It could be concluded that periapical radiography was still the most cost-beneficial method for the diagnosis of maladaptation in dental restorations. However, although CBCT with voxel size 0.25 mm is not the first choice for gap diagnosis, if the patient already has these images that were taken for other indications, they could be used to evaluate possible marginal mismatches.