Diagnostic performance of periapical radiographs in digitized simulated bone loss in apical region

Abstract

The aim of this study was to evaluate the performance of pe- riapical radiographs in the diag- nosis of digitally simulated bone loss. Thirty premolar and molar mandibular teeth apexes, without radiolucences, were selected from files. The radiographs were digiti- zed at 8 bits, 256 gray levels, 300 dpi and stored in JPEG 12 format. In the original image the selec- ted apical areas were marked out with a square, the images were reproduced seven times and num- bered sequentially, forming eight groups. The bone loss was digi- tally simulated with pencil tool (mechanic model) and spray tool (chemical model), with black ink, 3%, 5% and 8% intensities. Three observers evaluated at different moments the image pairs (initial and experimental) and the sub- tracted images. Twenty percent of the images were reanalyzed. The Spearman’s Correlation Co- efficient Test and Wilcoxon’s ma- tched-pairs Test demonstrated, for both models, a good intra and inter-observer reproducibility with exception to one observer. The ROC´s curves (p> 0,05) analy- ses showed a significant difference between both models for 3% and 5% intensities. There was not sig- nificant difference for 8% intensity. The qualitative digital subtraction showed better performance than radiographs image pair analysis in both models of simulated light and moderate resorption. Key words: Periapical tissue, den- tal radiograph, digital radiograph subtraction technique.