Análise da dimensão fractal do osso alveolar de pré-molares com lesão endoperiodontal: estudo piloto em radiografias periapicais digitais

Abstract

The development of periodontal damage is associated with the infection by pathogenic microorganisms and migration of its byproducts through the root canal system of the pulp and periodontal region concomitantly. This process induces on inflammatory response that can be visualized on radiographic images through radiolucent area associated with the cervical third, middle, lateral apical and also with the root apex, depending on the degree of the lesion. Fractal analysis (FA) is a quantitative method that can describe the structural arrangement of complex regions such as trabecular bone tissue and it can be numerically expressed as fractal dimension (FD) which varies from 1 to 2 for two-dimensional images. It is worth mentioning that the higher the FD value, the more complex the structure evaluated implying greater completeness of the region. There are few studies that evaluate, through FA, the complexity of bone trabeculation in teeth affected with endo- periodontal lesion (EPL). The objective of this research was to make a pilot study, using FA on digital periapical radiographs of the lower premolar region, to quantify the average commitment of the bone trabeculation in patients with endo-periodontal lesions in relation to the opposite hemi-arch, in the same region, without the lesion. Additionally, were collected data regarding the presence of periodontal disease, root damage, EPL grade and endodontic treatment, in addition to the sex and age of the patients. 19 patients who had EPL diagnosed using digital periapical radiography were selected and they should have full-mouth periapical radiographs. The images were standardized and smoothed using Image J Software and the FD of the lesion was determined using the box-counting algorithm. The regions of interest were determined by dividing the length of the tooth into four, with the division being from the most cervical point of the lesion, followed by the middle third, lateral apical and apical. The results showed that the FD values were statistically significant (p<0,05) for all simple comparisons. FA was able to quantitatively detect differences in trabecular bone architecture, since the FD of the apical third, the root apex and the mean FD of the regions of interest (ROIs) were different between the groups with and without EPL (p<0,05). Furthermore, the factors sex, age, root damage and endodontic treatment didn ́t interfere with the EPL prevalence, just the FD factor. In addition, sex, age, EPL degree and the presence of DP didn ́t interfere with FD values, only the root damage. FA was considered as a useful, precise and non-invasive tool to assess the complexity of the EPL and it favors clinical practice regarding prognosis and the treatment plan for the lesion.