Molecular aspects on host response to persistent apical periodontitis

Abstract

Genetic polymorphisms are differences in the human DNA sequence that can alter geneexpression and influence the organism's susceptibility to disease as well as its response to theenvironment. Thus, in addition to microbial and mechanical factors related to the root canalitself, intrinsic factors to the host may interfere with the success of endodontic treatment andthe need for reintervention. This study will investigate molecular aspects of periapical lesionsby means of histopathological and immunohistochemical evaluation, gene expression analysisby RT-PCR, as well as allelic discrimination by RT-PCR of saliva and cytokine dosing bymeans of an enzyme-linked immunosorbent assay (ELISA). The imaging aspects observed inthe development and progression of apical periodontitis using cone beam computedtomography (CBCT) will be used as phenotypic parameters to understand the molecularaspects involved in the etiology of persistent endodontic infection. Patients diagnosed withpulpal necrosis who, after endodontic treatment, still present persistent periapical lesions willbe selected for the study. Samples of saliva will be collected as a source of genomic DNAand, at the surgical moment, the periapical lesion will be collected. After the processing of thesamples, genotyping for RANK, RANKL, OPG, SOCS-1, SOCS-2, SOCS-3 and TNF-± willbe performed by RT-PCR, as well as histopathological classification andimmunohistochemical analysis, as well as the cytokine dosage by ELISA and gene expressionby RT-PCR. Parameters of shape, volume, area, perimeter, location and extension of thelesions will be obtained through the CBCT images. (AU)