Influência do uso combinado do EDTA em procedimento endodôntico regenerativo: estudo experimental em modelo animal e revisão sistemática

Abstract

The objectives of this study were: 1. To evaluate the influence of the use of ethylenediaminetetraacetic acid (EDTA) in the repair process after pulp revascularization in immature rat molars, by evaluating mineralized tissue formation, presence of inflammatory infiltrate, and the presence/maturation of collagen fibers; 2. To evaluate the influence of EDTA in the presence of growth factors after pulp revascularization in immature molars of rats, by analyzing the immunolabelling of transforming growth factor (TGF)-β1 and fibroblast growth factor (FGF)-2; 3. To evaluate the influence of the use of EDTA on the factors associated with the regenerative endodontic procedure, through a systematic review. For experimental analyses, lower right or left molars of 12 Wistar rats (4-week-old) had pulp tissue removed, and they were randomly separated in the groups (n = 6): NaOCl - irrigation with 2.5% NaOCl; and NaOCl-EDTA - 2.5% NaOCl followed by 17% EDTA. Afterwards, blood clot was induced by inserting a 15 K-file beyond the apex, and teeth were sealed. Lower untreated molars from these animals were randomly selected as control (control-15d; n = 3). Other lower right or left molars of other three animals that did not receive any intervention, they were used as control-immediate (n = 3). After 15 days, the rats from the experimental and the control-15d groups were killed; animals from control-immediate group were killed immediately at the experimental period. The jaws were prepared for histological (haematoxylin-eosin); collagen analysis (picrosirius red and Masson’s trichrome); and immunohistochemical analyses (TGF-β1 and FGF-2). Data were submitted to statistical tests (p<0.05). For systematic review, two authors independently performed a search in electronic databases (up to February-2021), data extraction and risk of bias evaluation. The release of growth factors was the primary outcome. Regarding mineralized tissue formation, NaOCl-EDTA group had more specimens with a concomitant increase in root thickness and length, and all specimens from the experimental groups showed neoformed cementum-like tissue; however, some specimens of NaOCl showed partial apical closure, while NaOCl-EDTA had complete apical closure. Most specimens from the experimental groups had inflammatory infiltrate extending to the middle third of root canals. A significant tissue neoformation was observed in the NaOCl-EDTA specimens (p<0.05). For collagen, the NaOCl-EDTA group showed more collagen fibers in the root tip, without significant difference compared to NaOCl group, where both groups showed greater amount of immature fibers in this region; in the center of the apical third, there was similar amount of mature and immature fibers from both groups, without significant differences. There was significant TGF-β1 immunolabeling in the NaOCl-EDTA group compared to NaOCl group (p<0,05), but there was no significant difference in FGF-2 immunolabeling. In conclusion: 1. EDTA positively influenced the presence of newly formed tissue in root canals after pulp revascularization, but it did not influence collagen maturation; 2. EDTA influenced TGF-β1 immunolabeling, but it did not influence FGF-2; 3. The systematic review showed that the use of EDTA can enhance TGF-β release from dentin, in addition to increase cell migration, adherence and differentiation.