Importância da limpeza, método e momento de alívio do canal radicular para instalação do pino de fibra de vidro: revisão sistemática e estudo laboratorial

Abstract

For installation of intra-radicular post it is necessary space preparation removingobturation, which can be performed immediately or after a few days. However, this post space preparation can generate apical displacement of the obturation and generate residues interfering in the adhesion of the fiberglass. There is no consensus in the literature what is the best solution to remove residues after the post space preparation. Therefore, the present project was divided into laboratory study and systematic review. The first one had as objectives to evaluate the effect of the immediate and delayed post space preparation performed with drill or thermocompactador (Thermo)on the presence of residues and on the apical displacement of the obturation in teeth obturated by the single cone technique and randomized divided in 6 groups (n=5). For this purpose, 30 bovine incisors were used, which were instrumented with Reciproc R50 and filled by the single cone technique. Immediate with term (IT), Immediate with drill (IB), delayed with term (TT), delayed with drill (TB), positive control filled with no post space preparation) and negative control (instrumented without root filling. The post space preparationswere performed up to 30 minutes after obturation in the immediate group and 14 days after obturation in the delayed group.The teeth were scanned before and after the post space using MicroCt, the images were reconstructed and analyzed statistically. The single-factor analysis of variance showed a significant difference (P ≤0.05) between the experimental groups. G2 had the lowest amount of residues in the apical third when compared to the other groups (P ≤0.041). In relation to the positive and negative control groups, these presented statistically significant differences when compared to each other, and with the experimental groups, in all thirds evaluated (P ≤0.001). Regarding the apical displacement there was no statistical difference between the groups (P≥ 0.05). Considering the limitations of the present in vitro study, the results allow to conclude that delayed of the post space preparationusing therm resulted in higher residues in the middle and apical third of the root canal, while the smaller amount of residues was observed in the G2. Regarding the apical displacement, no difference was observed between the groups. All methods used for post space prepation resulted in displacement of the obturation.The second part of this study, systematic review involved in vitro studiesto investigate if cleaning methods can increase the retention of FGPs evaluated by push-out test.Searches were carried out in PubMed (MEDLINE) and Scopus data-bases up to July2017. A total of 475 studies were found, 09 were included in this review. From the 9 studies were collected, five studies presented the best results for the association of sodium hypochlorite (NaOCl) and ethylenediamine tetra-acetic acid(EDTA). The results showed heterogeneity in all comparisons due high variety of informations about cleaning methods, different concentrations, application time, type of adhesive system and resin cements used. In conclusion, this review suggest that the use of NaOCl/EDTA,activated or not, results in hight retention of FGP sand may be recommended as a post-space cleaning method influencing the luting procedure of fiber post.