Longevity of enzymatic activity and bond strength in dentin treated with EDC, chitosan and proanthocyanidin prior to cementation of fiberglass posts in teeth submitted to radiotherapy

Abstract

The objective of the present study will be to evaluate the effect of carbodiimide (EDC), chitosan and proanthocyanin on the adhesive interface of fiberglass posts luted with etch-and-rinse resin cement - RelyX ARC in teeth submitted to radiotherapy in relation to: the longevity of enzymatic activity of radicular dentin, the bond strength by push-out test, the failure pattern occurred after the push-out test by stereomicroscope, and the quality of the adhesive interface by confocal laser scanning microscopy (CLSM). Eighty single-rooted teeth with circular root canal will be selected and divided into 2 groups: non irradiated (n=40) and irradiated (30 cycles of 2Gy, total 60Gy) (n=40). The teeth will be sectioned, standardizing the length of the roots (16 mm). The roots will be instrumented with Reciproc (R50) and filled with AH Plus. Then, the preparation for the post will be carried out and the roots will be redistributed into 4 subgroups (n=10) according to dentin treatment for 60 seconds prior to the cementation of the posts: distilled water, chitosan 0.2%, EDC 0.5 M and proanthocyanidin 5%. After drying the root canal, fiberglass posts will be luted with RelyX ARC. Then, slices of 1.0 mm (± 0.1 mm) will be obtained. The first and second slices of each third will be used for immediate push-out testing and after 12 months followed by failure pattern analysis (n=10). These slices will be distributed so that in half of the roots of each group the first slice will be used for immediate analysis and the second for analysis after 12 months, while in the other half of the roots of each group the second slice will be used for analysis. immediate and the first for analysis after 12 months. The third slice of each third will be destined for analysis of the adhesive interface in CLSM, the enzymatic activity through zymography in situ immediately (n=5) and after 12 months (n=5), and the expression of MMPs-2 and -9 through immediate immunofluorescence (n=5) and after 12 months (n=5). Enzymatic activity and bond strength data will be expressed as average values and subjected to normality and homogeneity of variance tests. If the data are normal, the factors 'dentin treatment', 'radiotherapy' and 'moment' will be compared with repeated measures ANOVA. Furthermore, if the data are normal, the factors 'dentin treatment', 'radiotherapy' and 'root third' will be compared with repeated measures ANOVA. However, if the data is not normal, the Friedman test will be used. The chi-square test will be used to evaluate the association between the type of failure and the variables 'dentin treatment' and 'radiotherapy'. The McNemar test will be used to evaluate the association between the type of failure and the variables 'moment' and 'root third'. The Kruskal-Wallis test will be used to evaluate the adaptation of the adhesive interface. The Jamovi v.1.6.23 program will be used for statistical analysis, with a significance level of 5%.