Influence of chronic stress on tissue response of endodontic sealers

Author(s)

Mariana Pagliusi Justo

• Document type: Master's Dissertation
• Press: Araçatuba. 2023-02-28.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Odontologia. Araçatuba
• Defense date: 2023-02-27
• Advisor: Luciano Tavares Angelo Cintra

Abstract

Objective: This study aimed to correlate chronic stress with the tissue response of different types of endodontic cements using the ISO 10993-6:2016 model for subcutaneous tissue implantation tests. Methods: 28 Wistar rats were used, divided into two groups (n=14): control rats (rC) and stressed rats (rE). Four polyethylene tubes were implanted in each rat, 1 empty for control, and the others containing one of the endodontic cements selected for the study (Sealapex®, Endofill® and AH Plus®). The evaluation periods were 7 and 30 days (n=7/time). After euthanasia, blood was collected for corticosterone dosage by the ELISA method, and then the tubes and surrounding tissue were removed and processed for histological and immunohistochemical analysis. Inflammation was assessed in tissue sections stained in H.E. and by immunohistochemical staining for IL-6, IL-17, TNF-α, CD8 and CD20; collagen, by Picrosirius red staining (PSR); biomineralization, by von Kossa staining (vK) and in sections without staining by polarized light (POL), as well as by osteocalcin (OCN) analysis. For all tests employed, a significance level of 5% (p<0.05) was considered. Results: An increase in corticosterone was observed in rE compared to rC, only in the 7-day period (p < 0.05). Animals in the rE group less body weight gain compared to animals in rC (p < 0.05). Histological analysis in rC at 7 days showed that the Endofill group showed more intense inflammatory infiltrate compared to Control (p = 0.031). In rE there was no difference between the groups in any period (p > 0.05). Comparing the response of each group according to the presence or absence of stress, it was observed that only at 7 days the control group in rE presented a more intense inflammatory infiltrate than the Control group in rC (p < 0.005). There was no difference between groups for IL-6 in any of the comparisons and periods (p > 0.05). For IL-17 in rC, at 7 days, the Endofill group showed more intense inflammatory infiltrate compared to the Control (p < 0.05). For TNF-α, it was observed at 7 days that the control group in rE showed greater immunolabeling compared to the Control group in rC (p < 0.05). For CD8, at 30 days, it was observed that the AH Plus group in rC showed a greater amount of CD8+ cells compared to AH Plus in rE (p < 0.05). For CD20 in rC, at 7 days, the Endofill group had more CD20+ cells when compared to the Control and Sealapex groups (p < 0.05). In rE, at 7 days, it was observed that the Endofill group presented a greater amount of CD20+ cells when compared to the Control group (p < 0.05). At 7 days, the Control group in rC presented a greater amount of CD20+ cells compared to the Control group in rE (p < 0.05). For PSR, when comparing the groups in rC, at 7 days, the Sealapex and Endofill groups showed a higher percentage of immature fibers and a lower percentage of mature fibers when compared to the Control and AH Plus groups (p < 0.05). The Control, Sealapex and Endofill groups in rE showed a higher percentage of immature fibers and a lower percentage of mature fibers compared to the Control, Sealapex and Endofill groups in rC (p < 0.05). The AH Plus group in rE, both at 7 days and 30 days showed a higher percentage of immature fibers and a lower percentage of mature fibers compared to the AH Plus group in rC (p < 0.05). Only in the Sealapex group, both in rC and rE, structures stained black in von Kossa staining, birefringent crystals under polarized light and positive immunostaining for OCN were observed. Furthermore, in rC there was greater immunostaining for OCN compared to rE (p < 0.05). Conclusion: Chronic stress influenced the tissue response of endodontic sealers, increasing the inflammatory infiltrate and delaying tissue repair. Still, chronic stress reduced the biomineralization capacity of the material that has this ability. (AU)

• FAPESP's process: 21/03861-3 - Influence of retention stress on the tissue response of endodontic sealers
• Grantee: Mariana Pagliusi Justo
• Support Opportunities: Scholarships in Brazil - Master