Periodontal tissues response to tricalcium silicate cement associated to zirconium oxide or niobium oxide used in the sealing of furcation perforations in rat molars

Author(s)

Derik Damasceno Barbosa

• Document type: Master's Dissertation
• Press: Araraquara. 2016-06-08.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Odontologia. Araraquara
• Defense date: 2016-04-06
• Advisor: Paulo Sérgio Cerri; Guilherme Ferreira da Silva

Abstract

Accidental radicular perforation occurs in about 2-12% of endodontically treated teeth. These perforations lead to injury of periodontal tissues and frequently promote bacterial invasion inducing to periodontal ligament inflammation and bone resorption may lead to tooth loss. Among the materials suitable for the sealing of these perforations, the MTA has been widely used. MTA is basically composed of calcium silicate (80%) and bismuth oxide (Bi2O3, 20%), a radiopacifying agent. Tricalcium silicate (TCS) is a biomaterial used associated with zirconium oxide (ZrO2) and niobium oxide (Nb2O5) is an alternative radiopacifier. Our purpose was to evaluate response of the periodontium adjacent to furcation perforations in rat molars filled with pure tricalcium silicate (Mineral Research Processing, Meyzieu, France) associated with ZrO2 or Nb2O5 and MTA-Angelus. Eighty rats were distributed into four groups: SG (sham), TCS+ZrO2, TCS+Nb2O5 and MTAG according to the sealing material. In the SG group, the perforations in the pulp chamber floors were not sealed. The access cavity was restored with light-cure glass-ionomer cement. The left upper first molars, without perforations in the pulp chamber floors, were used as controls (CG). After 7, 15, 30 and 60 days, fragments of maxilla were fixed, decalcified and embedded in paraffin. In the HE-stained sections, the volume density of inflammatory cells (VvIC), fibroblasts (VvFb) and blood vessels (VvBV) was obtained. The width of the periodontal space, the birefringent collagen content and TRAP-positive osteoclasts were computed. Detection of Interleukin-6 (IL-6) by immunohistochemistry and the number of immunolabeled cells were carried out. Data were statistically evaluated using a one-way ANOVA with the post-hoc Tukey test and a significance level of p≤0.05. The highest values of VvIC, TRAP-positive osteoclasts and IL-6 immunolabeled cells were observed in the periodontal ligament adjacent to furcation perforations (with or without sealing) in the period of 7 days. A significant increase in the width of the periodontal space was observed in molars with furcation perforations. At 60 days, a significant reduction in the VvIC, immunoexpression for IL-6, osteoclasts number and in the width of periodontal space in MTAG, TCS+ZrO2 and TCS+Nb2O5 groups was observed when compared with the period of 7 days. In these groups, a significant increase in VvFb and collagen content was observed in the periodontal ligament. At 60 days, the VvIC and the periodontal space were significantly lower in the TCS+ZrO2 and TCS+Nb2O5 compared with MTAG. In addition, significant differences in the immunoexpression for IL-6 were not observed between TCS+ZrO2, TCS+Nb2O5 and CG, while the mean value was significantly higher in the MTAG than CG. Therefore, tricalcium silicate material containing 30% zirconium oxide or niobium oxide promotes an inflammatory process regression stimulating more efficiently the periodontal tissues repair than MTA material. (AU)

• FAPESP's process: 14/14688-7 - Periodontal tissues response to tricalcium silicate cement associated to zirconium oxide or niobium oxide in rat molars
• Grantee: Derik Damasceno Barbosa
• Support Opportunities: Scholarships in Brazil - Master