In vivo evaluation of the local migration of bismuth and silicon ions present in repair cements in contact with connective tissue and bone

Author(s)

Tamires Melo Francati

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2022-08-04

Examining board members

Marina Angélica Marciano; Brenda Paula Figueiredo de Almeida Gomes; Clarissa Teles Rodrigues

• Advisor: Marina Angélica Marciano

Abstract

Mineral trioxide aggregate (MTA) is a cement used in endodontics in reparative procedures, composed of tricalcium silicate, dicalcium silicate, tricalcium aluminate and the radiopacifier bismuth oxide. The aim of this study is to evaluate the migration and local accumulation of bismuth (Bi) ions after contact with connective tissue and bone. The study also evaluated the hypothesis that the bismuth migration mechanism is associated with silicon (Si). A total of 64 Wistar rats were divided into experimental groups according to the implantation site: connective and bone, and with the implanted cements: tricalcium silicate (TCS) (n=20), ProRoot MTA (MTA) (n=20) , hydroxyapatite with 20% bismuth oxide (HAp-Bi) (n=20), and negative control, without implantation (n=4). The animals were sacrificed after 30 (n=32) and 180 days (n=32). The methodologies used to evaluate the migration of Bi and Si in both tissues were X-ray fluorescence spectrometry (XRF), inductively coupled plasma mass spectrometry (ICP-MS), chemical characterization by means of Raman spectroscopy and histological analysis of tissue response. Statistical analysis of the results of the multi-element evaluation in ICP-MS and of the histological evaluation was performed considering a significance level of 5% (p < 0.05). XRF analysis demonstrated the migration of Bi from MTA and HAp-Bi towards connective tissue and bone, suggesting that this migration occurs independently of Si, as the HAp-Bi group does not present this element. In the ICP-MS analysis, for the MTA and Hap-Bi group, it was possible to detect bismuth in the connective and bone tissues in both periods. For connective tissue, there was no statistical difference between the MTA and Hap-Bi groups for bismuth (p > 0.05). The silicon element was detected in all groups, with a higher mass fraction in the connective tissue after 30 days for the TCS and MTA groups, but with no statistical difference between them (p > 0.05). Raman analysis showed small signs of change for all implanted materials at 180 days, regardless of implantation site. Histologically, elevated inflammation was observed at 30 days for all experimental groups, in both tissues. However, at 180 days in bone tissue, this inflammation significantly reduced (p < 0.05). Contact of ProRoot MTA cement with connective and bone tissue results in bismuth migration. However, the migration mechanism of this element suggests that it can occur independently of silicon (AU)

• FAPESP's process: 19/04141-4 - In vivo evaluation of the local migration of bismuth and silicon ions present in repair cements in contact with connective tissue and bone
• Grantee: Tamires Melo Francati
• Support Opportunities: Scholarships in Brazil - Master