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

Grant number: 19/04141-4
Support type:Scholarships in Brazil - Master
Effective date (Start): October 01, 2019
Effective date (End): September 30, 2021
Field of knowledge:Health Sciences - Dentistry
Principal Investigator:Marina Angélica Marciano da Silva
Grantee:Tamires Melo Francati
Home Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

Repair procedures represent an important aspect in Endodontics. Conservative treatments allow the maintenance of the teeth in functional conditions, preventing future occlusal alterations and bone loss. For this purpose, mineral trioxide aggregate (MTA) has been widely used. After application of these materials, calcium hydroxide is produced during fixation of the material and calcium ions interact with fluids from connective tissue and bone. MTA composition consists of tricalcium silicate, dicalcium silicate, tricalcium aluminate and bismuth oxide (BiO) as a radiopacifier. The presence of BiO implies in ion migration of such materials to adjacent tissues. The objective of the study is to evaluate the migration and local accumulation of bismuth and silicon ions after short and long periods when in contact with subcutaneous tissue and bone. A total of 64 animals will be divided into 6 experimental groups, according to the materials to be implanted and the application site. Cements in the back (n = 30) and femur (n = 30) and, according to cement, tricalcium silicate (TCS) (n = 10), ProRoot MTA (TCS-BiO) (n = 10), hydroxyapatite (HAp) with a 20% substitution of BiO (HAp-BiO) (n = 10) and a negative control group, without implantation (n = 4). Two samples with 2 x 4 mm of the same material will be implanted in the subcutaneous and inside cavities with same dimensions in the femur bone of each animal. Half of the animals (n = 35) will be sacrificed after 30 days and the remaining (n = 35) in 180 days, and both the implanted cements and the adjacent tissues (subcutaneous and femur) to the implanted cements will be collected for analysis. The implanted cements will be analyzed using X-ray diffractometry (XRD) to determine the chemical interaction with tissues. For adjacent tissues it will be used scanning electron microscopy (SEM) and local mapping of chemical elements (EDS) present after contact with the cements. The results will be submitted to appropriate statistical analysis with significance level of 5%.