Effects of chemical treatment of surfaces in decontamination of metallic implants: microscopic study in subcutaneous rats

Author(s)

Rafael Mansano de Castro Lara

• Document type: Master's Dissertation
• Press: Bauru.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Bauru (FOB/SDB)
• Defense date: 2012-03-09

Examining board members

Sebastiao Luiz Aguiar Greghi; Carla Andreotti Damante; Daniel Romeu Benchimol de Resende

• Advisor: Sebastiao Luiz Aguiar Greghi

Abstract

The purpose of this investigation was to evaluate the effects of treatment with citric acid, tetracycline, EDTA and phosphoric acid in titanium disks in smooth and roughened surfaces contaminated by bacterial biofilms in the connective tissue of rats. One hundred eighty titanium disks were used; 90 smooth surfaces and 90 roughened titanium surfaces, which were placed in 19 acrylic plates that were used by volunteers for 7 days. These disks were divided into 12 groups containing 15 disks each; Group 1L: 15 smooth disks were treated with citric acid; Group 1R: 15 roughened disks were treated with citric acid; Group 2L: 15 smooth disks were treated with tetracycline acid; Group 2R: 15 roughened disks were treated with tetracycline rough acid; Group 3L: 15 smooth disks were treated with EDTA; Group 3R: 15 roughened disks were treated with EDTA; Group 4L: 15 smooth disks were treated with phosphoric acid; Group 4R: 15 roughened disks were treated with phosphoric acid; Group CL: 15 smooth disks received no econtamination (smooth positive control); CR: 15 roughened disks did not receive decontamination (roughened positive control); EL: 15 smooth disks were not infected (smooth negative control) and ER: 15 roughened disks were not infected (roughened negative control). These disks were implanted subcutaneously in rats that were sacrificed after 7, 28 or 84 days. A descriptive and quantitative microscopic evaluation was performed. The average thickness of the capsules and the density of fibroblasts and neutrophils in three time periods were evaluated. The results showed differences in the density of neutrophilis mainly at 7 days and phosphoric acid showed the best results in this period, and at the end of 84 days, all treatments showed similar results even with the control group infected. In relation to the roughness, the smooth disks had a lower average capsule thickness compared with roughened disks, perhaps demonstrating an aspect of greater biocompatibility smooth surface, which would suggest greater effectiveness in decontamination of smooth disks. (AU)

• FAPESP's process: 09/12942-5 - Effects of Chemical Treatment of Surfaces in decontamination of metallic implants. Microscopic Study in Subcutaneous rats.
• Grantee: Rafael Mansano de Castro Lara
• Support Opportunities: Scholarships in Brazil - Master