Effect of laser and photodynamic therapy on metallic implants surface decontamination: microscopic study in rats subcutaneous tissue

• Grant number: 10/15667-2
• Support Opportunities: Regular Research Grants
• Start date: December 01, 2010
• End date: November 30, 2011
• Field of knowledge: Health Sciences - Dentistry - Oral and Maxillofacial Surgery
• Principal Investigator: Maria Lúcia Rubo de Rezende
• Grantee: Maria Lúcia Rubo de Rezende
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil
• Associated researchers: Samira Salmeron

Abstract

Even though dental implants are well established as an extremely predictable option of treatment, failures can occur due to early or late exposition of its surfaces to the oral environment. These surfaces can become infected by bacteria and its products similarly to dental roots surfaces. Such contaminating substances, when released from the implants surfaces, can intensify and perpetuate the inflammatory response. Besides, it can alter the superficial layer oxide, originating peri-implant disease or peri implantitis. Several methods of implants surfaces decontamination have been proposed for the treatment of peri-implantitis, including sand blasting, acid etches, antibiotics and lasers in different wave lengths and power settings. Nevertheless, until the moment, there is no methodology established as gold standard for this aim. The purpose of this study is to evaluate the efficacy of decontamination of low intensity laser (LBI), photodynamic therapy (PDT) and application of toluidin blue stain (TBO) on two kinds of titanium surfaces exposed to the oral environment, by the analysis of the rats' subcutaneous connective tissue response to its implantation. To reach this objective, 120 of 150 titanium discs which surfaces were treated by either machined (smooth) or sand blasted/acid etched (grooved) will be fixed to removable palatal acrylic devices that will be used by 15 volunteers during 7 days, with the aim of promoting bacterial biofilm growth on the exposed metallic surfaces. After those periods, the discs will be removed from the device, being 30 discs (15 smooth and 15 grooved) decontaminated by LBI; 30 discs (15 smooth and 15 grooved) decontaminated by PDT; 30 discs (15 smooth and 15 grooved) treated by TBO and 30 discs (15 smooth and 15 grooved) that will not receive any kind of treatment (positive control). The remaining 30 sterile discs will serve as negative controls. Then, the discs will be implanted in rats' subcutaneous connective tissue and, after 7, 28 and 84 days, specimens comprising implants and surrounding tissues will be removed and fixed in formalin 10%. After carefully removal of the metallic discs, the specimens will be submitted to conventional histology for Hematoxilin-Eosin staining. Descriptive, semi quantitative and quantitative microscopic analysis (by means of a computerized software) of the tissue reaction to discs implantation will be made. The parameters to be evaluated will be: fibrosis grade around the discs, inflammatory infiltrate index (when present), area (µm2) and thickness (µm) of the granulomatous tissue related to the surface of interest. Comparisons of the fibrosis and inflammatory infiltrate phenomenon on the discs peripheral tissue will be made by Kruskal-Wallis test. The parameters area and thickness of the granulomatous reactional tissue will be compared by analysis of variance (ANOVA) and post-test of Tukey. The significance level adopted for all tests will be 5%. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

FERREIRA, RAFAEL; DE TOLEDO BARROS, RENATO TADDEI; BRANDAO HAGE KARAM, PAULA STEPHANIA; PASSANEZI SANT'ANA, ADRIANA CAMPOS; AGUIAR GREGHI, SEBASTIAO LUIZ; RUBO DE REZENDE, MARIA LUCIA; RAGGHIANTI ZANGRANDO, MARIANA SCHUTZER; DE OLIVEIRA, RODRIGO CARDOSO; DAMANTE, CARLA ANDREOTTI. Comparison of the effect of root surface modification with citric acid, EDTA, and aPDT on adhesion and proliferation of human gingival fibroblasts and osteoblasts: an in vitro study. Lasers in Medical Science, v. 33, n. 3, p. 533-538, APR 2018. (12/06738-9, 10/15667-2)

SALMERON, SAMIRA; REZENDE, MARIA L. R.; CONSOLARO, ALBERTO; SANT'ANA, ADRIANA C. P.; DAMANTE, CARLA A.; GREGHI, SEBASTIAO L. A.; PASSANEZI, EULOIR. Laser Therapy as an Effective Method for Implant Surface Decontamination: A Histomorphometric Study in Rats. Journal of Periodontology, v. 84, n. 5, p. 641-649, MAY 2013. (10/15667-2)