Osteoblastic cell adhesion on implant surfaces contaminated by Aggregatibacter actinomycetencomitans and treated by photodynamic therapy and chemical decontamination

• Ano de defesa: 2018
• Autor(a) principal: Balderrama, Ísis de Fátima
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Decontamination; Dental implants; Descontaminação; Implantes dentários; Microscopia eletrônica de varredura; Microscopy electron scanning; Osteoblastos; Osteoblasts; Titânio; Titanium
• Link de acesso: http://www.teses.usp.br/teses/disponiveis/25/25146/tde-03092018-175855/

The decontamination process of titanium implants surface is important for the successful treatment of peri-implantitis. The methods of decontamination can be classified in two major groups: chemical or physical. However, the best method of decontamination of implant surfaces is yet undertermined. The aim of this study is to analyze the effectiveness of decontamination of titanium implants surface by chemical conditioning agents and photodynamic therapy, by Scanning Electron Microscopy (SEM) and to analyze the adhesion and proliferation of osteoblastic cells on the previously decontaminated surfaces. Commercially available implants of different brands: Biomet 3i® (Nanotite NT; Osseotite - OT), Straumann® (SLActive SLA) and Neodent® (Acqua Drive CM ACQ; Neoporos Drive CM CM) were acquired in the market and analyzed in SEM images in 3 different areas (n= 1/group) to determine surface roughness parameters and wettability properties. After that, the surface of dental implants was inoculated with Aggregatibacter actinomycetemcomitans (A.a.) strains for 4 days and prepared for SEM analysis to determine the percentage area of contamination in a software for image analysis. Samples were then decontaminated by two different chemical treatments (citric acid 10% and ethylenediamine tetraacetic acid EDTA - 24%) and photodynamic therapy (methylene blue associated with LASER), both with a 3-minutes application time. In the control group, surfaces were decontaminated with chlorhexidine 0.12% for 3 minutes. The area of decontamination was determined in ImageJ software for SEM images analysis. After decontamination, the adhesion and proliferation of human osteoblastic osteosarcoma cell lineage (Saos-2) on the surface of uncontaminated sterile implants (control; n: 1/period) and decontaminated implants (n: 3/period/group) were investigated. Saos-2 cells [5x104] were seeded on implant surfaces and incubated for 24h (adhesion assay) and 72h (proliferation assay), determined on SEM images. No significant differences were found among the different implants regarding roughness parameters, with exception Rv (SLA: 19.57}4.01 vs. OT: 8.36}7.91; p=0.0031). Chemical composition varied among implants depending on surface treatment, with all groups showing prevalence of Titanium. Values showed greater contact angle (wettability analysis) for NT (hydrophobic) and smaller for ACQ (highly hydrophilic) (p<0.0001). Nanotite/Biomet 3i® showed significantly greater percentage of area contaminated by bacteria (68.19% } 8.63%; p=0.050; Kruskal Wallis/Dunn) than ACQ (57.32% } 5.38%). Osseotite/Biomet 3i® resulted in a smaller remaining contaminated area (50.89% } 9.12%) after decontamination treatments. Increased Saos-2 cells adhesion and proliferation were observed on SLA after 24h (p= 0.0006; ANOVA/Tukey) and 72h (<0.001; ANOVA/Tukey). Decontaminated groups showed significantly less number of cells adhered to the surfaces at 24h and 72h than uncontaminated controls (p < 0.005; ANOVA post hoc Sidak). Regarding decontamination methods, no differences in the number of cells attached to implants treated by photodynamic therapy and chemical agents compared to chlorhexidine at 24h, but implants treated by photodynamic therapy and chemical agents showed greater number of cells attached after 72h. These findings suggest that surface characteristics influenced bacterial contamination and decontamination of implant surfaces; none of the decontamination methods were able to completely remove bacterial contamination, impairing cell adhesion and spreading. These findings may explain the varying clinical results of decontamination methods in re-osseointegration.