Newly strategies to enhance titanium surface properties and to control biofilm-related peri-implant infections

Author(s)

Raphael Cavalcante Costa

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2020-02-28

Examining board members

Valentim Adelino Ricardo Barão; Cinthia Pereira Machado Tabchoury; Carolina Patrícia Aires

• Advisor: Valentim Adelino Ricardo Barão

Abstract

The decreases osseointegration at the bone/implant interface and peri-implant infections are the main causes related to failures in rehabilitation with titanium (Ti) based dental implants. Considering these etiological factors, therapeutic strategies have been developed recently aiming to increase the success rates of implant rehabilitation. Among these approaches, surface treatments have a promising role for biomedical applications due to the ability to able the Ti surface more bioactive and improve the osseointegration. Thus, (1) the first study aimed to develop a surface treatment (PEO-BG) based on 45S5-bioglass (45% SiO2, 245% CaO, 24.5% NaO and 6% P2O5) using plasma electrolytic oxidation (PEO) as a new route for incorporation on Ti. The surface, mechanical, tribological, electrochemical, microbiological and biological properties were evaluated. The newly developed PEO-BG showed high roughness and surface area determining a complex surface topography, super-hydrophilic status, chemical composition and oxide layer mimetic to the 45S5-BG. Experimental coating improved the mechanical and tribological properties (p<0.05) and enhanced the corrosion resistance after simulated in vitro degradation (28 days) (p<0.05). The PEO-BG coating was also able to modulate microbial adhesion (2 h) and the formation of oral biofilm (24 h), changing the bacterial profile and reducing the pathogenic potential (p<0.05). Furthermore, developed coating can be considered bioactive due to hydroxyapatite-inducing ability with progressive release of bioactive ions and increase of pH. In addition, PEO-BG favored greater adsorption of plasma proteins from human blood without presenting toxicity to fibroblasts, which suggests promising biological effects in vivo. Another relevant point is that implant surfaces are also susceptible to the chronic accumulation of microorganisms immersed in biofilm extracellular matrix (ME). ME acts as a protective barrier and to able it difficult to control biofilm and peri-implant infections treatment. Then, (2) the secondy study evaluated the role of ECM in the pathogenicity of oral biofilm and resistance against antimicrobials on Ti surface using an in vitro model that simulates the transition process to peri-implantitis (from supragingival to subgingival biofilm). Additionally, a dual-targeting therapeutic approach was tested using an emerging matrix disrupting agent (iodo povidone) in biofilms formed in situ in the oral environment. ECM biofilm leads to oral biofilm dysbiosis, increasing virulence and damage to host cells (p<0.05). In addition, ECM biofilm also increased the antimicrobial resistance of Ti surface biofilms (p<0.05). Hence, dual-targeting therapeutic approach reduced oral biofilm formation enhanced the efficacy of peri-implant targeted antimicrobials (p<0.05). In conclusion, bioactive surface treatments such as the newly developed PEO-BG coating, which improves the surface properties of Ti aiming to enhance osseointegration and increase the longevity of treatments with dental implants as well as the recent combined strategy for ECM degradation is an effective and promising strategy for biofilm control and non-surgical treatment of peri-implantitis (AU)

• FAPESP's process: 18/04630-2 - Synthesis of bioactive glass coating for titanium surface using the plasma electrolytic oxidation: electrochemical and antimicrobial analysis in a microcosm model
• Grantee: Raphael Cavalcante Costa
• Support Opportunities: Scholarships in Brazil - Master