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Compostos contendo amônio quaternário para prevenção da formação de biofilme oral

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Mari Miura Sugii
Total Authors: 1
Document type: Doctoral Thesis
Press: Piracicaba, SP.
Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
Defense date:
Examining board members:
Flavio Henrique Baggio Aguiar; Brandon Peterson; Lourenço Correr Sobrinho; Lucas Wilhelm Maria Van der Sluis; Maria Magdalena Gerd Kempermann; Marco Markus Maria Gresnigt; Klaus Heinz Rischka
Advisor: Ubirajara Pereira Rodrigues Filho; Prashant Kumar Sharma; Flavio Henrique Baggio Aguiar

Background and objectives: Orthodontic appliances in the oral cavity favor biofilm accumulation. To minimize the negative impact of biofilm formation, coatings with antimicrobial effect have been developed. This thesis aims to present: 1) A literature review about quaternary ammonium compounds (QAC), its diverse applications and the variables influencing the antimicrobial activity of these compounds; 2.1) An in vitro study with development, synthesis and characterization of a quaternary ammonium salt (QAS) coupled to different polyhydroxyurethanes (PHU and PHU*) for stainless steel coating (PHU-QAS and PHU*QAS); 2.2) evaluate the antimicrobial activity of the coatings¿ surface and leachate against Streptococcus mutans (S. mutans); 2.3) evaluate the cytotoxicity of coatings¿ leachate over fibroblasts L929 and 2.4) evaluate the effect of washing in demineralized water or ion-exchange in sodium phosphate solution on cytotoxicity. Both coatings showed contact-killing and planktonic antimicrobial activity against cariogenic S. mutans up to 7 days tested. Both ion exchange and washing in demineralized water changed the coating nanostructure without diminishing antimicrobial efficiency. Detached QAS from the PHU and PHU* backbone leached out of the coating to give rise to planktonic antimicrobial activity and cytotoxicity. PHU-QAS coating when washed in demineralized water is suitable for orthodontic application aiming biofilm prevention. The literature review included 107 citations about the use of QAC in different fields and was divided in 9 topics: Background; biofilm treatment and prevention; quaternary ammonium compounds and their chemistry; cationic acrylates and cationic silanes; QAC disinfectants and preservatives; in situ quaternization of tertiary amines to form QAC and nanoparticles functionalization; variables influencing antimicrobial properties of QAC; cytotoxicity and antimicrobial resistance. In the in vitro study, a QAS with an alkyl chain of 12 carbons was coupled to PHU or PHU* originating PHU-QAS and PHU*-QAS compounds that were used to coat stainless steel. Compounds were characterized by infrared spectroscopy, nuclear magnetic resonance, X-ray photoelectron spectroscopy and grazing incidence scatteing X-ray. The antimicrobial effect was evaluated in two time points with planktonic S. mutans for the coatings¿ surface and leachate. The cytotoxicity of coatings¿ leachate was evaluated with fibroblasts L929. Two surface treatments were tested to diminish the cytotoxicity: washing in demineralized water for 3 days or ion-exchange in sodium phosphate solution for 2 h. All coatings presented antimicrobial activity for S. mutans on both time points tested. Washing in demineralized water was able to diminish the cytotoxicity of PHU-QAS on the second time point tested. Ion-exchange though promoted chemical and nanostructural changes but was not able to diminish cytotoxicity. It was concluded that PHU-QAS and PHU*QAS presented effective antimicrobial activity against S. mutans. Surface treatments did not diminish the antimicrobial activity of the coatings. PHU-QAS coatings after washing can be considered suitable for biofilm prevention over stainless steel devices (AU)

FAPESP's process: 16/07809-8 - Evaluation of surface treatments endurance and antimicrobial activity of organosilane coatings containing quaternary ammonium for stainless steel substrate
Grantee:Mari Miura Sugii
Support type: Scholarships in Brazil - Doctorate