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Evaluation of surface treatments endurance and antimicrobial activity of organosilane coatings containing quaternary ammonium for stainless steel substrate

Grant number: 16/07809-8
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): September 01, 2016
Effective date (End): April 30, 2017
Field of knowledge:Health Sciences - Dentistry - Dental Clinics
Principal Investigator:Flávio Henrique Baggio Aguiar
Grantee:Mari Miura Sugii
Home Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil


Background and objectives: Orthodontic appliances in the oral cavity favor biofilmaccumulation. To minimize the risk of caries, materials containing functional chemical groupswith antimicrobial effect have been developed. Objectives: 1) Synthesizepolyhydroxyurethanes organosilanes (PHU) by carbon dioxide fixation and an organosilanewith 3- (trimethoxysilyl) propyl methacrylate (TMSPM) containing quaternary ammoniumsalts (ORMOSIL-SiQAI); 2) Check physical, chemical and structural changes in ORMOSILSiQAIby TMSPM replacement for PHU (PHU-SiQAI or TMSPM-SiQAI) or changes inhydrophobic chain SiQAI, (one or two chains that can directly affect the antimicrobialactivity) ; 3) Evaluate brushing resistance, thermal cycling and artificial saliva storageresistance of synthesized compounds applied on stainless steel; 4) Check the antimicrobialeffect of these compounds against the Streptococcus mutans (S. mutans) UA 159 andStreptococcus oralis (S. oralis) ATCC 35037 biofilm formation. Methods: For PHUsynthesis, bis(cyclic carbonate) derived from poly (dimethyl siloxane) (CCPDMS) will besynthesized in an atmosphere of 99.99% CO2. Then the CCPDMS will be reacted with aminesto form the PHU. The PHU-SiQAI and TMSPM-SiQAI will be synthesized by hydrolysis andcondensation reaction (sol-gel). For ORMOSIL-SiQAI synthesis: First, alkoxysilanescontaining quaternary ammonium salts (SiQAI) will be obtained. Then a silicate network iscreated by connecting the alkoxy groups of ORMOSIL and. In this step, TMSPM replacementfor PHU will be performed in order to obtain variations in chemical, physical and biologicalcharacteristics of the final material. The products of synthesis will be characterized byscanning electron microscopy (SEM-EDS); Infrared Spectroscopy (FTIR-ATR); Micro-Raman spectroscopy; nanohardness test and atomic force microscopy (AFM). Thin films willbe formed on stainless steel surfaces. These films will be subjected to brushing cycles,thermal cycling and storage in artificial saliva. The antimicrobial effect of the compounds willbe evaluated before and after surface treatment. Streptococcus mutans (S. mutans) andStreptococcus oralis (S. oralis) biofilm formation assay will be done in Brain Heart Infusion(BHI) with 1 % sucrose for 24 h at 37 °C and CO2 atmosphere (5% to 10% S. mutans and S.oralis). Data will be tabulated and submitted to statistical analysis by a statistical consultant (±=0.05). (AU)