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Physical, chemical and antimicrobial properties evaluation of a resin based material for braces cementation containing different concentrations of quaternary ammonium

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Mari Miura Sugii
Total Authors: 1
Document type: Master's Dissertation
Press: Piracicaba, SP.
Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
Defense date:
Examining board members:
Flavio Henrique Baggio Aguiar; Anderson Catelan; Flávia Lucisano Botelho do Amaral
Advisor: Flavio Henrique Baggio Aguiar; Ubirajara Pereira Rodrigues Filho

Despite the great need and applicability of orthodontic treatment, most of them include cementation of orthodontic brackets and other metal accessories on tooth surface. Recently, the chemical composition of dental materials has been explored to obtain some specific properties. With regard to composite resins for bonding fixed appliances in orthodontics, antibacterial property is desirable due to cleaning difficulties and biofilm accumulation. Thus the aim of this study was to develop an organosilane with quaternary ammonium group (ORMOSIL-QAMS) and assess chemical and physical properties of Transbond XT Light Cure Adhesive containing 10 wt% and 15 wt% ORMOSIL-QAMS. Furthermore, the study aimed to evaluate its antimicrobial effect incorporated (10 wt% and 15 wt%) to Transbond XT Light Cure Adhesive (3M Unitek) or used as a coating material. A reaction of hydrolysis and condensation (sol-gel) was employed to develop ORMOSIL-QAMS. On the first step, alkoxysilanes containing quaternary ammonium group were obtained. Then a silicate network wrapping the quaternary ammonium was created, leading to the formation of ORMOSIL-QAMS. Synthesis product was characterized by infrared spectroscopy and X-Ray fluorescence. Degree of conversion (DC) (n=7); water sorption (Wsp) (n=9); solubility (Wsl) (n=9); ultimate tensile strength (UTS) (n=10) and shear bond strength (SBS) (n=10) tests were done after 24 h of storage, for the following groups: T ¿ composite resin Transbond XT; T10% - Transbond XT containing 10 wt% of ORMOSIL-QAMS; T15% - Transbond XT containing 15 wt% of ORMOSIL-QAMS. For antibacterial properties one group was added: TC ¿ Transbond XT covered by two layers of ORMOSIL-QAMS. Streptococcus mutans UA159 were grown for 24 h in Brain-Heart-Infusion (BHI) supplemented with 1% sucrose at 37 °C and 5% CO2. Physico-chemical properties data were subjected to ANOVA and Tukey¿s post hoc test (?=0.05). The antibacterial test values were subjected to non-parametric Kruskal-Wallis and Student-Newman-Keuls test (? = 0.05). The DC did not differ between groups (p>0.05). Water sorption and solubility decreased as the percentage of ORMOSIL-QAMS inserted increased (p<0.05). Though, ultimate tensile strength values decreased for both ORMOSIL-QAMS concentrations (p<0.05). Shear bond strength diminished only for T 15% (p<0.05). For antimicrobial test there was no difference between control group and groups where the ORMOSIL-QAMS were added (p>0.05). Only the coating application resulted in less S. mutans biofilm formation in 24 hours (p<0.05). Based on this study it is possible to conclude that incorporating ORMOSIL-QAMS to Transbond XT adversely affected shear bond strength and ultimate tensile strength properties. Additionally, ORMOSIL-QAMS presented the expected antimicrobial activity when applied as coating on the sample surface, diminishing S. mutans biofilm formation considerably (AU)

FAPESP's process: 13/15518-5 - Analysis of the physical and antimicrobial properties of a resin for brackets cimentation with different concentrations of QAMS
Grantee:Mari Miura Sugii
Support Opportunities: Scholarships in Brazil - Master