FREIRE, W. P.; http://lattes.cnpq.br/0858443814426502; FREIRE, Waldênia Pereira.
Résumé:
The Glass Ionomer Cements (GICs) are widely used materials in dentistry have fluoride release, chemical adhesion to the substrate and dental thermal expansion similar to tooth structure. The limitation of their use is given by its low mechanical strength compared with other restorative materials. In order to improve the biomechanical properties of these materials it is proposed the inclusion of bioactive particles, such as calcium phosphate bioceramics. Hydroxyapatite (HA, Ca10(PO4)6(OH)2), is a type of calcium phosphate widely used for biological purposes for their similarity to the mineral phase of bones and teeth, and has excellent chemical affinity with these biological tissues. Thus, the aim of this work was the development of experimental glass ionomer cement and evaluating the effect of incorporation of HA this material in different proportions (5% to 12% by weight) comparative analysis of physico-chemical, mechanical and biological GIC against a commercial (control group).To propose the experimental cement was performed a mixing of the reactants (SiO2, Al2O3, CaF2, AlF3, AlPO4), and the liquid part was obtained with an polyacid solution (C3H4O2, C4H6O6; H2CCH2C (= CH2) CO2H), with reference to the composition mentioned GICs in the literature; as a control group was used GIC Vidrion R (SS WHITE). After obtaining the experimental cement characterizations were conducted by the techniques: X-ray diffraction (XRD), Infrared Spectroscopy Fourier Transform (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy X-ray (EDX), Wettability by contact angle and Evaluation of cell viability of macrophages. Mechanical testing of hardness, flexural strength and strength compression were also conducted. The results of this study indicate that: the X-ray diffraction experimental cement showed an increase in crystallinity compared to the control group, but with reduced crystallinity with the addition of 5% of HA. In the FTIR spectra was observed that the addition of HA in experimental cement does not significantly alter the chemical profile characteristic of this material. The microstructure of the cement experimental study showed that there was no proper interaction particle / polymer matrix, and including different proportions of HA did not affect the microstructure of the composites analyzed. When measuring wettability by contact angle, experimental cements showed higher wetting ability. In the assessment of cell viability of all cements examined were considered non-cytotoxic and the inclusion of HA did not alter the response of these cell materiaI. In the mechanical tests, the experimental cement showed higher hardness compared to the control group, but the inclusion of HA did not cause a significant effect in this material. The flexural strength of the experimental cement increased with the addition of hydroxyapatite; so as when testing the compressive strength, the cement experimental exhibited the highest modulus of elasticity among materials analyzed, consisting of an alternative of a restorative biomaterial with properties suitable for dentistry.
