ABSTRACT
OBJECTIVES: This study evaluated the effect of TiO2 nanoparticles + dense hydroxyapatite (HA) on human osteoblast cells (SAOS-2). METHODS: Particulate bovine HA powder with or without the addition of either 5 or 8 % TiO2 (HA, HA/TiO2Np5 % or HA/TiO2Np8 %) were pressed into disks (Ø = 12.5 mm; thickness = 1.3 mm) uniaxially (100 MPa) and isostatically (200 MPa/1 min) and sintered at 1300 °C. Y-TZP disks were used as control. The following tests were performed: Scanning Electron Microscopy and Dispersive Energy Spectroscopy (SEM/EDS), Atomic Force Microscopy (AFM), cell viability assay (Alamar Blue-AB) and mineralized matrix deposition (Alizarin Red-AR). AB and AR data were submitted to 2-way ANOVA/Tukey tests and ANOVA/Tukey tests, respectively. RESULTS: SEM revealed that the surface of HA/TiO2Np5% resembles DPBHA surface, but also contains smaller granules. HA/TiO2Np8% characteristics resembles HA/TiO2Np5% surface, but with irregular topography. Y-TZP showed a typical oxide ceramic surface pattern. EDS revealed Ca, O, and P in all samples. C, O, and Zr appeared in Y-TZP samples. AFM data corroborates SEM analysis. AB test revealed excellent cellular viability for HA/TiO2Np5% group. AR test showed that all groups containing TiO2np had more mineralized matrix deposition than all other groups, with statistically differences between HA/TiO2Np8% and HA cultivated in non-osteogenic medium. Culture in osteogenic medium exhibited much more mineralized matrix deposition by TiO2np groups. SIGNIFICANCE: In conclusion, the addition of TiO2np showed chemical, superficial, and biological changes in the reinforced materials. HA/TiO2Np5% showed the best results for cell viability and HA/TiO2Np8% for mineralized matrix deposition.
Subject(s)
Durapatite , Nanoparticles , Animals , Cattle , Durapatite/chemistry , Durapatite/pharmacology , Humans , Microscopy, Electron, Scanning , Osteoblasts , Oxides/pharmacology , Powders , Surface Properties , Titanium/chemistry , Titanium/pharmacologyABSTRACT
OBJECTIVE: Glass-ionomer cements (GICs) modified with cellulose nanocrystals (CNs) were characterized and evaluated for compressive strength (CS), diametral tensile strength (DTS) and fluoride release (F-). METHODS: Commercially available GICs (Maxxion, Vidrion R, Vitro Molar, Ketac Molar Easy Mix and Fuji Gold Label 9) were reinforced with CNs (0.2% by weight). The microstructure of CNs and of CN-modified GICs were evaluated by transmission electron microscopy (TEM) and by scanning electron microscopy (SEM) while chemical characterization was by Fourier transform infrared spectroscopy (FTIR). Ten specimens each of the unmodified (control) and CN-modified materials (test materials) were prepared for CS and DTS testing. For the fluoride release evaluation, separate specimens (n=10) of each test and control material were made. The results obtained were submitted to the t-test (p<0.05). RESULTS: The CN reinforcement significantly improved the mechanical properties and significantly increased the F- release of all GICs (p<0.05). The GICs with CNs showed a fibrillar aggregate of nanoparticles interspersed in the matrix. The compounds with CNs showed a higher amount of C compared to the controls due to the organic nature of the CNs. It was not possible to identify by FTIR any chemical bond difference in the compounds formed when nanofibers were inserted in the GICs. SIGNIFICANCE: Modification of GICs with CNs appears to produce promising restorative materials.
