RESUMO
Bioactive and biodegradable scaffolds that mimic the natural extracellular matrix of bone serve as temporary structures to guide new bone tissue growth. In this study, 3D-printed scaffolds composed of poly (lactic acid) (PLA)-tricalcium phosphate (TCP) (90-10 wt.%) were modified with 1%, 5%, and 10 wt.% of ZnO to enhance bone tissue regeneration. A commercial chain extender named Joncryl was incorporated alongside ZnO to ensure the printability of the composites. Filaments were manufactured using a twin-screw extruder and subsequently used to print 3D scaffolds via fused filament fabrication (FFF). The scaffolds exhibited a homogeneous distribution of ZnO and TCP particles, a reproducible structure with 300 µm pores, and mechanical properties suitable for bone tissue engineering, with an elastic modulus around 100 MPa. The addition of ZnO resulted in enhanced surface roughness on the scaffolds, particularly for ZnO microparticles, achieving values up to 241 nm. This rougher topography was responsible for enhancing protein adsorption on the scaffolds, with an increase of up to 85% compared to the PLA-TCP matrix. Biological analyses demonstrated that the presence of ZnO promotes mesenchymal stem cell (MSC) proliferation and differentiation into osteoblasts. Alkaline phosphatase (ALP) activity, an important indicator of early osteogenic differentiation, increased up to 29%. The PLA-TCP composite containing 5% ZnO microparticles exhibited an optimized degradation rate and enhanced bioactivity, indicating its promising potential for bone repair applications.
Assuntos
Materiais Biocompatíveis , Regeneração Óssea , Fosfatos de Cálcio , Diferenciação Celular , Proliferação de Células , Células-Tronco Mesenquimais , Osteoblastos , Poliésteres , Impressão Tridimensional , Engenharia Tecidual , Alicerces Teciduais , Óxido de Zinco , Alicerces Teciduais/química , Fosfatos de Cálcio/química , Poliésteres/química , Regeneração Óssea/efeitos dos fármacos , Engenharia Tecidual/métodos , Células-Tronco Mesenquimais/citologia , Óxido de Zinco/química , Materiais Biocompatíveis/química , Diferenciação Celular/efeitos dos fármacos , Osteoblastos/citologia , Osteogênese/efeitos dos fármacos , Teste de Materiais , Osso e Ossos , Regeneração Tecidual Guiada/métodos , Humanos , Animais , Fosfatase Alcalina/metabolismo , Módulo de Elasticidade , Porosidade , Propriedades de SuperfícieRESUMO
OBJECTIVE: The aim of the present study was to compare the in vitro effects of the Er:YAG laser, an ultrasonic system, and manual curette on dentine root surface by roughness and micro-morphological analysis. MATERIALS AND METHODS: Thirty-six flattened bovine roots were randomly assigned to one of the following groups: group 1 (n = 12): Er:YAG laser (2940 nm), 120 mJ/pulse, 10 Hz, 8.4 J/cm2; group 2 (n = 12): ultrasonic system; and group 3 (n = 12): manual curette. The mean surface roughness (Ra) of each sample was measured using a profilometer before and after the treatments. The micro-morphology of the treated and untreated (control) root surfaces was evaluated with scanning electron microscopy (SEM) at 50x and 1000x magnification. RESULTS: Analysis with the profilometer showed that for equal times of instrumentation, the smoothest surfaces were produced by the Er:YAG laser and the ultrasonic system, followed by the curette (p < 0.05). Morphological analyses demonstrated that treatment with the Er:YAG laser produced some areas with an irregular surface, craters, and ablation of the intertubular dentin. The smear layer was removed and dentine tubules were opened by both curettes and the ultrasonic system. The micro-morphology of the dentine root surface after ultrasonic treatment, however, demonstrated randomly distributed areas cratering. CONCLUSION: All instruments increased the roughness of the dentine root surface after treatment; however, the curette produced rougher surfaces than the other devices. SEM analysis revealed distinct root surface profiles produced by the three devices.
Assuntos
Curetagem/instrumentação , Raspagem Dentária/instrumentação , Dentina/efeitos da radiação , Lasers de Estado Sólido , Raiz Dentária/efeitos da radiação , Terapia por Ultrassom/instrumentação , Animais , Bovinos , Dentina/cirurgia , Dentina/ultraestrutura , Propriedades de Superfície/efeitos da radiação , Técnicas de Cultura de Tecidos , Raiz Dentária/cirurgia , Raiz Dentária/ultraestruturaRESUMO
Ratos Wistar machos, com 30 dias de idade, foram submetidos a intoxicacao experimental, com 100 ppm de HgCl2, por via oral.Os niveis de lipoperoxidacao hepatica e renal foram avaliados, medindo-se a quantidade total de malonildialdeido (MDA) produzido por homogenados desses orgaos. Nao se obteve nenhuma alteracao na quantidade de MDA produzida pelos homogenados. Cortes histologicos desses orgaos, nos animais tratados, nao mostraram alteracoes, quando comparados com os do grupo controle