RESUMO
Although Ultrananocrystalline diamond (UNCD) has been proposed as a coating material for titanium biomedical implants, the biological effects and toxicity of UNCD particles that could eventually detach have not been studied to date. The biokinetics and biological effects of UNCD compared to titanium dioxide (TiO2 ) nanoparticles was evaluated in vivo using Wistar rats (n = 30) i.p. injected with TiO2 , UNCD or saline solution. After 6 months, blood, lung, liver, and kidney samples were histologically analyzed. Oxidative damage by membrane lipidperoxidation (thiobarbituric acid reactive substances-TBARS), generation of reactive oxygen species (superoxide anion- O2-), and antioxidant enzymes (superoxide dismutase-SOD, catalase-CAT) was evaluated in lung and liver. Histologic observation showed agglomerates of TiO2 or UNCD in the parenchyma of the studied organs, though there were fewer UNCD than TiO2 deposits. In addition, TiO2 caused areas compatibles with foci of necrosis in the liver and renal hyaline cylinders. Regarding UNCD, no membrane damage (TBARS) or mobilization of enzymatic antioxidants was observed either in lung or liver samples. No variations in O2- generation were observed in lung (Co: 35.1 ± 4.02 vs. UNCD: 48 ± 9.1, p > 0.05). Conversely, TiO2 exposure caused production of O2- in alveolar macrophages and consumption of catalase (p < 0.05). The studied parameters suggest that UNCD caused neither biochemical nor histological alterations, and therefore may prove useful as a surface coating for biomedical implants. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2408-2415, 2017.
Assuntos
Materiais Revestidos Biocompatíveis , Teste de Materiais , Nanodiamantes , Titânio , Animais , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacocinética , Materiais Revestidos Biocompatíveis/farmacologia , Masculino , Nanodiamantes/química , Nanodiamantes/uso terapêutico , Especificidade de Órgãos/efeitos dos fármacos , Ratos , Ratos Wistar , Titânio/química , Titânio/farmacocinética , Titânio/farmacologiaRESUMO
The aim of this experimental work was to evaluate deposition of titanium dioxide (TiO2 ) microparticles and nanoparticles, which could originate from titanium bioimplants, in the gingiva. Wistar rats were injected intraperitoneally (i.p.) with a suspension of TiO2 particles of different sizes (150, 10, or 5 nm). The rats were killed 12 months post-injection, and the buccal and lingual gingivae were resected and evaluated using light and scanning electron microscopy. Energy-dispersive X-ray spectroscopy (EDS) was used to confirm the presence of titanium in deposits of microparticles and nanoparticles, and the concentration of titanium in tissues was measured using inductively coupled plasma-mass spectrometry (ICP-MS). Histological examination showed that all experimental groups exhibited agglomerates, in the gingiva, of titanium particles of micrometer size range, with no associated inflammatory response. Higher concentrations of titanium traces were shown, by ICP-MS, in both buccal and lingual tissues of all experimental groups compared with their matched controls. Titanium concentrations were significantly higher in the buccal gingiva than in the lingual gingiva, and after injection with 5-nm particles than with 10-nm particles in both localizations. Titanium microparticles and nanoparticles deposit in the gingiva, and mostly on the buccal side. Gingival deposition of titanium could be considered a tissue indicator of tribocorrosion processes of titanium bioimplants.
Assuntos
Materiais Biocompatíveis/metabolismo , Gengiva/metabolismo , Titânio/farmacocinética , Animais , Materiais Biocompatíveis/química , Epitélio/metabolismo , Epitélio/ultraestrutura , Gengiva/ultraestrutura , Injeções Intraperitoneais , Masculino , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/química , Microscopia Eletrônica de Varredura/métodos , Tamanho da Partícula , Ratos , Ratos Wistar , Espectrometria por Raios X/métodos , Espectrofotometria Atômica/métodos , Espectrometria de Massas em Tandem/métodos , Fatores de Tempo , Distribuição Tecidual , Titânio/administração & dosagem , Titânio/químicaRESUMO
The layer of titanium dioxide (TiO(2)) of the implant is chronically exposed to the internal electrolyte milieu in the peri-implant biological compartment. Corrosion results from electrochemical attack and ensuing gradual degradation of the metallic materials and is thus of biological interest when these biomaterials are employed in clinical implantology. Herein we evaluated and compared the chronic effect and the biodistribution of TiO(2) administered subcutaneously or intraperitoneally. We propose that the compartmentalization of titanium in the area of subcutaneous injection would reproduce the biological compartment of the implant and its microenvironment from which metal ions could be released and migrate systemically. Potential TiO(2) deposits were identified and characterized in skin, liver and lung by histological and EDX analyses. After both treatments, the skin, liver, and lungs exhibited histological evidence of TiO(2) deposits. In order to characterize in situ macrophage-like cells, tissue sections were immunohistochemically stained for CD68. Tissue specimens from all organs assayed showed positive staining for anti-macrophage monoclonal antibody CD68 (PGM1). Despite the compartmentalization of titanium within nodular areas in rats treated subcutaneously, systemic migration occurred. We concluded that systemic migration of TiO(2) occurred regardless of the administration route.
Assuntos
Materiais Biocompatíveis/farmacocinética , Titânio/farmacocinética , Animais , Antígenos CD/biossíntese , Antígenos de Diferenciação Mielomonocítica/biossíntese , Materiais Biocompatíveis/química , Corrosão , Eletroquímica/métodos , Íons , Fígado/metabolismo , Pulmão/metabolismo , Macrófagos/metabolismo , Masculino , Ratos , Ratos Wistar , Pele/metabolismo , Distribuição Tecidual , Titânio/químicaRESUMO
The TiF4 application produces a titanium coating on enamel surface, reducing solubility in presence of cariogenic challenge. However, it is not established if this titanium also penetrates inside the enamel. The aim of this study was to evaluate in vitro the presence of this superficial coat and titanium penetration into human sound and decayed enamel after TiF4 application. Twenty-four unerupted third molars were mesiodistally cut and divided into two groups (GA--sound and GB--artificial decayed). After a 4% TiF4 application, each sample was fractured longitudinally (occlusal-cervical). Through microprobe analysis with energy dispersive spectrometer (EDS), titanium penetration could be observed inside the enamel. The McNemar test (p=0.267) showed that there was no difference between the groups analyzed regarding to titanium penetration, although in group A the titanium penetrated more deeply (Wilcoxon test, p=0.047). It could be concluded that there was no difference between the groups regarding the titanium penetration, but titanium penetrated more deeply into sound enamel compared to artificially decayed enamel.