Influence of zirconia-coated bioactive glass on gingival fibroblast behavior

Abstract The objective of this study was the development of a bioactive glass coating on zirconia (Zr) to modulate the gingival fibroblast phenotype. For this purpose, Biosilicate® (BS) particles in a water/isopropyl alcohol (1:1) vehicle (6 mg/mL) were applied to zirconia discs followed by thermal treatment at 1100 °C for 20 min. The surface topography (SEM), chemical composition (EDX), surface roughness (Ra; confocal microscopy), surface free energy (goniometry), and color alteration (UV-vis spectrophotometry) were assessed (n=6). Thereafter, L929 fibroblasts were seeded onto Zr and Zr+BS discs, and cell proliferation (Alamar Blue; n=6), morphology (SEM; n=2), migration (wound healing; n=4), and collagen synthesis (Sirius Red; n=6) were evaluated up to 7 days. Data were analyzed by ANOVA/Tukey tests (a=5%). A homogeneous coating consisting of Si, Na, O, and Ca was detected on the Zr surface after thermal treatment with BS, which led to a significant increase in surface roughness and free energy (p<0.05). No change in color parameters was observed (p>0.05). Cells seeded on the Zr+BS surface featured increased proliferation, collagen expression, and migration capability in comparison with those cultured on plain Zr (p<0.05). SEM images revealed that cell spreading occurred faster in the presence of BS. Therefore, it was concluded that thermal treatment of the Zr surface with BS led to the deposition of a bioactive coating, which induced gingival fibroblast spread, proliferation, migration, and collagen expression in vitro.

Resumo O objetivo deste estudo foi o desenvolvimento de um recobrimento de vidro bioativo sobre a zircônia (Zr) para modular o fenótipo de fibroblastos gengivais. Para este propósito, partículas de Biosilicato® (6 mg/mL) em um veículo a base de água/álcool isopropílico (1:1) foram aplicadas sobre discos de zircônia seguido por tratamento térmico a 1100 °C por 20 min. A topografia de superfície (MEV), composição química (EDX), rugosidade de supefície (Ra; microscopia confocal), energia livre de superfície (goniômetro) e alteração de cor (Espectrofotometria UV-vis) foram avaliadas (n=6). A seguir, fibroblastos L929 foram semeados sobre discos de Zr e BS+Zr e a proliferação (Alamar Blue; n=6), morfologia (MEV; n=2), migração celular (wound healing; n=4) e a síntese de colágeno (Sirius Red; n=6) foram avaliados até 7 dias. Os dados foram analisados pelos testes ANOVA/Tukey (a=5%). Um recobrimento homogêneo consistindo de Si, Na, O e Ca foi detectado na superfície da Zr após o tratamento térmico com BS, o qual promoveu um aumento significante na rugosidade e energia livre de superfície (p<0,05). Nenhuma mudança nos parâmetros de cor foi observada (p>0,05). Células semeadas na superfície de Zr+BS apresentaram maior proliferação, expressão de colágeno e capacidade de migração em comparação com aquelas cultivadas sobre a superfície de Zr (p<0,05). Imagens de MEV revelaram que o espalhamento celular ocorreu mais rápido na presença de BS. Assim, conclui-se que o tratamento térmico da superfície da Zr com BS levou a deposição de um recobrimento bioativo, o qual induziu in vitro o espalhamento, proliferação e migração de fibroblastos gengivais e expressão de colágeno.

Osteoblastic behavior to zirconium coating on Ti-6Al-4V alloy

PURPOSE: The purpose of this study was to assess the surface characteristics and the biocompatibility of zirconium (Zr) coating on Ti-6Al-4V alloy surface by radio frequency (RF) magnetron sputtering method. MATERIALS AND METHODS: The zirconium films were developed on Ti-6Al-4V discs using RF magnetron sputtering method. Surface profile, surface composition, surface roughness and surface energy were evaluated. Electrochemical test was performed to evaluate the corrosion behavior. Cell proliferation, alkaline phosphatase (ALP) activity and gene expression of mineralized matrix markers were measured. RESULTS: SEM and EDS analysis showed that zirconium deposition was performed successfully on Ti-6Al-4V alloy substrate. Ti-6Al-4V group and Zr-coating group showed no significant difference in surface roughness (P>.05). Surface energy was significantly higher in Zr-coating group than in Ti-6Al-4V group (P<.05). No difference in cell morphology was observed between Ti-6Al-4V group and Zr-coating group. Cell proliferation was higher in Zr-coating group than Ti-6Al-4V group at 1, 3 and 5 days (P<.05). Zr-coating group showed higher ALP activity level than Ti-6Al-4V group (P<.05). The mRNA expressions of bone sialoprotein (BSP) and osteocalcin (OCN) on Zr-coating group increased approximately 1.2-fold and 2.1-fold respectively, compared to that of Ti-6Al-4V group. CONCLUSION: These results suggest that zirconium coating on Ti-6Al-4V alloy could enhance the early osteoblast responses. This property could make non-toxic metal coatings on Ti-6Al-4V alloy suitable for orthopedic and dental implants.

Effect of magnesium and calcium phosphate coatings on osteoblastic responses to the titanium surface

PURPOSE: The aim of this study was to evaluate the surface properties and in vitro bioactivity to osteoblasts of magnesium and magnesium-hydroxyapatite coated titanium. MATERIALS AND METHODS: Themagnesium (Mg) and magnesium-hydroxyapatite (Mg-HA) coatings on titanium (Ti) substrates were prepared by radio frequency (RF) and direct current (DC) magnetron sputtering.The samples were divided into non-coated smooth Ti (Ti-S group), Mg coatinggroup (Ti-Mg group), and Mg-HA coating group (Ti-MgHA group).The surface properties were evaluated using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The surface roughness was evaluated by atomic force microscopy (AFM). Cell adhesion, cell proliferation and alkaline phosphatase (ALP) activity were evaluated using MC3T3-E1 cells. Reverse transcription polymerase chain reaction (RT-PCR) analysis was performed. RESULTS: Cross-sectional SEM images showed that Mg and Mg-HA depositionson titanium substrates were performed successfully. The surface roughness appeared to be similaramong the three groups. Ti-MgHA and Ti-Mg group had improved cellular responses with regard to the proliferation, alkaline phosphatase (ALP) activity, and bone-associated markers, such as bone sialoprotein (BSP) and osteocalcin (OCN) mRNA compared to those of Ti-S group. However, the differences between Ti-Mg group and Ti-MgHA group were not significant, in spite of the tendency of higher proliferation, ALP activity and BSP expression in Ti-MgHA group. CONCLUSION: Mg and Mg-HAcoatings could stimulate the differentiation into osteoblastic MC3T3-E1 cells, potentially contributing to rapid osseointegration.

Antimicrobial surfaces for craniofacial implants: state of the art

In an attempt to regain function and aesthetics in the craniofacial region, different biomaterials, including titanium, hydroxyapatite, biodegradable polymers and composites, have been widely used as a result of the loss of craniofacial bone. Although these materials presented favorable success rates, osseointegration and antibacterial properties are often hard to achieve. Although bone-implant interactions are highly dependent on the implant's surface characteristics, infections following traumatic craniofacial injuries are common. As such, poor osseointegration and infections are two of the many causes of implant failure. Further, as increasingly complex dental repairs are attempted, the likelihood of infection in these implants has also been on the rise. For these reasons, the treatment of craniofacial bone defects and dental repairs for long-term success remains a challenge. Various approaches to reduce the rate of infection and improve osseointegration have been investigated. Furthermore, recent and planned tissue engineering developments are aimed at improving the implants' physical and biological properties by improving their surfaces in order to develop craniofacial bone substitutes that will restore, maintain and improve tissue function. In this review, the commonly used biomaterials for craniofacial bone restoration and dental repair, as well as surface modification techniques, antibacterial surfaces and coatings are discussed.