Osseointegration of two different phosphate ion-containing titanium oxide surfaces in rabbit cancellous bone

Surface characteristics and in vitro biocompatibility of surface-modified titanium foils as a regenerative barrier membrane for guided bone regeneration

This study evaluated surface characteristics and biocompatibility of surface-modified thin titanium (Ti) foils as a regenerative barrier membrane for future application in guided bone regeneration (GBR) surgery to augment atrophic alveolar bone. Anodic oxidation and post-heat treatment were performed to prepare various Ti foil samples. Then, the in vitro soft and hard tissue compatibility of the samples was evaluated by examining the cell responses using primary human gingival fibroblasts (HGFs) and MG63 human osteoblast-like cells. Investigated Ti foil samples showed marked differences in physicochemical surface properties. Additional 400°C heat treatment applied to the anodized Ti surface led to formation of an anatase titanium dioxide structure and well-organized nanoscale protrusions, and significantly increased surface wettability. Anodization and heat treatment enhanced the growth of HGFs and MG63 cells in Ti foil samples. Additional heat treatment for 10 and 30 min further significantly improved the response of HGFs including spreading and proliferation, and upregulated the mRNA expression of cell adhesion- and maturation-related genes as well as the osteoblast differentiation of MG63 cells. Ti foil sample with thin oxide coating obtained by a 30 min heat treatment exhibited poor clinical plasticity as a regenerative barrier membrane, which showed complete coating failure in the bending test. Our results indicate that anatase Ti oxide coating of a specific film thickness with nanoscale surface protrusion morphology and hydrophilic characteristics obtained by anodization and post-heat treatment would be an effective approach as a biocompatible Ti regenerative membrane for inducing better regeneration of both gingival tissue and bone.

Mg/Cu-doped TiO2 nanotube array: A novel dual-function system with self-antibacterial activity and excellent cell compatibility

Many studies were conducted to change the surface morphology and chemical composition of Ti implants for the improvement of antibacterial ability and osseointegration between medical Ti and surrounding bone tissue. In this study, we successfully prepared a novel dual-function coating on pure Ti surface, i.e. Cu and Mg-co-doped TiO₂ nanotube (TN) coating, by combining anodisation and hydrothermal treatment (HT), which could act as a delivery platform for the sustained release of Cu and Mg ions. Results showed that the amounts of Cu and Mg were about 5.43 wt%-6.55 wt% and 0.69 wt%-0.73 wt%, respectively. In addition, the surface morphology of Cu and Mg-co-doped TN (CuMTN) coatings transformed into nanoneedles after HT for 1 h. Compared with TN, CuMTN had no change in roughness and remarkable improved hydrophilicity. Antibacterial tests revealed that CuMTN had an antibacterial rate of more than 93% against Escherichia coli and Staphylococcus aureus, thereby showing excellent antibacterial properties. In addition, CuMTN could induce the formation of apatite well after being immersed in simulated body fluid, showing good biological activity. Preosteoblasts (MC3T3-E1) cultured on CuMTN-coated Ti demonstrated better proliferation and osteogenic differentiation than pristine and as-anodised specimens. To the best of our best knowledge, this study had successfully attempted to combine anodisation and HT, introduce Cu/Mg elements and functionalise Ti-based implant surfaces with enhanced hydrophilicity, osteogenesis and antimicrobial properties that can meet clinical needs for the first time.

MgCl2 promotes mouse mesenchymal stem cell osteogenic differentiation by activating the p38/Osx/Runx2 signaling pathway

Magnesium, an important inorganic mineral component in bones, enhances osteoblast adhesion and osteogenic gene expression. Mg2+‑containing hydroxyapatite promotes mouse mesenchymal stem cell (MMSC) osteogenic differentiation. In the present study, MMSCs were cultured in media containing different concentrations of MgCl2 (0 and 20 mM) for different time periods. Western blotting and reverse transcription‑quantitative PCR were performed to determine the expression levels of phosphorylated (p)‑p38 mitogen‑activated protein kinase (MAPK), the osteoblast‑specific transcription factor Osterix (Osx), runt‑related transcription factor 2 (Runx2), and p38 downstream genes, such as 27 kDa heat shock protein (hsp27), activating transcription factor 4 (Atf4), myocyte enhancer factor 2C (Mef2c) and CCAAT/enhancer‑binding protein homologous protein (Ddit3). The facilitatory effect of MgCl2 on MMSC osteogenic differentiation was assessed via Alizarin Red staining. The results suggested that MgCl2 increased p38 phosphorylation compared with the control group. Downstream genes of the p38 signaling pathway, including Osx and Runx2, as well as several osteogenesis‑associated downstream target genes, including Hsp27, Atf4, Ddit3 and Mef2c, were significantly upregulated in the Mg2+‑treated group compared with the control group. The increased osteogenic differentiation in the Mg2+‑treated group was significantly attenuated in MMSCs treated with SB203580, a specific inhibitor of the p38 signaling pathway. The results suggested that appropriate concentrations of MgCl2 promoted MMSC osteogenic differentiation via regulation of the p38/Osx/Runx2 signaling pathway.

The effects of metformin on the bone filling ration around of TiAl6Va4 implants in non diabetic rats

Objectives

In this research it was aimed to that evaluation of the effects of systemic metformin administration on the periimplant bone tissue response of TiAl₆Va₄ implants in experimental rat model.

Materials and method

Firstly TiAl₆Va₄ implants were inserted surgically in the metaphyseal part of the tibial bone and after, the rats were randomly separated into two groups: Controls (CNT) (n = 10) and Metformin group (M) (n = 10). No additional treatment was applied to the controls during the 4-week experimental period. Rats received 40 mg/kg metformin in every day during the four week experimental period in M group. At the end of the 28-day follow-up period, the TiAl₆Va₄ implants with surrounding bone were used for the histopathologic analysis. To analysis of the datas between M and CNT Student-T Test was used.

Result

Periimplant bone tissue filling ratios (%) were detected higher in M group compared with the CNT (P < 0.05).

Conclusion

Systemic administration of metformin may increases titanium implant osseointegration in non-diabetic rats.

Enhanced Bone Remodeling Effects of Low-Modulus Ti-5Zr-3Sn-5Mo-25Nb Alloy Implanted in the Mandible of Beagle Dogs under Delayed Loading

Titanium (Ti) and its alloys are widely used in the dental and prosthetic implant fields due to their favorable biocompatibility. In this study, porous surface coatings incorporated with nanoscale hydroxyapatite particles on the surface of Ti and Ti-5Zr-3Sn-5Mo-25Nb (TLM) alloy were fabricated by microarc oxidation followed by hydrothermal treatment; the surface roughness and hydrophilicity were obviously enhanced by the surface modification procedure. In vivo, four adult male beagle dogs were selected for an implantation procedure and restored with full metal crowns after healing for 3 months. The bone responses were evaluated via histomorphological observation. Raman spectral analysis and nanoindentation experiments were used to quantitatively and qualitatively estimate the characteristics of the bone formed around the implants. Compared to the Ti group, the TLM titanium alloy group showed a significant increase in the percentage of bone-implant interface contact, bone inside the thread, mineralization, crystallinity, modulus of elasticity, and hardness of the integrated bone after delayed loading in the TLM group. Therefore, the TLM titanium alloy is considered a candidate implant material with desirable biomechanical compatibility, especially under applied stress.

Influence of Titanium Oxide Pillar Array Nanometric Structures and Ultraviolet Irradiation on the Properties of the Surface of Dental Implants-A Pilot Study

Aim: Titanium implants are commonly used as replacement therapy for lost teeth and much current research is focusing on the improvement of the chemical and physical properties of their surfaces in order to improve the osseointegration process. TiO₂, when it is deposited in the form of pillar array nanometric structures, has photocatalytic properties and wet surface control, which, together with UV irradiation, provide it with superhydrophilic surfaces, which may be of interest for improving cell adhesion on the peri-implant surface. In this article, we address the influence of this type of surface treatment on type IV and type V titanium discs on their surface energy and cell growth on them. Materials and methods: Samples from titanium rods used for making dental implants were used. There were two types of samples: grade IV and grade V. In turn, within each grade, two types of samples were differentiated: untreated and treated with sand blasting and subjected to double acid etching. Synthesis of the film consisting of titanium oxide pillar array structures was carried out using plasma-enhanced chemical vapor deposition equipment. The plasma was generated in a quartz vessel by an external SLAN-1 microwave source with a frequency of 2.45 GHz. Five specimens from each group were used (40 discs in total). On the surfaces to be studied, the following determinations were carried out: (a) X-ray photoelectron spectroscopy, (b) scanning electron microscopy, (c) energy dispersive X-ray spectroscopy, (d) profilometry, (e) contact angle measurement or surface wettability, (f) progression of contact angle on applying ultraviolet irradiation, and (g) a biocompatibility test and cytotoxicity with cell cultures. Results: The application of ultraviolet light decreased the hydrophobicity of all the surfaces studied, although it did so to a greater extent on the surfaces with the studied modification applied, this being more evident in samples manufactured in grade V titanium. In samples made in grade IV titanium, this difference was less evident, and even in the sample manufactured with grade IV and SLA treatment, the application of the nanometric modification of the surface made the surface optically less active. Regarding cell growth, all the surfaces studied, grouped in relation to the presence or not of the nanometric treatment, showed similar growth. Conclusions. Treatment of titanium oxide surfaces with ultraviolet irradiation made them change temporarily into superhydrophilic ones, which confirms that their biocompatibility could be improved in this way, or at least be maintained.

The relative effects of Ca and Mg ions on MSC osteogenesis in the surface modification of microrough Ti implants

Purpose

Calcium (Ca) and magnesium (Mg) ions have been used as promising bioactive ions in the surface chemistry modification of titanium (Ti) bone implants to increase bone regeneration capacity. However, it is not clear which (Ca or Mg) plays the more important role in the early osteogenic differentiation of mesenchymal stem cells (MSCs) when applied to the surface of commercially available microstructured Ti implants. This study investigated the relative effect of these two ions on the early osteogenic functionality of primary mouse bone marrow MSCs in order to obtain insights into the surface design of Ti implants with enhanced early osteogenic capacity.

Methods and results

Wet chemical treatment was performed to modify a microrough Ti implant surface using Ca or Mg ions. Both the Ca and Mg-incorporated surfaces accelerated early cellular events and the subsequent osteogenic differentiation of MSCs compared with an unmodified microrough Ti surface. Surface Mg modification exhibited a more potent osteoblast differentiation-promoting effect than the Ca modification. Surface Mg incorporation markedly inhibited the phosphorylation of β-catenin.

Conclusion

These results indicate that alteration of the surface chemistry of microstructured Ti implants by wet chemical treatment with Mg ions exerts a more effect on promoting the early osteogenic differentiation of MSCs than Ca ions by enhancing early cellular functions, including focal adhesion development and stabilization of intracellular β-catenin.

Osteogenic differentiation of mesenchymal stem cells modulated by a chemically modified super-hydrophilic titanium implant surface

This study investigated the osteogenic functionality of multipotent mesenchymal stem cells (MSCs) modulated by a chemically modified super-hydrophilic titanium (Ti) bone implant surface to elucidate the biological mechanism underlying the bone healing capacity of this modified Ti surface. A microstructured Ti surface incorporating bioactive ions (in this study, phosphate (P) ions) was prepared by wet chemical treatment. The results showed that the hydrothermally obtained crystalline P-incorporated Ti surface (P surface) displayed long-term super-hydrophilicity (water contact angles <5°) during a 36-week observation period. The hydrophilic P surface enhanced early cellular functions and osteogenic differentiation of multipotent MSCs derived from mouse bone marrow and human adipose tissue. The expression of critical integrins affecting subsequent osteoblast function and osteoblast phenotype genes was notably upregulated in multipotent MSCs grown on the P surface compared with the commercially available grit-blasted microrough clinical oral implant surface. The P surface supported better cell spreading, focal adhesion and ALP activity of MSCs. These results indicate that a super-hydrophilic P-incorporated Ti surface accelerates implant bone healing by enhancing the early osteogenesis functions of multipotent MSCs.

Early osseointegration of implants with cortex-like TiO2 coatings formed by micro-arc oxidation: A histomorphometric study in rabbits

In our previous studies, a novel cortex-like TiO₂ coating was prepared on Ti surface through micro-arc oxidation (MAO) by using sodium tetraborate as electrolyte, and the effects of the coating on cell attachment were testified. This study aimed to investigate the effects of this cortex-like MAO coating on osseointegration. A sand-blasting and acid-etching (SLA) coating that has been widely used in clinical practice served as control. Topographical and chemical characterizations were conducted by scanning electron microscopy, energy dispersive X-ray spectrometer, X-ray diffraction, contact angle meter, and step profiler. Results showed that the cortex-like coating had microslots and nanopores and it was superhydrophilic, whereas the SLA surface was hydrophobic. The roughness of MAO was similar to that of SLA. The MAO and SLA implants were implanted into the femoral condyles of New Zealand rabbits to evaluate their in-vivo performance through micro-CT, histological analysis, and fluorescent labeling at the bone-implant interface four weeks after surgery. The micro-CT showed that the bone volume ratio and mean trabecular thickness were similar between MAO and SLA groups four weeks after implantation. Histological analysis and fluorescent labeling showed no significant differences in the bone-implant contact between the MAO and SLA surfaces. It was suggested that with micro/nanostructure and superhydrophilicity, the cortex-like MAO coating causes excellent osseointegration, holding a promise of an application to implant modification.