Role of phase separation on the biological performance of 45S5 Bioglass®

Tailoring of bioactive glass and glass-ceramics properties for in vitro and in vivo response optimization: a review

Bioactive glasses are inorganic biocompatible materials that can find applications in many biomedical fields. The main application is bone and dental tissue engineering. However, some applications in contact with soft tissues are emerging. It is well known that both bulk (such as composition) and surface properties (such as morphology and wettability) of an implanted material influence the response of cells in contact with the implant. This review aims to elucidate and compare the main strategies that are employed to modulate cell behavior in contact with bioactive glasses. The first part of this review is focused on the doping of bioactive glasses with ions and drugs, which can be incorporated into the bioceramic to impart several therapeutic properties, such as osteogenic, proangiogenic, or/and antibacterial ones. The second part of this review is devoted to the chemical functionalization of bioactive glasses using drugs, extra-cellular matrix proteins, vitamins, and polyphenols. In the third and final part, the physical modifications of the surfaces of bioactive glasses are reviewed. Both top-down (removing materials from the surface, for example using laser treatment and etching strategies) and bottom-up (depositing materials on the surface, for example through the deposition of coatings) strategies are discussed.

Functional engineering strategies of 3D printed implants for hard tissue replacement

Three-dimensional printing technology with the rapid development of printing materials are widely recognized as a promising way to fabricate bioartificial bone tissues. In consideration of the disadvantages of bone substitutes, including poor mechanical properties, lack of vascularization and insufficient osteointegration, functional modification strategies can provide multiple functions and desired characteristics of printing materials, enhance their physicochemical and biological properties in bone tissue engineering. Thus, this review focuses on the advances of functional engineering strategies for 3D printed biomaterials in hard tissue replacement. It is structured as introducing 3D printing technologies, properties of printing materials (metals, ceramics and polymers) and typical functional engineering strategies utilized in the application of bone, cartilage and joint regeneration.

Effects of Titanium Implant Surface Topology on Bone Cell Attachment and Proliferation in vitro

Purpose

Titanium is commonly used for implants because of its corrosion resistance and osseointegration capability. It is well known that surface topology affects the response of bone tissue towards implants. In vivo studies have shown that in weeks or months, bone tissue bonds more efficiently to titanium implants with rough surfaces compared to smooth surfaces. In addition, stimulating early endosseous integration increases the long-term stability of bone-implants and hence their clinical outcome. Here, we evaluated the response of human MG-63 osteoblast-like cells to flat and solid, compared to rough and porous surface topologies in vitro 1–6 days post seeding. We compared the morphology, proliferation, and attachment of cells onto three smooth surfaces: tissue culture (TC) plastic or microscope cover glasses, machined polyether-ether-ketone (PEEK), and machined solid titanium, to cells on a highly porous (average R_a 22.94 μm) plasma-sprayed titanium surface (composite Ti-PEEK spine implants).

Methods

We used immuno-fluorescence (IF) and scanning electron microscopy (SEM), as well as Live/Dead and WST-1 cell proliferation assays.

Results

SEM analyses confirmed the rough topology of the titanium implant surface, compared to the smooth surface of PEEK, solid titanium, TC plastic and cover glasses. In addition, SEM analyses revealed that MG-63 cells seeded onto smooth surfaces (solid titanium, PEEK) adopted a flat, planar morphology, while cells on the rough titanium surface adopted an elongated morphology with numerous filopodial and lamellipodial extensions interacting with the substrate. Finally, IF analyses of focal adhesions (vinculin, focal adhesion kinase), as well as proliferation assays indicate that MG-63 cells adhere less and proliferate at a slower rate on the rough than on a smooth titanium surface.

Conclusion

These observations suggest that bone-forming osteoblasts adhere less strongly and proliferate slower on rough compared to smooth titanium surfaces, likely promoting cell differentiation, which is in agreement with other porous implant materials.

Open Curettage With Bone Augmentation for Symptomatic Tumors and Tumor-like Lesions of Calcaneus: A Comparison of Bioactive Glass Versus Allogeneic Bone

Few studies have characterized the clinical outcomes of 45S5 Bioglass® applied as a bone graft to that of allogeneic bone applied in calcaneal open curettage. Therefore, the purpose of the present investigation was to compare the outcomes of patients with calcaneal tumors and tumor-like lesions treated by open curettage with 45S5 Bioglass® or allogeneic bone. Of the 31 patients who underwent open curettage (18 cases of unicameral bone cysts, 7 cases of aneurysmal bone cysts, and 6 cases of intraosseous lipoma), 16 (52%) received grafts with 45S5 Bioglass® and 15 (48%) with allogeneic bone. All the feet achieved bone fusion according to the modified Neer radiographic classification system at the last follow-up examination. The mean bone ingrowth time for the grafts with 45S5 Bioglass® versus allogeneic bone was 3.71 ± 0.86 versus 4.46 ± 1.04 months (p = .038), the mean bone healing time was 4.86 ± 0.93 versus 5.73 ± 1.07 months (p = .021), and the mean incision drying time was 7.2 ± 1.8 versus 8.2 ± 1.5 days (p = .047), respectively. No differences were found in the postoperative American Orthopaedic Foot and Ankle Society ankle-hindfoot scale scores between the 2 groups (p = .213). These results show that 45S5 Bioglass® can better facilitate the formation of new bone with a faster drying time of the incision than allogeneic bone. Although both materials can benefit the clinical outcomes of calcaneal tumors and tumor-like lesions, further studies are needed to observe the long-term complications and lesion recurrence rates.

Potential of tailored amorphous multiporous calcium silicate glass for pulp capping regenerative endodontics-A preliminary assessment

INTRODUCTION/OBJECTIVE

The tailored amorphous multi-porous (TAMP) material fabrication technology has led to a new class of bioactive materials possessing versatile characteristics. It has not been tested for dental applications. Thus, we aimed to assess its biocompatibility and ability to regenerate dental mineral tissue.

METHODS

30CaO-70SiO₂ model TAMP discs were fabricated by a sol-gel method followed by in vitro biocompatibility testing with isolated human or mini-swine dental pulp stem cells (DPSCs). TAMP scaffolds were tested in vivo as a pulp exposure (pin-point, 1 mm, 2 mm, and entire pulp chamber roof) capping material in the molar teeth of mini-swine.

RESULTS

The in vitro assays showed that DPSCs attached well onto the TAMP discs with comparable viability to those attached to culture plates. Pulp capping tests on mini-swine showed that after 4.5 months TAMP material was still present at the capping site, and mineral tissue (dentin bridge) had formed in all sizes of pulp exposure underneath the TAMP material.

CONCLUSIONS

TAMP calcium silicate is biocompatible with both human and swine DPSCs in vitro and with pulp in vivo, it may help regenerate the dentin bridge after pulp exposure.