Papers by Keyword: Osteoconduction

Abstract: Titanium was the most commonly used metal in orthopedic implant. However, no direct chemical bond would be possible between the implant and surrounding bone tissue, and so the titanium implants lack the potential to induce rapid bone formation. Coating the titanium with a bioresorbable and osteoconductive layer would have a significant osseointegration. The purpose of this study was to fabricate and characterize calcium carbonate coating. The coating was fabricated on Ti substrate by converting of CaO coating in humidity environment under CO₂ flow. The CaO coating was deposited by sandblasting process. The CaCO₃ coating was approx. 1.85 µm thick and covered the surface’s surface uniformly. The coating strength was approx. 16.1 MPa and the Ca content in the coating was 2.02 mg/mm².

Abstract: Bone infections are challenging due to their difficult and prolonged treatment, considerable possibility of relapse and strong negative physical and emotional impact. Since their treatment require thorough excisions, bone substitutes have been studied for restoring bone continuity, but with limited efficacy due to the pathophysiology of bone infections; one of the classes which proved to be efficient were the BioActive Glasses [BAG], synthetic biocompatible inorganic materials with a controlled ionic release, with demonstrated properties of wound healing, osteoconduction, angiogenesis and antibacterial activity. This paper presents the clinical experience from a Level 1 Trauma Centre where post-traumatic osteitis was treated using BioActive Glasses as bone fillers, demonstrating the potential clinical impact of these materials. The outcome of the patients was favourable, with no relapse of sepsis, therefore proving the efficacy of BAG in cases with limited grafting possibilities

Abstract: Bioceramics draw attention in bone tissue engineering field since their biomimetic properties regarding bone attribute. In this context, a concept of smart bioceramics granules made of Hydroxyapatite have been set up, enhancing surface area available to body fluids containing proteins and cell adhesion for bone forming respectively thanks to microporosities and macropore concavities. New “hollow shell” granules were developed and assessed by physico-chemical characterizations, in-vitro experiments and in-vivo implantation in comparison with classical round granules. This new original galenic formulation showed promising potential in cell carrying and osteoconduction matter.

Abstract: Various kinds of materials have been found to bond to living bone and some of them are clinically used as important bone substitutes. However, they can not be used under load-bearing conditions, since their fracture toughness are not so high as that of human cortical bone. All of them are based on calcium phosphate or silicate. The present authors recently showed that even Ti metal and its alloys having high fracture toughness can show bone-bonding bioactivity, if they are subjected to simple chemical and heat treatments to form some kind of titanium oxide or titanates on their surfaces. They can show not only bone-bonding property, but also novel functions such as osteoinduction, release of antibacterial or bone-growth promoting ions etc.

Abstract: We have previously shown that synthetic octacalcium phosphate (OCP) displays highly osteoconductive and biodegradable characteristics. However, OCP cannot be sintered without thermal decomposition due to the existence of water molecules in the structure. The acquisition of the moldability and the improvement of the handling property in this material are subjects for the clinical use. In the present study, we prepared OCP complex with hyaluronic acid (Hya) that could be used in the injectable form and further examined the bone tissue reaction to cortical bone by placing the complex directly on an 8-weeks-old ICR mouse calvaria in comparison with the placement of OCP granules only. The granule form of OCP (between 300 to 500 μm in diameter) was mixed with sodium hyaluronic acid with molecular weights 90 x 10⁴. The complex revealed an injectable characteristic if it was utilized in a syringe. After polytetrafluoroethylen ring was mounted on mouse calvaria, the inner space of the ring was filled with the complex and left the complex as it is for 6 weeks. Histological examination using the decalcified specimens indicated that the OCP/Hya complex exhibited greater bone formation than OCP granules only group within the ring at 6 weeks. The results suggested that the OCP/Hya complex could be used as an injectable and osteoconductive bone substitute material in many clinical situations.

Abstract: The objective of this study was to investigate the bone repair of carbonate apatite (cHA) in comparison to hydroxyapatite (HA, control group) on osseous repair of rabbit’s tibia. Spheres (400-500 µm) of both materials were synthesized under 37°C (cHA) and 90°C (HA) and were not sinterized. Ethics Commission on Teaching and Research in Animals approved this project (CEPA/NAL 208/10). Six White New Zealand rabbits were submitted to general anesthesia and one perforation (2mm) was made in each tibia for implantation of cHA (left tibia) and HA spheres (right tibia). After 4 weeks all animals were killed and one fragment of each tibia with the biomaterial was collected with a total of 6 bone blocks for each group. Five bone blocks of each group were demineralized and 5-µm thick semi-serial sections were stain with Hematoxillin and Eosin and Trichromic of Masson for histological analysis and two fragments were collected and embedded in a methacrylate-based resin and cut into slices with ~30 µm and were analyzed by light microscopy (bright field and polarized microscopy). Both groups didn’t show the spheres after 4 weeks, new-formed bone was observed from the periphery toward to the center of the surgical defect, which was even filled with connective tissue. Both materials are biocompatible, promote osteoconduction and showed to be resorbable.

Abstract: We previously found that a positively charged Ti metal has a higher apatite forming ability in vitro than a non-charged Ti metal. For in vivo analysis using a rabbit model, two types of Ti metal were examined: porous Ti metals heat-treated subsequent to a mixed acid treatment (MHs) and porous Ti metals not heat-treated subsequent to the same mixed acid treatment (MOs). Although MHs and MOs had the same macro- and micro-structure, they had different surface charges. MHs, considered positively charged, had significantly higher bone ingrowth than MOs, considered charged zero. Similarly, MHs had significantly higher percentages of bone–implant contact than MOs at 3- and 6-week. A simple heat treatment made acid-treated porous titanium implants more osteoconductive. These results suggest that a positive charge obtained by a heat treatment enhances bioactivity of acid-treated titanium implants.

Abstract: In a previous study, we have reported that sodium removal by dilute hydrochloric acid (HCl) converted the sodium titanate layer on the surface of an alkali-treated porous titanium into titania with a specific structure that has better bioactivity than sodium titanate. We have shown that a porous titanium with this treatment have good osteoinductivity in soft tissue of canines. In the present study, we investigated the effect of this treatment on the osteoconductive abilities of porous bioactive titanium implant in the long term. Three types of surface treatments were applied: (a) no treatment , (b) alkali, hot water, and heat treatment ( conventional treatment: W-AH treatment), and (c) alkali, dilute HCl, hot water, and heat treatment (Na-free treatment: HCl-AH treatment). We then examined the osteoconductivity of the materials implanted in the femoral condyles of Japanese white rabbits at 6, 12, 26, and 52 weeks. The results showed that the bone ingrowth in HCl-AH porous bioactive titanium was significantly higher than in W-AH porous bioactive titanium at 52 weeks. Therefore, sodium removal has a positive effect on the osteoconductivity of the porous bioactive titanium implant in the long term.

Abstract: In this study, the chitosan scaffold was modified with the simulated body fluid (SBF) which would create a biomimetic layer on the interface between tissues and scaffolds for the bone formation. To investigate the in vivo osteoinduction, the chitosan scaffolds immersed in the SBF for different times were implanted into the calf muscle in male Wistar rats. The tissues blocks containing the scaffolds were harvested at different periods for bone induction assay and examined histologically. Hematoxyline and Eosin staining (H & E staining), Masson’s Trichriome staining and alkaline phosphatase staining (ALPase), were performed for the observation of in vivo biocompatibility, collagen deposition and ALPase activity. Immunohistochemical staining of osteopontin (OPN) and bone sialoprotein (BSP) were used to examine gene expression of these bone proteins and to determine possible development stage of osteoinduction in the specimens with SBF modification. The results in this research suggested that the SBF modification would improve the biocompatibility of chitosan scaffolds, revealed by the decrease in foreign body reaction. With the SBF treatment, the expression of osteoblastic differentiation, including ALPase, OPN and BSP, would be also enhanced. Besides, the above tendencies would be more significant with the longer time for SBF immersion. In conclusion, the chitosan scaffolds modified by using SBF bioreactor would possess excellent biocompatibility and high potential in the promotion of bone regeneration.

Abstract: Historically the function of biomaterials has been to replace diseased, damaged and aged tissues. First generation biomaterials, including bio ceramics, were selected to be as inert as possible in order to minimize the thickness of interfacial scar tissue. Bioactive glasses provided an alternative from the 1970’s onward; second generation bioactive bonding of implants with tissues and no interfacial scar tissue. This chapter reviews the discovery that controlled release of biologically active Ca and Si ions from bioactive glasses leads to the up-regulation and activation of seven families of genes in osteoprogenitor cells that give rise to rapid bone regeneration. This finding offers the possibility of creating a new generation of gene activating bioceramics designed specially for tissue engineering and in situ regeneration of tissues.