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Since the discovery of Bioglass^® by Hench, bioactive glasses have been used in many medical applications, such as drug delivery systems, nonload-bearing implants, and bone cements because of their excellent bioactivity and biocompatibility. However, due to their poor mechanical properties, these glasses cannot be used in load-bearing applications, where the metallic alloys are still main materials. One useful approach to solving the mechanical limitations of bioactive glasses is to apply the glasses as the coating on mechanically tough substrates; it was also recognized early that bioactive glasses could be used as coatings for prosthetic metallic implants. In this paper, the mechanism, characterization, and current status of some methods of preparation for bioactive glass coating on implants are introduced. In the end, to get the homogeneous and compact coating with perfect bonding strength, some ideas of improving the performance of coatings are also presented.

Glass of the Si–Na–Ca–P system has been synthesized by normal melting and annealing technique. The obtained glass powders and annealed blocks were showed to be amorphous by X-ray diffraction (XRD). The thermal properties of glasses were analyzed by differential scanning calorimetry (DSC), it showed that the glass transformation temperature (T_g) was 556.3°C. The behavior of annealed glass discs in simulated body fluid solution (SBF) was studied in polyethylene containers at a constant temperature of 37°C for different time up to 14 days. The changes in the surface morphology and composition were observed by electronic probe microanalyzer (EPMA) associated with energy dispersive spectroscopy (EDS). Glass surface changed quickly as soon as immersion took place, and after longer soaking time, it showed different superimposed internal and external layers, which were identified as SiO₂-rich and CaO–P₂O₅-rich layers, and on the external layer, spherical particles were also discovered.

This paper reports for the first time the use of field-assisted sealing for bioactive implant coating applications. Field-assisted sealing (anodic bonding) of bioactive glass particles to bioinert glass enamel coating of titanium implant was investigated. Biocompatible titanium oxide interlayer was fabricated by deep thermal oxidation of 80 nm thick Ti thin film previously vacuum evaporated onto polished bioactive glass surface. Bioactive glass particle was anodically bonded via the interlayer to polished surface of bioinert glass enamel coating vacuum deposited onto Ti plate at 860°C. A total of 20 min preheating time with constant temperature increase rate, 5 min bonding time, and 100 V DC voltage were applied during field-assisted bond formation at 530°C in air.

Synthetic bioactive and bioresorbable composite materials are becoming increasingly important as scaffolds for bone tissue engineering. Next generation biomaterials should combine bioactive and bioresorbable properties to activate in vivo mechanisms of tissue regeneration, stimulating the body to heal itself and leading to replacement of the scaffold by the regenerating tissue. In the present chapter composite materials based on smart combinations of biodegradable polymers and bioactive ceramics, including hydroxyapatite and bioactive glasses, are discussed as suitable materials for scaffold fabrication. These composites exhibit tailored physical, biological and mechanical properties as well as predictable degradation behaviour. The appropriate selection of a particular composite for a given application requires a detailed understanding of relevant cells and/or tissue response. Knowledge concerning interactions between cells and their immediate local environment in composite scaffolds has deeply improved in the last years. An overview of these findings is presented highlighting the influence of material processing methods, scaffold microstructure as well as the importance of the nature and amount of the bioactive ceramic particulate included in specific polymer matrices. The chapter also emphasises the response diversity according to the cell type used in vitro or the chosen in vivo models (species and location), suggesting the utility of standardisation in this field of biomaterials science. Bioactive composites discussed in this chapter, enhanced by microstructural optimisation and surface engineering, are suggested as the materials of choice for development of optimal bone tissue engineering scaffolds.

The purpose of the present investigation was to clinically evaluate over a 6-12 month postsurgical period changes in the healing response of human intraosseous defects treated with open flap debridement with and without Bioglass® implantation. Patients were chosen for this study if they had at least 2 sites with attachment loss of ≥ 6 mm and radiographic evidence of intraosseous defects. Clinical measurements (probing depths (PD), attachment level (AL), and gingival recession (Rec) were recorded at baseline (day of the surgery), 6 and 12 months. The test defects were implanted with bioactive glass. The other sites served as unimplanted controls. At 1 year, significantly greater (P=0.0430) mean probing depth reduction was noted in the bioactive glass group (3.42 mm) compared to the control (4.31 mm). Attachment level gain was significantly improved (P=0.0016) in the bioactive glass sites (2.96 mm) compared to the control sites (1.48 mm). There was significantly less (P=0.0190) gingival recession in the bioactive glass sites (1.36 mm) compared to the control sites (1.90 mm). In conclusion, bioactive glass showed significant improvement in clinical parameters compared to open flap debridement alone. Moreover, changes in clinical parameters (PD reduction and AL gain) recorded 6 months postsurgery remained stable at the 12-month evaluation. Changes in Rec recorded at 12 months were significantly greater (P=.0104) than the 6 month values in both treatment groups.

Successful repair of fractures of the orbital and maxillary zygomatic complex has four prerequisities as through understanding of the regional anatomy; an accurate diagnosis; an unimbedded exposure, and in some cases rigid fixation of fracture with orbital for restoration of the premorbid form.

Material and methods: A retrospective case series of 50 patients with bioactive implants (BG implants) of S53P4 was carried out from 1992 to 1998 at the ENT-clinic of Turku University Central Hospital. All patients diagnosed as having complex maxillary fractures with orbital floor fractures or a large blow-out fracture. All subjects underwent a transconjunctival or subciliar approach with lateral canthotomy. After prolapsed orbital contents were elevated back into the orbit the BG implant was placed over the defect.

Results: On follow-up examinations, none of the 50 patients with BG-implants presented with any evidence of orbital dystopia or complications relating to the implant. Four patients (10%) had after surgery infraorbital nerve paresthesia and one etropium. Among the all control cases there were three cases (6%) of persistent diplopia and in one case we have removed the BG-implant three months after surgery. Postoperative computed tomographic scans showed adequate maintenance of orbital and maxillary sinus volume without and evidence of resorption of the BG implant. Four patients (10%) had persistent enophthalmos without any evidence of diplopia.

Summary: BG implants are promising and well tolerated material for the repair of orbital floor fractures. Compared to conventional methods, they carry less morbidity as no donor operation is needed.

Upon implantation bioactive glass undergoes a series of reactions that leads to the formation of a calcium phosphate-rich layer. Most in vitro studies of the changes that occur on the surface of bioactive glass have employed the use of buffer solutions with compositions reflecting the ionic composition of interstitial fluid. Although these studies have documented the physical chemical changes associated with bioactive glass immersed in aqueous media, they do not reveal the effect of serum proteins and cells which are present at the implantation site. In the present study, we document, using Atomic Force Microscopy (AFM) and Rutherford Backscattering Spectrometry (RBS), significant differences in reaction layer composition, thickness, morphology and kinetics of formation arising from the presence of serum proteins.

The data reveal that the uniform and rapid adsorption of serum proteins on the surface may serve to protect the surface from further direct interaction with the aqueous media, slowing down the transformation reactions. This finding is in agreement with previous studies that have shown that the presence of serum proteins significantly delays the formation of hydroxyapatite at the surface of bioactive glass. These data also support the hypothesis that initial reaction layers in vivo interact with cells to produce the tissue-bioactive glass interface typically observed on ex vivo specimens.