June Wilson

An Introduction to bioceramics

Alumina and zirconia, S. Hulbert bioactive glasses - materials science, L. Hench and O. Andersson bioactive glasses-materails science, L. Hench and O. Anderson applications, J. Wilson and R.P. Happonen A/W glass-ceramic - processing and properties, T. Kokubo A/W glass ceramic - clinical applications, T. Yamamuro bioactive glass-ceramics - ceravital, U. Gross et al machineable glass-ceramics, W. Holland and W. Vogel hydroxyapotite, R. LeGros and J. LeGros porous ceramics, R. Holmes and E. Schors resorbable calcium phosphates, C.P.A.T. Klein et al hydroxyapatite coatings, W. Lacefield bioactive glass coatings, L. Hench and O. Andersson pyrolytic carbon coatings, R.H. Dauskardt and R.O. Ritchie bioceramic composites, P. Ducheyne polyethylene-HA composites, W. Bonfield radiotherapy glasses, D. Day characterization of bioceramics, L. Hench regulation of medical devices, E. Horowitz and E. Mueller summary, L. Hench and J. Wilson appendices ASTM standards, J. Lemons and D. Greenspan.

Comparative bone growth behavior in granules of bioceramic materials of various sizes

Various bioceramic materials were implanted into 6-mm-diameter holes made in the femoral condyles of mature Japanese white rabbits using different-sized granules to find an optimal material and granule diameter for use as a bone graft. Bioceramics include a bioinert ceramic (Alumina), surface-bioactive ceramics [hydroxyapatite (HAp) and Bioglass(R)], and resorbable bioactive ceramics [alphatricalcium phosphate (alpha-TCP), beta-TCP, tetracalcium phosphate (TeCP), Te. DCPD, Te. DCPA, and low-crystalline HAp]. Granule sizes were 100-300, 10, and 1-3 microm. Bone growth behavior varied with the kind of bioceramic and the size used. For surface-bioactive ceramics, 45S5 Bioglass(R) led to more rapid bone proliferation than synthetic HAp. In resorbable bioactive ceramics, the order of resorption was: low-crystalline HAp and OCP > TeCP, Te DCPD, Te DCPA > alpha-TCP, beta-TCP. In terms of biocompatibility, alpha-TCP was better than beta-TCP.

Particulate bioglass compared with hydroxyapatite as a bone graft substitute

Bioactive ceramics, notably hydroxyapatite, have been used clinically in various situations in which bone augmentation and restoration are required. Particulate material has been used either alone or in conjunction with freeze dried or autologous bone, with variable clinical success. In this study a bioactive glass, 45S5 Bioglass, has been compared with hydroxyapatite in an animal model to discover whether the 2 major disadvantages of hydroxyapatite may be overcome. These are the difficulty of placing and retaining the particulate in the defect and the length of time needed before full bony restoration is achieved. Bioglass is shown to be easy to manipulate and hemostatic and allows full restoration of bone in 2 weeks, rather than the 12 weeks needed for the particulate hydroxyapatite to produce a comparable response. The Bioglass particulate is used up in the process, and any problems that may be associated with the production of a composite of bone and biomaterial are avoided in the fully restored bone. In any procedure that requires bony augmentation, this rapid response to Bioglass is expected to provide a clinical advantage.

Injectable bioglass as a potential substitute for injectable polytetrafluoroethylene

Injectable polytetrafluoroethylene (Teflon) and collagen have inherent problems that may prevent their long-term success. In search of a different injectable biomaterial we confirmed in rabbits the safety of injected Bioglass particles suspended in sodium hyaluronate. A second study was performed testing the ability of the Bioglass suspension to increase urethral resistance in pigs. Bioglass particles in suspension have the potential to substitute for polytetrafluoroethylene or collagen in the treatment of urinary incontinence or vesicoureteral reflux.

Clinical performance of skeletal prostheses

Low-friction total hip arthroplasties. Evaluation of the success of non-cemented porous and HA coated metal-UHMWPE total hip. Alumina-alumina and alimina-polythylene. Total hip replacement: metal-on-metal systems. A comparison artificial knee arthroplasties. Shoulder implant system. Elbow joint implant systems. Toe joint implant systems. Evaluation of limb lengthening techniques. Success of surgery on the anterior cervical spine: Smith-Robinson technique vs internal plates. Ventilation tubes. Ossicular replacement prostheses. Longevity of osseointegrated dental implants. Alveolar ridge maintenance implants.

Comparison of ossicular replacement materials in a mouse ear model.

Four biomaterials, UF45S5 Bioglass, Silastic, Plasti-Pore, and Proplast, were used to replace the incus in a mouse ear model. Bioglass, a bioactive glass ceramic, compared favorably with the other test materials in maintaining surgical positioning between malleus and stapes and remaining stable to a blast of nitrogen gas and to pick manipulation. In a short-term animal study, Bioglass showed histocompatibility comparable to that of these other implant materials now used in ossicular replacement surgery in humans.

Bone Growth into Spaces Between 45S5 Bioglass Granules

ABSTRACT Granules of Bioglass® 100–300 μm in diameter were implanted into 6mm diameter holes made in the femoral condyles of mature rabbits. As a control, HA granules of similar size were used. After 12 days new bone had grown into the defect to a depth of 1500 μm, equivalent to 10 layers of granules. Of these layers three or four were completely enclosed in new bone. By three weeks the whole defect was filled (to 3,000 μm) and approximately 10 layers of granules were completely enclosed. At five weeks this bone had continued to densify. In contrast only the outer layer of HA granules was surrounded by bone at two weeks although bone had infiltrated to the third or fourth layer. By three weeks bone had reached 1000 μm but even after six weeks had not reached, the center, being only 2500μm in thickness. In conclusion, the speed of bone growth around Bioglass® particles was faster and the new bone was denser than that associated with hydroxyapatite granules.

Current Status of the Development of BioglassR Ossicular Replacement Implants

The unique bonding characteristics of UF45S5 Bioglass®1, 2, 3 (discussed in another chapter in this book, reference 4) prompted these investigators to pursue a series of experiments to evaluate Bioglass® in a middle ear setting. The incus replacement model was chosen and developed since it replicated many of the unique requirements of clinical ossicular reconstruction. Results in 60 mice of Bioglass® incus replacement for periods of 21 to 300 days indicated that Bioglass® rods remained in position on malleus or stapes or both in 85% and were stable to a blast of nitrogen gas and/or pick manipulation in 85%. Histologic study revealed rods entirely covered by a very thin capsule, in places only 1 or 2 collagen fibers thick, covered by normal appearing middle ear mucosa without any sign of inflammation5.

Dental Applications of Bioglass® Implants

ABSTRACT Nearly twenty years of development and testing have led to two dental applications of a bioactive glass, 45S5 Bioglass®, in the form of implanted cones for the maintenance of the alveolar ridge of denture wearers and bioactive powders for repair of periodontal defects. In this paper four year clinical data for the bioactive glass cone implants are presented with 90% retention and only 7% dehiscence. These results are generally superior, in terms of both retention of cones and incidence of dehiscence compared with dense synthetic hydroxyapatite implants over equivalent time periods. Mechanistic reasons for the improved performance include: differences in interfacial bonding rates, greater thickness of interfacial bonding zones, lower elastic modulus mismatch between implant and tissues, presence of soft tissue as well as bone bonding and improved implant fit by use of special burs that match the cone implants. Histological analysis of endosseous ridge maintenance implants (ERMI) in dogs, combined with previous results from implantations in baboons, indicate that differences in interfacial reaction layers can explain the differing clinical behavior of bioactive dental implants.

Clinical application of hydroxyapatite

Publisher Summary Bioceramics have been widely used as bone replacement materials in orthopedic surgery. In particular, calcium phosphate ceramics, such as Hydroxyapatite (HA), have been applied as bioactive ceramics with bone-bonding capacities. As clinical use, generally HA has been used as a spacer, filler, and physicochemical bonding between bone and implant. Since porous HA block used as spacer is brittle and dense HA is difficult to make adhere to the bone, the use of HA spacer has decreased. To curb the loosening of the prosthesis, osteoconduction has to be continued at the interface between bone and implant even after onset of osteoporosis and therefore, not-resorbable crystalline HA has to be used. For this reason, the Interface Bioactive Bone Cement (IBBC) technique, which involves interposing crystalline HA granules at the interface between bone and bone cement at cementing during surgery, has been used. As non-resorbable crystalline HA and other resorbable bioceramics are completely different materials, it is necessary to understand their properties and characteristics accurately and they have to be applied in clinical cases. This chapter provides a comparison of different characteristics of HA and other bioceramics and introduces clinical application of HA.