Defects were created in the mandible of a rabbit model whereby the right side was implanted with hydroxyapatite (HA) while the left side was left empty to act as control. Both the implant and control sites were evaluated clinically and histologically at 4,12,20,22 weeks. Decalcified sections were studied under confocal laser scanning microscope. No reactive cells were evident microscopically in all sections. There was bone ingrowth as early as 4 weeks when viewed by the topographic method. Enhancement of osteoconduction was evident by the presence of abundant capillaries, perivascular tissue and osteoprogenitor cells of the host. At 22 weeks, the implanted defect showed mature bone formation filling almost the whole field. This study demonstrated that the dense HA exhibits excellent biocompatibility as noted by the complete absence of reactive cells. It also promotes osteoconduction.
*Bone Substitutes ; *Hydroxyapatites ; Mandible/pathology ; Mandible/*surgery ; *Materials Testing ; Osseointegration/physiology

Bone is unique in its ability to adapt structure to functional requirements, but as is all too obvious in an ever-ageing population it is susceptible to a number of degenerative diseases. Therefore there is an increasing need for materials for bone replacement. Clearly, the ideal material with which to replace bone, would be bone itself, but the major problem now facing us is that there is an insufficient supply of the natural bone to satisfy the clinical requirements. Hence, there is a need for the development of chemically synthesised bone graft substitutes
*Bone Substitutes ; *Carbon ; Femur/pathology ; *Hydroxyapatites ; Microscopy, Electron, Transmission ; Osseointegration/*physiology ; Sheep ; *Silicones ; Structure-Activity Relationship

Micromotion and fretting damages at the dental implant/bone interface are neglected for the limitation of check methods, but it is particularly important for the initial success of osseointegration and the life time of dental implant. This review article describes the scientific documentation of micromotion and fretting damages on the dental implant/bone interface. The fretting amplitude is less than 30 µm in vitro and the damage in the interface is acceptable. While in vivo, the micromotion's effect is the combination of damage in tissue level and the real biological reaction.
Biomechanical Phenomena ; Bone and Bones ; anatomy & histology ; physiology ; Dental Implants ; Humans ; Mechanical Phenomena ; Movement ; Osseointegration ; physiology ; Stress, Mechanical ; Surface Properties

OBJECTIVETo evaluate clinical results and technical characteristics of implant-retained facial prosthesis.

METHODSSix patients with facial defects underwent implant retained prosthesis treatment, of which 3 orbita defects (including upper and lower eyelids, eyeball) in 3 cases, 2 ears defects in 2 cases, and a nose defect in one case. Under local anaesthesia 21 extra-oral implant were placed, facial prosthesis were individually made six month postoperatively. Follow up ranged from 6 month to 6 years.

RESULTSAll 21 implants osseointegrated well, implant lost and peri implantitis was not found. All 6 cases had individual facial prosthesis and were satisfied with the prosthesis.

CONCLUSIONSExtra oral implants provided excellent retainment for facial prosthesis; result of current silicon with individual color shade is encouragable.

Dental Prosthesis, Implant-Supported ; methods ; Facial Injuries ; surgery ; Female ; Follow-Up Studies ; Humans ; Male ; Maxillofacial Prosthesis ; Osseointegration ; physiology

OBJECTIVETo study the osseointegration of the nanophase hydroxyapatite biograde-coated implants and host bone.

METHODSNanophase hydroxyapatite biograde-coated implants, hydroxyapatite biograde-coated implants and noncoated Ti-6Al-4V implants were inserted into both femoral of Beagle canines the tissue response, dynamic osteogensis and SEM were studied at 4, 8 and 12 weeks.

RESULTSThe degradation of nanophase hydroxyapatite was slower than hydroxyapatite, dynamic osteogensis and the form of osteoblast were better than the control groups.

CONCLUSIONThe biological reaction of Nanophase hydroxyapatite biograde-coated implants is better than hydroxyapatite coated implant.

Animals ; Bone Substitutes ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Dogs ; Durapatite ; chemistry ; Male ; Materials Testing ; Nanoparticles ; Osseointegration ; physiology ; Surface Properties

Calcium phosphates ceramics are frequently used as bone substitute materials in clinics because they are similar to the bone in mineral phase, they are of no antigenicity, and they have good biocompatibility as well as excellent osteoconductivity. The question as to whether calcium phosphate biomaterials possess osteoinductivity has been debated for a long time. Up to now, extensive fundamental studies and clinical application have demonstrated that calcium phosphate ceramics with special structure may induce bone formation in soft tissue. In this paper are reviewed the discovery and confirmation of calcium phosphates ceramics with intrinsic osteoinductivity, the process and mechanism of osteoinduction, and the relationship between osteoinductivity of calcium phosphate materials and animal species, the mesenchymal stem cells related to osteoinduction, the application of osteoinductive biomaterials. The researches directed toward to the osteoinduction of calcium phosphate are prospected.
Biocompatible Materials ; chemistry ; Bone Substitutes ; chemistry ; Calcium Phosphates ; chemistry ; Ceramics ; chemistry ; Guided Tissue Regeneration ; Osseointegration ; physiology ; Tissue Engineering ; trends

A novel glass-ceramic has been derived from sol-gel process. In this study XRD and FTIR analysis confirmed that the main crystalline phases of the material were hydroxyapatite/fluoroapatite [Ca10(PO4)6(OH,F)] and beta-wollastonite[beta-CaSiO3]; SEM examination showed that the microstructure contained many micro pores of 2-3 microm. After pore-forming, the material possessed good macro porous structure: the size of macro pores was 300-400 microm in diameter, and pores interconnected each other. Bioactivity of the material was preliminarily evaluated in the simulate body fluid. SEM observation revealed that a lot of apatite granules had been formed on the surface of the material after soaking within 7 days. Result shows that the novel sol-gel derived apatite-wollastonite-containing glass-ceramic has good bioactivity. Porous materials have suitable microstructure as well as macrostructure, which make it an excellent material to be used as bone-repairing materials and bone tissue engineering carrier materials.
Apatites ; chemical synthesis ; chemistry ; Biocompatible Materials ; chemistry ; Bone Substitutes ; chemistry ; Ceramics ; chemical synthesis ; chemistry ; Humans ; Materials Testing ; Osseointegration ; physiology ; Osteogenesis ; physiology ; Porosity ; Silicic Acid ; chemical synthesis ; chemistry

OBJECTIVETo compare the surface apposition and the bone response at early period of implantation in two differently treated implants.

METHODSThe implants were subject to double acid-etched-H2O2/HCl-heat treatment and double acid-etching treatment, and then randomly implanted into the tibia of rabbits. After 2, 4, 8 weeks of follow up, the bone specimens containing implants were prepared and examined by a field emission SEM and EDX.

RESULTA layer rich with calcium and phosphorus was clearly demonstrated on the implants surface of both groups after 2 weeks of implantation, but it was mostly disappeared after 4 weeks. There were large amounts of osteoblasts cells on double acid-etched-H2O2/HCl-heat treated implants surface indicating the initiation of osteogenesis. After 8 weeks of implantation some new bones were attached on the implants surface in both groups, more bones attached were shown on double acid-etched- H2O2/HCl-heat treated implants surface.

CONCLUSIONA calcium and phosphorus-rich layer was formed on the implants surface of both groups at early period of implantation.

Animals ; Dental Implantation ; Dental Implants ; Dental Materials ; chemistry ; Dental Prosthesis Design ; Hydrogen Peroxide ; chemistry ; Osseointegration ; physiology ; Osteogenesis ; physiology ; Rabbits ; Surface Properties ; Tibia ; surgery ; ultrastructure ; Titanium ; chemistry

Using the CT data, we have constructed the finite element models of human femur distally amputated at high-position, middle-position and low-position, along with distally osseointegrated implant under the maximal load during a normal walking cycle. Results of finite element analysis revealed: the maximal stress of implant is produced near the exit of the amputated limb, where the fatigue breakpoint caused by cyclic stress would take place. With the ascending of truncated position, the peri-implant interfacial stress of bone increases. There is severe stress-shielding at the bone-implant interface, and there is concentration of stress at the end of implant and at the 3/4 point of femur, which would lead to bone loss and bone resorption and would shorten the longevity of implant. The results also showed that the curvature of natural bone has notable effect on the stress distribution, which should not be neglected. These data may provide reliable reference for the design and research of osseointegarted artificial limb.
Artificial Limbs ; Computer Simulation ; Femur ; physiology ; Finite Element Analysis ; Humans ; Imaging, Three-Dimensional ; Models, Biological ; Osseointegration ; physiology ; Prosthesis Design ; Stress, Mechanical

OBJECTIVETo investigate osteogenesis and integration of osteointergrated dental implants with marrow stromal osteoblast and cancellous bone matrix compound artificial bone (MCCAB) when embedded subcutaneously.

METHODSOsteointergrated dental implants (3 mm in diameter) were inserted into cancellous bone matrix (CBM) columns (5 mm in diameter). Marrow stromal osteoblast (MSO) were cultured and expanded in the column and on the surface. The osteointergrated dental implants loaded MSO-Alginate-CBM compound was formatted. This compound was then implanted subcutaneously in nude mice, and the osteointergrated dental implants loaded Alginate-CBM compounds were implanted as control. The compound was in the mice for 4 to 8 weeks and then harvested and assessed by means of gross observation, X-ray examination, histologic observation and computerized histomorphometry for evaluation of bone formation.

RESULTSThe osteogenesis of the osteointergrated dental implants loaded MSO-Alginate-CBM compound was better than that of the the osteointergrated dental implants loaded Alginate-CBM compound. Both intramembranous and cartilaginous osteogenesis was seen but the former was predominant. A large amount of new bone formed around the implant and integrated well with the implant. In the control, only slight cartilage osteogenesis was seen and no integration was found.

CONCLUSIONSThe results suggest that the new bone forms in the scaffolds and on the surface of the implant, and integration between the implant and artificial bone also occurs when they are implanted in the nude mice.

Animals ; Bone Matrix ; transplantation ; Bone Substitutes ; Cells, Cultured ; Dental Implantation, Endosseous ; methods ; Dental Implants ; Mice ; Mice, Nude ; Osseointegration ; physiology ; Osteoblasts ; transplantation ; Osteogenesis ; physiology ; Rabbits ; Tissue Engineering