ABSTRACT PURPOSE: Synthetic bone products such as biphasic calcium phosphate (BCP) are mixtures of hydroxyapatite (HA) and a- tricalcium phosphate (a- TCP). In periodontal therapies and implant treatments, BCP provides to be a good bone reconstructive material since it has a similar chemical composition to biological bone apatites. The purpose of this study was to compare bone regeneration capacity of two commercially available BCP. METHODS: Calvarial defects were prepared in sixteen 9-20 months old New Zealand White male rabbits. BCP with HA and a- TCP (70:30) and BCP with Silicon-substituted hydroxyapatite (Si-HA) and a-TCP (60:40) particles were filled in each defect. Control defects were filled with only blood clots. Animals were sacrificed at 4 and 8 week postoperatively. Histomorphometric analysis was performed. RESULTS: BCP with HAand a- TCP 8 weeks group and BCP with Si-HA and a- TCP 4 and 8 weeks groups showed statistically significant in crease (P<0.05) in augmented area than control group. Newly formed bone area after 4 and 8 weeks was similar among all the groups. Residual materials were slightly more evident in BCP with HA and a- TCP 8 weeks group. CONCLUSIONS: Based on histological results, BCP with HA and a- TCP and BCP with Si-HA and a- TCP appears to demonstrate acceptable space maintaining capacity and elicit significant new bone formation when compared to natural bone healing in 4 and 8 week periods.
Animals ; Apatites ; Bone Regeneration ; Bone Substitutes ; Calcium ; Calcium Phosphates ; Durapatite ; Humans ; Hydroxyapatites ; Male ; New Zealand ; Osteogenesis ; Rabbits

Bone-like apatite formation on the surface of calcium phosphate ceramics has been believed to be the prerequisite of new bone growth on ceramics and to be related to the osteoinductivity of the material. The research of the factors effecting bone-like apatite formation is a great help in understanding the mechanism of osteoinduction. This paper is aimed to a comparative study of in vitro formation of bone-like apatite on the surface of dense and rough calcium phosphate ceramics with SBF flowing at different rates. The results showed that the rough surface was beneficial to the formation of bone-like apatite, and the apatite formed faster in 1.5 SBF than in SBF. Rough surface, namely, larger surface area, increased the dissolution of Ca2+ and HPO4(2-) and higher concentration of Ca2+ and HPO4(2-) ions of SBF and was in turn advantageous to the accumulation of Ca2+, HPO4(2-), PO4(3-) near the ceramic surface. Local supersaturating concentration of Ca2+, HPO4(2-), PO4(3-) near sample surface was essential to nucleation of apatite on the surface of sample.
Apatites ; Biocompatible Materials ; Calcium Phosphates ; Ceramics ; Materials Testing ; Surface Properties

OBJECTIVETo establish an in vitro model for the apatite crystal mineralization. To evaluate the influences of bovine serum albumin (BSA) and fluoride to the mineralization of apatite crystal.

METHODSThe model was constructed using cation selective membrane (CMV) and dialysis membrane. Double distilled water (DDW), BSA, 5, 20, 100 mg x L(-1) fluoride were added into the reaction space of the model. Reaction was carried out at 37 degrees C for 3 days under gentle stirring. The crystals were identified by scanning electron microscope (SEM) and X-ray diffraction (XRD).

RESULTSThe model was established successfully. When DDW and BSA were added respectively, the main component of the deposit was octacalcium phosphate (OCP), but the shape and size of the crystals differs from each other. When fluoride with different concentration were added, the main component of the crystal turned to rod-like and prism-like fluoroapatite (FAP) crystal. The size and crystallinity of the FAP increased with the increase of the fluoride concentration.

CONCLUSIONIt is an effective way to evaluate the influence factors of the apatite crystal mineralization by using the in vitro model.

Apatites ; Calcium Phosphates ; Crystallization ; Fluorides ; In Vitro Techniques ; Phosphates ; X-Ray Diffraction

OBJECTIVETo investigate the apatite forming ability of pure titanium implant after micro-arc oxidation treatment in simulated body fluid (SBF) and obtain implants with calcium phosphate (Ca-P) layers.

METHODSThe implants were immersed in (SBF) after micro-arc oxidation treatment for different time lengths, and their apatite forming ability and the morphology and constituents of the Ca-P layers formed on the sample surface were analyzed using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and energy dispersive electron probe.

RESULTSAfter immersion in SBF, large quantities of Ca-P layers were induced on the surface of the samples. The Ca-P layers were composed of octacalcium phosphate and carbonated hydroxyapatite, and the crystals showed a plate-like morphology with an oriented growth.

CONCLUSIONThe implants with micro-arc oxidation treatment show good apatite forming ability on the surface with rich calcium and phosphorus elements. The formed layers are composed of bone-like apatite including octacalcium phosphate and carbonated hydroxyapatite.

Apatites ; chemistry ; Biomimetic Materials ; chemistry ; Body Fluids ; chemistry ; Calcium Phosphates ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Durapatite ; chemistry ; Oxidation-Reduction ; Prostheses and Implants ; Random Allocation ; Surface Properties ; Titanium ; chemistry

The formation of bone-like apatite on porous HA/beta-TCP bioceramics in dynamic simulated body fluid (SBF) undergoing a simulated inflammation procedure (pH = 6.5) was investigated in order to study the mechanism of osteoinduction and build a new method to choose biomaterials with better bioactivity. The results showed that the surface of porous HA/beta-TCP bioceramics which underwent a simulated inflammation procedure in dynamic SBF was more smooth. The light acidity in the simulated inflammation procedure would dissolve the fine grains and the parts possessing smaller curvature radius on the surface of porous HA/beta-TCP bioceramics, which would reduce the bioceramics solubility. Followed in normal SBF (pH = 7.4), the amount of bone-like apatite formed on the porous HA/beta-TCP bioceramics was less than that of porous HA/beta-TCP bioceramics incubation in normal SBF all along. The results also showed that the amount of bone-like apatite formed on the porous HA/beta-TCP bioceramics sintered by a microwave plasma was more than that of porous HA/beta-TCP bioceramics sintered by a conventional furnace.
Apatites ; chemistry ; Biocompatible Materials ; chemistry ; Body Fluids ; chemistry ; Bone Cements ; chemistry ; Bone Substitutes ; chemistry ; Calcium Phosphates ; chemistry ; Ceramics ; Hydroxyapatites ; chemistry ; Inflammation ; Materials Testing ; methods ; Microwaves ; Osseointegration ; Porosity ; Surface Properties

PURPOSE: Biphasic calcium phosphates have been of great interest recently. Mixing adequate ratios of hydroxyapatite(HA) and beta-tricalcium phosphate(beta-TCP) allowed to control the resorption rate without distorting its osteoconductive property. This study evaluated the bone formation effect of newly developed biphasic calcium phosphate(BCP) in calvarial defect of rabbits. MATERIALS AND METHODS: 6 male New Zealand rabbits were used. Four defects with 8mm in diameter were created on each animal. BCP with HA/beta-TCP ratio of 7:3 and particle size of 0.5~1.0 mm was used as the test group and bovine bone with 0.25~1.0 mm particle size, as the control group. Both test and control group materials were randomly implanted in the calvarial defects and were covered witha polymer membrane. The animals were sacrificed after 12, 24, and 48 weeks of implantation under general euthanasia. Resin blocks were obtained and were stained by masson's trichrome for histological observation. RESULTS: Overall results were uneventful without any defect exposure or inflammation. The amount of new bone formation and bone maturity increased with increase in healing period at both groups. New bone in test group was mostly formed along the material particle surrounded by osteoblasts, and observation of osteoblastic stream was also present. Bone maturity increased as it was closer to thedefect margins. Under the same healing period, the test group showed more bone formation than the control group with more stable bovine bone particles remaining even after 48 weeks, whereas considerable resorption took place in BCP. Almost total defect closure was observed in test group with new bone formation in the central part of the defect. However, limited new bone formation was observed in the control group. CONCLUSION: Within the limits of the study, the present study reveals the newly developed BCP to be a good osteoconductive material. However, further studies are needed to be conducted in a different study model with a larger sample size.
Animals ; Calcium ; Calcium Phosphates ; Durapatite ; Euthanasia ; Humans ; Hydroxyapatites ; Hypogonadism ; Inflammation ; Male ; Membranes ; Mitochondrial Diseases ; Ophthalmoplegia ; Osteoblasts ; Osteogenesis ; Particle Size ; Pilot Projects ; Polymers ; Rabbits ; Rivers ; Sample Size

OBJECTIVETo investigate the functions of sodium tripolyphosphate (STTP) and polyacrylic acid (PAA) in the process of collagen biomimetic mineralization. This would allow future applications to other collagen matrices such as bone collagen or 3-D collagen scaffolds.

METHODSGlass cover slips and transmission electron microscopy (TEM) grids were coated with reconstituted typeIcollagen fibrils. Mineralization of the reconstituted collagens was demonstrated with scanning electron microscopy (SEM) and TEM using a Portland cement-containing resin composite and a phosphate-containing fluid in the presence of PAA and STTP. The rest were immersed in a biomimetic remineralization medium without PAA and/or STTP (control).

RESULTSIn the presence of PAA and STTP in the mineralization medium, intrafibrillar mineralization based on the non-classical crystallisation pathway could be identified. Mineral phases were evident within the collagen fibrils as early as 12 h after the initially-formed amorphous calcium phosphate nanoprecursors were transformed into apatite nanocrystals. Collagens at 72 h were heavily mineralized with periodically arranged intrafibrillar apatite platelets. Conversely, only large mineral spheres with no preferred association with collagen fibrils were observed in the absence of biomimetic analogues in the medium (control).

CONCLUSIONSIntrafibrillar apatite deposition can be achieved via biomimetic mineralization system containing PAA and STTP when amorphous calcium phosphate precursor is stabilized.

Acrylic Resins ; chemistry ; Apatites ; Biomimetics ; Bone and Bones ; Calcium Phosphates ; Collagen ; Collagen Type I ; chemistry ; Composite Resins ; Humans ; Microscopy, Electron, Transmission ; Minerals ; Phosphates ; Polyphosphates ; chemistry ; Tissue Scaffolds

OBJECTIVE: To study the preparation and properties of the hyaluronic acid (HA)/α-calcium sulfate hemihydrate (α-CSH)/β-tricalcium phosphate (β-TCP) material (hereinafter referred to as composite material). METHODS: Firstly, the α-CSH was prepared from calcium sulfate dihydrate by hydrothermal method, and the β-TCP was prepared by wet reaction of soluble calcium salt and phosphate. Secondly, the α-CSH and β-TCP were mixed in different proportions (10∶0, 9∶1, 8∶2, 7∶3, 5∶5, and 3∶7), and then mixed with HA solutions with concentrations of 0.1%, 0.25%, 0.5%, 1.0%, and 2.0%, respectively, at a liquid-solid ratio of 0.30 and 0.35 respectively to prepare HA/α-CSH/ β-TCP composite material. The α-CSH/β-TCP composite material prepared with α-CSH, β-TCP, and deionized water was used as the control. The composite material was analyzed by scanning electron microscope, X-ray diffraction analysis, initial/final setting time, degradation, compressive strength, dispersion, injectability, and cytotoxicity. RESULTS: The HA/α-CSH/β-TCP composite material was prepared successfully. The composite material has rough surface, densely packed irregular block particles and strip particles, and microporous structures, with the pore size mainly between 5 and 15 μm. When the content of β-TCP increased, the initial/final setting time of composite material increased, the degradation rate decreased, and the compressive strength showed a trend of first increasing and then weakening; there were significant differences between the composite materials with different α-CSH/β-TCP proportion ( P<0.05). Adding HA improved the injectable property of the composite material, and it showed an increasing trend with the increase of concentration ( P<0.05), but it has no obvious effect on the setting time of composite material ( P>0.05). The cytotoxicity level of HA/α-CSH/β-TCP composite material ranged from 0 to 1, without cytotoxicity. CONCLUSION The HA/α-CSH/β-TCP composite materials have good biocompatibility. Theoretically, it can meet the clinical needs of bone defect repairing, and may be a new artificial bone material with potential clinical application prospect.
Calcium Phosphates ; Bone and Bones ; Phosphates

PURPOSE: The purpose of this study was to determine the biological effects of cyanoacrylate-combined calcium phosphate (CCP), in particular its potential to act as a physical barrier - functioning like a membrane - in rabbit calvarial defects. METHODS: In each animal, four circular calvarial defects with a diameter of 8 mm were prepared and then filled with either nothing (control group) or one of three different experimental materials. In the experimental conditions, they were filled with CCP alone (CCP group), filled with biphasic calcium phosphate (BCP) and then covered with an absorbable collagen sponge (ACS; BCP/ACS group), or filled with BCP and then covered by CCP (BCP/CCP group). RESULTS: After 4 and 8 weeks of healing, new bone formation appeared to be lower in the CCP group than in the control group, but the difference was not statistically significant. In both the CCP and BCP/CCP groups, inflammatory cells could be seen after 4 and 8 weeks of healing. CONCLUSIONS: Within the limits of this study, CCP exhibited limited osteoconductivity in rabbit calvarial defects and was histologically associated with the presence of inflammatory cells. However, CCP demonstrated its ability to stabilize graft particles and its potential as an effective defect filler in bone augmentation, if the biocompatibility and osteoconductivity of CCP were improved.
Animals ; Bone Regeneration ; Calcium ; Calcium Phosphates ; Collagen ; Cyanoacrylates ; Hydroxyapatites ; Membranes ; Osteogenesis ; Porifera ; Rabbits ; Transplants

The feasibility of anterior lumbar intervertebral fusion with artificial bone in place of autogenous bone was investigated. Porous hydroxyapatite (HA)/ZrO2 ceramics loading bone morphogenetic protein (BMP) were implanted after removal of lumbar vertebral disc in rabbits. The adjacent intervertebral discs were also removed by the same way and autogenous illic bone was implanted. SEM observation and biomechanical test were carried out. Compound bone had a bit lower osteoinductive activity than autogenous bone by SEM (Osteoinductive activity of artificial bone in 12 weeks was the same as that of autogenous bone in 9 weeks). Biomechanical test revealed that compound bone had lower anti-pull strength than autogenous bone (P < 0.001), but there was no significant difference in anti-pull strength between compound bone at 12th week and autogenous bone at 9th week (P > 0.05). It was concluded that compound bone could be applied for anterior spinal fusion, especially for those patients who can't use autogenous bone.
Biocompatible Materials/therapeutic use ; Bone Morphogenetic Proteins/*therapeutic use ; Calcium Phosphates ; Durapatite ; Hydroxyapatites ; Implants, Experimental ; Intervertebral Disk/surgery ; Lumbar Vertebrae/*surgery ; Spinal Fusion/*methods ; Spinal Injuries/*surgery