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

OBJECTIVE: To investigate the preparation and properties of the novel silica (SiO ₂)/hydroxyapatite (HAP) whiskers porous ceramics scaffold. METHODS: The HAP whiskers were modified by the SiO ₂ microspheres using the Stöber method. Three types of SiO ₂/HAP whiskers were fabricated under different factors (for the No.1 samples, the content of tetraethoxysilane, stirring time, calcination temperature, and soaking time were 10 mL, 12 hours, 560℃, and 0.5 hours, respectively; and in the No.2 samples, those were 15 mL, 24 hours, 650℃, and 2 hours, respectively; while those in the No.3 samples were 20 mL, 48 hours, 750℃, and 4 hours, respectively). The phase and morphology of the self-made HAP whisker and 3 types of SiO ₂/HAP whiskers were detected by the X-ray diffraction analysis and scanning electron microscopy. Taken the self-made HAP whisker and 3 types of SiO ₂/HAP whiskers as raw materials, various porous ceramic materials were prepared using the mechanical foaming method combined with extrusion molding method, and the low-temperature heat treatment. The pore structure of porous ceramics was observed by scanning electron microscopy. Its porosity and pore size distribution were measured. And further the axial compressive strength was measured, and the biodegradability was detected by simulated body fluid. Cell counting kit 8 method was used to conduct cytotoxicity experiments on the extract of porous ceramics. RESULTS: The SiO ₂ microspheres modified HAP whiskers and its porous ceramic materials were prepared successfully, respectively. In the SiO ₂/HAP whiskers, the amorphous SiO ₂ microspheres with a diameter of 200 nm, uniform distribution and good adhesion were attached to the surface of the whiskers, and the number of microspheres was controllable. The apparent porosity of the porous ceramic scaffold was about 78%, and its pore structure was composed of neatly arranged longitudinal through-holes and a large number of micro/nano through-holes. Compared with HAP whisker porous ceramic, the axial compressive strength of the SiO ₂/HAP whisker porous ceramics could reach 1.0 MPa, which increased the strength by nearly 4 times. Among them, the axial compressive strength of the No.2 SiO ₂/HAP whisker porous ceramic was the highest. The SiO ₂ microspheres attached to the surface of the whiskers could provide sites for the deposition of apatite. With the content of SiO ₂ microspheres increased, the deposition rate of apatite accelerated. The cytotoxicity level of the prepared porous ceramics ranged from 0 to 1, without cytotoxicity. CONCLUSION SiO ₂/HAP whisker porous ceramics have good biological activity, high porosity, three-dimensional complex pore structure, good axial compressive strength, and no cytotoxicity, which make it a promising scaffold material for bone tissue engineering.
Animals ; Durapatite ; Porosity ; Vibrissae ; Apatites ; Ceramics ; Silicon Dioxide

The surface modification using cold plasma technique was introduced to hydroxyapatite(HA). The methods adopted in the study included the formation of bone-like apatite in simulated body fluid and the use of SEM, XPS and XRD. The results showed that the formation of bone-like apatite on HA modified by cold plasma was easier than that without modification. The active mechanism involves the impact of the particles with high energy and high activity against HA, which roughens and etches the surface of HA, heads to the distortion of HA crystal, and thus increases the dissolvability of HA and the local concentration of the Ca and P ions. This approach is helpful to the formation of bone-like appetite. The data demonstrate that the surface modification using cold plasma technique can increase the activity of HA.
Apatites ; chemistry ; Biocompatible Materials ; chemistry ; Cold Temperature ; Durapatite ; chemistry ; Humans ; Plasma ; chemistry ; Surface Properties

Stones in the seminal vesicle are extremely rare. We report a case with a large stone in a dilated seminal vesicle. A 20-year-old man presented with a large calcified density in the pelvic cavity on plain films. A 6.0 cm cone shaped stone was noted in the dilated left seminal vesicle diagnosed by radiological examination. We treated the patient by transperitoneal laparoscopic stone removal and partial seminal vesiculectomy. The composition of stone was carbonate apatite. This approach to the treatment of such pathological conditions of the seminal vesicles provides an additional option.
Apatites ; Carbon ; Humans ; Seminal Vesicles ; Young Adult

OBJECTIVETo prepare zinc-modified carbonated hydroxyapatite (Zn-CHA) coating material via sol-gel method and explore the influence of zinc substitution on physical and chemical properties of biomaterial samples.

METHODSTwo kinds of samples with different zinc content and Ca/P molar ratio were prepared. One was fabricated with 4% zinc and the Ca/P molar ratio was 1.67. Another was prepared with 8% zinc and the (Ca+Zn)/P molar ratio was 1.67. The coating samples were characterized by X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM). Furthermore, the zinc ions releasing ability of the coating samples were investigated by atomic absorption spectroscopy (AAS).

RESULTSXRD results revealed that the coating samples contained hydroxyapatite phase. After determination by FTIR, the biomaterial samples were found to contain carbonate and resemble biological apatites. High homogeneous and porous surfaces of coating samples were observed in SEM micrographs. According to the results of dissolution test, zinc was incorporated into hydroxyapatite lattice structure or surface absorbed when calcium was insufficient or sufficient respectively.

CONCLUSIONThe results demonstrate that phase-pure zinc-modified carbonated hydroxyapatite might be prepared through simple sol-gel method and have favorable antibacterial effect.

Apatites ; Biocompatible Materials ; Durapatite ; Microscopy, Electron, Scanning ; Polymethyl Methacrylate ; Spectroscopy, Fourier Transform Infrared ; X-Ray Diffraction ; Zinc

OBJECTIVETo explore the osteogenic activity of a micro-arc oxidation (MAO)-treated strontium (Sr)-substituted hydroxyapatite (Sr-HA) coating developed to enhance the osseointegration of titanium dental implants, and to investigate the strengthening mechanisms of bone bonding of crystalline hydroxyapatite (HA) with incorporation of strontium in vivo.

METHODSThe morphology and phase component of the oxidized film of Sr-HA and HA coated implants were examined by SEM and X-ray diffraction (XRD). Then, twenty-four implants were inserted into the metaphysis of rabbits tibias and femurs using polyfluorochrome sequential labeling. Four and 12 weeks following the surgery, the morphology and chemical composition of the bone-implant interfaces were evaluated by histological examination and energy-dispersive X-ray.

RESULTSThe XRD patterns showed that diffraction peaks of HA shift to lower 2θ values with Sr-addition, which resulted in decreases in lattice energy and then crystallinity. Sr-HA coating presented a microporous structure in the SEM observation. Meanwhile, Sr-HA coating exhibited osteogenic activity at the early stage of bone healing period and new bone mineral apposition ratio [(4.75 ± 0.46) microm/d] was significantly higher than that of the control group [(3.21 ± 0.44) microm/d]. An apatite layer was observed at the interface of bone-Sr-HA coating in light microscopy observation and energy-dispersive X-ray analysis. Then the apatite layer was precipitated and formed new bone which became mature bone and bonded tightly to the Sr-HA.

CONCLUSIONSStrontium-substituted hydroxyapatite coating shows high biological activity, which can accelerate the formation of apatite layer, hence the osteogenic ability.

Animals ; Apatites ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Dental Bonding ; Dental Implants ; Hydroxyapatites ; chemistry ; Microscopy, Electron, Scanning ; Osseointegration ; Rabbits ; Random Allocation ; Strontium ; chemistry ; Surface Properties ; Titanium ; X-Ray Diffraction

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 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

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