Objective To investigate and compare the osteogenic potential of three kinds of calcium phosphate ceramic as carriers for recombinant human bone morphogenetic protein-2(rhBMP-2) in vivo.Methods BCPceramics (HA,TCP,HA/TCP) impregnated with rhBMP-2 (experimental groups) and without rhBMP-2(control groups) were implanted into 6 muscles pockets on the dorsum of 3month-old Wistar rabbits. The rabbits were sacrificed 2, 4 and 8 weeks after implantation and bone induction was estimated by alkaline phosphatase(ALP) activity measurement. The implants were also examined histologically and histomorphometrically by HE staining and computerized graphical analysis. Results The ALPactivity of implants withrhBMP-2 was higher than that of control groups(P＜0.05), but there was no difference between 2 and 4 weeks in experimental groups. In all experimental groups,theimplants exhibited that new bone formation increased with the lapse of time. The amount of new bone formation is more in -HA/rhBMP-2 group than in the other two group in the 2nd and 4th weeks, but there was no difference between them (P＞0.05).In the 8th week, the amount of bone formation was most in HA/TCP with -rhBMP-2, and was more than that in the 2nd and 4th weeks. Whereas in control groups, there was only fibrous connective tissue. Conclusion HA/TCP- is a good carriers of rhBMP-2 and can be used as bone substitutes clinically.
OBJECTIVE: To evaluate the clinical effect of drilling procedure following the hydroxyapatite orbital implantation. METHODS: From February 1996 to April 2000, 146 consecutive patients who received hydroxyapatite orbital implant were drilled and inserted a motility peg 6 to 16 months after hydroxyapatite implantation. Among them, there were 97 males and 49 females, aged from 18 to 60 years old, of the 146 motility pegs, 36 were sleeved pegs and 110 were nonsleeved. Goldman visual field analyzer was applied to measure the degree of artificial eye’s movement before and after drilling. RESULTS: Followed up for 1 to 40 months, no secondary infection occurred. The mobility of the prosthesis increased from (18.7 +/- 3.8) degrees preoperatively to (42.3 +/- 3.7) degrees postoperatively. CONCLUSION: The delayed drilling procedure and motility peg insertion improve the range of movement and the sensitivity of the artificial eye with a low rate of complications.
Abstract To investigate the ectopic new bone formation following implantation of bovine hydroxyapatite Bio-oss together with free periosteum, 12 chabb: ch rabbits were selected. In 10 rabbits, Bio-oss block together with free periosteum was implanted in the gastrocnemius muscle of one leg randomly, and Bio-oss block alone was implanted in the same muscle of the other leg. In the other 2 rabbits, the periosteum was implanted into the gastrocnemius musle of both legs. Histologic examination and quantitative analysis of newbone formation were performed at 3 and 6 weeks postoperatively. The results showed that in the legs implanted bovine hydroxyapatite Bio-oss together with freeperiosteum, new bone formation began at 5th day after implantation. The area ofnew bone composed of 19.0% of the specimens at 3 weeks postoperatively. No boneformation through out the experimental period in Bio-oss block alone implantedlegs and also periosteum implanted legs. We concluded that bovine hydroxyapatite Bio-oss has a good capacity of osteoconduction. New bone can be formed after the implantation of hydroxyapatite combined with free periosteum.
The primary results of five patients in whomthe block hydroxyapatite artificial bone (BHAB)used in maxillofacial plastic repair were reported. All incisions healed up with no evidence ofinfection. None of the implants was rejected norhad resorption changes. Satisfactory estheticaleffects were maintained. The results demonst-rated BHAB had a good biocampatibility andcould be used as a bone graft substitute inmaxillofacial plastic repair. This kind of material could be carved and contoured ...
To observe the collagen-hydroxylaptite composite in the repair of bone defect, ten minipigs were chosen to make a mandibular dafect measuring 2 cm in diameter and the composite was implanted, while the use of autogenous bone graft and the blank wese served as control. On the 4, 8, 12, 24 and 48 weeks after the operation, the animals were sacrificed and the samples were examined under light microscope. The result showed that: no infection or necrosis occurred. The composite coalesced with host bone and the outcome was similar to that of the autogenous bone graft. No foreign body giant cells or vacuum left from osteonecrosis was observed. It was suggested that the composite had the advantage of abundant supply, easy to handle and no harm. The biocompatibility was good and might be hopeful as a bone substitute.
Natural nonorganic bone(NNB) was obtained after the fresh bone of pig was heated to 100℃. The NNB was white and in a shape as its original bone.The tensile strength of the compact bone was 200kg/cm3 and that of the cancellous bone was 25kg/cm3. The ratio of calcium to phosphorus was 10∶6. The main componentwas hydroxyapatite. The material was composed of trabeculae and intertrabecular spaces. Three experiments were performed. Experiment 1: 18 pieces of NNB in a size of 0.5×0.5×0.5cm3 were implanted intothe back muscle of 18 rabbits. At 4, 8 and 12 weeks after the operation, 6 specimens were obtained seperately and were stained by HE, and then examined under microscope. The result showed that the mesenchymal cells had no regeneration and differentiation, and the NNB and the surrounding tissues had no evidence of formation of new bone or chondrosynthesis. This NNB did not produce rejection reaction between tissues but the new blood vessels could easily grow into the space of the NNB. The fibrils had intimate contact with NNB. Experiment 2: The NNB and hydroxyapatite(HA) were mixed to make a cylindroid body with 2mm in diameter and 4mm in length and was implanted in the bilateral tibias of 40 rabbits, respectively. The roentgenography, fluroscent microscopic examination and histological observation were carried out at 2, 3, 4 and 8 weeks after the implantation. Experiment 3: In 50 rabbits, a defect of 2.5cm was made on both radius, and in one sideNNB was implanted and the other side was served as the control. Another 50 rabbitsHA was implanted in the defect in one side and the other side was served as the control. The results showed that in the NNB group at the 16th week, the bone united in 16 of the 30 cases, while in the HA group, in the 30 cases,only 2 had the bone united, while those of the controls no union had occurred.It was suggested that NNB had more formation of new bone than HA did.
Abstract To restore the bone defect after curettage of bone cyst, hydroxyapatite bioactive microcrystal glass (HBG) was used. From 1990 to 1995, HBG was applied in 17 cases. The bone involved were humerus, femur, tibia and fibula. Among them, 6 were complicated with pathological fracture. After eradication of the focus, the cyst was filled in ZnCl2 powder and irrigated with saline, then particles or segments of HBG were implanted into the cavity. The fracture were fixed with Enders rod. All the extremities were immobilized with plaster splint for about 6 to 8 weeks. Three months later, the lower limbs began to have functional exercises. By X-ray examination, the border between HBG and bone was clear in 2 weeks, after 1 month the clear border become blurred, and 2 months after operation, HBG was intermingled with bone. After 1 year there was neither absorption of bone nor HBG. No recurrence of the aptic lesion occurred in 1 year. HBG was a kind of artificial bone composed of hydroxyapatite and bioactive microcrystal glass, the latter contained silicon.It was characterized by its bioactivity, osteoinductivity and good tissue compatibility. The microcrystal would facilitate the growth of osseous tissues, which caused HBG intermingled with the surrounding bone. The source of HBG was abundant. It might be an ideal artificial bone.
Objective To investigate the influence of different dose levels of hydroxyapatite/tricalcium phosphate (HA/TCP) on the proliferation and alkalinephosphatase (ALP) activity of rabbit osteoblasts. Methods Three different doselevels of HA/TCP (10%, 40%, 70%) were co-cultivated with rabbit osteoblasts respectively. The proliferation and ALP expression capacity of osteoblasts were examined with MTT method and enzyme histochemistry once every 24 hours until 5 days. Three control groups of other materials were treated and examined in the sameway: rabbit osteoblasts as normal control; polyvinylchloride as positive control; titanium alloy as negative control. Results There was remarkable timeeffect relationship in the proliferation of osteoblasts. Ten percent HA/TCP did not affect osteoblasts growth while 40% HA/TCP could slow the cell growth rate down though time-effect relationship still existed. The proliferation of osteoblasts stagnated when co-cultivated with 70% HA/TCP. On the other hand, 10% HA/TCP could cause reversible damage on ALP activity of osteoblasts, whereas when the dose was40%, and the cultivation lasted 6 days the damage was irreversible. Three different dose levels of titanium alloy (10%, 40%, 70%) had no effect on the proliferation or ALP activity of osteoblasts. Conclusion Dosage is an important factor affecting the biocompatibility evaluation of biomaterial. It suggests that dose choosing should be more specified upon each individual biomaterial. It also indicates that ALP may be a good supplementary index of the cell compatibility of material.
Objective To evaluate the feasibility and the value of the layered cylindric collagenhydroxyapatite composite as a scaffold for the cartilage tissue engineering after an observation of how it absorbs the chondrocytes and affe cts the cell behaviors. Methods The chondrocytes were isolated and multiplied in vitro, and then the chondrocytes were seeded onto the porous collagen／h ydro xyapatite composite scaffold and were cultured in a three-dimensional environme n t for 3 weeks. The effects of the composite scaffold on the cell adhesivity, proliferation, morphological changes, and synthesis of the extracellular matrix were observed by the phase-contrast microscopy, histology, scanning electron micros copy, and immunohistochemistry. Results The pore diameter of the upper layer of the collagen-hydroxyapatite composite scaffold was about 147 μm. and the porosity was 89%; the pore diameter of the bottom layer was about 85 μm and the porosity was 85%. The layered cylindric collagenhydroxyapatite composite scaffold had good hydrophilia. The chondrocytes that adhered to the surface of the scaffold, proliferated and migrated into the scaffold after 24 hours. The chondrocytesattached to the wall of the microholes of the scaffold maintained a rounded morphology and could secrete the extracellular matrix on the porous scaffold. Conclusion The layered cylindric collagenhydroxyapatite composite scaffold has a good cellular compatibility, and it is ber in the mechanical property than the pure collagen. It will be an ideal scaffold for the cartilage tissue enginee ring.
Objective To investigate aesthetic outcomes and postoperative complications of hydroxyapatite particulate artificial bone for repairing sunken deformation of frontal bone following removal of dermoid cyst. Methods From February 2000 to May 2005, hydroxyapatite particulate artificial bone was used to repair the sunken deformation of frontal bone in 13 cases (9 males and 4 females), and the age of the patients was from 17 to 41 years. The dermoid cysts were all found during infant period, and the length and width of the cysts ranged from 6 cm×4 cm to 10 cm×8 cm. Anincision along the hairedge or tumor margin was made to excise the dermoid cyst in the forehead. After complete removal of dermoid cyst, the sunken frontal bone was examined and repaired with hydroxyapatite particulate artificial bone. The clinical checkup and Xray examination were utilized to determine aesthetic outcomes and postoperative complications at 1 week, 1 month and 6 months after operation. Results The primary wound healing was obtained in allpatients postoperatively, and no complications such as hematoma, infection, recurrence of dermoidcysts or displacement of hydroxyapatite particulate artificial bone were observed. With a followup from 1 to 20 months, all sunken deformations were completely repaired with satisfactorily aesthetic outcomes. Through clinical checkup and X-ray examination, the implants were found to integrate with the frontal bones without any gaps and displacement. Conclusion It is a simple and viable method torepair sunken deformation of frontal bone with hydroxyapatite particulate artificial bone.