RESUMO
BACKGROUND:Studies have confirmed that the nano-hydroxyapatite/chitosan/alginate composite materials have a certain flexibility and strength and possess a bioactivity similar to human bone. OBJECTIVE:To explore the effect of the nano-hydroxyapatite/chitosan/alginate composite materials on the repair of rabbit mandible defects. METHODS:Bilateral mandibular defect models of 10 mm × 5 mm × 5 mm were made in 18 healthy New Zealand white rabbits. Then, the rabbits were divided into two groups:experimental group was implanted with nano-hydroxyapatite/chitosan/alginate composite material, and control group was implanted with hydroxyapatite/chitosan composite. At 4, 8 and 12 weeks after implantation, cone-beam CT was applied to observe implant degradation, cal us growth and bone connection in the defect area;new bone formation was observed by hematoxylin-eosin staining. RESULTS AND CONCLUSION:The gray values of the bone density in the experimental group and control group gradual y increased with time, and there were remarkably significant differences between the two groups at different time points (P<0.01). At the same time point, the experimental group was superior to the control group in gross observation, cone-beam CT observation, gray value of CT and histological observation (P<0.05). At 4-8 weeks after implantation, the implant materials in the two groups were gradual y degraded with a blurred junction between the defect and bone tissue, and a smal amount of new bone formed tightly integrated to the recipient bone tissue, in which the experimental group was more significant. And during 8 to 12 weeks, the degradation of implanted materials in the two groups was basical y complete, and the implant began to merge with the recipient bone tissue, with further generation of new bone tissue and gradual repair of bone defect area, in which, the experimental group was more obvious. Results show that the nano-hydroxyapatite/chitosan/alginate can repair bone defects effectively, and promote the new bone formation.
RESUMO
BACKGROUND:Physical structure and inorganic composition of composite calcium phosphate bone implants are similar to human bone, and the implants have good bioabsorbable ability and biocompatibility. Studies have confirmed that Dipsacus powder can significantly improve the speed of bone defect repair. OBJECTIVE:To study the effects of Dipsacus asperoides/composite calsium phosphate bone implant material in the repair of bone defects. METHODS:Bone defects of 1.0 cm×0.5 cm×0.3 cm were made on the bilateral mandibular bodies. The right side was implanted with Dipsacus asperoides/composite calsium phosphate bone implant as experimental group and the left side implanted with calcium phosphate bone material served as control group. Samples were col ected at 4, 8, 12 weeks after implantation for gross observation, cone beam CT, scanning electron microscope observation and histological observation. RESULTS AND CONCLUSION:(1) Gross observation:the osteogenic speed, degradation rate and hardness in the experimental group were higher than those in the control group. (2) Cone beam CT detection:the implant in the experimental group was more tightly integrated with the surrounding tissues than that in the control group, and the degradation speed in the experimental group was higher than that in the control group. (3) Scanning electron microscope observation:there were many fibrous connective tissues between the implants and the surrounding tissues in the two groups, which was more obvious in the experimental group than the control group. With time gone, the implants were combined with the surrounding tissues more tightly. (4) Histological observation:the osteogenic speed and activity in the experimental group were superior to those in the control group. These findings indicate that Dipsacus asperoides combined with composite calcium phosphate bone implant can accelerate bone repair.
