The Composite Material Of Nano-hydroxyapatite And Heat-curing Resin: Plasticity And Biocompatibaility

Background:Hydroxyapatite(HA) is the main inorganic composition of bony tissue. It is a kind of biomimetic materials and has being widely used in clinical application and mostly synthesized artificially. It has an excellent bioactivity, biocompatibility, the property of osteoacusis and a similar mineral composition likes the nature demic bone and is considered as one of the most potential biomedical materials. It was been limited used in clinical application for the frangibility, lower intensity and short of tenacity. Except the property of HA,the Nano-hydroxyapatite(n-HA) has a great superiority in physico-chemical property and biology property and has being used in many fields extensively , such as department of orthopaedics, department of stomatology, plastic surgery , otorhinolaryngology , ophthalmology, and so on. It is not autologous tissue and has many advantaged fortes.Polymethyl Methacrylate (PMMA) is the main composition of heat-curing rasin, commonly called plexiglass, is a thermoplasticity material and has a good biocompatibility. The material of heat-curing rasin is cheap and easy to be processed, has being widely used in clinical application, such as medical equipment and artifcal teeth, being repaired bone defects of the cranial bones and the lower jaw bone and fixed artificial joint, and so on.At present, scholars around all over the world carry out plenty of study and research with the complexity artificial bone of HA. But it could not completely satisfy the requirement of clinical application for its bad mechanics efficiency,et al. Meanwhile, there is not any related report around all over the world about the n-HA and heat-curing resin composite materials. Therefore , first of all , we compouded the n-HA and the heat-curing resin together , enabled the composite materials expeditiously fixiform and solidify, and then imbeded on the surface of the bones of cranium of the SD rats (Subperiosteum) to observe the biocompati- bility ,ossify activity and Biological Security and provide experiment foundation for treatment of bone defecrts. To study the possibility of ossify activity after imbeding composite materials in corpore and provide theory evidence for being used in clinical application by the histology,the X-ray examination and SEM.Objectives: The n-HA and heat-curing resin composite materials were compared with the simple n-HA and silica gel to study the plasticity and biocompatibility and the possibility in bone defects repair , provide method foundation for being used in plastic surgery.Methods: As a test the n-HA and heat-curing resin composite materials were subjected to the acute whole body toxity test, the implantation test of the composite materials (on the surface of the bones of cranium of the SD rats ,Subperiosteum),and made use of the methods of the histology ,the X-ray examination and SEM to compare with the two control groups.Results: After intravenous injection and intra-abdominal injection of soaked solution of materials,there were no changes in breath,appetite,body weight of SD rats and no death. The composite materials have great plasticity. The X-ray examination and SEM show that the materials and the bone tissue were closely combine together. The result of the histology indicate that the n-HA and heat-curing resin composite materials have great biocompatibility and biological Security.Conclusion : The n-HA either has the property of the Nano-material,or has the property of the HA, has an excellent bioactivity , biocompatibility, osteoacusis and biological Security. It is a comparative ideal human-body sclerous-tissues replacement materials. The heat-curing rasins have good biological Security, asepsis,no side effect, no irritation to the organism and mucosae ,and have stable chemical function and good physical and mechanical function. It shows great plasticity after the n-HA and the heat-curing rasin recombining and improves the shortage of the simple n-HA and silica gel, fast syzygia with bone tissue and hope to become a comparative ideal material in bone defects repair of the cephalosome and prosopo.