Preparation of novel bulk carbon nano tubes dental materials for implant / 中国组织工程研究

ABSTRACT

BACKGROUND: Carbon nanotubes (CNTs) is about 1 mm in diameter and about 1-10 μm in length cylinder-like material, and it only contains the spiral of carbon atoms arranged on the surface. Because of its unique tubular structure, lower density than that of graphite and with a high enough intensity, CNTs are expected to substitute bone.OBJECTIVE: To primarily study the influence of the content of polycarbosilane (PCS) and the sintering pressure on CNTs, look for the most optimum condition for the preparation of chunk CNTs, analyze the physical properties and biocompatibility of the material, and provide a choice for candidate implant denture material.DESIGN: The content of cement and the sintering pressure are adjusted in the experiment to make sure the most optimum condition for the preparation, and the capabilities of the material are observed and analyzed to make sure if that the material is suitable for implant denture.SETTING: Department of Stomatology, Xiangya Hospital, Central South University; Prosthodontics Staff Room, Oral Medical College of Central South University. MATERIALS: 80% pure molecules of CNT (Nano Lab Company USA), 20-40 nm in diameter, 5-20 mm in length, was provided by Nacheng Technology Development Corporation of Beijing. PCS was compounded by 502 Development Room of Defense Technology University, and the molecular weight is 1 300; Ten male white Wistar rats with 8 weeks old were provided by Animal Experiment Center of Guangxi Medical University. The treatments with the animals accorded to animal ethical standard in the experiment.METHODS: The experiment was carried out in the Experimental Center of Material College, Central South University from January to August 2005. By using the spark plasma sintering (SPS), at the sintering temperature of 1 200 ℃, the pressure from 20 MPa to 60 MPa, PCS was used as the cement to produce the new chunk multi-wall CNTs.MAIN OUTCOME MEASURES: By using Archimedes method and adsorption of gases method, Japanese MitutoyoHM-101 little burden Vickers hardness meter was used to test the apparent bulk density, specific surface area, Vickers hardness at the different contents of PCS and sintering pressures. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to observe the microstructure of the material.RESULTS: ① Microstructure: SEM and TEM indicated that the nanotube structure of the material was retained after sintered. ② Conforming phase of material: X-ray diffractometer indicated that carbon nanotubes were felt by PCS pyrolysis product of SiC; along with the PCS content and sintering pressure increased, the specific surface area was reduced, and Vickers hardness and density increased. Specific surface area decreased. ③ Histological compatibility: The inflammatory reactions of the CNTs/PCS were little more serious along with the increase of the content of PCS. The physical property of carbon nanotubes was prepared in this way, it was closed to bone tissues, it had the better biocompatibility, and it was the suitable candidate implant denture material.CONCLUSION: Appropriate to PCS for the bonding agent, through SPS, at 1 200 ℃, 20-60 MPa sintering pressure, CNTs/PCS which the material property is closed to bone tissues can be prepared, and CNTs/PCS subcutaneous implantation in rats does not show significant rejection; therefore, it is suitable candidate for dental implants material.