The Related Biological Performance Evaluation Of Co-Cr Alloy Fabricated By Laser Rapid Forming

Cobalt-chromium alloy is one of the most widely used oral alloys in China because of its high biocompatibility, fatigue durability, and mechanical strength, and low price. However, the traditional investment casting for metal dental prostheses can no longer fulfill the requirements of doctors and patients for the fastness and automation of prosthodontic treatments. As a new metal fabricating technology, Laser Rapid Forming (LRF) overcomes the shortcomings of traditional technique and significantly improves the efficiency of the production of dental prosthesis and its quality.Objectives:Fabricate Co-Cr alloy by Laser Rapid Forming (LRF) technique and to test the biosafety and biocompatibility of it; to provide a theoretical reference for the clinical application of Co-Cr alloy fabricated by LRF; to give a choice for the manufacturing of additive materials.Methods:1.Co-Cr alloy powder was fabricated by laser steric forming system (Laser power:2000W; Scanning rate:300mm/min; Powder feeder rate:6.5g/min; Spot diameter:3mm). Hemolytic test, short-term systemic toxicity test, cytotoxicity test and oral mucous membrane irritation test were conducted based on to test the biosafety of LRF-fabricated Co-Cr alloy.2.Primary osteoblasts were cultured with the application of the rat cranium and modified tissue culture, and purified and passaged. The maturity of OBs was tested through the cell morphology and alkaline phosphatase (ALP) dyeing.The osteoblasts were seeded on the surface of LRF-fabricated Co-Cr alloy and casted Co-Cr alloy (control group) and cultured in vitro. The adhesive capacity of the osteoblast to the two materials was observed. The ALP activity was examined and test of cells proliferation by CCK-8. The morphology of the osteoblasts was observed with scanning electron microscope.Results:1.The hemolytic rates of LRF-fabricated Co-Cr alloy was0.8%. The short-term systemic toxicity test, cytotoxicity test and oral mucous membrane irritation test did not show systemic toxicity or cytotoxicity or oral mucous membrane irritation of LRF-fabricated Co-Cr alloy.2.The observation of the morphology of primary osteoblasts and the positive results of subculture training osteoblasts dyeing experiments of alkaline phosphataseshowed that the osteoblasts cultured in vitro had the morphological and biological features which normal osteoblasts have.No significant differences were detected in the tests of adhesive capacity and cells proliferation. ALP activity express the most time increased gradually to increase. Osteoblasts spread and grew well and adhered firmly on the surface of LRF-fabricated Co-Cr alloy.Conclusion:The fabrication of Co-Cr alloy by LRF will not bring or produce toxic substance into it. Because of its high biosafety and biocompatibility, LRF-fabricated Co-Cr alloy is a good material for dental treatments.