The Influence Of Related Oral Pathogenic Bacteria On The Surface Of Four Kinds Of Alloys

Objective:Four kinds of alloys, nickel chromium alloy, cobalt chromium alloy, Gold platinum alloy and palladium silver alloy, were used to compare the influence of streptococcus mutans and candida albicans on their surface roughness and glossiness in oder to explore the mechanism of corrosion and discoloration of oral related bacteria on alloys and to provide theoretical support for the development of new materials.Methods:Each of 9 standard specimen was made of 4 kinds of alloys, and then was grinded and polished smoothly accoding to the sme procedure. After being sterilized they were anaerobic cultured in the BHI( Brain Heart Infusion Broth, BHI)containing streptococcus mutans and candida albicans for 4 weeks. After that the changing of surface roughness and gloss each speciman was detected by UV(ultraviolet spectrophotometer,UV) and AFM(atomic force microscope,AFM).Results:For the changing of surface roughness, the largest one was nickel-chromium alloy(p<0.01), and then was cobalt-chromium alloy(p<0.05), while the other two,gold platinum alloyand silver palladium alloy(p>0.05), only slightly changing could be observed and had no statistic difference(p>0.05).For the changing of surface gloss, the reflectance of nickel chromium alloy and cobalt chromium alloy was significant, and the gloss was also obviously decreased, while the gold platinum alloy and silver palladium alloy had slightly changing.Conclusion:The surface roughness and glossiness of alloys is decreased due to the effect of bactiara, which can lead to discoloration of alloys in the condition of this study.