Objective The purpose was to analyze the effects of three sterilization methods（ dry heat sterilization, steam sterilization, chemical sterilization） on the corrosion of dental fissure burs. Methods 100 dental fissure burs were distributed to 10 groups. One was control, the burs in the other 9 groups were treated by dry heat sterilization, steam sterilization, chemical sterilization with 5, 10, 15 cycles respectively. Weight method， scanning electron microscope, micro- hardness measurement were used to analyze the corrosion of dental fissure burs. Results The fissure burs gained their weight with cycles of sterilization. 5, 10, 15 cycles of dry heat sterilization, 10, 15 cycles of steam sterilization and 15 cycles of chemical sterilization, the weight of fissure burs were significantly increased （ P0.05）. Conclusion The corrosion is most severe in steamsterilization group, followed by chemical sterilization, dry heat steriliza -tion. Dry heat sterilization shows less corrosion.
