Objective:To observe the bacteriostatic efficacy of bromogeramine of different concentrations made with potassium alginate impression materials and their effect on the dimensional accuracy of impression materials.Methods:Based on the methods described in "Disinfection Technical Guidelines"(Ministry of Public Health of the People’s Republic of China)

impressions were mixed by bromogeramine with concentrations of 0.05%

0.1%

0.2%

0.4% and 0.6%

respectively.The bacteriostatic efficacy of impressions were evaluated through measuring the size of inhibition zone

and their dimension value of the corresponding landmarks were measured with a measuring microscope and statistically analyzed.Results:(1) The diameter of the inhibition zone was enlarged as the concentration of bromogeramine increased from 0.05% to 0.40%.It did not change when the concentration of bromogeramine was above 0.40%.Bromogeramine of any concentration had no effect on Pseudomonas aeruginosa.(2) Dimensional evaluation of the impressions with different concentrations of bromogeramine showed no significant difference in comparison with that of the control group(P>0.05)

respectively.Conclusion:Alginate impression material mixed with bromogeramine(0.40%) had some bacteriostatic effect on bacteria except pseudomonas aeruginosa

and it has no effect on the impression accuracy.It could be an ideal disinfection method for clinical use.