Objective The disinfection efficiency of a compound disinfectant spray with trichloro hydroxyl diphenyl ether on dental impression and plaster model, which have been contaminated by pathogens, were evaluated in this study. Methods As experimental group, germ-free alginate impressions and plaster models were sprayed with the compound disinfectant of different density trichloro hydroxyl diphenyl ether or indophors for 5, 10 and 15 min, after which were smeared with five tested pathogens, including Staphylococcus aureus, Escherichia coli, Saccha - romyces albicans, Streptococcus mutans and black spore variants of Bacillus subtilis. The colonies were counted after sampling, inoculate and culture, which were used to deduce the killing logarithm value as the standard of the disinfecting efficiency. Results The compound disinfectant spray with 3 000 mg·L-1 trichloro hydroxyl diphenyl ether was effective to all tested pathogens for 10 min whatever on the impressions or the plaster models. The disinfectant spray with same concentration was more effective on the alginate impression than on the plaster model in the same time（P＝0.000）. Conclusion The compound disinfectant spray with trichloro hydroxyl diphenyl ether is an effective antiseptics for alginate impressions and plaster models.
