Objective To screen common oral bacteria which produce hydrogen sulfide, and expect to find the main source of bad breath. To analyze the relationship between halitosis and oral caries, periodontal diseases. Methods Based on the color reaction between hydrogen sulfide and lead acetate, we use indirect experimental method by cotton-wool to detect 8 bacteria as Streptococcus, Actinomyces, Lactobacillas which are about caries and 9 bacteria as Porphyromonas, Prevotella, Fusobacterium which are about periodontal to identify the ability to produce hydrogen sulfide. Results All of the 9 bacteria about periodontal disease can produce H2S. In the bacteria group about caries, only Streptococcus gordonii, Actinomyces naeslundii, Actinomyces odontolyticus, Lactobacillus acidophilus can produce H2S while Streptococcus mutans, Streptococcus sobrinus, Actinomyces viscosus, Lactobacillus fermentatae can not. Conclusion Most of the bacteria which can produce H2S are gram-negative anaerobic bacteria. The bacteria that produce halitosis have relationship with the occurrence and development of periodontal disease, pulposis. And almost one half of the cariogenic bacteria can produce hydrogen sulfide, which can result halitosis.
