A medium which detects H₂S produced by bacteria was newly designed by Onisi and Tachibana, being consisted of agar 2%, peptone 2%, meat extract 1%, NaCl 0.2%, sodium thiosulf ate 0.008%, sodium sulfite 0.04%, lead acetate 0.3%, glucose 0.1%, adjusted at pH 6.8. Dental scrapping from 195 apparently healthy tooth surfaces, and from 112 cavities, and pathological exudates from 150 pyorrhea pockets were inoculated in the media in order to find incidence of H₂S activity of these three different categories of specimens.
The positive reaction was found at 86.7% of pyorrhea specimens, at 66, 9% of cavity deposits and at 60% of healthy scrappings. The differences between pyorrhea and the rest were estimated to be significant.
The positive cultures were been plated on the same medium to identify the organisms corresponding to the H₂S production there in, i.e., 29 Veillonella, 7 Escherichia, 4 Bacteria, 5 Neisseria, 6 aerobic Micrococci, 2 anaerobic Micrococci, 2 Kurthia, one Corynebacteria and one Diplococcus were resulted, but neither Fusobacteria nor Treponema which may possibly major H₂S producers in the pyorrhea pocket. Veillonella, the majority of the genera showing positive reaction, Gram negative rods, the most intensive producers of H₂S, Fusobacteria and Treponema would be summarized to be dominant genera of H₂S production in the case of pyorrhea alveolaris. As the relation between pyorrhea and bacterial hydrogen sulfide, it is considered that the reducing action of the latter may affect the keratin layer of the gingival epithelium to create the S-S linkage in it.