A clinical and bacteriological investigation of dental pulps of non-carious teeth in various conditions was performed with following results.
1) No microorganism was found in dental pulps of 25 intact teeth.
2) Only 9 cases of 50 pyorrheal teeth yielded positiv cultures. Streptococcus viridans was found in 7 cases, and Staphylococcus albus in 2 cases.
3) In 7 cases of 36 lower 3 rd molars accompanied by pericoronitis, Streptococcus viridans was found.
4) Of 58 teeth in acutely inflamed area of jow bone, 32 teeth yielded positive cultures. Among them Streptococcus viridans was identified in 15 cases, and Staphylococcus albus in 17 cases. Namely a majority of the cases were infected.
In view of these results, it is conceivable that even though the teeth in acutely inflamed area of jaw bone are not carious, a majority of them will be possible sources of recurrence of inflammation or focal infection. Therefore we have to watch them strictly, and they must be under timely treatment at a proper time.