INVERSE CORRELATION BETWEEN THE PROPORTION OF SALIVARY BACTERIA INHIBITING STREPTOCOCCUS-MUTANS AND THE PERCENTAGE OF UNTREATED CARIOUS TEETH

To evaluate the role of inhibitory substances produced by bacteria in the oral cavity, we estimated, by a deferred test on Todd-Hewitt agar enriched with hemin and vitamin K, the proportion of bacteria that inh ibited or stimulated the growth of Streptococcus mutans and Porphyromo nas gingivalis, from the saliva of 109 patients (54 males and 55 femal es) attending our dental clinics. The patients, aged from 8 to 75 year s old (mean: 31 +/- 18 years), were randomly selected whatever the rea son for their visit. The results, evaluated with the Spearman rank tes t, indicated that there was no statistically significant (P > 0.05) co rrelation between the proportion of salivary bacteria inhibiting or st imulating P. gingivalis with the Community Periodontal Index of Treatm ent Needs (CPITN), the number of carious, missing and filled teeth, or with the decayed, missing and filled teeth index (DMFT). Also, no sta tistically significant correlation was observed between the proportion of salivary bacteria stimulating the growth of S. mutans and the abov e mentioned health indexes. However, a statistically significant (P < 0.005) negative correlation was found between the percentage of cultiv ated bacteria that inhibit S. mutans and the percentage of untreated c arious teeth as well as with the CPITN. The results thus indicate a po ssible role for inhibitory substances produced by bacteria in the main tenance of oral health.