Effect of extraction of partly erupted third molars on salivary microbial counts in conscripts.

Viable counts of mutans streptococci, lactobacilli and yeasts in saliva were followed for 5 months after extraction of partly erupted third molars in 49 conscripts aged 19.9 +/- 0.8 years. For controls, 27 conscripts aged 19.7 +/- 1.2 years were studied who did not have indications for third molar extractions. The microbiological analyses were made from paraffin-wax-stimulated saliva using dip-slide techniques. The results showed a statistically significant reduction of the high counts of mutans streptococci (greater than or equal to 10(6) CFU/ml saliva) and lactobacilli (greater than or equal to 10(5) CFU/ml saliva), both 2 and 5 months after extraction, when compared with the baseline values and with the controls. The extraction of partly erupted third molars did not appear to affect salivary yeast counts. We suggest that partly erupted wisdom teeth act as reservoirs for mutans streptococci and lactobacilli, in particular, and that their state of eruption must be taken into account when interpreting salivary microbiological counts.