Effect of two antimicrobial rinses and oral prophylaxis on preoperative degerming of saliva

Two degerming mouthrinses, a 1% povidone-iodine and a 0.2% aqueous solution of chlorhexidine gluconate, were tested with regard to their degerming effect on the saliva. The study comprised two parts. In the first part 19 dental students with good oral hygiene rinsed their mouths at weekly intervals with 10 ml of the povidone-iodine and 10 ml of the chlorhexidine solution. A control group of 12 students and nurses with healthy teeth and gums rinsed their mouths with 10 ml of plain water. In the second part 11 adult patients with periodontal disease used the two test rinses at weekly intervals both before and after periodontal prophylaxis including scaling of the teeth. Non-stimulated saliva was simpled immediately before and 5, 30, 60, and 120 min after each rinse. Part of the saliva was cultured on blood agar plates to show the growth of aerobic microbes. The remainder of the saliva was poured over a Dentocult dip-slide for determination of the number of acidophilic bacteria. The results showed that in the water control group the bacterial count increased in spite of the rinse. When compared with the prerinse values, both test rinses clearly reduced the amounts of bacteria. Chlorhexidine reduced the bacterial count 5 min after the rinse about one logarithm more than povidone-iodine, did, and the degerming effect of chlorhexidine was also of longer duration than that of the povidone-iodine solution. The periodontal prophylaxis in the adult group did not seem to lower the pre-rinse bacterial counts but did slightly improve the duration of the effect of both test solutions. The dip-slide tests showed that 28% of the subjects had no growth of acidophilic bacteria. This absence was not dependent on the other bacterial flora of the saliva. In the cases with a positive dip-slide test, the number of acidophilic bacteria decreased with both test solutions according to the pattern revealed by the blood agar plate cultures.