Minah GE et al. (1989)

EFFECTS OF 6 MONTHS USE OF AN ANTISEPTIC MOUTHRINSE ON SUPRAGINGIVAL DENTAL PLAQUE MICROFLORA¹

Objective

To determine whether long-term use of LISTERINE^® Antiseptic led to undesirable succession of oral pathogens or the emergence of resistant microbial forms.

Methods

This was a 6-month, randomized, double-blind, supervised, controlled study of 83 subjects with preexisting plaque and gingivitis. After a complete prophylaxis, subjects rinsed twice daily with either LISTERINE^® Antiseptic or a hydroalcohol control in addition to normal oral hygiene. Subjects were asked not to use any other mouthrinses during the study. Supragingival plaque was collected before and at either 3 or 6 months after treatment. Plaque samples were analyzed by dark-field microscopy, culture on a series of nonselective and selective bacteria media, and by recognition of microbial forms by recognition of distinct colony on a nonselective medium.

Results

At 6 months, the LISTERINE^® Antiseptic group revealed no alteration in the proportions of microbial species present in supragingival plaque and no emergence of resistant bacterial forms was found.

Conclusion

The microbiological evaluations of supragingival dental plaque demonstrated that long-term use of the antiseptic studied did not cause a meaningful shift in its microbial composition or emergence of presumptive oral pathogens. Additionally, it can be deduced from the results of this study that bacterial susceptibility to the antiseptic did not decrease since this would have led to a detectable microbial flora shift.