The effects of a chlorhexidine mouthrinse on culturable microorganisms of the tongue and saliva.

A randomized and cross-over design clinical study with normal adult volunteers examined the effects of a 0.12% chlorhexidine (CHX) mouthrinse and a control rinse on a range of microflora including those implicated in halitosis on the tongue and saliva. Saliva and tongue scrapings were collected from 13 subjects prior to treatments with additional samples collected at 3 h post-treatment cultured on media to enumerate anaerobic, Gram-positive and Gram-negative bacteria, odorigenic bacteria producing hydrogen sulphide (H2S) and oral bacteria with proteolytic activity. In comparison to the control, rinsing with CHX demonstrated statistically significant reductions that ranged from 81-90% for tongue microflora with a 89-95% decrease noted on salivary flora (p<0.05). The effects of CHX on anaerobic, Gram-positive and Gram-negative bacteria are in accord with those noted on odorigenic bacteria producing H2S or proteolytic activity. These results help to explain previous clinical results on the malodor efficacy of CHX and highlight microbiological approaches for bacteria implicated in malodor.