Background: Breath odour is a complaint encountered worldwide, often linked to microbial overload in the oral cavity. This double blind, crossover, randomised study assessed the efficacy of several antiseptic mouthrinses or slurry vs. a control solution in the prevention of morning bad breath during an experimental period of 7 days without mechanical plaque control.
Methods: Sixteen dental students with a healthy periodontium abolished, after a thorough professional cleaning, all means of mechanical plaque control during five experimental periods of 7 days, interleaved by washout periods of at least 3 weeks. During each experimental period, as the only oral hygiene measure, the students rinsed twice a day with one of the following formulations (in a randomised order): a 0.2% chlorhexidine-alcohol mouthrinse (CHX-Alc), a 0.05% CHX + 0.05% cetylpyridinium chloride + 0.14% zinc lactate mouthrinse (CHX-CPC-Zn), an amine fluoride/stannous fluoride (125 ppm F-/125 ppm F-) containing mouthrinse (AmF/SnF2Mr), a slurry of a tooth paste (AmF/SnF2Sl) containing amine fluoride (350 ppm F-) and stannous fluoride (1050 ppm F-) and a placebo solution (placebo). At days 0, 3 and 7, morning breath was scored via VSC level measurements of the mouth air, and organoleptic ratings of the mouth air and tongue coating. At the same visits both the degree of gingival inflammation and the de novo plaque formation were rated. At the end of each period a questionnaire for subjective ratings was completed and microbiological samples were taken from the tongue dorsum, the saliva and the supragingival plaque for anaerobic and aerobic culturing.
Results: Although oral hygiene during the experimental periods was limited to rinsing, bad breath parameters systematically improved (P < 0.001) with the three mouthrinses (CHX-Alc, CHX-CPC-Zn, AmF/SnF2Mr), with a superiority of the CHX-CPC-Zn solution when only VSC values were considered (P < 0.003). The AmF/SnF2 slurry and the placebo solution showed only minor changes with time. The three mouthrinses reduced significantly (P < 0.001) the bacterial load (aerobic & anaerobic) in the saliva (>or= 0.5 log reduction with a superiority (P < 0.005) for the CHX-Alc when compared to the two others). Changes in the bacterial load on the tongue dorsum could only be detected for the CHX-Alc solution (0.5 log). The antibacterial effect of the placebo solution and the slurry were negligible. The composition of microflora on the other hand did not reveal significant changes. The de novo supragingival plaque formation was significantly (P < 0.05) inhibited by the three mouthrinses with a slight superiority for the CHX-Alc solution. The degree of gingival inflammation at day 7 remained low (< 0.16) for all products. The CHX-Alc solution scored significantly worse for the subjective evaluation (questionnaires) concerning taste and sensitivity of tongue).
Conclusions: The results of this study demonstrate that morning breath odour can be successfully reduced by the sole twice daily use of CHX-Alc, CHX-CPC-Zn or AmF/SnF2Mr mouthrinses, which all significantly reduced the bacterial load in the saliva and retarded the de novo plaque formation.