The effect of water on morning bad breath: a randomized clinical trial

Objectives: To assess the effects of water on the parameters of ‘morning bad breath’ (MBB) and to evaluate whether there is a difference between rinsing with water and drinking a glass of water.
Materials and methods: A total of 50 participants were recruited and were randomly divided into two equal groups. One group rinsed with 15 ml of water for 30 s, and another group drank 200 ml of water within 30 s. Clinical assessments were carried out during one visit between 7:30 am and 12:00 pm. Pre- and post-intervention measures were assessed organoleptically as primary outcome parameters, and a secondary outcome parameter was assessed using both the Halimeter® and OralChroma™ apparatuses to evaluate volatile sulphur compounds (VSCs), hydrogen sulphide (H2S), methyl mercaptan (CH3SH) and dimethyl sulphide ((CH3)2S). In addition, the presence of tongue coating (discoloration/thickness) and tongue fissures was assessed.
Results: All 50 participants completed the study. In both groups, a significant reduction in the organoleptic score and the OralChroma™ H2S and CH3SH readings was obtained after the intervention. Both regimens resulted in a CH3SH reduction of approximately 60%, whereas the reduction in H2S was between 30% and 50%. The acceptable change between pre- and post-assessments of the clinical parameters was not significantly different between the drinking and rinsing groups.
Conclusion: Rinsing with water or drinking a glass of water had a statistically significant effect on the MBB parameters. No significant difference was obtained between the two regimens.