Efficacy of 3% hydrogen peroxide solution in cleaning tongue coating before and after surgery: a randomized phase II study

BACKGROUND: Increased bacterial presence in the tongue coating and thereby, the saliva, may be a risk factor for postoperative complications such as surgical site infection or postoperative pneumonia after cancer surgery. However, no method for cleaning tongue coating has been established experimentally. The purpose of this study was to verify the effect of brushing with 3% hydrogen peroxide on suppression of the number of bacteria in tongue coating. METHODS: Sixteen patients with gastric cancer or colorectal cancer undergoing surgery were randomly allocated to control and intervention groups. In the control group, the tongue was brushed for 30 s with a water-moistened toothbrush, while in the intervention group, the tongue was brushed for 30 s with a toothbrush moistened with 3% hydrogen peroxide. Bacterial counts on tongue coating were measured before and 30 s after cleaning the tongue coating using the Rapid Oral Bacteria Quantification System. RESULTS: In the control group, the number of bacteria on the tongue did not decrease significantly after tongue cleaning on the day before surgery, but did on the day after surgery. In contrast, in the intervention group, the number of bacteria on the tongue decreased significantly after tongue cleaning both on the day before and the day after surgery. Furthermore, when comparing the control and intervention groups, the intervention group had a greater reduction effect. CONCLUSIONS: Tongue brushing with 3% hydrogen peroxide is a useful method to reduce the number of bacteria on the tongue in patients with gastrointestinal cancer undergoing surgery. Trial registration jRCTs071200020 (July 3, 2020).