Effectiveness of green tea mouthwash for improving oral health status in oral cancer patients: A single-blind randomized controlled trial

Background: Painful oral mucositis or trismus, caused by cancer therapy, reduces patients' willingness to maintain basic oral hygiene and eventually results in a poor oral health status. Using mouth rinses and cleaning the tongue are popular ways to improve the oral health status. Objectives: To evaluate the effectiveness of green tea mouthwash for improving the oral health status in oral cancer patients undergoing cancer treatment. Design: This was a prospective, single-blind, randomized, controlled trial. Settings: Patients were recruited from a major regional teaching hospital that provides specialist cancer care services in Chia-Yi, Taiwan, from July 2018 to June 2020. Participants: A total of 63 patients met the following criteria: > 20 years old; newly diagnosed with oral cancer by a physician; treated with oral surgery within one month prior; and completion of follow-up, with or without chemotherapy or radiation therapy. The exclusion criteria were mental illness; an acute and severe illness; complete edentulism; and inability to open the mouth more than 1 cm. Methods: Patients were randomly assigned to 2 groups: the mouthwash with green tea (intervention) group or the tap water (control) group. After each teeth-brushing procedure, those in the intervention group rinsed the mouth with 100 ml of a green tea solution for 60 seconds, and those in the control group rinsed the mouth with 100 ml of tap water for 60 seconds. The primary outcome was the oral health status, which was evaluated according to the Oral Assessment Guide and measured at baseline and at every monthly outpatient follow-up until six months by the same nurse. Results: There were 31 subjects in the intervention group and 30 subjects in the control group in the final analysis. The results of t-test showed that compared with baseline, the improvement in the oral health status in the intervention group was significantly better than that in the control group at 4 months after the intervention began. At 4 to 6 months after the intervention began, the oral health status score in the intervention group significantly decreased, by 1.71, 2.97 and 2.93 points, respectively, compared with that in the control group. Conclusions: The oral health status can be improved and maintained for a long time with the continuous use of green tea mouthwash. Green tea mouthwash is a simple, natural, effective and safe intervention that should be recognized as a nonpharmacological treatment option for protecting the oral mucosa. Trial registration: clinicaltrials.gov identifier NCT04615780 (c) 2021 Published by Elsevier Ltd.