A 2021 study has revealed a surprising link between use of green tea mouthwash and improvement in oral health for oral cancer patients.
Green tea is a staple beverage, often consumed on a daily basis around the world. Enriched with antioxidant and anti-inflammatory properties, it is renowned for its extensive health benefits. However, its potential benefits have been overlooked beyond its dietary uses. Having gained little attention before, the first evidence is now emerging that green tea can improve oral health. A study conducted in Chai-Yi, Taiwan, assessed whether a green tea mouthwash can improve oral health in oral cancer patients from July 2018 to June 2020, unveiling a promising nonpharmacological treatment option for protecting the oral mucosa.
Oral mucositis, a condition characterized by inflammation, swelling and ulcerations of the lining of the mouth [1] (shown in Figure 1), is a significant side effect associated with high-dose radiotherapy and chemotherapy. Coupled with jaw spasms (trismus), which results from oral cancer surgery, both lead to restricted mouth opening and reduces patient’s willingness to maintain oral health, profoundly affecting the lives of oral cancer patients. Consequently, poor oral health can result in lowering treatment doses or stopping treatment unexpectedly, ultimately affecting patient prognosis.
Popular ways to maintain oral health include cleaning the tongue and using mouth rinses. Studies have generally demonstrated that treatment with mouthwashes in cancer patients provide superior benefits for oral mucositis. However, despite the use of conventional mouthwashes such as chlorhexidine, long-term use is not advised due to undesirable effects on the oral mucosa, including soreness, irritation and a general burning sensation.
METHOD
A new study conducted in Taiwan explored the potential benefits of green tea mouthwash in oral cancer patients undergoing treatment. It is well-known that almost all cancer patients undergoing cancer treatment can have poor oral health [3] and mouthwashes provide superior benefits for mucositis, but no research had been conducted investigating the effect of green tea mouthwash on oral health.
Sixty oral cancer patients who underwent various cancer treatments including surgery, radiotherapy or chemotherapy were enrolled in the study. The randomized, controlled trial design assigned participants either a 5% green tea mouthwash or tap water rinse (control) after brushing. The patients were selected based on the criteria that they were 20 years old, newly diagnosed with oral cancer and had undergone treatment with oral surgery within one month prior to the study. Measurements of oral health were then taken several times throughout the study period, including baseline assessment and then at monthly intervals until the six-month mark.
WHAT WAS MEASURED?
The primary outcome measured was the oral health status of patients, evaluated using the Oral Assessment Guide, which assesses various oral health parameter (shown in Figure 2) and each category was given a rating of 1 to 3, with 1 indicating normal and 3 indicating severe issues. The scores were taken to reflect overall health status.
Additionally, the study evaluated specific aspects of oral health by assessing subscales within each category and carried out observations, recording any changes in oral health over time. This included noting any improvements or deterioration in symptoms such as pain, inflammation, or oral functions such as swallowing or speech.
Category | Method of Administration |
Voice | Talk to patient |
Swallow | Ask patient to swallow |
Lips | Observe and feel tissue |
Tongue | Observe appearance |
Saliva | Observe consistency and quality of saliva |
Mucous Membrane | Observe tissue appearance |
Gingivae | Press tissue with gloved finger |
Teeth | Observation |
Figure 2: Eight categories of Oral Assessment tool used to assess oral health [4].
Among the 63 patients who qualified for participation, five patients were unable to complete follow-up sessions due to worsening conditions, leading to incomplete data. A further two participants were excluded from the analysis as they did not fulfill the minimum requirement of having three months’ worth of data for valid analysis. As a result, final data analysis was conducted on 31 participants in the intervention (green tea) group and 30 participants in the control group.
RESULTS
The results showed that the intervention group had significantly improved oral health across various categories when compared to the control group, particularly after the fourth month of treatment. Significantly lower mean scores, which indicated better oral health, were recorded in the intervention group at the fourth month of treatment (T4). At T4, the intervention group showed an average improvement of 4.1 points compared to their baseline. In contrast, the control group only showed an improvement of 2.3 points from baseline. This trend continued in month five and six of treatment (T5 and T6 respectively). By the end of the T6, the intervention groups’ oral health status improved further, their oral health score decreasing (improving) by 9.3 points, while the control groups’ score decreased by 6.6 points.
The subscale scores, apart from voice and swallowing also showed significant improvement when comparing baseline to T5 and T6. The subscale scores for lips, tongue, saliva, mucous membranes, gingiva and teeth or dentures were significantly lower in the intervention group than in the control group, indicating improvements in oral health in several different aspects.
DISCUSSION
Few studies have looked at nonpharmacological treatments for protecting the oral mucosa. The study conducted by Liao et al and colleagues presents evidence for the first time that the use of green tea significantly improves oral health in oral cancer patients. The study found improvements across different subscales and patients reported improved mucous membranes, potentially facilitating the continuation of cancer therapy for patients.
Green tea has high polyphenol concentrations found and it possesses various biological properties. Polyphenols inhibit the growth and adherence of pathogens associated with the development and progression of periodontal diseases, the wide range of inflammatory conditions regarding the supporting structures of the teeth [5]. They have also been found to show potent anti-inflammatory properties, which can help reduce inflammation in the oral mucosa, alleviating symptoms and promoting healing. Highly regarded for their antioxidant properties, polyphenols also reduce harm from free radicals and reduce oxidative stress that can cause damage to the oral mucosa [6].
While the study has shown significant results, it is important to consider its limitations. The study was conducted in Taiwan and may not be an accurate reflection of other ethnicities, limiting its generalizability to other geographical locations. The study was also a single-center study which limits the findings to other populations and settings where there are different medical practices and healthcare resources. Nonetheless, the study does provide valuable insights into the potential benefits of green tea mouthwash in improving oral health in oral cancer patients. Further research, ideally on a larger and more diverse population, is needed to confirm the extent of these findings, ensuring broader applicability.
References:
Liao, Y.-C., Hsu, L.-F., Hsieh, L.-Y. and Luo, Y.-Y. (2021). Effectiveness of green tea mouthwash for improving oral health status in oral cancer patients: A single-blind randomized controlled trial.
[1] Bell A, Kasi A. Oral Mucositis. [Updated 2023 May 29].
[2] Lalla, R. V., & Peterson, D. E. (2005). Oral mucositis
[3] Aoki, T., Kudo, M., Endo, M. et al. Inter-rater reliability of the Oral Assessment Guide for oral cancer patients between nurses and dental hygienists: the difficulties in objectively assessing oral health.
[4] Gibson, F., Cargill, J., Allison, J., Begent, J., Cole, S., Stone, J. and Lucas, V. (2006). Establishing content validity of the oral assessment guide in children and young people.
[5] Kinane, D. F., Stathopoulou, P. G., & Papapanou, P. N. (2017). Periodontal diseases.
[6] Chacko, S. M., Thambi, P. T., Kuttan, R., & Nishigaki, I. (2010). Beneficial effects of green tea: a literature review
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