In addition to being the most popular beverage consumed other than water, tea—particularly green tea—has some surprising oral and overall health benefits.¹ Green tea has proven protective effects against malignancies, cardiovascular issues, and metabolic disorders. It has also been suggested to promote oral health by reducing inflammation and caries due to its antioxidant and antimicrobial properties. It can even be used to treat chronic systemic diseases, such as carcinoma.² Derived from the Camellia sinensis plant in China and Southeast Asia, green tea consumption has been a common practice for more than 2,000 years.¹ As preventive oral health care continues to expand, dental hygienists are increasingly exploring evidence-based natural adjuncts like green tea that may improve patient outcomes.

Oral health benefits

Reports have shown that drinking green tea regularly may decrease dental caries. Green tea leaves contain high concentrations of fluoride, contributing to its cariostatic action. However, studies report that its anticariogenic action is primarily due to a high concentration of polyphenols, such as epigallocatechin-3-gallate (EGCG).³ These catechins can strongly inhibit sugar transport and acid production, consequently preventing bacteria from adhering to the tooth surface. Studies have documented that drinking green tea daily for one month can increase the salivary pH to above 5.5.² A separate study concluded that rinsing with green tea mouthwash for one week significantly reduces the salivary levels of Streptococcus mutans and Lactobacillus. Green tea extract reduces a-amylase activity in the saliva, acting as an anticariogenic agent. Frequent green tea intake can significantly decrease caries formation, even with sugar present in the diet.⁴ Beyond its role in caries prevention, green tea may also improve other common oral conditions encountered in dental practice.

Halitosis is a common patient concern, mainly caused by volatile sulphur compounds (VSCs) produced by decaying microbial organisms. Tea catechins reduce the production of methyl mercaptan, one of the major VSCs. Green tea mouthwash containing 1% tannin can reduce the microbial load in the oral cavity, preventing plaque formation and improving halitosis.² This is likely why some products for bad breath treatment contain tea polyphenols, such as chewing gum and mouth spray.¹ Green tea may help reduce oral malodor and microbial load due to its polyphenol content.

Green tea catechins are known for their antioxidant properties providing protection from oxidative stress and cigarette smoke induced inflammation. Smoke from tobacco induces the production of superoxides and reactive nitric oxides, resulting in chronic inflammation of the tissues. Green tea can reduce gingival oxidative stress by scavenging extracellular nitrous oxide and superoxide, preventing the production of peroxynitrite.¹ Another smoke compound, acrolein, prevents gingival fibroblasts from functioning normally leading to various inflammatory conditions and increasing the progression of periodontal disease. It has been hypothesized that the green tea catechin EGCG reduces the toxicity of acrolein along with other aldehydes. Green tea can even be useful for patients trying to quit smoking, as the L-theanine found in green tea promotes relaxation and reduces stress. It can also help restore the oxidant-antioxidant imbalance in former tobacco smokers.²

Green tea has also been reported useful for preventing periodontal disease progression through its antioxidant and anti-inflammatory properties in the gingival crevicular fluid. Drinking green tea regularly can help decrease gingival bleeding index and periodontal pocket depth while supporting periodontal healing. Some studies on older adults report beneficial effects of green tea gels or chips placed directly into periodontal pockets following scaling and root planing. In vitro studies have shown that green tea catechin inhibits the growth of several bacteria associated with periodontitis, including Porphyromonas gingivalis and Prevotella intermedia. EGCG can also inhibit the formation of osteoclasts and induce cell death of osteoclasts, contributing to improved periodontal health.⁴

Tea polyphenols have been proven to be a promising agent in oral cancer treatment in both mice and human studies. This is due to their ability to prevent oral premalignant lesions from becoming malignant and by induction of apoptosis and disruption of the mitochondria of cancer cells without disturbing normal cells. Tea polyphenols may also protect against radiation-induced damage.² One study suggested that rinsing with 5% green tea mouthwash at least twice daily significantly improved the oral health status of patients with oral cancer undergoing treatment. Despite the promising evidence of the benefits of green tea in preventing oral and other cancers, there is currently not enough evidence for a universal recommendation to drink green tea for cancer prevention. It is, however, considered to be a simple, natural, safe, and effective oral care intervention for patients undergoing cancer treatment or experiencing oral mucositis.⁵

Limitations and considerations

The growing body of evidence surrounding green tea demonstrates significant therapeutic potential. However, there are a few considerations. Excessive consumption of green tea can lead to disrupted sleep and decrease the amount of iron bioavailability from the diet. It is recommended that pregnant and breastfeeding women limit green tea consumption to one to two cups per day, as it can increase heart rhythm. A few studies have shown that aluminum can be present in green tea, which can cause neurological diseases with heavy consumption. Patients taking Warfarin should not drink green tea since it contains vitamin K. It can also increase the risk of bleeding when taken with aspirin because it prevents platelet clotting.² An in vivo study has also demonstrated that green tea polyphenols can lead to oxidative stress and liver toxicity at higher concentrations.⁴ Although many studies report promising findings, much of the current evidence includes in vitro studies or small clinical trials. Larger long-term randomized clinical studies are still needed to fully understand the oral health benefits of green tea and how it could be used as an adjunct for oral health care.

Conclusion

Green tea can easily be incorporated into a dental hygienist’s patient recommendations, particularly for patients with concerns about halitosis or periodontal inflammation. If the patient prefers not to drink green tea, they could use it as a mouthrinse instead. It is important to educate patients about caffeine and potential medication interactions, including blood thinners. Patients should also be educated about how adding sugar or other sweeteners to green tea could be counterproductive. Lastly, reinforce that green tea complements, rather than replaces, traditional oral care. Regular oral hygiene practices and routine hygiene visits are still required for optimal oral health. Nevertheless, adding a cup of green tea is an easy habit that many patients may be willing to incorporate into their daily routine.

Further reading: Why nutrition counseling is a powerful clinical tool

Editor's note:

This article appeared in the July 2026 print edition of RDHmagazine. Dental hygienists in North America are eligible for a complimentary print subscription. Sign up here.