As a home-visit nurse, I’ve come to appreciate the importance of oral care through daily practice.
In both caregiving and nursing settings, the value of maintaining good oral hygiene is being reevaluated.
In 2024, Japan’s long-term care insurance system introduced a new reimbursement category called the “Oral Care Collaboration Enhancement Add-On,” encouraging collaboration between dental professionals, nurses, and caregivers to improve the quality of care and enhance the quality of life for elderly individuals.
In previous blog posts, I’ve introduced swallowing support products such as thickening agents and the K-spoon that help fulfill the desire of many older adults to “keep enjoying food.” (The English version of that post is currently in preparation.)
But before we can protect someone’s ability to eat, we need to keep their mouth healthy. That makes daily oral care essential.
This article focuses on oral care gels—products used to moisturize the mouth.
I’ll highlight a patent for an oral care gel containing green tea catechins and share insights from real-world use, along with observations on current and future needs.
What Is an Oral Care Gel?
Oral care gel is a moisturizing agent used to hydrate the inside of the mouth.
In practice, it’s typically applied using a sponge brush or a gloved finger.
It’s commonly used for people with reduced saliva production, including:
- Older adults
- Cancer patients undergoing treatment
- Individuals unable to eat by mouth
Dry mouth not only causes discomfort and increases infection risk but also interferes with eating and speaking.
Compared to simply moistening with water, gels provide longer-lasting hydration and help stabilize the oral environment.
For those who cannot rinse their mouth, the gel can also be applied over crusted debris to soften it, making it easier to wipe away gently.
This type of care is widely practiced in nursing and long-term care settings.
A Patent for a Catechin-Containing Oral Care Composition
International Publication No.: WO2016/208582
Publication Date: December 29, 2016
Issue Date: April 5, 2018
Title: Oral Care Composition for Cancer Patients
This patent covers a green tea catechin-based oral care gel developed specifically for patients undergoing cancer treatment.
Problems with Earlier Solutions
Cancer treatments such as chemotherapy and radiation are known for their severe side effects.
One often-overlooked complication is oral mucositis—inflammation and ulceration of the oral mucosa—primarily caused by the generation of free radicals within the body during treatment.
Free radicals are unstable molecules that steal electrons from surrounding molecules, damaging lipids, proteins, and DNA through oxidative stress.
Since oral mucosa cells have high metabolic activity and are frequently replicating DNA, they’re particularly vulnerable. Damage during DNA replication can lead to cell death, inflammation, and ulcer formation.
Cancer treatments also impair salivary gland function, reducing saliva production. Saliva has both cleansing and antioxidant properties, helping protect mucosal tissue.
These factors combine to make the oral mucosa especially susceptible to damage and inflammation during cancer treatment.
While gargling can help, it comes with limitations:
- It must be performed every 2–3 hours to be effective
- Catechin-based rinses often have strong bitterness or astringency that can trigger pain
- Patients with swallowing difficulties may be unable to gargle safely
The Patent’s Solution
The patented formulation combines three key components:
- Green tea extract (catechins)
- Thickening polysaccharides
- Humectants (moisturizing agents)
This combination aims to prevent or reduce oral complications in patients undergoing cancer treatment.
Green Tea Catechins (EGCG)
Among the various catechins, epigallocatechin gallate (EGCG) is especially known for its potent antioxidant effects.
EGCG molecules contain multiple -OH (hydroxyl) groups that release hydrogen atoms, which stabilize free radicals.
Image source:https://www.funakoshi.co.jp/contents/5687
Although donating hydrogen might seem destabilizing, EGCG’s aromatic benzene rings exhibit resonance structures, dispersing electrons across the ring and maintaining molecular stability.
Image source: Aromatic Compounds (The benzene ring exhibits resonance structures and a delocalized electron cloud. The π electrons are spread across the entire ring, providing electron dispersion and stability.)
With multiple hydroxyl groups, a single EGCG molecule can neutralize several free radicals.
Thickening Polysaccharides
Xanthan gum, a naturally derived polysaccharide, is a key thickener used in the formulation.
Image source：Wikipedia
Its structure consists of a glucose backbone with mannose and glucuronic acid side chains. Numerous hydrophilic functional groups interact with water to form a mesh-like gel network.
This gel structure provides both moisture retention and viscosity, helping the gel stay in place on affected tissue.
Xanthan gum is also near-neutral in pH and gentle on inflamed mucosa, making it suitable for medical use.
Humectants
The patent highlights glycerin and propylene glycol as preferred moisturizing agents.
＜Glycerin ＞
Image source：Wikipedia
＜Propylene glycol＞
Image source：Wikipedia
These compounds contain multiple –OH groups that form hydrogen bonds with water, helping retain moisture and prevent mucosal dryness.
Practical Use of Catechins in Care Settings
During a clinical placement, a nursing student once suggested using green tea for oral care because the patient didn’t like brushing their teeth.
The student said, “He doesn’t like the taste of toothpaste, so I thought something familiar like green tea might make him more comfortable.”
The patient responded positively to the familiar aroma of green tea and allowed the care.
The student even researched commercially available green tea-flavored oral gels—demonstrating how everyday ingredients can support care.
New Possibilities for Oral Care Gels
Oral gels are typically used for moisturizing and cleansing, but I’ve also come to recognize their potential psychological value.
Even among elderly patients with swallowing disorders who can’t eat by mouth, many still express a strong desire to eat.
In home and facility settings, we often try to honor these wishes—sometimes offering small tastes of coffee or alcohol, though these come with aspiration risks.
One patient I cared for frequently asked to eat.
When I gave him an oral care gel, he enjoyed it so much he started calling it “candy.”
Perhaps its sweetness and texture reminded them of syrup or hard candy.
Because gels carry a lower aspiration risk, they can provide both hydration and sensory enjoyment.
In this way, oral care gels can support not just comfort, but dignity and pleasure.
Most commercial gels are sweet or mint-flavored, with few other options.
Still, flavors familiar to older adults—like green tea, roasted tea, savory broth, yuzu, or red bean paste—could be more appealing in care settings.
Personal Experience
Until recently, most available flavors were fruit-based or sweet.
When a coffee-flavored gel became available, I offered it to my mother, who is under my care. She loved it.
Image source:https://www.monotaro.com/g/07479996/
I tried it myself and found it tasted like a mildly sweet coffee-flavored candy.
My mother now uses flavored gels during the day and switches to unscented ones at night.
Important Safety Note
⚠ Oral care gels are not food.
Always use caution when applying them to the mouth, especially in patients with swallowing difficulties. These products are intended solely to moisturize the oral cavity.
Closing Thoughts
Oral care gels can do more than moisturize—they can support emotional well-being by addressing the desire to taste and enjoy.
As a nurse working in home care, I aim to continue sharing practical, evidence-based insights into care products and technologies that truly help in the field.
If you’re involved in developing or promoting care products and want feedback based on real-world use, feel free to get in touch via the contact form.
I’m happy to provide product impressions, usage examples, or field-based recommendations as needed.
References
Yu Kinbara (2009). Safe, Reliable, and Comfortable Nursing Manual for Cancer Chemotherapy. Igaku-Shoin.
John E. McMurry; Translated by Toshiaki Ito, Miaki Kodama, Toshio Ogino, Yoshimasa Fukazawa, Motuo Tooru (2013). Organic Chemistry Vol. 2 (8th Ed.). Tokyo Kagaku Dojin.
WO2016/208582 (2016, Dec. 29). Oral Care Composition for Cancer Patients. Meiji Co., Ltd.
National Library of Medicine: https://pmc.ncbi.nlm.nih.gov/articles/PMC6247744/?utm_source=chatgpt.com
Shizuoka Tea Industry Association: https://shizuoka-cha.com/index.php/ocha/science/%E2%91%A8%E8%8C%B6%E3%82%AB%E3%83%86%E3%82%AD%E3%83%B3%E3%81%AE%E6%8A%97%E9%85%B8%E5%8C%96%E3%81%AE%E6%A9%9F%E6%A7%8B%E3%82%92%E6%8E%A2%E3%82%8B/
Ministry of Health, Labour and Welfare: https://www.mhlw.go.jp/topics/2006/11/dl/tp1122-1l11.pdf
Food Development Lab: https://shokulab.unitecfoods.co.jp/
