Saliva-releasing gel may offer long-term relief for dry mouth sufferers

Dry mouth, or xerostomia, affects nearly one in three older adults. It happens when your salivary glands stop producing enough saliva, leaving your mouth feeling dry, sticky, and uncomfortable. This condition can make it harder to chew, swallow, speak, and even breathe easily. It also increases your risk of cavities and infections like oral thrush.

Xerostomia often shows up as a side effect of chronic illnesses or treatments like chemotherapy, radiation therapy, and hemodialysis. Some medications for depression, anxiety, and high blood pressure can also lead to dry mouth. Unfortunately, many of the current treatments don’t work well for long. Pills, sprays, and lozenges may help in the moment but fade quickly. Worse, some bring unpleasant side effects, including tooth erosion, gum irritation, and increased sensitivity.

That’s why researchers at Purdue University developed something new: a reusable saliva-releasing gel that could offer longer-lasting relief with fewer downsides. In a study published in ACS Applied Polymer Materials, the team revealed a small, soft hydrogel that stores artificial saliva and slowly releases it over several hours when placed in your mouth.

“Our goal is to develop an easy and affordable solution for dry mouth for the millions who suffer from this frustrating condition,” said Georgia Malandraki and Suman Debnath, two of the lead researchers on the project.

Though it may not seem glamorous, saliva is vital for a healthy mouth. It keeps your mouth moist, helps digest food, protects your teeth and gums, and even fights germs. When your body doesn’t make enough of it, your entire oral system struggles.

Natural saliva is mostly water, but it also contains special compounds called mucins. These sticky proteins give saliva its slippery feel. Mucins help coat your mouth and throat, making it easier to chew and swallow. They also form a protective barrier that shields your tissues from dryness and irritants.

On top of that, mucins play a role in your body’s defense system. They trap harmful bacteria and work alongside other germ-fighting agents like lysozyme and lactoferrin to keep your mouth clean and balanced. That’s why any good artificial saliva must contain mucins or similar ingredients to do the job right.

To design their artificial saliva system, the Purdue team turned to a gel-like material called a hydrogel. Hydrogels are soft, stretchy, and excellent at absorbing and releasing water-based fluids. They’re often used in contact lenses and wound dressings because of how gentle they are on the body.

The researchers mixed artificial saliva with a safe, flexible polymer known as poly(hydroxyethyl methacrylate), or PHEMA. This created a clear, soft gel the size of a U.S. quarter—small enough to sit comfortably inside your cheek or under your tongue.

They soaked the gel in artificial saliva for six hours and found it could absorb up to 400% of its original volume. That’s like a sponge swelling to four times its size. When warmed to body temperature (about 98.6°F or 37°C), the gel steadily released nearly all of its stored saliva over the next four hours. During the first hour, it gave off saliva at a rate of about 0.3 milliliters per minute—right in the range of natural salivary flow.

Not only did it work, but it worked repeatedly. The team tested the same gel five times in a row, and each time it released about 97% of its saliva content with the same timing and flow. That level of consistency points to a reusable solution, which is rare in current treatments for dry mouth.

Even more promising, when researchers placed human cells next to the gel in lab tests, the cells showed no damage or decline in health. That confirms the gel is biocompatible—safe to use inside the mouth without harming tissues.

Current dry mouth treatments tend to focus on either stimulating your own saliva production or replacing it artificially. But both paths come with tradeoffs.

Peptides and pharmaceutical sprays may help spark your glands to work harder. However, they usually wear off fast and can irritate your mouth. Some options require surgery or special devices, like electronic mouthpieces, which are invasive or expensive. Even “natural” treatments like mouthwashes or lubricants can dry up too soon or erode enamel if used often.

Denture-based solutions, such as saliva-holding trays or guards, are another choice—but they’re bulky, can leak, and often need adjusting throughout the day. For many, they’re uncomfortable and not discreet enough to use in public settings.

Artificial saliva made in labs has shown promise, especially when combined with mucins. It mimics many functions of natural saliva, including lubrication and microbial defense. But delivering it efficiently has always been a challenge—until now.

Hydrogels, which offer controlled release, may finally be the breakthrough researchers have hoped for. This saliva-gel acts more like a reservoir than a quick fix. It absorbs and slowly dispenses artificial saliva over time, helping restore comfort and function to the mouth without frequent reapplication.

While this new gel is not yet on pharmacy shelves, it’s already proving itself in lab tests. The team plans to further refine the formula to improve durability and increase how much saliva it can hold. One of their goals is to develop a fully dissolvable version, which would leave no residue and could be safely swallowed once used up.

To make the product truly viable, it must also meet real-world needs: comfort, affordability, long-lasting performance, and ease of use. That means more testing will be needed to evaluate how the gel behaves in an actual mouth—not just in the lab. The human mouth is a complex place filled with heat, pressure, bacteria, and constant motion. A successful product must work under all those conditions.

The team is also studying the physical strength of the gel. Right now, its flexibility and softness are an advantage, but its mechanical properties are much weaker than those of real cheek tissue. That means it could break down or wear out faster than desired. Finding the right balance between softness and strength will be key.

Even with those challenges, the potential is exciting. A hydrogel-based saliva delivery system could change the way people manage dry mouth. It could give people more freedom to eat, speak, and smile without discomfort—and reduce their risk of painful oral infections.

The project reflects a growing interest in noninvasive, wearable treatments that support everyday life. With the right tweaks and trials, this small gel could become a big deal for millions living with xerostomia.

Note: The article above provided above by The Brighter Side of News.

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