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Why is My Night Guard Turning Yellow?

10 min read
by JS Dental Lab |

A night guard (or mouth guard) is a type of oral appliance worn while you sleep.

And there are several reasons a dentist may recommend a night guard, like preventing jaw joint (TMJ) issues and minimizing the damage from bruxism (teeth grinding). 

Whatever the case, you may have noticed discoloration or yellow stains on your night guard and wondered: what does it mean?

If your night guard is turning yellow, it’s essential to identify the reason and your options are for addressing the issue. And we’re here to guide you through that!

We’ve got the answers to some of the most common questions about night guard discoloration, so let’s get started. 

Why is My Night Guard Turning Yellow?

Understandably, you’re concerned when you notice a change in a dental appliance, such as a night guard or mouth guard. Especially if it’s turning yellow! 

There is no one exact cause of night guard discoloration, but we’ll discuss a few of the reasons it might occur in this section. 

Bacteria Buildup

It’s gross but true: the same bacteria that lead to plaque, tooth decay (cavities), and bad breath can discolor your night guard, too. 

Overnight wear exposes your night guard to any food particles you might have missed during your nightly oral health care routine. Plus, no matter your pre-bed dental routine, bacteria buildup in your mouth over time.

And if you eat or drink anything other than water after you brush and floss and don’t repeat these steps before inserting your night guard, the risk of discoloration increases.

Other factors that impact bacteria buildup include improper storage, cleaning and drying techniques, and exposure to germs from children or pets. 

Bacteria build up comes with someone everyone dreads.....a smelly night guard. JS Dental offers a night guard cleaning spray to help with this. 

Night Guard Cleaner Spray


It’s Damaged

Your night guard will naturally develop bite marks, grinds, and scuffs over time if you are a tooth grinder or clencher. Damage like this is why we recommend that you replace your night guard every one to two years.

Why are visible signs of damage like scuff marks such a big deal? Bacteria can easily proliferate within the scratches, which, besides being dangerous to your oral health, can make your device yellow quicker.

But how and when did your night guard become damaged? 

Let’s consider a few possibilities of how you may have damaged your night guard in the first place:

  • Teeth grinding (bruxism)
  • Pressure from jaw clenching
  • Pets chewing on a dental device
  • Children using a dental device as a toy
  • Facial impact while wearing the device
  • Stepping on the device
  • Materials breaking down after cleaning with harsh chemicals
  • If your guard comprises hybrid materials and not high-quality thermo plastic, it will discolor quicker with time.

Related: HELP! My dog got my nightguard!

Improper Use

A night guard can be a total game-changer when it comes to meeting your oral health needs, relieving pain, or preventing your teeth from shifting. 

When you’ve experienced the benefits of a night guard, it might be tempting to start wearing it constantly. However, as the name implies, most night guards are only for use at night (or whenever you’re sleeping). 

By wearing it both day and night or as a sports mouth guard or whitening tray, you increase the likelihood of damage. The material will break down quicker. It also exposes your night guard (and your teeth) to more harmful bacteria. 

If you’re enjoying your night guard, there’s no need to overuse it, as the benefits may not outweigh the risks. Instead, speak with a dental professional about mouth guards and retainers intended for all-day wear and properly use them. 

It’s Just Old

Sometimes, the reason your night guard is turning yellow has nothing to do with how you’re using it, caring for it, or if it’s damaged. In many cases, oral appliances that become discolored are just old. 

Think about how long you’ve had your night guard, how frequently you use it, and why. 

There are several crucial reasons to discontinue using an old night guard and get a new one. Most importantly, an old night guards’ deteriorating materials negatively impact how your device fits. It won’t work as well (and can potentially cause harm to your dental health in some instances!). 

Fortunately, the solution is simple: have your night guard replaced. 

In the next section, we’ll cover how, when, and why to replace an old night guard, so keep reading if you suspect that’s what you’ll need to do!

What Should I Do if My Night Guard is Turning Yellow?

closeup of a young woman flossing her teeth

Regardless of the exact cause, once you notice yellow stains or other types of discoloration on your night guard, you’ll want to address the issue right away. 

The good news?

When your night guard is turning yellow, there are several simple options for solving the problem and preventing it in the future. All you need is some insight and know-how. 

These are the solutions most dental professionals recommend.

Maintain Your Oral Health Routine

Earlier in this article, we discussed how bacteria buildup could be one of the most common reasons people experience discoloration of an oral appliance. 

Sure, it can seem tedious to go through all the motions, particularly when you feel tired after a long day. But the benefits of proper dental hygiene extend far beyond maintaining the color of your night guard (we’ll provide more tips shortly). 

Clean Your Night Guard Properly

Cleaning your night guard is crucial to ensuring your mouth guard remains effective and doesn’t lead to unintended, harmful consequences. 

Proper cleaning includes both daily cleanings and less frequent deep cleanings. But be aware: how you do it matters, and the products you use matter even more (don’t worry, we’ll get to those details soon). 

Storage is Key

One of the most overlooked aspects of healthy mouth guard care (including night guards) is storage practices. 

Many people don’t overthink where or how they store their night guard while they aren’t wearing it. Still, without proper storage, any oral appliance can become the ideal breeding ground for harmful bacteria!

If stored without proper ventilation or a clean drying surface, the type of bacteria that can grow on your night guard can cause the yellow stains you see in the material, potentially causing more serious oral health conditions over time. 

Again, we’ll discuss the best practices for storing an orthodontic appliance later in this article. 

Replace Your Night Guard

It’s most likely not the answer you want to hear, but sometimes, the only way to address night guard discoloration is to replace your device when it’s time. 

The upside?

It’s never too late to implement better habits to prevent your dental devices from turning yellow in the future. 

Upgrade Your Device

If you’ve been using an over-the-counter night guard or stock sports mouth guard, the yellow stains are likely due to poor quality materials that deteriorate more quickly. 

Quick deterioration makes low-quality plastic and rubber more vulnerable to bacteria and, therefore, discoloration. 

Custom dental appliances comprise longer-lasting materials, and professionals craft them to fit your unique bite. 

Ultimately, the savings at checkout may not be worth the cost of replacing an over-the-counter mouth guard product more frequently than a more durable, comfortable, and practical custom night guard.  

Our 5 Dental Night Guard Side Effects [+ Solutions] blog can also help you!

 How Can I Improve My Oral Health Habits to Keep My Mouth Guard From Turning Yellow?

Caring for your teeth with the daily habits recommended by the American Dental Association (ADA) in their Home Oral Care Guide is essential for maintaining your night guard. 

Here’s what they recommend. 

Brush Your Teeth Twice a Day

Teeth brushing is the most important way to protect your teeth from the bacteria that cause plaque (tartar) buildup, tooth decay, and gum disease (periodontitis).

But did you know it’s also crucial for preventing yellow stains from appearing on your night guard?

It’s true, but brushing incorrectly can potentially cause more harm than good. 

Check out these basic tips to be sure you’re getting optimal results:

  • Brush and floss your teeth at least twice daily. 
  • Use fluoridated toothpaste.
  • Only use a soft-bristled toothbrush.
  • Add an alcohol-free mouthwash to kill bacteria and prevent gum disease.

Set Boundaries With Certain Foods and Beverages

Unfortunately, some of your best-loved foods and drinks may damage your teeth (and your night guard as a result). 

The solution?

Try limiting foods and beverages that are acidic, such as:

  • Coffee and tea
  • Alcohol
  • Fermented foods
  • Tomatoes and tomato-based sauces 

Avoid consuming too much sugar and starch, which encourages bacterial growth. 

Check out some of the most common culprits:

  • Soft drinks (soda and pop)
  • Juice
  • Refined carbohydrates (white bread, rice, potatoes, and pasta)

Pro Tip: limiting foods and beverages high in sugar, starch, and acid goes a long way in maintaining your overall dental health. And again, be sure not to consume anything at all after your oral care routine except for water before inserting your night guard and falling asleep. 

Snack attack? No problem. Repeat the steps of flossing, brushing, and rinsing with mouthwash if it happens. 

How Do I Care For My Appliance to Keep It From Turning Yellow?

closeup of a young woman and her night guard

The best way to prevent your night guard from turning yellow is to care for it properly. Sure, it’s a bit extra work, but it’s worth the effort to preserve the integrity of any dental appliance and ensure long-lasting quality wear. 

Prevent mouth guard discoloration with these steps: 

1. Start with a Quality Product

Never underestimate the value of opting for a high-quality, custom night guard. 

At JS Dental Lab, this is our wheelhouse! Technicians make these just for you using materials that withstand the test of time and wear. 

Over-the-counter products have a lower initial price tag, but you really do get what you pay for when it comes to night guards!

2. Clean Your Night Guard Daily

Even if you’re diligent about your oral health care routine, your night guard may not be as clean as you think if you aren’t cleaning it daily. 

Germs and bacteria build up on any dental appliance over time — in this case, overnight. 

The good news?

You can clean your night guard daily using a soft-bristled toothbrush and toothpaste, dish soap, antibacterial hand soap, or a paste made from baking soda and water. 

After gently scrubbing the inside and outside of your night guard, rinse it completely clean using cool water or lukewarm water (hot water can damage or warp the material). 

Then, allow the night guard to fully air dry in a well-ventilated location on a clean surface that’s safe from children and pets. 

Pro tip: be confident that whichever cleaner you use to wash your mouth guard each day is free from alcohol or harsh chemicals, which can break down the materials more quickly. 

You can also opt for a gentle yet effective night guard cleaner that does the work for you.

3. Deep Clean Your Night Guard Once Per Week

A few minutes of cleaning your night guard each morning after removing it goes a long way in preventing yellow stains and discoloration. 

But when it comes to eliminating the majority of harmful bacteria on the surface of any oral appliance (including retainers, sports mouth guards, and night guards), weekly deep cleaning is essential. 

Don’t worry: deep cleaning a night guard is just as simple as the recommended daily cleaning process. 

There are a few options, including:

  • Soak your night guard in hydrogen peroxide diluted with water for 10-15 minutes, then rinse with room temperature water (never hot water)
  • Use a combination of ultrasonic cleaner + solution such as HP diluted with water, retainer or cleaner aligner cleaning tablets, or dentaSoak (we sell these).
  • Bring your night guard to a dentistry clinic for a hygienist or dentist to clean professionally 

Important note: never use household cleaners, antibacterial wipes, hand sanitizer, or bleach to clean your night guard. These products contain harsh chemicals that can damage your mouth guard or cause serious harm to your health when misused. 

Always double-check the correct cleansing procedure with your appliance’s manufacturer.

4. Store Your Night Guard Properly

Last but certainly not least: storing your night guard properly is not optional if you want to keep it clean, make it last longer, and avoid the bacteria buildup that leads to the device turning yellow. 

Follow these simple rules for best results: 

  • After each daily or deep clean, place your night guard on a clean surface where it can safely air dry 
  • Only store and travel with your device in a well-ventilated mouth guard case 
  • Keep your night guard out of reach from children and pets who may transfer germs through touching or chewing the device 

Don't forget to also check out Our Best Tips for Sleeping With a Mouth Guard!

How Do I Remove Yellow Stains From My Night Guard?

Once your night guard or mouth guard has already started turning yellow, there’s no guarantee you can remove these stains or discolorations.

While many websites claim to offer at-home tricks and remedies, be aware that these techniques may not be the right solution for your issue. And in fact, they may cause irreversible damage to your night guard!

Contact the manufacturer or bring the device to an orthodontic practice for assessment to determine how to remove yellow stains from your night guard. 

Sometimes, they can provide professional advice on how to address the problem and prevent future discoloration. They may recommend a replacement. 


When you’ve made a personal investment in your overall well-being by purchasing a night guard, it goes without saying that you want it to last. 

It may cause significant concern when you start to notice yellowing or stains on your night guard. But there are simple ways to address the issue and avoid the problem in the future!

We’re always here to answer your questions, whether you’ve ordered a quality custom night guard from us or not. Please reach out to JS Dental Lab with your concerns anytime!

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