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Why does it stink when I floss my teeth?

If you’ve ever flossed your teeth and been hit with an unpleasant odor, you’re not alone. That foul stench when flossing is actually quite common. But what causes it? And what can you do to prevent it? Keep reading to find out.

What Causes the Flossing Odor?

When you don’t floss regularly, food particles, bacteria, and dead cells can build up between your teeth. This debris creates a layer of plaque on your teeth. As plaque accumulates, it hardens into tartar. Both plaque and tartar provide an ideal environment for bacteria to thrive.

These bacteria feed on the food particles and dead cells stuck in your teeth. As they digest this debris, the bacteria release sulfur compounds. These sulfur compounds are what produce the rotten egg-like smell when you floss.

So in essence, the stinky flossing odor is caused by the gunk trapped between your teeth that bacteria feed on and digest.

Main Causes of Plaque and Tartar Buildup

There are a few key reasons plaque and tartar tend to accumulate between teeth:

  • Not flossing regularly – Flossing helps disrupt plaque before it hardens into tartar.
  • Improper flossing technique – If you don’t use the proper method, you may miss areas where plaque accumulates.
  • Consuming sugary foods/drinks – Sugars feed the plaque-causing bacteria.
  • Poor oral hygiene – Not brushing and flossing properly allows more plaque to build up.
  • Dry mouth – Insufficient saliva can’t wash away plaque bacteria.
  • Gum disease – Bleeding gums provide bacteria more food to thrive.
  • Irregular teeth – Crooked or crowded teeth are harder to clean.
  • Smoking – Chemicals in smoke irritate gums and promote plaque growth.

Places Where Plaque and Tartar Hide

Plaque and tartar tend to accumulate in certain spots around your teeth where they can avoid disruption. Areas where you may notice more buildup and flossing odors include:

  • Between back molars
  • Around dental fillings and crowns
  • At the gum line
  • In tooth grooves and pits
  • Between teeth that are tightly spaced
  • Around and under the gumline
  • Near wisdom teeth

Pay extra attention when flossing around these areas to remove plaque before it hardens into smelly tartar.

Bacteria That Cause the Flossing Odor

There are over 700 species of bacteria that can live in the oral microbiome. The main types of bacteria responsible for the unpleasant flossing odor include:

  • Porphyromonas gingivalis – Associated with gum disease.
  • Prevotella intermedia – Produces hydrogen sulfide gases.
  • Fusobacterium nucleatum – Binds plaque bacteria together.
  • Actinomyces viscosus – Forms plaque on smooth surfaces.
  • Streptococcus mutans – Metabolizes sucrose into lactic acid.

As these and other bacteria feed on debris stuck between teeth, they generate smelly metabolic waste products. Removing plaque and tartar via flossing helps disrupt these odor-causing bacteria.

Other Oral Health Conditions That Cause Bad Breath

While poor flossing habits are the most common culprit behind foul flossing odors, other oral health issues can also contribute to bad breath. These include:

  • Gum disease – Inflamed gums bleed, giving bacteria more to feed on.
  • Cavities – Food and bacteria decay teeth and emit odors.
  • Dirty or failing dental work – Bacteria accumulate on old fillings, crowns, and dentures.
  • Mouth sores – Ulcers or cuts allow bacteria to enter tissue.
  • Dry mouth – Reduced saliva flow can’t wash away odor-causing bacteria.
  • Food impaction – Trapped food rots and smells.
  • Tobacco use – Smoking introduces foul odors.

Tell your dentist if you notice persistent bad breath even after improving your flossing routine. It could indicate an underlying dental health issue needs treatment.

How to Prevent Smelly Flossing Odors

Here are some tips to help prevent foul odors when you floss:

  • Floss thoroughly once a day – Make it part of your nightly oral hygiene routine.
  • Use proper flossing technique – Carefully insert floss between each tooth and rub side-to-side.
  • Rinse your mouth – Swish water around after flossing to wash away dislodged bacteria.
  • Brush twice daily – Brushing removes plaque before it hardens into tartar.
  • Clean your tongue – Bacteria and food debris on your tongue contribute to odor.
  • Limit sugary foods/drinks – Sugars feed the odor-causing oral bacteria.
  • Drink water – Staying hydrated promotes saliva flow to cleanse your mouth.
  • Avoid tobacco – Smoking introduces foul smells and dries out your mouth.
  • Get regular dental cleanings – A hygienist can remove hardened tartar.

Practicing good oral hygiene habits like flossing, brushing, and hydration will help disrupt plaque and tartar. This removes smelly bacteria and debris from your mouth and gums.

When to See a Dentist About Flossing Odors

You should make an appointment with your dentist if you notice:

  • Persistent bad breath or flossing odors
  • Red, swollen, or bleeding gums
  • Receding gum lines
  • New areas of plaque or tartar buildup
  • Increased tooth sensitivity
  • Loose teeth

These signs may indicate gum disease or tooth decay. The dentist can assess your oral health, clean your teeth professionally, and provide tips to improve your flossing technique.

Professional Cleanings to Remove Plaque and Tartar

While daily flossing helps, some plaque and tartar will still accumulate over time. To thoroughly remove built-up tartar, periodic professional cleanings are recommended. Your dentist may recommend having your teeth scaled and polished every:

  • 3-6 months if you have gum disease
  • 6-12 months if you have a moderate amount of tartar
  • 12-24 months if you have minimal tartar

More frequent dental cleanings can help disrupt odor-causing plaque and bacteria. Proper flossing technique is still important between professional cleanings.

Flossing Best Practices

To get the most plaque-removal and odor-fighting benefits from flossing, be sure to:

  • Use 12-18 inches of floss
  • Gently insert floss between teeth
  • Avoid snapping floss down into gums
  • Rub side-to-side to dislodge plaque
  • Curve floss into a C-shape around molars
  • Floss behind your back teeth
  • Use a clean section of floss for each tooth

With proper technique and consistency, flossing can help prevent smelly plaque and tartar from building up.

Flossing Alternatives

If you have trouble flossing with traditional floss, consider using flossers or interdental cleaners:

  • Flossers – Disposable Y-shaped tools that combine floss with a pick.
  • Interdental brushes – Small bristled picks for cleaning between wider teeth.
  • Water flossers – Powered water jets to flush out debris.
  • Wooden plaque removers – Wood picks help clean around dental work.
  • Oral irrigators – Devices that use water pressure to clean teeth.

Talk to your dentist about which flossing alternatives may work best for your teeth.

Keep Your Mouth Clean and Freshened

Practicing good oral hygiene is key to preventing foul flossing odors. Here are some extra tips for keeping your mouth clean and freshened:

  • Use antibacterial mouthwash – Helps kill odor-causing bacteria.
  • Chew sugarless gum – Increases saliva flow to cleanse your mouth.
  • Drink green tea – Shown to inhibit oral bacteria growth.
  • Eat crunchy fruits/veggies – Helps rub plaque off teeth.
  • Drink plenty of water – Flushes out food debris and bacteria.
  • Suck on mint leaves – Mint naturally freshens breath.
  • Scrape your tongue – Cleans bacteria/debris off the tongue.

Along with diligent flossing, these tips can leave your mouth cleaner and keep bad odors at bay.

When to Seek Medical Advice

In some cases, persistent halitosis (bad breath) may be a sign of an underlying health condition. You should contact your doctor if you notice bad breath along with:

  • Changes in breath odor
  • Unexplained weight loss
  • Difficulty swallowing or speaking
  • Chronic dry mouth or thick saliva
  • Frequent nausea or vomiting
  • Coughing up blood

These symptoms could indicate health issues like respiratory infections, diabetes, liver or kidney disease. Proper treatment of the condition may help improve bad breath.

When to Change Your Flossing Routine

As dental health changes over time, you may need to adjust your flossing technique. Consult your dentist about flossing more often if you:

  • Have braces or dental appliances fitted
  • Have signs of gum recession
  • Are undergoing cancer treatment
  • Have had periodontal surgery
  • Are recovering from oral surgery
  • Have gum disease or frequent bleeding

Your dentist can demonstrate proper flossing methods for your individual oral health needs.


Smelly flossing odors are commonly caused by plaque and tartar buildup that provides food for odor-producing oral bacteria. Practicing good flossing technique daily, getting regular dental cleanings, and maintaining proper oral hygiene can help diminish foul flossing odors. Pay attention for any signs of persistent bad breath that could indicate other dental health or medical issues. With proper prevention and treatment, you can keep your mouth fresh and avoid foul flossing stenches.

Key Facts and Statistics

Fact Statistic
Adults who never floss 40%
Adults who floss daily 30%
Plaque can reform after 24 hours Up to 50%
Bacteria in the mouth 700+ species
Saliva pH to prevent cavities Above 5.5
Gum disease prevalence 50% of adults 30+
Bad breath prevalence 50% population
Dental caries worldwide 2.4 billion people
Flossing can reduce gingivitis Up to 50%

Proper flossing technique and oral hygiene habits are important for disrupting plaque, controlling bacteria, and preventing bad breath and dental issues. Consistent flossing can help reduce gingivitis, gum disease, cavities, and foul odors.