Cavity Between Teeth: Causes, Treatments, and Prevention

Posted on June 4, 2021

One of the most common places to get a cavity is between the teeth. Technically called an interproximal cavity, these types of dental cavities (also called caries or tooth decay) often happen in tight spaces that are difficult to brush or floss.

Cavities happen when the hard outer layer of the teeth, the tooth enamel, starts to break down. The enamel is made of minerals like calcium and phosphate. As teeth lose these minerals in a process called demineralization, enamel gets weaker and more prone to cavities.

It’s easy to prevent interproximal cavities, luckily. It’s also relatively simple to treat cavities between your teeth if you catch them early enough. Regular dental checkups are essential so that your dentist can spot these cavities early in their development.

Signs Of A Cavity Between The Teeth

Cavities between the teeth can be difficult to see until they’re sizeable. That’s why they’re usually first found at a dental checkup. Your dentist takes bitewing x-rays to look for and identify interproximal cavities before they get too big.

If you’re concerned you’ve developed a cavity (interproximal or otherwise) since your last dental visit, here are the most common symptoms:

  • Tooth sensitivity
  • Toothache or pain in your teeth, especially if it shows up suddenly
  • Pain when you eat or drink cold, hot, or sweet foods or beverages
  • Pain while chewing
  • Brown, yellow, or black spots or stains on the teeth
  • Pits or holes on the surface of the teeth
  • Bad breath

Is a cavity between the teeth painful? A cavity between the teeth can be painful if it reaches through the enamel to the second layer of the tooth, called dentin. Sensations travel more easily through the dentin to the nerves in the teeth, causing pain.

Can cavities spread to other teeth? Yes, cavities can spread to other teeth. An interproximal cavity on one tooth can create a home for cavity-causing bacteria. They secrete acids between teeth, which over time cause a cavity in the adjacent tooth.

Why Do Cavities Form Between Teeth?

Cavities form when enamel starts to weaken due to poor oral hygiene. Regular brushing and flossing help remove the bacteria that cause cavities. These habits are crucial in breaking up colonies of plaque that attempt to attach to the teeth.

Proper dental care is one of the best ways to prevent cavities from forming between the teeth and elsewhere in the mouth.

Cavities form when bacteria in the mouth begin to proliferate after you eat sugary foods. As these bacteria multiply, they create plaque buildup, a biofilm that protects them and makes them harder to remove while brushing.

Without regular brushing and flossing, or when the oral microbiome is out of balance, bacteria can hide out between the teeth in crevices or places where they touch.

Over time, plaque hardens and turns into tartar, which is essentially impossible to remove with a toothbrush and dental floss. You’ll need to see your dentist to have it removed.

As they grow, the bacteria secrete acids that break down and demineralize tooth enamel. Eventually, a small pit or hole forms in the enamel. Bacteria stick to the pit, where they’re even harder to remove, secreting more acid and making the cavity worse.

If you have regular dental checkups, your dentist can usually catch interproximal cavities before they get too deep.

If you don’t treat the cavity early, the bacteria will eventually erode through the enamel and dentin and reach the pulp of the tooth, which will be painful and require more invasive treatment.

What causes cavities between teeth? Not flossing properly causes cavities between the teeth in most cases. People either don’t do a good job of flossing between their teeth or skip it altogether, allowing cavity-causing bacteria to build up in the crevices between the teeth.

In some cases, mineral deficiencies also allow the cavities between the teeth to develop more quickly.

What Do Cavities Between The Teeth Look Like?

Cavities between the teeth are difficult to spot unless they’ve gotten very large. If you see any discolored patches between your teeth that appear yellow, brown, or black, go see a dentist.

Early detection of interproximal cavities usually happens with bitewing x-rays at the dentist. When your dentist reviews your x-rays, they may see areas of enamel and dentin that look darker than the rest of the tooth. That’s a sign of a cavity, and they’ll recommend getting a filling.

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Interproximal Cavity Treatments & Costs

Can cavities between teeth be fixed? Yes, cavities between teeth can be fixed. The recommended treatment depends upon the size of the cavity and where it’s located.

You can heal a cavity yourself if it’s not too deep. If a cavity is forming in the outer half of the enamel, you can heal it by remineralizing the enamel there. Use hydroxyapatite toothpaste to remineralize and harden the enamel so that you won’t need a filling.

If the cavity goes through more than half of the enamel, or if it’s reached the dentin layer underneath, you’ll need a filling or more substantial work. Dental fillings are made of a composite resin — I strongly discourage amalgam — that bonds to teeth and replaces the decayed enamel.

Fillings aren’t the same thing as dental crowns. Fillings are used to treat smaller cavities, while dental crowns replace the entire surface of the tooth. They’re used when a cavity is so big that the remaining tooth can’t support a filling.

If the cavity isn’t treated in the early stages and the inner pulp becomes infected, you’ll need a root canal. After a root canal, your dentist will usually cover the tooth with a dental crown.

If the infection from a cavity is severe, the tooth may need to be extracted and replaced with a dental implant.

Here’s the cost by treatment:

  • Cavity: It usually costs between $150-$250 to get a cavity filled. Dental insurance will generally cover most or all of the cost after your deductible is met.
  • Dental crown: Crowns run between $800-$3,500 without insurance.
  • Root canal: A standard root canal can cost upwards of $1,800. You’ll likely also need to pay for a crown if a root canal is necessary.

How To Prevent A Cavity Between Teeth

Getting a cavity is no fun, but luckily you can avoid them altogether.

Here are the top ways to prevent cavities from forming between your or your child’s teeth:

  • Having good oral hygiene
  • Using hydroxyapatite toothpaste
  • Eating a healthy diet
  • Avoiding snacking
  • Eating more calcium
  • Eating more vitamin D3 and K2
  • Taking oral probiotics
  • Breathing through your nose
  • Oil pulling
  • Oil pulling
  • Dental sealants

Let’s break down each of these preventative measures.

Good Oral Hygiene

Proper dental hygiene, such as flossing every day and brushing at least twice a day, is the best way to prevent interproximal cavities. It’s crucial to floss carefully between the teeth and below the gum line to make sure you remove as much plaque as possible.

Use Hydroxyapatite Toothpaste

Brush with a hydroxyapatite toothpaste instead of fluoride toothpaste. You’ll help restore your enamel without all of the nasty side effects of fluoride.

Traditional dentistry recommends a fluoride gel to remineralize teeth, but fluoride can cause many concerning side effects. Instead, I recommend using hydroxyapatite to remineralize teeth. Hydroxyapatite works just as well as fluoride, but it’s safer to use.

Make sure to brush all of the flat surfaces and chewing surfaces of the teeth. You should always brush your teeth before bed to avoid overnight plaque buildup.

Eat a Healthy Diet

Eating a healthy and well-balanced diet full of fruits, vegetables, and other whole foods is one of the best things you can do to support your oral health. You’ll give the body the nutrients it needs to support healthy teeth.

Skip Snacking

Avoid snacking, which gives cavity-causing bacteria more fuel to grow and spread. If you can’t resist, be sure to brush your teeth after you’re done.

Be particularly mindful not to snack on foods with refined sugars or refined flour, like crackers. Crackers are terrible for kids’ teeth!

Get The Right Nutrients

Eat more vitamins K2 and D3, or take a supplement that contains these vitamins. These vitamins work in conjunction to help your body absorb calcium from the foods you eat, preventing tooth decay and demineralization.

In conjunction with vitamins K2 and D3, make sure you’re getting enough calcium, which your body uses to strengthen and remineralize enamel. Calcium-rich foods include leafy green vegetables, legumes, tofu, seafood, and dairy products.

Oral Probiotics

Chewing an oral probiotic supports the healthy flora in your mouth. Unlike a typical probiotic that you swallow, an oral probiotic works right where the cavity-causing bacteria live. Probiotics help buffer enamel-harming acids and actively fight against pathogenic bacteria.

Breathe Through Your Nose

Mouth breathing negatively impacts teeth. When you breathe through your mouth instead of your nose, it dries the saliva in your mouth. Saliva helps kill the bacteria that create cavities, and without it, you’re much more likely to have cavities and other oral health problems.

Oil Pulling

Oil pulling is a great way to prevent cavities naturally, including cavities between your teeth. Oil pulling helps reduce plaque and gingivitis and fights cavity-causing bacteria in both kids and adults. Pulling oil can also reach between teeth, complementing a flossing habit.

Oil pulling is simply swishing organic oil (my favorite is virgin coconut oil) in your mouth for several minutes before spitting it out. I recommend starting out by swishing for a minute or two, then gradually working your way up to swishing for 20 minutes.

Dental Sealants

If you or your child have thin enamel due to enamel hypoplasia or another condition, dental sealants could be a good option. They provide a protective barrier over the enamel so bacteria can’t cause tooth decay.

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Why Are Interproximal Cavities So Common?

Interproximal cavities are so common because most people don’t floss properly or frequently enough. Many people skip flossing because they think they don’t have the time.

It’s better to spend a few minutes flossing today than a few hours in the dentist’s chair later. Flossing is perhaps the most important thing you can do to improve your oral health overall.

Careful flossing can reduce kids’ risk of getting cavities between the teeth by 40%. Unfortunately, many children and teens feel unmotivated to floss, which is why so many get cavities. I like to read to my children or have a dance party as we floss to make flossing fun.

The average person only removes 60% of the plaque between teeth when they floss. It’s a good idea to spend a little extra time flossing to make sure you’re removing everything you can. Supervise your kids’ flossing as much as possible to make sure they’re effectively flossing.

Cavity Between Teeth: The Final Word

Cavities between teeth are extremely common, but they’re also highly preventable. If you and your kids have good oral hygiene and eat a healthy diet full of essential nutrients, you’ll be well on your way to preventing interproximal cavities.


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