Tooth decay (also called cavities or dental caries) is a very common dental health problem in the United States. According to the CDC, more than 20 percent of children under age 12 have tooth decay in their permanent teeth. This number rises to about 60 percent for teens. Those who make it to adulthood cavity-free aren’t out of the woods since cavities can and do strike people of all ages. Tooth decay can cause a number of problems including:
- Weakening the tooth structure, making teeth prone to fracture
- Giving bacteria access to tooth pulp, leading to dental abscesses (infection requiring a root canal)
- Making teeth look unattractive with discoloration, pitting or holes
- Increasing the lifetime cost of dental care with fillings, crowns and other restorations
- Contributing to the loss of permanent teeth
How Does Tooth Decay Happen?
Dental decay is caused by an interaction between bacteria and the outer layers of the tooth (enamel and dentin). Everyone has some oral bacteria in their mouth. Certain strains such as Streptococcus mutans are particularly likely to cause cavities. These microbes feed on residue left behind after you eat or drink anything containing sugar or starch (simple carbohydrates). As the bacteria feed, they secrete waste products that are highly acidic. Bacteria and bacterial waste along with food residue and components of your saliva can all combine to form a slimy biofilm called plaque. Plaque is very sticky and adheres to the surface of your teeth.
The acids produced by the bacteria in plaque can gradually dissolve hard enamel. When this happens, tiny holes form in the mineral-rich enamel. Saliva normally deposits calcium and other minerals into tooth enamel through a process called remineralization. That’s what keeps teeth strong over the years. However, continued exposure to an acidic environment eats away enamel faster than saliva can restore it. Over time, the tiny pits and holes can become wider and deeper, developing into full-blown cavities. These can reach beyond the enamel layer into the softer dentin underneath. They can also extend below the gum line and attack the cementum that covers the tooth root. If left untreated, a cavity may penetrate all the way into the pulp of a tooth, killing the nerve and eventually destroying the tooth completely.
Causes of Tooth Decay
Some people are more susceptible to dental caries than others. Medical researchers are still trying to determine how much of this susceptibility is genetic. Although it’s possible that having naturally thin enamel may play a role, there are many other factors including bacterial resistance and the chemical makeup of saliva that are also important. There are certainly a number of unfortunate patients who take excellent care of their teeth and still end up with cavities. However, environmental factors and lack of proper oral care play a bigger role than genetics for most people. Here are some of the most common factors that increase the risk of tooth decay:
- Poor dental hygiene (usually failure to brush and floss correctly and frequently)
- Regular snacking on sugar and starch-filled snacks and drinks (this provides bacteria with a constant food supply)
- Drinking acidic beverages too frequently (this includes sodas, juices, coffee, wine, etc.)
- Skipping dental appointments (this allows cavities to expand unchecked)
- Lack of access to preventive dental care such as dental sealants (children from lower-income families are less likely to have sealed molars and more likely to have cavities)
- Living in an area without water fluoridation (daily exposure to a small amount of fluoride can help keep bacteria under control)
- Chronic dry mouth (having sufficient saliva is critical because it attacks bacteria, neutralizes acids and helps remineralize enamel)
- Failing to prevent or treat gum disease (receding gums leave the vulnerable layer of cementum exposed to bacterial attack)
- Ignoring a fracture or other tooth damage that allows bacteria to penetrate into the tooth more easily
What You Can Do About Tooth Decay
When you understand how cavities form, it’s easier to see how your daily habits can increase or decrease your risk. There’s currently no way to completely eradicate oral bacteria. But you can reduce how much plaque is in your mouth and limit acid contact with your enamel. Learn and use appropriate brushing and flossing techniques. Brush at least twice daily with a fluoride toothpaste and floss at least once a day. Rinse your mouth well with water after any sugary treat if you don’t have a toothbrush with you. See your dentist regularly and don’t ignore symptoms like dry mouth that can signal trouble for your teeth.
If you do end up with tooth decay, get the cavity filled as soon as possible. The techniques and materials used to restore your tooth can actually help prevent further decay. Getting a small cavity filled is much more comfortable and less expensive than getting a full crown – or replacing a tooth entirely. Today, there are many tooth-colored restoration options that can make your teeth look like new again. These include dental composite, ionomers and ceramics.