How Cavities Develop and How They Are Treated?

Cavities develop when bacteria in your mouth feed on sugars and starches from food, producing acids that wear down tooth enamel and create holes in your teeth. Treatment depends on how far the decay has progressed, ranging from fluoride therapy for early-stage damage to fillings, crowns, or root canal treatment for advanced cases. According to the World Health Organization, untreated dental caries in permanent teeth affects roughly 2.5 billion people worldwide, making it the most common chronic health condition on the planet. This article explains what causes cavities to form, the stages of tooth decay, how we treat cavities at every stage, and what you can do to prevent them.

How Cavities Develop in Your Teeth

Cavities form through a process called demineralization. Your mouth is home to hundreds of types of bacteria. Some of these bacteria are helpful, but others are harmful. The harmful bacteria combine with food particles and saliva to form a sticky film called plaque. Plaque begins building up on your teeth within 20 minutes of eating, according to the National Library of Medicine.

When you eat or drink anything containing sugar or starch, the bacteria in plaque use those sugars to produce acids. These acids attack the hard outer layer of your teeth, called enamel. Over time, repeated acid attacks cause the enamel to lose minerals like calcium and phosphate. This is how a cavity starts.

If plaque is not removed through brushing and flossing, it hardens into a substance called tartar (also known as calculus). Tartar is much harder to remove and can only be cleaned off during a professional dental cleaning. Plaque and tartar buildup also irritates the gums and can lead to gingivitis and periodontal disease, which creates even more problems for your teeth and overall health.

According to the CDC, more than 80% of Americans have had at least one cavity by the time they reach their mid-30s. That number shows just how common this condition is, even among people who brush regularly. Patients in Bethesda and the surrounding areas who keep up with regular checkups and cleanings are far more likely to catch early signs of decay before a cavity forms.

The Stages of Tooth Decay

Tooth decay does not happen overnight. It moves through several stages, and catching it early makes treatment simpler and less invasive.

Stage 1: Demineralization. White spots appear on the enamel surface. At this point, no hole has formed yet. The enamel is losing minerals but can still be repaired with fluoride treatment. This is the only stage where decay can be reversed without a filling.

Stage 2: Enamel decay. The enamel breaks down further and a small hole forms. You may not feel any pain at this stage because enamel has no nerve endings. This is one reason why regular dental exams in Bethesda are so important. We use advanced technology like DIAGNOdent, a handheld laser instrument, to detect early cavities that may not be visible to the naked eye.

Stage 3: Dentin decay. Once decay moves past the enamel and reaches the dentin (the softer layer beneath), it spreads faster. According to a study published in the journal Caries Research, decay on root surfaces progresses 2.5 times faster than decay through enamel. At this stage, you may start feeling sensitivity to hot, cold, or sweet foods. A dental filling is typically the treatment at this point.

Stage 4: Pulp involvement. If decay reaches the innermost part of the tooth (the pulp), it can cause severe pain, swelling, and infection. The pulp contains nerves and blood vessels. At this point, a root canal treatment is usually needed to save the tooth.

Stage 5: Abscess. An untreated cavity can lead to a tooth abscess, which is a pocket of pus caused by bacterial infection. According to the Cleveland Clinic, an abscess can cause facial swelling, fever, and pain that radiates to the jaw and ear. Left untreated, the infection can spread to other parts of the body and become life-threatening.

What Causes Cavities to Form

Several factors increase your risk of developing cavities. Knowing these risk factors helps you take steps to prevent decay before it starts.

Frequent snacking is a major contributor. Every time you eat, your teeth are exposed to acid for about 30 minutes. Constant snacking keeps acid levels high throughout the day, giving enamel less time to recover.

Sugary and starchy foods are especially harmful. Sticky foods like dried fruit and candy cling to teeth longer and give bacteria more fuel to produce acid. Acidic drinks like soda, coffee, wine, and sports drinks lower the pH in your mouth and weaken enamel directly, whether or not they contain sugar.

Dry mouth is another risk factor. Saliva plays a critical role in washing away food particles and neutralizing acids. Conditions like Sjogren’s syndrome, as well as medications like antihistamines and antidepressants, can reduce saliva flow and increase cavity risk.

Patients throughout Bethesda, Chevy Chase, Potomac, and Rockville who are taking medications that cause dry mouth should let us know during their appointments so we can recommend ways to protect their teeth.

According to the CDC’s 2024 Oral Health Surveillance Report, adults in higher poverty groups are nearly twice as likely to have untreated cavities (39.6%) compared to adults in lower poverty groups. Limited access to dental care drives much of this gap.

How Cavities Are Diagnosed

Cavities are diagnosed through a combination of visual examination, dental instruments, and imaging. During your exam, Dr. Hornstein will visually inspect each tooth and use a dental probe to check for soft spots on the enamel surface. A tooth with a cavity will feel different to the probe than a healthy tooth.

We also rely on advanced dental technology for accurate diagnoses. Digital X-rays reveal decay between teeth and below the surface that may not be visible during a visual exam. Our DIAGNOdent laser can detect the earliest stages of enamel breakdown, often before a cavity is visible or causes any symptoms.

Most cavities are found during routine dental checkups, which is why the American Dental Association recommends visiting your dentist every six months. Many patients in Silver Spring and North Bethesda come to our office for these twice-yearly visits, and that consistent schedule is the best way to catch decay early.

How Cavities Are Treated at Each Stage

Treatment for cavities depends on the severity of the decay.

Fluoride treatment. For very early cavities where the enamel has been weakened but not yet broken through, professional fluoride application can help the tooth remineralize and repair itself. The National Institute of Dental and Craniofacial Research confirms that fluoride can prevent tooth decay from progressing and even reverse early decay. This is the least invasive option and one more reason to keep up with regular visits.

Dental fillings. When a cavity has formed a hole in the tooth, a filling is the standard treatment. We remove the decayed material and fill the space with a tooth-colored composite resin. Composite resin matches the natural appearance of your tooth and is strong enough for use anywhere in the mouth, including back teeth where most chewing happens.

Our office also uses laser dentistry for certain cavity preparations, which can reduce the need for injections and make the experience more comfortable for patients of all ages.

Crowns, inlays, and onlays. If decay is more extensive and a large portion of the tooth structure is damaged, a filling alone may not provide enough support. In these cases, a crown, inlay, or onlay restores the tooth’s strength and shape. A crown covers the entire visible portion of the tooth, while inlays and onlays are custom-fitted restorations that repair specific areas of damage.

Root canal treatment. When decay has reached the pulp of the tooth, root canal therapy is necessary. We remove the infected nerve tissue, clean the inside of the tooth, and seal it with a filling material. A crown is often placed afterward to protect the tooth. Modern root canals are comfortable procedures, and our Bethesda office offers nitrous sedation for patients who feel anxious about dental treatment.

Extraction and tooth replacement. In the most severe cases, a tooth may be too damaged to save. If extraction is needed, we offer replacement options to restore your bite and appearance.

For patients who need a single tooth replaced, dental implant restorations provide a permanent, natural-looking solution that functions just like a real tooth.

Cavity Treatment Options Compared

Treatment	When It Is Used	What It Involves	Typical Longevity
Fluoride Treatment	Early enamel demineralization (no hole yet)	Professional fluoride gel or varnish applied to teeth	Reapplied every 3 to 6 months
Composite Filling	Small to moderate cavities in enamel or dentin	Decayed material removed, tooth filled with composite resin	5 to 15 years (ADA)
Crown, Inlay, or Onlay	Extensive decay with significant tooth structure loss	Custom restoration fitted over or into the damaged tooth	10 to 30 years (ADA)
Root Canal	Decay reaching the pulp, causing infection or pain	Infected pulp removed, tooth sealed, crown placed	10 to 15+ years with crown (AAE)
Extraction + Implant or Bridge	Tooth too damaged to save	Tooth removed, replaced with implant restoration or bridge	15 to 25+ years (ADA)

Sources: American Dental Association (ADA), American Association of Endodontists (AAE), National Institute of Dental and Craniofacial Research (NIDCR)

How to Prevent Cavities

Preventing cavities comes down to a few consistent habits. Brush your teeth at least twice a day with fluoride toothpaste. Floss at least once a day to remove plaque and food particles from between teeth where your toothbrush cannot reach.

Limit sugary and acidic foods and drinks. When you do have them, rinse your mouth with water afterward. Avoid snacking throughout the day, since each time you eat, your teeth face another round of acid exposure.

According to the ADA, community water fluoridation reduces tooth decay by at least 25% in children and adults. The CDC has named water fluoridation one of the 10 great public health achievements of the 20th century.

Dental sealants are another effective prevention tool. According to the CDC, sealants reduce the risk of cavities in permanent molars by 80% for two years after placement and continue to protect against 50% of cavities for up to four years. Children aged 6 to 11 without sealants are almost three times more likely to develop cavities than children with sealants. We offer sealants as part of our children’s dentistry services in Bethesda.

Professional cleanings every six months remove tartar buildup that regular brushing cannot address. Families in Potomac, Silver Spring, and throughout Montgomery County who maintain a consistent cleaning schedule give their teeth the best possible protection against decay.

Frequently Asked Questions

What Is the Biggest Cause of Cavities?

The biggest cause of cavities is the combination of bacteria, sugar, and acid in your mouth. When plaque bacteria break down sugars from food and drinks, they produce acids that erode tooth enamel. According to the WHO, the consumption of free sugars is the most significant risk factor for dental caries. Frequent snacking, poor brushing habits, and a diet high in sugar and starch all accelerate this process.

Are Cavities Normal at 25?

Yes, cavities are normal at 25. According to the CDC, more than half of adolescents aged 12 to 19 have already had a cavity in their permanent teeth, and about 90% of adults over 20 have experienced at least one cavity. People in their 20s are especially prone to smooth-surface decay that forms between teeth. Regular checkups in Bethesda help catch these early.

Can Saliva Help Heal Cavities?

Saliva can help heal very early stages of enamel damage but cannot heal a cavity once a hole has formed. Saliva contains calcium, phosphate, and other minerals that help remineralize weakened enamel. The NIDCR explains that saliva also helps wash away food particles and neutralize harmful acids. Once decay has broken through the enamel surface, only professional dental treatment can repair the damage.

How Late Is Too Late to Reverse a Cavity?

It is too late to reverse a cavity once the enamel has broken down and a hole has formed in the tooth. According to the NIDCR, only the earliest stage of decay (demineralization with white spots) can be reversed through fluoride treatment and improved oral hygiene. Once a cavity reaches the dentin layer, it must be treated with a filling or more advanced restorative dentistry.

Do Cavities Mean Bad Hygiene?

Cavities do not always mean bad hygiene. While poor brushing and flossing habits increase the risk, other factors also contribute. Genetics, dry mouth, the shape of your tooth grooves, medications, and diet all play a role. The CDC’s 2024 Oral Health Surveillance Report shows that even adults with good hygiene habits can develop cavities, particularly in hard-to-reach areas. That is why professional exams and cleanings are essential.

Is a Cavity a Black Hole?

A cavity is not always a black hole. In its earliest stages, a cavity may appear as a white or light brown spot on the tooth surface. As decay progresses, the spot may darken to brown or black. Some cavities form between teeth and are only visible on dental X-rays, which is why we use digital imaging during exams at our Bethesda office.

Where to Go From Here

Cavities are one of the most common health conditions in the world, but they are also one of the most preventable. The earlier decay is caught, the simpler treatment will be. Waiting too long turns a small filling into a crown, a root canal, or even an extraction.

At Dentistry of Bethesda, Dr. Hornstein and our team take a preventive-first approach to dental care. We use advanced diagnostic tools like DIAGNOdent, digital X-rays, and intraoral cameras to detect decay at its earliest stages. Whether you need a routine cleaning, a filling, or a more complex restoration, we are here to help patients throughout Bethesda, Silver Spring, Chevy Chase, Rockville, and Potomac.

Call us at (301) 530-2700 to schedule your appointment today.