What Is a Cavity?
A cavity is a hole in a tooth caused by decay. It forms when acids slowly break down the hard outer layer of the tooth, called enamel. Dental caries, the clinical name for tooth decay, is one of the most common chronic diseases in the world [10].
Cavities form through a process called demineralization. Bacteria in plaque feed on sugar and release acid. That acid pulls minerals out of the tooth surface. Over time, the weakened spot collapses into a visible hole [10]. This process can affect any tooth, including the chewing surfaces of back teeth and the smooth sides between teeth.
Many cavities cause no pain in the early stages. A person may have a cavity for months before they notice tooth sensitivity or cavity symptoms. This is why the signs of a cavity are easy to miss without a dental exam. Routine checkups allow your dentist to catch dental cavities while they are small.
What Causes Cavities and Who Is at Risk?
Cavities form when acid repeatedly attacks the tooth surface faster than saliva can repair it. Diet, oral hygiene, saliva flow, and certain health conditions all change how quickly tooth decay develops [10].
Diet and Bacteria
Sweet foods and sugary drinks feed the bacteria that produce acid. The more often you eat or sip sugar, the more acid attacks the tooth structure [10]. Frequent snacking is harder on teeth than one larger serving because each exposure restarts the acid attack.
Poor brushing and flossing let plaque build up along the gumline and between teeth. This raises the risk of both tooth decay and gum disease [4].
Acid From the Stomach
Stomach acid can also wear away enamel. Gastroesophageal reflux disease, often called GERD, allows acid to reach the mouth and dissolve the tooth surface [8]. People with frequent reflux may notice worn, sensitive teeth.
Eating disorders that involve repeated vomiting expose teeth to stomach acid as well. A systematic review of oral and dental signs found that erosion and decay are common in people with eating disorders [1].
Other Risk Factors
Dry mouth lowers saliva, which normally washes away acid and helps rebuild enamel. Many medications reduce saliva. Deep grooves on chewing surfaces, exposed roots, and older fillings also trap plaque and raise risk [10]. Children and older adults tend to be more vulnerable to cavities.
Signs of a Cavity and How It Is Diagnosed
The signs of a cavity range from no symptoms at all to sharp pain. Common cavity symptoms include tooth sensitivity, a visible hole or dark spot, and pain when you bite [10]. A dentist confirms decay with an exam and X-rays.
What Patients Notice
Early signs are often mild. The first hint may be tooth sensitivity to sweet foods, hot drinks, or cold air. You might see a white, brown, or black mark on the tooth surface before any hole appears [10]. White spots show that minerals have started to leave the enamel.
As decay grows, you may feel a visible hole with your tongue or see one in a mirror. Cavity pain can become a dull ache or a sharp pain when you chew. Pain that lingers, throbs, or wakes you at night may mean the decay has reached the nerve inside the tooth [9]. A cracked tooth can cause similar pain, so an exam is needed to tell them apart.
How Dentists Diagnose Cavities
Your dentist looks at and gently checks each tooth, then uses dental X-rays. Radiographs reveal decay between teeth and under fillings that a visual exam cannot find [7]. This makes X-rays a key tool for early detection.
Newer tools are being studied to support diagnosis. An umbrella review of artificial intelligence in caries detection found that AI software can help dentists read images and spot decay, though it works alongside the dentist rather than replacing clinical judgment [2].
When to Seek Care
See a dentist if you have ongoing tooth sensitivity, a visible hole, or any cavity pain. Get care sooner if pain is severe, the tooth throbs, or your face or gum swells. Swelling can signal a tooth abscess, which is an infection that needs prompt treatment [11].
Treatment Options for Cavities
Treatment depends on how deep the decay reaches. Small cavities are removed and sealed with a filling. Deeper decay near the nerve may need root canal therapy to save the tooth [4][6].
Fillings for Small Cavities
When a cavity is limited to enamel or the layer just beneath it, the dentist removes the decay and fills the space. Expert consensus on caries management supports removing only the decayed tissue and restoring the tooth to protect the remaining tooth structure [4]. Fillings restore the chewing surface and stop further decay.
Treatment for Deep Decay
When decay reaches close to the pulp, the soft tissue with nerves and blood vessels, the dentist tries to keep the pulp alive when possible. A systematic review and meta-analysis of deep caries in immature permanent back teeth found that vital pulp treatments can preserve a healthy pulp in many cases [6]. Keeping the pulp alive can avoid more involved treatment.
Root Canal Therapy
If the pulp is infected or dying, the tooth may need root canal therapy. During treatment, the dentist or endodontist removes the diseased pulp, cleans the canals, and seals them. Root canals let you keep a tooth that would otherwise be lost [11]. A systematic review of periapical healing reported high healing rates after root canal treatment, with outcomes similar across several modern sealers [5].
Symptoms guide this choice. Research correlating clinical and tissue diagnoses shows that lasting, spontaneous pain often reflects pulp damage that needs root canal therapy rather than a simple filling [9]. After root canals, the tooth usually needs a crown to protect it.
Recovery and Aftercare
Recovery is usually quick. After a filling, numbness fades in a few hours, and mild tooth sensitivity may last a few days. After root canal therapy, soreness typically settles within days as the area heals [11].
What to Expect
Some sensitivity to hot, cold, or pressure is normal at first. Over-the-counter pain relievers usually control it. Chew on the other side until the tooth feels normal, especially after a deep restoration or a crown.
Healing after root canals continues below the surface. Studies that track the bone around the root show that the area heals over months in most cases [5]. Your dentist may take a follow-up X-ray to confirm healing.
Follow-Up and Prevention
Keep your regular checkups so your dentist can watch the treated tooth and catch new decay early. To prevent cavities, brush twice a day with fluoride toothpaste, clean between teeth daily, and limit how often you eat sweet foods [4]. These habits also lower your risk of gum disease.
Cost Factors for Cavity Treatment
Cavity treatment cost depends on the size and depth of the decay. A simple filling is usually the least expensive option, while root canal therapy plus a crown costs more. Costs vary by location, provider, and case complexity.
The deeper a cavity goes, the more treatment it needs, so early detection often keeps costs lower. A small cavity caught early may need only a filling. The same tooth left untreated may later need root canals, a crown, or removal, which adds cost and visits.
Many dental plans cover a share of fillings and root canal therapy, though coverage levels differ by plan. Ask your dental office for a written estimate before treatment, and ask whether they offer payment plans. Verify what your specific insurance covers, since benefits vary widely between policies.
General Dentist or Endodontist?
A general dentist diagnoses cavities, places fillings, and performs many root canals. An endodontist is a dentist with extra training in treating the pulp and saving teeth, and is often the right choice for complex cases [11].
Your dentist may refer you to an endodontist when a tooth has curved or narrow canals, has had a failed prior root canal, or has unclear cavity pain that is hard to diagnose. Endodontists use magnification and detailed imaging to treat these cases. For deep decay or lasting pain, this added expertise can improve the odds of saving the tooth [9].
Both options aim to remove disease and keep your natural tooth when possible. The best choice depends on the tooth, the difficulty of the case, and your dentist's judgment. You can learn more about this field on the endodontics page.
Find an Endodontist Near You
If you notice the signs of a cavity, such as tooth sensitivity, a visible hole, or cavity pain that will not go away, get an exam soon. Early detection keeps treatment simpler and helps you keep your natural tooth. Use My Specialty Dentist to find an endodontist near you and compare providers who treat deep decay and perform root canal therapy.
Search Endodontists in Your Area
