Overview
Germs in plaque, a sticky film on teeth, feed on sugar and make acid. The acid pulls minerals out of the tooth's hard outer layer (enamel). Saliva and fluoride can put minerals back.
When more minerals are lost than replaced, a white spot appears, then a hole forms. Without treatment, decay can reach the nerve and cause pain, infection, and tooth loss. Cavities and gum disease are the top causes of lost teeth.
Symptoms
Early decay often has no symptoms.
- Toothache or a tooth sensitive to hot, cold, or sweets
- White, brown, or black spots on a tooth
Less common
- A hole you can see or feel
- Pain when biting
- Bad breath
- Swelling of the gum, face, or jaw from an abscess
Look up a symptom: Badly decayed or broken teeth with a very dry mouth · Toothache or tooth sensitive to hot, cold, or sweets
When to get medical care
Causes
Decay happens when mouth germs turn sugars into acid. Frequent snacking and sugary drinks, little fluoride, and dry mouth make it more likely.
Does it spread or run in families?
- It isn't caught from someone else. It's caused by germs that already live on or in the body.
Who is more likely to get it
- Sugary drinks and frequent snacks
- Not enough fluoride
- Dry mouth, from medicines or other conditions
- Babies who go to bed with a bottle of milk or juice
- Gums pulling back, which exposes tooth roots
Possible complications
- Tooth abscess: A pocket of pus from infection
- Inflamed tooth nerve: Can need a root canal
Diagnosis
A dentist finds decay during a checkup.
Questions you may be asked
- Whether teeth hurt or feel sensitive
- How often you eat sweets or drink sugary drinks
- Whether you use fluoride toothpaste or drink tap water
The exam
The dentist looks at and gently probes each tooth.
Tests
Tests:
- Dental X-rays: Find decay between teeth and under fillings.
Treatment
Treatment depends on how deep the decay goes.
Self-care
- Brush twice a day with fluoride toothpaste
- Clean between your teeth every day
- Cut back on sugary drinks and snacks
- Rinse with water after sweets if you can't brush
- For pain until you see a dentist, use an over-the-counter pain reliever
Medicines
Fluoride is the main medicine for preventing and stopping decay.
| Medicine | Helps with | Good to know |
|---|---|---|
| Fluoride | Strengthening enamel and reversing early decay | Use a rice-grain smear of toothpaste for children under 3 and a pea-size amount for ages 3 to 6. |
| Silver diamine fluoride | Stopping decay, especially in young children | Turns decayed spots black. |
| Pain relievers | Toothache until treatment |
OwieClear doesn't give doses: follow the label or your healthcare professional. Medicine names here are examples, not a full list.
Early decay can be reversed with fluoride varnish. A cavity needs a filling. Deep decay may need a crown or a root canal. A badly damaged tooth may need to be pulled.
Prevention
Most tooth decay can be prevented:
- Brush twice a day with fluoride toothpaste
- Drink fluoridated tap water
- Limit sugary drinks and snacks
- Get dental sealants for children's back teeth
- See a dentist regularly
Which doctor treats this
- Start with your dentist.
Back to school, work, or sports
- Most people can go back to school or work the same day or the next day.
Children, pregnancy, and older adults
- Babies and toddlers: Wipe gums and brush the first tooth. Don't put a baby to bed with a bottle.
- Older adults: Dry mouth from medicines and gum recession raise the risk.
Pregnancy and breastfeeding
- If you're pregnant or planning to be, tell your prenatal provider about this condition.
- Some infections can pass to the baby during pregnancy or birth. Tell your provider if you've been exposed.
- Don't start or stop any medicine on your own. Some are safe in pregnancy and some need to be changed.
- Ask before taking any pain reliever. The FDA advises avoiding ibuprofen and naproxen after 20 weeks unless your doctor says to.
- Breastfeeding: Most medicines are fine, but ask. The NIH LactMed database lists what's known about each one.
Outlook
Caught early, tooth decay can be stopped or reversed. Fillings and other treatments save most teeth.
Myths and facts
Myth: Cavities only happen to children.
Fact: Adults get cavities too, especially near the gums.
Getting ready for your visit
Tell the dentist what hurts and when.
What to bring
- A list of medicines
Questions to ask
- Do I need a filling, or can fluoride fix it?
- Would sealants help my child?
- How can I lower my risk of more cavities?
Research studies
Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.
Search ClinicalTrials.gov for studies on Tooth decay (cavity)
Sources
Last updated 2026-11-12.