Tooth decay (cavities): causes, treatment and prevention
What tooth decay is, why sugar frequency matters, the early signs, how fillings and root canal treatment work, and how to protect children's teeth.
Also known as: Cavities; Dental Caries; Dental Sealants; Plaque, Dental
What tooth decay is
Tooth decay, or dental caries, is damage to the hard surface of a tooth. Bacteria in plaque feed on sugars and other carbohydrates in food and drink and produce acid. Each time you eat or drink something sugary, the acid attacks the enamel for some time afterwards. Saliva and fluoride repair early damage, but when acid attacks happen too often, the enamel breaks down and a hole (cavity) forms.
Decay is the most common health condition in the world and affects children and adults. Early decay can be stopped and even reversed. Once a cavity forms it does not heal by itself; left untreated, decay spreads into the soft inner part of the tooth (the pulp), causing pain, infection and abscesses, and eventually tooth loss.
Symptoms
Early decay often causes no symptoms. As it progresses, you may notice:
- Toothache, which may come and go or be constant
- Sensitivity to sweet, hot or cold food and drink
- White or brown spots on the teeth, or dark staining
- Visible holes or pits in the teeth
- Pain on biting
- Swelling of the gum or face, bad taste, or pus — signs of an abscess
In young children, decay often starts on the upper front teeth as white chalky lines near the gum, then brown patches. Children may simply refuse food, sleep badly or be irritable.
Causes and who is at risk in India
- Frequent sugar — sweets, biscuits, chocolates, sugary tea and coffee, soft drinks, packaged juices and sticky snacks between meals. How often you have sugar matters more than how much
- Putting a baby to sleep with a bottle of milk, juice or sweetened liquid, or prolonged night-time feeding after teeth appear
- Not brushing twice a day with fluoride toothpaste
- A dry mouth from medicines, illness or tobacco
- Receding gums in older adults, which expose softer roots
- Deep grooves in back teeth that trap food
- Not visiting a dentist until there is pain
Decay in baby teeth matters. These teeth hold space for adult teeth, help with eating and speech, and infection in them can affect the adult teeth developing underneath.
How it is diagnosed
- Dental examination — the dentist looks for spots, soft areas and holes, and asks about pain and sensitivity
- Dental X-rays — show decay between teeth and under fillings that cannot be seen, and whether infection has reached the root
Regular check-ups find decay early, when treatment is simpler, quicker and cheaper, sometimes without a drill at all.
Which dentist to see
A dentist diagnoses and treats tooth decay. Children may be seen by a paediatric dentist (pedodontist). A child's first dental visit is often advised around the time the first tooth appears or by the first birthday, and a paediatrician can also check children's teeth during routine visits.
You can find dentists in Bengaluru or paediatricians in Bengaluru on The Doctor Index, each with a registration you can check.
Treatment
- Fluoride treatment — for early decay, fluoride varnish or gel applied by the dentist, with fluoride toothpaste at home, can help enamel repair itself.
- Fillings — the decayed part is removed and the hole filled with tooth-coloured composite, glass ionomer or other materials.
- Root canal treatment — when decay reaches the pulp, the infected tissue is removed, the canals cleaned and sealed. This saves the tooth and relieves pain. A crown is often placed afterwards to protect it.
- Crowns — caps that cover a badly broken-down tooth.
- Tooth extraction — when a tooth cannot be saved. The gap can be filled with a bridge, denture or implant.
- Fissure sealants — a protective coating painted onto the grooves of children's back teeth to prevent decay.
Painkillers may ease toothache for a short while but do not treat the cause, and antibiotics alone do not cure a decayed tooth. Clove oil and home remedies are not a substitute for treatment. If antibiotics are prescribed for a spreading infection, take them as directed and still have the tooth treated.
Prevention
- Brush twice daily — last thing at night and one other time — with fluoride toothpaste. Spit out, do not rinse with water afterwards
- For children under three, use a smear of fluoride toothpaste; from three to six, a pea-sized amount, with an adult brushing or supervising
- Keep sugary food and drinks to mealtimes; choose water, plain milk, fruit and nuts as snacks
- Do not put babies to bed with a bottle of anything other than water
- Visit the dentist regularly, even without pain
- Ask about fissure sealants and fluoride varnish for children
- Avoid tobacco and areca nut
Chewing sugar-free gum after meals increases saliva, which helps neutralise acid. Sweetened medicines and syrups given to children often can also contribute to decay; ask your doctor or pharmacist about sugar-free versions.
When it is an emergency
Call 112 or 108, or go to the nearest emergency department, for:
- Facial swelling that is spreading towards the eye or neck
- Difficulty swallowing, breathing or opening the mouth
- Toothache with high fever and feeling very unwell
Severe toothache or a gum swelling without these signs needs a dentist within a day or two.
Questions to ask at your appointment
- How many teeth are affected, and how deep is the decay?
- Can early decay be treated without a filling?
- Which filling material do you recommend, and why?
- Does this tooth need root canal treatment, and will it need a crown?
- Are sealants or fluoride varnish suitable for my child?
- How often should we come for check-ups?
Common questions
Questions people ask
- Do baby teeth with cavities need treatment?
- Yes. Decayed baby teeth can cause pain, infection and difficulty eating, and infection can affect the adult teeth growing underneath. Early loss of baby teeth can also cause crowding later. A dentist can treat them, often simply if found early.
- Is root canal treatment painful?
- Root canal treatment is done under local anaesthetic and usually feels similar to having a filling. It relieves the severe pain caused by an infected tooth. Some tenderness for a few days afterwards is normal and settles with simple pain relief your dentist advises.
- Is fluoride toothpaste safe for children?
- Yes, in the right amount. Fluoride strengthens enamel and is one of the most effective ways to prevent decay. Use a smear for children under three and a pea-sized amount for older children, supervise brushing, and teach them to spit rather than swallow.
- Can a cavity heal on its own?
- Very early decay, seen as white spots, can be stopped and partly repaired with fluoride and less frequent sugar. Once a hole has formed, it cannot heal itself and needs a filling or other treatment before it grows deeper.
This condition is usually assessed by a dentist. Every profile shows the doctor’s registration and what has been checked.
Dentists in Bangalore
A few dentists listed on The Doctor Index. They are shown because of their speciality, not a stated interest in Tooth Decay; ask the clinic whether the doctor sees it.
Related conditions
Practical reading
All postsSources
- MedlinePlus, US National Library of Medicine — Tooth Decay
- World Health Organization — Oral health fact sheet
- MedlinePlus, National Library of Medicine — Tooth Decay — Public-domain health-topic summary
Tooth decay (cavities): causes, treatment and prevention is original text by The Doctor Index; the compiled source draft was used for research. Source: MedlinePlus, National Library of Medicine. Orphadata Science: Free access data from Orphanet. © INSERM 1999; July 2026 data, CC BY 4.0. This product uses the Human Phenotype Ontology (hp/releases/2026-09-01). Only sources listed for this article apply. Source material has been selected and arranged; HPO definitions are reproduced without alteration. No source organisation endorses this compilation. Köhler S et al. The Human Phenotype Ontology project: linking molecular biology and disease through phenotype data. Nucleic Acids Research 2014;42(D1):D966–D974. doi:10.1093/nar/gkt1026.
General information, not advice about your situation. Errors can be reported through the corrections process. Reference TDI-C-2334.