Tooth Decay: Stages, and Can a Cavity Heal?

How tooth decay starts

Tooth decay is a slow process, and it begins with bacteria that live in plaque, the soft film on your teeth. Each time you eat or drink something with sugar or refined starch, those bacteria make acid. For a while after, the acid pulls minerals such as calcium and phosphate out of the enamel.

Saliva slowly neutralizes the acid and puts some minerals back, especially when fluoride is around. Tooth decay happens when the loss wins over the repair, again and again, for months. That is why how often you have sugar matters more than how much you have at one time.

The stages of tooth decay

Dentists describe decay as a process rather than an on-off switch. These are the usual stages:

• Stage 1, white spot: a dull, chalky patch where enamel has lost minerals. No hole yet, and usually no pain.
• Stage 2, enamel breakdown: the surface weakens and may turn light brown. A small cavity can start to form.
• Stage 3, dentin decay: decay reaches the softer, yellow layer under the enamel and spreads faster. Sensitivity to sweets or cold often begins here.
• Stage 4, pulp involvement: bacteria reach the nerve in the centre of the tooth. This can cause lasting or throbbing pain.
• Stage 5, abscess: infection spreads past the root tip into the bone, which may cause swelling, a gum boil or fever.

Can a cavity heal? The honest answer

At stage 1, yes, in a sense. A white spot can remineralize, meaning minerals return and the enamel hardens again. The spot may stay visible, but it can stop getting worse. Your dentist may decide to watch it and check it at your next visit.

Once the enamel has broken down into a hole, it can't grow back. Enamel has no living cells to repair itself. The decay inside will usually keep spreading until a dentist removes it. A filling cleans out the soft decay and seals the space. The earlier this happens, the smaller and simpler the filling tends to be.

Hidden decay between teeth or under fillings is a topic on its own. Our article on the signs of a cavity you cannot see covers it.

Natural ways to heal cavities: what helps and what doesn't

Many websites promise natural ways to heal cavities. Some advice is sensible; some has no good evidence. For early white-spot decay, these steps are backed by mainstream dental advice:

• Brush twice a day with fluoride toothpaste, and spit rather than rinse afterward so the fluoride stays on your teeth.
• Keep sugary foods and drinks to mealtimes rather than sipping or snacking all day.
• Drink tap water between meals. Many Ontario communities add fluoride to tap water; your local public health unit can tell you about yours.
• Clean between teeth once a day.
• Chew sugar-free gum after meals to boost saliva, if your jaw is comfortable with it.
• Ask your dentist whether in-office fluoride varnish or a higher-fluoride product makes sense for you.

Claims to be careful with

Oil pulling, special diets, herbal powders and fluoride-free 'remineralizing' pastes are often sold as cavity cures. There is no reliable proof they reverse a true cavity. Waiting on them while decay grows can turn a small filling into a root canal or an extraction. If something sounds too good to be true, ask your dentist before you rely on it.

Black spot on tooth: is it decay?

A black spot on a tooth can mean several things. It might be an active cavity. It could also be a stain from coffee, tea or tobacco caught in a groove, or an old area of decay that hardened and stopped, called arrested decay. Tartar near the gumline can look dark too, and an old amalgam filling can show through as a grey shadow.

You can't tell these apart by looking in a mirror. A dentist checks the surface, may take an X-ray, and can use an intraoral camera to show you the spot up close. Some dark spots just need watching. Others need a small filling.

Cavity pain relief while you wait

If a cavity is causing pain, these steps may help for a short time. They don't stop the decay.

• Avoid very cold, hot or sweet food and drinks, and chew on the other side.
• Gently floss in case food is packed into the hole, then rinse with warm water.
• An over-the-counter pain reliever may help; use it only as directed on the package, and ask a pharmacist if it's safe with your other medicines.
• Don't place tablets on the tooth or gum. Don't use antibiotics that weren't prescribed to you; they don't treat decay.

Getting decay checked

Pain that lingers, wakes you up or comes with swelling needs a prompt dental visit. Swelling that affects breathing or swallowing needs 911 or the emergency department. If you're in Aurora or nearby, Aurora Gateway Dental Care can check a worrying spot, explain the stage it's at and walk you through options, with a written estimate before treatment. Call 289-475-5497.

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