What decay is
Decay is not a "worm" and not a hole that appears by itself. It is enamel and dentine dissolving in acid produced by bacteria in your mouth. The bacteria feed on the sugar and starch you eat, and for 20–40 minutes after every meal they release acid. The acid pulls minerals out of the enamel; between meals saliva puts them back. While dissolving and repair are in balance, the tooth stays healthy. When acid attacks come more often than repair can keep up with, decay begins.
Why some people get it and others do not
- How often you eat. Not how much sugar, but how many times a day. A sweet every hour is worse than cake after lunch. Sipping sweetened coffee or lemonade all day is the same.
- Saliva. Less saliva (medication, stress, mouth breathing at night) means less protection.
- Tooth shape. Deep grooves on chewing surfaces and tightly packed teeth trap plaque the brush cannot reach.
- Fluoride. Fluoridated enamel dissolves more slowly. That is why fluoride toothpaste and fluoride at the hygienist work.
- Hygiene. Plaque left for 24 hours becomes more acidic and sticks harder. Twice a day is the minimum; evening flossing is what most people skip.
The four stages
1. White spot
Enamel has lost minerals but the surface is still intact. Looks like a matt white or brownish patch, usually near the gum or between teeth. No pain. This stage can be reversed: fluoride, hygiene and fewer sugary snacks let the enamel repair itself. No drilling.
2. Enamel caries
The surface has broken and a small cavity has formed in the enamel. Usually painless, sometimes sensitive to sweet. Needs a small filling; the sooner, the smaller.
3. Dentine caries
Bacteria have reached the dentine, which is softer, and spread faster there than in enamel; the cavity inside is bigger than it looks outside. Pain from sweet and cold, food gets stuck, breath may turn unpleasant. Needs a filling, or an inlay for large cavities.
4. Deep caries
A thin layer of dentine, or nothing, is left before the nerve. Pain lingers after cold and heat and wakes you at night. If the nerve is still healthy, a filling with a protective liner; if inflamed, root canal treatment. Untreated, a pus-filled infection in the bone and loss of the tooth.
Why the X-ray matters
Decay between teeth, the most common kind in adults, is invisible to the eye until it reaches dentine. On an X-ray it shows as a dark patch already at the enamel stage. A check-up with X-rays every 1–2 years (10–15 EUR per image) saves more than it costs.
Decay in children
Milk-tooth enamel is thinner and decay spreads twice as fast. The most common cause in toddlers is a bottle of sweet drink or milk at night. Milk teeth are treated (50–60 EUR per filling) because untreated decay hurts and infects the permanent tooth underneath. First dental visit around the first birthday, then every six months.
How to stop decay while it is a spot
- Fluoride toothpaste at 1350–1500 ppm twice a day; do not rinse afterwards, so the fluoride stays on the teeth.
- Sweets only with meals. Between meals, water, not juice or sweetened coffee.
- Floss or an interdental brush in the evening.
- Professional cleaning and fluoride every six months.
- Sugar-free gum after eating stimulates saliva.
When you need the dentist
As soon as a spot has become a hole or a tooth reacts to sweet and cold. Treatment at that stage is one visit and a filling for 90–130 EUR; waiting turns it into root canal treatment at 120–320 EUR plus a filling, and later a crown. How treatment works and all prices on the cavity treatment page. Book: +371 22428688.
