Stages of decay and treatment
| Stage | What you may notice | Treatment |
|---|---|---|
| Early (white spot) | Nothing, or a chalky white patch | Fluoride, better cleaning, less frequent sugar |
| Into enamel | Often nothing; sometimes a dark spot | Small filling |
| Into dentine | Sensitivity to sweet, cold or hot | Filling |
| Near the nerve | Lingering pain, pain at night | Deep filling with a lining, or a root canal |
| Nerve infected | Throbbing, swelling, pain on biting | Root canal and crown, or extraction |
Common causes
- Frequent sugar. How often matters more than how much: sipping sweet chai or soft drinks through the day keeps teeth under acid attack.
- Sticky snacks such as toffees, biscuits and dried fruit between meals.
- Not cleaning between the teeth, where many cavities start.
- A dry mouth, from some medicines, mouth breathing or illness.
- Receding gums, exposing softer roots.
- Old fillings with leaking edges.
How to prevent cavities
- Brush twice a day with a fluoride toothpaste; spit, don’t rinse.
- Clean between your teeth every day.
- Keep sugary food and drinks to mealtimes.
- Drink water between meals.
- Have a check-up every six to twelve months, more often if you get a lot of decay.
- Ask about fissure sealants for children’s back teeth.
At Petal Smiles
Our general dentist finds and treats decay early, often with a single small tooth-coloured filling, and Dr. Adish provides root canal care when decay has affected the pulp and the tooth can be restored. We’re open 10am to 8pm every day. See fillings and dental check-ups.
Questions patients ask us
Can a cavity heal on its own?
Very early decay, a white chalky spot with no hole yet, can harden again with fluoride and better habits. Once there's a hole, it won't heal and needs a filling.
Does a cavity always hurt?
No. Many cavities cause no pain until they're deep. Sensitivity to sweet or cold is often the first sign.
How fast does a cavity grow?
It varies. Through enamel it can take months to years; once it reaches the softer dentine underneath, it can spread faster, especially with frequent sugar.
What is the black spot on my tooth?
It may be a stain in the grooves, or decay. Only an examination, and sometimes an X-ray, can tell.
Are cavities contagious?
The bacteria that cause decay can be passed on, for example from parent to baby by sharing spoons. That's one reason to avoid tasting a baby's food from the same spoon.
Sources
NHS: tooth decay ↗ADA MouthHealthy: tooth decay ↗Last updated 24 October 2026.