Pain is a late symptom. By the time a tooth aches, decay has usually reached well past the enamel and the treatment needed is correspondingly bigger.
The useful signs come much earlier, and they are quiet.
What decay actually is
Plaque bacteria produce acid, and that acid dissolves mineral out of the enamel. At first the damage is microscopic and the surface is still intact. Given time, the surface collapses and a cavity forms.
Caught in the first phase, it can sometimes be arrested or reversed with fluoride and better cleaning, with no drilling at all. Caught later, it means a filling. Later still, a crown or root canal treatment.
The gap between those outcomes is almost entirely a question of timing.
Five early signs
Short, sharp sensitivity to cold or sweet. A quick jolt that fades within a second or two. Sensitivity that lingers for minutes is a different signal and warrants a prompt look.
Chalky white patches. Early demineralisation shows as a matte, opaque white mark, often near the gum line. The surface is still intact at this stage, which is exactly why it is worth catching.
Dark staining deep in a groove. Back teeth have deep fissures. Staining that sits down inside one and does not brush away is worth checking — though plenty of dark grooves are only stain.
Food catching in the same spot. Repeatedly trapping food in one place often means a cavity has opened up between two teeth, where you cannot see it.
A rough patch your tongue has started finding. A surface that was smooth and now is not has changed for some reason.
What is usually not decay
- General yellowing, which is normal dentine colour showing through
- Surface staining from tea, coffee or red wine
- Brief sensitivity for a few days after whitening
Discolouration and decay are not the same thing, and the two get confused constantly.
Why early matters
A small cavity is quick to treat, removes less tooth, and the repair tends to last longer. A large one weakens the remaining tooth structure, may need a crown rather than a filling, and sometimes reaches the nerve — at which point root canal treatment enters the picture.
None of that is an argument for anxiety. It is an argument for being looked at before symptoms arrive, which is most of what a routine examination is for.
Decay rarely appears suddenly. It announces itself quietly first, and the whole value of catching it then is how much less has to be done about it.
