Tooth decay is usually painless until it reaches the nerve, and by that point it has been developing for a long time. Enamel has no nerve supply, so damage there causes no sensation at all. Pain generally arrives only once decay has passed through enamel, crossed the softer dentine beneath, and approached the pulp. This is why decay found at a check-up is often a surprise.
If a tooth has started hurting, we can find out what stage it has reached.
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How decay actually starts
Bacteria live in everyone's mouth. Some of them feed on sugars and carbohydrates from food and drink, and produce acid as a by-product.
That acid dissolves minerals out of enamel. Saliva then works to replace them, helped considerably by fluoride. Every day is a contest between the two, and for most people it stays roughly balanced.
Decay happens when the balance tips — not usually from one large sugary event, but from frequency. A can of soft drink over ten minutes produces one acid attack. The same can sipped across three hours produces a sustained one, with no recovery time between.
The stages, and what each one feels like
1. Early demineralisation — feels like nothing
A dull, chalky white patch appears where minerals have been lost. The surface is still intact. At this stage the process can genuinely be reversed with fluoride, better cleaning and reduced acid exposure. Nothing hurts, and most people never notice it.
2. Enamel cavity — still usually nothing
The surface breaks and a small hole forms. Enamel has no nerves, so there is still commonly no pain. This is where an X-ray earns its place: decay between teeth is invisible to the eye at this stage and shows clearly on a bitewing.
Treated now, it is generally a straightforward filling.
3. Into the dentine — the first signals
Dentine is softer than enamel and decay moves through it faster. It also connects to the nerve, so symptoms begin: sensitivity to cold or sweet things, a twinge that fades quickly, food catching in a particular spot.
These are easy to dismiss, and often are.
4. Reaching the pulp — unmistakable
Once bacteria reach the nerve, the pulp becomes inflamed. Pain lingers after the trigger is gone, may respond to heat, and can wake people at night. Treatment at this stage generally means root canal treatment or extraction.
5. Abscess
The nerve dies and infection travels out of the root end into surrounding bone. See the warning signs of a dental abscess.
Why waiting for pain is an expensive strategy
The cost of treating decay rises sharply with each stage, and so does what is lost.
Early demineralisation may need nothing more than fluoride and a change of habit. A small cavity is a filling — $250 to $450 at Berala Dental depending on size and position. Decay that reaches the nerve typically means root canal treatment at $1,600 to $2,200, usually followed by a crown at $1,500 to $1,800. The gap between the first and the last is considerable, and the tooth is progressively more compromised at each step.
A health fund may contribute to any of these, depending on your policy. A written quote is provided before treatment begins.
Not sure when your last check-up was? That is usually a sign it is time for one.
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What a check-up is actually looking for
Largely the stages that produce no symptoms. A visual examination finds decay on surfaces that can be seen; bitewing X-rays find it between teeth and under existing fillings, where the eye cannot reach.
At Berala Dental, a check-up, X-rays and clean is $250, and that fee includes three intraoral X-rays, an OPG for new patients and thereafter every two to five years depending on bone loss and periodontal status, intraoral photos, the clean itself and a fluoride treatment, plus a periodontal chart where the clinician judges one is needed.
What reduces the risk
- Reduce how often, not just how much. Frequency of acid exposure matters more than total quantity.
- Fluoride toothpaste twice daily. Spit, do not rinse — rinsing washes away the fluoride that was about to do the work.
- Clean between the teeth. A large share of decay starts where two teeth touch, which brushing cannot reach.
- Water between meals. Particularly instead of juice, cordial or soft drink.
- Fissure sealants for deep grooves on back teeth, which trap food and resist cleaning.
- Regular check-ups, because the treatable stages are the silent ones.
Quick answers
Can tooth decay be reversed?
Only at the earliest stage, before the surface breaks. Early demineralisation can remineralise with fluoride and improved cleaning. Once a cavity has formed, the lost structure does not grow back and needs restoring.
Why doesn't my cavity hurt?
Because enamel has no nerve supply. Decay confined to enamel is generally painless, and symptoms usually begin only once it reaches the dentine beneath.
How quickly does tooth decay spread?
It varies considerably with diet, saliva, fluoride exposure and cleaning. It moves faster through dentine than enamel, and faster in baby teeth because their enamel is thinner.
Do I need X-rays to find decay?
For decay between teeth or under existing fillings, generally yes — those surfaces cannot be seen directly. Bitewing X-rays are the standard way of checking them.
Having it checked
Decay found early is usually simple to deal with. Berala Dental has looked after Berala families since 2002, and no question is a silly one.
Booking a check-up is the simplest way to find decay while it is still small.
Call (02) 9649 6468 · Book online · WhatsApp
You can also read about tooth-coloured fillings, check-ups and cleans, or how our fees work.
Written and reviewed by Humzah Aly, Oral Health Therapist. This article is general information only and is not a substitute for personalised dental advice. Please see a dental practitioner to discuss what is right for you.
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