You cannot reliably see or feel your own cavities, because the places they start most often are the places you cannot inspect and cannot feel. A large share of decay begins between two teeth, where the surfaces touch, hidden from view and with no nerve supply in the outer layer to report it. By the time a cavity announces itself, it is rarely early. This is what a check-up and an X-ray are actually for.
If it has been a while, a check-up will tell you what is there rather than what you can see.
Call (02) 9649 6468 · Book online · WhatsApp
Why can't you see your own cavities?
Three reasons, and none of them are about how carefully you look.
The starting points are hidden
Decay favours the places that are hard to clean, which are also the places that are hard to see: between the teeth where they touch, deep in the grooves on the chewing surfaces of back molars, and at the margins of existing fillings. Only the chewing surfaces are visible at all in a mirror, and even those grooves can be narrower at the surface than the cavity beneath them.
Early decay does not look like a hole
It looks like nothing, then like a dull chalky patch, then like a faint shadow. A dark spot is not automatically a cavity, and a cavity is very often not a dark spot. Distinguishing between staining, an old sealant, an arrested lesion and active decay is a clinical judgement made with drying, light and instruments.
Enamel has no nerve supply
Nothing in the outer layer of a tooth can produce a sensation. Decay confined to enamel is silent by definition. Sensation only begins once the process reaches the dentine underneath, which is already some distance in.
What does an X-ray find that you can't?
Bitewing X-rays are taken specifically to look at the surfaces between teeth and beneath existing fillings. On a bitewing, decay appears as a darker wedge in an otherwise uniform structure, and its depth can be measured against the enamel and dentine layers.
This matters because the treatment decision depends on depth. Decay that has not yet broken the surface can sometimes be halted with fluoride and changed habits. Decay a third of the way through dentine is a filling. Decay approaching the nerve is a different conversation entirely.
An X-ray also shows what is happening under a filling placed years ago — an area no examination, no matter how careful, can inspect from above.
At Berala Dental, a check-up, X-rays and clean is $250. Included in that fee are 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. As a market reference, an OPG is commonly charged separately, often around $125, with individual X-rays around $49 each. All figures assume no health fund contribution; yours may pay part of it depending on your policy.
Not sure whether that dark spot is decay or staining? That is exactly what a check-up settles.
Call (02) 9649 6468 · Book online · WhatsApp
What do the earliest signals actually feel like?
Subtle enough that almost everyone dismisses them. These are the ones worth paying attention to:
- Food catching in the same spot every time. One of the most reliable early signs of decay between two teeth, because the cavity has changed the shape of the contact point. If floss shreds in the same place repeatedly, that is the same signal.
- A brief twinge on cold or on something sweet that disappears the moment the trigger is gone. Short and forgettable, but it means dentine is involved.
- Chewing on one side without having decided to. People often notice this only in hindsight.
- A rough edge your tongue keeps returning to.
- An unpleasant taste or persistent bad breath from one area.
- Sensitivity that has changed character — lingering after the trigger, or responding to heat rather than cold. This one is different in kind. Pain that lingers, wakes you, or responds to hot suggests the nerve is inflamed rather than irritated, and it should be looked at promptly.
The pattern to notice across all of these is that they are episodic. They come and go, which is exactly why they get filed under "it settled down".
What happens between check-ups?
Decay does not move at a fixed speed. It depends on how often acid is produced, how well saliva buffers it, whether fluoride is present, and how well the site can be cleaned. Some lesions barely change in three years. Others cross from enamel into dentine in a matter of months, particularly in children, whose enamel is thinner.
This variability is the reason recall intervals are set individually rather than universally. Someone with no decay history, good cleaning and a low-sugar diet is genuinely low risk. Someone with several recent fillings, a dry mouth from medication, or frequent sugary drinks is not, and a six-month interval may be too long for them.
If a lesion is found early and monitored, the interval also becomes the thing that catches it. "We will keep an eye on that one" only works if there is a next appointment.
Can you do anything about a cavity yourself?
You can influence whether early decay progresses. You cannot restore a cavity once the surface has broken, and no product available to a consumer does that.
- Reduce frequency, not just quantity. Sipping one soft drink across three hours does more damage than drinking it in ten minutes.
- Fluoride toothpaste twice daily, and spit rather than rinse. Rinsing washes away the fluoride that was about to do the work.
- Clean between the teeth daily. This is the single most targeted thing available, because it addresses the exact site where most hidden decay begins.
- Water between meals.
- Fissure sealants for deep grooves, which cover the surface without any drilling.
For what is happening structurally at each stage of the process, see how far tooth decay goes before you feel it.
Quick answers
Can I have a cavity and not know it?
Yes, and it is the usual situation. Enamel has no nerve supply, and most decay starts between the teeth where it cannot be seen. Cavities are commonly found at a check-up before they have caused any symptom at all.
Is a black spot on my tooth always a cavity?
No. Staining, an old sealant, and decay that has stopped progressing can all look similar. Equally, active decay is often not dark at all. Telling them apart needs examination rather than inspection in a mirror.
How often should I have X-rays?
It depends on individual risk rather than a fixed schedule — decay history, diet, existing fillings, and whether previous X-rays showed anything being monitored. The interval is set by the clinician for the individual.
Can a cavity heal on its own?
Only before the surface breaks. Early demineralisation can remineralise with fluoride and better cleaning. Once a hole has formed, the lost structure does not regenerate and it needs restoring.
The point of a check-up
A check-up exists to find the things that produce no symptoms, in the places you cannot inspect. That is the whole job, and it is why waiting until something hurts is the most expensive way to manage teeth.
Berala Dental has looked after Berala families since 2002, and no question is a silly one.
Call (02) 9649 6468 · Book online · WhatsApp
You can also read about check-ups and cleans, tooth-coloured fillings, whether dental X-rays are safe, or how our fees work. healthdirect publishes general information on tooth decay.
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.
BeralaDental