Why Your Dentist's X-Ray Screen Has Coloured Boxes on It

You’re in the chair, the dentist turns the monitor towards you, and your x-ray is covered in little rectangles: some red, some orange, maybe a yellow outline round the gum line. A week later you get a treatment plan for three fillings and a crown, and you’re wondering whether those boxes are the reason.

They might be. Those coloured highlights almost always come from AI software that scans the x-ray and marks areas it thinks are worth a closer look. The software doesn’t diagnose anything. Your dentist does that. It’s a second pair of eyes, and you’re entitled to ask what every single box means before you agree to pay for anything.

What the software actually is

Several companies sell AI dental x-ray tools, and UK practices are taking them up quickly. The names you’re most likely to come across:

Pearl got US FDA clearance for Second Opinion in 2022 and promoted it as the first AI cleared to spot several different conditions on dental x-rays. Medical devices sold in Great Britain need UKCA or CE marking, so a reputable tool in a UK practice should carry one of those. Each one takes the digital image straight from the x-ray sensor, runs it through a model trained on very large numbers of labelled x-rays, and draws a box or outline wherever it finds a pattern that looks like a known problem.

The colours depend on the vendor and on how the practice has set things up. Nobody has a national standard saying red means decay. Ask, because the dentist can tell you in ten seconds.

A box is a question, not an answer

Here’s the part that matters for your wallet. The AI is tuned to catch things, so it will sometimes flag a shadow that turns out to be nothing, or a tiny change in the enamel that doesn’t need a drill at all.

Take decay. On a bitewing x-ray (the small sideways ones of your back teeth), decay shows up as a darker patch. If that patch is only in the enamel, the hard outer layer, it can often be stopped with high-fluoride toothpaste and better cleaning between your teeth, then checked again at your next visit. Once it gets into the dentine underneath, a filling becomes much more likely. An AI box drawn round an enamel-only shadow and one drawn round a lesion halfway to the nerve can look almost the same on screen.

Your dentist is supposed to combine the box with what they see and feel in your mouth, your history, and how quickly your teeth have changed over the years. If they’ve done that, they’ll be able to explain why a given box became a line on your treatment plan. If they can’t explain it, that’s worth noticing.

A worked example

Say you’re 42, you’ve just paid £27.40 for an NHS Band 1 check-up in England (the April 2025 rate; check nhs.uk for the current one), and the dentist hands you a plan. The AI report attached to your notes might look something like this. It’s an illustration of the usual layout, not output from any particular product:

Patient X-ray analysis — Bitewings L/R
Tooth 16  Caries (distal)        Enamel        Confidence: moderate
Tooth 26  Caries (mesial)        Dentine        Confidence: high
Tooth 36  Existing restoration   Margin defect  Confidence: moderate
Tooth 46  Calculus               Interproximal  Confidence: high
Bone level: 1.5–2.0 mm from CEJ, within normal range

UK dentists usually number teeth with a two-digit system. The first digit is the quarter of your mouth (1 upper right, 2 upper left, 3 lower left, 4 lower right) and the second counts back from the middle, so 26 is your upper left first molar and 36 is the lower left one.

Now the treatment plan:

• Filling on 16
• Filling on 26
• Replace filling on 36
• Scale and polish

On the NHS in England, that whole lot sits inside one Band 2 charge, £75.30 at the April 2025 rate, however many fillings there are. Done privately, white composite fillings tend to cost somewhere between £90 and £250 each depending on size and where you live, so three of them plus a hygienist visit could easily come to £400 to £800.

Look at tooth 16 again. The AI marked it as enamel-only with moderate confidence. That’s the one to ask about. “Could we try fluoride and recheck 16 in six months instead?” is a completely reasonable question, and a good dentist will either agree or tell you why not (perhaps they could feel a cavity with the probe, or the shadow has grown since your last x-ray). Tooth 26 is a different story: dentine involvement with high confidence is the sort of thing that usually does need treating.

The margin defect on 36 sits somewhere in between. Old fillings often show a small gap or step on x-rays and stay perfectly fine for years. Ask whether there’s decay under it or whether it just looks imperfect.

The questions to ask about each box

You don’t need clinical training for this. Pick any box and ask:

1. What is the software flagging here, and do you agree with it?
2. Is this in the enamel or has it reached the dentine?
3. Did you find anything when you examined the tooth itself?
4. What happens if we monitor it rather than treat it now?
5. Has this area changed since my previous x-rays?

The fifth question is often the most useful. One x-ray is a snapshot. Two taken a year apart tell you whether something is actually getting worse.

Getting your x-rays and report

Under UK GDPR you can ask for a copy of your dental records, x-rays included, and the practice should normally provide them free within one month. Some practices will also share the AI report, and a few now send it to patients automatically because it makes the treatment plan easier to follow. Ask for both. If you want a second opinion from another dentist, having the images saves you a second set of x-rays. Each one is a very small dose (a bitewing is roughly 0.005 mSv, less than a day of natural background radiation in the UK), but there’s still no reason to repeat them for nothing.

Where ChatGPT fits, and where it doesn’t

Don’t upload your x-ray to ChatGPT, Claude or Gemini and ask them to diagnose it. General chatbots aren’t trained or approved for that job, and they will happily describe things that aren’t there. What they’re good at is translating jargon and helping you work out what to ask.

Something like this works well:

My dentist's AI x-ray report says "Tooth 16 caries distal, enamel,
moderate confidence" and the plan is a composite filling at £140.
Explain in plain English what that means, whether enamel-only decay
is ever monitored instead of filled, and give me three questions to
ask my dentist. I'm in the UK.

Take your name, date of birth and NHS number out of anything you paste in. You’ll get a clear explanation and a short list of questions, which is exactly what you need going into a conversation where the other person has the clinical knowledge. For more on how practices are using these tools, including 3D scans and automated notes, we’ve put it all together in our guide to AI at the dentist.

When the boxes should make you look elsewhere

Most dentists use these tools well. Still, a few patterns deserve a second opinion. If every box on the screen has turned into a paid item on your plan, with no mention of monitoring anything, be wary. Be wary too if the dentist can’t tell you whether they examined each tooth themselves, or if you’re being pushed to decide on the day with a “today only” price. AI tends to flag more early changes than a human scanning by eye. That’s useful for catching problems, but it can also inflate a plan if nobody applies judgement to what it finds.

A dentist who’s comfortable with the technology will usually be glad you asked. Plenty of them turned the screen towards you precisely so you’d ask “what’s that red one?” and they could show you.