Why Your Dentist Takes X-Rays Before Finalising Your Plan

You’ve had the check-up and now you have a treatment plan in your hand: two fillings, maybe a crown, perhaps a line that says “periodontal therapy” with a number next to it. If your dentist took X-rays before writing it, that’s a good sign. Most of what drives a treatment plan sits where nobody can see it by looking in your mouth, including your dentist.

If the plan was written without recent X-rays, don’t jump to suspicion. Ask about it. There are usually good reasons, but you should know what they are before you pay.

What the mirror misses

A dentist looking in your mouth sees the biting surfaces, the fronts and backs of your teeth, and your gums from the outside. Three things stay hidden.

Decay between teeth. Where two back teeth touch, the contact point is a tight spot that a probe can’t reach and a mirror can’t see. Decay often starts just below that contact. By the time it’s visible as a grey shadow through the enamel, it has usually reached the softer dentine underneath, and a small filling may have become a large one.

Bone loss. Gum disease (periodontitis) slowly destroys the bone that holds teeth in their sockets. The gum can look fairly normal while the bone underneath has dropped by several millimetres. Pocket measurements with a probe give part of the picture. An X-ray shows how much bone is actually left.

Problems at the root tip. An infection at the end of a root can sit there quietly for months. A periapical X-ray shows it as a dark patch around the tip. Without that image, a tooth might get a crown when what it needed first was root canal treatment, or an extraction.

This matters for your wallet because each hidden finding changes what goes on the plan, and often what it costs.

The X-rays you’re most likely to have

On the NHS in England, X-rays are included within your band charge. If they’re clinically needed as part of a check-up, they come under Band 1, which was £27.80 in 2025/26. You don’t pay extra per film. Wales, Scotland and Northern Ireland charge differently, but the X-rays still sit inside the course of treatment.

Note one thing in that table. A panoramic X-ray is good for the big picture, but it’s noticeably worse than bitewings at picking up small cavities between teeth. If your only image is an OPG from two years ago, your dentist may still want bitewings before committing to a filling plan.

How often is “recent”?

UK dentists follow guidance from the College of General Dentistry (formerly the FGDP) on how often to take X-rays. Under the Ionising Radiation (Medical Exposure) Regulations 2017, every exposure has to be justified, so the decision depends on your risk rather than a fixed calendar. For adults, the guidance roughly works out as:

• High decay risk: bitewings every 6 months
• Moderate risk: every 12 months
• Low risk: every 24 months

If you’ve had three new fillings in the last year, you’re high risk and a plan based on 18-month-old bitewings is out of date. If you haven’t needed a filling in a decade, X-rays from last year are probably fine.

Radiation worries put some people off. A pair of digital bitewings delivers roughly 0.01 mSv. The average person in the UK gets about 2.7 mSv a year from natural background radiation, so two bitewings come to about a day and a half of ordinary life in Britain. A return flight to Spain gives you more.

Worked example: two quotes, one mouth

Priya, 41, moved house and registered with a new private practice. She had two quotes within a month.

Practice A did a visual exam only and wrote:

Upper left 6 – composite filling (occlusal)         £120
Scale and polish                                    £65
Total                                               £185

Practice B took two bitewings (£50 for the pair) and wrote:

Bitewing radiographs x2                             £50
Upper left 6 – composite filling (occlusal)         £120
Upper left 5 – composite filling (distal, between   £150
  teeth, radiographic finding)
Lower right 7 – composite filling (mesial,          £150
  radiographic finding)
Periodontal assessment + root surface debridement,  £280
  lower front (bone loss on radiograph)
Total                                               £750

At first glance Practice B looks like it’s upselling, at four times the price. But every extra line is labelled “radiographic finding”. The two hidden cavities were between teeth, exactly where Practice A couldn’t look. The bone loss under the lower front teeth would have kept going quietly.

Priya didn’t need to trust either practice blindly. She asked Practice B for copies of the X-rays and went back to Practice A with them. Practice A agreed with both cavities. Practice A’s quote wasn’t dishonest. It was incomplete, and it would have turned into a £600 bill sooner or later anyway.

What to ask if your plan had no X-rays

Ask these politely. A good dentist will answer them easily.

1. “When were my last X-rays taken, and which type?”
2. “Do you need new ones before you can be confident in this plan?”
3. “If not, why not? Is it because of my risk level or because I had them elsewhere recently?”
4. “Could anything on X-rays change this quote?”

Sometimes there’s a perfectly good reason. You might be pregnant and the dentist is deferring non-urgent X-rays. You might have had bitewings at your previous practice eight months ago and your dentist has requested them. Some plans are simply a quick fix for a chipped front tooth that doesn’t need imaging.

If the plan includes a crown, a root canal, an implant or an extraction and no X-ray was taken, though, ask firmly. Those treatments shouldn’t go ahead without one.

You’re also entitled to copies of your X-rays. Under UK GDPR, a subject access request to the practice is normally free and must be answered within one month. Most practices will simply email the images if you ask at reception.

Using ChatGPT or Claude to check the plan

AI tools are good at turning dental jargon into plain English, and at helping you work out what to ask. They aren’t good at reading X-ray images. Don’t upload your radiographs to ChatGPT, Claude, Gemini or Copilot and treat the answer as a diagnosis. Specialist software such as Pearl or Overjet is built for that job and used by clinicians, but general chatbots are not, and they will sometimes describe a cavity that isn’t there with total confidence.

What works is pasting in the text of your plan. Remove your name, date of birth and NHS number first. A prompt like this gets useful results:

I'm a UK patient with no dental training. Below is my private treatment
plan. For each line:
1. Explain what the treatment is in plain English.
2. Tell me whether it would normally need an X-ray to diagnose.
3. Flag any line where the price looks unusual for a UK private practice
   outside London.
Then give me 5 questions to ask my dentist before I agree.

[paste plan here]

Run that on Practice B’s quote and a decent model will explain that “distal” means the back surface of the tooth, touching its neighbour. It will tell you that decay there is classically found on bitewings, and that £150 is within the normal range for a two-surface composite. It should also point out that “root surface debridement” is deep cleaning below the gumline and usually needs X-rays plus pocket charting to justify it.

Follow up with something narrower: “My plan has no X-ray listed but includes a crown on the lower left 6 at £850. What should I ask?” The answer should steer you towards asking whether a periapical X-ray was taken to check the root and bone before the crown is fitted.

If you want to understand every line on the plan, including terms like “MOD”, “RCT” and “Band 3”, our guide to treatment plans explained walks through it item by item.

When it’s worth getting a second opinion

Your dentist has refused to take X-rays but wants to start on crowns or bridgework. You asked for copies and got vague answers. The plan quotes for “multiple fillings” with no tooth numbers or surfaces listed. Any one of these is enough to see someone else before you hand over a deposit.

Take the X-ray copies with you, because a second dentist with good images can often give a view in a standard examination appointment, typically £40–£70 privately, without exposing you to new radiation. Practice B’s £50 bitewings did more for Priya than the whole of Practice A’s appointment. For a few minutes in the chair and a day and a half of background radiation, that’s a cheap way to find out what you’re really paying for.