Dental X-ray names and what each one shows
Dental X-rays fall into two groups. Intraoral X-rays are taken with a small sensor or film held inside the mouth and show a few teeth in fine detail. Extraoral X-rays are taken with the sensor outside the mouth and show the larger structures, such as the jaws and joints. No single X-ray does everything, which is why a dentist may take different ones for different questions.
| X-ray | What it shows | Typically used for |
|---|---|---|
| Bitewing | The crowns of upper and lower back teeth together, and the top of the bone between them | Spotting decay between teeth and checking old fillings |
| Periapical | One or two whole teeth from crown to root tip and the bone around the root | Toothache, infection at the root, root canal work |
| Occlusal | A wider view of the floor or roof of the mouth and the bite | Extra teeth, stones in a salivary duct, jaw swellings, children's teeth |
| OPG (panoramic) | Both jaws, all teeth, sinuses and jaw joints on one flat image | Wisdom teeth, impacted teeth, a first overview before treatment |
| CBCT | A three-dimensional scan of a chosen area | Implant planning, buried teeth, complex root canals, jaw problems |
Common types of dental X-ray: general information, not a recommendation for any individual.
Intraoral X-rays: bitewing and periapical
A bitewing X-ray is taken while you bite gently on a small tab. It shows the crowns of both jaws together, which is where the early decay between neighbouring teeth hides. A periapical shows the same tooth from crown to root tip, so it is the one used when a tooth hurts or after a root canal to check healing.
Both can be taken on a digital sensor, which gives the image on a screen straight away. Our guide to the RVG dental X-ray explains how that works. An occlusal is a larger film or sensor, held between the teeth, for a wider area than a periapical covers.
Extraoral X-rays: OPG and CBCT
An OPG dental X-ray (orthopantomogram) takes a panoramic picture of the whole mouth as the machine turns once around the head. It is the usual first picture for wisdom teeth and for checking how the jaws and teeth lie. It is less sharp in detail than a small intraoral X-ray.
CBCT, or cone beam CT, builds a 3D image, so a dentist can see the width and height of the bone, the position of nerves and the shape of root canals. It involves more radiation than a small X-ray, so it is kept for cases where the extra detail will change the plan. How decay looks on these pictures is explained in our guide to dental cavities on X-ray.
Are dental X-rays safe, and what about pregnancy?
Dental X-rays use a small amount of radiation, and a dentist asks for one only when it is likely to change the diagnosis or treatment. A lead apron or collar and a narrow beam are standard precautions. Digital sensors need less radiation than old film.
Always tell the dentist if you are or might be pregnant. Routine X-rays are usually put off until after the baby arrives, and an urgent one is taken only when it is clearly needed and with protection. Our guide to dental treatment during pregnancy covers what else changes. Ask the dentist what the X-ray is for before it is taken. The answer should be a specific question about your teeth.
If a tooth is causing pain, swelling of the face, fever, or trouble swallowing or breathing, do not wait for a routine appointment. That means same-day care, and a hospital emergency if breathing or swallowing is affected.
Common questions
Which dental X-ray is best for a toothache?
A periapical X-ray is usually the one used, because it shows the entire tooth from crown to root tip and the bone around it. The dentist may add a bitewing to look for decay between teeth.
How often are dental X-rays needed?
It depends on your risk of decay and gum disease, your age and what treatment is planned. There is no fixed schedule for everyone, so ask the dentist why a new X-ray is needed.
Is an OPG the same as a CBCT?
No. An OPG is a flat, two-dimensional picture of the whole mouth. CBCT is a three-dimensional scan, usually of a smaller area, and it shows depth and position that a flat picture cannot.
Can a dentist diagnose everything from an X-ray?
No. An X-ray shows hard structures well and soft tissue poorly. The dentist combines it with an examination and your history, so a normal X-ray does not rule out a problem and a shadow on it does not always mean disease.
About this page
This page is general information, not a diagnosis or a quotation. Prices are prevailing Lucknow market ranges. Your own treatment and cost are determined after an examination. For questions about your own case, call +91 83036 12717.