Why images are needed when the mouth looks fine

Decay between two teeth starts where they touch, where you cannot see it, feel it, or reach it with a mirror. It shows itself only after passing through enamel into the softer dentin, where it spreads faster and the repair gets bigger. The same goes for everything under the gum: bone loss, an abscess sitting for months without symptoms, cysts, impacted wisdom teeth.

One image is a snapshot. A series taken over years shows direction, and direction tells us whether a shadow between two teeth is stable enough to watch or moving fast enough to treat. That is why we ask a former office for your old images.

Bitewings, periapicals and panoramic images: what each one shows

Bitewing
You bite on a tab and the image captures the crowns of the upper and lower back teeth together. The workhorse. Shows decay between teeth, decay under fillings, and the height of the bone crest. Not root tips.
Periapical
One tooth, crown to past the end of the root. The image for a tooth that hurts, one being assessed for root canal therapy, a suspected abscess, or a site planned for a dental implant.
Full mouth series
Bitewings and periapicals covering every tooth and the bone around it. Taken for a new patient with a complicated history or a mouth not imaged in years, then rarely repeated.
Panoramic
One wide image of both jaws, sinuses and jaw joints, taken with the machine rotating around your head. Good for wisdom teeth, cysts, fractures and the shape of the jaws. Poor at fine detail, so not a replacement for bitewings.

How much radiation is in a dental x-ray

You are exposed to radiation constantly, from soil and granite underfoot, from radon, from cosmic rays, and from ordinary food. There is more at elevation than at sea level, and flying raises it again.

A digital dental x-ray is small in that context. A set of bitewings sits in the same range as the background dose you take on in an ordinary day, and less than a flight across the country. The sensor needs less exposure than film did, and the beam is collimated to a small rectangle. That does not make the dose nothing. We work to ALARA, as low as reasonably achievable: image only for a diagnostic reason, with the fewest images and the lowest exposure that answer it.

Shielding, pregnancy and keeping exposure down

The lead apron and thyroid collar
Standard for decades, though national guidance has moved away from routine shielding: the beam is collimated tightly enough to stay on the area imaged, and a collar out of place blocks what we need to see, meaning a retake and double the exposure. Tell us your preference before we start.
If you are pregnant, or think you might be
Say so before any image is taken. Routine screening can usually wait. Where something needs diagnosing, dental imaging is generally considered acceptable in pregnancy, and an undiagnosed infection carries risks of its own. Decided at the appointment.
Children
More sensitive to radiation than adults, so images are taken less often and with settings adjusted for size. Their bitewings are mostly about watching the contacts between the back teeth, where their cavities form.

Dental x-ray questions

Can I refuse x-rays?

You can decline anything. Be clear what it means, though. Without images we are examining part of each tooth and none of the bone, and a diagnosis on that basis is incomplete. If the reason is cost or radiation, say so.

Why do I need new x-rays when I had some two years ago?

An x-ray is a photograph of a moment. Decay progresses and bone levels change, and much of the value is in the comparison. If your previous ones are recent enough we will use them, so ask your former office to send them.

Do digital x-rays really use less radiation than film?

Yes. The sensor is more sensitive than film emulsion, so it needs less exposure to produce a readable image, and there is no exposure wasted on a film that developed badly.

The sensor makes me gag. What can be done?

Quite a lot, so say so before we start. Positioning can be changed, the sensor cushioned, and breathing through the nose helps most people. Fighting through it usually produces a bad image that has to be repeated.

What happens if you find something?

We put the image on screen and point at it, then tell you what it is, how urgent it is, and what happens if it is left alone. Some findings get watched rather than treated. If it hurts now, that is a dental emergency.