A pair of bitewing X-rays, the small films used to check between a child's back teeth, gives roughly the same radiation as a day or so of ordinary life in Australia, where we all absorb natural background radiation from the ground, air and food. That dose is very small. Children are still more sensitive to radiation than adults, though, so the useful question for parents is less "is it safe?" and more "does my child need this particular X-ray right now?"
Dentists work to that same question. An X-ray for a child should be taken only when the answer is likely to change their care, and then with the lowest dose that will do the job.
What a dentist cannot see without one
Looking in the mouth shows a lot, but not everything. The surfaces where two back teeth touch are hidden from view, and decay there can grow for a long time before a dark spot appears on top. By then it may be close to the nerve. A bitewing picks up those hidden areas while they are small enough for a minor filling, or even for fluoride and better cleaning to stop them.
X-rays also show what is happening below the gum: whether adult teeth are forming and in the right position, whether there is an extra tooth or a missing one, how the roots of a baby tooth are dissolving, and whether an infection has spread from a decayed or injured tooth. Our guide to when adult teeth come through explains why that timing matters.
The three types children are most likely to have
Bitewings are small images of the back teeth, taken mainly to look for decay between them. A periapical X-ray shows one or two whole teeth from the crown to the tip of the root, and is often used after a knock to a front tooth or when a tooth is painful. Both deliver very low doses.
An OPG, or panoramic X-ray, is taken by a machine that moves around the head and captures all the teeth and jaws in one image. It is useful for checking the development of adult teeth and for orthodontic planning, and the dose is still low, though a little higher than a pair of bitewings.
A 3D scan, called cone beam CT, delivers more radiation than these flat images. For children it is kept for specific questions a 2D picture cannot answer, such as exactly where an impacted canine sits next to the roots of other teeth.
Frequency follows risk, not the calendar
There is no rule that a child needs X-rays every six or twelve months. A child with no decay, good brushing and few sugary snacks may go one to two years between bitewings, and a low-risk teenager can often go longer. A child who has had several cavities, or whose back teeth are tightly packed together, may need them more often, because new decay is more likely and can progress quickly in baby teeth.
There is also no minimum age. Very young children rarely need X-rays unless there has been an injury or a problem is suspected. Bitewings usually become more useful once the back baby teeth are touching each other, which often happens in the preschool or early school years.
When braces are planned or under way, an OPG may be taken at the start and occasionally during treatment to check the roots and the position of unerupted teeth. Our article on what to expect with braces covers that stage.
How the dose is kept down
Digital sensors generally need less radiation than older types of film, and the image appears straight away, so retakes are less likely. The beam is narrowed to cover only the area being examined. Exposure settings are reduced for a child's smaller size. And the person taking the image is trained and licensed under state radiation safety laws.
Lead aprons are a common question. Recent guidance, including a 2023 position statement from the American Academy of Oral and Maxillofacial Radiology and a 2024 American Dental Association update, has concluded that lead aprons and thyroid collars are not needed for dental X-rays, because the dose they would block is negligible and the shielding can get in the way of the image, leading to a repeat. If you would like to know what we use, just ask on the day.
When parents would rather skip it
It is reasonable to ask why an X-ray is being recommended and what would happen without it. You are entitled to an answer you understand. The trade-off to weigh is that decay between teeth is often painless until it is advanced, and treating a large cavity or an infected baby tooth is usually harder on a child than a few seconds of biting on a sensor. Strong prevention at home, including the right amount of fluoride toothpaste, lowers your child's risk and, in turn, how often X-rays are needed.
For a broader look at X-rays for all ages, see our article on how often dental X-rays are needed. If your child has not had a check-up yet, our guide to a first dental visit explains what happens.
Child-friendly check-ups
Our dentists and oral health therapists see children of all ages and explain any X-ray before it is taken, so your child knows what to expect. You can find out more about our family dentistry, or see options for new families on our current offers page, and book with the team at Melrose Park.
