Submerging deciduous teeth and the value of x-rays

In dentistry and medicine we try hard to reduce the amount of x-ray radiation we use, it is a basic rule of radiation protection. This means we should only use x-rays when we really need to, when it could potentially alter our treatment. I take less radiographs now than I did when I qualified as an orthodontist. The standard I was taught as a dental student for orthodontic assessment was a panoramic (to show all the teeth) and an upper anterior occlusal (to check for supernumerary teeth and midline problems). As panoramic quality has improved the occlusal view is rarely needed, and I only take cephalographs in more severe cases now.

Sometimes there's a risk of not taking radiographs when we really need to, and there seems to be a real reluctance from some dentists to take radiographs on children, when they can help to manage a case.

The picture above is from an 11 year old boy I saw yesterday. His second deciduous molars are still present and are submerging quite significantly, being now below the contact points of the molar teeth and almost at gingival level. Having looked in the mouth I was certain that the premolar teeth must be missing, as is often seen when the deciduous molars submerge. A radiograph was indicated to confirm this before I decided on treatment.

Have a look at the radiograph and you can see that they are in fact all present and relatively well positioned. I have to admit to being rather surprised, but it does demonstrate that radiographs can be useful tools when correctly used.

Has it changed my management of the case? In the short term, no, as teeth submerged this far are best extracted anyway. But it does change my follow up of the case and the long term management (it also makes the IOTN 5s, so what appears to be a mild case now has a high need for treatment). I will need to make sure the space is maintained until the premolars erupt, I don't anticiapte any problems with this but I will review the patient regularly until the premolars erupt. If the premolars had been absent I'd have been more likely to allow some natural space closure before orthodontics (his anterior teeth are mildly crowded).

If you are a GDP please remember to monitor for submerging deciduous teeth, in this case the patient had been referred for another reason. If you are registered on Dentinal Tubules have a look at this thread which shows more severe sequalae for untreated submergence.

Should you be concerned about radiation from dental xrays?

With Japan and the Fukushima nuclear crisis in the news the dangers of ionising radiation have been brought to everyone's attention. You can't see radiation but most people are aware that it can be dangerous.

Radiation has several effects on the body. A large single dose (like being very close to a damaged reactor) has immediate effects that will make you ill or kill you, remember Alexander Litvinenko who was deliberately poisoned a few years ago.

For the general population it is the long term effects of an accumulated dose over many years that is more relevant, by either increasing the risk of cancer or causing birth defects, and these are the sort of effects that are seen in people living near Chernobyl where there was a nuclear disaster in 1986. Health problems are still being suffered by local residents and especially children due to the ongoing increased levels of radiation.

So how does dentistry fit into this? You might be concerned that having a dental xray will increase your radiation dose. Of course it does, but it needs to be put into perspective. You receive radiation every day from your surroundings (background radiation) and this is by far the biggest source of radiation most people receive over their lifetimes. A dental xray is roughly equivalent to the amount of background radiation you experience over the course of a day, and less than the additional amount you would get from a plane flight to Spain. Have a closer look at the clever chart above by clicking this link and you will see how insignificant the dose from a dental xray is compared to other radiation sources, including the radiation from Fukushima.

Of course that doesn't mean we don't have to be careful with medical and dental xrays. Modern technology has dramatically reduced the necessary dose to get a good xray picture and there are regulations which we, as dentists, must adhere to, as well as making sure we don't take any unnecessary xrays (for example if someone has had a recent xray elsewhere I always request a copy rather than taking a new one).

Dental xrays are an important tool for diagnosing problems and planning treatment, but they really aren't a significant problem when you consider overall radiation doses from all sources. My thoughts are with those who work or live near Fukushima and I sincerely hope the crisis can be controlled. Like Chernobyl, we may not be able to count the total human cost of the disaster for many years to come.