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Portable intraoral X-ray devices are marketed as an alternative for conventional wall mounted devices. On the basis of a recent clinical trial the diagnostic quality of portables appears to measure up to the conventional devices. When CE-certified portable devices are used with rectangular collimation and a backshatter radiation shield with adapted technique resulting in a beam parallel to the ground, operator exposure stays well within dose limits. However, the dose to the operator is higher than when using conventional devices. Therefore, in the Netherlands, guidelines restrict the use of portable devices to ambulant use outside the dental clinic while deploying additional radiation protection measures. If presumed advantages of increased control over the exposure due to proximity to the patient would be substantiated by research, this restricted use could be reconsidered. Dentists should be aware of online availability of non-CE-certified portable intra-oral X-ray devices that are potentially unsafe.

During intraoral radiography of the upper anterior teeth, the dose the patient is exposed to can be reduced by shielding the thyroid area by using a thyroid shield or collar. However, the dose to the patient is already low and it is questionable whether efforts to reduce this even further are sensible. A cost-utility analysis demonstrated that thyroid shielding is utile when it is used at least 24 times per year for upper anterior exposures in children.

Soon after the discovery of X-rays, it became clear that their use can cause detrimental effects. The field of radiobiology deals with these detrimental effects. In this article, the theoretical concepts of radiobiology relevant to diagnostic X-ray use are presented. The effects of radiation on living tissues, the relationship between dose and effect, and a translation of these effects into the dental application are discussed. X-rays cannot be considered to be harmless even when used at the relatively low doses as in dentistry. If applied with justification and optimization, the risk to the patient will, however, be small.