Dental radiographs pose potential hazard to human health, study finds
BRIGHTON, UK/ATLANTA, US: The incidence of thyroid cancer and meningioma is increasing globally. New research has found that repeated exposure to dental radiographs may increase the risk of thyroid cancer and tumours in the tissue covering the brain and spinal cord. The researchers concluded that dental radiographs should, therefore, be prescribed only when the patient has a specific clinical need and not as a standard part of routine dental evaluation. Additionally, dental professionals should maintain dental radiographic records in order to avoid unnecessary screenings.
About 3,500 new cases of thyroid cancer and 1,850 meningiomas are diagnosed each year in the UK, and researchers have discovered an increase in both diseases in numerous countries in the past 30 years. Just this year alone, the American Cancer Society has reported over 52,000 new cases of thyroid cancer, and meningiomas account for approximately one out of every three key brain and spinal cord tumours in the US.
Prof. Anjum Memon, Chair in Epidemiology and Public Health Medicine at Brighton and Sussex Medical School, believes that some of the factors that contribute to the increase in thyroid cancers are increased surveillance and dental screening, and over-diagnosis. In the systematic review and meta-analysis, Memon and his team summarised the findings of previously published studies on dental radiographic exposure and the risk of thyroid cancer, meningioma and other cancers of the head and neck.
“Little is known about the impact and magnitude of risk associated with dental X-rays, which have been the fastest-growing source of human exposure to low-dose ionizing radiation during the past three decades—with many patients being exposed to dental X-rays on multiple occasions over many years. Given this high lifetime prevalence and frequency of exposure, even a small associated increase in cancer risk would be of considerable public health importance,” he noted.
Referring to the fact that the thyroid gland is located in the neck and the meninges cover the brain and spinal cord, Memon said: “These organs will be exposed to radiation from dental X-rays. Both organs are highly radiosensitive, particularly in childhood and adolescence. Dental radiography, a source of low-dose diagnostic radiation, is often overlooked as a potential hazard to these organs.” However, he added that more research was needed to further test the hypothesis.
According to Memon, current UK, European and US guidelines have already stressed the need for thyroid shielding during dental radiography.
The study, titled “Dental X-rays and the risk of thyroid cancer and meningioma: A systematic review and meta-analysis of current epidemiological evidence”, was published online on 14 October 2019 in Thyroid, ahead of inclusion in an issue.