The results of a study were reported online Tuesday, in the American Cancer Society’s journal, Cancer, linking dental x-rays with an increased risk of a common brain tumor in adults.
The study was led by Dr. Elizabeth B. Claus, a professor at the Yale School of Public Health in New Haven, CT, and a neurosurgeon at Brigham and Women’s Hospital in Boston. The findings suggest that dental “bite wing” x-rays are linked to meningiomas. These meningiomas are tumors, which arise in the meninges, the membrane surrounding the brain and spinal cord, and they account for approximately one third of detected brain tumors in the U.S. Most of the meningiomas are benign, slow-growing tumors, but they exert pressure on the brain, causing debilitation. Dr. William Curry, a neurosurgeon at Massachusetts General Hospital, said that although meningiomas are only cancerous in 1-2 percent of cases, even the benign tumors could cause significant impairment and become difficult to remove.
X-rays, which expose a small piece of film placed between the teeth to a beam of radiation, raised the risk of meningiomas 1.4 to 1.9 times, Claus and her colleagues found.
The study also found an association between the less-commonly used panorex x-rays, which are taken outside the mouth, around the entire head, providing a panoramic view of the full set of top and bottom teeth, and meningioma. Panorex x-rays are often used to assess the need for braces. This x-ray increased the risk of developing a meningioma, if performed before age 10, by almost five times.
The study reports that ionizing radiation is the major environmental risk factor for meningioma, and that dental x-rays are the most common source of ionizing radiation among U.S. residents.
Dr. Claus noted that the risk factors for meningioma, the most commonly diagnosed brain tumor, remain poorly understood, partly due to the fact that meningioma was only added to brain tumor registries in the United States in 2004. She indicated that it generally takes about 20 to 30 years after radiation exposure for the meningioma to develop.
The meningioma can grow larger than a baseball. The pressure on the brain and spinal cord can cause headaches, vision problems, and impairment and/or loss of speech and motor control.
Although this study is very alarming and should not be taken lightly, Dr. Keith L. Black, neurosurgeon at Cedars-Sinai Medical Center in Los Angeles, states that the risk of meningioma is only 3 cases for every 100,000 people.
Patients can refuse dental x-rays if they are not experiencing any problems. With this new study going public, most dentists should understand patients’ justified fear of x-rays. The American Dental Association recommends that healthy children have x-rays about every one to two years, and healthy adults, every two to three years. The study did acknowledge that some of the patients had received dental x-rays decades ago, when radiation exposure was greater.
Today, we have the advantage of improved technology and modern x-ray equipment. However, I would definitely think twice if I saw an old-fashioned x-ray machine in a dentist’s office, before having an x-ray performed!