X-rays are an integral part of oral exams because they help detect any problems not visible during an external examination. They can show how deep a cavity penetrates, if the root of a tooth is infected, and whether there is any bone loss. Not all people need x-rays during every oral exam. Dental history, general oral health and age all determine the frequency. Children typically need x-rays often, since their mouths and teeth change so rapidly.
Although x-rays use radiation, their occasional use is not dangerous, and the valuable information they provide helps the doctor address the source of your main concerns.