These are used in dentistry for many reasons.  First and foremost is the detection of decay in areas which are not visible.  Diagnosis of abcesses and infection, and detection of periodontal and gingival health.   Also, the health of bone and analysis during treatment procedures are often monitored with x-rays.  The amount of radiation absorbed by dental x-rays is minimal.  Because of the advances in the technology of dental x-rays, radiation has been reduced by as much as 90% from years ago.