There are two types of x-rays commonly used by the general dentist. These are intra-oral x-rays and panoramic x-rays. Intra-oral x-rays are the small x-rays placed inside the mouth. They are used to detect decay, evaluate bone levels around the teeth, detect cysts or tumors associated with the teeth and jawbone, identify defective restorations or crowns and evaluate root shapes.
Intra-oral x-rays may be referred to as bite-wings or periapicals. Bite-wing x-rays show the crowns of several upper and lower teeth in one view. This allows us to look for decay between the teeth in only two or four x-rays. Bite wing x-rays are recommended once a year for most people. Periapical x-rays show the crown and roots of several upper or lower teeth. These are used to evaluate the presence of cysts that may form at the root tip, determine root shape prior to extracting a tooth, identify root fractures in trauma cases, etc.
Periapical x-rays are usually taken during dental emergencies to evaluate one or more teeth. They are also taken in conjunction with bite wing x-rays when a full mouth series of x-rays is indicated. Full mouth series of x-rays are usually recommended at least every three years in conjunction with panoramic x-rays.
Panoramic x-rays show the entire upper and lower jaw and jaw joints, the maxillary sinuses, nasal septum, nasal passages and other facial bony structures. These x-rays are not used to diagnose decay and other problems that intra-oral x-rays are used for. Panoramic x-rays are used to evaluate third molars for their removal, jaw or facial bone fractures, cysts, tumors or other pathology, jaw joints for trauma or disease, etc. These are recommended every three years for most people in conjunction with full mouth x-rays.