Dental radiography, commonly known as dental X-rays, allows dentists to examine hidden structures within the mouth. These images are produced by X-ray radiation passing through oral tissues, with varying absorption based on density. Teeth and bones appear lighter due to higher radiation absorption, while less dense areas like decay or infections appear darker. This diagnostic tool provides insights into areas not visible during a standard visual examination.
Purpose of Dental Radiographs
Dental X-rays detect issues not visible during a routine oral examination. They identify cavities, especially those developing between teeth or beneath existing fillings. Radiographs also reveal bone loss associated with gum disease, indicating the health of supporting structures around the teeth.
X-rays assist in diagnosing infections at the root of a tooth, such as abscesses. They pinpoint the position of unerupted or impacted teeth, like wisdom teeth, aiding in planning their removal or monitoring their development. In children, these images track the growth of adult teeth and determine if baby teeth need removal to prevent complications. Early detection allows for timely intervention, potentially preventing more extensive treatments.
Common Types of Dental Radiographs
Dental X-rays are categorized into two main types based on where the imaging sensor is placed: intraoral, meaning inside the mouth, and extraoral, meaning outside the mouth. Intraoral X-rays are the most frequently used and provide detailed images of individual teeth and their surrounding structures. Bitewing X-rays, a common intraoral type, capture images of the crowns of both upper and lower back teeth in a single view, primarily used to detect decay between teeth and assess bone levels due to gum disease.
Periapical X-rays show the entire tooth, from the crown to the root tip, including the surrounding bone, which helps in diagnosing issues like infections or abnormalities at the root. Occlusal X-rays, another intraoral type, reveal a full arch of teeth in either the upper or lower jaw, often used to track tooth development or locate salivary stones.
Extraoral X-rays capture a broader view of the jaw and skull, offering a comprehensive overview rather than detailed images of individual teeth. Panoramic X-rays are a widely used extraoral type, providing a single image of the entire mouth, including all teeth, both jaws, and the temporomandibular joints (TMJs). These are beneficial for assessing impacted wisdom teeth, planning for dental implants, or identifying jaw problems. Cone Beam Computed Tomography (CBCT) provides three-dimensional (3D) images of dental structures, soft tissues, nerves, and bone, used for complex cases like precise implant placement planning or orthodontic assessments.
The Radiography Process
The dental X-ray process is quick and causes no discomfort. Before imaging, the patient is covered with a lead apron and often a thyroid collar to minimize radiation exposure. A dental professional positions a small sensor or film holder inside the mouth, asking the patient to bite down gently to keep it in place.
For each image, the patient remains still for a few seconds while the X-ray machine captures it. Modern dental practices use digital sensors, displaying images almost instantly on a computer screen. This digital technology eliminates chemical processing, allowing the dentist to review images immediately during the appointment. The entire procedure, depending on the number of images needed, takes only a few minutes.
Radiation Safety and Frequency
Concerns about radiation exposure from dental X-rays are common, but modern technology has made these procedures safe. Digital dental X-rays, now widely used, emit significantly lower levels of radiation compared to older film-based X-rays, often 80% to 90% less. The radiation from a set of bitewing X-rays is minimal, comparable to background radiation from natural sources, such as a short airplane flight or a day outdoors.
To enhance safety, a lead apron is draped over the patient’s torso and a thyroid collar around the neck, shielding sensitive organs from scattered radiation. Dental professionals adhere to the “As Low As Reasonably Achievable” (ALARA) principle, ensuring X-rays are only taken when clinical benefit outweighs potential risks.
The frequency of dental X-rays is not uniform for all individuals; it is determined by a dentist based on several factors. These include the patient’s age, oral health status, presence of symptoms, and individual risk for developing dental diseases like cavities or gum disease. For new patients, a full set of initial X-rays may be recommended to establish a baseline, while follow-up bitewing X-rays might be taken every one to two years depending on risk.