X-rays, also called radiographs, are essential imaging studies capable of providing a tremendous amount of information in order to create a proper dental care treatment plan. Although dental x-rays are most used for diagnostic reasons, they can also be useful for preventive cases, helping both the patient and the dental professional to prevent major tooth complications (1, 2).
Dental x-rays can help dentists diagnose issues with the teeth and jaws, including:
· Tooth decay.
· Bone loss in the jaw.
· Changes in the bone or root canal.
· Condition and position of teeth to help prepare for dental procedures.
· Cysts and some types of tumors.
These x-rays are divided into two main categories: intraoral, the ones taken from inside the mouth, and extraoral, the ones taken from outside the mouth (1, 2).
What are intraoral x-rays?
These are the most common type of radiographs taken in dentistry, providing a high level of details regarding the teeth, bone structure, and supporting tissues of the mouth. There are different types of intraoral x-rays, showing diverse aspects of the teeth (2, 3):
Bite-wing x-rays. By taking one or two of these x-rays on each side of the patient´s mouth, dentists are able to highlight the crowns of the back teeth, specifically the upper and lower molars and the bicuspids. These x-rays are called like this because the patient needs to bite down on a wing-shaped device that holds the film in position while the imaging exam is taken.
Periapical x-rays. Similar to the bite-wing x-rays, periapical x-rays highlight the entire length of just one or two teeth at a time, from crown to the root where the tooth attaches into the jaw.
Occlusal x-rays. Normally used in children, these x-rays are capable of highlighting tooth development and placement by showing almost the entire arch of teeth in either the upper or lower jaw.
What are extraoral x-rays?
These radiographs are made by placing the film outside the mouth. Although these are less detailed than intraoral x-rays, these are considered to be x-rays that show a full picture of the mouth by providing information about the teeth, jaw, and skull. The most common extraoral x-rays used are (2, 3):
Panoramic x-rays. By including all the teeth on both jaws, these show the entire mouth on just one take. However, to perform panoramic x-rays, there is need for a special machine capable of capturing the full, broad view of the jaws in one film. To achieve a useful radiography, the patient needs to be positioned carefully with the head and jaw placed in a special position.
Tomograms. These show a particular layer or slice of the mouth, blurring out other areas. These are especially useful when there is need to examine a specific structure that normally can be difficult to clearly see due to the presence of other close structures.
Cephalometric projections. Being useful to determine the best type of orthodontic treatment or realignment approach for each patient, these x-rays show the entire side of the head. The position of the teeth in relation to the jaw and the patient´s profile is shown.
Sialograms. These special type of x-rays makes salivary glands to be seen on the image due to the use of a dye injected into the glands. Sialograms are prescribed to look for salivary gland issues, such as blockages or Sjogren´s syndrome.
Dental computed tomography (CT). A type of imaging test capable of showing internal structures in three dimensions (3-D) by collecting slices as the machine makes diverse revolutions around the patient´s head. It is usually done to find issues located in the bones like cysts, tumors, and fractures, or to determine size and placement location for implants.
Cone-beam computed tomography (CT). Similar to the standard CT scan but using a machine that rotates around the patient´s head, being capable of capturing all the information in just one rotation.
Digital imaging. One of the most modern x-ray techniques, it is capable of sending the resulting image to a computer where it can be viewed, stored or printed out in just seconds.
MRI imaging. A type of 2-D imaging method capable of taking a tridimensional view of the oral cavity, including jaw and teeth. This imaging test is ideal to view problems regarding soft tissues like the gums.
How often should dental x-rays be taken?
As many other clinical specialties, the use of x-rays depends on the medical and dental history and current condition of the patient. While there are individuals that need radiographies as often as every 6 months, there is also people that only need radiographies to be performed just a couple of times in their life. Usually, every new dental patient needs to have x-rays taken with the examination. Other individuals need imaging tests to be performed more often, including (2):
· Patients with a lot of restorative work.
· Individuals with high levels of sugar consumption.
· Patients with periodontal disease.
· Individuals suffering from dry mouth.
Are dental x-rays safe?
Nowadays, x-rays are very safe due to the new technology being used to manufacture the machines and the safety regulations that professionals need to follow. This allows the machines to emit very small amounts of radiation per shot and provide good quality information for each case.