Dental x-rays are classified as either intraoral or extraoral.
Intraoral x-rays requires the x-ray film to be positioned inside the patient’s mouth while in extraoral, the film is outside the mouth.
The most common intraoral x-rays include periapical, bitewing, and occlusal x-rays. Extraoral x-rays, on the other hand, are your panoramic and cephalometric x-rays.
As mentioned in the previous article (A Patient’s Guide to Dental X-rays), different conditions and procedures require different types of dental x-ray. Each type provides different views of the teeth and associated structures.
A periapical x-ray captures the image of a single tooth (or sometimes two) from the crown to its root/s and supporting bone.
It uses a small film that fits inside the patient’s mouth.
It is the most detailed of all the dental x-rays (intraoral or extraoral) and thus most often required in determining the extent of tooth decay.
It is also the one used in procedures such as extraction and more importantly, in root canal treatment.
A bitewing x-ray produces an image of both the upper and lower back teeth when in full contact with each, a.k.a. bite – hence the name.
It shows the crown of these teeth only and not the roots and supporting bone.
It is used to assess the extent of decay in-between teeth. The small film used for periapical x-ray is also the one used in this type of dental x-ray.
When taking bitewing x-ray, a small tab is used to position the film beside the involved teeth.
An occlusal x-ray shows the whole dental arch viewed from the biting (occlusal) surface of the teeth.
It is done to see how the upper and lower teeth line up when in contact with each other.
It may also show abnormalities in the palate or roof of the mouth. The film used is slightly bigger than the ones used in periapical and bitewing x-rays.
A panoramic x-ray captures the upper and lower teeth – all 32 of them, including the wisdom teeth – in one film.
It shows the jaws (both upper and lower) and other surrounding structures as well.
This type of x-ray is shot by a machine that revolves around the head. This type of dental x-ray is used to identify the presence of impacted wisdom teeth or to plan an orthodontic treatment.
It may also be a useful aid in diagnosing advanced cases of periodontal disease, investigating jaw problems, or determining the feasibility of an implant surgery.
A panoramic x-ray is otherwise known as orthopantomogram.
A cephalometric x-ray is the primary type of x-ray required from patients who wish to undergo orthodontic treatment, along with panoramic x-ray.
It is taken from the side of the head, and thus enables the orthodontist to evaluate the patient’s profile and predict how the treatment may affect the teeth and the surrounding bone.
It helps determine what course of treatment is most applicable to the patient’s case. This type of x-ray is sometimes ordered by an otorhinolaryngologist as well because it can show a good view of the airways. An otorhinolaryngologist is medical doctor who specializes in the conditions of the ears, nose, and throat.