Different Types of Dental X-Rays and Uses

Dental x-rays are of two broad types, Intraoral and Extraoral. Intraoral x-rays are further categorized into three types as bitewing, periapical and occlusal. All three have specific uses in diagnosis.

Extraoral x-rays include CT, Panoramic radiographs, CBCT, and Cephalometric graphs. Extraoral radiographs give a broader perspective of your jaws and teeth. These are essential for orthodontic treatment and orthognathic surgery.


X-rays and dental treatments go hand in hand. It helps in proper diagnosis of any oral or dental condition. Without the correct diagnosis, your dentist can’t possibly know what to treat.

A significant part of your teeth is inside your jaws. X-rays penetrate your soft tissues and reveal the condition of the underlying bone and teeth.

X-rays assist in a wide range of diagnoses. They include diagnosis of decayed teeth, diagnosis of bone cancer and other bony malformation of jaws. They help dentists identify the position of an impacted wisdom tooth too.

There are also some less frequently used radiographs like sialograms and digital x-rays. Let’s review different tpes of x-rays and their uses in detail.

What are X-rays?

X-ray was discovered by Roentgen originally. These rays are a form of radiation which has many unique properties and one such property is tissue penetration. However, x-rays cannot penetrate calcified tissues which make them useful in the dental or medical field.

When a doctor projects an x-ray on any of your body parts, it casts an image of your internal bony structure on a photographic plate. Your tissues or body part should lie in between the x-rays and the photographic plate.

Ever since then their discovery, x-rays have carved a niche for themselves in medical diagnostics. Whenever you visit a dentist for whatsoever issue, he/she will suggest an x-ray first. In short, x-rays have an immense range of application in dentistry. (1)

Uses of X-rays in dental diagnostics

The following are some primary use of X-rays –

  • Reveal the depth of a cavity in your tooth.
  • Identify any cracks in the tooth.
  • Project issues related to the root, like an abscess or cyst.
  • Reveal bone cancer in the jaws and any malformation in your sinuses.
  • Find any bony or tooth related abnormality.
  • Reveal the position of an impacted wisdom teeth.
  • Help you judge the extent of fractures.
  • Help in the placement of implants, wires, and plates in your jaws.
  • Give an idea about bone density and extent of bone loss.
  • Helpful in the postoperative prognosis of any treatment.

Types of dental X-Rays

X-rays are an essential aid in dental diagnosis. There are two different types of dental X-rays and they are intraoral and extraoral X-Rays. These x-rays have different purposes in dentistry.

Intraoral X-rays

Dentists take these x-rays inside your mouth. They are further divided into three types –

  • IOPA or Intraoral Periapical X-ray
  • Bitewing Radiographs
  • Occlusal View Radiographs

Extraoral X-rays

These are shot outside your mouth and have a broader perspective. They are divided into four different types –

  • OPG or Ortho Pantomo Gram
  • CBCT or Cone Beam Computed Tomography
  • CT or Computed Tomography
  • Cephalometric projections

Intraoral X-Rays

Intraoral x-rays help with single tooth related diagnoses. The three different forms of intraoral x-rays have different applications –

Bitewing x-rays

Bitewing x-rays show details of the upper and lower teeth in isolated areas of your mouth. Each bitewing shows a tooth from its crown part to the level of its underlying bone. (2)


  • Bitewing x-rays detect decay between two teeth.
  • Also, bitewing x-rays show loss of bone caused by gum disease.
  • Bitewing x-rays can also help to determine the proper fit of an artificial crown.
  • It can also see any damage or breakdown in dental fillings.

Periapical X-Rays

Dentists refer to them as IOPA or intraoral periapical x-rays. They show the entire tooth from the crown, beyond the root.


  • Each periapical x-ray shows all the teeth in one specific region of either the upper or the lower jaw.
  • Periapical x-rays detect any changes in the root and surrounding bone structures.

Occlusal X-Rays

The occlusal radiographs track the development and placement of an entire arch of teeth in either the upper or lower jaw. They have a wider area of diagnosis.


  • These locate specific bony lesions like jaw cysts and granulomas.

Extraoral X-Rays

As the name suggests, dentists take these outside your mouth. These are most commonly in use for orthognathic surgeries and orthodontic teeth realignment procedures.

Panoramic X-Rays

Dentists refer to these as OPG or Ortho pantomo gram. They show the entire mouth area, all the teeth in both the upper and lower jaws on a single x-ray.


  • This x-ray detects the position of fully emerged as well as developing teeth, can see impacted teeth, and help diagnosis tumors.
  • An x-ray detects any sizeable bony lesion involving two or more teeth.

CT or Computed Tomography

It is a type of imaging that looks at interior structures in 3-D (three dimensions). It gives an entire 360 degrees view of your entire skull and provides a detailed picture.


  • This type of imaging reveals problems in the bones of the face such as cysts, tumors, and fractures.

CBCT or Cone Beam Computed Tomography

CBCT is a modern-day imaging technique in dentistry. This type of x-ray creates 3-D images of dental structures, soft tissue, nerves, and bone.

Cone beam CT is similar to regular dental CT in some ways. They both produce accurate and high-quality images. However, the way in which the images form is different in both the techniques.

The cone-beam CT machine rotates around the patient’s head, capturing all data in one single rotation.

The traditional CT scan collects “flat slices” as the machine makes several revolutions around the patient’s head. This method also exposes patients to higher level of radiation.


  • It helps to guide a tooth implant placement and evaluates cysts and tumors in the mouth.
  • It also can detect abnormalities in the gums, roots of teeth, and jaws.
  • A unique advantage of cone beam CT is its convenient usage.

Cephalometric Projections

These show an entire side of your head on an x-ray. This x-ray looks at the teeth in the jaw and profile of the individual.


  • Orthodontists use this x-ray to develop each patient’s specific teeth realignment approach.
  • Reveal any lateral skull or jaw fracture.

Less commonly used dental X-Rays

The following two X-rays are rarely used in dentistry. But still, they have their unique application and advantages.


This imaging technique uses a dye that your dentist injects into your salivary glands to see them on x-ray film. Dentists may want this x-ray to look for salivary gland problems, such as blockages, or Sjogren’s syndrome.

Sjogren’s syndrome is a disorder with symptoms including dry mouth and eyes; this disorder can play a role in tooth decay. Sialogram also reveals any stones or sialoliths in the salivary gland tract.

Digital radiographs

These are one of the most advanced X-ray techniques. Instead of a standard x-ray film, dentists use a flat electronic pad or sensor.

The image goes into a computer, where you can see it on a screen, store it or print it out. These are convenient to take and save for future reference as well.

Final words

Proper diagnosis leads to apt treatment and excellent results. X-rays are the oldest, cheapest and the most reliable aid for dentists and doctors for diagnosis. There is a particular branch in medicine and dentistry that specializes only in X-rays.


X-rays are a very common diagnostic aid. Hence, it is highly likely that you have already undergone some or the other type of x-ray procedure in your lifetime. There are no potential risks. Although, pregnant females should avoid x-rays as much as possible.

Some studies show overexposure to x-rays can lead to gene mutations. Hence, all x-ray technicians and dentists wear a lead apron or use barriers to avoid x-ray exposure.

Patients, on the other hand, are relatively at no risk because they undergo x-rays for a short time. After taking a look at these numerous types of x-rays, it is safe to say that x-ray imaging is an invaluable diagnostic aid.


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