What are dental X-rays?

High-energy electromagnetic radiation consists of X-rays. In medicine, these are used to visualize the bony structures inside the body.

Dentists and orthodontists take advantage of this technology to inspect what they can’t see when simply looking into your mouth. The X-rays pass through cheeks and lips and are absorbed by teeth and bones, which show up on the image.

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Are dental X-rays necessary?

X-rays are very commonly performed and very helpful. The images, or “radiographs”, that are produced show things like abscesses or decay between the teeth. They not only help to locate, target, and prevent the spread of diseases, but also allow the dentist to perform the procedure safely.

Dr. Eric Moryoussef
Many types of radiographs are considered vital for proper diagnosis. They allow us to catch things like cavities early, before they become a bigger problem.

Some X-rays should be done regularly, others only in certain circumstances. Read on to find out about the most popular ones at the dental office.

Intraoral X-rays

Intraoral means inside the mouth. That’s exactly where the film goes when these X-rays are taken. Intraoral radiographs are the most common and provide the most detail.

Bitewing X-ray

A bitewing is such a common procedure, that it is sometimes referred to as a “check-up X-ray”. That’s because it’s really quick and easy, but also because it gives the dental professional a lot of information.

Tooth decay happening on the inside of your tooth can be easily diagnosed. Changes in bone thickness, signs of gum disease, and decay between the teeth will also show up on the image.

Dr. Jason Chong
Bitewings are recommended every other cleaning visit, or every twelve months to evaluate for caries and to identify subgingival calculus.

A bitewing captures a small section of the lower and upper teeth. If you aren’t focusing on a problem area multiple can be taken for a general overview. Additional radiographs are usually less expensive than the first one.

The name stems from the shape of the device you put into your mouth. You will bite down on a wing-shaped piece of film. The dentist or hygienist will leave the room for each snapshot and you might wear a protective bib.

Bitewing X-ray
How often you should have itOnce a year, as determined by your dentist
What it can detectGum disease, calculus (a.k.a. tartar), and decay between the teeth
Related proceduresScaling and root planing, professional teeth cleaning, cavity filling, veneers placement, crown placement

Periapical X-ray

A periapical X-ray shows a small section of the mouth, it concentrates on one or two teeth. The entire tooth from the crown to the tip of the root (below the gums) will be visible.

It may help diagnose issues you didn’t know you had. Most often it is taken when the patient experiences acute pain. This could be undiagnosed pain or pain that is suspected to be caused by failure of prior treatment.

Dr. Jason Chong
Periapical images are usually taken to assess roots and root issues like endodontic lesions.

The dental professional will leave the room. You might have to wear a protective bib, one covering your thyroid gland at least. The film will usually be mounted on a metal rod with a ring. You will have to bite down on the device. This will help it stay still.

You will probably need more than one picture. Additional radiographs are usually less expensive than the first.

Periapical X-ray
How often you should have itOne or two times a year, if you experience pain
What it can detectImpacted teeth, fractures, abscesses
Related proceduresTeeth whitening, SRP, RCT, veneers placement, crown placement, tooth extraction

FMX

Sometimes the dental hygienist or dentist will decide that rather than taking individual periapical or bitewing X-rays, an FMX is needed.

FMX means a full-mouth series of X-rays. It includes a set of sixteen to eighteen images to observe the full set of teeth and the surrounding tissue. These usually include four bitewings and twelve to fourteen periapicals.

Dr. Namrita Harchandani
An FMX is always helpful to get the bigger picture. I would perform it if a new patient hasn’t had full mouth series of X-rays done in the last three to five years.

The radiographs will show the structure of your entire mouth as well as details of individual teeth. The jaw will be presented from both sides. This will give the dental professional a good idea of the general structure of your mouth.

The procedures will not differ from what has been described above. Some offices you require you to have an FMX if you are a new patient. For established patients, four bitewings and two periapicals (of the front teeth) are usually taken every six to twelve months.

FMX
How often you should have itWhen you are a new patient or every 3 to 5 years after that
What it can detectAbnormalities in the structure of the mouth, decay, gum disease, abscesses
Related proceduresInitial dental exam, orthodontic work

Occlusal X-ray

This type of X-ray concentrates on tooth development. Each radiograph shows an entire arch, upper or lower.

It is mainly done in children who are experiencing problems related to unusual tooth alignment. It also captures unerupted teeth, or teeth, that are erupting in unexpected places. The image shows the roof or floor of the mouth.

Occlusal X-ray
How often you should have itOnly if the situation requires it
What it can detectCaries below the gumline, fractures in the jawbone, abscesses, foreign objects
Related proceduresOrthodontic work, cavity filling

Extraoral X-rays

For the following three types of X-rays, the film remains outside the mouth. These show the teeth as well as the surrounding structures such as the jaw and skull.

Panoramic X-ray

A panoramic X-ray is a very common procedure at the dental office. They provide a big-picture view that shows the relationship between the jaws and teeth, as well as the airways such as the nasal cavities and sinuses. This is a non-invasive test that is the way to go if you are unsure which tooth is hurting.

Dr. Namrita Harchandani
A panoramic X-ray provides extensive information about your jaw bones, joints, and underlying dental diseases.

It requires little preparation. You will have to remove your jewelry, glasses, and other metal objects. You will be given a lead apron to protect the rest of your body from radiation exposure.

You might have to stay standing for this X-ray. Your head and chin will be placed in a device that will help you remain motionless. This is vital, as any movement could distort the radiograph.

Even though the device will rotate around you, all teeth will be shown on a flat radiograph. The image will show both arches along with surrounding structures and tissues.

Peter Dégallier, dental therapist
A panoramic radiograph is very helpful for teenagers. It can assess tooth eruption and orientation, particularly of the wisdom teeth.

You will probably have it if you decide on a dental procedure that will require a comprehensive radiograph, such as a dental implant. Many orthodontists like to do a panoramic X-ray before performing any orthodontic work.

Panoramic X-ray
How often you should have itOnce every 3-5 years
What it can detectImpaction, crowding
Related proceduresCavity filling, RCT, veneers placement, tooth extraction, implant placement, orthodontic work

Cephalometric projections

A “ceph”, as it is sometimes referred to, is usually taken before and after orthodontic treatment. This X-ray concentrates on the patient’s profile and helps predict the outcome of tooth movement.

Exposure takes approximately ten seconds, and the image is developed in about five to six minutes. It will be two-dimensional.

The dental professional will use tracing paper to “trace the ceph”. The movement of the dentition and its growth patterns can be calculated.

Cephalometric projections
How often you should have itBefore and after tooth alignment treatment
What it can detectTooth movement
Related proceduresOrthodontic work

Cone-beam computed tomography (CBCT)

A cone-beam CT is often confused with a medical CT scan, though it produces a lot less radiation. It provides considerably more details than other types of dental X-ray, as the image produced is 3D.

It is used when other types turn out to be insufficient. During the procedure, a beam in the shape of a cone will move slowly around your head. You will have to remain motionless for the shot to be clear.

Three radiographs are captured in a single scan. Those pictures, or “views”, are then combined to produce a three-dimensional image. The dentist will be able to assess space and internal structures in the mouth. The teeth, soft tissues, nerve pathways, and bone will all be visible.

Dr. Henry Hackney
Cone beam X-rays are the most detailed, accurate, and diagnostic form of radiograph. This type of X-ray is very helpful in implant placement.

The dentist will also be able to see which direction the roots grow in. This makes oral surgery less invasive; it is easy to see where the incisions have to be made.

A cone-beam CT is particularly helpful with implant placement and wisdom tooth extraction. Some complications, such as permanent nerve damage, can be more easily avoided if this X-ray is done.

Cone-beam computed tomography
How often you should have itBefore oral surgery only
What it can detectAbnormalities in root growth and structure
Related proceduresOral surgery, wisdom tooth removal, implant placement, RCT

Digital radiography

Digital radiography is a new technology that might one day replace traditional X-ray film. It’s not a type of radiograph but a different means of taking one. You can, for example, take a bitewing this way.

The advantages include the fact that images are processed immediately, so they can be viewed straight away. These images are editable; the technician can adjust contrast and deduce more information from the radiograph. There is no real difference in terms of price for the patient.

The biggest disadvantage is that some of the sensors are bigger and bulkier than traditional ones. This means it is less comfortable for the patient and that it can’t easily be disinfected. The device is covered in disposable plastic which is necessary for infection control.

Digital radiographs expose the patient to significantly less radiation than traditional film radiographs.

Are dental X-rays safe?

Generally, there is a lot of misconception around radiography. The radiation produced during an X-ray is very small, comparable to the amount you would experience during a sunny day. The exposure from four bitewings is comparable to a two-hour airplane ride.

ItemDose of radiation in Millisieverts (mSv)
Banana0.00001
Dental X-ray0.005
A flight from New York to Los Angeles0.04
Mammogram0.3
Abdominal CT scanr14

Resource: RDH Magazine

What’s more, the benefits of early detection of any issues outweigh the risk of a minimal amount of radiation. There is also no reason to be worried about children getting X-rays. Radiography can be safely used in pediatric care.

The biggest contraindication to X-rays is pregnancy. Still, accommodation can be arranged if necessary. For example, if there is an emergency or a woman becomes pregnant during a long-term treatment she and the baby will be protected by a heavy-duty leaded apron and a thyroid collar.

In your experience

X-rays are pretty common in medicine, and in dentistry too. They are the best way to ensure safety during complicated surgeries.

The chances are you have already had one during your lifetime. Comment down below what your experience was like.