How do dental x rays work


Digital dental x-rays have a significantly lower level of radiation, compared to traditional dental radiographs. That's good news for everyone!

There are three methods of acquiring digital dental images: the direct method, indirect method and semi-direct. The difference is in an electronic sensor that used in a direct method to get an image. The digital sensor allows avoiding the use of x-ray film, minimizing the amount of radiation.

Types of digital dental x-rays

Digital dental x rays can be taken inside(intraoral) or outside(extraoral) of your mouth. Intraoral dental x rays are the most commonly used x-ray in dentistry. They provide great details and used to detect dental cavities (tooth decay), the health of your teeth, bone and soft tissue.

Extraoral digital ray machine does not provide the same depths of details as intraoral x rays and is used to monitor the overall oral health of your mouth. This x-ray can help to monitor TMJ (temporomandibular joints, detect impacted teeth (wisdom teeth), identify potential problems between teeth or check jaw bones and facial bone structure.


Types of intraoral X rays include:

  • Bitewing X rays are taken with the patient biting down on the sensor. It shows details of the upper and lower teeth in the specific area of the mouth. Each bitewing shows a tooth from its top to the bone. Bitewing X-rays are used to detect dental problems such as tooth decay between teeth and any changes in bone density caused by gum disease. Bitewing digital x-ray is also necessary to determine the fit of a dental crown or restorations.

  • Periapical or limited X rays show the whole tooth from the crown to the root tips. Periapical X rays are used to detect root structure and bone structure abnormalities. This digital x ray can show bone loss around the tooth, detect conditions such as periodontitis, advanced gum disease, and detecting endodontic lesions (abscess).

Types of extraoral x rays include:

  • Panoramic (Panorex) X rays requires a machine that rotates around the head and shows the entire mouth, including all the teeth in the upper and lower arch, in one digital image. Pan X-rays allow treatment planning for dental implants, able to detect impacted wisdom teeth and jaw problems and also diagnose bony tumours and cysts.

  • Cephalometric x ray shows the entire head and helps examine teeth in relation to a patient’s jaw and a person's facial profile. Invisalign orthodontic treatment requires a ceph x ray during treatment planning.

  • Cone beam computerized tomography (cone beam CT is also known as cone beam dental x ray) shows the facial structures as a 3D-dimensional image. Cone beam dental x ray — often performed in a dental office or medical imaging center and is used to identify facial bone problems, such as tumours or fractures. Cone beam dental x ray images also used to evaluate bone density for dental implant placement.

The advantage of digital x rays is superior image quality and the ability to control image contrast, unlike traditional x rays. This allows our Burlington dentist, Dr. Alexandra Zemskova for more precise diagnostics and reducing the amount of x rays retakes.

How Many Dental X Rays Per Year?

It is up to a dentist discretion to take a necessary amount of x rays. Our dentist considers case by case the number of x rays required. There is always a reason for that as there is a necessary balance between x rays required to determine proper treatment and avoid unnecessary exposure to ray beams.

Case by case, dentists need to consider patients oral health, smoking habits, patient's diet, when was the last visit to the dentist. Other dental issues can result in taking more frequent dental x rays such as new cavities that keep showing up during regular visits and x rays can help with observations.

In average patient four(4) to six(6) x rays are taken every year to year and a half(1,5). In a healthy patient who comes for regular teeth cleaning the frequency of necessary x rays may be extended up to 1,5 years between retakes.

Does dental x ray affect pregnancy?

Oral radiography is considered to be safe for pregnant patients if a lead apron and a thyroid collar are used, according to the Canadian Dental Association. (

In our Burlington dentist office, we try to abstain from unnecessary exposure of expecting mothers unless it is absolutely necessary. In those rear instances when x ray is required like in cases of a dental emergency, we double up on the lead apron with a thyroid collar and take only limited x rays.

Are dental x rays harmful?

At our Burlington dentist office, we only use digital x-rays. Our latest equipment allows us to provide you with the best that dentistry technology has to offer and minimize unnecessary exposure.

Dental X Rays Exposure Levels

Radiation exposure levels measured in a millisievert (mSv). During our dental exam, you can expect 0.038 Msv from a Bitewing x ray beam, and 0.150 from a full mouth Panoramic x ray. It is hard to give those numbers any meaning without comparing it to other types of x-rays:

  • Chest X-ray - .080

  • Lowe Gastrointestinal track - 4.06

  • Radiation from space - 0.510 (a year)

  • Naturally occurring radiation - 3.00 (per year)

  • The radiation dose rate at typical commercial airline flight altitude (35,000 feet) is about 0.003 millisieverts per hour.

Dental X rays during childhood

Our children's dentist may need to take x-rays to diagnose a trauma or a disease to your child's teeth. Some parents are reluctant to take toddler dental x rays until they get enough information to understand why it is needed. Let's look at some important reasons for your child to get x rays.

X rays are an important diagnostic tool and dentists use guidelines and professional judgement to consider when and how many x rays to take. Before any x-rays are taken, our dentist reviews your child's health history and completes a comprehensive oral exam. There are areas in your child's mouth that a dentist can't see during an oral exam, like inside the teeth and under the gums.

There are good reasons to check these hard to see areas:

  • check for cavities on teeth and between them;

  • check for dental anomalies;

  • check for swellings;

  • evaluate the full extent of the injury;

  • evaluate the health of the bone;

  • determine the number of teeth present;

  • check on previous endodontic or orthodontic treatment;

  • determine the impact of teeth that may not erupt yet;

  • find if teeth have bone loss;

  • check for gum diseases like a periodontal disease;

  • record all findings for continues observation.