What types of digital dental X-rays are there?
Three types come up most at a dental visit, and each answers a different question.
| Type | What it shows | When the dentist uses it |
|---|---|---|
| Bitewing | The crowns of your upper and lower back teeth, and the bone level between them | Decay between back teeth, bone levels |
| Periapical | One or a few whole teeth, crown to root tip | A toothache, a suspected infection, planning a root canal or extraction |
| Full-mouth series | Bitewing and periapical images that cover every tooth | A detailed record when the exam shows a reason, such as gum disease |
Bitewings get their name from the wing-shaped tab on the films once used. For each image, a team member places a small digital sensor in your mouth and asks you to bite down or hold still. The X-ray unit points at your cheek, and you feel no light or heat from it.
The sensor has firm edges and can press on your gums. Tell the team if it hurts or makes you gag.
What are the benefits of digital X-rays?
Digital X-rays put the image on a screen within seconds, with no film to develop. Your dentist can enlarge it and show you the area of concern while you are still in the chair.
Digital sensors also work at a lower dose than film. Health Canada's Safety Code 30 sets an achievable dose of 0.8 mGy for a bitewing or periapical image taken with a digital sensor. The figure for fast film is 1.2 mGy. These are benchmarks for an average adult, measured at the end of the X-ray tube, not your own dose.
Digital files are easy to share with other dental offices involved in your care.
When dental X-rays may be recommended
Dental X-rays are not needed at every visit. Your dentist decides after looking at your symptoms, dental history and treatment needs. Common reasons include:
- you are a new patient with no recent X-rays from your last dental office
- tooth pain or sensitivity with no clear cause
- a suspected cavity between teeth
- signs of gum disease or bone loss
- planning a crown, bridge, implant or extraction
- checking wisdom teeth or other teeth that have not come in
- checking healing after treatment
How dental X-rays support preventive care
Dental X-rays can show small problems before they cause pain or need bigger treatment.
- hidden decay between teeth
- signs of infection around a root
- changes in the bone that supports your teeth
- a child's tooth development, when the exam gives a reason
- changes over time, by comparing images
How often should you get dental X-rays?
No fixed schedule fits everyone. Your dentist sets the timing from your history, your exam and your risk of decay and gum disease.
Safety Code 30 says an X-ray should follow a clinical exam that shows an expected benefit to you. Routine screening X-rays without that exam should not be done, including for children. Someone with frequent cavities or gum disease may need images at shorter intervals than someone with healthy gums.
The code also asks dentists to look first for recent X-rays from another office. Had X-rays elsewhere recently? Tell the team when you call (905) 581-2228.
Are dental X-rays safe? Radiation dose compared
Dental X-rays use a very low dose of radiation. The Canadian Nuclear Safety Commission puts one intraoral dental X-ray at 0.005 mSv. Natural background radiation in Canada averages 1.8 mSv a year.
| Source of radiation | Dose stated by the Canadian Nuclear Safety Commission |
|---|---|
| One intraoral dental X-ray | 0.005 mSv |
| A cross-Canada flight | 0.02 mSv |
| A chest X-ray | 0.1 mSv |
| Natural background radiation in Canada, one year | 1.8 mSv |
Low is not zero. Health Canada treats any radiation dose as carrying a very small cancer risk. Safety Code 30 asks dental offices to keep every dose as low as reasonably achievable and to take only the views a diagnosis needs.
Do you need a lead apron or thyroid collar?
Health Canada's current guidance says you should get a thyroid collar whenever it will not block what the dentist needs to see. A lead apron is not required for routine dental X-rays, because abdominal shielding does not change your dose in a meaningful way. Safety Code 30 allows one for comfort, so ask if you would like one.
Can you have dental X-rays while pregnant?
Tell the team before any X-ray if you are or could be pregnant. Safety Code 30 says it is generally accepted that the dose reaching the fetus from dental X-rays is extremely low when the abdomen is not directly exposed.
The code also quotes the Canadian Dental Association: "Elective procedures may be deferred until after the pregnancy. Pregnant patients requiring essential and/or emergency treatment should receive the minimum number of radiographs needed for diagnostic purposes."
Do children need dental X-rays?
Children get dental X-rays when the exam shows a reason. Safety Code 30 says X-rays should not be taken just to monitor a child's tooth development. It calls the thyroid collar especially important for children, whose thyroid is more sensitive to radiation.
A young child may need help to stay still. The code says any parent who helps should wear a protective apron and stay out of the beam.
Questions before your visit? Call (905) 581-2228.
What can dental X-rays not show?
Dental X-rays do not show everything. An X-ray is a flat picture of a three-dimensional area, so one structure can hide another. Gums, cheeks and tongue do not show in detail, so your dentist checks them by eye and touch.
An X-ray misses some very early decay. That is why X-rays are one part of early cavity detection, alongside a close look at each tooth. Research on periapical X-rays also finds good accuracy for root-tip infection, not perfect accuracy. A clear image does not rule an infection out.
What do dental X-rays in Vaughan cost?
The cost of dental X-rays depends on the type and the number of images your dentist orders. A pair of bitewings costs less than a full-mouth series of 12 or more images. Your own cost comes in a written estimate after an exam.
Why do X-rays at the dentist cost what they do? Fees depend on the type and number of images, and every dentist sets their own fees.
Your written estimate lists the charges. OHIP does not cover dental services provided in a dentist's office, so without a dental plan you pay the office's fee yourself. My City Dental offers direct insurance billing for patients with a plan.
The Canadian Dental Care Plan (CDCP) can cover qualifying dental X-rays for eligible patients. Its guide sets frequency limits for each type, such as one complete series in any five years. Coverage depends on the service and your eligibility, and some services need preauthorization.
Frequently asked questions
Can I get a dental X-ray without a doctor's referral in Ontario?
Yes. You do not need a referral from a family doctor for dental X-rays. A dentist orders them after reviewing your history and examining you, and the X-rays are taken at the dental office.
Some dental imaging is done at separate imaging centres on referral. If another dentist asked you to get a specific X-ray, call first to check whether the office takes that type.
Should you get X-rays at the dentist?
Yes, when your dentist finds a reason for them at your exam. Skipping a needed X-ray can leave decay between teeth, a root infection or bone loss untreated until it hurts. You can also say no to an X-ray. Ask the dentist what the image will show and what could happen if you skip it, then decide together.
Can a dentist see a tooth infection on an X-ray?
Yes, in many cases. An infection at the tip of a root shows on a periapical X-ray as a dark area in the bone around the root. Some infections are too small to show yet, so the dentist combines the image with your symptoms and tests on the tooth. Call the office promptly if a tooth aches and the gum or face around it starts to swell.