How to read dental x-rays: what do cavities look like? (2023)

Stage.

You may have gone to your dentist for a checkup. They have had X-rays (dental term for x-rays) taken and you have just been told that she has cavities.

Your dentist will show you pictures of your teeth so that you are fully informed. But the problem is that you don't really know what to see or what to look for.

The interpretation of dental X-rays requires some skill.

We can't make you an expert, but this page describes how dentists read X-rays.

Describe:

• What dentists look for in X-rays(The progressive stages of cavitation.)
• Why what is seen appears in the image.
• yes yesreal examples of caries visible on bitewing radiographs(the standard type of X-ray used to find them).

This page is also discussedCurrent guidelines on how often bitewing radiographs should be taken..

How to detect cavities in dental x-rays.

The underlying premise is this...

When looking for a cavity in a tooth, a dentist looks for signs on the x-ray that suggest or suggest that the density of some of the tooth's calcified hard tissue (enamel and/or dentin) is different than normal or expected.

How does dental radiography work?

When a dentist takes an X-ray, the hard mineralized tissue of a tooth blocks some of the radiation (X-rays) that has been directed through it.

Due to this effect, the parts of the X-ray film (or digital image receptor, the more modern way of taking an X-ray) that lie behind these heavily calcified tissues are less exposed (less X-rays hit them). ).

This makes these protected parts of the image appear clearer. (These areas of the film do not darken as much because fewer x-rays were able to pass through the tooth to reach them.)

On an x-ray (see figure):

• The outer enamel of a tooth shows the lightest color. This is because it has a higher mineral content than the other parts.
• In comparison, the dentin layer (a less calcified tissue) appears slightly darker on film.
• The outline of the cavity in a tooth (its pulp chamber, the place where nerve tissue resides) appears darker.

  This is because in this area, much of the thickness of the tooth is non-calcified soft tissue, allowing a higher percentage of X-rays to pass through this area and expose the film.

Why cavities can be seen on x-rays.

Because dental caries is an area of ​​the toothdemineralization(an area of ​​low mineral content) or possibly even a true hole (a space that would have no mineral content), the places where it formed will show up as a dark area on an x-ray.

This is because the decayed part of the tooth is less "hard" (less dense or intact) and therefore X-rays penetrate that part of the tooth more easily, ultimately exposing more of the film (making it the corresponding area appears darker on the film). ).

When evaluating an X-ray image:

• The clue to the dentist that there is a problem is that the dark area on the image is at a point or aspect of the tooth that in health would not be expected to be less dense (reduced mineral content).
• And characteristically, there are certain areas on a tooth that are more prone to decay than others (like right in the contact area between two teeth). So when the dark dot matches that kind of location, it's particularly telling.

Cavitation stages appearing on x-rays.

Our model of a dental X-ray illustrates some of the stages the caries process goes through.

• Table A:This chart shows the earliest stage of caries formation that can be seen on a dental X-ray.

  Notice that there is a slightly dark area in the enamel area of ​​the tooth just where it touches its neighbor (the contact point). This is decadence. (This person did not floss enough.)

  Most dentists do not recommend placing a filling until the x-ray shows that decay has fully penetrated the enamel layer of the tooth (as shown in image B). The lesion shown in Image A may not progress further once this person starts flossing.

  (Video) How To Understand Your Dental X-rays (Dental Hygienist Explains)

• Table B:Once the x-ray shows that decay has penetrated through the enamel layer of the tooth and into the dentin, a dentist will usually recommend placing a filling (see discussion below).

• Box C:As mentioned above, the dentin portion of a tooth is less mineralized (less "hard") than the enamel layer of a tooth. And because of this, it will disintegrate faster.

  This phenomenon shows up on radiographs. Note that in image C, the lesion in the enamel layer has only slightly increased in size, while the caries in the dentin portion of the tooth has progressed significantly.

  It's especially important to treat an injury like this right away, before it spreads to the point where it significantly compromises the structural integrity of the tooth or damages its nerve.

• Box D:Table D illustrates a worst-case situation.

  If a developing cavity is not treated, it can progress to the nerve tissue of the tooth. If this is the case, it is not only necessary to remove the decay and repair the damaged tooth structure, but also to clean the tooth.root canal.

  Early caries treatment (preferably at the point shown in image B) is clearly a case where a point nine saves time.

▲ section references-Weiss

What kind of treatment is needed on this X-ray?

By reading this image, a dentist would diagnose the need for the following work.

• circle A– The “notch” in the 2nd molar would be classified as a “clock” or incipient lesion.

  The fact that some caries has already formed is worrying. The dentist will need to keep a close eye on this area on future X-rays to make sure the lesion has not progressed further.

  Treatment with some form of preventative measure is indicated to prevent further progression. (This may include: topical applications of fluoride, applications of amorphous and reactive calcium phosphate complexes, use of synthetic hydroxyapatite in an acid paste to repair the defect.)

• Circles B and C– The extent of the carious process in these areas has clearly penetrated the enamel layer of the tooth. And due to this fact, the underlying dentin of the tooth is now clearly involved as well.

  In the past, these types of lesions were considered complete caries and, as such, an indication for the placement of fillings. Today, techniques such as resin infiltration could be used instead to try to slow the progression of these lesions. If this is the case, future follow-up with X-rays will be necessary.

• for your information– The very white objects on this X-ray are existing metal (amalgam) fillings in your teeth. They appear bright white because the metal in the filling is so dense that few or no x-rays can penetrate it and expose the x-ray film/sensor.

▲ section references–Hilton

"Bite" X-rays.

The film shown here is the same X-ray as above. In dental terminology, it is called a "bite" radiograph. This is the standard image type used to search for voids.

• The name "bite" comes from the patient biting on a tab (a single "wing") attached to the foil or digital sensor. This holds it in place while the picture is being taken.
• Bitewings are the only type of routine intraoral dental X-ray that shows both the upper and lower teeth. (“Intraoral” means that the film or sensor is placed in the mouth when the exposure is taken.)
• The intent is to show the crowns of the teeth (the part of each tooth that protrudes beyond the gum line) as well as the jaw ridge that surrounds them and holds them in place.

  (Regarding caries detection, when complete, the image will show the full extent of each tooth where caries may begin.)

• A primary purpose of taking bitewing radiographs is to detect cavitation in the general area of ​​the point of contact between two teeth.

  (This is a location that the dentist cannot directly visualize and is often difficult or impossible for the dentist to fully examine clinically. Therefore, taking bitewing radiographs may be the only method available to adequately assess this region.) .

• After taking the photo, the goal of the technician is to split the contacts for the photo. This refers to aligning everything so that the point of contact between all the adjacent teeth can be clearly seen.

  (In cases where the X-ray machine is misaligned, the teeth will appear overlapping. This makes reading the X-ray much more difficult, if not impossible. For example, it is possible that small changes like the one in circle A in our image above not being detected at all.

▲ section references–Blanco,care page

How often should bitewing x-rays be taken?

X-rays shouldn't just be an eternal, automatic profit center for your dentist. They should be taken instead for specific reasons.

The authority.

Fortunately, through a collaboration between representatives from the American Dental Association (ADA) and the US Food and Drug Administration (FDA), there are a number of guidelines that dentists must follow. They are titled:"Dental X-ray Examinations: Recommendations for Patient Selection and Limiting Radiation Exposure".

What are the guidelines for taking bitewing radiographs as a tool to detect caries?

The need for a dentist to take bitewings during a dental examination should be based on...

• The age of the patient, or more specifically what type of teeth the person currently has. (Milk teeth only, a mixture of deciduous and permanent teeth, or permanent teeth only.)
• What previous x-rays exist and what access does the person's current dentist have to them?
• What was seen during the patient's current oral examination?
• The patient's dental history, including their historical experience with cavities and the amount of dental work required.

How often should you eat bites? - case studies.

1) Adult review patients.

The term "recovery" as used in this context refers to a dental appointment to which the patient has returned for regular checkups. (An interval of 6 to 12 months is common.)

It bites the wings every 24 to 36 months. –If no caries is detected during the patient's clinical examination and there are no associated factors that put the patient at increased risk of developing caries.

Bite the wings every 6 to 18 months. –If dental caries is detected on clinical examination or it is suspected that the patient has associated factors that put them at increased risk of developing dental caries.

2) New adult patients.

"New" patients are people who are new to a dental practice and therefore the dentist has limited knowledge of the individual's caries history and does not have historical radiographs as background information.

The use of bites is generally indicated. –Especially if caries was found during the clinical examination of the patient.

3) Adolescent patients called for review: only permanent dentition.

This category consists of young people who have lost all their milk teeth.

Bite the wings every 18 to 36 months. –If no caries is detected during the patient's clinical examination and there are no associated factors that put the patient at increased risk of developing caries.

Bite the wings every 6 to 12 months. –If dental caries is detected on clinical examination or it is suspected that the patient has associated factors that put them at increased risk of developing dental caries.

4) New young patients: permanent teeth only.

The use of bites is generally indicated. –Especially if caries was found during the clinical examination of the patient.

5) Recovery of adolescent patients - transitional dentition.

The term "transitional dentition" means that the person has some permanent teeth but also retains some deciduous teeth.

Bite the wings every 12 to 24 months. –If no caries is detected during the patient's clinical examination and there are no associated factors that put the patient at increased risk of developing caries.

Bite the wings every 6 to 12 months. –If dental caries is detected on clinical examination or it is suspected that the patient has associated factors that put them at increased risk of developing dental caries.

6) New young patients - transitional dentition.

The use of bites is generally indicated. –Especially if caries was found during the clinical examination of the patient.

7) Child withdrawal patients: deciduous teeth only.

This group of children is characterized because they only have milk teeth. Note: Some children have spaces between all of their baby teeth. If this is the case, x-rays are not needed to assess decay.

Bite the wings every 12 to 24 months. –If no caries is detected during the patient's clinical examination and there are no associated factors that put the patient at increased risk of developing caries.

Bite the wings every 6 to 12 months. –If dental caries is detected on clinical examination or it is suspected that the patient has associated factors that put them at increased risk of developing dental caries.

8) Child withdrawal patients: only deciduous teeth.

The use of bites is generally indicated. –Especially if caries was found during the clinical examination of the patient.