How does the Dentist Read Peri-apical X-rays?

When we assess your periapical radiograph (PA), what we look for generally depends on the reason we took the X-ray. Of course it is not uncommon to stumble across other things you didn’t know were there in the process.

Possible reasons for taking a PA x-ray could include:

• Pain. One of the first things the dentist will do if you have pain on a tooth after asking you some questions and looking at the tooth is to take this view of the tooth or teeth. It provides all the information of a bitewing and shows the full roots of the teeth too to help accurately diagnose your problem.

• Deep decay. If we took it because of deep decay, we are looking to see not only the depth of the decay and how close it is to the nerve, but also if there have been any changes around the end of the root that could indicate root canal therapy is needed. We assess this by tracing the periodontal ligament space (the very thin dark line that surrounds the root) all the way around and looking for any widening of this space at the tip or signs of infection, such as a periapical radiolucency (a dark circle) that can suggest an abscess or chronic infection from a dead tooth.

• Gum disease. If the bone level was not recorded on the bitewing X-ray it suggests over 4mm of bone has been lost and in this case the full extent of the disease progress needs to be assessed. Sometimes an OPG would be suitable if many teeth were affected as a more general screening view. If a tooth or teeth were mobile and moving, this would be another reason to take this view to look at the amount of remaining bone holding it in.

• Treatment planning crown and bridgework. It is important if you are considering more extensive (and expensive treatment) like this, that the dentist assesses the teeth involved fully, including their periodontal status and bone support and any root canal treatments that have been done or potentially need to be done.When you place a crown, you want to ensure as far as possible that you are putting it on a solid foundation.

• Root canal treatment – PA’s are always required to assess fully a tooth that has had a root canal. They also form a vital part of the root canal procedure in determining the right length to prepare each canal too and in checking the root filling that has been done.

• Tooth Extraction. If it is clear from the examination that a tooth needs to be removed, because it cannot be saved, or you decide not to have a root canal, the roots need to be assessed so the dentist knows how best to approach the extraction. They will look at the number of roots, the shape or curvature of the roots, density of your bone and how close it is to vital things such as your maxillary antrum or ID canal. These elements make up how difficult your extraction is likely to be.

• Dental Implants– This view may be taken as part of the assessment of a dental implant- both before one is done and after it has been completed to monitor the integration with the bone. They will also be taken during the implant procedure itself to ensure the implant is being put in at the correct angle and the abutment is seating down fully.

• Apisectomy – If this surgical procedure for a failed root canal treatment needs to be done then PA’s will be required before, during and after the treatment.