How to Improve Your Endodontics in 30 Seconds Flat

Same Tooth, Very Different Images. Taking an Additional Radiograph Provides A Whole Lot More Information

A simple way to improve your endodontics is to simply take two radiographs where you might previously take one. I routinely take two radiographs with differing horizontal angulations when treating potentially multi-rooted teeth (basically everything apart from maxillary incisors) unless there is a reason not to. When dealing with root canal anatomy we’re dealing with a very three dimensional issue, yet a lot of what we plan and assess our treatment on is two dimensionally based. There are so many reasons to take additional views, and in the long run it can make your life easier and improve your endodontics.
The process of taking an additional radiograph adds 30 seconds or less to the radiograph time. You already have the rubber dam folded back and the x-ray tube in place. Developing two radiographs instead of one does not take any longer (especially with digital). More importantly though, you simply have far more information to work with. Additional canals that might not be visible on a standard radiograph will often be visible on a mesial tube shifted radiograph. Where roots that lie close together have differing lengths, this may not be obvious with a radiograph that superimposes the two roots.  Similarly, two radiographs will allow you to determine more accurately which root a lesion is associated with.

Taking an additional radiograph when measuring working lengths is essential, as often files will superimpose on a radiograph and thus, the information on where the file ends relative to the root tip can be lost. This applies for obturation radiographs also.

The image on the right appears to show one distal canal, but the mesial tube shift reveals two separate canals.

Let’s not also forget that occasionally, we may take a radiograph that is not of diagnostic value. For example when the apex of the tooth in question has been missed on the radiograph. The second radiograph may have sufficient information to save you having to re-take the radiographs.
The negative aspect of additional radiographs is the increased radiation exposure for the patient. Obviously, it is important to weigh up the benefits versus risks of taking the additional radiograph, and in my opinion, the potential to improve the endodontic outcome makes the taking of these radiographs imperative.
I was recently sent an x-ray by a referrer who had root filled a vital upper pre-molar, however the patient complained of ongoing discomfort associated with the tooth. The radiograph showed a well condensed root filling that appeared slightly off centre from the middle of the canal. I advised taking a mesial shift of the tooth and the presence of a second canal was obvious. After treatment of the missed palatal canal, the tooth was asymptomatic and ready for restoration. It would have saved quite some trouble, as well as time had the mesial tube shift radiograph been taken prior to, and during treatment.

This tooth remained symptomatic after treatment. Note the obturated canal appears slightly off-centre.

A radiograph taken with a mesial tube shift clearly shows a palatal canal which has not been prepared or filled.

Upon cleaning and shaping of the palatal canal, the symptoms resolved.

I’d love to hear reader’s thoughts on this topic, or case examples where tube shift radiographs have assisted to improve the quality of endodontic treatment. Please leave a comment with your thoughts.