Acute curvatures are a part of doing endodontics. The more cases you treat, the better the chances that you will encounter them. These curvatures are not limited to molar teeth, but can occur anywhere in the mouth. Often we see the dramatic postoperative radiographs, but how do we get to that end point?
The first thing you want to do is remember to carefully evaluate your preoperative radiograph. After doing a procedure many times, it is easy to take a cursory look at the film. I always try to review preop radiographs prior to entering the room. This allows me to start to think about what I see on the films and then once I am in the treatment room, I am able to combine my clinical impressions with the radiographs.
Sometimes you can identify the curvature and be prepared for what you are going to run into. Unfortunately, curvatures are not always apparent until you get into the case.
The next step is ensuring that you have proper access. You will note that I don’t say straight line access, as I think we have to balance the removal of tooth structure with our need to complete endodontic treatment. With that said, it is imperative that you are not fighting to get instruments into the coronal third. Whether this is mitigated through the use of an orifice opener, troughing apically or the judicious removal of tooth structure, a repeatable path into the canal is imperative. Once this is achieved, I will often use a brief sequence of crown down instrumentation using #10 and/or #15 K files. I may combine this with some initial rotary instrumentation. This is not an effort to negotiate the apex, but rather to improve access to the curvature and reduce coronal interference.
One of the techniques I have used over the years is taking an “apical impression”. I am not sure where I learned this, but once you have good access to the apical third, you can scout the area using smaller handfiles. I will often place a #10 file and instrument briefly using only a few turns of balanced force. I then will apply force apically to the file and will remove it. This gives me an idea of the degree and location of the curvature.
Some additional thoughts when instrumenting these cases:
1. Patency be established and maintained throughout.
2. Frequent irrigation and recapituation coupled with small diameter instruments, both NiTi and Stainless steel.
3. Decrease the increment that you attempt to advance down the canal. In a straight canal when working crown down, you may be able to advance a significant number of mm between instruments. When dealing with severe curves, don’t try to bite off too much at one time. Take small bites and work your way down the tooth. Patience is imperative.
4. Small diameter instruments should be your workhorses in cases like this. Their flexibility is invaluable (I know I said this in #2, I’m repeating it because it is important).
It is golf season here in Northwest Ohio. As a result, I expect to be posting a bit less in the coming months. After the winter we have had, whatever your favorite activity is, I hope you have a chance to indulge.
On a parting note, how about those Huskies!!! If one championship is good, how much better is two!
