There are some frustrating experiences that every dental professional faces during root canals. For instance, ever run into surprise apical calcification and curvatures? These unexpected finds can really complicate your access. Within teeth, some curves are drastic and obvious, while others are more subtle. Unfortunately, it’s the subtle ones you have to watch out for! They’ll make you feel like you’re doing something wrong, so you have to know what to do when you get stuck.

Recently, a dentist reached out to me asking about a case. She was doing a root canal on tooth #13. On the radiograph, the tooth looked pretty straightforward, but she discovered it wasn’t at all! She sent me this image, a working length radiograph of tooth #13.

Rest assured, my FIRST question to her was, “Where is your rubber dam?” She let me know she clamped a different tooth, so you simply can’t see it.

One of the canals was close to patency, but I wasn’t convinced it was patent yet. The other canal was short, and therein lay her frustration.

This kind of working length issue happens to me every day, and it’s important to know how to troubleshoot it because it never stops occurring.

When you can’t get to length, here are the 8 tricks for apical calcification and curvatures in root canals that I shared with her. Now I’m sharing them with you:

1. Use smaller files. Not having any luck with your 10 file? It’s time to think smaller so you can get down to that apex. I use 6 and 8 files all the time. If something’s really calcified, then I’ll use a 21mm hand file over a 25mm one; the shorter files tend to work better for these situations.

2. Toss the K files and get C ones. That’s “C” for “cutting,” which is exactly what you need for getting through that apical calcification to 0.0. Rather than the “quarter turn pull,” this file needs to be used in a pecking motions. (More on my Top 10 Tools for Endo here.)

3. If the tip of the file gets bent, then cut the tip off and keep using the file as-is. This will keep your tip more active and help it cut more efficiently. Don’t forget that you just shortened your file, though! This is also a great way to get more life out of your file instead of reaching for a new one.


4. When your hands get tired, use the M4 Handpiece! It’s freakin’ awesome! It basically turns your hand into a rotary file, so that it can bust through those calcified canals and get you down to apex. (You’ll want to make sure you keep that pecking motion when you use it.) Here’s one one put out by Kerr, but you can obviously reach out to your dental supplier for more options.

5. Curve your files beforehand. Straight files can get stuck, especially if you’re dealing with a curvature issue. Try precurving the file and see if that helps.

6. Start with a coronal opening. Want your hand file to glide to the apex with ease? Things will become a lot more simple if you’ll remove the coronal interferences. While you may have to go back and forth some between your rotary and your hand files for this process to work, don’t go too quickly and stress your files (or cause separation). It will take time and patience, but it could be the key to get you to that apex.

7. Use some EDTA. Let it soak in the canals for a few minutes, then work your files in while it’s still there. It certainly won’t hurt, and it just might make all the difference.

8. Put it aside for another day. Sometimes, when you’ve been working on a tooth for a long time, you just need some time away from it. If none of these tactics work, then place some calcium hydroxide and be done. At the next appointment, you’ll have fresh perspective (and a fresh set of eyes) to help you conquer crazy apical calcification and curvatures!

Hopefully, these tips and tricks for dealing with constricted canals will be helpful and get you unstuck. Don’t give up! Remember, your goal is to save teeth! Working length and patency are so important to root canal success. 

You can do this!