During re-treatment procedures, removing the gutta-percha dry (if possible) is preferred. Simply because it is less messy. But I often find myself use a bit of C-form (what we call chloroform in the office) specially when I have to negotiate the very last part of the gutta-percha close to the apex. I also use it quite often when I re-treat cases with carrier-based obturation material. And, what a mess that creates!
To get rid of this “soup” of gutta-percha from the access cavity and to continue working in a very clean and controlled environment, alcohol should be used as the next irrigant. It clumps up all the softened gutta-percha to the point that it can easily be rinsed off by water spray or picked off by instruments.
Once the gross removal of gutta-percha from the canals is complete with alternating use of C-form and alcohol, I usually use EDTA as it will continue to clean the remaining of the softened gutta-percha from the canal system.
Removing posts from canals could be pain in the neck sometimes. There are many ways to remove a post from a canal such as cutting all the sound tooth structure around the post with a large round bur (I hope nobody is using this method) or using ultrasonic device and frying a few expensive tips and ultimately the root and surrounding structure (can you smell the lawsuit?).
One method that has allowed me to remove stubborn posts more conservatively and relatively quickly is using the Ruddle Post Removal System (PRS) Kit.
The kit comes with a series of post removal trephine burs (#1 to #5) and corresponding post removal tubular taps. The process of port removal starts by removing the majority of the build-up material from around the post. Then a trephine bur can be used to mill the post to a specific size (usually the biggest size that starts to mill the post). The corresponding tubular tap is then used in counter-clockwise direction to engage the post. The tap is screwed in to the point that it locks and starts to disengage the post from the canal. If the post cannot be removed easily, the extracting plier and cushions will do the job beautifully. The short video clip below demonstrates how easily a post can be removed from a canal: