One of the challenging tasks in non-surgical retreatment is the removal of cast posts, especially if it’s done through the crown. The challenge is to go through the metal, then cut and isolate the post at the pulpal floor level without damage to the surrounding tissues. The following case is an example of such treatment completed yesterday.
A 29 year old healthy male reported a history of recent pain and swelling associated with tooth #3. He was taking Amoxicillin 500 QID. Previous root canal was done years ago. On examination #3 was tender to percussion and palpation with normal perio probings. Crown is adequate with no opened margins or decay. Patient was scheduled for non-surgical retreatment of tooth #3.
Pre-op #3
Pre-op image clearly shows a large post, very likely a cast post, periapical area on buccal and palatal roots. Oftentimes, case like this (large post) will have a periapical lesion on the buccals (typically due to untreated MB2) and not the palatal, and so I would treat buccal canals only and leave the palatal alone. There was no such luck on this one.
The access cavity was prepared using the following burs and tips: round diamond #4, several H34 (double striped) transmetal burs and an endo access bur #4 (all from Komet USA), then refined with buc-1 ultrasonic tip. Cast post was then cut at the pulp chamber floor and isolated from the core as shown on the image below.
Post isolated
Generally, when I retreat cases involving post removal, after access preparation, I go for the post before removing root fillings to avoid any metal shavings going into other canals. In this case, post was removed using ultrasonic instruments (ET20D and Buc-1 tips), troughing around the post and vibrating it out.
Post is ready to go
7mm post (from the pulpal floor apically)
Once the post was out, canals were cleaned and shaped using a combination of Protaper and hand files, finishing at the following sizes: MB1 and MB2 #55, DB #60 and P #110. All canals were finished by hand, gauged, and .02 tapered gutta percha with pulp canal sealer was used for obturation.
Conservative access opening, 4 canals
Using water bending or prism effect, discussed in one of the previous posts, four canals are shown on the image above.
Post-op
Image above shows retreatment of tooth #3 completed. Periradicular radiolucency on tooth #4 should be treated surgically at a later date.
