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A Case of Missed Caries, Pulp Degeneration, and Structural Compromise by Dr. Buchanan

A Case of Missed Caries, Pulp Degeneration, and Structural Compromise

Stephen Buchanan, DDS, FICD, FACD





Measuring for Implant

Measuring for RCT


This was an interesting case that presented challenges for the referring dentist and specialist alike. The pt is an 84 YO WM with good general health besides being half deaf. He had RCT in my hands on a molar that is working well. So, because he thought he might have another root canal problem, he referred himself for an exam and testing of his UR cuspid tooth #6. My staff captured PA radiographs and CBCT imaging, both of which revealed external root resorption (note the mottled lucency seen in CBCT-M View) at its mesial CEJ level, cutting nearly halfway through the root and extending slightly above the adjacent osseous crest.

The pt was a well-educated, retired ex-accountant and his first question after hearing what had happened to his tooth, was how could it have been missed by the hygienist during his dental hygiene appointment 3 weeks ago? Before we got to this part of the consultation appointment, I had initially considered it a loser tooth that would be better replaced with an implant than to attempt to do RCT and restore it to its earlier functional and esthetic state (despite being 84, he still wants to look fly). I even measured a mesial CBCT view for vertical bone height from crest to nasal floor and found that a 15mm or even an 18mm fixture would fit, so the case was cleared for implant replacement.

However, when he said he didn’t want an implant and he was mad at his dentist, I took a different look at what was possible: whether #6 could be saved with RCT and a composite resin restoration. The primary concern was the depth of the resorption, which essentially cut halfway through the tooth at the CEJ level, begging the ultimate structural integrity call: can this tooth even hold together after treatment?

entire distal half of the tooth was intact and that I could use the existing defect as an access cavity, thus avoiding further cutting of tooth structure; what I call opportunistic access design. We all love to see perfectly cut traditional access cavity preps, but many endodontists are becoming aware that if we are clever, we can avoid wasting any tooth structure not already lost before treatment.

I was able to negotiate to length, remove the pulp in total, and determine apex locator length with a 31mm length, rotary 20-.06 TF-adaptive File, used only with a lubricant in the canal (no NaOCl). After gauging (measuring) the terminal diameter of the canal with NiTi K-F’s, and finding it to be at least .25mm, I was able to cut a 30-.06 TF-Adaptive File (Kerr Endodontics) to length (in the presence of 17% aqueous EDTA) without further loss of tooth structure, finishing the shaping phase of the RCT. The final canal shape was hardly larger than it was before RCT.

A feather-tipped gutta percha point was cut to a .3mm tip diameter, fit in the prepared canal, and it was cut to a final length 1/2mm from the root canal terminus. A .08 Continuous Wave Electric Heat Plugger was fit to 4mm from length in the canal by rocking it in a buccal to lingual motion which causes the canal to impart a curve in the dead-soft plugger, allowing it to fit to ideal length.

The canal was cleaned with negative pressure irrigation using the new EndoVac Pure (Kerr Endodontics) system. After 30 minutes of irrigation with intermittent freshening of 8% NaOCl, the canal was dried, the master GP cone was cemented to place with Kerr Pulp Canal Sealer, and a cordless Elementfree device was used to downpack through the GP with the electrically-heated CW Plugger, after which the backfill space was obturated with the cordless, motor-driven Elementsfree gutta percha extruder.


#15 K-F 1mm long

Immediate Post-Op

6 Week Recall to Check Soft Tissue Healing


My secondary concern about the case was whether it was possible to restore the mesial apical extent of the defect in a manner that will encourage the soft tissues to heal adjacent to the repair. With today’s glass inomer and hybrid bonded composite materials, we can expect excellent soft tissue healing next to the repair, as long a surgical approach was taken and the restoration has ideal apical margins (see Immediate Post-Op). In this case an oblique releasing incision was cut with a micro-scalpel blade on the DB line-angle of tooth #7, lifting the papilla from between tooth #’s 6 and 7 to make way for placement and finishing of the glass ionomer (Fuji) and hybrid bonded composite (Kerr Restorative). No distal release was necessary. The tissues were returned back to position with three 6-0 Supramid sutures (non-cutting needle is critical when suturing through fragile papilla).

Six week healing was very nice and the esthetics of the polished composite was a dead on shade-match for the dentin root surface that was replaced. To complete my mission, I no charged the patient and told him that his dentist felt badly that the lesion was missed and that he arranged for it to be done by me at no charge to the pt–a little fib but one that made the dentist look like a caring, accountable professional. This was easy to do because; A. The pt’s dentist is awesome and deserves the kudo, B. He does no endo and refers most of it to me, so this was an appreciation move on my part. At the end, everybody was happy.