Patient: 52 year-old male in excellent health

Chief Complaint: Patient reported a bump on the gums above his front upper tooth

Dental History: Patient reported a history of prior orthodontics as a child and previous endodontic treatment performed on the maxillary left and right central incisors in 1970 (teeth #’s 8 and 9). Surgical endodontic treatment had been performed years ago after a recurrent infection associated with the maxillary left central incisor (tooth #9)

Significant Findings (teeth #’s 8 and 9): Percussion and palpation tests were within normal limits for both teeth. Periodontal probing depths were within normal limits for both teeth. A fistula with drainage was noted at the apical extent of the attached gingiva opposite tooth #9. Radiographic findings revealed slight PDL space widening with a slightly short root canal filling associated with tooth. Tooth #9 revealed a diffuse periapical radiolucency with a root filling filled 2-3 mm short of the radiographic terminus and a suspected “blunderbuss” apex.

Pulp and Periradicular Diagnosis: Previous root canal fillings (teeth #’s 8 and 9) with a questionable periapical status (tooth #8) and a chronic periradicular periodontitis with a draining fistula (tooth #9)

Treatment Prognosis: Good (tooth #8), Fair (tooth #9)

Treatment Plan: Nonsurgical endodontic retreatment (tooth #8), Nonsurgical endodontic retreatment with post removal (tooth #9)

Special Considerations of Performed Treatment:
It is not uncommon to encounter surprise complexities after beginning nonsurgical endodontic retreatment. Teeth having previously placed posts and prior attempts at retreatment (especially surgical) are higher risk that teeth that had been previously treated without posts and without follow-up endodontic surgery. If a prior retreatment attempt had failed the prognosis for treatment success on another attempt is less favorable. If there is an obvious previous treatment error that can be corrected then the prognosis for retreatment is more favorable than a case which appears to have been previously performed with expertise.

In this case the previous endodontic treatment performed on the right maxillary central incisor (tooth #8) was suspect but not obviously failing. The left maxillary central incisor (tooth #9) appeared to be high risk with a poorer prognosis because there were no obvious treatment errors observed with the examination findings and there had been a previous surgical endodontic retreatment attempt. Tooth #9 was obviously failing with recurrent endodontic pathosis evidenced by a draining fistula.

This case will be divided into two parts as it presents interesting questions to be answered as a “puzzle case”:

April 24, 2014: The first visit of retreatment in two steps was performed on both teeth #’s 8 and 9.

Tooth #8: Removal of the previous root canal filling material in the root was uneventful, cleaning, shaping, and placement of intracanal calcium hydroxide was routine.

Tooth #9: Note the sequence of images showing the author’s “staging and penetration” technique used to remove the cast metal post in tooth #9. Once the post was removed there was a noticeably large accumulation of gutta percha inadequately sealing the reverse-prepared labial aspect of the root. Meticulous debridement of debris was performed with copious flushing of sodium hypochlorite. A retentive composite build-up portion of the crown de-bonded and was removed. Calcium hydroxide was placed, the canal orifice sealed with Cavit, and the temporary crown recemented with Duralon cement. When the rubber dam was removed calcium hydroxide could be seen streaming out the draining fistula.

May 27, 2014: A short examination appointment was scheduled to verify that he fistula had healed (it had) and the second treatment appointment was scheduled to obturate both teeth #’s 8 and 9.

June 5, 2014:

Tooth #8: Obturation and completion of endodontic retreatment was uneventful and an apical demonstrably filled lateral canal was noted.

Tooth #9: The temporary crown and temporary core were removed. Once the root canal system was cleared of calcium hydroxide and dried, an apically propagated crack was noted.

A treatment puzzle was then presented:

What would you do next?

June 5, 2014 (continued): The clinician has to be prepared to change a treatment plan based upon new findings. In this case the patient was informed of the crack and the prosthodontist treating the case was called. The patient was highly motivated to save the tooth and accepted the risks (the tooth was reassessed as having a guarded prognosis). The crack was microscopically prepared with an ultrasonic file, and the irregular root canal space filled to the bleeding point with Biodentine (tricalcium silicate with enhanced physical properties). A layer of Geristore was placed over the coronal surface of the Biodentine. After curing of the Geristore a Cavit filling was placed in the access and the crown was recemented with Duralon. The patient was referred back to his dentist (prosthodontist) for a build-up and new provisional crown.

Recall:

July 9, 2014: The patient returned for a one month follow-up showing excellent gingival health and no signs of clinical disease. The prosthodontist was monitoring the stability for a slight period longer before definitive restoration.

January 9, 2015: At the 6 month recall examination visit the patient presented without symptoms and no signs or recurrent endodontic pathosis. The periodontal tissues appeared be healthy with normal sulcular probing depths. The restoration of both teeth #’s 8 and 9 had been completed a few months earlier and the patient was very satisfied with the esthetics.

The currently planned recall exam schedule is June, 2015, and presuming the findings are unremarkable, then June 2016, and then a five year post-treatment recall examination with a limited field CBCT (June, 2019).

Key Learning Points:

1. Retreating previously performed endodontic procedures often results in mid-treatment surprise complexities.

2. Patients should be prepared for new decision points at the initial examination before treatment.

3. Long term provisionalization is a prudent way to insure an early failure will not compromise the definitive restoration.

4. Apically propagated root fractures are a common complexity found with microscope inspection of roots having posts and significant build-ups. Direct line endodontic access is important for discovery of complications in the apical third of roots.

5. Biodentine offers favorable strength, sealing, and biocompatibility features for use in severally compromised roots requiring a large volume of filling material. In smaller irregular areas requiring “flow” a bioceramic material such as Endosequence would be more suitable.

6. Micropreparation of cracks with an ultrasonic file minimizes critical root dentin removal and effectively cleans crypts.

7. Thoughtfully scheduling phased recall exams customized to the unique complexity treated not only allows immediate correction of any noticeable problems but also educates the clinician about outcome “cause and effect” of a myriad of complex clinical complications.