Management of a tooth with a large radiolucency

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Dr. Nishan Odabashian discusses treatment of teeth with failing previous root canal treatment exhibiting large radiographic lucencies


A healthy 53-year-old male presented to our office on May 9, 2011, after being referred by a friend who was treated at our office. He was advised that he needed to have tooth No. 19 removed, and the extraction site grafted with bone and soft tissue.

After 4 months, he needed to have the area evaluated for implant placement. Otherwise, his options were to place a 4-unit fixed partial denture (FPD), or a removable partial denture (RPD). The implant route was cost-prohibitive for him, and he was desperately seeking someone who would try to save his tooth.

Clinical and Radiographic Examination

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Clinical findings: The 

patient had a 3-unit FPD on the left mandibular molar area extending from the second premolar, mesially, to the second molar (18-20) distally. A slight swelling was present, buccal to tooth No. 18, and the probing depths were surprisingly within normal limits, even when probed under anesthesia. Patient reported pain on chewing, percussion, and palpation.

Radiographic findings: Periapical and bitewing radiographs were taken. (Today, a CBCT scan would also be taken as part of the radiographic examination.) The preoperative PA radiograph showed a 3-unit prcelain fused to metal (PFM) FPD extending from tooth No.18 to 

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tooth No. 20. Tooth No. 18 had previously treated root canals with a cast metal post extending into the distal root, while tooth No. 20 did not have previous endodontic treatment. A large (~15 mm in diameter, see PA 

radiograph) PA lucency was present on the mesial root of tooth No. 18, extending midway to tooth No. 20, extending from the osseous crest to the level of the root apex of tooth No. 18.

Medical history

Non-contributory. Patient was prescribed amoxicillin 500 mg TID for 2 days by his general dentist.


  • Pulpal: Previously treated pulp
  • Periapical: Symptomatic periapical abscess

Differential diagnosis

  • Lesion of endodontic origin
  • PA cyst
  • Lateral periodontal cyst
  • Odontogenic keratocyst
  • Immediate treatment plan
  • Incision and drainage (I and D)
  • Initiate retreatment, and based on results, send for biopsy or continue with endodontic retreatment.

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Treatment was initiated with an I and D of the buccal swelling. The patient’s antibiotic regimen was changed to clindamycin 300 mg, sig 1 tab TID for 5 days. Retreatment followed by accessing the distal abutment of the 3-unit FPD. The cast post and existing gutta percha were removed. The canals were cleaned, shaped, and dressed with calcium hydroxide for a total period of 7 months. In the interim, there were three calcium hydroxide changes after the internal aspect of the tooth was cleaned — first at 1 month, second at 3 months, and then at 5 months. The internal aspect of the crown was cleaned, and restored using Encore® paste (see photo). At the end of the endodontic treatment, the 3-unit FPD was removed, and a temporary bridge was made using the original impression taken at the first appointment. The patient was referred back to the referring doctor with a temporary bridge and the lucency considerably reduced. Recall radiographs were taken at 3 months, 6 months, 1 year, 2 years, and very recently 3 years from the initiation of treatment. We will continue to recall patient every year for an indefinite period of time.

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Management of teeth with previous root canal treatment that is failing requires more than just performing endodontic retreatment or surgery. The treating clinician must evaluate the cause of failure. These causes can range from being endodontic, restorative, periodontic, occlusion, patient’s habit (i.e. tongue ring), trauma, etc. Often, teeth with prior root canal treatment that present with large radiolucencies require a commitment from the patient and the treating doctor. Without this understanding and firm commitment to see the treatment through, it is not possible to see outcomes such as the one presented here. The endodontist has a responsibility of not only performing the endodontic retreatment, but to also make sure that the restorative treatment will be appropriate in order to ensure a long-term success. One of the ways that the endodontist can control a more positive outcome of his treatment is to place the core buildup after completing the endodontic treatment, under rubber dam isolation. This will eliminate one of the links that may lead to failure of the treatment. Another way that the endodontist can control a possible problem with his/her treatment is paying close attention to the occlusion of the patient during the recall appointment after placement of the final restoration. As a case in point, at the 3-month recall appointment, this patient returned with a 3-unit FPD placed. Upon radiographic examination, a widened PDL space was noted on the mesial aspect of tooth No. 18. This was not present at the postoperative radiograph. An occlusal evaluation revealed a working side interference in lateral excursive movement. The interference was adjusted, and the patient showed a normal PDL space at the next recall appointment.

Obviously, treatments such as these require much more time than a single appointment that is needed for a vital molar tooth. However, the satisfaction of saving such teeth and seeing what is possible with meticulous coordinated dental treatment is immeasurable. A tooth such as this in no way can satisfactorily financially compensate us for the time that is expended on it. However, not everything is measured by money! As the MasterCard® commercial says, these are “priceless.”


I thought this case study would serve a few purposes: 

  • To show that teeth with large radiolucencies can be treated/retreated endodontically
  • To demonstrate that large amount of bone can be regenerated without any bone grafts
  • That it takes a committed patient and clinician to see cases such as this through to successful treatment
  • That teeth that would otherwise be extracted can be saved
  • To expand our hypothesis space when treatment planning a failing root canal treated tooth.

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