CASE REPORT 2
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Figure 21. Preoperative radiograph showing periapical lesions. |
Figure 22. CT image showing an isthmus in mesial root. |
A 47-year-old man was referred for treatment of his right mandibular first molar. His referring dentist had once performed endodontic treatment on the tooth but didn’t achieve complete healing. The previous endodontic treatment had been accomplished a month before, and the access cavity had been sealed with Cavit G temporary cement (3M ESPE).
The patient had reported to have one episode of moderate pain and swelling associated with the tooth. The tooth was symptomatic and tender to percussion or biting with a sinus tract opening on the buccal mucosa area. He admitted that he had been under a lot of stress and had a clenching habit while working on the computer in his office, or even while lost in thought, daydreaming. Periodontal probings were 3 mm or less, with no mobility. Radiographs were taken for preoperative examinations (Figure 21), and the tooth was CT-scanned after the majority of root filling materials were removed from the root canals to obtain clear images. The CT images revealed that there were mesiobuccal and -lingual canals in the mesial root with an isthmus connecting them and each canal in the distobuccal and -lingual roots (Figure 22). There were periapical lesions associated with the mesial- and the distolingual roots. The distobuccal canal appeared to have been overprepared by approximately 40% to 50% on the serial cross-sectional CT images. The root fillings in all 4 canals seemed to occupy the canal space up to the termini. The periodontal ligament was within normal limits. The provisional diagnosis was radicular periodontitis developing with infection from the isthmus area and the distolingual canal. The referring dentist reported that the distolingual canal was severely infected, particularly around the orifices of those canals. Analysis of the occlusal relationship indicated normal occlusion, but occlusal wear was obvious on most of the posterior teeth that had dozens of shiny spots on the metal crowns and abrasion on occlusal cusps.
Retreatment
Retreatment started by isolating the tooth with a rubber dam. Gutta-percha filling material was removed with a BUC 1A ultrasonic tip and the TGR, and then the tooth was CT-scanned for more details. There was an isthmus found connecting the mesiobuccal and mesiolingual canals. The isthmus seemed to be responsible for the periapical lesion around the mesial root and was chemomechanically cleaned using a CPR-8 ultrasonic tip with 17% EDTA solution. The distolingual canal was relatively clean, but had some debris left over in the orifice area. All the canals were negotiated with a No. 10 K file to working length which was verified by a Root ZX apex locator and then prepared with GT rotary files. The canals were temporarily dressed with calcium hydroxide mixed with 2% chlorhexidine (CHX) to disinfect the canal system between the patient’s visits.
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Figure 23. Postoperative radiograph showing all the canals were properly obturated. |
Figure 24. Postoperative radiograph after 3 months. |
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Figure 25. Postoperative radiograph after 6 months. |
Figure 26. Postoperative radiograph after 18 months with widened periodontal ligaments. |
At his second visit, the distolingual canal was prepared with a No. 30/.10 GT file. However, a No. 70 K file dropped through the mesiobuccal, the mesiolingual, and the distobuccal canal termini, all of which were considered too large to obturate with gutta-percha fillings for complete sealing. All the canals were irrigated with 5.25% sodium hypochlorite solution refreshed every 5 minutes, and this process was repeated for 30 minutes. MTAD was used for final rinse of all the canals. The distolingual canal was then obturated with gutta-percha and pulp canal sealer using the System B heat source and was backfilled with the Obtura gun. The rest of the canals were subsequently obturated with gray ProRoot MTA, because warm vertical condensation with gutta-percha filling material was not good enough to seal the canals with large canal termini, especially in retreatment cases. A radiograph was taken to confirm the appropriate obturation into every canal (Figure 23). The tooth had been asymptomatic ever since the endodontic treatment was initiated. The patient was then placed on 3-month recall.
The 3-month review showed that almost half of the periapical lesion associated with the mesial root had been disappearing, and the majority of periapical lesions associated with the distal roots had resolved (Figure 24). There was no evidence of the periodontium breaking down. At his third visit, fiber posts were placed with dual-cured composite resin so that the tooth could be more resistant to fracture. The patient was then sent back to the referring dentist for restoration. The patient was advised to return 3 months after the restoration with a crown.
The 3-month post-restorative recall showed shrinkage of apical radiolucency of the mesial root (Figure 25), but the periodontal ligament seemed to be widened. He was advised that he should consult the referring dentist on his clenching habit. After all, the patient had returned 12 months after the previous visit with a chief complaint of the swelling on the buccal mucosa. Intraoral examination revealed a sinus tract opening on the inflamed mucosa. A radiograph was taken for examination and it showed that there were no obvious developing lesions associated with either the mesial root or distal ones except that the periodontal ligament around the apical half of the distobuccal root was widened (Figure 26). The patient reported the chewing sensitivity of the mandibular right first molar had gradually increased 7 months after the crown was placed on the tooth. Periodontal probings remained 3 mm or less with no mobility. The tooth was diagnosed with a symptomatic radicular periodontitis caused by potential vertical root fracture associated with his clenching habit. The patient was informed that surgical intervention was needed to determine whether the distal root had fractured or not. Treatment options including the possibility of extraction of the tooth were discussed, and the patient agreed to surgical endodontics.
Surgical Intervention
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Figure 27. Distobuccal root with a vertical fracture line. |
Figure 28. Distobuccal root end was separated from the coronal portion of the root. |
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Figure 29. Resected root surface on the micromirror showing MTA filling. |
Figure 30. Postoperative radiograph after the apicosurgery. |
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Figure 31. Postoperative radiograph 3 months after the apicosurgery. |
Figure 32. Postoperative radiograph 6 months after the apicosurgery showing complete healings of apical lesions. |
The surgical intervention under the microscope revealed that the tooth had a vertical fracture line on the distobuccal root coronally extending approximately 5 mm from the apex, and the fracture line ended about 5 mm below the level of crest bone (Figure 27). The patient was informed of the vertical root fracture during the surgical procedure, but he insisted on retaining the tooth because the root fracture was confined to the apical portion. Thereafter, the distobuccal root end was resected with a Lindemann bur where the fracture line terminated (Figure 28). The resected root surface was then stained with methylene blue to identify more anatomical details. There was no sign of further fracture line found on the resected root surface. The root end cavity was carefully inspected at high magnification under the microscope, and it was confirmed that the MTA filling was intact in the center of root end surface (Figure 29). A 17% EDTA solution was used to remove smear layer from the root end and rinsed with 2% CHX solution and a postoperative radiograph was taken (Figure 30). Abnormal cusps on the occlusal table that could interfere with smooth lateral and anterior movements were eliminated after the surgery. The patient returned 3 months later and the 3-month postoperative radiograph showed that the majority of the radiolucency associated with the distobuccal root had disappeared, but it was still visible on the radiograph (Figure 31). The patient was again placed on another 3-month recall. He returned 3 months later, and the 6-month postoperative radiograph finally showed the periodontal ligament was back to normal and the periapical lesions appeared to be healed (Figure 32).