Interim Endodontic Therapy for Alveolar Socket Bone Regeneration of Infected Hopeless Teeth Prior to Implant Therapy
The immediate placement of implants in the fresh extraction sockets of infected teeth with periradicular and periapical lesions is contraindicated because of both the infection and the loss of architecture required for proper implant placement. There are 4 approaches for implant replacement of a hopeless tooth with lesions: (1) extraction and delayed implant placement; (2) extraction, debridement, guided bone regeneration (GBR), guided tissue regeneration (GTR), and delayed implant placement; (3) extraction, intrasocket debridement, and immediate implant placement; or (4) extraction, debridement, GBR, GTR, and simultaneous implant placement. The extraction of such hopeless teeth often results in large bone and soft tissue defects that are difficult to repair. This article introduces an alternative approach: interim endodontic implant site preparation, defined as a transitional, surgical, or nonsurgical endodontic treatment to regenerate the hopeless tooth bone defects and prepare the site for proper implant placement. This article describes 3 distinct interim endodontic protocols used to manage 5 patients, all of whom had severely infected hopeless teeth with large lesions and were treatment planned for implant replacement: the first, interim nonsurgical endodontic treatment to restore the normal anatomy of the infected hopeless tooth; the second, interim surgical endodontics on the hopeless tooth with preexisting endodontic treatment to regenerate apical bone for primary implant stability, thus avoiding the involvement of the maxillary sinus and other critical anatomic structures; and the third, interim surgical endodontics on the hopeless tooth with preexisting endodontic treatment to confine the size of the osseous defect and simplify the GBR and GTR procedures. The outcome of interim endodontic treatment on these 5 patients demonstrated that tooth extraction would have been a less predictable approach. The interim treatment changed the overall direction of the patients' dental care. When treated, these hopeless teeth served many preventive, biologic, and esthetic functions. The infections of the alveolar sockets were eliminated, the alveolar bone defects were repaired through normal bone regeneration, and sockets anatomies were maintained or restored. Furthermore, the patients were spared maxillary sinus surgery and the possible complications resulting from major GBR and GTR procedures. In summary, the interim treatment facilitated tooth extraction and immediate implant placement.Abstract

Figure 1. Preoperative radiograph of hopeless tooth no. 14 as presented by the patient with post cavity preparation and pulp chamber floor perforation. Figure 2. Clinical view of hopeless tooth no. 14 with pulp chamber floor bur perforation. The tooth was previously endodontically treated and was being prepared for cast post restoration when the perforation occurred. Figure 3. A full-thickness buccal and palatal mucoperiosteal intrasulcular flap revealed a defect that involved the furcation and the entire palatal bone of tooth no. 14. Figure 4. For esthetic reasons, a provisional fixed partial denture (FPD) was constructed from the buccal roots of tooth nos. 12–14. Observe the radiolucency of the defect that became visible after the removal of the palatal root and defect debridement. Figure 5. After 1 year of interim surgical endodontic treatment, the provisional FPD was sectioned at the bicuspid level, the buccal roots were extracted. Observe the complete regeneration of the furcal and palatal bone. Figure 6. (A) An implant was placed in the furcal and palatal regenerated bone. A second implant was placed in the edentulous area of tooth no. 13. (B) The implants placed in tooth nos. 13 and 14. Observe the opacity of the regenerated area on tooth no. 14 in comparison to the radiographic radiolucency in Figure 4.

Figure 7. Preoperative radiograph of tooth no. 5 with root mid-third defect. The tooth also had 2–3 mm endodontic overfill. Observe the proximity to the maxillary sinus floor. Figure 8. Postoperative radiograph of tooth no. 5 following interim surgical endodontics via deep apicoectomy and apical gutta-percha cold burnishing. Note: No osteoconductive material was placed in the apical defect in order to monitor the bone regeneration. The defect was filled with radiolucent collagen wound dressing and covered with barrier membrane. Figure 9. Tooth no. 5, 1 year following interim surgical endodontics. Observe apical socket bone regeneration. Figure 10. The fresh extraction socket of tooth no 5. Observe the thickness of the regenerated apical bone separating the socket from the maxillary sinus and providing native bone for implant primary stability. Figure 11. Immediate implant replacement of tooth no. 5 with a SIS 12-mm Straumann Standard Plus implant. Figure 12. The implant restoration 9 months after immediate placement.

Figure 13. Preoperative radiograph of tooth no. 19 with periradicular and periapical defects. The tooth had history of emergency endodontic care. Figure 14. An occlusal view of tooth no. 19, which was considered hopeless due to tooth structure loss that extended into the subgingival lingual furcation area. The pulp chamber floor was severely damaged. Figure 15. Tooth no. 19 following interim nonsurgical endodontics. The tooth was restored via a composite intracoronal post build-up. Figure 16. Recall radiograph of tooth no. 19, 6 months following interim nonsurgical endodontics. Observe the complete defect bone regeneration.

Figure 17. Preoperative radiograph of hopeless tooth no. 30 with vertical root fracture and periradicular and periapical defect involving the entire mesial root. Figure 18. A full-thickness mucoperiosteal intrasulcular buccal and lingual flap revealed a buccolingual mesial root vertical fracture. Observe the loss of the mesiobuccal cortical plate and mesial interproximal bone. Figure 19. Once the mesial defect was debrided for hemorrhage control and visibility, the mesial root was sectioned buccolingually. Figure 20. The mesial root is completely sectioned and ready for removal. The coronal restoration was also modified to satisfy the requirements of proper restorative principles and oral hygiene care. Figure 21. The removal of the fractured root allowed access to debride the entire mesial socket. Care was exercised in debriding the apical side of the defect to avoid the inferior mandibular neurovascular bundle. Figure 22. The furcation area was modified and refinished to remove any dentinal spurs or rough surfaces and to allow proper oral hygiene care throughout the interim therapy period. The interproximal contacts were maintained and the restoration was removed out of occlusion.

Figure 23. Clinical view of the defect following debridement and restoration modification. The site is ready for a radiograph prior to defect augmentation. Figure 24. Preaugmentation radiograph to evaluate the root amputation site and the debridement procedures. Observe the metal shavings that accumulated and were removed before augmentation and surgical closure (March 2008). Figure 25. Radiograph of the fresh extraction socket of the distal root of no. 30 and immediate implant placement, 5 months after interim surgical endodontics (July 2008). Figure 26. Recall radiograph of no. 30 area, 1 year following interim surgical endodontics, and 8 months after implant placement. Figure 27. Radiograph of the implant final restoration. Figure 28. Clinical photograph of the implant final restoration.

Figure 29. Preoperative radiograph of endodontic failure on tooth nos. 8 and 9 with large periradicular and periapical osseous defects. The teeth were considered structurally hopeless due to crack lines on the labial root surface of both teeth. Figure 30. The restorations were removed to evaluate the underlying tooth structure, and replaced with esthetic resin restorations. Interim surgical endodontics via deep apicoectomy was performed. The debrided surgical defect encompassed the whole apical and midline interproximal bone of both teeth. Note: The debrided defect was packed with collagen wound dressing and covered with barrier membrane in order to promote and monitor the healing process. Figure 31. Recall radiograph 6 months following interim surgical endodontics. Observe the significant regeneration of native bone sufficient for implant primary stability and protection of the incisive foramen and the nasal cavity floor.
Contributor Notes
Prince AbdulRahman Advanced Dental Institute, Riyadh, Kingdom of Saudi Arabia; Department of Endodontics, University of Southern California - School of Dentistry, Los Angeles, Calif.