Retrospective Assessment of Endodontically Treated Teeth Replaced by Dental Implants.

[INTRODUCTION] This study investigated endodontically treated teeth that were replaced by dental implants at the University of North Carolina (UNC) at Chapel Hill School of Dentistry. The primary objective of this study was to determine the reasons leading to the extraction of endodontically treated teeth and their subsequent replacement with dental implants. The secondary objective was to evaluate the proportion of these teeth that, according to experienced endodontists, could have been preserved.

[METHODS] The UNC-Chapel Hill's dental electronic health records between 2004 and 2019 were probed for implant placement that replaced root canal-treated teeth. Preextraction radiographs and clinical charts were examined to ascertain the primary reason related to the extraction and to compile a profile for each case. In cases in which endodontic failure was the primary reason for extraction, radiographs and clinical findings were evaluated by 2experienced endodontists to assess potential treatment options.

[RESULTS] Between 2004 and 2019, 29.3% (1564 of 5229) of teeth replaced by dental implants at UNC School of Dentistry had undergone root canal treatment, with the mandibular first molar being the most commonly replaced tooth. The leading reasons for extraction were recurrent caries associated with defective restoration (26.6%), fracture of coronal structure (21.5%), vertical root fracture (20.9%), compromised periodontal condition (13.8%), and endodontic failure (2.4%). Two experienced endodontists evaluated extractions due to endodontic failure and concluded that 61.7% of them could have been candidates for endodontic retreatment.

[CONCLUSION] Substantial loss of tooth structure was the leading cause of extraction of root canal-treated teeth, followed by vertical root fracture and periodontal disease. Although endodontic failure constituted a minor portion of the reasons for extraction, a considerable number of teeth were extracted due to vertical root fractures following root canal treatment. A significant proportion of the extracted teeth due to endodontic failure could have been considered as potential candidates for endodontic retreatment.