A retrospective study of initial root canal treatment failure in maxillary premolars via using cone-beam computed tomography.

BACKGROUND: This case-series study examined canal morphology and common factors for endodontic failure in maxillary first and second premolars that were referred for retreatment owing to clinical symptoms or radiographic signs. METHODS: Records were retrospectively searched using Current Dental Terminology codes to identify maxillary first and second premolars with endodontic failure. Periapical and cone-beam computed tomographic images were examined to determine Vertucci classifications and suspected factors related to treatment failure. RESULTS: A total of 235 teeth from 213 patients were included for evaluation. The following Vertucci classification of canal configurations were observed for maxillary first and second premolars: type I (1-1) (4.6% and 32.0%, respectively), type II (2-1) (15.9% and 27.9%, respectively), type III (2-2) (76.1% and 36.1%, respectively), type IV (1-2) (0% and 2%, respectively), and type V (3) (3.4% and 2%, respectively). More treatment failures were noticed in maxillary second premolars than first premolars and in females than in males. The 4 most common factors related to failure were inadequate filling, restorative failure, vertical root fracture, and missed canals. Missed canals were more frequently identified in maxillary second premolars (21.8%) than first premolars (11.4%) (P = .044). CONCLUSIONS: Multiple factors are associated with primary root canal treatment failures in maxillary premolars. Variations in canal morphology appear to be underappreciated in maxillary second premolars. PRACTICAL IMPLICATIONS: Maxillary second premolars have more complicated canal configurations than first premolars. Besides adequate filling, clinicians should give extra attention to anatomic variability in second premolars owing to higher failure incidence.

Prevalence of Nonendodontic Diagnoses in Periapical Biopsies: A 6-year Institutional Experience.

INTRODUCTION: The purpose of this study was to identify nonendodontic periapical lesions (NPLs) mimicking endodontic pathosis, which are most frequently encountered by clinicians. METHODS: A retrospective study was conducted on biopsies obtained from 2015-2020 at Texas A&M College of Dentistry's oral pathology laboratory. The online database was screened for cases submitted as suspected endodontic pathology using specific key words. Histologic diagnoses were collected to determine the prevalence of NPLs that were originally thought to be of endodontic origin. The frequency and percentage of endodontic pathology and NPLs were documented. RESULTS: Among 6704 biopsies clinically diagnosed as endodontic lesions, 190 (2.8%) were histopathologically diagnosed as NPLs. The most frequent NPLs were odontogenic keratocytes' (n = 70, 36.8%), cemento-osseous dysplasia (n = 27, 14.2%), and dentigerous cysts (n = 22, 11.6%). Of all NPLs, 3.7% were malignant neoplasms, with the most common diagnosis being squamous cell carcinoma. Of 6514 endodontic histologic diagnoses, the prevalence of periapical granulomas and cysts was 60.2% (n = 3924) and 39.1% (n = 2549), respectively. CONCLUSIONS: Although most endodontic submissions are likely to be histologically diagnosed as periapical granulomas or cysts, the clinician should be aware that a small portion of these lesions may be nonendodontic in origin and possibly neoplastic in nature. Histopathologic evaluation of biopsied specimens is critical to achieve a proper diagnosis to ensure the appropriate management of patients.