Single-Visit Endodontics Under Dental Operating Microscopy: A Retrospective Observational Study

Background Missed lingual canals in mandibular incisors may contribute to persistent post-endodontic pain and treatment failure. Identification and treatment of these untreated canals during retreatment may improve clinical outcomes. This retrospective observational study aimed to evaluate the occurrence of previously untreated lingual canals in symptomatic, previously treated mandibular incisors and to assess symptom resolution following single-visit nonsurgical retreatment. Materials and methods Clinical and radiographic records of 129 previously treated single-rooted mandibular incisors were screened. Thirty symptomatic mandibular incisors from 24 patients meeting the inclusion criteria underwent single-visit nonsurgical retreatment. Existing access cavities were refined with a ribbon-shaped lingual extension to facilitate canal exploration. Canal detection was initially performed under unaided vision and subsequently under dental operating microscope (DOM)-assisted magnification when an additional canal could not be identified. Previously untreated lingual canals were treated during the same visit. Pain intensity was recorded preoperatively and at 6 hours, 24 hours, 48 hours, and 7 days postoperatively using the modified 100mm visual analog scale. Canal detection frequencies and postoperative pain outcomes were summarized descriptively. Results Among the 129 screened teeth, 99 (76.7%) teeth exhibited a single-canal configuration, while canal configurations involving two canals were identified in 30 (23.3%) teeth. Previously missed lingual canals were identified in all 30 symptomatic mandibular incisors included in the study. Thirteen (43.3%) canals were detected during initial exploration under unaided vision, while 17 (56.7%) canals were identified only after subsequent DOM-assisted evaluation. Pain intensity decreased following retreatment, with complete or near-complete symptom resolution observed by the seventh postoperative day. Conclusion Previously untreated lingual canals were frequently identified in symptomatic mandibular incisors requiring retreatment. Single-visit nonsurgical retreatment addressing these untreated canals was associated with a substantial resolution of pre-existing symptoms. The combination of access cavity refinement and sequential unaided and DOM-assisted examination facilitated identification of additional lingual canals during retreatment.