Depth-Resolved OCT of Root Canal Walls After Diode-Laser Irradiation: A Descriptive Ex Vivo Study Following a...

Background/Objectives: Diode lasers are used as adjuncts for endodontic disinfection, but their depth-resolved effects on root dentin are insufficiently described. This ex vivo study used optical coherence tomography (OCT) to qualitatively document laser-related morphological signatures on canal walls. Methods: Palatal roots from extracted maxillary first molars were standardized and hemisectioned to create specimens allocated to a conventional diode-laser protocol, a higher-power protocol, or control. A 940-nm diode laser with endodontic tips was applied per group. Swept-source OCT acquired serial B-scans along the root length. Two endodontists reviewed images for thermally induced morphological alterations (TIMAs). Reporting is descriptive. Results: OCT revealed laser-related hyper-reflective linear/radial signatures extending from the canal lumen toward the external root surface in laser-treated specimens. Qualitatively, signatures appeared more conspicuous and extended deeper with the higher-power protocol than with the conventional protocol. Findings were most evident in the coronal/middle thirds. Control specimens served to contextualize background appearances from preparation and sectioning. Representative B-scans illustrate typical patterns. The novelty of the present study results from the identification of areas of morphological alteration through the OCT examination of the walls of the root canals. Conclusions: Depth-resolved OCT can visualize dentinal alterations associated with diode-laser irradiation in an ex vivo model. These observations support careful parameter selection and motivate in situ studies with concurrent temperature monitoring and histologic correlation.