EFFECT OF PASSIVE ULTRASONIC ACTIVATION OF ETHYLENEDIAMINETETRAACETIC ACID ON CLOT-COVERED AREA AND FIBRIN NETWORK ORGANIZATION IN A REGENERATIVE ENDODONTIC MODEL

Objective: In regenerative endodontic procedures, the intracanal blood clot serves as a natural scaffold, and its interaction with conditioned dentin may influence the early regenerative environment. Although ethylenediaminetetraacetic acid (EDTA) is widely used for dentin conditioning, its calcium-chelating properties may affect clot formation. This ex vivo scanning electron microscopic study evaluated the effect of 17% EDTA, with or without passive ultrasonic irrigation (PUI), on ImageJ-derived clot-covered area and semiquantitative fibrin network organization in an immature root canal model.
Methods: Thirty extracted human maxillary central incisors were prepared and standardized to simulate immature open-apex canals. The specimens were assigned to three irrigation protocols: distilled water with syringe-and-needle irrigation (DW-SNI), 17% EDTA with syringe-and-needle irrigation (EDTA-SNI), and 17% EDTA with passive ultrasonic irrigation (EDTA-PUI). Fresh venous blood was applied to the intraradicular dentin surfaces, and clot formation was allowed for 10 minutes at 37°C. Scanning Electron Microscopy (SEM) images obtained from the coronal, middle, and apical thirds were analyzed using ImageJ to quantify fibrin/clot-covered area. Fibrin-like network organization was scored using a 4-point semiquantitative scale.
Results: ImageJ-derived fibrin/clot-covered area differed significantly among irrigation protocols (P = .022) and canal thirds (P = .001), whereas the interaction between irrigation protocol and canal third was not significant (P = .092). The EDTA-PUI group showed significantly greater fibrin/clot-covered area than the DW-SNI group in all canal thirds. In the middle third, EDTA-SNI also showed higher values than DW-SNI, and EDTA-PUI showed higher values than EDTA-SNI. Semiquantitative fibrin-like network organization scores did not differ significantly among irrigation protocols or canal thirds.
Conclusions: Within the limitations of this ex vivo study, passive ultrasonic activation of 17% EDTA was associated with greater ImageJ-derived clot-covered area without producing a detectable change in semiquantitative fibrin-like network organization. These findings suggest that EDTA-PUI may increase clot-associated surface coverage on intraradicular dentin under the tested conditions, but this should not be interpreted as direct evidence of improved fibrin density or clot homogeneity.