(PR070) Balancing Efficacy and Risk of Extrusion with Laser-Activated Irrigation in Root Canal Systems: A Cadaver-Based Study

Introduction: The goal of this study is to evaluate the incidence and volume of contrast medium extrusion when activated with a laser, and to compare it with other irrigation techniques. Additionally, the depth of penetration of the contrast medium into the canal was measured to assess the efficacy of each irrigation protocol in facilitating irrigant delivery closer to the apical foramen.

Methods: 16 cadaver mandibles containing 134 single-rooted teeth were prepared using conventional rotary instrumentation. Teeth were randomly assigned to 4 irrigation groups: side-vented needle; sonic irrigation; laser activation at the orifice; and laser activation at the middle third of the canal. Gastrografin, an iodinated contrast medium, was used to simulate irrigants. CBCT scans were obtained pre- and post-irrigation to assess the incidence, volume of extrusion, and the depth of irrigant penetration. Data were statistically analyzed using ANOVA and chi-squared tests.

Results: Laser activation at the middle third significantly improved irrigant penetration to the apical region compared to other techniques (p < 0.00001). Only one tooth in the group with laser activation at the middle third of the canal (n=34) showed extrusion (0.25 mm^³), while no extrusion occurred in the other groups.

Conclusion: Laser-activated irrigation at the middle third of the canal enhances apical irrigation penetration, though care must be taken to avoid extrusion. This cadaver-based model, combined with CBCT, provides a clinically relevant assessment of irrigant behavior during endodontic treatment.