A Novel Ultrasonic Welding-Assisted Thermoplastic Root Canal Obturation Technique: An Ex Vivo Proof-of-Concept Study

To evaluate the effectiveness of an ultrasonic welding (USW)-assisted thermoplastic obturation technique for improving root canal sealing, void reduction, and lateral canal penetration.

A three-phase experimental approach was employed: (1) Customized gutta-percha points were developed, optimized to incorporate ultrasonic-responsive thermoplastic obturation cores; (2) in vitro testing was conducted using micro-computed tomography (CT) and infrared thermometry to assess lateral canal flow and thermal safety, respectively; and (3) an ultrasonic generator (28+ kHz), booster, and sonotrode were used to generate the heat required for obturation.

Compared with traditional methods, the USW technique demonstrated a mean void reduction of 62% (95% CI: 58%-66%, p < 0.001), significant lateral canal penetration, and maintained temperatures safely below 45°C. No microfractures were observed in the treated teeth.

The USW-assisted obturation technique facilitates and enhances root canal obturation, reduces voids, and maintains tooth structural integrity through precise energy application combined with improved flow mechanics.