Cauterization of Narrow Root Canals Untouched by Instruments by High-Frequency Current

Area of Science:

• Endodontics
• Biomaterials Science
• Electrical Engineering

Background:

• Mechanical cleaning of root canals has limitations in sterilizing biofilms in uninstrumented areas.
• Joule heating from electrical conduction in narrow root canals offers a potential sterilization method.
• Understanding the effect of electrical current on root canal walls is crucial for developing new endodontic treatments.

Purpose of the Study:

• To investigate the effect of high-frequency electric current on the wall of simulated narrow root canals.
• To evaluate the potential of electrical conduction for sterilizing uninstrumented root canal areas.
• To assess the impact of electrical conduction parameters and irrigants on root canal wall morphology and composition.

Main Methods:

• Simulated root canals (0.1 mm diameter) in dentine blocks were prepared and decalcified.
• Root canals were filled with saline or sodium hypochlorite (NaClO).
• High-frequency electric current (150-225 V, 520 kHz) was applied for varying durations (0-5 s), followed by SEM and EDS analysis.

Main Results:

• Increased conduction time and use of NaClO led to a decreased proportion of flat decalcified surfaces.
• SEM revealed significant increases in dentinal tubule visibility and lava-like morphology (p < 0.01).
• EDS analysis showed significant decreases in carbon and oxygen and increases in calcium (p < 0.01).

Conclusions:

• Filling uninstrumented root canals with NaClO and applying electrical conduction for 5 seconds can incinerate and eliminate organic material on the root canal wall.
• High-frequency electrical current application shows promise for treating persistent apical periodontitis.
• This technique may offer a novel approach to complete root canal sterilization.