Variations in stroke rate and loading using hand sonic or ultrasonic instrumentation

Area of Science:

• Biomaterials and Dental Engineering
• Endodontic Instrumentation Mechanics

Background:

• Root canal preparation techniques significantly influence procedural outcomes.
• Understanding the biomechanics of hand, sonic, and ultrasonic instrumentation is crucial for effective endodontic treatment.

Purpose of the Study:

• To develop and utilize an in vitro model system to quantify stroke rate and canal wall loading during different endodontic instrumentation techniques.
• To compare the biomechanical parameters of hand, sonic, and ultrasonic instrumentation in a simulated clinical setting.

Main Methods:

• An in vitro model system was created using a mandibular molar tooth mounted on a strain gauge connected to a computer.
• Ten clinicians performed instrumentation of the distal canal using various file sizes with hand, sonic, and ultrasonic systems.
• Stroke rates and applied loads were measured and analyzed for each instrumentation technique and file size.

Main Results:

• Stroke rates were significantly slower for hand instrumentation compared to sonic and ultrasonic methods (p < 0.01).
• Canal wall loading increased with larger file sizes, significantly for hand (p < 0.01) and sonic (p < 0.05) instrumentation.
• No significant difference in stroke rates was observed between different file sizes within the same generator type (p > 0.05).

Conclusions:

• Sonic and ultrasonic instrumentation techniques offer significantly higher stroke rates compared to traditional hand instrumentation.
• File size impacts canal wall loading, with hand and sonic methods showing significant increases, unlike ultrasonic methods.
• The developed in vitro model provides valuable biomechanical data for evaluating endodontic instrumentation efficiency and safety.