Real-time torque behavior of reciprocating nickel-titanium instruments using different irrigating solutions

Area of Science:

• Endodontics
• Dental Materials Science
• Biomaterials Engineering

Background:

• Reciprocating nickel-titanium instruments are used in root canal preparation.
• Mechanical stress during preparation can compromise instrument safety.
• The influence of irrigating solutions on operative torque is not well understood.

Purpose of the Study:

• To investigate the impact of different irrigating solutions on torque during root canal shaping.
• To compare torque generation across various reciprocating single-file systems.
• To analyze the interaction between irrigant type and file system on torque.

Main Methods:

• Extracted human mandibular premolars with oval canals were used.
• Three reciprocating file systems were tested with sodium hypochlorite, ethylenediaminetetraacetic acid, or saline.
• Torque-controlled motors recorded real-time operative torque and preparation time.

Main Results:

• Irrigating solutions alone did not significantly affect torque or preparation time.
• A significant interaction between file system and irrigant type was observed.
• The T-Endo MUST system generated significantly higher mean and peak torque compared to other instruments.

Conclusions:

• Instrument design characteristics appear to be more critical than irrigating solutions in influencing mechanical stress.
• The specific combination of file system and irrigant affects torque response.
• Understanding these interactions is crucial for optimizing root canal preparation safety and efficiency.