Shaping ability of two nickel-titanium instruments activated by continuous rotation or adaptive motion: a...

Area of Science:

• Endodontics
• Dental Materials Science

Background:

• Root canal preparation in curved canals presents challenges in maintaining canal anatomy.
• Novel nickel-titanium (NiTi) file systems and kinematics aim to improve shaping efficiency and safety.

Purpose of the Study:

• To compare the shaping ability of Twisted File Adaptive (TFA) and Mtwo NiTi files in severely curved mandibular molars.
• To evaluate the influence of continuous rotation versus adaptive motion on canal preparation outcomes.

Main Methods:

• Thirty-two mandibular molars with severely curved mesial canals were prepared using TFA and Mtwo files.
• Files were activated by either continuous rotation or adaptive motion.
• Micro-computed tomography was used to assess canal volume, surface area, transportation, and centering ability.

Main Results:

• TFA files in continuous rotation resulted in less increase in volume and surface area compared to other groups.
• TFA files exhibited significantly less canal transportation and better centering ability than Mtwo files.
• Adaptive motion improved centering ratio compared to continuous rotation for both file types, particularly in coronal and middle thirds.

Conclusions:

• TFA files demonstrated superior shaping ability in the coronal and middle thirds of curved root canals compared to Mtwo files.
• Adaptive motion enhanced centering ability more than continuous rotation, especially in the coronal and middle thirds.
• No significant differences in shaping ability were observed in the apical third among the tested file systems and kinematics.