Instrumentation of curved root canals: a comparison study

Area of Science:

• Endodontics
• Dental Materials Science

Background:

• Root canal instrumentation aims to clean and shape the root canal system.
• Maintaining the natural canal anatomy, particularly curvature, is crucial for successful endodontic treatment.
• Rotary file systems offer potential advantages in efficiency and control during preparation.

Purpose of the Study:

• To compare the efficacy of three different rotary nickel-titanium files (Flex-R, Flex-O, K-Flex) in maintaining canal curvature.
• To evaluate the impact of a circumferential filing technique on root canal anatomy preservation.

Main Methods:

• Thirty extracted human molars with initial curvatures of at least 18 degrees were selected.
• Buccal canals of maxillary molars and mesial canals of mandibular molars were instrumented using a circumferential filing technique with Flex-R, Flex-O, or K-Flex files.
• Canal curvature was measured before and after instrumentation using digital radiography.
• Statistical analysis was performed to compare changes in canal curvature.

Main Results:

• All three tested rotary file systems demonstrated a high degree of accuracy in maintaining the original canal curvature.
• No statistically significant difference was observed between the Flex-R, Flex-O, and K-Flex files regarding their ability to preserve canal anatomy.
• The circumferential filing technique, when used with these rotary instruments, effectively preserved the canal's angular and geometric integrity.

Conclusions:

• Flex-R, Flex-O, and K-Flex rotary files are effective in preserving root canal curvature during instrumentation.
• The choice of file among these three does not significantly impact the maintenance of canal anatomy.
• These findings support the use of these rotary systems for predictable root canal preparation in curved canals.