Cyclic fatigue of instruments for endodontic glide path.

Area of Science:

• Endodontics
• Dental Materials Science
• Biomaterials Engineering

Background:

• Creating a smooth endodontic glide path is crucial for safe canal preparation.
• Nickel-titanium (NiTi) rotary instruments are commonly used, but alternatives are explored.
• Stainless steel (SS) K-files in reciprocating motion offer a potential alternative.

Purpose of the Study:

• To compare the cyclic fatigue resistance of SS K-files in reciprocating motion versus NiTi rotary instruments.
• To evaluate the durability of SS K-files for mechanical glide path creation in curved canals.

Main Methods:

• Ten size 15 SS K-files used with an M4 reciprocating handpiece were tested.
• Ten size 16, 0.02 taper NiTi rotary PathFiles were tested.
• Instruments were subjected to cyclic fatigue testing in artificial curved canals, recording time to fracture.

Main Results:

• SS K-files in the M4 handpiece exhibited a mean time to failure of 1049 seconds (±24.8).
• NiTi rotary PathFiles had a mean time to failure of 464 seconds (±40.4).
• A statistically significant difference (p=0.033) showed SS K-files had greater cyclic fatigue resistance.

Conclusions:

• SS 15 K-files used with a reciprocating motion demonstrated significantly higher cyclic fatigue resistance compared to NiTi rotary PathFiles.
• The use of small-sized SS files in a reciprocating motion is a rational and potentially more durable option for creating mechanical endodontic glide paths in curved root canals.