A comparison of mesial molar root canal preparations using two engine-driven instruments and the balanced-force...

Area of Science:

• Endodontics
• Dental Materials Science
• Biomaterials Engineering

Background:

• Root canal preparation aims to clean and shape the canal space.
• Engine-driven nickel-titanium (NiTi) rotary instruments offer potential advantages over traditional hand files.
• Understanding canal transportation is crucial for maintaining root canal anatomy and preventing procedural errors.

Purpose of the Study:

• To compare the shaping ability of two engine-driven NiTi rotary systems (ProFile .04 taper, Pow-R) against hand files (Flex-R) in simulated curved root canals.
• To evaluate canal transportation and preparation time in slight and moderately curved canals.

Main Methods:

• Seventy-two extracted human mandibular molars with mesial roots were used.
• Roots were divided into three groups: ProFile .04 taper, Pow-R rotary, and Flex-R hand filing.
• Roots were cross-sectioned, imaged, and computer-analyzed to assess canal shape and transportation before and after instrumentation.

Main Results:

• At the middle third, most systems tended to cut towards the mesial side, except Pow-R which cut towards the distal (danger zone).
• In the apical third, Flex-R and ProFile showed increased mesial transportation in more curved canals.
• Flex-R exhibited greater lingual cutting than Pow-R in moderately curved canals at the middle third. Hand filing was faster in some instances.

Conclusions:

• Engine-driven NiTi rotary systems can lead to significant canal transportation, especially in curved canals.
• The choice of instrument system impacts the final canal shape and potential for procedural errors.
• Hand filing may offer a faster preparation time in certain scenarios.