Flat-oval root canal preparation with self-adjusting file instrument: a micro-computed tomography study

Area of Science:

• Endodontics
• Dental Materials Science
• Biomaterials

Background:

• Root canal preparation is crucial for endodontic treatment success.
• Flat-oval canals present unique challenges for instrumentation.
• Micro-computed tomography (micro-CT) offers precise 3D analysis of root canal morphology.

Purpose of the Study:

• To compare the efficacy of Self-Adjusting File (SAF) and rotary instrumentation in preparing flat-oval root canals.
• To quantitatively assess changes in canal volume, surface area, and geometry using micro-CT analysis.

Main Methods:

• Forty mandibular incisors with flat-oval canals were instrumented using either SAF or rotary files.
• Micro-CT scans were performed before and after instrumentation to evaluate canal preparation.
• Changes in canal volume, surface area, and cross-sectional geometry were statistically analyzed.

Main Results:

• No significant differences were found in overall canal area, perimeter, roundness, or diameters between SAF and rotary groups.
• SAF prepared a significantly higher percentage of root canal walls (92.0%) in the coronal third compared to rotary instruments (62.0%).
• SAF resulted in significantly greater increases in canal volume and area in the coronal third, with homogenous dentin removal.

Conclusions:

• SAF provides more effective and homogenous root canal preparation in the coronal third of flat-oval canals compared to rotary instrumentation.
• SAF ensures circumferential preparation, addressing untouched areas often left by rotary files.
• The apical preparation size achieved with SAF is comparable to a #40 rotary file with a 0.02 taper.