Changes in root canal geometry after preparation assessed by high-resolution computed tomography.

Area of Science:

• Endodontics
• Dental Materials Science
• Biomedical Imaging

Background:

• Root canal preparation is essential for endodontic treatment.
• Previous studies assessed canal preparation changes using destructive methods.
• Non-destructive imaging offers a novel approach to evaluate in-situ changes.

Purpose of the Study:

• To quantitatively assess root canal shape changes after preparation using different instruments.
• To compare the impact of K-Files, Lightspeed, and ProFile .04 rotary instruments on canal morphology.
• To investigate the influence of initial canal geometry on preparation-induced alterations.

Main Methods:

• Utilized high-resolution microcomputed tomography (micro-CT) for non-destructive scanning of 18 root canals in 6 maxillary molars.
• Scanned canals before and after preparation with K-Files, Lightspeed, or ProFile .04 rotary instruments.
• Calculated differences in canal surface area (deltaA) and volume (deltaV) using custom software and analyzed canal transportation.

Main Results:

• Significant variations in deltaV (0.64–2.86 mm³) and deltaA (0.72–9.66 mm²) were observed.
• Rotary instruments (ProFile and Lightspeed) resulted in slightly larger mean deltaV and deltaA compared to K-Files.
• Initial canal geometry demonstrated a greater influence on preparation outcomes than the instrumentation technique employed.

Conclusions:

• Preoperative root canal morphology is a critical factor influencing preparation-induced changes.
• While rotary instruments showed a trend towards greater canal alteration, initial anatomy played a more dominant role.
• Future studies comparing root canal instruments should account for baseline canal geometry for accurate assessment.