Available online 27 April 2024, 105983

One hundred and sixty-three two-rooted mandibular molars were scanned using micro-CT

The roots apical 3-mm were classified according to their aspect ratio and anatomy

Mesial roots with higher apical aspect ratios showed more main and accessory canals

3D assessment revealed higher proportions of apical deltas in higher aspect ratios

Distal root with higher aspect ratios had higher number of canals at all axial levels

This study aimed to investigate the relationship between the aspect ratios of mandibular molar roots at the apical 3-mm level and their root canal complexity.

This study used micro-CT imaging to analyze 163 two-rooted mandibular molars. The aspect ratios of the roots at the apical 3-mm level were categorized as "<2.75" or "≥2.75" (mesial) and "<1.75" or "≥1.75" (distal). A two-dimensional (2D) analysis focused on four apical axial cross-section levels to determine the presence of main and accessory canals and isthmus. Additionally, a three-dimensional (3D) assessment of the apical 4-mm of both roots examined main and accessory canals, apical foramina, apical deltas, and middle mesial canals.

Mesial roots with aspect ratios ≥2.75 showed a higher number of main canals at all levels compared to those with aspect ratios <2.75 at the 3-mm level. Additionally, the ≥2.75 group exhibited more accessory canals and a higher average number of accessory canals. The 3D assessment confirmed significantly more accessory canals and apical foramina in the ≥2.75 group. The prevalence of roots with apical deltas was nearly double in the ≥2.75 group, and middle mesial canals were exclusively found in this group. In the distal root, the ≥1.75 group showed a significantly higher number of main canals at all axial levels. No significant differences were observed between groups in terms of accessory canals, apical foramina, or deltas.

A higher root aspect ratio is related to higher anatomical complexity.

Anatomy

endodontics

mandibular molar

micro-CT

root canal therapy

surgery

© 2024 The Authors. Published by Elsevier Ltd.