Advancing endodontic imaging: a high-resolution comparison between CBCT and micro-CT in the danger zone

Area of Science:

• Dental Imaging
• Radiology
• Endodontics

Background:

• Accurate measurement of submillimetric dentin thickness is crucial in endodontic diagnosis and treatment planning.
• The 'danger zone' (DZ) in mandibular molars requires precise assessment due to its proximity to vital structures.

Purpose of the Study:

• To evaluate the accuracy of various cone-beam computed tomography (CBCT) protocols for measuring submillimetric dentin thickness in the mandibular molar danger zone (DZ).
• To compare CBCT accuracy against micro-computed tomography (micro-CT) as the gold standard.

Main Methods:

• Fifty-one extracted mandibular molars were scanned using micro-CT and two CBCT devices with Standard, High Fidelity, and High Resolution (HIRE) protocols.
• Three-dimensional image registration was performed to measure dentin thickness in the DZ of mesial canals.

Main Results:

• All CBCT protocols significantly underestimated dentin thickness compared to micro-CT (p < 0.05), with discrepancies from 4.5% to 8.6%.
• The mesiolingual canal showed greater underestimation.
• The HIRE protocol (0.125 mm voxel size) demonstrated the smallest discrepancy, while the i-CAT protocol showed the largest.

Conclusions:

• CBCT systematically underestimates dentin thickness in the mandibular molar DZ.
• CBCT is not metrically equivalent to micro-CT for submillimetric measurements.
• Measurement accuracy is influenced by acquisition parameters beyond just voxel size.