Evaluation of imaging protocols for detecting tooth ankylosis using different CBCT devices: an in vitro study.

BACKGROUND

To compare the diagnostic accuracy of CBCT images acquired with different imaging protocols for detecting tooth ankylosis.

METHODS

Thirty extracted permanent teeth (20 single-rooted, 10 three-rooted) were prepared; ankylosis was simulated in 20 by selectively removing Teflon from roots previously coated to mimic the periodontal ligament. Samples were embedded in stone plaster and imaged using 4 protocols on 2 CBCT units. CBCT images were primarily evaluated by a blinded radiologist (present/absent). Micro-CT was performed on 20% of specimens to verify the model. Agreement and accuracy metrics (Fleiss/Cohen κ, sensitivity, specificity, PPV, NPV) were calculated.

RESULTS

Protocol 2 (0.25 mm voxel) showed the most favorable performance (κ = 0.113; sensitivity 71.4%; PPV 52.6%; NPV 60%). Protocol 3 (0.35 mm voxel) performed worst (κ = -0.104; sensitivity 53.8%; PPV 43.8%; NPV 45.5%). Except for Protocol 3, sensitivity was high (≥71.4%) while specificity remained low (35.7%-42.9%).

LIMITATIONS: The study has its own limits. Different imaging protocols using in clinical practice to detect ankylosis can be investigated as well to provide different approaches assessing ankylosis.

CONCLUSION

CBCT demonstrated high sensitivity but low specificity for ankylosis detection, indicating a propensity for false positives. Smaller voxel sizes (0.25-0.30 mm) improved detection, whereas 0.35 mm was least reliable.