Assessing the accuracy of two posterior tooth-size discrepancy prediction methods based on virtual occlusal setups

Area of Science:

• Orthodontics
• Dental Morphology
• Biotechnology

Background:

• Accurate assessment of interarch tooth-size discrepancies (ITSDs) is crucial for successful orthodontic treatment planning.
• Traditional analyses like Bolton and Johnson/Bailey (JB) are used to estimate ITSDs, but their clinical accuracy in posterior regions requires further validation.

Purpose of the Study:

• To evaluate the accuracy of the Bolton and JB analyses in identifying clinically significant posterior tooth-size discrepancies.
• To compare the performance of Bolton and JB analyses using virtual occlusal setups derived from cone-beam computed tomography (CBCT) data.

Main Methods:

• Virtual posterior occlusal setups were constructed from CBCT data of 30 patients.
• Observed cusp-embrasure discrepancies were compared to ITSDs calculated using Bolton and JB posterior analyses.
• Clinical significance was defined as >1 mm discrepancy, following American Board of Orthodontics methodology.

Main Results:

• The JB analysis demonstrated significantly higher accuracy, correctly matching 100% (right) and 97% (left) of virtual setups, compared to the Bolton analysis (23% for both sides).
• A positive correlation was found between JB predictions and observed cusp-embrasure discrepancies.
• While the JB analysis correctly characterized discrepancies, it tended to overestimate their magnitude.

Conclusions:

• The JB analysis is a more accurate predictor of posterior ITSDs than the Bolton analysis when using virtual occlusal setups.
• Neither the Bolton nor the JB analysis precisely identified all clinically significant posterior ITSDs, indicating limitations in both methods.
• Further refinement of analytical methods is needed for precise identification of clinically significant posterior tooth-size discrepancies in orthodontics.