Accuracy and reliability of tooth widths and Bolton ratios measured by ClinCheck Pro

Introduction: This study aimed to assess the accuracy and reliability of tooth widths and Bolton ratios measured in ClinCheck Pro.

Methods: Five sets of typodonts were scanned using an iTero scanner, and the digital models were electronically transmitted to Align Technology for treatment planning. The typodont teeth were then segmented and measured using 3-dimensional optical profilometry (3D OP) and a calibrated digital caliper. Tooth widths estimated by ClinCheck Pro were compared with those measurements obtained using 3D OP and digital calipers. To determine the reliability of ClinCheck Pro measured tooth widths and Bolton ratios, the records of 30 consecutive patients treated with the Invisalign appliance without interproximal reduction were obtained. Values at the initial ClinCheck Pro treatment plan were compared with those from additional aligner scans. Accuracy, the agreement between methods, and reliability were investigated using the Bland Altman method.

Results: A systematic under measurement was observed in the tooth widths measured by ClinCheck Pro (mean, 0.36 mm) compared with those obtained using 3D OP and digital caliper (individually segmented teeth). Although the overall reliability of ClinCheck Pro measured tooth widths was good (intraclass correlation coefficient, 0.96), the reliability of Bolton ratios was only moderate with wide confidence intervals.

Conclusions: ClinCheck Pro systematically underestimates tooth widths compared with 3D OP and digital caliper (individually segmented teeth). In addition, clinicians need to be cautious while relying solely on ClinCheck's Bolton ratios estimation for the treatment plan. These findings may be due to "shape assumptions" in the interproximal areas and could have clinical implications.