Predictability of Yen Angle, W Angle and Tau Angle and Their Correlation with ANB Angle, Beta Angle and Wit’s Appraisal for Assessment of True Sagittal Skeletal Maxillomandibular Relationship - A Cephalometric Study

Abstract

Aim: To access predictability of Yen angle, W angle and Tau angle by correlating them with ANB angle, Beta angle and WIT’s appraisal as True Sagittal Skeletal Maxillomandibular relationship indicators.

Study Design: A cross-sectional cephalometric study was carried out by including total 90 lateral cephalograms based on the inclusion and exclusion criteria. These 90 cephalograms were equally divided into Skeletal Class I, II and III groups based on the ANB angle, Beta angle and Wit’s appraisal. Further, the correlation of newer angles i.e. Tau angle, Yen angle and W angle with gold standard indicators i.e. ANB angle, Beta angle and Wit’s appraisal was carried out to determine the best possible indicator for assessing True Sagittal Skeletal Maxillomandibular relationship.

Results: The newer angles i.e. Tau angle, Yen angle and W angle provided varying result for Class I, II and III sagittal relationships when compared to combined indicators (ANB angle, Beta angle and Wit’s appraisal). Yen angle provided 10% predictability for Class I, 12.2% for Class II and 25.6% for Class III. Tau angle exhibited 13.3% predictability for Class I, 14.4% for Class II and 20.0% for Class III. Whereas, W angle showed 13.3% predictability for Class I, 8.9% for Class II and 21.1% for Class III. Furthermore, the kappa statistics of Tau angle and Yen angle was similar i.e. 0.217 similar. On contrary, the kappa statistics for W angle was 0.150.

Conclusion: True Sagittal Skeletal Maxillomandibular relationship was more accurately predicted by Tau angle and Yen angle amongst all newer angles.