IJOMAHIP Published Article Details

Abstract Accurate assessment of sagittal jaw relationships is fundamental to orthodontic diagnosis and treatment planning; however, no single cephalometric parameter can completely describe the complexity of skeletal jaw disproportion. Although the ANB angle remains the gold standard, its accuracy may be affected by growth, jaw rotation, and anatomical variations. This study investigated the relationship between the conventional ANB angle and the novel Tau angle in assessing sagittal jaw disproportion among Filipino patients with skeletal Class I, II, and III malocclusions. Methods. This descriptive-correlational study included 80 lateral cephalometric radiographs of Filipino male and female patients with skeletal Class I, II, and III malocclusions obtained from a dental clinic in Quezon City, Philippines. Each radiograph was analyzed using both the conventional ANB angle and the novel Tau angle. Interpretations were based on established Filipino and Asian normative values, and all landmark identification, tracing, and interpretations were validated independently by three certified orthodontists. Statistical analyses were performed to determine differences according to age and sex and to evaluate the relationship between the two cephalometric analyses using Kendall's Tau-b correlation. Results. No significant differences in sagittal jaw disproportion were observed across age groups or between males and females using either the ANB or Tau angle analyses, indicating that age and sex did not influence skeletal classification. A strong positive correlation was found between the ANB and Tau angle analyses (Kendall's Tau-b = 0.79, p < 0.01), demonstrating comparable reliability in classifying sagittal jaw relationships. Conclusion. The Tau angle showed comparable reliability to the conventional ANB angle in classifying sagittal jaw disproportion and may serve as a dependable alternative when ANB landmarks are obscured or difficult to identify. These findings support the incorporation of the Tau angle into routine orthodontic diagnosis, education, and artificial intelligence-assisted cephalometric analysis, while further studies are recommended to establish normative Tau angle values for the Filipino population. Keywords: ANB Angle, cephalometric analysis, orthodontic diagnosis, sagittal jaw disproportion, skeletal malocclusion, Tau angle, ANB angle