Clinical application of a method to correct angle ANB for geometric effects
1Department of Orthodontics, University of Oklahoma, College of Dentistry, Oklahoma City.
Summary
The Wits appraisal offers a more accurate assessment of jaw skeletal discrepancy than the ANB angle by correcting for four geometric factors. This method improves the diagnosis of Class II and Class III skeletal relationships.
Area of Science:
- Orthodontics
- Cephalometric analysis
Background:
- The ANB angle is commonly used to assess sagittal skeletal discrepancies but is influenced by geometric factors.
- Previous attempts to refine assessment include quadrilateral and Wits analyses.
Purpose of the Study:
- To evaluate and eliminate four geometric factors affecting the ANB angle.
- To introduce a corrected method for assessing skeletal discrepancies in the sagittal plane.
Main Methods:
- Utilized the Wits appraisal, setting a Wits appraisal of zero as a Class I skeletal relationship.
- Derived a mathematical formula to quantify the influence of anteroposterior position of point N, occlusal plane inclination, dental height, and N-B distance on the ANB angle.
- Applied the method to 508 patients.
Main Results:
- The Wits appraisal, by accounting for four geometric factors, provides a more accurate assessment of skeletal relationships compared to the uncorrected ANB angle.
- Geometric influences can obscure the true skeletal relationship when only the ANB angle is considered.
Conclusions:
- The Wits appraisal offers a superior method for evaluating sagittal jaw discrepancies.
- Correcting for geometric factors is crucial for accurate diagnosis of skeletal Class I, II, and III relationships.
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