American Board of Orthodontics (ABO) Practice Exam

What adjustment of the occlusal plane allows for maximum chin projection?

1. Gradual lateral expansion

2. Flattening of the occlusal plane

3. Elevation of the posterior segment

4. Inclination towards the anterior region

The correct answer is: Flattening of the occlusal plane

Flattening of the occlusal plane facilitates maximum chin projection by optimizing the alignment and positioning of the dental and skeletal structures within the face. This adjustment allows for a more horizontal orientation of the occlusal surface, which can enhance the relationship between the maxilla and mandible, ultimately affecting the position of the chin. When the occlusal plane is flattened, it creates a more favorable angle between the occlusal surfaces and the underlying jaw structure. This can lead to an increased perception of chin prominence, as the orientation aligns well with the facial aesthetic and natural morphology, projecting the chin forward relative to the rest of the facial structures. This is often sought in orthodontic treatments to improve facial profile and balance. Other adjustments like lateral expansion, elevation of the posterior segment, or inclination towards the anterior region do not provide the same direct benefit for enhancing chin projection. Each of these adjustments may alternatively affect occlusal relationships, dental arch forms, or facial aesthetics, but none align with the goal of maximizing chin projection as effectively as flattening the occlusal plane.