A decreased occlusal plane angle indicates what type of rotation?

A decreased occlusal plane angle indicates anticlockwise rotation, which is associated with an inclination of the occlusal plane upward in the posterior region relative to the anterior region. When the occlusal plane angle decreases, it suggests that the maxillary plane is positioned more vertically, which generally occurs when the mandible rotates in an anticlockwise direction. This type of rotation often leads to a more favorable occlusion by reducing the vertical dimension in the posterior part and increasing it in the anterior region, promoting better alignment of the teeth and improving the functional relationship between the upper and lower jaws.

In cephalometric analysis, recognizing this type of angular change is crucial for diagnosing malocclusion and planning orthodontic treatment effectively.