We can correct Class II and Class III malocclusions with clear aligners. However, the predictability of the approach and the technique for sagittal correction has nuances. For the best outcomes, an orthodontist should consider the diagnosis of the AP issues and develop an effective treatment plan. Therefore, my recommendation on appliance design is to ensure we have the proper final tooth positions designed into the CAD software, efficient staging, and effective force systems.
Let’s focus on final tooth positions. They should be relevant to Class II or Class III sagittal correction. Thus, the primary focus will be tooth angulation, occlusal plane change, and vertical control.
Tooth Angulation
Posterior movements and canine position are important factors integrating into a sagittal correction. While aiming for Class I molar and canine position, we should consider the appropriate dental compensation. We can tip these teeth appropriately with the digital plan. For Class II correction, maxillary teeth should have a distal crown angulation component. Whereas mandibular teeth have mesial crown angulation. For Class III correction, maxillary teeth have mesial crown angulation movement. While mandibular teeth have a distal crown angulation in the treatment design.
Occlusal Plane Change
Sagittal corrections and the use of elastics will lead to occlusal plane changes. We can control occlusal plane changes with aligners, but I recommend designing the change to address the AP and vertical issues with the malocclusion. In Class II malocclusions, the occlusal plane should rotate clockwise. Class III malocclusions will need counterclockwise rotation on the occlusal plane.
Vertical Control
Patients who present with sagittal issues correspondingly have vertical problems. Vertical movements are necessary to achieve occlusal plane changes successfully. Depending on a deep bite or open bite correction, we have to add vertical tooth positions and the force features that help us achieve them.
