3 Molar Movements for More Effective Class II Correction with Clear Aligners

There are many techniques and appliances to correct Class II malocclusions. When designing a digital process and using clear aligner therapy to treat Class II sagittal issues, consider predictable yet effective treatment design methods. Especially with a fully custom appliance, we are responsible for the proper design. For example, staging, final tooth positions, and adding force features to be effective.

Let’s focus on the molar movements since they are an essential component of Class II molar correction. The severity of the molar discrepancy will dictate some additional correction methods but mild to severe issues can benefit from typical molar movements.

Molar distal rotation

Many half-step Class II malocclusions present with the mesiolingual cusp of the first molar in the central fossa of the mandibular first molar. In these cases, distal rotation of the molar helps achieve Class I. When there is a more significant malocclusion, such as full-step Class II’s, we can combine this rotation with other movements. When we de-rotate molars, we can move the mesiobuccal cusp distally.  

Upper molar distal crown angulation

In fixed appliances, we can add tip-back bends and gain an improvement in molar position. Similarly, we can incorporate distal crown angulation with clear aligner treatment to tip-back the maxillary molars and achieve a Class I molar. This movement will facilitate a clockwise rotation of the molar and the occlusal plane. In combination with molar rotation and intermaxillary elastics, the level of Class II correction can increase significantly.

Lower molar mesial crown angulation

Lower arch movements can increase sagittal correction. We can adjust the angulation of mandibular molars to add further improvement combined with maxillary molar movement. Incorporating intermaxillary elastics and lower arch movements can add to the AP changes by moving the lower molars mesially and rotating the lower occlusal plane clockwise. These changes will add mandibular arch movements that will compliment maxillary correction of the Class II malocclusion.