Malalignment of the second molars occurred in 16.98% (9/53) cases, such as buccally or lingually eruption resulting in buccal crossbite or lingual crossbite, rotations, mesial and distal impaction.

• 第二磨牙完全萌出及大部分萌出（已有（牙合）接触）的53例中，16.；98%25(9/53)的患者在萌出过程中曾出现错位，包括第二磨牙颊舌向错位、扭转、近远中阻生等。