Clinical Practice Pearls of the Pacific Getting the Right Rotation in Class II Maxillary Premolar Extraction Cases Dr. James Chen PCSO Bulletin Contributor San Francisco, CA 40 Maxillary premolar extraction is a common treatment option for moderate to severe Class II malocclusions present in nongrowing patients. The major compromise in maxillary premolar extraction cases is setting the maxillary molars into a full-cusp Class II position, with the mesial buccal cusp occluding between the mandibular first molars and second premolars. This requires more mesial-in rotation of the maxillary first molar. Adding mesial-in rotation in standard prescription buccal tubes will require bending the mesial in/ distal out detail bend, which will require converting the buccal tube or using a transpalatal arch. Given that both Roth and MBT prescriptions have mesial-out rotations (14° Roth and 10° MBT), you can take advantage of these prescriptions to add mesi- al-in rotation without additional bending. Exchanging the left and right tubes with each other will change the rotation from mesial-out to mesial-in; by switching the buccal tubes, the provider can use a straight wire to achieve the desired rotation. Exchanging the maxillary first molar buccal tubes with each other is not without side effects. One must monitor the buccolingual position of the maxillary second premolar. There is a chance that although the first molar is rotating in, the second premolar can be displaced buccally. In addition, switching bands will require changing the direction of the hook if elastics or elastomeric chains are needed. The hook can be bent to face the correct orientation, but care must be taken to not break it. PCSO Bulletin Spring 2020