Abnormal eruption patterns (such as a retained primary) can often cause one or two anteriors to erupt into cross-bite. Choosing the best appliance to correct this problem is dependent upon the depth of the bite, the space available, and whether or not an occlusal interference is involved. With this appliance, there is plenty of arch space to move the central forward. There are no occlusal interferences causing a mandibular shift...and the depth of the patient’s bite is ideal. A simple Hawley with a posterior occlusal bite plane and a recurved spring is used. The occlusal bite plane clears the occlusion sufficiently to let the recurved spring move the anterior forward, while preventing any unwanted change in the patient’s ideal vertical dimension. It also aids in appliance retention. Once the crossbite is corrected, the bite plane can be removed and the appliance can serve as a retainer. Note: If the spring is riding up the lingual incline of the central instead of pushing it forward, we recommend that you clear the acrylic away from the spring and add a small composite ledge on the lingual surface of the tooth to act as a positive sprint-stop. Removing the acrylic will also make it easier to adjust the spring with 139 bird-beak pliers.