Tooth movement in sagittal and transversal direction
The spring contacts the tooth being moved interdentally and therefore, is also called interdental spring, intermediate spring, mesial or distal spring.
The entire resilient portion of the spring is covered with wax in order to make activation possible. The whole active portion, as well as the retention, should maintain a distance of approximately 1 mm to the gingival tissue.
When the spring is covered properly with wax and the appliance is finished there is enough free play to activate the spring.
