Front to back - First insert the aligner on the front teeth; then push the tray down over the back teeth. This technique is useful when the anterior teeth are excessively slanted forward or excessively crowded.
Back to front - Insert the aligner on the back teeth first; then push the tray down over the front teeth. This technique is useful when all of the teeth are relatively straight.
Side to side - Side to side technique can be used when the back teeth are excessively slanted towards the tongue. Insert one side of the aligner first, then come forward to insert the front teeth. Lastly press down on the other side. front then toward the tongue or toward the cheek - Use this technique when the teeth are widened either lingually (toward the tongue) or buccally (toward the cheek). First insert the aligner on the front teeth. Then push the tray down lingually, if the teeth are widened lingually or buccally, if the teeth are widened buccally.