Stoner Box Loop
One of my favourite tricks when it comes to aligning an ectopic canine is to make a stoner box loop. A .016 SS orthodontic archwire is bent to the chair in less than 2 minutes. It is important that all the segments of the arch are on the same plane once the loop is complete (photo B of case #1). This loop is then engaged and undergoes a deformation (photo E, case #1) which creates a system of force on the ectopic canine while minimising the secondary effects on the adjacent teeth. With the help of my colleagues Jean-Marc Retrouvey and Vishnu Raj, I designed the force system. The 1st system is the most complete and represents a combination of Burstone’s II and V geometries. The 2nd force system is simplified by dividing the box loop into 2 rectangular loops. Case #1 shows progress at 6 and 14 weeks. The purpose of these force systems is to illustrate the system that allows the canine to be straightened and extruded. Case 2 shows a box loop on a lower canine, so the axis was corrected in 11 weeks. Some may wonder why I used a continuous arch to align the upper canine in case #2. The difference with case #1 is that the axes of the cases are parallel. The force system then becomes a Class I geometry. Admittedly, side effects can occur on adjacent teeth, but extrusion is an easier and quicker movement than intrusion.