The wire size is 0.5mm in this case. 0.6mm can be used if the spring gets bigger/longer, where it can be used to move two teeth simultaneously. As long as the arm contacting the tooth being moved is not wider than it, then the 'second' coil and arm can be wider as they don't actually move forward, only rotate. Hope that helps everyone and thanks for all your comments.
Thanks for your answer, and I don't wish to be too critical as I appreciate what you're trying to do, but I think it only fair to give those watching this a proper understanding. Looking at your spring, the mesial coil lines up with the mesial of the lateral, but the distal coil extends past the distal line of the lateral. You are partly right in what you state, the distal coil does not move, only rotate.However, by the very nature of the rotational movement of the distal coil the second (mesial) coil must move forward (labially) and if it was to extend past the point of the mesial edge it could contact the abutment tooth. As this is an educational video from a respected seat of learning I feel that basic foundations should be put across, otherwise someone watching this may believe there's no limit to the width. Sorry for the long reply.
+Chris Dodd There is an increase in flexibility with having the helices further apart; allows for a greater range of motion as well. The activation can be easier with more space around them as well (acrylic spacing comes into play here too)
I thought a 'Z' spring was supposed to fit within the width of the tooth it was moving, otherwise it interferes with the abutment teeth. It would be helpful if you'd stated what size wire you were using. 0.5mm or 0.4mm?
