Metal Mouth Message Board

I had my second adjustment today to have my archwire changed out. I asked the tech how large the new archwire was and he said 18. I asked how large the one he took out was and he said "the thinnest". Not sure what "the thinnest" means. Does anyone know the diameter of the thinnest archwire? Also, how large to they get? Where does 18 fit on the scale of archwires?

Ah! Was able to find the answer to my own question. Here it is in case anyone else ever wonders:

Generally the orthodontic archwires are made from a stainless steel wire (spring wire) having a diameter of 0.01 to 0.022 inches for the round wires and cross-section of 0.10 × 0.020 to 0.022 × 0.028 inches for the rectangular wires.

I went from a 0.01 round wire to a 0.018 x 0.018 rectangular wire. Wow. Seems like a big jump.

WOW! This all sounds so complicated... All I know is that my wires are now more visible than they were in the beginning, as they are thicker and stronger. I don't know what shape they are either, but think they might rectangles right now.

Most orthodontists don't use a wire as thin as 0.010 inches, I would say the most common "thinnest" wire is 0.014" in diameter. If the tech told you the new one is an "18", I would guess that it is round, rather than rectangular. But, myabe not. The move from a 0.014 nickel titanium to a 0.018 is not that big, and is very common.

My first wire was a 0.012" round wire and I kept it for 2 adjustments. My ortho said I needed a very flexible wire because my top teeth were so misaligned.

I've gradually worked my way "up" and I now have 18x25 SS square wire on the bottom and a slightly thinner square one on the top (not sure what it is)