Gjessing canine is made up of
0.18 x 0.25 stainless steel rectangular wire
0.16 x 0.22 stainless steel rectangular wire
0.17 x 0.25 TMA wire
0.15 x 0.22 TMA wire
The PG spring is made in 0.016″x.022″ stainless steel rectangular wire. It has gingivally directed overlapping double helices, ovoid in shape, 10 mm in height and 5.5 mm at its widest part. It also has a small occlusal helix 2 mm in diameter.
The spring induces bodily movement of teeth and anchorage, reinforcement by a Nance button or headgear is needed in moderate to high anchorage cases. A prerequisite before placing this spring is good rotational correction as well as leveling and alignment of the three teeth involved.
PG canine retraction spring was introduced to the orthodontic profession way back in 1985 by Poul Gjessing, hence also known as Gjessing Canine.