What is it?

A series of ligatures connected to each other and used to pull teeth together with more strength is called a power chain, The ligature wires are flexible and can be twisted to tighten and secure the archwire in place during the later stages of treatment.

What is it used for?

Ligatures can also be made of wire. Self-ligation makes use of a bracket with a sliding or rotating mechanism to ligate an archwire. These may be used to hold or ligate the archwire in brackets or to tie segments of teeth together by wrapping around the brackets attached on teeth, resulting in straight teeth.