Braces and How They Work and What They are Made Of

Four basic components make up braces:

1. Brackets: made from metal or ceramic. A bracket is attached to each tooth
2. Bands: are metal rings that are usually placed only on the back teeth
3. Arch wire: which is a think metal wire that runs from bracket to bracket and puts pressure on the teeth
4. Elastic Ligature Tie (a.k.a o-ring): is a small coloured elastic that holds the bracket on the arch wire. The ligatures are usually changed at each adjustment visit.
1. the brackets and bands are held on to the teeth by bonding material (glue)
2. accessories on the braces such as headgear tubs, hooks, loops, and steel ties are also often used for maxium control and tooth movement

How all this is able to move the teeth:

The teeth move when the arch wire puts pressure on the brackets and teeth. Sometimes, springs or rubber bands are used to exert more force in a specific direction. Braces exert constant pressure, which over time, more teeth into their proper positions

Your teeth are surrounded on top by gum tissue (also called gingiva). Under the gum tissue, the periodontal membrane (sometimes called the periodontal ligament or PDL) encases the bottom portion of the tooth. Next to that lies the alveolar bone.

When braces put pressure on your teeth, the periodontal membrane stretches on one side and is compressed on the other. This loosens the tooth. The bone then grows in to support the tooth in its new position. Technically this is called bone remodelling.

Bone remodelling is a biomechanical process responsible for making bone stronger in response to sustained load-bearing activity and weaker in the absence of carrying a load. Bones are made of celled called osteoclast (bone destroying cells)  and osertoblasts (bone forming cells).

Bone remolding works like this: increase the load on a bone and osteoclasts are created which break it down in response to the load. Remove the load and osteoblasts are created which create new bony cells. Repeat the process through repetitive motions (tightening of the braces) and eventually the done density increases

Your teeth are socketed in bone. A mentioned, surrounding each tooth is a PDL which attached it to the surrounding bone,

The PDL as a sort of messenger between teeth and surrounding bony sockets. Pressure between the PDL and bone causes the bone to create osteoclasts and breakdown the bone to restore the normal spacing between the teeth and bone. The corresponding tension on the PDL behind the movement causes the bone to create osteoblasts, effectively building new bone to fill in the difference and restore the normal spacing between teeth and bone. Not a whole lot of force is necessary, only some force which is not normally present.

This is where the brackets and archwire come into the picture - they generate the artificial force needed to create and sustain the pressure.