Adult dental braces seem to be on the rise, with advances in technology creating increasingly discrete products. Whether it be to improve someone’s bite, or for a beautiful smile, I think it is fascinating that we can control and move our teeth. The brace works by applying force and triggering a biomechanical process called “bone remodelling”. I didn’t know much about this, so thought it was worth a quick investigation.
Throughout our entire life our bones are constantly forming new bone tissue, in our first year we replace almost all our bones in our skeleton! The body removes mature bony tissue, replacing it with new bone in a process called ossification, or more simply “bone formation”. This happens not only as we grow, but also in fractures or for everyday bone running repairs, and it’s this which means our teeth can be moved.
The enamel on the outside of each tooth provides the strength essential to bite into hard food, but it’s the root of each tooth, anchored in the jaw bone, which keeps our teeth in place. When a brace is worn, the applied pressure triggers bone cells, called osteoclasts, to break down the bone around the root. This creates a space for the root to move into. As the tooth and the tooth root are connected, the change in location of the root also makes the visible tooth move. Cleverly, to secure the tooth in the new spot, the body uses another set of bone cells, osteoblasts, growing new bone to lock the root into place. Although a tooth cannot move quickly, typically a millimetre a month, through constant gentle pressure amazing results can be achieved.
I hadn’t realised the range of dental appliances that are available today. A fixed brace comprises of a bracket (the bit stuck onto each tooth) and an alloy based arch wire (the linking wire between the teeth). The wire can be held into the bracket by elastic bands; this is when you see the great colour combinations! Alternatively, some bracket systems use a click and lock method, so removing the need for the bands altogether. In a neat twist you can now have the brackets attached to the outside of your teeth or hidden on the inside; with the inside ones unless you tilt you head no-one will ever see them! As well as fixed braces, clear trays can be used which lock over the teeth (you get to take these ones out to eat). By moving through a series of slightly different tray shapes, the teeth can be guided into their new alignment.
All of these braces are essentially applying the same approach; a gentle force to move the tooth root and none of them would work without the amazing ability of our body to undergo bone remodelling!