Skin is able to repair itself and bones can readily fix themselves; in fact, most body parts are able to repair themselves over some period of time, but teeth don’t. Many ask why.
No Cells, No Healing
“Cells are what start the healing process in our bodies, and as tooth enamel consists of 90 percent minerals, there aren’t many proteins and cells there,” explains Janne Reseland, a professor of biomaterials at the University of Oslo (UiO).
She explains that at the base of the roots of our teeth we have cells that can provide a certain amount of repair, but not up in the crowns.
This leaves a large section of teeth’s surface area highly sensitive to the environment – what we breathe and what we eat and drink.
Anatomy of a Tooth
A tooth may seem like a single entity, but as with any other part of the body, it’s not as simple as it may seem on the surface. A tooth actually comprises a number of components.
There are three layers to the crown of a single tooth, namely enamel, dentin, and pulp.
Nature only provides us with two sets of teeth. First, our baby teeth, which are then exchanged for a set that is supposed to last a lifetime.
Enamel (the outer layer):
Formed by ameloblasts, which are lost when your teeth erupt, and they don’t come back. As a result, enamel does not have self-reparative properties.
formed by ameloblasts, which are lost when your teeth erupt, and they don’t come back. As a result, enamel does not have self-reparative properties.
Dentin (the middle layer):
Maintained by odontoblasts, which are present inside the pulp and get into the dentin through long processes extending from the cell. The odontoblasts can lay down secondary dentin (which is secreted slowly over the lifetime of the individual) and tertiary dentin (in response to an irritant, such as decay). This doesn’t mean that it can grow new dentin; it merely mineralizes the processes’ tubule. That is, a large fracture isn’t going to grow a new area of dentin, but the holes in it could be filled. It’s like if you burst a tire, you can patch it with glue, but you can’t build a new tire from the glue.
Pulp (the inner layer):
The area with nervous and vascular tissue, and contains the odontoblasts as well as progenitor cells that can turn into odontoblasts if needed (if the original odontoblasts were killed off by bacteria, for example).
In short, the difference is that teeth don’t have the same cells that bone does, and as a result, they have a very limited ability to repair themselves.