tissue), these hairs would run up inside each straw.

Covering the outer ends of the straw tubes is the enamel which is a very hard crystalline material. This outer surface is the surface that takes all the abuse of the food we eat, fluids we drink, and trauma when we bite and chew, or get hit in the mouth during sports, brawls and accidents. The reason that our teeth do not fracture all fall apart after each knock is their unique design. The dentine is 50% water, and the tubular construction when wet with nerve fluids keeps this material flexible, and able to absorb energy. So, you may well have many fracture lines that you can see in your own teeth, but the properties of the dentine bind the whole tooth together and keep it intact and functional. The analogy that I use to my Patients is a grass leaf. When wet, it can be folded, knotted and woven. These processes can be reversed, and the leaf returned to a single leaf, usually without breakage. But once the grass leaf dries to become hay, it is fragile and brittle. If you attempted to fold, knot or weave it is this dried state, it would probably break or fracture. Nature has many other examples of this.

Now once the acids and bacterial by-products gain entry into the dentine, the rate of penetration and destruction is increased by its unique 'straw-like' construction. Depending on where the decay area started in the tooth, and the shape of the advancing decay, structural failure of portions of the tooth, or the whole crown, can occur. Unless this stage is quickly stabilised, the nerve tissue will die, leading ultimately to infection within the supporting bone tissue.