Why do teeth get cracks?
Cracked tooth syndrome is a very common problem, usually affecting teeth that are heavily filled. The decay and subsequent filling causes a weakening of the remaining tooth structure. Like all materials, teeth are subject to stress and fatigue. After many bites on the tooth(stress cycles), a hairline fracture can develop, usually at the bottom corner of the cavity. If you are under a lot of physical stress, you may grind your teeth (usually at night)
Why does it hurt to bite on?
As the tooth flexes microscopically, the nerve is stimulated via tiny tubes (tubules) which are situated in the dentine (the inner core of the tooth, below the enamel). The tubules run down to the nerve and the fluid moves in them – which you feel as a sharp pain.
Why does it sometimes hurt to hot and cold?
The nerve is aggravated by the crack and by the bacteria being pumped into it via the tubules. It becomes inflamed because of the toxins in the bacteria. A classic symptom of nerve inflammation is hot and cold sensitivity.
If I do nothing what eventually happens?
The crack continues to slowly propagate (spread) like a crack in glass. Sometimes the crack goes off to the side and the fragment of tooth breaks off. The crack can also go deep into the root and at times right into the nerve. Teeth can often go for months in a stable, yet inflamed condition. Sometimes they seem to get better, only to suddenly get worse. It is hard to predict course of the unearthed tooth, but usually it is a slow, downhill slide as the crack deepens. It is not a good idea to leave it, because a small crack can be treated effectively, but a bigger one can lead to root canal treatment or extraction if you are unlucky. The nerve can be attacked by the bacteria, leading to extreme sensitivity to hot and/or cold and a persistent ache in the tooth as it dies, usually of modern to severe intensity. The infection in the nerve can then spread into the bone underneath, causing an abscess. This pain is usually severe, not effectively controlled by pain killers.