Cracked Tooth Syndrome
Ever bite hard and experience sharp pain on a tooth? This could be due to a crack through the tooth into the nerve chamber. As you chew, the tooth will flex about the crack and rip on the nerve inside. If pain goes away quick (within seconds of release), the treatment is a crown. If the condition goes untreated, cracks can widens and the pain becomes more constant requiring root canal and crown. If the crack extends deep, the tooth can't be saved.
It's beneficial to catch this quick as soon as it happens to avoid costly treatment or loosing a good tooth.