A chipped tooth can be caused by stress cracking or just a sharp blow to the tooth. As long as it's minor like in this picture it can be fixed with composite. If it goes into the nerve chamber of the tooth it will require a root canal and crown.
Chipped teeth have symptoms of increased temporary sensitivity to air, hot cold fluids, or any that's chewed into the area. It will be a sharp pain that quickly (within a second goes away).
The reason for this is dentinal sensitivity. When the outer enamel layer is chipped off into the dentinal layer it exposes the open tubules of dentin that communicate with the nerve directly.
Its important to get a chipped tooth repaired quickly because a slightly aggravated nerve in a healthy state can become irreversibly aggravated over time requiring root canal crown due to bacterial contamination of the tubules.
