Teeth have cracks, if the cracks are deep, the lesions may continue to develop, affecting the use of teeth, if the cracks are shallow, in the absence of other diseases can generally be used permanently, as follows. 1. Deep cracks: the affected teeth may have excitation pain, occlusal pain, spontaneous pain, pulp may appear under long-term stimulation of pulpitis or even pulp necrosis, pulp necrosis of the tooth becomes brittle, may be broken or fractured within 1~2 years, affecting the normal use of the tooth. 2. Cracks are shallow: Usually it will not affect the use, if the tooth is accidentally pressed by hard objects, such as stones, bones, etc., the cracks may deepen, and the above symptoms will appear. If the cracks are serious, or there are other symptoms, it is recommended to go to the hospital in time.