Teeth become crispy and brittle may be due to dental caries, dental dysplasia and other reasons. 1. Dental caries: It is related to poor oral hygiene, bad dietary habits, insufficient salivary secretion and other factors that can lead to cavities. If cavities are severe, the tooth substance can be damaged and the teeth can become thin. If too hard food is consumed, it may lead to partial chipping and loss of the carious part of the tooth. 2. Dental development problems: When the teeth are not well developed, the hardness of the teeth will deteriorate. They may become brittle when eating too hard food. In the case of teeth becoming crispy and fragile, you should go to the hospital in time, improve the examination to clarify the cause of the disease and carry out treatment under the guidance of the doctor.