The reasons for teeth not being able to bite are: first, long-term wear causes damage to the morphology of the jaw and neck of the teeth, the upper and lower teeth cannot achieve precise occlusion, chewing efficiency decreases, and cannot cut and tear food; second, when there are hidden cracks or deep cavities in the crown, the stimulation of chewing and eating will be transmitted to the pulp causing pain; third, when chronic periapical inflammation occurs, the inflammatory secretions produced by the root tip make the teeth feel floating, causing When there are multiple missing teeth, the upper and lower teeth cannot form a complete occlusal contact and lose the chewing function and cannot eat, and need to repair the missing teeth in time to chew normally.