According to Baidu health data, the third molar: if the wisdom teeth of the extracted posterior molar are the third molar, there is almost no chewing function, and the patient can not install dentures at this time; Second molar: If the penultimate tooth is pulled out, it is the second molar. If the patient has no wisdom teeth or maxillary teeth, especially the elderly patients who lack the second molar or both the upper and lower jaws, they can generally not install dentures. Although the chewing ability and efficiency are reduced, the chewing function of the elderly can be basically guaranteed. For young people, it is generally recommended to install dentures in time to avoid tooth inclination, looseness or oral occlusion disorder; First molar: If the patient is missing the penultimate tooth, that is, the first molar, it usually needs to be repaired in time. If it is not repaired in time after tooth extraction, the left and right teeth and occlusal teeth may be squeezed into the gap where the teeth are missing, and the left and right teeth will become crooked, which will lead to the loosening of the whole dentition, the widening of the teeth gap and the lengthening of the occlusal teeth, which will affect the chewing function. Long-term occlusion requires the installation of dentures.