It is usually not normal for teeth to not be replaced at 14 years of age. Normally, the time for tooth replacement is from 6 to 13 years old, so it is not normal for a patient to not finish replacing his teeth at the age of 14. He should go to the hospital stomatology department for a radiograph to see if there are any problems such as impaired tooth eruption. However, it is also possible that genetic factors lead to slower physical development, which is a normal phenomenon and generally does not require special treatment. Tooth replacement is the process of shedding milk teeth and growing permanent teeth. Under normal circumstances, there is a corresponding permanent tooth embryo underneath the root of each milk tooth, and as the child grows and develops, the permanent tooth embryo will gradually develop and erupt one after another, and the permanent teeth will directly compress the milk tooth roots in the process of eruption, so that the roots of the milk teeth will gradually become shorter and shorter and absorb more and more, until they disappear completely. During tooth replacement, children may encounter problems such as retained milk teeth, early loss of milk teeth, difficulty in the eruption of permanent teeth, misaligned bites and double-layered teeth, and if there is a calcium deficiency in the body, it may also lead to slow development of the teeth. It is recommended that if your teeth have not been replaced by the age of 14, you should go to the hospital to find out the cause of the problem and have it treated under your doctor’s supervision.