The appearance of another tooth growing on top of the tooth, most of them have the following kinds of situations: First, because the child is in the period of tooth replacement, it may be that the pulp chamber bottom has been destroyed due to the decay of the milk tooth, so the new tooth may appear in the center of the old tooth when it erupts, making the milk tooth split and appearing overlapping growing teeth, it is suggested that the patient should immediately extract the unlossed milk tooth to prevent the eruption of permanent teeth and affect the correct position of permanent teeth; Second, due to the development of the tooth malformation, the emergence of malformed central cusp, so the teeth in the eruption of the above will appear extra cusp, feel like the middle of the teeth and grow teeth, this belongs to the normal phenomenon, parents do not have to worry too much, this is normal teeth, prevent too much wear in the middle of the cusp can be.