The following aspects can be used to distinguish between milk teeth and permanent teeth: 1. Milk teeth are white in color and have short crowns, while permanent teeth are yellowish in color and have wide crowns. 2. Milk teeth have prominent necks, distinct crowns and roots, and significantly narrower roots, especially the milk anterior teeth show the characteristics of wide crowns and narrow roots. The crowns of the permanent teeth are higher, and the demarcation between the crowns and the roots is not clear.3. The proximal cusp ridge of the crowns of the milk cusp teeth is longer than the distal cusp ridge, and the cusps are biased toward the distal center, contrary to the permanent cusp teeth.4. The width of the milk teeth is significantly smaller than that of the permanent teeth, and during the replacement period of the milk and permanent teeth, the gap between the milk teeth increases and food is easily embedded, and the roots begin to loosen and eventually fall out.