1, central incisor (incisor)
Mandibular 6 months, maxillary 7.5 months. The crown width of mandibular central incisor is about 2/3 of the width of maxillary central incisor, which is the smallest tooth in the whole permanent teeth. Symmetrical, narrow and flat, straight, with a gourd-shaped section of 1/3 at the root.
2. Side incisors (teeth next to incisors)
Mandibular 8 months, maxillary 10 months. There are 4 central incisors and 4 lateral incisors adjacent to the central incisors. Central incisors and lateral incisors form a group of incisors, which have the function of cutting food into pieces.
3. The first deciduous molar (the big tooth near the front teeth)
Mandibular 12 months, maxillary 14 months. The first permanent molar is the first tooth in the permanent dentition. The tooth germ of the first permanent molar begins to form at about 3-4 months of embryo, and begins to calcify at birth, and the calcification of the crown is completed at about 2-3 years old.
4, canine teeth (tiger teeth)
Mandibular 16 months, maxillary 18 months. In mammals and mammals-like animals, the long, pointed teeth between the incisors and premolars.
5. The second deciduous molar (the largest tooth farthest from the front tooth)
Mandibular 20 months, maxillary 2 years old. The mandibular second molar is similar to the mandibular first molar in shape, and can be divided into four-pointed type and five-pointed type according to the occlusal surface shape. Four-pointed type is the main type of mandibular second molar, and the occlusal surface is square with four sharp points, of which the mesiobuccal side and the tip of the tongue are larger than the distal buccal side and the tip of the tongue.