ISO system for primary dentition

Upper right quadrant (maxillary) - 5

Upper left quadrant (maxillary) - 6

Lower left quadrant (mandibular) - 7

Lower right quadrant (mandibular) - 8


Medial/ central incisors - 1

Lateral incisors - 2

Canines - 3

1st molars - 4

2nd molars - 5


For example, the lateral incisor in the lower left quadrant has a numbering of 72 (7 is for the lower left quadrant, while 2 refers to the lateral incisor as it is the second tooth from the midline of the jaw).