Question

In the system used by the armed services for numbering teeth, which tooth corresponds to number 13?

A) Upper right first molar
B) Lower right first molar
C) Upper left first molar
D) Lower left first molar

Answer 1

Tooth number 13 in the system used by the armed services corresponds to the upper left first molar. The numbering starts with the upper right third molar as number 1, moves to the upper left, and then to the lower left, ending at the lower right third molar as number 32.

Step-by-step explanation:

In the numbering system used by the armed services, which is also known as the Universal Numbering System, tooth number 13 corresponds to the upper left first molar. This system starts with the upper right third molar (wisdom tooth) as tooth number 1, and the numbers continue along the upper teeth to the left side. They then drop down to the lower left third molar as tooth number 17 and continue to the right side, ending with the lower right third molar, tooth number 32.

Since the upper left quadrant of the mouth is denoted by numbers 9 through 16, the first molar on the upper left side, which is typically the sixth tooth from the front when standing outside the mouth and facing it, would be numbered as 13. Therefore, the correct answer to the question is C) Upper left first molar.