The star marks tooth number 31.

The star marks tooth number 31.

• A. 31
• B. 28
• C. 4
• D. 18

Answer: (A)

Understanding how the universal numbering system identifies teeth is being tested. In this system, teeth are numbered 1 through 32, starting at the upper right third molar, across to the upper left third molar, then continuing on the bottom from the lower left third molar to the lower right third molar. A star marking tooth number 31 tells you exactly which tooth is being referred to. In this scheme, 31 corresponds to the lower right second molar, so the option that shows 31 is the correct one. The other numbers would label different teeth, not the one marked by the star.

Understanding how the universal numbering system identifies teeth is being tested. In this system, teeth are numbered 1 through 32, starting at the upper right third molar, across to the upper left third molar, then continuing on the bottom from the lower left third molar to the lower right third molar. A star marking tooth number 31 tells you exactly which tooth is being referred to. In this scheme, 31 corresponds to the lower right second molar, so the option that shows 31 is the correct one. The other numbers would label different teeth, not the one marked by the star.