In microdentition, the sum of mesiodistal diameters of the four upper incisors is most likely to be less than which value?

In microdentition, the sum of mesiodistal diameters of the four upper incisors is most likely to be less than which value?

• A. Less than 28 mm
• B. Less than 30 mm
• C. Over 32 mm
• D. Less than 36 mm

Answer: (A)

In microdentition, the teeth are small, so the combined mesiodistal width of the four upper incisors tends to be in the mid-twenties of millimeters. Centrals are roughly 6.5–7.0 mm each and laterals about 5.5–6.0 mm each. Adding two of each gives about 23–26 mm in total. Because of this, the sum is very commonly under 28 mm, making that threshold the most consistent upper bound. It would also be under 30 or 36 mm, but 28 mm is the tightest value that’s rarely exceeded in primary dentition.

In microdentition, the teeth are small, so the combined mesiodistal width of the four upper incisors tends to be in the mid-twenties of millimeters. Centrals are roughly 6.5–7.0 mm each and laterals about 5.5–6.0 mm each. Adding two of each gives about 23–26 mm in total. Because of this, the sum is very commonly under 28 mm, making that threshold the most consistent upper bound. It would also be under 30 or 36 mm, but 28 mm is the tightest value that’s rarely exceeded in primary dentition.