Approximately how long after eruption does the root apex of a permanent tooth complete closure?

Correct answer: C. About 3 years

• A. One year is too short — root formation is still incomplete at this stage.
• B. Six months is far too short; at eruption only about two-thirds of the root is formed.
• C. Correct. Root development and apical closure are completed approximately 3 years after eruption. This window explains why trauma to newly erupted incisors in children so often leaves an open apex requiring apexogenesis or apexification.
• D. Eight years greatly overstates the timeline.

Note: Worth raising with the study group.