Objective:To treatment the young permanent incisors with exposed pulps in crown by pulpotomy and observe the growth of root canals and apexogenesis following up over 2 years.

目的：对外伤引起的年轻恒前牙冠折露髓行活髓切断术，并于2年以上追踪观察其根管、根尖孔发育情况。