目的: 观察牙根发育情况，评价iRoot BP Plus与氢氧化钙用于年轻恒牙外伤露髓后部分牙髓切断治疗3年的临床随机对照实验效果。方法: 选取符合入组条件的外伤冠折露髓的年轻恒牙104颗，随机分为2组, 每组52颗，分别应用iRoot BP Plus(iRoot)和氢氧化钙(calcium hydroxide，CH)作为盖髓剂进行部分牙髓切断术治疗。术后1、3、6、12、18、24、30、36个月复查，通过临床及影像学检查观察牙根发育情况，评价临床疗效。结果: CH组和iRoot组最终分别有44颗牙(失访8颗，失访率15.4%)和45颗牙(7颗失访，失访率13.5%)纳入本研究，采用符合方案分析方法的成功率分别为80%和87%，采用意向治疗方案分析方法的成功率分别为67%和75%，两组间差异均无统计学意义(非劣效界值为-10%，疗效差异的95%CI为-8%~22%)。牙髓切断治疗牙的牙根继续发育，根管壁厚度与健康同名对照牙相比差异无统计学意义。iRoot组近冠1/3根管壁厚度比CH组略薄[(1.82±0.21) mm vs. (1.91±0.20) mm，P=0.047]。结论: iRoot BP Plus用于年轻恒牙外伤露髓后牙髓切断治疗可以有效保存活髓，且促进了牙根的继续发育。

Objective: To investigate the clinical and radiographic outcomes of 3 years after partial pulpotomy with iRoot BP Plus in immature permanent teeth with complex crown fracture and to provide refe-rence for the clinical application. Methods: The study was prospectively designed and 104 immature permanent teeth with complex crown fracture were randomly allocated into two groups (n=52). The experiment group received iRoot BP Plus as the pulp capping agent while the control group received calcium hydroxide as the pulp capping agent. After partial pulpotomy, all teeth were clinically and radiographically assessed at the end of 1, 3, 6, 12, 18, 24, 30, and 36 months. The success rate in the two groups was evaluated to see if there was significant difference. The root canal wall thickness in the treated teeth was compared both between the groups and within the groups with those of the corresponding healthy teeth on the opposite side, in the same patient. Results: Excluding those lost to follow-up, there were 44 teeth in calcium hydroxide group (8 teeth accounting for 15.4% were lost to follow up) and 45 teeth in iRoot BP Plus group (7 teeth accounting for 13.5% were lost to follow up) in the end. There was no intergroup difference in the success rate between calcium hydroxide group and iRoot BP Plus group (per-protocol analysis: 80% vs. 87%; intent-to-treat analysis: 67% vs. 75%). The non-inferiority margin was -10%. The 95% confidence interval of the difference in success rate was -8% to 22%. There was no significant difference in root development between the experimental teeth and contralateral control teeth. The thickness of upper 1/3 root canal in the iRoot BP Plus group was thinner than that in the CH group [(1.82±0.21) mm vs. (1.91±0.20) mm, P=0.047]. Conclusion: iRoot BP Plus used in pulpotomy can effectively preserve the living pulp and promote the development of root in the young permanent teeth with complex crown fracture.