Objective: This study aimed to explore the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in patients with high-angle skeletal Class Ⅱ open bite, aiming to provide a reference for clinical treatment. . Methods: This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. CBCT images of eighty-one untreated patients (40 anterior open bite patients and 41 normal overbite patients) with high-angle skeletal Class Ⅱ malocclusion were selected before treatment. Dolphin software was used to study the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology, and the differences between the two groups were analyzed. Results: There was no statistical significance in the root length of maxillary lateral incisor and canine between the open bite group and the normal overbite group, significant differences were found in the root length of maxillary central incisor （11.12 ± 1.37） mm、mandibular central incisor（10.15 ± 1.09）mm, mandibular lateral incisor（11.27 ± 1.15）mm and mandibular canine（12.81 ± 1.48）mm between the open bite group and the normal overbite group（P<0.05）. On the other hand, the two groups were significantly different in crown-root morphology of the maxillary central incisor (1.10° ± 3.62° vs. 4.53° ± 2.30°, P<0.01) but not in the mandibular central incisor. Conclusion The root length of the maxillary central incisor, mandibular central incisor, mandibular lateral incisor, mandibular canine in high-angle Class Ⅱ open bite patients is shorter than that in high-angle Class Ⅱ normal overbite patients, and the long axis of the crown of the maxillary central incisor in high-angle Class Ⅱ open bite patients obviously deviates toward the labial side relative to the long axis of the root. The crown-root angle is smaller, which is beneficial to torque control or adduction movement of the anterior teeth in high-angle Class Ⅱ open bite patients.

Objective This study aimed to explore the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in patients with high-angle skeletal Class Ⅱ open bite,aiming to provide a refer-ence for clinical treatment.Methods This study was reviewed and approved by the Ethics Committee,and informed consent was obtained from the patients.CBCT images of eighty-one untreated patients(40 anterior open bite patients and 41 normal overbite patients)with high-angle skeletal Class Ⅱ malocclusion were selected before treatment.Dolphin software was used to study the root length of maxillary and mandibular anterior teeth and central incisor crown-root mor-phology,and the differences between the two groups were analyzed.Results There was no statistical significance in the root length of maxillary lateral incisor and canine between the open bite group and the normal overbite group,signifi-cant differences were found in the root length of maxillary central incisor(11.12±1.37)mm、mandibular central inci-sor(10.15±1.09)mm,mandibular lateral incisor(11.27±1.15)mm and mandibular canine(12.81±1.48)mm be-tween the open bite group and the normal overbite group(P＜0.05).On the other hand,the two groups were significant-ly different in crown-root morphology of the maxillary central incisor(1.10°±3.62° vs.4.53°±2.30°,P＜0.01)but not in the mandibular central incisor.Conclusion The root length of the maxillary central incisor,mandibular central inci-sor,mandibular lateral incisor,mandibular canine in high-angle Class Ⅱ open bite patients is shorter than that in high-angle Class Ⅱ normal overbite patients,and the long axis of the crown of the maxillary central incisor in high-angle Class Ⅱ open bite patients obviously deviates toward the labial side relative to the long axis of the root.The crown-root angle is smaller,which is beneficial to torque control or adduction movement of the anterior teeth in high-angle Class Ⅱopen bite patients.

Objective This study aimed to explore the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in patients with high-angle skeletal Class Ⅱ open bite,aiming to provide a refer-ence for clinical treatment.Methods This study was reviewed and approved by the Ethics Committee,and informed consent was obtained from the patients.CBCT images of eighty-one untreated patients(40 anterior open bite patients and 41 normal overbite patients)with high-angle skeletal Class Ⅱ malocclusion were selected before treatment.Dolphin software was used to study the root length of maxillary and mandibular anterior teeth and central incisor crown-root mor-phology,and the differences between the two groups were analyzed.Results There was no statistical significance in the root length of maxillary lateral incisor and canine between the open bite group and the normal overbite group,signifi-cant differences were found in the root length of maxillary central incisor(11.12±1.37)mm、mandibular central inci-sor(10.15±1.09)mm,mandibular lateral incisor(11.27±1.15)mm and mandibular canine(12.81±1.48)mm be-tween the open bite group and the normal overbite group(P＜0.05).On the other hand,the two groups were significant-ly different in crown-root morphology of the maxillary central incisor(1.10°±3.62° vs.4.53°±2.30°,P＜0.01)but not in the mandibular central incisor.Conclusion The root length of the maxillary central incisor,mandibular central inci-sor,mandibular lateral incisor,mandibular canine in high-angle Class Ⅱ open bite patients is shorter than that in high-angle Class Ⅱ normal overbite patients,and the long axis of the crown of the maxillary central incisor in high-angle Class Ⅱ open bite patients obviously deviates toward the labial side relative to the long axis of the root.The crown-root angle is smaller,which is beneficial to torque control or adduction movement of the anterior teeth in high-angle Class Ⅱopen bite patients.

Objective This study aimed to explore the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in patients with high-angle skeletal Class Ⅱ open bite,aiming to provide a refer-ence for clinical treatment.Methods This study was reviewed and approved by the Ethics Committee,and informed consent was obtained from the patients.CBCT images of eighty-one untreated patients(40 anterior open bite patients and 41 normal overbite patients)with high-angle skeletal Class Ⅱ malocclusion were selected before treatment.Dolphin software was used to study the root length of maxillary and mandibular anterior teeth and central incisor crown-root mor-phology,and the differences between the two groups were analyzed.Results There was no statistical significance in the root length of maxillary lateral incisor and canine between the open bite group and the normal overbite group,signifi-cant differences were found in the root length of maxillary central incisor(11.12±1.37)mm、mandibular central inci-sor(10.15±1.09)mm,mandibular lateral incisor(11.27±1.15)mm and mandibular canine(12.81±1.48)mm be-tween the open bite group and the normal overbite group(P＜0.05).On the other hand,the two groups were significant-ly different in crown-root morphology of the maxillary central incisor(1.10°±3.62° vs.4.53°±2.30°,P＜0.01)but not in the mandibular central incisor.Conclusion The root length of the maxillary central incisor,mandibular central inci-sor,mandibular lateral incisor,mandibular canine in high-angle Class Ⅱ open bite patients is shorter than that in high-angle Class Ⅱ normal overbite patients,and the long axis of the crown of the maxillary central incisor in high-angle Class Ⅱ open bite patients obviously deviates toward the labial side relative to the long axis of the root.The crown-root angle is smaller,which is beneficial to torque control or adduction movement of the anterior teeth in high-angle Class Ⅱopen bite patients.

Objective This study aimed to explore the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in patients with high-angle skeletal Class Ⅱ open bite,aiming to provide a refer-ence for clinical treatment.Methods This study was reviewed and approved by the Ethics Committee,and informed consent was obtained from the patients.CBCT images of eighty-one untreated patients(40 anterior open bite patients and 41 normal overbite patients)with high-angle skeletal Class Ⅱ malocclusion were selected before treatment.Dolphin software was used to study the root length of maxillary and mandibular anterior teeth and central incisor crown-root mor-phology,and the differences between the two groups were analyzed.Results There was no statistical significance in the root length of maxillary lateral incisor and canine between the open bite group and the normal overbite group,signifi-cant differences were found in the root length of maxillary central incisor(11.12±1.37)mm、mandibular central inci-sor(10.15±1.09)mm,mandibular lateral incisor(11.27±1.15)mm and mandibular canine(12.81±1.48)mm be-tween the open bite group and the normal overbite group(P＜0.05).On the other hand,the two groups were significant-ly different in crown-root morphology of the maxillary central incisor(1.10°±3.62° vs.4.53°±2.30°,P＜0.01)but not in the mandibular central incisor.Conclusion The root length of the maxillary central incisor,mandibular central inci-sor,mandibular lateral incisor,mandibular canine in high-angle Class Ⅱ open bite patients is shorter than that in high-angle Class Ⅱ normal overbite patients,and the long axis of the crown of the maxillary central incisor in high-angle Class Ⅱ open bite patients obviously deviates toward the labial side relative to the long axis of the root.The crown-root angle is smaller,which is beneficial to torque control or adduction movement of the anterior teeth in high-angle Class Ⅱopen bite patients.

Objective This study aimed to explore the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in patients with high-angle skeletal Class Ⅱ open bite,aiming to provide a refer-ence for clinical treatment.Methods This study was reviewed and approved by the Ethics Committee,and informed consent was obtained from the patients.CBCT images of eighty-one untreated patients(40 anterior open bite patients and 41 normal overbite patients)with high-angle skeletal Class Ⅱ malocclusion were selected before treatment.Dolphin software was used to study the root length of maxillary and mandibular anterior teeth and central incisor crown-root mor-phology,and the differences between the two groups were analyzed.Results There was no statistical significance in the root length of maxillary lateral incisor and canine between the open bite group and the normal overbite group,signifi-cant differences were found in the root length of maxillary central incisor(11.12±1.37)mm、mandibular central inci-sor(10.15±1.09)mm,mandibular lateral incisor(11.27±1.15)mm and mandibular canine(12.81±1.48)mm be-tween the open bite group and the normal overbite group(P＜0.05).On the other hand,the two groups were significant-ly different in crown-root morphology of the maxillary central incisor(1.10°±3.62° vs.4.53°±2.30°,P＜0.01)but not in the mandibular central incisor.Conclusion The root length of the maxillary central incisor,mandibular central inci-sor,mandibular lateral incisor,mandibular canine in high-angle Class Ⅱ open bite patients is shorter than that in high-angle Class Ⅱ normal overbite patients,and the long axis of the crown of the maxillary central incisor in high-angle Class Ⅱ open bite patients obviously deviates toward the labial side relative to the long axis of the root.The crown-root angle is smaller,which is beneficial to torque control or adduction movement of the anterior teeth in high-angle Class Ⅱopen bite patients.

Objective This study aimed to explore the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in patients with high-angle skeletal Class Ⅱ open bite,aiming to provide a refer-ence for clinical treatment.Methods This study was reviewed and approved by the Ethics Committee,and informed consent was obtained from the patients.CBCT images of eighty-one untreated patients(40 anterior open bite patients and 41 normal overbite patients)with high-angle skeletal Class Ⅱ malocclusion were selected before treatment.Dolphin software was used to study the root length of maxillary and mandibular anterior teeth and central incisor crown-root mor-phology,and the differences between the two groups were analyzed.Results There was no statistical significance in the root length of maxillary lateral incisor and canine between the open bite group and the normal overbite group,signifi-cant differences were found in the root length of maxillary central incisor(11.12±1.37)mm、mandibular central inci-sor(10.15±1.09)mm,mandibular lateral incisor(11.27±1.15)mm and mandibular canine(12.81±1.48)mm be-tween the open bite group and the normal overbite group(P＜0.05).On the other hand,the two groups were significant-ly different in crown-root morphology of the maxillary central incisor(1.10°±3.62° vs.4.53°±2.30°,P＜0.01)but not in the mandibular central incisor.Conclusion The root length of the maxillary central incisor,mandibular central inci-sor,mandibular lateral incisor,mandibular canine in high-angle Class Ⅱ open bite patients is shorter than that in high-angle Class Ⅱ normal overbite patients,and the long axis of the crown of the maxillary central incisor in high-angle Class Ⅱ open bite patients obviously deviates toward the labial side relative to the long axis of the root.The crown-root angle is smaller,which is beneficial to torque control or adduction movement of the anterior teeth in high-angle Class Ⅱopen bite patients.

Objective This study aimed to explore the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in patients with high-angle skeletal Class Ⅱ open bite,aiming to provide a refer-ence for clinical treatment.Methods This study was reviewed and approved by the Ethics Committee,and informed consent was obtained from the patients.CBCT images of eighty-one untreated patients(40 anterior open bite patients and 41 normal overbite patients)with high-angle skeletal Class Ⅱ malocclusion were selected before treatment.Dolphin software was used to study the root length of maxillary and mandibular anterior teeth and central incisor crown-root mor-phology,and the differences between the two groups were analyzed.Results There was no statistical significance in the root length of maxillary lateral incisor and canine between the open bite group and the normal overbite group,signifi-cant differences were found in the root length of maxillary central incisor(11.12±1.37)mm、mandibular central inci-sor(10.15±1.09)mm,mandibular lateral incisor(11.27±1.15)mm and mandibular canine(12.81±1.48)mm be-tween the open bite group and the normal overbite group(P＜0.05).On the other hand,the two groups were significant-ly different in crown-root morphology of the maxillary central incisor(1.10°±3.62° vs.4.53°±2.30°,P＜0.01)but not in the mandibular central incisor.Conclusion The root length of the maxillary central incisor,mandibular central inci-sor,mandibular lateral incisor,mandibular canine in high-angle Class Ⅱ open bite patients is shorter than that in high-angle Class Ⅱ normal overbite patients,and the long axis of the crown of the maxillary central incisor in high-angle Class Ⅱ open bite patients obviously deviates toward the labial side relative to the long axis of the root.The crown-root angle is smaller,which is beneficial to torque control or adduction movement of the anterior teeth in high-angle Class Ⅱopen bite patients.

Objective This study aimed to explore the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in patients with high-angle skeletal Class Ⅱ open bite,aiming to provide a refer-ence for clinical treatment.Methods This study was reviewed and approved by the Ethics Committee,and informed consent was obtained from the patients.CBCT images of eighty-one untreated patients(40 anterior open bite patients and 41 normal overbite patients)with high-angle skeletal Class Ⅱ malocclusion were selected before treatment.Dolphin software was used to study the root length of maxillary and mandibular anterior teeth and central incisor crown-root mor-phology,and the differences between the two groups were analyzed.Results There was no statistical significance in the root length of maxillary lateral incisor and canine between the open bite group and the normal overbite group,signifi-cant differences were found in the root length of maxillary central incisor(11.12±1.37)mm、mandibular central inci-sor(10.15±1.09)mm,mandibular lateral incisor(11.27±1.15)mm and mandibular canine(12.81±1.48)mm be-tween the open bite group and the normal overbite group(P＜0.05).On the other hand,the two groups were significant-ly different in crown-root morphology of the maxillary central incisor(1.10°±3.62° vs.4.53°±2.30°,P＜0.01)but not in the mandibular central incisor.Conclusion The root length of the maxillary central incisor,mandibular central inci-sor,mandibular lateral incisor,mandibular canine in high-angle Class Ⅱ open bite patients is shorter than that in high-angle Class Ⅱ normal overbite patients,and the long axis of the crown of the maxillary central incisor in high-angle Class Ⅱ open bite patients obviously deviates toward the labial side relative to the long axis of the root.The crown-root angle is smaller,which is beneficial to torque control or adduction movement of the anterior teeth in high-angle Class Ⅱopen bite patients.

Objective:To explore the risk factors for lymphoproliferative disorders (PTLD) in children with thalassemia major (TM) after allogeneic hematopoietic stem cell transplantation (allo-HSCT).Methods:This was a retrospective case-control study.A total of 482 children with TM who underwent allo-HSCT at Shenzhen Children′s Hospital between January 2020 and December 2022 were selected and classified into the PTLD and non-PTLD groups according to the occurrence of PTLD.The risk factors for PTLD after allo-HSCT in children with TM were analyzed, and the diagnostic efficiency of relevant risk factors for PTLD was analyzed by receiver operating characteristic (ROC) curve.Results:A total of 25 out of 482 patients (5.2%, 25/482) developed PTLD about 114 (54-271) days after allo-HSCT.Among them, 12 cases (12/25, 48.0%) occurred within 100 days, and 22 cases (22/25, 88.0%) occurred within 1 year after allo-HSCT.Univariate analysis showed that there were significant differences in gender composition, type of transplant donor, number of natural killer cells and B lymphocytes in peripheral blood at 30 days after allo-HSCT, positive rate of plasma Epstein-Barr virus deoxyribonucleic acid (EBV-DNA) and incidence rate of acute graft-versus-host disease (aGVHD) between the 2 groups (all P<0.05).Multivariate Logistic regression analysis showed that female ( OR=3.196, 95% CI: 1.144-8.929), positive plasma EBV-DNA ( OR=17.523, 95% CI: 5.449-56.344) and aGVHD ( OR=3.156, 95% CI: 1.161-8.575) were independent risk factors for PTLD after allo-HSCT in TM children (all P<0.05).The ROC curve analysis showed that positive plasma EBV-DNA had an excellent accuracy in predicting the occurrence of PTLD after allo-HSCT (sensitivity was 0.796, specificity was 0.800, area under the curve was 0.803).If combined with aGVHD and gender, the area under the curve for the prediction of PTLD increased to 0.831. Conclusions:Female, positive plasma EBV-DNA and aGVHD are independent risk factors for PTLD after allo-HSCT in children with TM.It provides useful early warnings for the prediction and prevention of PTLD.