Objective : To analyze the initial displacement of the upper central incisor and stress distribution of periodontal ligament under different torque values of upper incisors under the action of a four-curved auxiliary arch to provide a reliable basis for the safety of clinical application of four-curved auxiliary arches. Methods : A three-dimensional finite element model for torque control of upper anterior teeth with a homemade quadrilateral auxiliary arch was established. Four different states were analyzed: molar ligation without extraction space (group A), microimplant ligation without extraction space (group B), molar recovery with extraction space closure (group C) (the adductive traction force was set at 115 g) and microimplant recovery with extraction space closure (group D) (the adductive traction force was set at 115 g). When four types of torque (0.5 N, 1.0 N, 1.5 N, and 2.0 N) were applied. The initial displacement of upper central incisors and the stress distribution of periodontal ligament in 16 groups (A1-A4, B1-B4, C1-C4, D1-D4) were observed. Results : Under different conditions, as the strength of the four-curve auxiliary arch increases, the maxillary anterior teeth has crown labial inclination and a root lingual inclination. The displacement of the incisor tip increases with the increase in the loading force of the torque auxiliary arch, and the displacement of the incisor root apex increases as the force increases. The difference in incisor-apex displacement distance in A1-A4, B1-B4, C1-C4, D2 and D4 groups increased as the torque force increases, while the difference between the D3 group and D1 and D2 groups decreased slightly. The stress of the cervical periodontal ligament of the upper central incisor did not exceed the stress of the periodontal ligament in the following groups: A1, A2, B1, B2, B3, C1, C2, D1, and D2. The stress of the lip side of the upper central incisor did exceed the stress of the periodontal ligament in the following groups: A3, A4, B4, C3, C4, D3, and D4. In other words, when using the four-curved auxiliary arch as an implant anchorage, the force applied in the absence of extraction space should not exceed 1.5 N, and the force applied in the adduction of extraction space should not exceed 1.0 N. When using the nonimplant anchorage, the force applied in the absence of extraction space and the adduction of extraction space should not exceed 1.0 N. In addition, the range of force should not exceed the maximum stress of the periodontal ligament in the cervical region such that the effective and safe torque movement can be achieved. Under other stress conditions, the stress of the labial and cervical periodontal ligament of the upper central incisor exceeded the stress value (2.6 × 10-2MPa). The stress value of periodontal ligament was 2.6 × 10-2MPa in all groups. Conclusion A four-curved auxiliary arch has a significant effect on the upper anterior teeth, and the use of microimplants can better control root movement such that the crown of upper central incisors cannot be excessively lip inclined.

Objective: To analyze the clinical , immunological and genetic features of a child with BCL11B mutation induced neurodevelopmental disorder. Methods: The clinical data and genetic test of a child with BCL11B mutation hospitalized in the Department of Rheumatology and Immunology in Children′s Hospital of Chongqing Medical University in December 2018 were extracted and analyzed. The literature was searched with "BCL11B mutation" and "immunodeficiency 49" as key words in Chinese databases and Pubmed until January 2019 was reviewed. Results: A male patient aged 3 years and 11 months with facial dysmorphisms and delayed language and motor development was admitted due to neurodevelopmental retardation over two years. Laboratory tests showed normal human immunoglobulin (IgG 12.90 g/L, IgA 1.02 g/L, IgM 1.15 g/L, IgE 532 000 U/L), Trec (228) and proliferation of T and B cells. The lymphocyte subsets revealeda reduced percentage of B cells (0.108) but normal absolute numbers (0.574×10^-3/L), and an increased percentage (0.828) as well as absolute numbers (4.415×10^-3/L) of T cells. A heterozygous BCL11B mutation was detected by sanger sequencing, showing a de novo frameshift mutation c.1887_c.1893delCGGCGGG in exon 4. Two papers were found which were all in English, with total of 14 patients(13 patients with complete information). Thirteen mutations were reposed, including 7 frameshift, 2 nonsense, 2 missense, and 2 chromosomal rearrangements; Thirteen patients had heterozygous mutations. All patients had delayed language and motor development and facial dysplasia which were mainly hypertelorism, thin eyebrows and small palpebral fissures. Some patients had dental anomalies, ametropia and allergy, and a few were combined with immune impairment, but without overt signs of immunodeficiency. Only one patient had multisystem anomalies and profound immune deficiency. Conclusions BCL11B is essential for development of the nervous and the immune system. In this study, the de novo mutation of BCL11B gene resulted in neurodevelopmental and immunological disorders.