Dental trauma is a common oral condition in children. For single-type trauma to young permanent teeth, timely treatment often results in a high survival rate for both the teeth and the pulp. However, in cases of complex dental trauma or when supernumerary teeth are impacted near the apex of the injured tooth, the prognosis is less predictable. This article reports a case of root fracture in an immature maxillary permanent central incisor combined with impacted supernumerary tooth in the apical region. After supernumerary tooth extraction and pulp revascularization therapy, the case demonstrated a good treatment outcome over a nearly 10-year follow-up period.
Child ; Humans ; Incisor/injuries* ; Maxilla ; Tooth Extraction ; Tooth Fractures/complications* ; Tooth Root/injuries* ; Tooth, Impacted/surgery* ; Tooth, Supernumerary/surgery*

Objective To explore the effects of facial asymmetry on stress distributions in temporomandibular joints (TMJs) for patients with mandibular prognathism. Methods Eight 3D maxillofacial models were established in MIMICS based on cone-beam CT of 4 mandibular prognathism patients with asymmetry and 4 mandibular prognathism patients without asymmetry. Muscle forces and boundary conditions corresponding to the unilateral occlusion (unilateral molar chewing) were applied on the models in ABAQUS. The maximum and the minimum principal stresses of TMJ were chosen for analysis. Results There were significant differences in the maximum and minimum principal stresses at the condyles between the mandibular prognathism patients with and without facial asymmetry under unilateral occlusions (P<0-05). Compared with patients without facial asymmetry, the stresses on the condyle in patients with asymmetry increased by 2-3 times, and the stresses on articular fossa increased by 5-7 times. Among the mandibular prognathism patients with asymmetry, the stresses of the ipsilateral TMJ in patients with temporomandibular disorder (TMD) were significantly higher than those in patients without TMD. Conclusions Facial asymmetry increased the stresses of the articular fossa and condyle in patients with mandibular prognathism. TMD would cause greater stresses in ipsilateral TMJ of the mandibular prognathism patient with asymmetry. Therefore, different treatment strategies should be considered for mandibular prognathism with facial asymmetry.

Objective To observe the changes of the skeletal development related cells after dihydroorotate dehydrogenase (DHODH) deficiency.Methods The DHODH expression in MC3T3-E1 cells derived from mouse calvaria osteoblast precursor cells was inhibited by specific small interfering RNAs (siRNAs),and cell proliferation,ATP production and expression levels of bone-related genes were investigated in these cells.Results After reducing the DHODH expression by using specific siRNAs,cell proliferation was inhibited and cell cycle was arrested at G1/S stage.In addition,the ATP production was reduced in whole cells,especially in mitochondria.Furthermore,the expression levels of Runt-related transcription factor 2 (Runx2) and osteocalcin (Ocn) mRNAs in the DHODH inhibition group were decreased compared with the control group.Conclusion Inhibiting DHODH protein affects the differentiation and maturation of osteoblasts.The mitochondrial dysfunction in osteoblasts may be one of causes leading to the abnormal bone formation in Miller syndrome.

ObjectiveTo study the relationship between vitamin D receptor (VDR) gene polymorphism and calcitonin receptor (CTR) gene polymorphism, and bone mineral density (BMD) of the Han nationality woman in Hebei, explore the pathogenesis of osteoporosis (OP) at the gene level.MethodsPolymorphisms of VDR gene and CTR gene were analyzed by restriction fragment length polymorphisms (RFLPs) in 60 Han nationality women in Hebei.ResultsBb genetype of VDR had lower BMD values at all sites which were measured compared with bb genetype (P<0.05); CC genetype of CTR had tendency for lower BMD values at the L1～L4 compared with CT genetype (0.05