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Background/Aims: Pediatric oral and maxillofacial surgeons have faced severe challenges in ward management due to their high risk of exposure during the COVID‐19 epidemic. The aim of this study was to analyze and summarize the treatment methods and infection prevention and control measures applied in emergency cases in the Department of Pediatric Oral and Maxillofacial Surgery, Children's Hospital of Chongqing Medical University, during the COVID‐19 epidemic. Methods: In this retrospective study, information was collected from 256 pediatric emergency patients who were treated from January 23, 2020 to August 9, 2021. The patients' data were statistically analyzed according to age, gender, disease and pathogenesis, operation time, and the main treatment applied in pediatric oral and maxillofacial emergency cases during the COVID‐19 epidemic. Results: During the epidemic period, 256 pediatric emergency patients were successfully treated. Among them, there were 170 boys and 86 girls. In all, 182 patients were diagnosed with oral or facial lacerations; 43 had jaw fractures; 26 had maxillofacial infections; and five had dento‐alveolar fractures. A total of 246 patients underwent surgery under negative pressure with level 3 protection standards. No doctors or patients infected with COVID‐19 were found throughout the stury period. Conclusions: Pediatric oral and maxillofacial emergency in‐patients mainly experienced maxillofacial trauma during the COVID‐19 epidemic, followed by infection. Effective diagnosis and treatment, and avoidance of COVID‐19 infection can be achieved by strictly following epidemic prevention and treatment procedures. [ABSTRACT FROM AUTHOR]

Objective To observe the effect of dexamethasone on the proliferation and apoptosis of embryonic palatal mesenchymal (EPM) cells, and chose a proper concentration of dexamethasone which can effect the ordinary growth of embryonic palatal mesenchymal cells. Methods The primary EPM cells were isolated and cultured in vitro, then we did biological assay. EPM cells were treated with different concentration dexamethasone (1x10-9, 1x10-8, 1x10-7 and 1x10-6 mol●L-1) respectively. The proliferation of EPM cells was evaluated using MTT method. Apoptosis was examined quantitatively with fluorescein stain. Results In the condition of blood serum's concentration at 10%, optical density step down following the raise of dexamethasone's concentration. The effect of dexamethasone got to a summit at 3 days. Inhibition rate of dexamethasone at 1x10-6 mol●L-1 was the highest. Conclusion Dexamethasone at 1x10-6 mol●L-1 can not only inhibit the growth of the EPM cells, but also will not lead to a large number of cells death. Therefore, this concentration can be used as a reference standard in future research. The most significant drug action time of dexamethason appears at the third day after administration, then the effect became weaken following the drug metabolism. [ABSTRACT FROM AUTHOR]

This study aimed to explore the effects of different types of palatal lateral excisions on the growth and development of the maxilla and dental arch, and to investigate the underlying mechanisms. A total of 112 3-week-old Sprague-Dawley (SD) male rats were randomly divided into a control and 3 experimental groups: the mucoperiosteal denudation group, the mucosal flap excision group, and the periosteum excision group. In the experimental groups, bilateral mucoperiosteal, mucosal flap and periosteum were excised respectively in the lateral one half of the palate. Four rats in each group were randomly chosen for sacrifice every two weeks. The maxilla was dissected following the excision. The widths of the maxilla and dental arch were measured and the histological phenomena were investigated at different phases. At the same time, 12 animals in each group were sequentially injected with calcein every two weeks. Three animals in each group, whose fluorescent labeling was used, were sacrificed for investigating bone formation at Week 8 following injection. (1) Each experimental group presented the constriction of the maxilla and dental arch. The upper first molars in the experimental groups inclined medially. The mucoperiosteal denudation group showed the largest degree of effect followed by the periosteum excision group. The indices of the mucosal flap excision group, which retained the structures of the periosteum layer, had the most approximate values to the control group; (2) Different histological changes among the experimental groups were detected. The fibers penetrated into the palatal bone as Sharpey’s fibers in the mucoperiosteal denudation group. The pattern of bone deposition was the bundle type. Sharpey’s fibers were not found in the mucosal flap and periosteum excision groups and the depositions of palatal bone were the lamellar type as those in the control group; (3) The rates of bone deposition in the experimental groups decreased compared with the control group. The rates in different phases were the most approximate values to those of the control group in the mucosal flap excision group, which has the same structure of periosteum as the control group. There were different effects on the growth and development of the maxilla and dental arch in different types of palatal lateral excisions. Periosteum is important for bone formation and deposition pattern. The prevention of Sharpey’s fibers forming and attaching to the palatine can effectively avert the following malformation. [ABSTRACT FROM AUTHOR]