Objective To investigate the inhibitory effects of silencing expression ofEZH2 gene on the cell proliferation of human QBC939 cells and its mechanisms. Methods The targeting siRNA was designed and trans-fected into QBC939cells. The expressions of EZH2 mRNA and protein were detected by real-time qPCR and west-ern blotting,respectively. The ability of cellproliferationwas analyzed by MTT assay and plate clone formation assay. Cell apoptosis and cycle percentage weremeasured by flow cytometry. Cell senescence was assessed byβ-galactosi-dase dyeing.The expressions of H3K27me3,P14ARF,P16INK4a,P53,P21 and E2F1 proteinwere determined by West-ern blotting.Results Compared with the control group ,the expressions of mRNAand protein were significantly elevat-ed in experimental group. The ability of cellproliferation in the experiment group was significantly down regulated , which could also cause a rise of G1/S phase ,but not a marked variation of apoptosis rate. Silencing EZH2 would induce a obvious senescence phenotype in QBC939 cells. EZH2-siRNA transferredcould also down-regulate the expressions of H3K27me3 and E2F1 protein,while up-regulating the expressions of P14ARF,P16INK4a,P53 and P21 protein in QBC939 cells.Conclusions Silencing EZH2 could induce a significant inhibition on cell proliferation of QBC939 cells,the mechanism of which may be associated with the senescence pathway regulation.

Objective: To investigate the effect of frequently used Duraphaton preventing dental demineralization of patients with fixed orthodontic appliances. Methods: A total of 50 orthodontic patients wearing fixed appliances at Department of orthodontics, Affiliated Stomatological Hospital, Nanjing Medical University from June to December 2021 were selected as study subjects by convenient sampling method. They were then randomly divided into experimental group and control group according to random numbers. The experimental group received high-frequency fluoride treatment for unilateral maxillary lateral incisors and no treatment on the contralateral side. Meanwhile, the control group received placebo treatment for unilateral maxillary lateral incisors and no treatment on the contralateral side. Each patient was followed up for 6 months. The initial and final photographs of patients' maxillary lateral incisors were observed and scored to determine the mean demineralization progression index for each group. Results: The difference in mean demineralization progression index was statistically significant when comparing different groups(P<0.05), and the lowest incidence of demineralization was reported in the Duraphattreated group (0.960±0.465), followed respectively by the fluoride-free control group (1.213±0.713), the placebo control group (1.267±0.720) and the placebo treatment group (1.307±0.713). Conclusion High frequency use of Duraphatis is effective in reducing the incidence of demineralization in patients with fixed orthodontic appliances.

Objective To investigate the differences in treatment experience and quality of life between adolescent orthodontic pa-tients using clear aligners and fixed braces.Methods A total of 104 adolescent patients were selected who underwent orthodontic treat-ment with either clear aligners or fixed braces at Nanjing Medical University Affiliated Stomatological Hospital from January 2022 to June 2022.The patients were divided into two treatment groups based on the type of orthodontic appliance,with 52 patients in each group.Within a 6-month period of using clear aligners or fixed braces,adolescent orthodontic patients were surveyed using the child oral health impact profile-short form 19(COHIP-SF19)and other individual items.The differences in mean satisfaction,quality of life,and statistical scores were compared using independent samples t-tests,while the differences in subjective responses were compared using the Wilcoxon rank-sum test.Results There were no significant differences in mean quality of life and statistical scores between the two groups,but patients in the clear aligner group reported higher satisfaction.The clear aligner group reported greater difficulty with eating,while patients with fixed braces were more likely to experience negative emotions.Additionally,there were no significant differences between the two groups in terms of adaptation time to the appliance,maintaining dental hygiene,and feeling attractive.Conclusion Patients in both groups were generally satisfied with their treatment.Adolescent orthodontic patients treated with clear a-ligners or fixed braces for at least 6 months exhibit similar overall quality of life.