Application of invisible orthodontic appliances in the treatment of adult skeletal malocclusions,especially in the cases requiring tooth extraction,has always been one of the challenges in invisible orthodontic technology.Our department received a 30-year-old female patient in March 2019;the patient presented with complaints of"crooked teeth and protruding mouth,"seeking orthodontic treatment to improve her facial profile.The patient had bilateral distal molar relationship,proclined maxillary and mandibular anterior teeth,and deep overjet;radiographic examination revealed an ANB angle of 6.2°,indicating a skeletal Class Ⅱ malocclusion.By extracting four first premolars and using four miniscrews,after 20 months of treatment,the extraction spaces were fully closed,the dental arch was aligned,and the occlusal relationship was favorable;the anterior teeth were retracted,the mandible showed a reverse rotation,and the soft tissue profile was significantly improved.Application of invisible orthodontic appliances in conjunction with miniscrews anchorage can achieve good three-dimensional control of tooth movement in adult extraction cases,providing a reference for clinical practitioners treating such patients.

Objective To evaluate the clinical efficacy of invisible orthodontic appliances without brackets for the distal movement of maxillary molars to improve the ability of orthodontists to predict treatment outcomes.Methods Web of Science,Cochrane Library,Embase,PubMed,Wanfang Database,CNKI Database,and VIP Database were searched for studies investigating the efficacy of invisible orthodontic appliances for distal movement of maxillary molars in adult patients and published from database inception to August 1,2023.A total of three researchers screened the studies and evaluated their quality and conducted a meta-analysis of those that met quality standards.Results This study included 13 pre-and postcontrol trials with a total sample size of 281 patients.The meta-analysis revealed no sig-nificant differences in the sagittal or vertical parameters of the jawbone after treatment when compared with those before treatment(P＞0.05).The displacement of the first molar was MD=-2.34,95％CI(-2.83,-1.85);the displacement was MD=-0.95,95％CI(-1.34,-0.56);and the inclination was MD=-2.51,95％CI(-3.56,-1.46).There was a statistically significant difference in the change in sagittal,vertical,and axial tilt of the first molar before and after treatment.After treatment,the average adduction distance of the incisors was MD=-0.82,95％CI(-1.54,-0.09),and the decrease in lip inclination was MD=-1.61,95％CI(-2.86,-0.36);these values were significantly different from those before treat-ment(P＜0.05).Conclusion Invisible orthodontic appliances can effectively move the upper molars in a distal direc-tion and control the vertical position of the molars.When the molars move further away,there is some degree of com-pression and distal tilt movement,which is beneficial for patients with high angles.The sagittal movement of incisors is beneficial for improving the patient's profile.

Objective To study the effect of ribosomal protein S13(RPS13) encoding genes on the development of mutidrug resistance (MDR) in human gastric cancer cell line. Methods RPS13 cDNA was amplified by RT-PCR. The sense and antisense eukaryotic expression vectors were constructed by DNA recombination. Gastric cancer cell line SGC7901 and Vincristine-resistant SGC7901/VCR cells were transfected with the sense and antisense recombinant vectors respectively using liposome-mediated method. RNA dot blotting assay was used to verify the changes of mRNA level in stable clones. To investigate effects of the sense, antisense vector transfection on the chemotherapeutic drug sensitivity, thiazolyl blue (MTT) cytotoxicity assay was used. Cell cycle was detected by flow cytometry (FCM). Results Whole length of RPS13 cDNA gene was amplified by RT-PCR. The sense, antisense eukaryotic expression vectors were constructed by the directed cloning of the target genes into eukaryotic expression vector pcDNA 3.1(+). RNA dot blotting assay suggested that mRNA level of the RPS13 was up-regulated in the sense recombinant vector transfected cells, and down-regulated in the antisense recombinant vector transfected cells. By MTT cytotoxicity assay, the enhanced resistance to adriamycin, 5-fluorouracil and vincristine was found in the RPS13 sense recombinant vector transfected SGC7901 cells. RPS13 antisense recombinant vector rendered SGC7901/VCR cells partially sensitive to mitomycin and vincristine. Cell cycle analysis suggested that the proportion of G1, S, and G2 cells was 47.0%, 33.2% and 19.8% respectively in up-regulated RPS13 cells; the proportion of G1, S and G2 cells was 62.9%, 1.0% and 36.1% respectively in down-regulated RPS13 cells. Conclusions RPS13 may take part in the mediation of MDR in gastric cancer cells.