BACKGROUND:Research has found that human umbilical cord blood platelet rich plasma and human umbilical cord blood derived mesenchymal stem cells have certain therapeutic effects on thin endometrium.However,there are currently no reports on the study of human umbilical cord blood mononuclear cells on thin endometrium,and there is a lack of relevant research comparing the three.OBJECTIVE:To explore the effects and mechanisms of human umbilical cord blood platelet rich plasma,monocytes,and mesenchymal stem cells in repairing thin endometrium in rats.METHODS:Sixty female SPF grade SD rats were randomly divided into sham operation group,model group,human umbilical cord blood platelet rich plasma group,human umbilical cord blood mononuclear cell group,and human umbilical cord blood derived mesenchymal stem cell group,with 12 rats in each group.The sham operation group received 0.5 mL physiological saline injection into the uterine horn,followed by 0.5 mL of PBS infusion after 5 minutes;The model group,human umbilical cord blood platelet rich plasma group,human umbilical cord blood mononuclear cell group,and human umbilical cord blood derived mesenchymal stem cell group were injected with 0.5 mL of 95％ethanol by volume.After 5 minutes,the remaining ethanol was aspirated and washed twice with physiological saline.Then,0.5 mL of PBS,human umbilical cord blood platelet rich plasma,human umbilical cord blood mononuclear cells(1×107 cells/mL),and human umbilical cord blood derived mesenchymal stem cells(1×107 cells/mL)were perfused separately.During the third normal estrus cycle after reperfusion,organs,tissues and serum were collected for testing of relevant indicators.RESULTS AND CONCLUSION:(1)The macroscopic view of uterine tissue,hematoxylin eosin staining and Masson staining results:the sham operation group had intact structure,moderate endometrial thickness,and clear vascular structure.Compared with the sham operation group,the model group showed uterine atrophy,incomplete structure,significantly reduced endometrial thickness and glandular quantity,disordered vascular structure,and increased fibrosis.Compared with the model group,after treatment with human umbilical cord blood derivatives,the size,structure,and endometrial thickness of the uterus were restored(all P＜0.01),and fibrosis was reduced,with the most significant recovery observed in the human umbilical cord blood mononuclear cell group.The increase in glandular quantity was most significant in the human umbilical cord blood platelet rich plasma group(P＜0.000 1).(2)The immunohistochemistry and immunofluorescence results of uterine tissue showed that compared with the sham operation group,the expression levels of cell proliferation related indicators such as keratin 9 and vimentin,endometrial receptivity related indicators such as leukemia inhibitory factor and integrin αyβ3,platelet endothelial cell adhesion molecule,basic fibroblast growth factor,and vascular endothelial growth factor were all reduced in the model group(all P＜0.05).Compared with the model group,the above indicators were significantly increased after treatment with human umbilical cord blood derivatives.Comparison of human umbilical cord blood derivatives among groups showed that keratin 9 and vascular endothelial growth factor protein:human umbilical cord blood mononuclear cell group＞human umbilical cord blood derived mesenchymal stem cell group＞human umbilical cord blood platelet rich plasma group;Wave shaped protein and leukemia inhibitory factor protein:human umbilical cord blood derived mesenchymal stem cell group＞human umbilical cord blood mononuclear cell group＞human umbilical cord blood platelet rich plasma group;Integrin αyβ3 protein:human umbilical cord blood platelet rich plasma group＞human umbilical cord blood derived mesenchymal stem cell group＞human umbilical cord blood mononuclear cell group;Platelet endothelial cell adhesion molecule protein:human umbilical cord blood platelet rich plasma group＞human umbilical cord blood mononuclear cell group＞human umbilical cord blood derived mesenchymal stem cell group;Basic fibroblast growth factor protein:human umbilical cord blood mononuclear cell group＞human umbilical cord blood platelet rich plasma group＞human umbilical cord blood derived mesenchymal stem cell group.(3)Western blot analysis showed that compared with the sham operation group,the protein levels of interleukin-6,interleukin-1β,and tumor necrosis factor alpha in the model group were significantly increased(all P＜0.001),and their expression levels decreased after treatment(all P＜0.05).(4)ELISA assay showed that compared with the sham operation group,the model group had lower levels of anti Mullerian hormone,estradiol,and progesterone,and increased levels of follicle stimulating hormone and luteinizing hormone(except for luteinizing hormone,all P＜0.05).After treatment,there was a certain degree of recovery in the levels of sex hormones and anti Mullerian hormones.(5)Fertility experiments showed that compared with the sham operation group,the model group had an increase in conception time and a significant decrease in litter size(all P＜0.05).After treatment with human umbilical cord blood derivatives,the litter size of all three groups increased(P＜0.05),and no significant differences were found between the groups.This study preliminarily reveals that human umbilical cord blood mononuclear cells have a certain therapeutic effect on thin endometrium,and human umbilical cord blood platelet rich plasma,human umbilical cord blood mononuclear cells,and human umbilical cord blood derived mesenchymal stem cells have different advantages and differences in improving endometrial regeneration function,endometrial receptivity,angiogenesis,inflammation regulation,and improving pregnancy outcomes in thin endometrium.

BACKGROUND:Research has found that human umbilical cord blood platelet rich plasma and human umbilical cord blood derived mesenchymal stem cells have certain therapeutic effects on thin endometrium.However,there are currently no reports on the study of human umbilical cord blood mononuclear cells on thin endometrium,and there is a lack of relevant research comparing the three.OBJECTIVE:To explore the effects and mechanisms of human umbilical cord blood platelet rich plasma,monocytes,and mesenchymal stem cells in repairing thin endometrium in rats.METHODS:Sixty female SPF grade SD rats were randomly divided into sham operation group,model group,human umbilical cord blood platelet rich plasma group,human umbilical cord blood mononuclear cell group,and human umbilical cord blood derived mesenchymal stem cell group,with 12 rats in each group.The sham operation group received 0.5 mL physiological saline injection into the uterine horn,followed by 0.5 mL of PBS infusion after 5 minutes;The model group,human umbilical cord blood platelet rich plasma group,human umbilical cord blood mononuclear cell group,and human umbilical cord blood derived mesenchymal stem cell group were injected with 0.5 mL of 95％ethanol by volume.After 5 minutes,the remaining ethanol was aspirated and washed twice with physiological saline.Then,0.5 mL of PBS,human umbilical cord blood platelet rich plasma,human umbilical cord blood mononuclear cells(1×107 cells/mL),and human umbilical cord blood derived mesenchymal stem cells(1×107 cells/mL)were perfused separately.During the third normal estrus cycle after reperfusion,organs,tissues and serum were collected for testing of relevant indicators.RESULTS AND CONCLUSION:(1)The macroscopic view of uterine tissue,hematoxylin eosin staining and Masson staining results:the sham operation group had intact structure,moderate endometrial thickness,and clear vascular structure.Compared with the sham operation group,the model group showed uterine atrophy,incomplete structure,significantly reduced endometrial thickness and glandular quantity,disordered vascular structure,and increased fibrosis.Compared with the model group,after treatment with human umbilical cord blood derivatives,the size,structure,and endometrial thickness of the uterus were restored(all P＜0.01),and fibrosis was reduced,with the most significant recovery observed in the human umbilical cord blood mononuclear cell group.The increase in glandular quantity was most significant in the human umbilical cord blood platelet rich plasma group(P＜0.000 1).(2)The immunohistochemistry and immunofluorescence results of uterine tissue showed that compared with the sham operation group,the expression levels of cell proliferation related indicators such as keratin 9 and vimentin,endometrial receptivity related indicators such as leukemia inhibitory factor and integrin αyβ3,platelet endothelial cell adhesion molecule,basic fibroblast growth factor,and vascular endothelial growth factor were all reduced in the model group(all P＜0.05).Compared with the model group,the above indicators were significantly increased after treatment with human umbilical cord blood derivatives.Comparison of human umbilical cord blood derivatives among groups showed that keratin 9 and vascular endothelial growth factor protein:human umbilical cord blood mononuclear cell group＞human umbilical cord blood derived mesenchymal stem cell group＞human umbilical cord blood platelet rich plasma group;Wave shaped protein and leukemia inhibitory factor protein:human umbilical cord blood derived mesenchymal stem cell group＞human umbilical cord blood mononuclear cell group＞human umbilical cord blood platelet rich plasma group;Integrin αyβ3 protein:human umbilical cord blood platelet rich plasma group＞human umbilical cord blood derived mesenchymal stem cell group＞human umbilical cord blood mononuclear cell group;Platelet endothelial cell adhesion molecule protein:human umbilical cord blood platelet rich plasma group＞human umbilical cord blood mononuclear cell group＞human umbilical cord blood derived mesenchymal stem cell group;Basic fibroblast growth factor protein:human umbilical cord blood mononuclear cell group＞human umbilical cord blood platelet rich plasma group＞human umbilical cord blood derived mesenchymal stem cell group.(3)Western blot analysis showed that compared with the sham operation group,the protein levels of interleukin-6,interleukin-1β,and tumor necrosis factor alpha in the model group were significantly increased(all P＜0.001),and their expression levels decreased after treatment(all P＜0.05).(4)ELISA assay showed that compared with the sham operation group,the model group had lower levels of anti Mullerian hormone,estradiol,and progesterone,and increased levels of follicle stimulating hormone and luteinizing hormone(except for luteinizing hormone,all P＜0.05).After treatment,there was a certain degree of recovery in the levels of sex hormones and anti Mullerian hormones.(5)Fertility experiments showed that compared with the sham operation group,the model group had an increase in conception time and a significant decrease in litter size(all P＜0.05).After treatment with human umbilical cord blood derivatives,the litter size of all three groups increased(P＜0.05),and no significant differences were found between the groups.This study preliminarily reveals that human umbilical cord blood mononuclear cells have a certain therapeutic effect on thin endometrium,and human umbilical cord blood platelet rich plasma,human umbilical cord blood mononuclear cells,and human umbilical cord blood derived mesenchymal stem cells have different advantages and differences in improving endometrial regeneration function,endometrial receptivity,angiogenesis,inflammation regulation,and improving pregnancy outcomes in thin endometrium.

Objective: This study investigated the effect of applying different torque values on the sagittal displacement tendency of mandibular incisors during intrusion using clear aligners, with the aim of providing a reference for achieving true vertical intrusion (intrusion without labiolingual movement) of mandibular incisors in clear aligner therapy. Methods: This study was approved by the institutional ethics committee. A volunteer with an incisor mandibular plane angle of 94° was selected. Using cone-beam computed tomography and intraoral scan data, a high-precision three-dimensional finite element model was established. An intrusion amount of 0.2 mm was set for the mandibular incisors, and four simulation groups were defined by applying 0°, 1°, 2°, and 3° of root labial torque. The displacement tendency of the incisors and the stress distribution within the periodontal ligament were analyzed. Results: When 0° of root labial torque was applied, the mandibular incisors exhibited intrusion accompanied by crown-labial, root-lingual inclination. When 1°-3° of root labial torque was applied, the mandibular incisors exhibited intrusion accompanied by the inclination gradually shifted from crown-labial, root-lingual towards crown-lingual, root-labial. Based on the line graph of sagittal displacement, the central incisors and lateral incisors approximated true vertical intrusion when 1.8° and 2.5° of root labial torque was applied, respectively. The mandibular canines consistently exhibited extrusion accompanied by labial crown inclination. Stress within the periodontal ligament of the incisors and canines was primarily concentrated at the root apex and cervical region. After applying root labial torque, the area of stress concentration in the incisors cervical periodontal ligament shifted from the labial side to the lingual side. The stress in the periodontal ligament at the cervical region of the canines is predominantly concentrated on the labial side. Conclusion Applying appropriate torque control during mandibular incisor intrusion with clear aligners facilitates true vertical intrusion, thereby enhancing the efficiency of the intrusion.

OBJECTIVE To evaluate the cost-effectiveness of finerenone combined with standard of care （SoC） in the treatment of heart failure with mildly reduced ejection fraction （HFmrEF） or preserved ejection fraction （HFpEF）. METHODS Based on a phase Ⅲ clinical trial， a Markov model was constructed from the perspective of China’s healthcare system to compare the treatment outcomes of finerenone combined with SoC regimen versus SoC regimen alone in the treatment of different cardiac functional statuses of HFmrEF/HFpEF. Using quality-adjusted life year （QALY） as the health output index， 3 times China’s per capita GDP in 2023 as the willingness-to-pay （WTP） threshold， a simulation was conducted with a 3-month cycle length and a 10- year time horizon， incorporating an annual discount rate of 5%. The dynamic changes across various stages of HFmrEF/HFpEF treated with finerenone combined with SoC versus SoC alone were simulated to evaluate the long-term effectiveness and costs of the two treatment strategies. Additionally， one-way sensitivity analysis and probabilistic sensitivity analysis were performed， to test the robustness of the results. RESULTS The incremental cost-effectiveness ratio （ICER） of the finerenone combined with SoC regimen versus SoC regimen alone was 179 504.75 yuan/QALY， which was below the WTP threshold set in this study， indicating that the finerenone combined with SoC regimen possessed certain economic advantages. The results of one-way sensitivity analysis showed that the utility value of NYHA Ⅱ status， the drug price of finerenone， the discount rate， and the probability of hospital transfer for both groups had a great influence on ICER， but did not affect the robustness of the model. The probabilistic sensitivity analysis also confirmed the robustness of the model. CONCLUSIONS Under the WTP threshold set in this study， finerenone combined with SoC is cost-effective in the treatment of HFmrEF/HFpEF， compared with the SoC regimen.

Objective To investigate the expression of forkhead box P3(Foxp3)in peripheral blood of children with bronchial asthma and its relationship with airway hyper-responsiveness and body allergy.Methods A total of 80 children with bronchial asthma treated in the Affiliated Hospital of Yangzhou University from July 2024 to June 2025 were selected as experimental group,and 47 health-y children with physical examinations in the same period were selected as control group.Airway hy-per-responsiveness indicators(respiratory resistance,bronchial stimulant reaction threshold,and re-sistance increase slope),body allergy indicators[serum immunoglobulin E(IgE),eosinophil cationic protein(ECP),and eosinophil count(EOS)],pulmonary function indicators[peak expiratory flow(PEF),forced expiratory volume in the first second(FEV,),forced vital capacity(FVC),and the ratio of forced expiratory volume in the first second to forced vital capacity(FEV1/FVC)],and the expression level of Foxp3 in peripheral blood were compared between the two groups.Pearson corre-lation analysis was used to explore the correlations of Foxp3 with airway hyper-responsiveness and body allergy.Results The respiratory resistance and resistance increase slope in the control group were significantly lower than those in the experimental group,while the reaction threshold was signif-icantly higher than that in the experimental group(P＜0.05).The levels of IgE,ECP and EOS in the experimental group were significantly higher than those in the control group(P＜0.05).The FEV1,FVC,PEF,and FEV1/FVC in the experimental group were significantly lower than those in the control group(P＜0.05).The expression level of Foxp3 in the experimental group was(3.04±0.22),which was significantly lower than(4.22±0.41)in the control group(P＜0.05).Foxp3 was significantly correlated with respiratory resistance(r=-0.700,P＜0.001),reaction thresh-old(r=0.704,P＜0.001),resistance increase slope(r=-0.842,P＜0.001),IgE(r=0.864,P＜0.001),ECP(r=-0.684,P＜0.001),and EOS(r=-0.854,P＜0.001).Con-clusion The decreased Foxp3 in peripheral blood in children with bronchial asthma is associated with aggravated airway hyper-responsiveness and body allergy,suggesting that Foxp3 may be in-volved in the pathogenesis of bronchial asthma.

BACKGROUND:The utilization of miniscrews for assisting in molar distalization with clear aligners is a commonly adopted clinical approach.However,treatment outcomes may be influenced by the implantation position of miniscrew and the hooks in various tooth location.OBJECTIVE:To analyze the biomechanical effects of hooks at different tooth positions and the assistance of buccal and palatal miniscrews in distalizing molars with clear aligners by using the finite element method.METHODS:By integrating volunteer cone beam CT and Itero intraoral scan data,high-precision finite element models were constructed to simulate the combined use of miniscrews and hooks to assist in the distalization of the maxillary first and second molars with clear aligners,aiming for a designed distalization magnitude of 0.2 mm.Four conditions were established based on the placement of buccal or palatal miniscrews,as well as the located of hooks at the canine or first premolar.The buccal anchorage screw was used in combination with hooks on the buccal side of the canine;the buccal anchorage screw was used in combination with hooks on the buccal side of the first premolar;the palatal anchorage screw was used in combination with hooks on the lingual side of the canine,and the palatal anchorage screw was used in combination with hooks on the lingual side of the first premolar.Analysis using ANSYS software was conducted to evaluate the three-dimensional displacement trends of maxillary teeth and the maximum equivalent stress on the periodontal ligament under each condition.RESULTS AND CONCLUSION:(1)Regardless of whether hooks were placed on canines or first premolars,palatal miniscrews had been shown to enhance the distal movement of maxillary molars and reduce the mesial movement of premolars as well as the labial tipping tendency of anterior teeth,compared to buccal miniscrews.The maximum equivalent stress in the periodontal ligament of molars was increased,while that of anterior teeth was decreased.(2)Regardless of whether the miniscrews were located on the buccal or palatal side,compared with hooks at the first premolar,when hooks were done at the canine,the labial inclination trend of the anterior teeth was reduced,the distal movement of the molars was reduced,the mesial movement of the premolars was increased,and the maximum equivalent stress of the molar and the periodontal membrane of the anterior teeth was reduced.(3)Regardless of whether miniscrews were located on the buccal or palatal side,and the hooks were located on the canine or the first premolar,the molar could not achieve overall movement.(4)The results show that clear aligner combined with palatal miniscrews and hooks at the first premolar are more conducive to improving the efficiency of maxillary molar distalization,but attention should be paid to protecting the anterior tooth miniscrews and molar torque control;clear aligner combined with palatal miniscrews and hooks at the canine is more conducive to reducing the labial tipping tendency of anterior teeth,but the efficiency of molar distalization will be relatively reduced.

Objective:To introduce the research and innovations around the application of aquatic rehabilitation techniques in the treatment of lumbago, and to summarize specific methods and applications in aeromedicine. Literature resource and selection Literature on the prevention and treatment of lumbago using aquatic rehabilitation techniques as well as on the rehabilitation of lumbago in pilots was retrieved and selected. Literature quotation Sixty-one references were cited. Literature synthesis Aquatic rehabilitation techniques can be classified into shower therapy, immersion therapy, and aquatic exercise therapy according to treatment regimens. Among them, immersion therapy and aquatic exercise therapy are commonly used in the treatment of lumbago. Aquatic rehabilitation techniques can effectively alleviate patients′ lumbago, improve their functional disorders, and enhance their quality of life. Prior to aquatic therapy, patients with lumbago need to have their motor function assessed to tailor the treatment protocol based on diagnostic findings and specific therapeutic objectives. Aquatic rehabilitation techniques, when used to prevent and treat lumbago in pilots under convalescence, are not only more effective than land-based training, but also more accessible to pilots due to their comfort and compliance. Many of our military rehabilitation and convalescent centers in China have integrated modern aquatic rehabilitation techniques into rehabilitation treatment by drawing on their rich water resources so as to improve the physical and mental health, social adaptability and military adaptability of pilots. Conclusions:When used for the prevention and treatment of lumbago, aquatic rehabilitation techniques are highly effective, safe and enjoyable, so they should be made more accessible to pilots during convalescence.

Objective:To investigate the ocular pathogen spectrum and drug sensitivity characteristics of patients to be diagnosed with infectious keratitis within 10 years in two tertiary hospitals in Nantong City, Jiangsu Province, eastern China.Methods:A cross-sectional study was conducted.Microbial culture specimens from consecutive 1 404 patients with suspected infectious keratitis admitted to the Department of Ophthalmology at the First People's Hospital of Nantong City and Nantong University Affiliated Hospital from January 2014 to October 2023 were collected.The patients' general data, etiology and drug sensitivity test results were analyzed.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Nantong First People's Hospital (No.2021KT273) and Nantong University Affiliated Hospital (No.2019-K068).Results:Among 1 404 patients with suspected infectious keratitis, the positive rate of microbial culture was 37.04%(520/1 404).A total of 537 strains were isolated and cultured, with fungi accounting for 69.09%(371/537) and bacteria accounting for 30.91%(166/537).The common bacterial genera in fungal keratitis were Fusarium (47.17%, 175/371), Alternaria (15.90%, 59/371), Aspergillus (14.56%, 54/371), Certospora (10.78%, 40/371) and Penicillium (3.50%, 13/371).The annual composition ratio of Fusarium showed a downward trend, while Certospora showed an upward trend.The common bacteria in bacterial keratitis were Staphylococcus epidermidis (24.10%, 40/166), Streptococcus pneumoniae (17.47%, 29/166), Pseudomonas aeruginosa (13.25%, 22/166), Staphylococcus aureus (6.63%, 11/166) and Corynebacterium macginleyi (4.22%, 7/166).The annual composition ratio of Pseudomonas aeruginosa showed an increasing trend.The resistance rates of gram-positive bacteria to levofloxacin and vancomycin were 36.26% and 0% respectively, and the resistance rates of gram-negative bacteria to aminoglycosides and ceftazidime were <10%.A total of 61 bacterial strains (40.94%) were multi-drug resistant. Conclusions:Fusarium is common in fungal keratitis, and Corynebacterium macginleyi in bacterial keratitis may be a microbial feature in Nantong City.Levofloxacin may no longer be suitable as a first-line antibiotic for topical ocular use.

Objective:To investigate the ocular pathogen spectrum and drug sensitivity characteristics of patients to be diagnosed with infectious keratitis within 10 years in two tertiary hospitals in Nantong City, Jiangsu Province, eastern China.Methods:A cross-sectional study was conducted.Microbial culture specimens from consecutive 1 404 patients with suspected infectious keratitis admitted to the Department of Ophthalmology at the First People's Hospital of Nantong City and Nantong University Affiliated Hospital from January 2014 to October 2023 were collected.The patients' general data, etiology and drug sensitivity test results were analyzed.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Nantong First People's Hospital (No.2021KT273) and Nantong University Affiliated Hospital (No.2019-K068).Results:Among 1 404 patients with suspected infectious keratitis, the positive rate of microbial culture was 37.04%(520/1 404).A total of 537 strains were isolated and cultured, with fungi accounting for 69.09%(371/537) and bacteria accounting for 30.91%(166/537).The common bacterial genera in fungal keratitis were Fusarium (47.17%, 175/371), Alternaria (15.90%, 59/371), Aspergillus (14.56%, 54/371), Certospora (10.78%, 40/371) and Penicillium (3.50%, 13/371).The annual composition ratio of Fusarium showed a downward trend, while Certospora showed an upward trend.The common bacteria in bacterial keratitis were Staphylococcus epidermidis (24.10%, 40/166), Streptococcus pneumoniae (17.47%, 29/166), Pseudomonas aeruginosa (13.25%, 22/166), Staphylococcus aureus (6.63%, 11/166) and Corynebacterium macginleyi (4.22%, 7/166).The annual composition ratio of Pseudomonas aeruginosa showed an increasing trend.The resistance rates of gram-positive bacteria to levofloxacin and vancomycin were 36.26% and 0% respectively, and the resistance rates of gram-negative bacteria to aminoglycosides and ceftazidime were <10%.A total of 61 bacterial strains (40.94%) were multi-drug resistant. Conclusions:Fusarium is common in fungal keratitis, and Corynebacterium macginleyi in bacterial keratitis may be a microbial feature in Nantong City.Levofloxacin may no longer be suitable as a first-line antibiotic for topical ocular use.

BACKGROUND:The utilization of miniscrews for assisting in molar distalization with clear aligners is a commonly adopted clinical approach.However,treatment outcomes may be influenced by the implantation position of miniscrew and the hooks in various tooth location.OBJECTIVE:To analyze the biomechanical effects of hooks at different tooth positions and the assistance of buccal and palatal miniscrews in distalizing molars with clear aligners by using the finite element method.METHODS:By integrating volunteer cone beam CT and Itero intraoral scan data,high-precision finite element models were constructed to simulate the combined use of miniscrews and hooks to assist in the distalization of the maxillary first and second molars with clear aligners,aiming for a designed distalization magnitude of 0.2 mm.Four conditions were established based on the placement of buccal or palatal miniscrews,as well as the located of hooks at the canine or first premolar.The buccal anchorage screw was used in combination with hooks on the buccal side of the canine;the buccal anchorage screw was used in combination with hooks on the buccal side of the first premolar;the palatal anchorage screw was used in combination with hooks on the lingual side of the canine,and the palatal anchorage screw was used in combination with hooks on the lingual side of the first premolar.Analysis using ANSYS software was conducted to evaluate the three-dimensional displacement trends of maxillary teeth and the maximum equivalent stress on the periodontal ligament under each condition.RESULTS AND CONCLUSION:(1)Regardless of whether hooks were placed on canines or first premolars,palatal miniscrews had been shown to enhance the distal movement of maxillary molars and reduce the mesial movement of premolars as well as the labial tipping tendency of anterior teeth,compared to buccal miniscrews.The maximum equivalent stress in the periodontal ligament of molars was increased,while that of anterior teeth was decreased.(2)Regardless of whether the miniscrews were located on the buccal or palatal side,compared with hooks at the first premolar,when hooks were done at the canine,the labial inclination trend of the anterior teeth was reduced,the distal movement of the molars was reduced,the mesial movement of the premolars was increased,and the maximum equivalent stress of the molar and the periodontal membrane of the anterior teeth was reduced.(3)Regardless of whether miniscrews were located on the buccal or palatal side,and the hooks were located on the canine or the first premolar,the molar could not achieve overall movement.(4)The results show that clear aligner combined with palatal miniscrews and hooks at the first premolar are more conducive to improving the efficiency of maxillary molar distalization,but attention should be paid to protecting the anterior tooth miniscrews and molar torque control;clear aligner combined with palatal miniscrews and hooks at the canine is more conducive to reducing the labial tipping tendency of anterior teeth,but the efficiency of molar distalization will be relatively reduced.