Objective To investigate the clinical practice pressure and mental health of medical students with type D personality.Methods Type D Scale-14 (DS14) and Beck-Srivastava Stress Inventory (BSSI) test were applied to 371 medical students to assess the personality types and pressure.The symptom checklist 90 (SCL-90) was used to evaluate the psychological health.Results ①The detection rate of type D personality of medical students was 36.39％.②The average score in BSSI of medical students of type D personality was (99.27± 10.51),which was higher than medical students of non-type D personality (87.60± 11.37),and the difference was statistically significant (t=9.9711,P=0.0000).The medical students' score of type D personality in SCL-90 of 9 factors were all higher than medical students of non-type D personality,but the statistically significant difference were only in the score of depression,anxiety and psychosis-like symptoms (t=2.4409,P=0.0151;t=2.8662,P=0.0044;t=2.7783,P=0.0057).Conclusion In face of the same pressure of medical clinical practice,the medical students of type D personality are more likely to have a heavier psychological burden,and the college should pay special attention to the problem and try to intervene the problem,so as to reduce the pressure caused by a variety of psychological problems.

Objective This study aimed to identify PAX9 variants in non-syndromic tooth agenesis families of Chi-na,as well as to analyze the genotype-phenotype of non-syndromic tooth agenesis caused by PAX9 variants,which can provide a basis for the genetic diagnosis of tooth agenesis.Methods We collected the data of 44 patients with non-syn-dromic oligodontia who underwent treatment at Stomatological Hospital of Hebei Medical University between 2018 and 2023.Whole-exome sequencing was performed on the peripheral blood of the proband and its core family members,and the variants were verified by Sanger sequencing.Pathogenicity analysis and function prediction of the variants were per-formed using bioinformatics tools.The correlation between the genotype of PAX9 variant and its corresponding pheno-type was examined by reviewing 55 publications retrieved from PubMed.The studies involved 232 tooth agenesis pa-tients with PAX9 variants.Results A novel PAX9 c.447delG(p.Pro150Argfs*62)and a reported PAX9 c.406C>T(p.Gln136*)were identified in two Chinese families.Through bioinformatics analysis and three-dimensional structural mod-eling,we postulated that the frameshift variant was pathogenic.The outcome was the premature cessation of PAX9 pro-tein,which caused severe structural and functional deficiencies.Summarizing the PAX9 genotype-phenotype relationship revealed that patients carrying the PAX9 variant commonly led to loss of the second molars.Conclusion We identified the novel PAX9 c.447delG(p.Pro150Argfs*62)in a Chinese family of non-syndromic oligodontia,expanding the known variant spectrum of PAX9.The most susceptible tooth position for PAX9 variants of tooth agenesis was the second mo-lars and the deciduous molars during the deciduous dentition.