ObjectiveTo decipher the mechanism by which Zuoguiwan （ZGW） treat hyperthyroidism in rats with kidney-Yin deficiency based on the dopamine receptor D4 （DRD4）/nicotinamide adenine dinucleotide phosphate （NADPH） oxidase 4 （NOX4） signaling pathway. MethodsThe rat model of kidney-Yin deficiency was induced by unilateral intramuscular injection of dexamethasone （0.35 mg·kg^-1）. After successful modeling， the rats were randomized into model， methimazole （positive control， 5 mg·kg^-1）， low-， medium-， and high-dose （1.85， 3.70， 7.40 g·kg^-1， respectively） ZGW， and normal control groups. After 21 days of continuous gavage， the behavioral indexes and body weight changes of rats were evaluated. The pathological changes of the renal tissue were observed by hematoxylin-eosin staining. The serum levels of thyroid hormones ［triiodothyronine （T₃）， thyroxine （T₄）， thyroid-stimulating hormone （TSH）］， renal function indexes ［serum creatine （Scr） and blood urea nitrogen （BUN）］， energy metabolism markers ［cyclic adenosine monophosphate （cAMP） and cyclic guanosine monophosphate （cGMP）］， and oxidative stress-related factors ［superoxide dismutase （SOD）， malondialdehyde （MDA）， and NADPH）］ were measured by enzyme-linked immunosorbent assay （ELISA）. Western blot was employed to analyze the expression of DRD4， NOX4， mitochondrial respiratory chain complex proteins ［NADH：ubiquinone oxidoreductase subunit S4 （NDUFS4） and cytochrome C oxidase subunit 4 （COX4）］， and inflammation-related protein ［tumor necrosis factor-alpha （TNF-α）， interleukin-6 （IL-6）， p38 mitogen-activated protein kinase （MAPK）］ pathway in the renal tissue. ResultsCompared with the normal group， the model group showed mental malaise， body weight decreases （P<0.01）， inflammatory cell infiltration in the renal tissue， a few residual parotid glands in the thyroid， elevations in serum levels of T₃， T₄， Scr， BUN， cAMP， cAMP/cGMP， MDA， and NADPH （P<0.01）， down-regulation in protein levels of TSH， SOD， and DRD4 （P<0.05， P<0.01）， and up-regulation in expression of NOX4， p-p38 MAPK/p38 MAPK， and inflammatory factors （P<0.01）. Compared with the model group， ZGW increased the body weight （P<0.05， P<0.01）， reduced the infiltration of renal interstitial inflammatory cells， restored the thyroid structure and follicle size， lowered the serum levels of T₃， T₄， Scr， BUN， cAMP， cAMP/cGMP， MDA and NADPH （P<0.05， P<0.01）， up-regulated the expression of TSH， SOD and DRD4 （P<0.05， P<0.01）， and down-regulated the expression of NOX4， p-p38 MAPK/p38 MAPK， and inflammatory factors （P<0.05， P<0.01）. Moreover， high-dose ZGW outperformed methimazole （P<0.05）. ConclusionBy activating DRD4， ZGW can inhibit the expression of NOX4 mediated by the p38 MAPK pathway， reduce oxidative stress and inflammatory response， thereby ameliorating the pathological state of hyperthyroidism due to kidney-Yin deficiency. This study provides new molecular mechanism support for the clinical application of ZGW.

ObjectiveBased on whole-animal mass spectrometry imaging technology， spatial metabolomics was used to characterize in situ the metabolic alteration patterns in the lungs and brain of a rat model of lung heat-induced cough and asthma， as well as after treatment with Xiebai San. MethodsNine Sprague-Dawley （SD） rats were randomly divided into a blank group （physiological saline）， a model group （physiological saline）， and a Xiebai San group （9 g·kg^-1）， with three rats in each group. The model group and the Xiebai San group were both induced using lipopolysaccharide-ovalbumin （LPS-OVA） to establish an asthma rat model. After treatment with Xiebai San， the animals were euthanized on day 21 and rapidly frozen in liquid nitrogen to preserve morphology. Whole-animal tissue sections were prepared using a cryomicrotome， and imaging was performed using the Air-flow-assisted Desorption Electrospray Ionization Mass Spectrometry Imaging （AFADESI-MSI） platform. Based on the corresponding optical images， ion data of metabolites from the lung and brain tissues of each group were extracted. Differential metabolites were analyzed using SIMCA and GraphPad Prism 9.0 software. Metabolites were identified using the HMDB （https：//hmdb.ca/） and LipidMAPS^® （https：//www.lipidmaps.org/） databases， and metabolic changes in the lungs and brain were analyzed. ResultsMass spectrometry imaging showed that， after Xiebai San intervention， components such as neoglycyrrhizin and glycyrrhizin from Glycyrrhizae Radix et Rhizoma， as well as palmitamide from Lycii Cortex， were significantly distributed in the lung and brain tissues of rats. Lung analysis indicated that substances with anti-inflammatory effects， such as citric acid， were significantly decreased （P0.01）， while lipid metabolites such as lysophosphatidylethanolamine （LPE 17：1）， LPE （22：4）， and LPE （19：0） （P0.01） were significantly increased， showing a marked inflammatory response in the model group. After Xiebai San intervention， these conditions were notably improved. Analysis of metabolic changes in brain tissue showed that， compared with the blank group， amino acid and fatty acid metabolic pathways in the model group exhibited restricted alterations. Among them， levels of aspartic acid， glutamic acid， fatty acid （FA 18：5）， hydroxy fatty acids （FAHFA 36：0；O）， FA （6：1；O6）， and LPE （18：1） increased， whereas FA （16：0） and FA （20：4） significantly decreased. Administration of Xiebai San improved these metabolic abnormalities in the brain. Systematic analysis of lung and brain metabolic changes in rats with lung heat-induced cough and asthma showed that antioxidant unsaturated phospholipid substances were significantly decreased in the model group， suggesting oxidative stress and inflammation-related lung-brain axis responses after the onset of lung heat-induced cough and asthma. ConclusionUsing whole-animal mass spectrometry imaging combined with spatial metabolomics revealed the in vivo distribution of Xiebai San constituents， characterized the metabolic alterations in the lungs and brain caused by lung heat-induced cough and asthma， and systematically demonstrated the lung-brain axis inflammatory responses and the regulatory effects of Xiebai San. These findings provide valuable information for the study of Chinese medicine in lung heat-induced cough and asthma.

ObjectiveBased on whole-animal mass spectrometry imaging technology， spatial metabolomics was used to characterize in situ the metabolic alteration patterns in the lungs and brain of a rat model of lung heat-induced cough and asthma， as well as after treatment with Xiebai San. MethodsNine Sprague-Dawley （SD） rats were randomly divided into a blank group （physiological saline）， a model group （physiological saline）， and a Xiebai San group （9 g·kg^-1）， with three rats in each group. The model group and the Xiebai San group were both induced using lipopolysaccharide-ovalbumin （LPS-OVA） to establish an asthma rat model. After treatment with Xiebai San， the animals were euthanized on day 21 and rapidly frozen in liquid nitrogen to preserve morphology. Whole-animal tissue sections were prepared using a cryomicrotome， and imaging was performed using the Air-flow-assisted Desorption Electrospray Ionization Mass Spectrometry Imaging （AFADESI-MSI） platform. Based on the corresponding optical images， ion data of metabolites from the lung and brain tissues of each group were extracted. Differential metabolites were analyzed using SIMCA and GraphPad Prism 9.0 software. Metabolites were identified using the HMDB （https：//hmdb.ca/） and LipidMAPS^® （https：//www.lipidmaps.org/） databases， and metabolic changes in the lungs and brain were analyzed. ResultsMass spectrometry imaging showed that， after Xiebai San intervention， components such as neoglycyrrhizin and glycyrrhizin from Glycyrrhizae Radix et Rhizoma， as well as palmitamide from Lycii Cortex， were significantly distributed in the lung and brain tissues of rats. Lung analysis indicated that substances with anti-inflammatory effects， such as citric acid， were significantly decreased （P0.01）， while lipid metabolites such as lysophosphatidylethanolamine （LPE 17：1）， LPE （22：4）， and LPE （19：0） （P0.01） were significantly increased， showing a marked inflammatory response in the model group. After Xiebai San intervention， these conditions were notably improved. Analysis of metabolic changes in brain tissue showed that， compared with the blank group， amino acid and fatty acid metabolic pathways in the model group exhibited restricted alterations. Among them， levels of aspartic acid， glutamic acid， fatty acid （FA 18：5）， hydroxy fatty acids （FAHFA 36：0；O）， FA （6：1；O6）， and LPE （18：1） increased， whereas FA （16：0） and FA （20：4） significantly decreased. Administration of Xiebai San improved these metabolic abnormalities in the brain. Systematic analysis of lung and brain metabolic changes in rats with lung heat-induced cough and asthma showed that antioxidant unsaturated phospholipid substances were significantly decreased in the model group， suggesting oxidative stress and inflammation-related lung-brain axis responses after the onset of lung heat-induced cough and asthma. ConclusionUsing whole-animal mass spectrometry imaging combined with spatial metabolomics revealed the in vivo distribution of Xiebai San constituents， characterized the metabolic alterations in the lungs and brain caused by lung heat-induced cough and asthma， and systematically demonstrated the lung-brain axis inflammatory responses and the regulatory effects of Xiebai San. These findings provide valuable information for the study of Chinese medicine in lung heat-induced cough and asthma.

Adverse drug reactions （ADRs） refer to harmful or unintended reactions unrelated to the intended purpose of medication administration， which can lead to various issues such as accelerated disease progression and prolonged hospitalization. Traditional ADRs monitoring systems （such as spontaneous reporting systems） suffer from limitations such as low reporting rates and inconsistent data quality， which hinder the early prevention and control of ADRs. With the rapid development of information technology， machine learning has emerged as a powerful tool for management and decision-making of ADRs by leveraging its strengths in feature extraction and dynamic temporal pattern analysis. By reviewing relevant literature at home and abroad in recent years， this paper summarizes the progress in the application of machine learning for ADRs prediction. It is found that machine learning has gradually been applied to the early warning and risk prediction of ADRs in target organs such as the kidneys， liver， heart and bone marrow （such as acute kidney injury， drug-induced liver injury， and so on）. Although machine learning demonstrates significant application potential in the field of ADRs prediction， it still faces limitations such as inadequate quality control of clinical data， lack of standardized criteria for model performance evaluation， insufficient model interpretability and difficulties in clinical translation. In the future， the development trend of machine learning in the field of ADRs prediction should follow a “technology-validation-integration” pathway to systematically promote the practical implementation of models.

Objective: To quantitatively assess the health risk of preservatives from beverages around primary schools in Anshun City, and to provide scientific basis for precise food safety supervision. Methods: From December 2023 to July 2024, 602 beverage samples were randomly collected from within 100 meters of 19 primary schools in Anshun City. The content of benzoic acid, sorbic acid, and dehydroacetic acid was detected according to GB 5009 series standards. Combined with children s physiological parameters (body weight 30 kg, daily intake 0.15 L), the Hazard Quotient (HQ) and Hazard Index (HI) models were used to evaluate health risks. Results: The total detection rate of preservatives from beverages around primary schools was 63.0%, and the total over limit rate was 9.0%. The detection rate of preservatives in flavored beverages was the highest (72.6%), and the highest over limit rate of preservatives in special purpose beverages was the highest (17.2%). The single preservative HQ (benzoic acid up to 0.47 ) and mixed HI (up to 0.55) of all samples were below 1(safety threshold). However, the HQ value of benzoic acid in flavored beverages (0.47) was 2.9 times that of sorbic acid (0.16), contributing significantly to health risk. Sensitivity analysis showed that if the daily consumption increased to 0.3 L, the HI value of flavored beverages would rise to 1.11, exceeding the safety threshold. Enterprise scale analysis showed that the exceedance rate of special purpose beverages in large enterprises reached 30.0%, while micro enterprises, accounting for a dominant market share (52.2%), constituted the main source of children s daily exposure to their products. Conclusions The overall health risk of perservatives in beverages sold near primary schools in Anshun City is controllable, but there is a noticeable risk of gradient. The risk of children’s exposure to preservatives through beverage consumption should not be ignored.

ObjectiveTo establish a mouse model of rheumatoid arthritis with interstitial lung disease （RA-ILD） in DBA/1 mice using Porphyromonas gingivalis （Pg） infection combined with collagen-induced arthritis （CIA）， and to comprehensively evaluate pathological characteristics in joints， lungs， and serum. MethodsForty DBA/1 mice were randomly divided into four groups， i.e.， Control， Pg infection （Pg）， CIA， and Pg infection combined with CIA （Pg+CIA）， with 10 mice in each group. Arthritis clinical symptoms were evaluated by recording arthritis incidence and clinical scores. Micro-CT scanning was used to assess knee joint pathology. Histopathological changes and collagen deposition in knee joints and lung tissues were analyzed using hematoxylin-eosin （HE） and Masson staining. Immunohistochemistry was performed to detect protein expression of α-smooth muscle actin （α-SMA）， typeⅠ collagen （ColⅠ）， and fibronectin （FN） in lung tissues. Real-time quantitative polymerase chain reaction（Real-time PCR）was used to measure mRNA expression levels of α-SMA， ColⅠ， FN， tumor necrosis factor-α （TNF-α）， interleukin-6 （IL-6）， and IL-1β in lung tissues. Enzyme-linked immunosorbent assay （ELISA） was used to detect serum levels of Pg， cyclic citrullinated peptide （CCP）， and immunoglobulin G （IgG）. ResultsJoint lesions： The CIA and Pg+CIA groups showed 100% arthritis incidence， with evident joint redness， swelling， and deformity. The number of affected limbs was 27 and 28， and clinical scores were 68 and 70， respectively. No obvious clinical symptoms were observed in the Pg group. Histopathological and imaging analyses showed severe joint lesions in the CIA and Pg+CIA groups， with significantly increased histopathological scores， bone mineral density， bone volume fraction， trabecular thickness， and trabecular number compared to the Control group （P<0.01）. No obvious joint pathology was observed in the Pg group. Lung lesions： The Pg+CIA group exhibited marked alveolar inflammation， interstitial inflammatory cell infiltration， and alveolar wall thickening， with pronounced blue staining of collagen fibers. Histopathological scores and collagen area ratios were significantly higher than those of the Control， Pg， and CIA groups （P<0.05）. Lung protein and mRNA expression levels of α-SMA， ColⅠ， and FN were markedly increased， and mRNA levels of IL-6， TNF-α， and IL-1β were significantly elevated compared to the Control group （P<0.05）. Serology： The Pg+CIA group showed significantly higher levels of CCP， Pg， and IgG compared with the Control， Pg， and CIA groups （P<0.05）. ConclusionDBA/1 mice subjected to Pg infection combined with CIA exhibited pronounced symptoms and pathological features of RA-ILD， along with elevated serum anti-CCP antibody levels. This model represents a novel RA-ILD mouse model， providing a valuable experimental tool for investigating RA-ILD pathogenesis and developing new therapeutics， and serves as a basis for establishing anti-cyclic citrullinated peptide antibody （ACPA）-positive RA-ILD animal models.

ObjectiveTo investigate the therapeutic effect of Astragali Radix-mediated changes in gut microbiota on treating type 2 diabetes （T2DM）. MethodsA 12-week randomized， placebo-controlled clinical trial enrolled eighty patients with newly diagnosed type 2 diabetes and poor glycemic control in the Qi deficiency type. All patients received insulin therapy. The observation group （40 cases） was administered with Astragali Radix Granules， while the control group （40 cases） received a placebo. Both treamtents were taken orally twice daily. Changes in gut microbiota were assessed by 16s rDNA sequencing. Serum glucagon-like peptide-1 （GLP-1） levels were measured using enzyme-linked immunosorbent assay （ELISA）. Glucose metabolism indicators including fasting blood glucose （FPG）， 2-hour postprandial blood glucose （2 h PG），glycated albumin（GA）， and glycated hemoglobin （HbA1c） were evaluated. Pancreatic function was evaluated using fasting C-peptide （FCP）， 2-hour postprandial C-peptide （2 h CP）， and C-peptide area under the curve （AUC_cp）. Traditional Chinese medicine （TCM） syndrome scores， clinical efficacy， and safety indicators were also observed. ResultsIn terms of glucose metabolism indicators， compared with the baseline， both groups exhibited significantly lower FPG， 2 h PG， GA and HbA1C （P<0.01），while FCP， 2 h CP and AUC_cp were significantly higher （P<0.01）. Compared with the control group after the treatment， the observation group showed significantly lower FPG， 2 h PG， GA and HbA1C（P<0.05， P<0.01），and significantly higher FCP， 2 h CP and AUC_cp （P<0.05， P<0.01）， indicating that Astragali Radix can improve glucose metabolism. In terms of the diversity of gut microbiota， no significant differences were detected in the Chao1， Shannon and Simpson indexes of the two groups compared with their respective baselines. However， compared with the post-treatment control group， the observation group demonstrated significant increases in the Chao1， Shannon and Simpson indexes （P<0.05， P<0.01）. The β-diversity analysis showed significant separation in gut microbiota composition before and after treatment in both groups， indicating that Astragali Radix can significantly alter the structure and improve the diversity of gut microbiota. At the phylum level， compared with the baseline， both groups showed a significant increase in the relative abundance of Bacteroidota（P<0.01）. The relative abundance of the potentially harmful phylum Proteobacteria was significantly lower in the observation Group after treatment （P<0.01）. Compared with the post-treatment control group， the observation group had a significantly higher relative abundance of Bacteroidota（P<0.01）. No significant difference was found in Firmicutes/Bacteroidota （F/B） ratio between the two groups after treatment， and other phyla showed no significant differences. At the genus level， compared with the baseline， the observation group exhibited a significant increase in Bacteroides （P<0.01） and a significant decrease in Escherichia-Shigella （P<0.01）， whereas no significant difference was seen in the control group . Compared with the control group after treatment， the observation group after treatment had a significantly higher relative abundance of Bacteroides （P<0.01）. No significant differences were seen in other genera. Linear discriminant analysis （LDA） identified potential characteristics taxa： in the observation group， Bacteroidota at the phylum level and Bacteroides and Dubosiella at the genus level， in the control group， Proteobacteria at the phylum level as well as Barnesiella and Staphylococcus at the genus level. Correlation analysis based on a heatmap revealed that GLP-1 levels were positively correlated with Firmicutes， F/B ratio and Fusobacterium， and negatively correlated with Bacteroidota， Proteobacteria， Bacteroides and Escherichia-Shigella. In terms of clinical efficacy， compared with the control group， the total effective rate of the observation group was significantly higher （P<0.05）. Compared with the baseline， the scores for shortness of breath， fatigue， weakness， spontaneous sweating and reluctance to speak significantly decreased in both groups （P<0.01）. Compared with the control group after treatment， the score for weakness was significantly lower in the observation group （P<0.01），indicating that Astragali Radix could improve clinical symptoms and alleviate weakness symptoms. In terms of safety， compared with the baseline， alanine aminotransferase （ALT） levels significantly decreased in both groups （P<0.05，P<0.01），indicating that Astragali Radix did not induce any significant abnormalities in liver and kidney functions. ConclusionAstragali Radix demonstrates the potential to significantly improve the gut microbiota environment in patients of newly diagnosed type 2 diabetes with Qi deficiency. The therapeutic effect may contribute to glycemic control， possibly mediated by an elevation in GLP-1 level. These findings may support its further clinical investigations and potential applications.

This article systematically analyzed the historical evolution of the origin， scientific name， producing area， quality evaluation， harvesting and processing， and other aspects of Quisqualis Fructus by consulting the ancient materia medica， medical books， prescription books， local literature and combining with the modern literature and standards， summarized and explored the development rules of its medicinal properties and efficacy along with their underlying causes， in order to provide support for the development and utilization of famous classical formulas containing this herb. According to the textual research， Shijunzi was first recorded as Liuqiuzi in Nanfang Caomuzhuang of the Jin dynasty， and the name of Shijunzi was first used in Kaibao Bencao of the Song dynasty， which has been consistently used throughout subsequent dynasties， and there were also aliases such as Junziren， Sijunzi， and Dujilizi. The mainstream source of Quisqualis Fructus used in the past dynasties has been the dried mature fruits of Quisqualis indica， a plant belonging to the family Combretaceae. In modern times， its variety Q. indica var. villosa has also been recorded as the medicinal material of Quisqualis Fructus. In 2007， the Flora of China（English edition） designated Q. indica var. villosa as a synonym of Q. indica. Today， the accepted name of Shijunzi is updated to Combretum indicum. According to ancient herbal records， the producing areas of Quisqualis Fructus were Guangdong， Hong Kong， Macao， Guangxi， Hainan， Sichuan and Fujian， and then gradually expanded to Yunnan， Taiwan， Jiangxi and Guizhou. Since the Song dynasty， two major production regions have gradually emerged in Sichuan， Chongqing and Fujian. Currently， it is primarily cultivated in Chongqing， Guangxi and other areas， with Chongqing yielding the highest output. Since modern times， superior quality has been defined by large size， a purple-black surface， plump grains， and a yellowish-white kernel. According to ancient herbal records， the harvesting period of Quisqualis Fructus was the July and August of the lunar calendar， mostly used raw after shelling or with the shell intact， it underwent processing methods such as cleaning， slicing， mixing， steaming， roasting， stewing， and frying. Currently， the harvesting period is autumn， followed by sun-drying or low-heat drying， with processing methods including cleaning， stir-frying， and stewing. In ancient and modern literature， the records of the properties， functions and indications of Quisqualis Fructus are basically the same， that is， sweet in taste， warm in nature， predominantly non-toxic， belonging to the spleen and stomach meridians. It possesses effects of insecticide， decontamination and invigorating spleen for ascariasis， enterobiasis， abdominal pain due to worm accumulation and infantile malnutrition.The contraindications for use primarily include avoiding consumption by individuals without parasitic infestations， limiting use for those with spleen-stomach deficiency-cold， refraining from drinking hot tea during medication， and avoiding excessive intake. Based on the textual research， it is suggested that the dried mature fruits of Q. indica should be used as the medicinal material for the development of famous classical formulas containing Quisqualis Fructus. Processing methods may be chosen according to prescription requirements， and the raw products is recommended for medicinal use if not specified.

BACKGROUND:In the initial stage of growth plate injury inflammation,platelet-derived growth factor BB promotes the repair of growth plate injury by promoting mesenchymal progenitor cell infiltration,chondrogenesis,osteogenic response,and regulating bone remodeling. OBJECTIVE:To elucidate the action mechanism of platelet-derived growth factor BB after growth plate injury. METHODS:PubMed,VIP,WanFang,and CNKI databases were used as the literature sources.The search terms were"growth plate injury,bone bridge,platelet-derived growth factor BB,repair"in English and Chinese.Finally,66 articles were screened for this review. RESULTS AND CONCLUSION:Growth plate injury experienced early inflammation,vascular reconstruction,fibroossification,structural remodeling and other pathological processes,accompanied by the crosstalk of chondrocytes,vascular endothelial cells,stem cells,osteoblasts,osteoclasts and other cells.Platelet-derived growth factor BB,as an important factor in the early inflammatory response of injury,regulates the injury repair process by mediating a variety of cellular inflammatory responses.Targeting the inflammatory stimulation mediated by platelet-derived growth factor BB may delay the bone bridge formation process by improving the functional activities of osteoclasts,osteoblasts,and chondrocytes,so as to achieve the injury repair of growth plate.Platelet-derived growth factor BB plays an important role in angiogenesis and bone repair tissue formation at the injured site of growth plate and intrachondral bone lengthening function of uninjured growth plate.Inhibition of the coupling effect between angiogenesis initiated by platelet-derived growth factor BB and intrachondral bone formation may achieve the repair of growth plate injury.

BACKGROUND:Post and core restoration is a common choice for tooth defects,but the repair effects of various post and core materials are different. OBJECTIVE:To evaluate the stress distribution at the post and core,tooth root,and bonding agent site of post and core models made of different elastic modulus post and core materials using finite element method. METHODS:A three-dimensional root canal treated maxillary central incisor model was built using three-dimensional modeling software,which was restored with a full ceramic crown.The post and core materials in the restoration used nanoceramic resin(elastic modulus=12.8 GPa),composite resin(elastic modulus=16 GPa),hybrid ceramic(elastic modulus=34.7 GPa),glass ceramic(elastic modulus=95 GPa),titanium alloy(elastic modulus=112 GPa),and zirconia(elastic modulus=209.3 GPa).The model was fixed in cortical bone.A 100 N concentrated force of 45° from the long axis of the tooth was applied to 1/3 of the crown and tongue side of the central incisor.The stress distribution of the post and core,dentin,and tooth-root bonding agent in the model was repaired by the maximum principal stress criterion. RESULTS AND CONCLUSION:(1)When the post and core materials with higher elastic modulus was used,the post-core stress in the repair model was more concentrated.When the elastic modulus of the post and core materials(nanoceramic resin and composite resin)was close to dentin,the stress distribution of the post and core was more uniform.The stress distribution of dentin in all restoration models was similar regardless of post and core materials.When the post and core with higher elastic modulus was used,more stress concentration was shown at the post and root bonding agent in the repair model.(2)The maximum stress values at the post and core,tooth root,and the bonding agent site of post and tooth root in the nanoceramic resin model were 31.00,33.21,and 0.51 MPa,respectively.The maximum stress values at the post and core,tooth root,and the bonding agent between the post and tooth root in the composite resin model were 36.84,33.14,and 0.59 MPa,respectively.In the mixed ceramic model,the maximum stress values at the post and core,tooth root,and the bonding agent between the post and tooth root were 64.05,32.83,and 1.00 MPa,respectively.In the glass ceramic model,the maximum stress values at the post and core,tooth root,and the bonding agent between the post and tooth root were 112.30,32.69,and 1.73 MPa,respectively.In the titanium alloy model,the maximum stress values of the post and core,tooth root,and the bonding agent between the post and tooth root were 120.00,32.17,and 1.86 MPa,respectively.In the zirconia model,the maximum stress values of the post and core,tooth root,and the bonding agent between the post and tooth root were 148.80,31.85,and 2.28 MPa,respectively.(3)The higher the elastic modulus of the post and core material,the higher the maximum stress at the post and core during restoration.The elastic modulus of the post and core material had no significant effect on the maximum stress of the dental bonding agent and dentin.