1.Comorbidity of myopia, and overweight and obesity among primary and middle school students in Yanqing District
WANG Yun ; SHEN Yunkui ; LIU Bohao ; CHEN Jing ; ZHANG Kun
Journal of Preventive Medicine 2026;38(1):85-88
Objective:
To investigate the prevalence of comorbidity of myopia, and overweight and obesity among primary and middle school students in Yanqing District, Beijing Municipality, so as to provide the evidence for \prevention and control of comorbidity.
Methods:
In September from 2020 to 2024, a stratified cluster sampling method was adopted annually to select primary, junior high school, senior high school, and vocational high school students in Yanqing District as survey subjects. Myopia was screened based on Screening Protocol for Myopia in Children and Adolescents. Height an weight were measured, and overweight and obesity were determined using the Screening for overweight and Obesity in School-Age Children and Adolescents.
Results:
A total of 9 883 individuals were surveyed, including 5 219 primary school students (52.81%), 2 486 junior high school students (25.15%), and 2 178 senior high school / vocational high school students (22.04%). There were 5 154 boys (52.15%) and 4 729 girls (47.85%). From 2020 to 2024, the numbers of primary and middle school students in Yanqing District with myopia, overweight, and obesity were 4 426, 1 897, and 3 164, respectively, with detection rates of 44.78%, 19.19%, and 32.01%. The detection rates of myopia, overweight, and obesity showed an increasing trend with the elevation of school stage (all P<0.05). The detection rate of myopia was higher in girls than in boys, while the detection rate of obesity was lower in girls than in boys (all P<0.05). There were 2 588 individuals with both myopia and overweight/obesity, representing a detection rate of 26.19%, which showed an increasing trend (P<0.05), rising from 25.04% in 2020 to 34.41% in 2024. The detection rates of comorbidity of myopia, and overweight and obesity among primary school, junior high school, and senior high school / vocational high school students were 13.22%, 36.93%, and 45.00%, respectively, showing an increasing trend with the elevation of school stage (P<0.05). The difference between genders was not statistically significant (P>0.05).
Conclusions
The detection rates of comorbidity of myopia, and overweight and obesity among primary and middle school students in Yanqing District is relatively high and shows an upward trend, with students in higher school stage being the key target group for prevention and control. It is recommended to strengthen health education on the co-prevention of multiple health issues and implement differentiated interventions based on school stages.
2.Clinical observation of doxycycline in the treatment of macrolide-unresponsive Mycoplasma pneumoniae pneumonia in children under 8 years of age
Shanshan LI ; Jishan ZHENG ; Yanyan CHEN ; Longhui SHEN
China Pharmacy 2025;36(4):464-468
OBJECTIVE To investigate the efficacy and safety of doxycycline in the treatment of macrolide-unresponsive Mycoplasma pneumoniae pneumonia (MUMPP) in children under 8 years of age. METHODS The medical records of children with MUMPP admitted to the Women and Children’s Hospital Affiliated to Ningbo University were collected from January 1st, 2023 to December 31st, 2023. They were divided into doxycycline group (44 cases), doxycycline combined with methylprednisolone group (35 cases), and azithromycin combined with methylprednisolone group (35 cases) according to the treatment methods. Doxycycline group was given Doxycycline hyclate enteric-coated capsules; doxycycline combined with methylprednisolone group was given Doxycycline hyclate enteric-coated capsules and Methylprednisolone sodium succinate for injection; azithromycin combined with methylprednisolone group was given Azithromycin for injection and Methylprednisolone sodium succinate for injection. Treatment courses of 3 groups lasted for 10 d. The fever reduction rate, the time of fever reduction and improvement rate of lung infection absorption were compared among the three groups. The occurrence of adverse drug reactions was recorded during their hospitalization and followed up within 5 months after discharge. RESULTS The fever reduction rats 48, 72 h after treatment and improvement rate of lung infection absorption in doxycycline group and doxycycline combined with methylprednisolone group were significantly higher than azithromycin combined with methylprednisolone group; the time of fever reduction was significantly shorter than azithromycin combined with methylprednisolone group (P<0.05); there was no statistical significance in the difference between the doxycycline group and the doxycycline combined with methylprednisolone group (P>0.05). There was no statistical significance in the incidence of rash, vomiting, abdominal pain, diarrhea, and elevated transaminases among the three groups during hospitalization and within 5 months after discharge (P>0.05). None of the children treated with doxycycline suffered from tooth discoloration or enamel hypoplasia. CONCLUSIONS Doxycycline has good efficacy and safety in therapy of MUMPP in children under 8 years of age; adjunctive coadministration of low-dose glucocorticoids does not necessarily result in significant additional efficacy.
3.The Effect of Zhiqiao Gancao Decoction (枳壳甘草汤) on Intervertebral Disc Nucleus Pulposus Cell Apoptosis and the Hippo-YAP/TAZ Signaling Pathway in Tail Intervertebral Disc Degeneration Model Rats
Zaishi ZHU ; Zeling HUANG ; Junming CHEN ; Bo XU ; Binjie LU ; Hua CHEN ; Xingxing DUAN ; Yuwei LI ; Xiaofeng SHEN
Journal of Traditional Chinese Medicine 2025;66(5):509-517
ObjectiveTo investigate the possible mechanism by which Zhiqiao Gancao Decoction (枳壳甘草汤, ZGD) delays intervertebral disc degeneration (IDD) based on the Hippo-yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ) signaling pathway. MethodsA total of 50 SD rats were randomly divided into sham surgery group, model group, low-dose ZGD group, high-dose ZGD group, and high-dose ZGD + inhibitor group, with 10 rats in each group. In the sham surgery group, the rats were pierced in the skin and muscle at the Co6/7/8 segments of the tail with a 21G needle (depth approximately 2 mm) without damaging the intervertebral disc. In the other groups, rats were injected with a 21G needle at the Co6/7/8 segments of the tail to establish an IDD model by piercing the tail intervertebral disc 5 mm. One week after modeling, rats in the low-dose and high-dose ZGD groups were given 6.24 and 12.24 g/(kg·d) of the decoction via gastric gavage, respectively. The high-dose ZGD + inhibitor group was given 12.24 g/(kg·d) of the decoction and an intraperitoneal injection of YAP/TAZ inhibitor Verteporfin 10 mg/kg. The sham surgery and model groups were given 5 ml/(kg·d) of normal saline via gavage. The gavage was given once a day, and the intraperitoneal injection was given every other day. After 4 weeks of continuous intervention, the pathological changes of the tail intervertebral discs were observed using HE staining, Oil Red O-Green staining, and Toluidine Blue staining. Immunohistochemistry was used to detect the expression of aggrecan and MMP3 in the nucleus pulposus. TUNEL fluorescence staining was performed to detect apoptosis in the nucleus pulposus, and the apoptosis rate was calculated. Western blot was used to detect the Hippo-YAP/TAZ signaling pathway, including YAP, phosphorylated YAP (p-YAP), phosphorylated MST1/2 (p-MST1/2), phosphorylated TAZ (p-TAZ) and apoptosis-related proteins, such as Cleaved Caspase 3, P53, Bcl-2 and Bax. ResultsCompared with sham surgery group, the rats in the model group showed significant degenerative changes in the intervertebral disc. The levels of aggrecan, Bcl-2, and YAP proteins in the nucleus pulposus decreased, while the levels of p-MST1/2, p-YAP, p-TAZ, P53, Bax, Cleaved Caspase 3, MMP3 proteins, and the apoptosis rate increased (P < 0.01). Compared with the model group, the drug intervention groups showed partial recovery in intervertebral disc degeneration. The levels of aggrecan, Bcl-2, and YAP proteins increased, while the levels of p-MST1/2, p-YAP, p-TAZ, P53, Bax, Cleaved Caspase 3, MMP3 proteins, and the apoptosis rate decreased (P<0.05 or P<0.01). The high-dose ZGD group showed more significant recovery in intervertebral disc degeneration compared to the low-dose ZGD group, with a decrease in the levels of p-MST1/2, p-YAP, p-TAZ, P53, Bax, Cleaved Caspase 3, MMP3 proteins, and apoptosis rate, and an increase in the levels of aggrecan, Bcl-2, and YAP proteins (P<0.05 or P<0.01). Compared with the high-dose ZGD group, the high-dose ZGD + inhibitor group showed a reduced recovery in intervertebral disc degeneration, with an increase in the levels of p-MST1/2, p-YAP, p-TAZ, P53, Bax, Cleaved Caspase 3, MMP3 proteins, and apoptosis rate, and a decrease in the levels of aggrecan, Bcl-2, and YAP proteins (P<0.05 or P<0.01). ConclusionZGD may delay intervertebral disc degeneration by inhibiting the phosphorylation of YAP in the nucleus pulposus, maintaining the function of the Hippo-YAP/TAZ signaling pathway, and reducing apoptosis of nucleus pulposus cells.
4.Cyclocarya paliurus Polysaccharide Inhibits Benign Prostatic Hyperplasia by Reducing 5α-Reductase 2
Qinhui DAI ; Mengxia YAN ; Chen WANG ; Chenjun SHEN ; Chenying JIANG ; Bo YANG ; Huajun ZHAO ; Zhihui ZHU
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(3):107-114
ObjectiveTo investigate the effect and mechanism of polysaccharide in water extract of Cyclocarya paliurus (CPWP) in inhibiting benign prostatic hyperplasia (BPH). MethodsCPWP was obtained by heating reflux, aqueous extraction, alcohol precipitation, and freeze drying. The chemical composition and structural properties of CPWP were analyzed by high performance liquid chromatography with 1-pheny-3-methyl-5-pyrazolone pre-column derivatization and infrared spectroscopy. Male SD rats were randomly assigned into control, model, finasteride (ig 5 mg·kg-1), and low-, medium-, and high-dose (ig 50, 75, 100 mg·kg-1) CPWP groups, with 8 rats in each group. The BPH model was established by subcutaneously injecting propionate testosterone in castrated rats. The rats in the drug intervention groups were administrated with corresponding drugs, and those in the control group were administrated with an equal volume of normal saline each day. After 30 consecutive days, the rats were sacrificed, and the prostate tissue was separated and weighed. The effects of drug interventions on the body weight, prostate wet weight, and prostate index of rats were examined. The prostate tissue was stained with hematoxylin-eosin (HE) for observation of pathological changes. Enzyme-linked immunosorbent assay was employed to measure the level of dihydrotestosterone (DHT), and immunohistochemical staining was used to detect the expression of steroid 5 alpha-reductase 2 (SRD5A2) and Ki67 in the prostate tissue. ResultsCPWP was identified as a saccharide, with characteristic absorption peaks of saccharides. CPWP showed the total sugar content of 44.15% and molecular weight within the range of 5.5-78.8 kDa, being composed of mannose, rhamnose, galacturonic acid, glucose, galactose, xylose, and arabinose. Compared with the control group, the model group had significantly increased prostate wet weight and prostate index (P<0.01), thick and tall prostate epithelial cells, increased internal wrinkles, papillary expansion into the cavity, an elevation in DHT level in the serum, and up-regulated expression of SRD5A2 and Ki67 in the prostate tissue (P<0.05, P<0.01). Compared with the model group, both the finasteride and CPWP groups showed decreases in prostate wet weight and prostate index (P<0.05, P<0.01), thinned prostate epithelial cells, with only a small portion of internal wrinkles and papillary expansion into the cavity, shortened papillary protrusions, lowered DHT level in the serum, and down-regulated expression of SRD5A2 and Ki67 in the prostate tissue (P<0.01). Moreover, CPWP exerted effects in a dose-dependent manner. ConclusionCPWP inhibits BPH by regulating the expression of SRD5A2.
5.The Effect of Modified Ditan Decoction (涤痰汤) on Cognitive Function and Resting-State Functional Magnetic Resonance Imaging of the Brain in Chronic Intermittent Hypoxia Model Rats
Naijie CHEN ; Xiaoting WANG ; Fengsheng XU ; Shuanghong SHEN ; Zuanfang LI ; Qin CHEN ; Jin CHEN ; Runhua WU
Journal of Traditional Chinese Medicine 2025;66(1):71-78
ObjectiveTo explore the effect of modified Ditan Decoction (涤痰汤) on chronic intermittent hypoxia cognitive function and the potential function mechanism. MethodsTwenty-four Sprague-Dawley (SD) rats were randomly divided into a normal group, a model group, and a modified Ditan Decoction group, with eight rats in each group. Rats in the modified Ditan Decoction group were administered the decoction by gavage at 14.8 ml/(kg·d), while the normal group and the model group received the same dose of normal saline. Thirty minutes after daily gavage, the rats in all three groups were placed in an intermittent hypoxia chamber. The oxygen concentration for the model group and the modified Ditan Decoction group was adjusted daily for 8 hours using a computer program to establish the model, while the normal group was exposed to the same airflow rate of ambient air. The intervention was continued for 12 weeks to establish a chronic intermittent hypoxia rat model. The Y-maze test was used to evaluate spatial working memory in the rats. Resting-state functional magnetic resonance imaging (rs-fMRI) was performed to detect whole-brain regional homogeneity (ReHo) and seed-based functional connectivity (FC). Brain regions showing significant differences in rs-fMRI were selected for further analysis. Immunofluorescence was used to detect β-amyloid (Aβ) deposition and the number of ionized calcium-binding adapter molecule 1 (IBA1)-positive microglial cells. Immunohistochemistry was employed to assess the expression of synaptophysin (SYP), the excitatory synapse marker vesicular glutamate transporter 1 (Vglut1), and the inhibitory synapse marker vesicular γ-aminobutyric acid transporter (VGAT). ResultsCompared with the normal group, the model group showed a reduced spontaneous alternation rate in the Y-maze test. The smoothed Z-score standardized regional homogeneity (SzReHo) value in the left entorhinal cortex significantly increased, and the FC value from this seed point to the left basal forebrain significantly reduced. Additionally, the model group exhibited significantly higher Aβ fluorescence intensity and Iba1 positivity in the left entorhinal cortex, decreased expression of SYP, Vglut1, and VGAT, along with an increased Vglut1/VGAT ratio (P<0.05 or P<0.01). Compared to the model group, the modified Ditan Decoction group demonstrated an increased spontaneous alternation rate, a significantly reduced SzReHo value in the left entorhinal cortex, and a significantly increased FC value from this region to the left basal forebrain. Furthermore, this group showed significantly lower Aβ fluorescence intensity and Iba1 positivity in the left entorhinal cortex, increased levels of SYP, Vglut1, and VGAT, and a decreased Vglut1/VGAT ratio (P<0.05 or P<0.01). ConclusionModified Ditan Decoction can reconstruct the projection from the left basal forebrain to the entorhinal cortex in chronic intermittent hypoxia, thereby reducing Aβ aggregation and excessive microglial activation in the left entorhinal cortex. This process improves the excitation/inhibition imbalance caused by synaptic remodeling, ultimately enhancing cognitive function in rats of chronic intermittent hypoxia.
6.Traditional Chinese Medicine Regulates Signaling Pathways Related to Precancerous Lesions of Gastric Cancer: A Review
Maofu ZHANG ; Xinyu LI ; Yanyun SHEN ; Yeyuan LIU ; Jialin ZHONG ; Lulu CHEN ; Haihong ZHAO ; Zhongyang SONG ; Zhiming ZHANG
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(4):297-306
Precancerous lesions of gastric cancer (PLGC) are a group of pathological changes caused by abnormalities in the structure, morphology, and differentiation of gastric mucosal epithelial cells. Since the early symptoms are hidden and non-specific, PLGC is not easy to be diagnosed and it has often developed into intermediate or advanced gastric cancer once being diagnosed and missed the best time for treatment. Accordingly, the incidence of this disease is increasing year by year, which lifts a heavy burden on the patients. The pathogenesis of PLGC is complex, involving inflammatory microenvironment, bile reflux, glycolysis, autophagy, and apoptosis. Currently, PLGC is mainly treated with anti-inflammatory and endoscopic therapies, which are difficult to curb the development of PLGC. Therefore, seeking a safe and effective therapy is an important topic of modern research. Traditional Chinese medicine (TCM), characterized by treatment based on syndrome differentiation and a holistic view, exerts effects via multiple pathways, mechanisms, and targets. Recent studies have confirmed that TCM can regulate the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR), Wnt/β-catenin, Sonic Hedgehog, nuclear factor-κB (NF-κB), Janus kinase/signal transducer and activator of transcription (JAK/STAT), hypoxia-inducible factor-1α (HIF-1α), neurogenic locus notch homolog protein (Notch), nuclear factor E2-related factor 2 (Nrf2) and other signaling pathways. By targeting these pathways, TCM can inhibit aerobic glycolysis, reduce oxidative stress, repair the inflammatory microenvironment, regulate cellular autophagy, and promote vascular normalization, thereby delaying or reversing PLGC. However, few researchers have systematically summarized the TCM regulation of PLGC-associated pathways. By reviewing the relevant articles at home and abroad, this paper summarized the roles of the above signaling pathways in the development of PLGC and the research progress in the regulation of signaling pathways by TCM in the treatment of PLGC, with a view to providing a new theoretical basis for the clinical research on PLGC and the drug development for this disease.
7.Factors influencing repeat blood donor lapsing in Guangzhou: based on the zero-inflated poisson regression model
Rongrong KE ; Guiyun XIE ; Xiaoxiao ZHENG ; Yingying XU ; Xiaochun HONG ; Shijie LI ; Yongshi DENG ; Jinyu SHEN ; Jinyan CHEN ; Jian OUYANG
Chinese Journal of Blood Transfusion 2025;38(1):73-78
[Objective] To analyze the influencing factors of repeat blood donor lapsing using a zero-inflated poisson regression model (ZIP). [Methods] The blood donation behavior of 12 498 whole blood donors from 2020 was tracked until December 31, 2023. The factors influencing the frequency of blood donations in a given year was analyzed using ZIP, and donors with 0 blood donation in that year were considered to have lapsed. The changes in relevant influencing factors associated with each blood donation were measured and modeled for analysis. [Results] The zero-inflated part of ZIP showed that the risk of lapsing of male blood donors was 2.24 times that of female blood donors (OR 95% CI:1.864-2.696, P<0.001); the risk of lapsing of the 35-44 age group and over 45 age group was respectively 40% (OR 95% CI:0.455-0.790, P<0.001) and 61%(OR 95% CI:0.268-0.578, P<0.001) lower than that of the under 25 age group; the risk of lapsing for those who have donated blood twice and ≥3 times was respectively 50% (OR 95% CI:0.405-0.609, P<0.001) and 81% (OR 95% CI:0.154-0.225, P<0.001) lower than that of first-time donors; the risk of lapsing of those with junior high or high school education was 1.2 times that of those with a college degree or higher (OR 95% CI:1.033-1.384, P<0.05); the risk of lapsing for the divorced group was 2.02 times that of the married group (OR 95% CI:1.445-2.820, P<0.001); the risk of lapsing for those with an income (Yuan) of 10 000 to 50 000, 50 000 to 100 000 and more than 100 000 was respectively 0.67 (OR 95% CI:0.552-0.818, P<0.001), 0.72 (OR 95% CI:0.591-0.884, P=0.002) and 0.67 (OR 95% CI:0.535-0.834, P<0.001) times that of those with an income (Yuan) of less than 10 000. The results of the Poisson part are consistent with the results of the zero-inflated part in terms of age and education level. [Conclusion] Blood donor lapsing is overall related to factors such as gender, age, donation frequency, education, marital status and family income. It's essential to care for those blood donors prone to lapse to retain more regular blood donors.
8.Overview of the amendments and revisions to the General Technical Requirements adopted by the Volume Ⅳ of the Chinese Pharmacopoeia 2025 Edition
ZHANG Jun ; NING Baoming ; WEI Shifeng ; SHEN Haoyu ; SHANG Yue ; ZHU Ran ; XU Xinyi ; CHEN Lei ; LIU Tingting ; MA Shuangcheng
Drug Standards of China 2025;26(1):034-044
To introduce the general thinking, guidelines, work objectives and elaboration process of the general technical requirements adopted by volume Ⅳ of the Chinese Pharmacopoeia 2025 Edition, and to summarize and figure out the main characteristics on dosage forms, physico-chemical testing, microbial and biological testing, reference standards and guidelines The newly revised general chapters of pharmacopoeia give full play to the normative and guiding role of the Chinese Pharmacopoeia standard, track the frontier dynamics of international drug regulatory science and the elaboration of monographs, expand the application of state-of-the-art technologies, and steadily promote the harmonization and unification with the ICH guidelines; further enhance the overall capacity of TCM quality control, actively implement the 3 R principles on animal experiments, and practice the concept of environmental-friendly; replace and/or reduce the use of toxic and hazardous reagents, strengthen the requirements of drug safety control This paper aims to provide a full-view perspective for the comprehensive, correct understanding and accurate implementation of general technical requirements included in the Chinese Pharmacopoeia 2025 Edition.
9.Effect of Complanatoside A on the apoptosis of articular chondrocytes
Lu YIN ; Chuanfeng JIANG ; Junjie CHEN ; Ming YI ; Zihe WANG ; Houyin SHI ; Guoyou WANG ; Huarui SHEN
Chinese Journal of Tissue Engineering Research 2025;29(8):1541-1547
BACKGROUND:Chondrocyte apoptosis is an important factor in the development of osteoarthritis,and Complanatoside A has a flavonoid effect,which can inhibit apoptosis of various cells,but its effect on chondrocyte apoptosis and the mechanism of action are not clear. OBJECTIVE:To investigate the intrinsic association and mechanism of Complanatoside A in chondrocyte apoptosis based on the Wnt/β-catenin signaling pathway. METHODS:(1)The cartilage tissues of the femur and tibia transected during knee arthroplasty were collected,and chondrocytes were isolated,cultured in vitro,and identified.(2)Cell counting kit-8 was used to detect the optimal intervention concentration of Complanatoside A in the concentration range of 0-160 μmol/L.(3)Chondrocytes were divided into blank group,sodium nitroprusside(1.5 mmol/L)-induced group,and sodium nitroprusside(1.5 mmol/L)+Complanatoside A(5 μmol/L)group.The viability and apoptosis rate of the cells in each group were detected by cell counting kit-8 and flow cytometry.The expression of type Ⅱ collagen and SOX9 was detected by immunofluorescence staining.The expression of apoptosis-related proteins and Wnt/β-catenin pathway proteins was detected by western blot assay. RESULTS AND CONCLUSION:The cells extracted in vitro were cultured and stained,and were clearly identified as chondrocytes.Complanatoside A had no obvious cytotoxicity to chondrocytes in the concentration range of 0-80 μmol/L,and significantly improved the chondrocyte viability in the concentration range of 2.5-10 μmol/L,especially when the concentration was 5 μmol/L.The apoptotic rate of chondrocytes was higher in the sodium nitroprusside-induced group than the blank control group,while the apoptotic rate was lower in the sodium nitroprusside+Complanatoside A group than the sodium nitroprusside-induced group.The fluorescence intensity of type Ⅱ collagen and SOX9 in chondrocytes was weaker in the sodium nitroprusside-induced group than the blank control group,while the fluorescence intensity of type Ⅱ collagen and SOX9 in the sodium nitroprusside+Complanatoside A group was higher than that of the sodium nitroprusside-induced group.In the sodium nitroprusside-induced group,the protein expression of Bax,Caspase-3,matrix metalloproteinase 13,Wnt3a,Wnt5a and β-catenin was higher than that of the blank control group,while the protein expression of Bcl-2 was lower than that of the blank control group.In the sodium nitroprusside+Complanatoside A group,except for the protein expression of Bcl-2 which was higher than that of the sodium nitroprusside-induced group,the expression of the other aforementioned proteins was lower than that of the sodium nitroprusside-induced group.To conclude,Complanatoside A has a certain inhibitory effect on chondrocyte apoptosis,which could regulate apoptosis-related proteins and promote the expression of chondrocyte regulatory factors,and presumably might play a role through inhibiting the Wnt/β-catenin signaling pathway.
10.Finite element analysis of various root shield thicknesses in maxillary central incisor socket-shield technique
Guangneng CHEN ; Siyang LUO ; Mei WANG ; Bin YE ; Jiawen CHEN ; Yin LIU ; Yuwen ZUO ; Xianyu HE ; Jiajin SHEN ; Minxian MA
Chinese Journal of Tissue Engineering Research 2025;29(10):2052-2060
BACKGROUND:Socket-shield technique can effectively maintain labial soft and hard tissues,but the incidence of postoperative complications such as exposure and displacement of root shield is relatively high.It is speculated that the root shield may be exposed and displaced due to excessive load after long-term function of dental implants. OBJECTIVE:Through three-dimensional finite element analysis,we aim to study the influence of varying root shield thicknesses on the stress distribution,equivalent stress peaks,and displacement in the root shield,periodontal ligaments,implant,and surrounding alveolar bone under normal occlusal loading.We also attempt to analyze the correlation between the thickness of the root shield and occurrence of mechanical events such as root shield exposure,displacement,and fracture. METHODS:Cone-beam CT data of a patient who met the indication standard of socket-shield technique for maxillary central incisor were retrieved from database.Reverse engineering techniques were used to build models of the maxillary bone and root shield,while forward engineering was used to create models for the implant components based on their parameters.Models depicting various root shield thicknesses(0.5,1.0,1.5,and 2.0 mm)were created using Solidworks 2022 software.ANSYS Workbench 2021 software was then used to simulate and analyze the effects of varying root shield thicknesses on stress distribution,equivalent stress peaks,and displacement of the root shields,periodontal ligaments,implants,and surrounding alveolar bone under normal occlusion. RESULTS AND CONCLUSION:(1)In all root shield models,the stress was concentrated on the palatal cervical side,both sides of the edges and the lower edge of the labial side.As the thickness of the root shield increased,the equivalent stress peak and displacement showed a decreasing trend.The 0.5 mm thickness model produced a stress concentration of 176.20 MPa,which exceeded the yield strength(150 MPa)of tooth tissue.(2)The periodontal ligament stress in each group was concentrated in the neck margin and upper region.With the increase of root shield thickness,the equivalent stress peak and displacement of periodontal ligament showed a decreasing trend.(3)Implant stress in all models was concentrated in the neck of the implant and the joint of the implant-repair abutment,and the labial side was more concentrated than the palatal side.With the increase of root shield thickness,the equivalent stress peak of the implant in the model showed an increasing trend.(4)In each group of models,stress of cortical bone concentrated around the neck of the implant and the periphery of the root shield,and the labial side was more concentrated than the palatal side.With the increase of the thickness of the root shield,the equivalent stress peak around the root shield decreased;the peak value of the equivalent stress of the bone around the neck of the implant showed an increasing trend.In the model,the stress of cancellous bone was mainly concentrated around the neck of the lip of the implant,the top of the thread,the root tip and the lower margin of the root shield,and the labial side was more concentrated than the palatal side.With the increase of the thickness of the root shield,the peak value of the equivalent stress of the bone around the root shield in the model showed a decreasing trend.The minimum principal stress of cortical bone in each group of models was concentrated around the neck of the implant,exhibiting a fan-shaped distribution.As the thickness of the root shield increased,the minimum principal stress of cortical bone showed an increasing trend.(5)These results indicate that different thicknesses of the root shield have different biomechanical effects.The root shield with a thickness of 0.5 mm is easy to fracture.For patients with sufficient bone width,the root shield with a thickness of 2.0 mm is an option to reduce the risk of complications such as root shield exposure,fracture,and displacement.Meanwhile,it should be taken into account to protect the periodontal ligament in the preparation process,and rounding treatments ought to be carried out on both sides and the lower edge of the root shield.


Result Analysis
Print
Save
E-mail