1.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.
2.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.
3.The multi-center mid-term clinical outcomes of combined complete preservation of chordal structure mitral valve replacement with total anatomic complete arterial myocardial revascularization for coronary patients with moderate-to-severe or severe ischemic mitral regurgitation
Ke GUO ; Xujun CHEN ; Baoshi ZHENG ; Chao SHI ; Keli HUANG ; Yong CAO ; Chengquan LIAO ; Jingwei CHEN ; Yu LIN ; Chengxin LIU ; Quansheng CAO ; Lin SHEN ; Zhendong WANG
Chinese Journal of Surgery 2025;63(1):58-67
Objective:To evaluate the clinical outcomes of combined complete preservation of chordal structure mitral valve replacement (C-MVR) with total anatomical arterial myocardial revascularization (TACR) in coronary patients with moderate-to-severe or severe ischemic mitral regurgitation (IMR).Methods:This is a retrospective multi-center case series study. Data were retrospectively collected from 127 patients with coronary artery disease with moderate to severe or severe IMR who received TACR with C-MVR from July 2015 to April 2024 in 13 hospitals in China. There were 90 males and 37 females, aged (56.5±10.7) years (range: 33 to 74 years). Perioperative data and follow-up data including left ventricular ejection fraction, left ventricular end-diastolic diameter, and patency rate of arterial grafts of patients were collected. Comparisons were made using paired sample t-test or χ2 test. Results:In this cohort of 127 patients, 67 underwent concurrent tricuspid valve repair. During surgery, 113 grafts of the left internal mammary artery (LIMA), 127 grafts of the left radial artery, 80 grafts of the right radial artery, and 110 grafts of the right internal mammary artery (RIMA) were harvested. The number of the distal anastomosis was 4.2±0.4 (range: 3 to 5). The aortic cross-clamp time and cardiopulmonary bypass time were (97.5±23.4) minutes (range: 90 to 161 minutes) and (145.4±19.2) minutes (range: 101 to 210 minutes), respectively. There was one operative death. Intraoperative placement of an intra-aortic balloon pump was performed in 21 patients to improve the left ventricular ejection. No sternal ischemic occurred. All patients completed follow-up, with a mean follow-up period of (64.3±7.5) months (range: 4 to 110 months). No major cerebrovascular events occurred during the follow-up period, and all patients survived. Left ventricular ejection fraction improved postoperatively (55.0%±5.3% vs. 41.0%±15.3%, t=17.23, P<0.01). The proportion of patients with New York Heart Association functional class ≤2 increased postoperatively (23.6% (30/127) vs. 87.3% (110/126), χ2=103.77, P<0.01). The proportion of patients with Canadian Cardiovascular Society Angina Classification ≤3 decreased postoperatively (4.8% (6/126) vs. 78.7% (100/127), χ2=142.19, P<0.01). The left ventricular end-diastolic diameter decreased postoperatively ((5.70±4.50) cm vs. (6.10±0.23) cm, t=12.15, P<0.01). Coronary multi-detector computed tomography angiography (MDCTA) follow-up was conducted for (60.5±11.7) months (range: 6 to 109 months) postoperatively. MDCTA confirmed the patency rates of the grafts: 96.4% (108/112) for the LIMA grafts, 88.9% (112/126) for the left radial artery grafts, 93.7% (74/79) for the right radial artery grafts, and 90.9% (100/110) for the free RIMA grafts. No significant differences in graft patency rates were observed between the arterial grafts ( χ2=5.24, P=0.155). Conclusion:The results of this multi-centre study demonstrate satisfactory mid-term results of C-MVR with TACR for the treatment of coronary artery disease with moderate to severe or severe IMR.
4.Trends in incidence and mortality of colorectal cancer and related life loss in Haishu District, Ningbo of Zhejiang Province, 2017‒2022
Yingzhuo SHEN ; Jie CHEN ; Peiling ZHANG
Shanghai Journal of Preventive Medicine 2025;37(1):60-63
ObjectiveTo analyze the trend of incidence, mortality rate and related life loss of colorectal cancer in Haishu District, Ningbo from 2017 to 2022, so as to provide a scientific basis for the prevention and treatment of colorectal cancer. MethodsThe incidence and death data of colorectal cancer among residents in Haishu District during 2017‒2022 were collected from the Ningbo Municipal Digital Disease Prevention and Control Platform. The incidence and mortality rate, the age-specific incidence and mortality rate, potential years of life lost (PYLL), potential years of life lost rate (PYLLR), and average years of life lost (AYLL) were calculated. The standardized rate was calculated based on the standardized population from the Sixth National Census in 2010, and the annual percentage change (APC) was calculated by Joinpoint Regression Program. ResultsA total of 2 595 cases of colorectal cancer were reported in Haishu District from 2017 to 2022, with a crude incidence rate of 68.23/100 000 and a standardized incidence rate of 39.72/100 000. There were no statistical differences in crude and standardized incidence rates(APC=2.288%, -0.160%,both P>0.05). In addition, a total of 898 colorectal cancer deaths were reported, with a crude mortality rate of 23.61/100 000 and a standardized mortality rate of 12.18/100 000, of which the crude mortality rate and standardized mortality rate of males showed an upward trend (APC=10.855%, 7.895%, both P<0.05). Furthermore, the crude incidence and mortality rate of colorectal cancer in males were higher than those in females (both P<0.05). The crude incidence and mortality rate of colorectal cancer in Haishu District showed an increasing trend by age (both P<0.05). PYLL caused by colorectal cancer was 7 818.52 person-years, and AYLL was 8.71 years, with a PYLLR of 2.06‰. ConclusionThe incidence and mortality rate of colorectal cancer in Haishu District are still at a high level. Colorectal cancer screening should be continued, relevant health knowledge should be facilitated and disseminated, awareness of early screening and diagnosis of colorectal cancer should be promoted, and ultimately improving the survival rate of the patients.
5.A survey of HPV and vaccine cognition and vaccination intention among primary health care workers in Shanghai
Lei CHEN ; Yuanying LU ; Yahong SHEN ; Qiaoying ZHANG ; Haiying SHI ; Minglu SHANG ; Xiao ZHANG
Journal of Public Health and Preventive Medicine 2025;36(2):89-90
Objective To understand the awareness and willingness of primary medical staff in Songjiang District, Shanghai towards human papillomavirus (HPV) and its vaccines, and to provide references for improving the vaccination willingness of HPV vaccine and primary prevention of cervical cancer. Methods From July to August 2023, a questionnaire survey was conducted among the in-service medical staff in 17 community health service centers in Songjiang District, Shanghai, using the random sampling method. Descriptive analysis, χ2 test and logistic regression were used for statistical analysis. Results A total of 951 valid questionnaires were collected during the survey. The awareness rate of HPV among medical staff was 92.74%, and the awareness rate of HPV vaccine was 93.38%. The maximum score for HPV knowledge was 6 points, with an average score of (3.99±1.34) points. The maximum score for HPV vaccine knowledge was 10 points, with an average score of (5.63±1.61) points. 881 (92.64%) medical staff were willing to receive or recommend HPV vaccination. Multivariate analysis showed that concerns about being infected with HPV (OR=2.648, 95% CI: 1.459-4.806), qualified score on HPV vaccine knowledge (OR=1.717, 95% CI: 1.012-2.912), high price burden of HPV vaccine (OR=0.343, 95% CI: 0.157-0.746), and concerns about side effects of vaccination (OR=0.443, 95% CI: 0.243-0.805) were the influencing factors for medical staff's willingness to vaccinate. Conclusion There is insufficient knowledge of HPV and its vaccines among primary medical personnel in Songjiang District, Shanghai. It is necessary to strengthen the continuing education of medical personnel through multiple channels, supplement the HPV-related knowledge system, and eliminate their concerns about vaccines.
6.Mortality and life loss due to coronary heart disease and stroke in Wujiang District of Suzhou in 2011 - 2022
Siyi GUN ; Rongyan ZHANG ; Jianxin SHEN ; Mei YANG ; Xiaochu PENG ; Jing TANG ; Mengxiang CHEN
Journal of Public Health and Preventive Medicine 2025;36(2):100-104
Objective To understand the mortality and potential life loss due to coronary heart disease (CHD) and stroke in Wujiang District, Suzhou from 2011 to 2022, and to provide strategies and basis for the prevention and treatment of CHD and stroke. Methods We collected the data of death cases due to CHD and stroke from the death monitoring system in Suzhou from 2011 to 2022. The mortality of CHD and stroke, potential years of life lost (potential years of life lost , PYLL), average years of life lost (average years of life lost , AYLL) and potential years of life lost rate (potential years of life lost rate , PYLLR) were calculated to analyze the development trend of death and disease burden of CHD and stroke. Results From 2011 to 2022, the crude mortality of CHD was 31.91/10 million, and that of stroke was 118.93/10 million. CHD and stroke mortality rates both showed an upward trend(P<0.05, a statistically significant trend). From 2011 to 2022, the mortality rate of CHD and stroke in Wujiang District increased rapidly with the increase of age. From 2011 to 2022, the disease burden caused by CHD totaled 11005 person-years, with PYLLR of 1.26% and AYLL of 12.34 years per person. The PYLL caused by stroke was 13 587.5 people-years, the PYLLR was 1.55%, and the AYLL was 8.93 years per person. PYLL, PYLLR and AYLL all decreased in women(P<0.05), with no significant change in men(P>0.05). Conclusion From 2011 to 2022, the mortality rate of CHD and stroke in Wujiang District appeared a tendency towards a rise, effective intervention and prevention measures should be taken among elderly and male residents.
7.Perceived stress and occupational burnout among hospital staff in Guangzhou tertiary hospitals
Wenli ZHOU ; Xiaoyi WU ; Yichen YE ; Liman WU ; Biyun CHEN ; Yi SHEN
Journal of Environmental and Occupational Medicine 2025;42(3):354-359
Background Staff in tertiary hospitals are a high-risk group for occupational burnout. Timely identification and precise intervention are crucial for improving healthcare service quality. However, comparative studies on perceived stress and occupational burnout among hospital staff in different positions are lacking. Objective To describe the status of perceived stress and occupational burnout among hospital staff in different positions and compare the differences, explore the relationship between perceived stress and occupational burnout, and identify the influencing factors of occupational burnout. Methods In May 2022,
8.Guangxi expert consensus on rapid comprehensive evaluation of oral dihydropyridine calcium channel blockers in the treatment of cardiovascular disease
Siru ZHOU ; Yue QIU ; Weipei SHEN ; Zhenguang HUANG ; Xiaoyu CHEN ; Hongliang ZHANG
China Pharmacy 2025;36(7):769-778
OBJECTIVE To conduct a rapid and comprehensive evaluation of commonly used oral dihydropyridine calcium channel blockers (DHP CCBs) in Guangxi, and provide scientific basis for clinical medication and drug selection in medical institutions. METHODS Based on the actual drug use data of public medical institutions at the second level and above in Guangxi Zhuang Autonomous Region, and based on the national centralized collection catalog, commonly used oral DHP CCBs were selected. The Professional Committee of Evidence-based Pharmacy of the Guangxi Pharmaceutical Association organized relevant experts from multiple medical institutions in the region to conduct a quantitative scoring of the selected oral DHP CCBs from five key dimensions of pharmaceutical characteristics, effectiveness, safety, economy, and other attributes, by referring to the Quick Guideline for Drug Evaluation and Selection in Chinese Medical Institutions (the Second Edition), combined with the latest evidence-based medical research results, and widely soliciting suggestions from clinical and pharmaceutical experts. Finally, the Guangxi Expert Consensus on Rapid Comprehensive Evaluation of Oral Dihydropyridine Calcium Channel Blockers in the Treatment of Cardiovascular Disease was formulated. RESULTS A total of 30 commonly used oral DHP CCBs were selected. Among them, Amlodipine besylate tablets (Huizhi) demonstrated superior comprehensive performance (81.79 points), excelling particularly in pharmaceutical properties, effectiveness and other attributes. The compound scores of Amlodipine besylate tablets (Chongqing Yaoyou) and Amlodipine besylate tablets (Suzhou Dongrui) ranked second and third respectively, with scores of 81.66 and 81.60 points. CONCLUSIONS This consensus can provide guidance and decision-making support for the rational clinical application of oral DHP CCBs in Guangxi Region and the selection of drug directories in medical institutions.
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.


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