1.A prediction model for sarcopenia in postmenopausal women:information analysis based on the China Health and Retirement Longitudinal Study database
Guangzheng LI ; Wei LI ; Bochun ZHANG ; Haoqin DING ; Zhongqi ZHOU ; Gang LI ; Xuezhen LIANG
Chinese Journal of Tissue Engineering Research 2026;30(4):849-857
BACKGROUND:Sarcopenia is an age-related systemic skeletal muscle disease,which is associated with a variety of adverse outcomes such as falls,functional decline,frailty,and death.Postmenopausal women are one of the high-risk groups for sarcopenia.OBJECTIVE:To develop a predictive model for assessing the risk of sarcopenia in Chinese postmenopausal women based on high-quality database.METHODS:Data for this study were derived from 2 370 postmenopausal women from the China Health and Retirement Longitudinal Study(CHARLS),and sarcopenia was assessed using the Asian Working Group on Sarcopenia 2019(AWGS2019)recommended metrics.The study cohort was randomized into a training set(70%)and a validation set(30%).Risk factors for sarcopenia in postmenopausal women were screened using the least absolute shrinkage and selection operator,ten-fold cross-validation,and logistic regression.Nomogram predicting the risk of sarcopenia in postmenopausal women was constructed based on the risk factors,and the model efficacy was evaluated by the receiver operating characteristic curve and area under the curve(AUC),calibration curve,and decision curve analysis.RESULTS AND CONCLUSION:The prevalence of sarcopenia in this study was 23.50%and age,place of residence,sleep quality,cognitive function,depression,and the number of chronic diseases were selected as predictors of sarcopenia in postmenopausal women.The nomogram model showed good discrimination between the training and validation sets,with an AUC value of 0.751(95%confidence interval=0.724-0.778,P<0.001),a specificity of 72.2%,and a sensitivity of 63.2%in the training set,and an AUC value of 0.763(95%confidence interval=0.721-0.805,P<0.001),with a specificity of 69.6%and a sensitivity of 70.8%.The calibration curve showed a relatively significant agreement between the nomogram model and the actual observations,and the decision curve analysis demonstrated broad and good clinical utility.To conclude,the nomogram to assess the risk of sarcopenia constructed based on age,place of residence,sleep quality,cognitive function,depression,and number of chronic diseases,provides an effective tool for identifying and eliminating risk factors for sarcopenia in Chinese postmenopausal women,and helps to reduce the incidence of sarcopenia.
2.A prediction model for sarcopenia in postmenopausal women:information analysis based on the China Health and Retirement Longitudinal Study database
Guangzheng LI ; Wei LI ; Bochun ZHANG ; Haoqin DING ; Zhongqi ZHOU ; Gang LI ; Xuezhen LIANG
Chinese Journal of Tissue Engineering Research 2026;30(4):849-857
BACKGROUND:Sarcopenia is an age-related systemic skeletal muscle disease,which is associated with a variety of adverse outcomes such as falls,functional decline,frailty,and death.Postmenopausal women are one of the high-risk groups for sarcopenia.OBJECTIVE:To develop a predictive model for assessing the risk of sarcopenia in Chinese postmenopausal women based on high-quality database.METHODS:Data for this study were derived from 2 370 postmenopausal women from the China Health and Retirement Longitudinal Study(CHARLS),and sarcopenia was assessed using the Asian Working Group on Sarcopenia 2019(AWGS2019)recommended metrics.The study cohort was randomized into a training set(70%)and a validation set(30%).Risk factors for sarcopenia in postmenopausal women were screened using the least absolute shrinkage and selection operator,ten-fold cross-validation,and logistic regression.Nomogram predicting the risk of sarcopenia in postmenopausal women was constructed based on the risk factors,and the model efficacy was evaluated by the receiver operating characteristic curve and area under the curve(AUC),calibration curve,and decision curve analysis.RESULTS AND CONCLUSION:The prevalence of sarcopenia in this study was 23.50%and age,place of residence,sleep quality,cognitive function,depression,and the number of chronic diseases were selected as predictors of sarcopenia in postmenopausal women.The nomogram model showed good discrimination between the training and validation sets,with an AUC value of 0.751(95%confidence interval=0.724-0.778,P<0.001),a specificity of 72.2%,and a sensitivity of 63.2%in the training set,and an AUC value of 0.763(95%confidence interval=0.721-0.805,P<0.001),with a specificity of 69.6%and a sensitivity of 70.8%.The calibration curve showed a relatively significant agreement between the nomogram model and the actual observations,and the decision curve analysis demonstrated broad and good clinical utility.To conclude,the nomogram to assess the risk of sarcopenia constructed based on age,place of residence,sleep quality,cognitive function,depression,and number of chronic diseases,provides an effective tool for identifying and eliminating risk factors for sarcopenia in Chinese postmenopausal women,and helps to reduce the incidence of sarcopenia.
3.Association between neuroimaging changes and osteonecrosis:a large sample analysis from UK Biobank and FinnGen databases
Bochun ZHANG ; Wei LI ; Guangzheng LI ; Haoqin DING ; Gang LI ; Xuezhen LIANG
Chinese Journal of Tissue Engineering Research 2025;29(30):6574-6582
BACKGROUND:With the continuous exploration of the pathogenesis of osteonecrosis,more and more research evidence shows that neuroimaging change is closely related to the onset of osteonecrosis.However,the specific causal relationship between neuroimaging change and osteonecrosis is still unclear.OBJECTIVE:To evaluate the causal relationship between neuroimaging indices and osteonecrosis using Mendelian Randomization analysis.METHODS:Neuroimaging data were obtained from the UK Biobank database in the UK,which included a total of 36 778 individuals.Osteonecrosis data were obtained from the FinnGen database in Finland,including 1 543 cases and 391 037 controls.Instrumental variables were extracted and screened from outcome factors,and two-sample Mendelian randomization analysis was performed.The data were analyzed by inverse variance weighted method,MR-Egger,weighted median method,simple model method,and weighted model method.The inverse variance weighted method was used as the main analysis method,and the other four methods were used as supplements.To verify the feasibility and stability of the data,sensitivity analysis of the results was performed.Based on the complexity of causal inference,a reverse Mendelian randomization analysis was further performed to evaluate the potential reverse causal relationship.RESULTS AND CONCLUSION:(1)The results of inverse variance weighted analysis showed that 97 neuroimaging data were positively correlated with osteonecrosis(P<0.05,OR>1);2 data were heterogeneous and 6 data had horizontal pleiotropy.95 neuroimaging phenotypes were negatively correlated with osteonecrosis(P<0.05,OR<1);5 data were heterogeneous,and 9 data had horizontal pleiotropy;2 groups of data had reverse causal relationships.(2)The two-sample Mendelian randomization analysis established the causal relationship between neuroimaging indicators and osteonecrosis in the academic community.These large sample numbers from the UK and Finland provide a new theoretical basis for the pathophysiology of osteonecrosis,and also provide ideas and methods for the prediction,screening,early diagnosis and prognosis of osteonecrosis in China,which is conducive to improving the accuracy of clinical diagnosis and the effectiveness of treatment of osteonecrosis.
4.Therapeutic effect of Cornus Cervi Colla on steroid-induced osteonecrosis of the femoral head in rat models:fecal metabolomics analysis
Jinlian CHAI ; Tiefeng SUN ; Wei LI ; Bochun ZHANG ; Guangzheng LI ; Zhongqi ZHOU ; Xuezhen LIANG ; Ping WANG
Chinese Journal of Tissue Engineering Research 2025;29(29):6187-6197
BACKGROUND:Previous studies by the research group have shown that core proteoglycan in Cornus Cervi Col la can enter the bone,promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells,and has a good repair effect on steroid-induced osteonecrosis of the femoral head.OBJECTIVE:To investigate the therapeutic effect and potential mechanism of Cornus Cervi Colla on steroid-induced osteonecrosis of the femoral head in rats by fecal non-targeted fecal metabolomics.METHODS:Thirty SD rats were randomly divided into three groups using a random number table method:the control group(n=10)was injected with normal saline into the right gluteal muscle(injected on the first 3 days of each week for 3 consecutive weeks),and was given pure water gavage(once a day for 6 consecutive weeks).The model group(n=10)was injected with methylprednisolone sodium succinate into the right gluteal muscle(injected on the first 3 days of each week for 3 consecutive weeks)to establish a steroid-induced osteonecrosis of the femoral head model,and was given pure water gavage(once a day for 6 consecutive weeks).The Cornus Cervi Co I la group(n=10)was also established with a steroid-induced osteonecrosis of the femoral head model,and was given Cornus Cervi Col la gavage(once a day for 6 consecutive weeks).After gavage,cecal feces and femoral heads were collected for fecal metabolomics analysis and bone tissue Micro-CT and hematoxylin-eosin staining,respectively.RESULTS AND CONCLUSION:(1)Metabolomics analysis results showed that there were 233 differential metabolites between the Cornus Cervi Col la and model groups,with 65 significantly differing and clearly annotated metabolites.Lipid and amino acid metabolites were significantly increased,with bile acids,sulfated steroids,ephedrine,hypoxanthine,betaine,L-carnitine,B-mouse bile acid,cytidine,4-pyridoxic acid,taurine,N-acetyl-d-glucosamine,and butyric acid being the most impacted(variable weight value VIP>5).The metabolic pathways of taurine and hypotaurine were crucial in the metabolic regulatory network(pathway impact=0.428 57).(2)Micro-CT scanning results of bone tissue showed that the femoral heads of rats in the model group and the Cornus Cervi Col la group had different degrees of damage;the femoral head contour was irregular;the trabeculae in the subchondral bone of the femoral head were missing and disordered,and some cystic structures were visible.Compared with the model group,the degree of trabecular damage in the rats of the Cornus Cervi Colla group was milder.Hematoxylin-eosin staining results showed that the trabeculae in the subchondral bone of the femoral heads of rats in the model group and the Cornus Cervi Colla group were sparse or interrupted,and the empty bone lacuna rate and adipocyte invasion were increased.Compared with the model group,the empty bone lacuna rate and adipocyte invasion in the subchondral bone of the femoral heads of rats in the Cornus Cervi Colla group were reduced.(3)These results conclude that Cornus Cervi Colla potentially mitigates steroid-induced osteonecrosis of the femoral head through the metabolic processes involving taurine and associated pathways.
5.Cathepsins and osteonecrosis:analysis based on European samples from the FinnGen Database and IEU OpenGWAS Database
Jinlian CHAI ; Tiefeng SUN ; Wei LI ; Bochun ZHANG ; Guangzheng LI ; Xuekun SHAO ; Ping WANG ; Xuezhen LIANG
Chinese Journal of Tissue Engineering Research 2025;29(24):5254-5262
BACKGROUND:Osteonecrosis is an orthopedic disease that severely limits joint function,with complex pathogenesis involving multiple risk factors.Cathepsins,as a class of enzymes that play a key role in bone metabolism,are closely related to the proliferation,differentiation of bone cells,and remodeling of the bone matrix.However,previous studies have mostly focused on descriptive analyses,lacking direct evidence of causal relationships.OBJECTIVE:To clarify the potential causal relationship between cathepsins and osteonecrosis and to explore their possible mechanisms by analyzing large-scale sample data from the FinnGen database.METHODS:We obtained osteonecrosis-related data from the FinnGen database,including R9(a total of 359 399 samples:1 385 cases and 358 014 controls)and R10 versions(a total of 392 580 samples:1 543 cases and 391 037 controls).Single nucleotide polymorphisms associated with nine cathepsins(cathepsin B,E,F,G,H,O,S,L2,and Z)were acquired from a previous study(3 301 individuals).Univariate Mendelian randomization,reverse univariate Mendelian randomization,and multivariate Mendelian randomization analyses were conducted using the inverse variance weighted method,MR-Egger method,weighted median method,simple mode method,and weighted mode method.Initially,Mendelian randomization analysis was performed using osteonecrosis data from R9.Additionally,sensitivity analyses were conducted using Cochran's Q test,MR-Egger intercept,MR-PRESSO global test,and leave-one-out analysis to check for horizontal pleiotropy and heterogeneity.Subsequently,a validation analysis study was carried out on the R10 dataset,and a meta-analysis was conducted to combine the two datasets to explore the joint effect.RESULTS AND CONCLUSION:Univariate Mendelian randomization analysis results showed that higher levels of cathepsin B were significantly associated with a reduced risk of osteonecrosis(inverse variance weighted:odds ratio(OR)=0.865,95%confidence interval(CI):0.762-0.982,P=0.025),and no reverse causal relationship was found between the nine cathepsins and osteonecrosis(P>0.05).These associations were validated by meta-analysis.Multivariate analysis,using the nine cathepsins as covariates,revealed a reverse causal relationship between the levels of cathepsin Band the risk of osteonecrosis(inverse variance weighted:OR=0.8710,95%CI:0.761-0.997,P=0.045),consistent with the results before adjustment.Sensitivity analyses based on heterogeneity and horizontal pleiotropy suggested that the results were relatively robust.This study suggests that there is a causal relationship between high levels of cathepsin B and the reduced risk of osteonecrosis,and it may serve as a biomarker for osteonecrosis,providing new directions and insights for the diagnosis and treatment of osteonecrosis.Although this study is based on data analysis of European populations,these findings have important implications for Chinese biomedical research,especially in understanding disease mechanisms,developing biomarkers,and formulating treatment strategies.They also encourage similar studies conducted on Chinese populations to explore the impact of racial and genetic background differences on the occurrence of osteonecrosis.
6.Association between neuroimaging changes and osteonecrosis:a large sample analysis from UK Biobank and FinnGen databases
Bochun ZHANG ; Wei LI ; Guangzheng LI ; Haoqin DING ; Gang LI ; Xuezhen LIANG
Chinese Journal of Tissue Engineering Research 2025;29(30):6574-6582
BACKGROUND:With the continuous exploration of the pathogenesis of osteonecrosis,more and more research evidence shows that neuroimaging change is closely related to the onset of osteonecrosis.However,the specific causal relationship between neuroimaging change and osteonecrosis is still unclear.OBJECTIVE:To evaluate the causal relationship between neuroimaging indices and osteonecrosis using Mendelian Randomization analysis.METHODS:Neuroimaging data were obtained from the UK Biobank database in the UK,which included a total of 36 778 individuals.Osteonecrosis data were obtained from the FinnGen database in Finland,including 1 543 cases and 391 037 controls.Instrumental variables were extracted and screened from outcome factors,and two-sample Mendelian randomization analysis was performed.The data were analyzed by inverse variance weighted method,MR-Egger,weighted median method,simple model method,and weighted model method.The inverse variance weighted method was used as the main analysis method,and the other four methods were used as supplements.To verify the feasibility and stability of the data,sensitivity analysis of the results was performed.Based on the complexity of causal inference,a reverse Mendelian randomization analysis was further performed to evaluate the potential reverse causal relationship.RESULTS AND CONCLUSION:(1)The results of inverse variance weighted analysis showed that 97 neuroimaging data were positively correlated with osteonecrosis(P<0.05,OR>1);2 data were heterogeneous and 6 data had horizontal pleiotropy.95 neuroimaging phenotypes were negatively correlated with osteonecrosis(P<0.05,OR<1);5 data were heterogeneous,and 9 data had horizontal pleiotropy;2 groups of data had reverse causal relationships.(2)The two-sample Mendelian randomization analysis established the causal relationship between neuroimaging indicators and osteonecrosis in the academic community.These large sample numbers from the UK and Finland provide a new theoretical basis for the pathophysiology of osteonecrosis,and also provide ideas and methods for the prediction,screening,early diagnosis and prognosis of osteonecrosis in China,which is conducive to improving the accuracy of clinical diagnosis and the effectiveness of treatment of osteonecrosis.
7.Therapeutic effect of Cornus Cervi Colla on steroid-induced osteonecrosis of the femoral head in rat models:fecal metabolomics analysis
Jinlian CHAI ; Tiefeng SUN ; Wei LI ; Bochun ZHANG ; Guangzheng LI ; Zhongqi ZHOU ; Xuezhen LIANG ; Ping WANG
Chinese Journal of Tissue Engineering Research 2025;29(29):6187-6197
BACKGROUND:Previous studies by the research group have shown that core proteoglycan in Cornus Cervi Col la can enter the bone,promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells,and has a good repair effect on steroid-induced osteonecrosis of the femoral head.OBJECTIVE:To investigate the therapeutic effect and potential mechanism of Cornus Cervi Colla on steroid-induced osteonecrosis of the femoral head in rats by fecal non-targeted fecal metabolomics.METHODS:Thirty SD rats were randomly divided into three groups using a random number table method:the control group(n=10)was injected with normal saline into the right gluteal muscle(injected on the first 3 days of each week for 3 consecutive weeks),and was given pure water gavage(once a day for 6 consecutive weeks).The model group(n=10)was injected with methylprednisolone sodium succinate into the right gluteal muscle(injected on the first 3 days of each week for 3 consecutive weeks)to establish a steroid-induced osteonecrosis of the femoral head model,and was given pure water gavage(once a day for 6 consecutive weeks).The Cornus Cervi Co I la group(n=10)was also established with a steroid-induced osteonecrosis of the femoral head model,and was given Cornus Cervi Col la gavage(once a day for 6 consecutive weeks).After gavage,cecal feces and femoral heads were collected for fecal metabolomics analysis and bone tissue Micro-CT and hematoxylin-eosin staining,respectively.RESULTS AND CONCLUSION:(1)Metabolomics analysis results showed that there were 233 differential metabolites between the Cornus Cervi Col la and model groups,with 65 significantly differing and clearly annotated metabolites.Lipid and amino acid metabolites were significantly increased,with bile acids,sulfated steroids,ephedrine,hypoxanthine,betaine,L-carnitine,B-mouse bile acid,cytidine,4-pyridoxic acid,taurine,N-acetyl-d-glucosamine,and butyric acid being the most impacted(variable weight value VIP>5).The metabolic pathways of taurine and hypotaurine were crucial in the metabolic regulatory network(pathway impact=0.428 57).(2)Micro-CT scanning results of bone tissue showed that the femoral heads of rats in the model group and the Cornus Cervi Col la group had different degrees of damage;the femoral head contour was irregular;the trabeculae in the subchondral bone of the femoral head were missing and disordered,and some cystic structures were visible.Compared with the model group,the degree of trabecular damage in the rats of the Cornus Cervi Colla group was milder.Hematoxylin-eosin staining results showed that the trabeculae in the subchondral bone of the femoral heads of rats in the model group and the Cornus Cervi Colla group were sparse or interrupted,and the empty bone lacuna rate and adipocyte invasion were increased.Compared with the model group,the empty bone lacuna rate and adipocyte invasion in the subchondral bone of the femoral heads of rats in the Cornus Cervi Colla group were reduced.(3)These results conclude that Cornus Cervi Colla potentially mitigates steroid-induced osteonecrosis of the femoral head through the metabolic processes involving taurine and associated pathways.
8.Cathepsins and osteonecrosis:analysis based on European samples from the FinnGen Database and IEU OpenGWAS Database
Jinlian CHAI ; Tiefeng SUN ; Wei LI ; Bochun ZHANG ; Guangzheng LI ; Xuekun SHAO ; Ping WANG ; Xuezhen LIANG
Chinese Journal of Tissue Engineering Research 2025;29(24):5254-5262
BACKGROUND:Osteonecrosis is an orthopedic disease that severely limits joint function,with complex pathogenesis involving multiple risk factors.Cathepsins,as a class of enzymes that play a key role in bone metabolism,are closely related to the proliferation,differentiation of bone cells,and remodeling of the bone matrix.However,previous studies have mostly focused on descriptive analyses,lacking direct evidence of causal relationships.OBJECTIVE:To clarify the potential causal relationship between cathepsins and osteonecrosis and to explore their possible mechanisms by analyzing large-scale sample data from the FinnGen database.METHODS:We obtained osteonecrosis-related data from the FinnGen database,including R9(a total of 359 399 samples:1 385 cases and 358 014 controls)and R10 versions(a total of 392 580 samples:1 543 cases and 391 037 controls).Single nucleotide polymorphisms associated with nine cathepsins(cathepsin B,E,F,G,H,O,S,L2,and Z)were acquired from a previous study(3 301 individuals).Univariate Mendelian randomization,reverse univariate Mendelian randomization,and multivariate Mendelian randomization analyses were conducted using the inverse variance weighted method,MR-Egger method,weighted median method,simple mode method,and weighted mode method.Initially,Mendelian randomization analysis was performed using osteonecrosis data from R9.Additionally,sensitivity analyses were conducted using Cochran's Q test,MR-Egger intercept,MR-PRESSO global test,and leave-one-out analysis to check for horizontal pleiotropy and heterogeneity.Subsequently,a validation analysis study was carried out on the R10 dataset,and a meta-analysis was conducted to combine the two datasets to explore the joint effect.RESULTS AND CONCLUSION:Univariate Mendelian randomization analysis results showed that higher levels of cathepsin B were significantly associated with a reduced risk of osteonecrosis(inverse variance weighted:odds ratio(OR)=0.865,95%confidence interval(CI):0.762-0.982,P=0.025),and no reverse causal relationship was found between the nine cathepsins and osteonecrosis(P>0.05).These associations were validated by meta-analysis.Multivariate analysis,using the nine cathepsins as covariates,revealed a reverse causal relationship between the levels of cathepsin Band the risk of osteonecrosis(inverse variance weighted:OR=0.8710,95%CI:0.761-0.997,P=0.045),consistent with the results before adjustment.Sensitivity analyses based on heterogeneity and horizontal pleiotropy suggested that the results were relatively robust.This study suggests that there is a causal relationship between high levels of cathepsin B and the reduced risk of osteonecrosis,and it may serve as a biomarker for osteonecrosis,providing new directions and insights for the diagnosis and treatment of osteonecrosis.Although this study is based on data analysis of European populations,these findings have important implications for Chinese biomedical research,especially in understanding disease mechanisms,developing biomarkers,and formulating treatment strategies.They also encourage similar studies conducted on Chinese populations to explore the impact of racial and genetic background differences on the occurrence of osteonecrosis.
9.Clinical application and research progress of mini-midline catheters
Jing XIANG ; Bochun CHEN ; Shengxiao LAI ; Mingjun ZHANG ; Longlong LIU ; Xide LIANG
China Medical Equipment 2024;21(11):157-162
The mini-midline catheter is a new technology for catheter placement that opens up a new field of peripheral venous access devices(PVADs)and plays an important role in the intravenous treatment of patients with fragile vasculature and difficult intravenous access(DIVA).Mini-midline catheter is more economical and easier to puncture than midline catheter,longer retention time than short cannula,lower catheter-related complications,it is the preferred solution for venous vascular access device(VAD)in short-to medium-term infusion and has been widely used in intravenous infusion abroad.Domestic research and application of this technology are still in the exploratory stage,and the specifications,guidelines and expert consensus for mini midline catheters have not yet been released,and there is a lack of standardized operation procedures,indications,contraindications and other guidelines.More studies with higher quality and multi-center linkage cooperation need to be carried out to provide a theoretical and practical basis for the formulation of industry standards for mini midline catheters in line with clinical practice.The definition,attributes,innovation,indications,advantages and disadvantages of the mini midline catheter were reviewed,so as to provide reference for clinical application.
10.Audit to assess the quality of 916 prosthetic prescriptions of removable partial dentures.
Na ZHANG ; Bochun MAO ; Yunhan DAI ; Shengkai CHEN ; Ziying YOU ; Junjing ZHANG ; Xin CHEN ; Haoyue DONG ; Li YUE ; Haiyang YU
West China Journal of Stomatology 2023;41(3):315-322
OBJECTIVES:
The objectives of this study were to assess the quality of prosthetic prescriptions of removable partial dentures (RPDs) and to analyze the current situation of the communication and information delivery between clinicians and technicians.
METHODS:
All RPD prosthetic prescriptions received by a major dental laboratory in 4 weeks were involved in a quality audit, and the prescriptions were divided into three groups in accordance with the grades of clients. The filling of prosthetic prescriptions was recorded. The items in the prescriptions for audit included the general information of the patient, the general information of the clinician, the design diagram information, other detailed information, and the return date. The prescriptions were categorized into four levels on the basis of their quality by two quality inspectors who have been working for more than 10 years.
RESULTS:
A total of 916 prescriptions were collected and assessed. The names in the general information of the patient and the clinician were filled out best, both at the rate of 97.6% (n=894). The return date was filled out worst, only at the rate of 6.4% (n=59). Of those prescriptions, 86.8% (n=795) exhibited inadequate design diagram information. The results of the quality assessment demonstrated that 74.2% of prescriptions were assessed as noncompliant ones and failed to meet the acceptable clinical quality standard.
CONCLUSIONS
At present, the overall quality of RPD prosthetic prescriptions is poor. The responsibilities of clinicians and technicians are unclear, and the communication between them is not ideal.
Humans
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Denture Design
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Denture, Partial, Removable
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Prescriptions

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