Objective To comparatively analyze the friction wear performance,fracture resistance,and displacement resistance before and after aging of full crowns made from PEEK,cobalt-chromium alloy,and zirconia,providing a theoretical basis for the future application of PEEK in crown fabrication.Methods Standard anatomical full crowns of PEEK,cobalt-chromium alloy,and zirconia were fabricated by preparing the upper first premolar and taking silicone rubber impressions,resulting in 25 crowns of each material.The crowns were divided into three groups:Group A(15 crowns,5 from each material),Group B(30 crowns,10 from each materi-al),and Group C(30 crowns,10 from each material,serving as a control).Group A underwent 120 000 chewing simulations under simulated oral physiological conditions,using a stereomicroscope and Micro-image Analysis & Process system to assess and compare wear of antagonists(opposing talc ceramic balls)and material wear.Group B underwent 10 000 thermal cycling aging tests and Group C were served as the control.Universal testing machines were used to evaluate and compare the fracture resistance and displacement re-sistance of Groups B and C.Results ①The wear heights of full crown materials were as follows:cobalt-chromium alloy(0.61±0.05)mm,zirconia(0.81±0.07)mm,and PEEK(0.96±0.04)mm,with PEEK＞zirconia＞cobalt-chromium alloy(P＜0.05).For antagonist wear,the wear heights were cobalt-chromium alloy＞zirconia＞PEEK(P＜0.05).②The fracture resistance of cobalt-chromium alloy be-fore and after aging was(3 665.645±71.166)N and(2 906.830±225.143)N,respectively;for zirconia it was(2 447.825±316.961)N and(1 829.229±72.046)N;and for PEEK crowns it was(1 632.378±53.046)N and(1 074.872±105.491)N,showing cobalt-chromi-um alloy＞zirconia＞PEEK(P＜0.05).The displacement resistance for cobalt-chromium alloy before and after aging was(1 604.630±95.680)N and(1 092.137±77.869)N;for zirconia it was(1 768.851±56.273)N and(1 381.618±62.326)N;and for PEEK crowns it was(1 148.811±70.417)N and(931.723±64.454)N,indicating zirconia＞cobalt-chromium alloy＞PEEK(P＜0.05).The aging degradation of cobalt-chromium alloy's fracture and displacement re-sistance was(758.815±157.734)N and(512.492±34.530)N,re-spectively;for zirconia,it was(618.597±251.281)N and(387.233±7.947)N;and for PEEK crowns,it was(557.506±61.950)N and(217.089±14.589)N,with anti-aging performance:PEEK＞zirconia＞cobalt-chromium alloy(P＜0.05).Conclusion The wear re-sistance,fracture resistance,and displacement resistance of PEEK meet the clinical standards for full crown materials,and PEEK demonstrates good anti-aging performance while effectively protecting opposing teeth.Therefore,PEEK has the potential to become a novel material for full crown fabrication.

Under the new educational development trends,numerous universities are actively exploring the deep integration of digital information technology and artificial intelligence(AI)technology with teaching.Through a three-phase process involving stu-dents'pre-class AI-assisted online self-learning via knowledge graphs,interactive classroom teaching between teachers and students,and post-class collaborative enhancement,we explored intelligent visualization-assisted teaching,personalized learning,and multi-di-mensional,fine-grained formative assessment to help teachers offer differentiated attention and personalized guidance,encourage stu-dents'autonomous and personalized learning,enhance students'self-study capabilities.This teaching practice has achieved remark-able results in stimulating students'learning enthusiasm,broadening their knowledge base,and enhancing their self-directed learning capabilities.

Objective To comparatively analyze the friction wear performance,fracture resistance,and displacement resistance before and after aging of full crowns made from PEEK,cobalt-chromium alloy,and zirconia,providing a theoretical basis for the future application of PEEK in crown fabrication.Methods Standard anatomical full crowns of PEEK,cobalt-chromium alloy,and zirconia were fabricated by preparing the upper first premolar and taking silicone rubber impressions,resulting in 25 crowns of each material.The crowns were divided into three groups:Group A(15 crowns,5 from each material),Group B(30 crowns,10 from each materi-al),and Group C(30 crowns,10 from each material,serving as a control).Group A underwent 120 000 chewing simulations under simulated oral physiological conditions,using a stereomicroscope and Micro-image Analysis & Process system to assess and compare wear of antagonists(opposing talc ceramic balls)and material wear.Group B underwent 10 000 thermal cycling aging tests and Group C were served as the control.Universal testing machines were used to evaluate and compare the fracture resistance and displacement re-sistance of Groups B and C.Results ①The wear heights of full crown materials were as follows:cobalt-chromium alloy(0.61±0.05)mm,zirconia(0.81±0.07)mm,and PEEK(0.96±0.04)mm,with PEEK＞zirconia＞cobalt-chromium alloy(P＜0.05).For antagonist wear,the wear heights were cobalt-chromium alloy＞zirconia＞PEEK(P＜0.05).②The fracture resistance of cobalt-chromium alloy be-fore and after aging was(3 665.645±71.166)N and(2 906.830±225.143)N,respectively;for zirconia it was(2 447.825±316.961)N and(1 829.229±72.046)N;and for PEEK crowns it was(1 632.378±53.046)N and(1 074.872±105.491)N,showing cobalt-chromi-um alloy＞zirconia＞PEEK(P＜0.05).The displacement resistance for cobalt-chromium alloy before and after aging was(1 604.630±95.680)N and(1 092.137±77.869)N;for zirconia it was(1 768.851±56.273)N and(1 381.618±62.326)N;and for PEEK crowns it was(1 148.811±70.417)N and(931.723±64.454)N,indicating zirconia＞cobalt-chromium alloy＞PEEK(P＜0.05).The aging degradation of cobalt-chromium alloy's fracture and displacement re-sistance was(758.815±157.734)N and(512.492±34.530)N,re-spectively;for zirconia,it was(618.597±251.281)N and(387.233±7.947)N;and for PEEK crowns,it was(557.506±61.950)N and(217.089±14.589)N,with anti-aging performance:PEEK＞zirconia＞cobalt-chromium alloy(P＜0.05).Conclusion The wear re-sistance,fracture resistance,and displacement resistance of PEEK meet the clinical standards for full crown materials,and PEEK demonstrates good anti-aging performance while effectively protecting opposing teeth.Therefore,PEEK has the potential to become a novel material for full crown fabrication.

Objective To assess the marginal microleakage of specimens following aging simulation of adhesive restorations for dental defects using methacryloxylethyl cetyldimethyl ammonium chloride(DMAE-CB)and nanoparticles of amorphous calcium phosphate(NACP)binder.Methods DMAE-CB and NACP were synthesized in the laboratory.Eight groups were formed by varying the mass fraction ratios of the two components in the adhesive according to previous experiments,A:binder+3％DMAE-CB+25％NACP,B:binder+4％DMAE-CB+35％NACP,C:binder+1％DMAE-CB+15％NACP,D:binder+4％DMAE-CB+15％NACP,E:binder+1％DMAE-CB+35％NACP,F:binder+3％DMAE-CB,G:binder+25％NACP,H:SBMP binder as the control group.Forty human third molars were collected and randomly divided into 8 groups to prepare standardized Class Ⅱ preparations.Subsequent-ly,dental defect adhesive restoration specimens were made by using the 8 groups of binder,and aging simulation was performed through thermal cycling.After thermal cycling,the specimens were immersed in the dye solution.Each specimen was sectioned into 4 parts of dentin tissue slices along the gingival,proximal,and occlusal walls using a low-speed cutting machine,and the depth of dye penetration was observed under a stereomicroscope and recorded according to a unified standard for microleakage level.Finally,one randomly selected adhesive specimen from each of the 8 groups was subjected to gold sputtering and observed under scanning electron microscopy(SEM)to measure the gap width between the resin and dental tissue.Results Penetration staining showed that there were no statistically significant differences in the depth of marginal microleakage between the experimental and control groups on the gingival and occlusal walls(P＞0.05).However,there was a statistically significant difference in microleakage depth between the gingival and occlusal walls(P＜0.05).Scanning electron microscopy(SEM)results,after averaging particle size measurements,revealed no statistically significant differences in the gap width between the filling restorations and dental hard tissues between the experimental and con-trol groups(P＞0.05).Conclusion Dentin adhesives modified with DMAE-CB and NACP increase antibacterial and remineralization properties without affecting marginal microleakage in adhesive restorations,providing reliable theoretical support for their clinical appli-cation.

Objective:To analyze the application effect of the case-based learning (CBL), lecture-based learning (LBL) and seminar three-track stereoscopic model in the teaching of health management for chronic diseases.Methods:In this non-randomized controlled trial, a total of 70 five-year clinical medicine major undergraduate students were continuously selected as the research subjects in the Air Force Medical University during 2023-2024 year. The students enrolled the chronic disease health management course. Thirty-five cases in 2023 were assigned to the control group, while 35 cases in 2024 were assigned to the experimental group. The control group were taught by the traditional teaching method, while experimental group were taught with a combined model of CBL, LBL, and Seminar. The number of class hours for both groups were 30, with a class frequency of 2 class hours per week. The intervention period began with the first class and ended after the last class, totaling 15 weeks. The general information, medical professional courses and basic knowledge of chronic disease health management scores in the two groups were collected before intervention. The learning effect and satisfaction rate were evaluated through teaching satisfaction score, assessment assignments, practical ability score and excellent rate, autonomous learning ability score at 15 weeks after the intervention.Results:Among the 70 participants, 37 were male and 33 were female, with a mean age of (21.00±0.27) years. Before the intervention, there was no statistically significant differences in the general information, medical professional courses and basic knowledge of chronic disease health management scores between the two groups (all P>0.05). Fifteen weeks after the intervention, the experimental group had significantly higher scores in teaching content score, teaching method score, assessment assignment, final grade, practical ability scores, excellent rate of practical ability, self-management ability score, information literacy score, and learning cooperation ability score when compared to those in the control group [(93.3±6.9) vs (80.1±7.8) points, (97.1±6.3) vs (81.0±9.6) points, (91.1±7.8) vs (80.1±8.9) points, (92.9±9.4) vs (81.8±9.8) points, (91.3±7.6) vs (80.3±8.7) points, 54.3% vs 22.9%, (27.3±4.8) vs (22.8±6.8) points, (26.9±3.9) vs (20.8±4.1) points, (35.9±8.1) vs (28.9±7.1) points] (all P<0.05). Conclusion:Implementing of CBL, LBL, and Seminar teaching model in the chronic disease health management curriculum significantly enhances teaching effectiveness and improves students' overall competencies.

Objective To assess the marginal microleakage of specimens following aging simulation of adhesive restorations for dental defects using methacryloxylethyl cetyldimethyl ammonium chloride(DMAE-CB)and nanoparticles of amorphous calcium phosphate(NACP)binder.Methods DMAE-CB and NACP were synthesized in the laboratory.Eight groups were formed by varying the mass fraction ratios of the two components in the adhesive according to previous experiments,A:binder+3％DMAE-CB+25％NACP,B:binder+4％DMAE-CB+35％NACP,C:binder+1％DMAE-CB+15％NACP,D:binder+4％DMAE-CB+15％NACP,E:binder+1％DMAE-CB+35％NACP,F:binder+3％DMAE-CB,G:binder+25％NACP,H:SBMP binder as the control group.Forty human third molars were collected and randomly divided into 8 groups to prepare standardized Class Ⅱ preparations.Subsequent-ly,dental defect adhesive restoration specimens were made by using the 8 groups of binder,and aging simulation was performed through thermal cycling.After thermal cycling,the specimens were immersed in the dye solution.Each specimen was sectioned into 4 parts of dentin tissue slices along the gingival,proximal,and occlusal walls using a low-speed cutting machine,and the depth of dye penetration was observed under a stereomicroscope and recorded according to a unified standard for microleakage level.Finally,one randomly selected adhesive specimen from each of the 8 groups was subjected to gold sputtering and observed under scanning electron microscopy(SEM)to measure the gap width between the resin and dental tissue.Results Penetration staining showed that there were no statistically significant differences in the depth of marginal microleakage between the experimental and control groups on the gingival and occlusal walls(P＞0.05).However,there was a statistically significant difference in microleakage depth between the gingival and occlusal walls(P＜0.05).Scanning electron microscopy(SEM)results,after averaging particle size measurements,revealed no statistically significant differences in the gap width between the filling restorations and dental hard tissues between the experimental and con-trol groups(P＞0.05).Conclusion Dentin adhesives modified with DMAE-CB and NACP increase antibacterial and remineralization properties without affecting marginal microleakage in adhesive restorations,providing reliable theoretical support for their clinical appli-cation.

Under the new educational development trends,numerous universities are actively exploring the deep integration of digital information technology and artificial intelligence(AI)technology with teaching.Through a three-phase process involving stu-dents'pre-class AI-assisted online self-learning via knowledge graphs,interactive classroom teaching between teachers and students,and post-class collaborative enhancement,we explored intelligent visualization-assisted teaching,personalized learning,and multi-di-mensional,fine-grained formative assessment to help teachers offer differentiated attention and personalized guidance,encourage stu-dents'autonomous and personalized learning,enhance students'self-study capabilities.This teaching practice has achieved remark-able results in stimulating students'learning enthusiasm,broadening their knowledge base,and enhancing their self-directed learning capabilities.

Objective:To analyze the application effect of the case-based learning (CBL), lecture-based learning (LBL) and seminar three-track stereoscopic model in the teaching of health management for chronic diseases.Methods:In this non-randomized controlled trial, a total of 70 five-year clinical medicine major undergraduate students were continuously selected as the research subjects in the Air Force Medical University during 2023-2024 year. The students enrolled the chronic disease health management course. Thirty-five cases in 2023 were assigned to the control group, while 35 cases in 2024 were assigned to the experimental group. The control group were taught by the traditional teaching method, while experimental group were taught with a combined model of CBL, LBL, and Seminar. The number of class hours for both groups were 30, with a class frequency of 2 class hours per week. The intervention period began with the first class and ended after the last class, totaling 15 weeks. The general information, medical professional courses and basic knowledge of chronic disease health management scores in the two groups were collected before intervention. The learning effect and satisfaction rate were evaluated through teaching satisfaction score, assessment assignments, practical ability score and excellent rate, autonomous learning ability score at 15 weeks after the intervention.Results:Among the 70 participants, 37 were male and 33 were female, with a mean age of (21.00±0.27) years. Before the intervention, there was no statistically significant differences in the general information, medical professional courses and basic knowledge of chronic disease health management scores between the two groups (all P>0.05). Fifteen weeks after the intervention, the experimental group had significantly higher scores in teaching content score, teaching method score, assessment assignment, final grade, practical ability scores, excellent rate of practical ability, self-management ability score, information literacy score, and learning cooperation ability score when compared to those in the control group [(93.3±6.9) vs (80.1±7.8) points, (97.1±6.3) vs (81.0±9.6) points, (91.1±7.8) vs (80.1±8.9) points, (92.9±9.4) vs (81.8±9.8) points, (91.3±7.6) vs (80.3±8.7) points, 54.3% vs 22.9%, (27.3±4.8) vs (22.8±6.8) points, (26.9±3.9) vs (20.8±4.1) points, (35.9±8.1) vs (28.9±7.1) points] (all P<0.05). Conclusion:Implementing of CBL, LBL, and Seminar teaching model in the chronic disease health management curriculum significantly enhances teaching effectiveness and improves students' overall competencies.

Objective:To investigate the effect of water intake on bladder filling time before embryo transfer.Methods:A total of 189 patients were collected from February to June 2023 who were to undergo embryo transfer in Guangdong Women and Children Hospital. The patients were divided into group A ( n=61), group B ( n=64) and group C ( n=64) using a random number table and they were respectively given 300 mL, 500 mL and 700 mL water to drink. Abdominal ultrasound was performed every 15 min, a total of 1-5 times, from 45 min after drinking water until the bladder filling. The bladder filling time and bladder volume were collected. Kaplan-Meier method was used to compare the difference of bladder filling time among the three groups. The multivariate Cox regression was used to analyze factors of bladder filling time. Results:The cumulative bladder filling rates of group A, group B and group C at 105 min after drinking water were 57.4% (35/61), 90.6% (58/64) and 98.4% (63/64), respectively, and the median survival time (95% CI) of bladder filling was 105.0 (89.9-120.1) min, 60.0 (55.4-64.7) min and 60.0 (55.4-64.6) min, respectively. Pairwise comparison of Kaplan-Meier analysis revealed that the bladder filling time of group A was longer than that of group B and group C ( P<0.001), and there was no statistically significant difference between group B and group C ( P>0.05). The results of age-stratification analysis showed that the bladder filling time of younger patients in group A [90.0 (75.2-104.8) min] was longer than that in group B [60.0 (55.8-64.2) min, P<0.001] and group C [60.0 (55.1-64.8) min, P<0.001], and there was no statistical significance between group B and group C ( P>0.05); the bladder filling time of older patients in group C [60.0 (59.1-70.9) min] was shorter than that in group A [105.0 (89.9-120.1) min, P<0.001] and group B [75.0 (64.3-85.7) min, P=0.027], there was no statistical significance between group A and group B ( P>0.05). Multivariate Cox regression analysis showed that taking group A as reference, the hazard ratio ( HR, 95% CI) of groups B and C were 2.71 (1.78-4.21) and 3.23 (2.10-4.96), both P<0.001. The HR (95% CI) of the elderly patients was 0.69 (0.49-0.99), P=0.044. Conclusion:Water intake and age are independent factors affecting bladder filling time in embryo transfer patients. Patients are recommended to drink 500 mL of water 75 min before embryo transfer and appropriately increase the amount of water or extend the bladder preparation time after drinking water for elderly patients.

Objective:To investigate the effect of water intake on bladder filling time before embryo transfer.Methods:A total of 189 patients were collected from February to June 2023 who were to undergo embryo transfer in Guangdong Women and Children Hospital. The patients were divided into group A ( n=61), group B ( n=64) and group C ( n=64) using a random number table and they were respectively given 300 mL, 500 mL and 700 mL water to drink. Abdominal ultrasound was performed every 15 min, a total of 1-5 times, from 45 min after drinking water until the bladder filling. The bladder filling time and bladder volume were collected. Kaplan-Meier method was used to compare the difference of bladder filling time among the three groups. The multivariate Cox regression was used to analyze factors of bladder filling time. Results:The cumulative bladder filling rates of group A, group B and group C at 105 min after drinking water were 57.4% (35/61), 90.6% (58/64) and 98.4% (63/64), respectively, and the median survival time (95% CI) of bladder filling was 105.0 (89.9-120.1) min, 60.0 (55.4-64.7) min and 60.0 (55.4-64.6) min, respectively. Pairwise comparison of Kaplan-Meier analysis revealed that the bladder filling time of group A was longer than that of group B and group C ( P<0.001), and there was no statistically significant difference between group B and group C ( P>0.05). The results of age-stratification analysis showed that the bladder filling time of younger patients in group A [90.0 (75.2-104.8) min] was longer than that in group B [60.0 (55.8-64.2) min, P<0.001] and group C [60.0 (55.1-64.8) min, P<0.001], and there was no statistical significance between group B and group C ( P>0.05); the bladder filling time of older patients in group C [60.0 (59.1-70.9) min] was shorter than that in group A [105.0 (89.9-120.1) min, P<0.001] and group B [75.0 (64.3-85.7) min, P=0.027], there was no statistical significance between group A and group B ( P>0.05). Multivariate Cox regression analysis showed that taking group A as reference, the hazard ratio ( HR, 95% CI) of groups B and C were 2.71 (1.78-4.21) and 3.23 (2.10-4.96), both P<0.001. The HR (95% CI) of the elderly patients was 0.69 (0.49-0.99), P=0.044. Conclusion:Water intake and age are independent factors affecting bladder filling time in embryo transfer patients. Patients are recommended to drink 500 mL of water 75 min before embryo transfer and appropriately increase the amount of water or extend the bladder preparation time after drinking water for elderly patients.