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 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 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 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 Based on the PDCA cycle theory,it explores the application mode of scenario simulation teaching method in clinical basic skills training.Methods The 96 students majoring in clinical medicine from the First Af-filiated Hospital of Harbin Medical University in 2019 were selected as the research objects,and the experimental group and the control group were set up respectively,with 48 students in each group,and skills training was car-ried out from March to December 2022.The control group was trained in the traditional way,and the experimental group was trained in the scenario simulation teaching method based on the PDCA cycle.The training effect and training satisfaction of the control group and the experimental group were compared and analyzed.Results In the sur-vey of the training effect of the students in the experimental group,the evaluation results of the basic clinical skills operation were higher than those in the control group,and the difference between the two groups was statistically significant(P＜0.01).In terms of the appropriate and safe operation mode,There was no significant difference be-tween the two groups(P＞0.05).In the training satisfaction survey,students in the experimental group were signifi-cantly more satisfied with the training than those students who are in the control group.The difference was statistical-ly significant(P＜0.01).Conclusion The application of scenario simulation teaching method based on PDCA cycle in clinical basic skills training helps to improve the quality of clinical basic skills training and student satisfaction.

Objective Based on the PDCA cycle theory,it explores the application mode of scenario simulation teaching method in clinical basic skills training.Methods The 96 students majoring in clinical medicine from the First Af-filiated Hospital of Harbin Medical University in 2019 were selected as the research objects,and the experimental group and the control group were set up respectively,with 48 students in each group,and skills training was car-ried out from March to December 2022.The control group was trained in the traditional way,and the experimental group was trained in the scenario simulation teaching method based on the PDCA cycle.The training effect and training satisfaction of the control group and the experimental group were compared and analyzed.Results In the sur-vey of the training effect of the students in the experimental group,the evaluation results of the basic clinical skills operation were higher than those in the control group,and the difference between the two groups was statistically significant(P＜0.01).In terms of the appropriate and safe operation mode,There was no significant difference be-tween the two groups(P＞0.05).In the training satisfaction survey,students in the experimental group were signifi-cantly more satisfied with the training than those students who are in the control group.The difference was statistical-ly significant(P＜0.01).Conclusion The application of scenario simulation teaching method based on PDCA cycle in clinical basic skills training helps to improve the quality of clinical basic skills training and student satisfaction.

Objective Based on the PDCA cycle theory,it explores the application mode of scenario simulation teaching method in clinical basic skills training.Methods The 96 students majoring in clinical medicine from the First Af-filiated Hospital of Harbin Medical University in 2019 were selected as the research objects,and the experimental group and the control group were set up respectively,with 48 students in each group,and skills training was car-ried out from March to December 2022.The control group was trained in the traditional way,and the experimental group was trained in the scenario simulation teaching method based on the PDCA cycle.The training effect and training satisfaction of the control group and the experimental group were compared and analyzed.Results In the sur-vey of the training effect of the students in the experimental group,the evaluation results of the basic clinical skills operation were higher than those in the control group,and the difference between the two groups was statistically significant(P＜0.01).In terms of the appropriate and safe operation mode,There was no significant difference be-tween the two groups(P＞0.05).In the training satisfaction survey,students in the experimental group were signifi-cantly more satisfied with the training than those students who are in the control group.The difference was statistical-ly significant(P＜0.01).Conclusion The application of scenario simulation teaching method based on PDCA cycle in clinical basic skills training helps to improve the quality of clinical basic skills training and student satisfaction.

Objective Based on the PDCA cycle theory,it explores the application mode of scenario simulation teaching method in clinical basic skills training.Methods The 96 students majoring in clinical medicine from the First Af-filiated Hospital of Harbin Medical University in 2019 were selected as the research objects,and the experimental group and the control group were set up respectively,with 48 students in each group,and skills training was car-ried out from March to December 2022.The control group was trained in the traditional way,and the experimental group was trained in the scenario simulation teaching method based on the PDCA cycle.The training effect and training satisfaction of the control group and the experimental group were compared and analyzed.Results In the sur-vey of the training effect of the students in the experimental group,the evaluation results of the basic clinical skills operation were higher than those in the control group,and the difference between the two groups was statistically significant(P＜0.01).In terms of the appropriate and safe operation mode,There was no significant difference be-tween the two groups(P＞0.05).In the training satisfaction survey,students in the experimental group were signifi-cantly more satisfied with the training than those students who are in the control group.The difference was statistical-ly significant(P＜0.01).Conclusion The application of scenario simulation teaching method based on PDCA cycle in clinical basic skills training helps to improve the quality of clinical basic skills training and student satisfaction.

Objective Based on the PDCA cycle theory,it explores the application mode of scenario simulation teaching method in clinical basic skills training.Methods The 96 students majoring in clinical medicine from the First Af-filiated Hospital of Harbin Medical University in 2019 were selected as the research objects,and the experimental group and the control group were set up respectively,with 48 students in each group,and skills training was car-ried out from March to December 2022.The control group was trained in the traditional way,and the experimental group was trained in the scenario simulation teaching method based on the PDCA cycle.The training effect and training satisfaction of the control group and the experimental group were compared and analyzed.Results In the sur-vey of the training effect of the students in the experimental group,the evaluation results of the basic clinical skills operation were higher than those in the control group,and the difference between the two groups was statistically significant(P＜0.01).In terms of the appropriate and safe operation mode,There was no significant difference be-tween the two groups(P＞0.05).In the training satisfaction survey,students in the experimental group were signifi-cantly more satisfied with the training than those students who are in the control group.The difference was statistical-ly significant(P＜0.01).Conclusion The application of scenario simulation teaching method based on PDCA cycle in clinical basic skills training helps to improve the quality of clinical basic skills training and student satisfaction.

Objective Based on the PDCA cycle theory,it explores the application mode of scenario simulation teaching method in clinical basic skills training.Methods The 96 students majoring in clinical medicine from the First Af-filiated Hospital of Harbin Medical University in 2019 were selected as the research objects,and the experimental group and the control group were set up respectively,with 48 students in each group,and skills training was car-ried out from March to December 2022.The control group was trained in the traditional way,and the experimental group was trained in the scenario simulation teaching method based on the PDCA cycle.The training effect and training satisfaction of the control group and the experimental group were compared and analyzed.Results In the sur-vey of the training effect of the students in the experimental group,the evaluation results of the basic clinical skills operation were higher than those in the control group,and the difference between the two groups was statistically significant(P＜0.01).In terms of the appropriate and safe operation mode,There was no significant difference be-tween the two groups(P＞0.05).In the training satisfaction survey,students in the experimental group were signifi-cantly more satisfied with the training than those students who are in the control group.The difference was statistical-ly significant(P＜0.01).Conclusion The application of scenario simulation teaching method based on PDCA cycle in clinical basic skills training helps to improve the quality of clinical basic skills training and student satisfaction.