Objective:To observe and analyze the clinical effect of prefabricated fiber posts and plastic fiber posts in oral repair.Methods:A total of 128 patients admitted to our hospital from January 2023 to June 2024 underwen...Objective:To observe and analyze the clinical effect of prefabricated fiber posts and plastic fiber posts in oral repair.Methods:A total of 128 patients admitted to our hospital from January 2023 to June 2024 underwent oral prosthesis treatment,of which the control group(n=64)was treated with prefabricated fiber posts and the observation group(n=64)with plastic fiber posts.The efficacy,retention rate,and complication rate of the two groups were compared.Results:The total effective rate of the observation group was 96.88%,which was significantly higher than that of the control group(84.38%)(P<0.05).The restoration retention rate in the observation group was 95.31%,which was significantly higher than that in the control group(85.94%)(P<0.05).The incidence of postoperative complications in the observation group was 4.69%,which was significantly lower than that in the control group(15.63%)(P<0.05).Conclusion:For patients with oral prostheses,the use of plastic fiber posts for treatment shows better clinical effects,effectively improving the retention rate of the prosthesis and reducing the incidence of complications.Thus,it is worthy of popularization and application.展开更多
This study aimed to evaluate the influence of quartz fiber post placement on the fracture resistance of endodontically treated premolars with different dental defects under dynamic loading.Fifty extracted single-roote...This study aimed to evaluate the influence of quartz fiber post placement on the fracture resistance of endodontically treated premolars with different dental defects under dynamic loading.Fifty extracted single-rooted mandibular premolars were randomized into five groups.Each group was prepared according to numbers of residual walls ranged from 0 to 4.Then each group was divided into two subgroups with one restored with quartz fiber posts and the other without posts.In no-post groups,gutta percha point 2 mm below cemento-enamel junction was removed.Composite resin was adapted to the well and used to shape the core directly.Each tooth was restored with a complete metal crown.Dynamic loading was carried out in a masticatory simulator with a nominal load of 50 N at 2 Hz for 300 000 loading cycles.Then a quasi-statically load was applied in a universal testing machine 306 to the long axis with a crosshead speed of 1 mm？min21until fracture.Data were analyzed with one-way analysis of variance and pairwise comparison（P,0.05）.No specimens failed during dynamic loading.The fracture resistance enhanced with the increase of numbers of coronal walls and the differences were significant（P,0.05）.Placement of fiber posts had a significant effect when fewer than two walls remained（P,0.05）,but it had no significant influence in groups with two,three or four walls（P.0.05）.Fiber post did not change failure mode,and the fracture pattern was mainly favorable.More dentin walls need to be retained in clinic.When no less than two walls remained,a fiber post is not always necessary.展开更多
Equilibrium paths of post-buckling are measured for large slenderness column specimens made of the fiber reinforced composite material. The influence of the initial curvature is investigated experimentally and compare...Equilibrium paths of post-buckling are measured for large slenderness column specimens made of the fiber reinforced composite material. The influence of the initial curvature is investigated experimentally and compared with the result of the initial post-buckling theory. Both the theoretical and experimental results reveal that the column with the initial curvature has stable post-buckling behaviors and is not sensitive to the imperfection in the form of initial curvature. The experimental results show that when the lateral buckling displacement is less than 20 percent of the column length, the experimental results agree with the results from the theory of initial post-buckling quite well, while they agree with the results from the large deflection theory in a quite large range.展开更多
Mixed matrix hollow fiber membranes（MMHFMs）filled with metal-organic frameworks（MOFs）have great potential for energy-efficient gas separation processes,but the major hurdle is polymer/MOFs interfacial defects and ...Mixed matrix hollow fiber membranes（MMHFMs）filled with metal-organic frameworks（MOFs）have great potential for energy-efficient gas separation processes,but the major hurdle is polymer/MOFs interfacial defects and membrane plasticization.Herein,lab-synthesized MIL-53 was post-functionalized by aminosilane grafting and subsequently incorporated into Ultem-1000 polymer matrix to fabricate high performance MMHFMs.SEM,DLS,XRD and TGA were performed to characterize silane-modified MIL-53（S-MIL-53）and prepared MMHFMs.Moreover,the effect of MOFs loading was systematically investigated first;then gas separation performance of MMHFMs for pure and mixed gas was evaluated under different pressures.MMHFMs containing post-functionalized S-MIL-53 achieved remarkable gas permeation properties which was better than model predictions.Compared to pure HFMs,CO2permeance of MMHFM loaded with 15%S-MIL-53 increased by 157%accompanying with 40%increase for CO2/N2selectivity,which outperformed the MMHFM filled with naked MIL-53.The pure and mixed gas permeation measurements with elevated feed pressure indicated that incorporation of S-MIL-53 also increased the resistance against CO2plasticization.This work reveals that post-modified MOFs embedded in MMHFMs facilitate the improvement of gas separation performance and suppression of membrane plasticization.展开更多
The elasto-plastic postbuckling of fiber metal laminated beams with delamination and the energy release rate along the delamination front are discussed in this paper. Considering geometrical nonlinearity, thermal envi...The elasto-plastic postbuckling of fiber metal laminated beams with delamination and the energy release rate along the delamination front are discussed in this paper. Considering geometrical nonlinearity, thermal environment and geometrical initial imperfection, the incremental nonlinear equilibrium equations of delaminated fiber metal laminated beams are established, which are solved using the differential quadrature method and iterative method. Based on these, according to the J-integral theory, the elasto-plastic energy release rate is studied. The effects of some important parameters on the elasto-plastic postbuckling behavior and energy release rate of the aramid reinforced aluminum laminated beams are discussed in details.展开更多
The aim of this study is to investigate the influence of different posts on the fracture mechanics of endodontically-treated teeth with open apex. Forty-eight human maxillary anterior teeth were collected, and the roo...The aim of this study is to investigate the influence of different posts on the fracture mechanics of endodontically-treated teeth with open apex. Forty-eight human maxillary anterior teeth were collected, and the root was transversely sectioned 12 mm under the cementoenamal junction （CEJ）. These samples were then randomly divided into two groups, i.e., minor diameter open apex root （group A） and major diameter open apex root （group B）, with mineral trioxide aggregate （MTA） placed into the apical 4 mm in the root canals. Subsequently, both groups were respectively further divided into three subgroups as follows： fiber-post （subgroup 1）, metal post （subgroup 2） and non-post （subgroup 3） group. Teeth were restored with a composite resin crown and tested by using a universal testing machine at the rate of 1 mm/min cross-head. Values of the maximum fracture resistance and failure patterns were recorded and compared among all subgroups. In addition, the changes of MTA properties were carefully examined via X-ray photography. Our results indicate that （1） In group A, the mean value of fracture resistance for teeth restored with fiber posts were statistically higher than that with either metal post or non-post; （2） In group B, there was no statistically significant difference in the mean value of fracture resistance among three subgroups; （3） No statistical significance in the mean value of fracture resistance was found between group A and group B; （4） The failure modes of most samples （58%） were irreparable; （5） MTA in two teeth developed cracks after loading tests. In conclusion, endodontically-treated teeth restored with fiber posts are more resistant to fracture than those restored with either metal posts or non-post, and most of the fracture modes are catastrophic in nature.展开更多
背景:纤维桩是具有卓越的机械性能、生物相容性和美学效果的非金属牙科修复材料,对于大范围牙齿结构缺损的根管治疗牙具有良好的修复效果。目的:综述纤维桩的分类特性及其在临床修复中的应用进展。方法:应用计算机在中国知网和PubMed数...背景:纤维桩是具有卓越的机械性能、生物相容性和美学效果的非金属牙科修复材料,对于大范围牙齿结构缺损的根管治疗牙具有良好的修复效果。目的:综述纤维桩的分类特性及其在临床修复中的应用进展。方法:应用计算机在中国知网和PubMed数据库中检索有关纤维桩的文献,中文检索词为“纤维桩,分类,牙本质肩领,修复失效,纤维桩拆除,CAD/CAM”,英文检索词为“dental fiber post,classification,ferrule,failure of repair,dental fiber post removal,CAD/CAM”,最终纳入82篇文献进行分析。结果与结论:根据纤维成分的不同,纤维桩可分为碳纤维桩、玻璃纤维桩和石英纤维桩等类型,其中玻璃纤维桩在临床实践中应用最为广泛。纤维桩的固位力和抗力与剩余牙本质肩领紧密相关,而剩余牙本质肩领的数量、高度和厚度通常决定了纤维桩修复适应证的选择。纤维桩的粘接过程具有一定的技术要求,因此,遵循规范化的操作流程显得尤为重要。尽管纤维桩具备良好的机械性能,但在临床使用过程中仍可能出现与根管不密合、松动、脱落、折断或修复失败后的拆除等问题。通过定制个性化纤维桩、选择适当的表面处理方法以及探索新材料和新技术,有望提升纤维桩的临床应用效果。展开更多
<strong>Purpose: </strong>The purpose of this study was to identify optimal post and core materials for central incisors without ferrules using three-dimensional finite element analysis and three-point ben...<strong>Purpose: </strong>The purpose of this study was to identify optimal post and core materials for central incisors without ferrules using three-dimensional finite element analysis and three-point bending tests. <strong>Methods: </strong>Stress analyses were performed with six models: cast metal post and core (MP), composite resin core alone, straight fiber-reinforced post-composite resin core (FSR), tapered fiber-reinforced post-composite resin core, straight titanium post-composite resin core (TSR), and tapered titanium post-composite resin core (TTR). A 100-N load was applied to the lingual surface at a 45° angle to the long axis of the tooth. Maximum von Mises stress distributions were calculated with finite element analysis software. Five samples each of composite resin, straight fiber-reinforced post, straight titanium post, straight fiber-reinforced post and composite resin, and straight titanium post and composite resin were subjected to three-point bending tests, followed by analysis of variance and Tukey’s multiple comparison test. <strong>Results: </strong>Stress distribution was optimal on TTR. Maximum von Mises stress on the cervical side of the post was greatest in TSR (693 MPa) and TTR (556 MPa). Maximum stress on the apical side of the post was greatest in MP (110 MPa). Maximum stress in surrounding dentin was lowest in MP (203 MPa) and TTR (250 MPa). Gap distance was smallest in MP (0.09 mm) and largest in FSR (0.26 mm). Mean maximum three-point bending force was lowest in composite resin (26.9 N/mm) and highest in titanium post and composite resin (97.1 N/mm). Titanium post bending strength was consistently greater than that of the fiber-reinforced post (p < 0.01). <strong>Conclusion:</strong> These results revealed optimal stress distribution and high bending strength with the tapered titanium post and resin combination, suggesting that this combination can most effectively prevent root or post fracture in an anterior tooth without a ferrule.展开更多
Development and testing of a serially multiplexed fiber optic sensor system is described.The sensor differs from conventional fiber optic acoustic systems,as it is capable of sensing AE emissions at several points alo...Development and testing of a serially multiplexed fiber optic sensor system is described.The sensor differs from conventional fiber optic acoustic systems,as it is capable of sensing AE emissions at several points along the length of a single fiber.Multiplexing provides for single channel detection of cracks and their locations in large structural systems. An algorithm was developed for signal recognition and tagging of the AE waveforms for detection of' crack locations,Labora- tory experiments on plain concrete beams and post-tensioned FRP tendons were pcrlormed to evaluate the crack detection capability of the sensor system.The acoustic emission sensor was able to detect initiation,growth and location of the cracks in concrete as well as in the FRP tendons.The AE system is potentially suitable lot applications involving health monitoring of structures following an earthquake.展开更多
文摘Objective:To observe and analyze the clinical effect of prefabricated fiber posts and plastic fiber posts in oral repair.Methods:A total of 128 patients admitted to our hospital from January 2023 to June 2024 underwent oral prosthesis treatment,of which the control group(n=64)was treated with prefabricated fiber posts and the observation group(n=64)with plastic fiber posts.The efficacy,retention rate,and complication rate of the two groups were compared.Results:The total effective rate of the observation group was 96.88%,which was significantly higher than that of the control group(84.38%)(P<0.05).The restoration retention rate in the observation group was 95.31%,which was significantly higher than that in the control group(85.94%)(P<0.05).The incidence of postoperative complications in the observation group was 4.69%,which was significantly lower than that in the control group(15.63%)(P<0.05).Conclusion:For patients with oral prostheses,the use of plastic fiber posts for treatment shows better clinical effects,effectively improving the retention rate of the prosthesis and reducing the incidence of complications.Thus,it is worthy of popularization and application.
文摘This study aimed to evaluate the influence of quartz fiber post placement on the fracture resistance of endodontically treated premolars with different dental defects under dynamic loading.Fifty extracted single-rooted mandibular premolars were randomized into five groups.Each group was prepared according to numbers of residual walls ranged from 0 to 4.Then each group was divided into two subgroups with one restored with quartz fiber posts and the other without posts.In no-post groups,gutta percha point 2 mm below cemento-enamel junction was removed.Composite resin was adapted to the well and used to shape the core directly.Each tooth was restored with a complete metal crown.Dynamic loading was carried out in a masticatory simulator with a nominal load of 50 N at 2 Hz for 300 000 loading cycles.Then a quasi-statically load was applied in a universal testing machine 306 to the long axis with a crosshead speed of 1 mm？min21until fracture.Data were analyzed with one-way analysis of variance and pairwise comparison（P,0.05）.No specimens failed during dynamic loading.The fracture resistance enhanced with the increase of numbers of coronal walls and the differences were significant（P,0.05）.Placement of fiber posts had a significant effect when fewer than two walls remained（P,0.05）,but it had no significant influence in groups with two,three or four walls（P.0.05）.Fiber post did not change failure mode,and the fracture pattern was mainly favorable.More dentin walls need to be retained in clinic.When no less than two walls remained,a fiber post is not always necessary.
文摘Equilibrium paths of post-buckling are measured for large slenderness column specimens made of the fiber reinforced composite material. The influence of the initial curvature is investigated experimentally and compared with the result of the initial post-buckling theory. Both the theoretical and experimental results reveal that the column with the initial curvature has stable post-buckling behaviors and is not sensitive to the imperfection in the form of initial curvature. The experimental results show that when the lateral buckling displacement is less than 20 percent of the column length, the experimental results agree with the results from the theory of initial post-buckling quite well, while they agree with the results from the large deflection theory in a quite large range.
基金the financial support from the National Natural Science Foundation of China(No.21436009)
文摘Mixed matrix hollow fiber membranes（MMHFMs）filled with metal-organic frameworks（MOFs）have great potential for energy-efficient gas separation processes,but the major hurdle is polymer/MOFs interfacial defects and membrane plasticization.Herein,lab-synthesized MIL-53 was post-functionalized by aminosilane grafting and subsequently incorporated into Ultem-1000 polymer matrix to fabricate high performance MMHFMs.SEM,DLS,XRD and TGA were performed to characterize silane-modified MIL-53（S-MIL-53）and prepared MMHFMs.Moreover,the effect of MOFs loading was systematically investigated first;then gas separation performance of MMHFMs for pure and mixed gas was evaluated under different pressures.MMHFMs containing post-functionalized S-MIL-53 achieved remarkable gas permeation properties which was better than model predictions.Compared to pure HFMs,CO2permeance of MMHFM loaded with 15%S-MIL-53 increased by 157%accompanying with 40%increase for CO2/N2selectivity,which outperformed the MMHFM filled with naked MIL-53.The pure and mixed gas permeation measurements with elevated feed pressure indicated that incorporation of S-MIL-53 also increased the resistance against CO2plasticization.This work reveals that post-modified MOFs embedded in MMHFMs facilitate the improvement of gas separation performance and suppression of membrane plasticization.
基金Project supported by the National Natural Science Foundation of China(No.11272117)
文摘The elasto-plastic postbuckling of fiber metal laminated beams with delamination and the energy release rate along the delamination front are discussed in this paper. Considering geometrical nonlinearity, thermal environment and geometrical initial imperfection, the incremental nonlinear equilibrium equations of delaminated fiber metal laminated beams are established, which are solved using the differential quadrature method and iterative method. Based on these, according to the J-integral theory, the elasto-plastic energy release rate is studied. The effects of some important parameters on the elasto-plastic postbuckling behavior and energy release rate of the aramid reinforced aluminum laminated beams are discussed in details.
基金supported by a grant from a program of research and development of Hubei Province (No. 2008-BCC 001)
文摘The aim of this study is to investigate the influence of different posts on the fracture mechanics of endodontically-treated teeth with open apex. Forty-eight human maxillary anterior teeth were collected, and the root was transversely sectioned 12 mm under the cementoenamal junction （CEJ）. These samples were then randomly divided into two groups, i.e., minor diameter open apex root （group A） and major diameter open apex root （group B）, with mineral trioxide aggregate （MTA） placed into the apical 4 mm in the root canals. Subsequently, both groups were respectively further divided into three subgroups as follows： fiber-post （subgroup 1）, metal post （subgroup 2） and non-post （subgroup 3） group. Teeth were restored with a composite resin crown and tested by using a universal testing machine at the rate of 1 mm/min cross-head. Values of the maximum fracture resistance and failure patterns were recorded and compared among all subgroups. In addition, the changes of MTA properties were carefully examined via X-ray photography. Our results indicate that （1） In group A, the mean value of fracture resistance for teeth restored with fiber posts were statistically higher than that with either metal post or non-post; （2） In group B, there was no statistically significant difference in the mean value of fracture resistance among three subgroups; （3） No statistical significance in the mean value of fracture resistance was found between group A and group B; （4） The failure modes of most samples （58%） were irreparable; （5） MTA in two teeth developed cracks after loading tests. In conclusion, endodontically-treated teeth restored with fiber posts are more resistant to fracture than those restored with either metal posts or non-post, and most of the fracture modes are catastrophic in nature.
文摘背景:纤维桩是具有卓越的机械性能、生物相容性和美学效果的非金属牙科修复材料,对于大范围牙齿结构缺损的根管治疗牙具有良好的修复效果。目的:综述纤维桩的分类特性及其在临床修复中的应用进展。方法:应用计算机在中国知网和PubMed数据库中检索有关纤维桩的文献,中文检索词为“纤维桩,分类,牙本质肩领,修复失效,纤维桩拆除,CAD/CAM”,英文检索词为“dental fiber post,classification,ferrule,failure of repair,dental fiber post removal,CAD/CAM”,最终纳入82篇文献进行分析。结果与结论:根据纤维成分的不同,纤维桩可分为碳纤维桩、玻璃纤维桩和石英纤维桩等类型,其中玻璃纤维桩在临床实践中应用最为广泛。纤维桩的固位力和抗力与剩余牙本质肩领紧密相关,而剩余牙本质肩领的数量、高度和厚度通常决定了纤维桩修复适应证的选择。纤维桩的粘接过程具有一定的技术要求,因此,遵循规范化的操作流程显得尤为重要。尽管纤维桩具备良好的机械性能,但在临床使用过程中仍可能出现与根管不密合、松动、脱落、折断或修复失败后的拆除等问题。通过定制个性化纤维桩、选择适当的表面处理方法以及探索新材料和新技术,有望提升纤维桩的临床应用效果。
文摘<strong>Purpose: </strong>The purpose of this study was to identify optimal post and core materials for central incisors without ferrules using three-dimensional finite element analysis and three-point bending tests. <strong>Methods: </strong>Stress analyses were performed with six models: cast metal post and core (MP), composite resin core alone, straight fiber-reinforced post-composite resin core (FSR), tapered fiber-reinforced post-composite resin core, straight titanium post-composite resin core (TSR), and tapered titanium post-composite resin core (TTR). A 100-N load was applied to the lingual surface at a 45° angle to the long axis of the tooth. Maximum von Mises stress distributions were calculated with finite element analysis software. Five samples each of composite resin, straight fiber-reinforced post, straight titanium post, straight fiber-reinforced post and composite resin, and straight titanium post and composite resin were subjected to three-point bending tests, followed by analysis of variance and Tukey’s multiple comparison test. <strong>Results: </strong>Stress distribution was optimal on TTR. Maximum von Mises stress on the cervical side of the post was greatest in TSR (693 MPa) and TTR (556 MPa). Maximum stress on the apical side of the post was greatest in MP (110 MPa). Maximum stress in surrounding dentin was lowest in MP (203 MPa) and TTR (250 MPa). Gap distance was smallest in MP (0.09 mm) and largest in FSR (0.26 mm). Mean maximum three-point bending force was lowest in composite resin (26.9 N/mm) and highest in titanium post and composite resin (97.1 N/mm). Titanium post bending strength was consistently greater than that of the fiber-reinforced post (p < 0.01). <strong>Conclusion:</strong> These results revealed optimal stress distribution and high bending strength with the tapered titanium post and resin combination, suggesting that this combination can most effectively prevent root or post fracture in an anterior tooth without a ferrule.
基金National Science Foundation,Grant number CMS-9900338
文摘Development and testing of a serially multiplexed fiber optic sensor system is described.The sensor differs from conventional fiber optic acoustic systems,as it is capable of sensing AE emissions at several points along the length of a single fiber.Multiplexing provides for single channel detection of cracks and their locations in large structural systems. An algorithm was developed for signal recognition and tagging of the AE waveforms for detection of' crack locations,Labora- tory experiments on plain concrete beams and post-tensioned FRP tendons were pcrlormed to evaluate the crack detection capability of the sensor system.The acoustic emission sensor was able to detect initiation,growth and location of the cracks in concrete as well as in the FRP tendons.The AE system is potentially suitable lot applications involving health monitoring of structures following an earthquake.
