In order to investigate the influence of abutment material on the stress of implant-supported all-ceramic single crown, a 3D finite element model of implant-supported mandibular first premolar was computed by COSMOS/M...In order to investigate the influence of abutment material on the stress of implant-supported all-ceramic single crown, a 3D finite element model of implant-supported mandibular first premolar was computed by COSMOS/M 2.85 software. Alumina, zirconia, and titanium were used as abutment materials respectively. Vertical 600 N and horizontal 225 N load was applied on the occlusal surface. The results show that the stress distribution of implant-supported single crown was similar for different abutment materials. Maximum stresses within the crown were higher when titanium abutment was used. Maximum stress of titanium abutment was lower than that of ceramic abutment. Within the screw and fixture, maximum stresses had no difference under vertical loading but higher as titanium abutment was used under horizontal loading. There was no difference of maximum stress within the bone when different abutment materials were used. The present findings indicate that the abutment material had no influence on the stress distribution of implant-supported all- ceramic single crown but maximum stress when the titanium abutment was lower than that of ceramic abutment.展开更多
The purpose of this study was to investigate the influence of different luting agents on the stress distribution within the crown, abutment and peri-implant bone of implant-supported all-ceramic single crown. A three-...The purpose of this study was to investigate the influence of different luting agents on the stress distribution within the crown, abutment and peri-implant bone of implant-supported all-ceramic single crown. A three-dimensional finite element model of an implant-supported single crown for the first premolar of mandible was created by COSMOS 2.85. Resin-modified glass ionomer and two different resin adhesives were used to cement the crown and abutment. Vertical 600 N and horizontal 225 N loads were applied to stimulate the condition of chewing. The stress distributions within the all-ceramic crown, abutment and peri-implant bone were analyzed. The experimental results show that the stress distributions of all-ceramic crown, abutment, implant and peri-implant bone were similar when different luting agents were used. The result of present study indicated that luting agents had no influence on the stress distributions of implant-supported all-ceramic single crown.展开更多
The purpose of the present study was to evaluate the effect ofA1203 content on the fracture property of all-ceramics ZrO2. To improve the all-ceramics ZrO2 restoration mechanics properity ,96 samples containing 0,5,10...The purpose of the present study was to evaluate the effect ofA1203 content on the fracture property of all-ceramics ZrO2. To improve the all-ceramics ZrO2 restoration mechanics properity ,96 samples containing 0,5,10 and 15 wt% of A1203 particles were prepared by cold isostatic pressing （200 MPa） and 1 550 ℃ sintered .The phase was analyzed by X-ray diffraction analysis and the bulk densities of the samples were made using Archimedes principle. Samples were randomly divided into four groups. In each group, 24 specimens were prepared so that the angle between notch and specimen＇s long axis is 90° and 60°. Notch depths were 1 mm for all samples. Samples were loaded with three-point bending method. 90° cut samples were used to measure fracture toughness while 60°cut samples were used to observe fracture curve by taking points on the fracture extension path under microscope, plotting points on coordinates, generating fitting curve by software ＂Origin＂, and analyzing the microstructure of the specimen fracture surfaces by scanning electron microscopy （SEM）.The results show that the increment ofA1203 has insignificant effect on the densification of all-ceramic ZrO2.XRD analysis shows that the specimen is comprised of t-ZrO2 and a- A1203 before fracture while fracture surface is m-ZrO2, t-ZrO2 and a-A1203. ZrO2 containing 10% A1203 has the optimum mechanical properties and unconspicuous crack propagation and distribution. The observations may provide a reference for the materials selection, shaoe design, and production orocess of all-ceramic crown and bridge.展开更多
Since the last two decades, restorative dentistry has been witnessing an increased acceptance of the use of the well-known all-ceramic materials for the fabrication of single dental restorations, such as inlays, onlay...Since the last two decades, restorative dentistry has been witnessing an increased acceptance of the use of the well-known all-ceramic materials for the fabrication of single dental restorations, such as inlays, onlays, crowns, anterior and posterior fixed partial dentures (PFPDs). These restorations certainly offer the potential for better biocompatibility coupled with superior aesthetic qualities, especially when compared with the conventional prostheses made from porcelain that is fused with metal ceramic restorations. However, brittleness and extreme sensitivity of all-ceramic materials to micro-like defects or cracks that are inherently present, or may grow, in their microstructure during different laboratory fabrication steps, during necessary clinical adjustments, or from post-placement chewing activity, remain major shortcomings of these dental restorations. In fact, many researchers are of the opinion that the improved mechanical properties can significantly improve the lifetime of all-ceramic restorations and result in enhanced reliability. Therefore, efforts of researchers, as well as manufacturers, have been directed towards the improvement of the mechanical properties in order to overcome such limitations. This article reviews the characterization of the most important mechanical properties that can delineate the behavior of all-ceramic dental materials upon loading. These include fracture mechanics, the brittle nature of ceramics, the relationship between microstructural features and fracture behavior, sources of cracks and flaws that may initiate a fracture and the effect of different fabrication procedures and/or clinical adjustments on the mechanical behavior of dental ceramics are also reviewed and discussed.展开更多
基金the National Natural Science Foundation of China (No.30801312)
文摘In order to investigate the influence of abutment material on the stress of implant-supported all-ceramic single crown, a 3D finite element model of implant-supported mandibular first premolar was computed by COSMOS/M 2.85 software. Alumina, zirconia, and titanium were used as abutment materials respectively. Vertical 600 N and horizontal 225 N load was applied on the occlusal surface. The results show that the stress distribution of implant-supported single crown was similar for different abutment materials. Maximum stresses within the crown were higher when titanium abutment was used. Maximum stress of titanium abutment was lower than that of ceramic abutment. Within the screw and fixture, maximum stresses had no difference under vertical loading but higher as titanium abutment was used under horizontal loading. There was no difference of maximum stress within the bone when different abutment materials were used. The present findings indicate that the abutment material had no influence on the stress distribution of implant-supported all- ceramic single crown but maximum stress when the titanium abutment was lower than that of ceramic abutment.
基金Funded by the National Natural Science Foundation of China(No.81100784)
文摘The purpose of this study was to investigate the influence of different luting agents on the stress distribution within the crown, abutment and peri-implant bone of implant-supported all-ceramic single crown. A three-dimensional finite element model of an implant-supported single crown for the first premolar of mandible was created by COSMOS 2.85. Resin-modified glass ionomer and two different resin adhesives were used to cement the crown and abutment. Vertical 600 N and horizontal 225 N loads were applied to stimulate the condition of chewing. The stress distributions within the all-ceramic crown, abutment and peri-implant bone were analyzed. The experimental results show that the stress distributions of all-ceramic crown, abutment, implant and peri-implant bone were similar when different luting agents were used. The result of present study indicated that luting agents had no influence on the stress distributions of implant-supported all-ceramic single crown.
基金Funded by the Technology Department Science Fund of Sichaun(No.2011GZ011520)
文摘The purpose of the present study was to evaluate the effect ofA1203 content on the fracture property of all-ceramics ZrO2. To improve the all-ceramics ZrO2 restoration mechanics properity ,96 samples containing 0,5,10 and 15 wt% of A1203 particles were prepared by cold isostatic pressing （200 MPa） and 1 550 ℃ sintered .The phase was analyzed by X-ray diffraction analysis and the bulk densities of the samples were made using Archimedes principle. Samples were randomly divided into four groups. In each group, 24 specimens were prepared so that the angle between notch and specimen＇s long axis is 90° and 60°. Notch depths were 1 mm for all samples. Samples were loaded with three-point bending method. 90° cut samples were used to measure fracture toughness while 60°cut samples were used to observe fracture curve by taking points on the fracture extension path under microscope, plotting points on coordinates, generating fitting curve by software ＂Origin＂, and analyzing the microstructure of the specimen fracture surfaces by scanning electron microscopy （SEM）.The results show that the increment ofA1203 has insignificant effect on the densification of all-ceramic ZrO2.XRD analysis shows that the specimen is comprised of t-ZrO2 and a- A1203 before fracture while fracture surface is m-ZrO2, t-ZrO2 and a-A1203. ZrO2 containing 10% A1203 has the optimum mechanical properties and unconspicuous crack propagation and distribution. The observations may provide a reference for the materials selection, shaoe design, and production orocess of all-ceramic crown and bridge.
文摘Since the last two decades, restorative dentistry has been witnessing an increased acceptance of the use of the well-known all-ceramic materials for the fabrication of single dental restorations, such as inlays, onlays, crowns, anterior and posterior fixed partial dentures (PFPDs). These restorations certainly offer the potential for better biocompatibility coupled with superior aesthetic qualities, especially when compared with the conventional prostheses made from porcelain that is fused with metal ceramic restorations. However, brittleness and extreme sensitivity of all-ceramic materials to micro-like defects or cracks that are inherently present, or may grow, in their microstructure during different laboratory fabrication steps, during necessary clinical adjustments, or from post-placement chewing activity, remain major shortcomings of these dental restorations. In fact, many researchers are of the opinion that the improved mechanical properties can significantly improve the lifetime of all-ceramic restorations and result in enhanced reliability. Therefore, efforts of researchers, as well as manufacturers, have been directed towards the improvement of the mechanical properties in order to overcome such limitations. This article reviews the characterization of the most important mechanical properties that can delineate the behavior of all-ceramic dental materials upon loading. These include fracture mechanics, the brittle nature of ceramics, the relationship between microstructural features and fracture behavior, sources of cracks and flaws that may initiate a fracture and the effect of different fabrication procedures and/or clinical adjustments on the mechanical behavior of dental ceramics are also reviewed and discussed.
