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
Purpose:Myringoplasty aims to improve hearing and prevent otorrhea,making graft uptake rates and hearing crucial considerations.This study analyzed the factors associated with unsuccessful graft uptake and hearing imp...Purpose:Myringoplasty aims to improve hearing and prevent otorrhea,making graft uptake rates and hearing crucial considerations.This study analyzed the factors associated with unsuccessful graft uptake and hearing improvement to guide the selection of optimal surgical approaches for myringoplasty.Methods:We retrospectively reviewed 56 ears with chronic otitis media.All patients were followed up for>6 months after tympanic membrane closure surgery.We compared the underlay method using the transcanal approach with the inlay method using the retroauricular approach for myringoplasty in patients with chronic otitis media.The underlay and inlay methods were used for 23 and 33 ears,respectively.The primary outcomes were graft uptake rate and hearing improvement.Additionally,factors such as the location of tympanic membrane perforation,patient age,and the degree of mastoid development were evaluated.Results:The perforation rate was high when the transcanal underlay method was employed to repair perforations in the anterior inferior quadrant.Both the underlay and inlay methods significantly improved hearing.However,the success rate of the inlay method was lower.Within the cases performed using the inlay method,outcomes tended to be poorer in older age groups.There were no significant differences in surgical success rates related to mastoid development.Conclusion:The inlay method using the retroauricular approach is a favorable option for repairing perforations involving the anterior inferior quadrant.However,older patients presented lower rates of hearing improvement when the inlay method was used.展开更多
Objective: A new indirect composite restorative system with water combingpressure, light, and heat was introduced for the fabrication of inlays and onlays. Methods: Fifteendefected teeth were selected for composite re...Objective: A new indirect composite restorative system with water combingpressure, light, and heat was introduced for the fabrication of inlays and onlays. Methods: Fifteendefected teeth were selected for composite resin inlay and onlay fabrication with Tescera ATL unitequipment. The clinical trial was carried out for 3 months. Results: After 3 months test, 7parameters were checked, 15 Tescera inlays and onlays were demonstrated that exceptional esthetics,all 7 parameters were good and the patients were very satisfied. Conclusion: inlays , which weremade with Tescera ATL restorative system, are esthetics; physical properties of materials areimproved highly, and have a long-lasting durability. This restorative system is worthy to be usedand further studied in dental practice.展开更多
AIM:To provide a side-by-side analysis of the summary of safety and effectiveness data(SSED)submitted to the FDA for the KAMRA and Raindrop corneal inlays for the correction of presbyopia.METHODS:SSED reports subm...AIM:To provide a side-by-side analysis of the summary of safety and effectiveness data(SSED)submitted to the FDA for the KAMRA and Raindrop corneal inlays for the correction of presbyopia.METHODS:SSED reports submitted to the FDA for KAMRA and Raindrop were compared with respect to loss of corrected distance visual acuity(CDVA),adverse event rates,induction of astigmatism,retention of contrast sensitivity,stability of manifest refractive spherical equivalent(MRSE),and achieved monocular uncorrected near visual acuity(UNVA)at 24mo.RESULTS:Totally 442/508 of KAMRA patients and344/373 Raindrop patients remained enrolled in the clinical trials at 24mo.The proportion of KAMRA and Raindrop patients who lost≥2 lines of CDVA at 24mo was 3.4%and1%,respectively.The adverse event rate was comparable between the devices.No significant inductions of astigmatism were noted.Both technologies induced a transient myopic shift in MRSE followed by a hyperopic shift and subsequent stabilization.Totally 87%of KAMRA and 98%of Raindrop patients attained a monocular UNVA of J5(20/40)or better at 24mo,28%of KAMRA and 67%of Raindrop patients attained a monocular UNVA of J1(20/20)or better at 24mo.CONCLUSION:Both devices can be considered safe and effective,however,the results of corneal inlay implantation are mixed,and long-term patient satisfaction will likely depend on subjective expectations about the capabilities of the inlays.Variability in surgical technique and postoperative care within and between the two clinical trials diminishes the comparative power of this article.展开更多
The purpose of this study was to demonstrate the improvement of hip joint dysregulation, including pain (coxalgia), tension, and restriction of joint mobility, using a dental gold alloy inlay. The subject was a 63-yea...The purpose of this study was to demonstrate the improvement of hip joint dysregulation, including pain (coxalgia), tension, and restriction of joint mobility, using a dental gold alloy inlay. The subject was a 63-year-old man who was suffering from the abovementioned symptoms for several months. On placement of the gold alloy inlay on his chest, the joint flexibility was observed to increase, and the severity of the abovementioned symptoms decreased. When the inlay was placed in his tooth, the flexibility of the joint further increased, and all other symptoms disappeared. No side effects were observed, and the prognosis was good. We believe that these effects may be explained using the electromagnetic waves emitted by the inlay and by the restoration of biting conditions. Future multidisciplinary research focusing on possible underlying mechanisms regarding the relation between electromagnetic waves and dentistry is necessary.展开更多
In the experimental garden of the Department of Soil Bioengineering and Landscape Construction, University of Applied Life Sciences in Vienna, Austria, coarse root systems of three different brush species were complet...In the experimental garden of the Department of Soil Bioengineering and Landscape Construction, University of Applied Life Sciences in Vienna, Austria, coarse root systems of three different brush species were completely excavated and semiutomatically digitized. The species were Lonicera xylosteum, Ligustrum vulgare and Euonymus europaeus. The 3-D root architectures reveal different growth strategies between species, which are related to ecological characteristics and physical soil properties. The root architecture of Lonicera xylosteum and Ligustrum vulgare, planted in the under layer of the live slope grading, where the soil is very tight and the soil water content and fertility are relatively low, is shallow. However, the root distribution of E. europaeus, planted in the middle layer, where environmental conditions are better, is deeper. Most of the root biomass of the three species is concentrated in the 0-30 cm soil layer. A quarter of the root biomass ofLigustrum vulgare is distributed in the upper layer of the plant inlay. E. europaeus has a relatively even distribution in the 30-0 cm and 60-90 cm soil layer.展开更多
Objectives: A comparison study between ceramic full coverage FPDs & 3 designs of ceramic inlay retained FPDs regarding vertical marginal gap & retention. Materials & Methods: Twenty samples were construc- ...Objectives: A comparison study between ceramic full coverage FPDs & 3 designs of ceramic inlay retained FPDs regarding vertical marginal gap & retention. Materials & Methods: Twenty samples were construc- ted and divided into 4 groups according to the type of restorations: full coverage, inlay-shaped (occluso-pro- ximal inlay + proximal box), tub-shaped (occluso-pro- ximal inlay), and proximal box-shaped FPDs. All samples were subjected to a vertical marginal gap measurements followed by a retention test. Results: The vertical marginal gap data showed no significant difference between full coverage FPDs, the tub-shap- ed inlay retained FPDs and the proximal box-shaped inlay retained FPDs. While there was a difference between these three designs and the inlay retained FPDs. Regarding retention, the full coverage FPDs recorded higher retentive strengths and was signifi-cant difference than all inlay retained FPDs designs tested. The inlay-shaped design was significant dif-ference than the other two inlay retained FPDs de-signs. Conclusions: There was no significant differ- ence between full coverage FPDs, tub-shaped & pro- ximal box shaped inlay retained FPDs as regard ver- tical marginal discrepancies. While, the inlay-haped design showed the highest vertical marginal discrep- ancies. The premolar & molar retainers for the same type of restorations showed no difference in vertical marginal discrepancies. All measured vertical mar- ginal discrepancies were in the range of clinical ac- ceptance. The full coverage FPDs recorded higher retentive strengths than all inlay retained FPDs de- signs tested. The inlay-shaped design recorded the highest retentive strengths among the three inlay re- tained FPDs designs. There was no difference as re- gard retentive strengths between tub-shaped & pro- ximal box shaped inlay retained FPDs.展开更多
The entire roller inlayed block intelligence cold strip shape meter is developed successfully in this paper,which can stably work chronically in the cold rolling workshop,the independent innovation of the key technolo...The entire roller inlayed block intelligence cold strip shape meter is developed successfully in this paper,which can stably work chronically in the cold rolling workshop,the independent innovation of the key technology of cold strip shape measuring,the foreign technical monopoly and blockade are broken through.The structural form which is different from the international popular segmented detection roller is put forward,the entire detection roller inlayed block is developed,a group of elastic blocks in that the sense organs are installed are inlayed in the radial symmetry rectangular grooves of the detection roller body,the entire roller structure is composed of elastic pieces and the roller body,the scratch of the strip surface due to different thermal expansion of the traditional detection roller measuring unit is avoided effectively.The signal transmission form which is different form the international popular dry slip ring is put forward,the spray wet slip ring is developed,slip ring and detection roller can be taken down and installed as possibly as fast,so the maintain is convenient,while through the section auto-spray cleaning,lubrication and cooling, the service life is remarkable improved and the outside interference signal is reduced.The signal processing form which is different form the international popular gathering card is put forward,the embedded DSP shape signal processing hardware system is developed,the electromagnet,temperature,humidity and vibration's interference of industry practice to shape transmission signal can be effectively avoided,which can guarantee the instantaneity and measured precision of shape measured signal.The shape signal processing software system whose function contains error compensation,pattern recognition,establishment of the target shape and the closed-loop control calculation is built,the shape meter' computer human interaction is friendly,and function of shape meter is strong,at the same time the intellectualized level of the shape meter is improved.Now,this shape meter has been successfully applied on the 1 250 mm cold strip mill of Angang Steel Company Limited,the long-term operating testing is done,every guide line achieves the anticipative effect,the measuring precision is high and the measuring signal is stable and reliable,the shape meter is tested on high speed,big tension,changed wrap angle and big depressed complicated working conditions,any scratch of the detection roller surface and the strip surface is not appearing,it can completely adapt well to the industrial production environment,reaching the international advanced level.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.
文摘Purpose:Myringoplasty aims to improve hearing and prevent otorrhea,making graft uptake rates and hearing crucial considerations.This study analyzed the factors associated with unsuccessful graft uptake and hearing improvement to guide the selection of optimal surgical approaches for myringoplasty.Methods:We retrospectively reviewed 56 ears with chronic otitis media.All patients were followed up for>6 months after tympanic membrane closure surgery.We compared the underlay method using the transcanal approach with the inlay method using the retroauricular approach for myringoplasty in patients with chronic otitis media.The underlay and inlay methods were used for 23 and 33 ears,respectively.The primary outcomes were graft uptake rate and hearing improvement.Additionally,factors such as the location of tympanic membrane perforation,patient age,and the degree of mastoid development were evaluated.Results:The perforation rate was high when the transcanal underlay method was employed to repair perforations in the anterior inferior quadrant.Both the underlay and inlay methods significantly improved hearing.However,the success rate of the inlay method was lower.Within the cases performed using the inlay method,outcomes tended to be poorer in older age groups.There were no significant differences in surgical success rates related to mastoid development.Conclusion:The inlay method using the retroauricular approach is a favorable option for repairing perforations involving the anterior inferior quadrant.However,older patients presented lower rates of hearing improvement when the inlay method was used.
文摘Objective: A new indirect composite restorative system with water combingpressure, light, and heat was introduced for the fabrication of inlays and onlays. Methods: Fifteendefected teeth were selected for composite resin inlay and onlay fabrication with Tescera ATL unitequipment. The clinical trial was carried out for 3 months. Results: After 3 months test, 7parameters were checked, 15 Tescera inlays and onlays were demonstrated that exceptional esthetics,all 7 parameters were good and the patients were very satisfied. Conclusion: inlays , which weremade with Tescera ATL restorative system, are esthetics; physical properties of materials areimproved highly, and have a long-lasting durability. This restorative system is worthy to be usedand further studied in dental practice.
文摘AIM:To provide a side-by-side analysis of the summary of safety and effectiveness data(SSED)submitted to the FDA for the KAMRA and Raindrop corneal inlays for the correction of presbyopia.METHODS:SSED reports submitted to the FDA for KAMRA and Raindrop were compared with respect to loss of corrected distance visual acuity(CDVA),adverse event rates,induction of astigmatism,retention of contrast sensitivity,stability of manifest refractive spherical equivalent(MRSE),and achieved monocular uncorrected near visual acuity(UNVA)at 24mo.RESULTS:Totally 442/508 of KAMRA patients and344/373 Raindrop patients remained enrolled in the clinical trials at 24mo.The proportion of KAMRA and Raindrop patients who lost≥2 lines of CDVA at 24mo was 3.4%and1%,respectively.The adverse event rate was comparable between the devices.No significant inductions of astigmatism were noted.Both technologies induced a transient myopic shift in MRSE followed by a hyperopic shift and subsequent stabilization.Totally 87%of KAMRA and 98%of Raindrop patients attained a monocular UNVA of J5(20/40)or better at 24mo,28%of KAMRA and 67%of Raindrop patients attained a monocular UNVA of J1(20/20)or better at 24mo.CONCLUSION:Both devices can be considered safe and effective,however,the results of corneal inlay implantation are mixed,and long-term patient satisfaction will likely depend on subjective expectations about the capabilities of the inlays.Variability in surgical technique and postoperative care within and between the two clinical trials diminishes the comparative power of this article.
文摘The purpose of this study was to demonstrate the improvement of hip joint dysregulation, including pain (coxalgia), tension, and restriction of joint mobility, using a dental gold alloy inlay. The subject was a 63-year-old man who was suffering from the abovementioned symptoms for several months. On placement of the gold alloy inlay on his chest, the joint flexibility was observed to increase, and the severity of the abovementioned symptoms decreased. When the inlay was placed in his tooth, the flexibility of the joint further increased, and all other symptoms disappeared. No side effects were observed, and the prognosis was good. We believe that these effects may be explained using the electromagnetic waves emitted by the inlay and by the restoration of biting conditions. Future multidisciplinary research focusing on possible underlying mechanisms regarding the relation between electromagnetic waves and dentistry is necessary.
文摘In the experimental garden of the Department of Soil Bioengineering and Landscape Construction, University of Applied Life Sciences in Vienna, Austria, coarse root systems of three different brush species were completely excavated and semiutomatically digitized. The species were Lonicera xylosteum, Ligustrum vulgare and Euonymus europaeus. The 3-D root architectures reveal different growth strategies between species, which are related to ecological characteristics and physical soil properties. The root architecture of Lonicera xylosteum and Ligustrum vulgare, planted in the under layer of the live slope grading, where the soil is very tight and the soil water content and fertility are relatively low, is shallow. However, the root distribution of E. europaeus, planted in the middle layer, where environmental conditions are better, is deeper. Most of the root biomass of the three species is concentrated in the 0-30 cm soil layer. A quarter of the root biomass ofLigustrum vulgare is distributed in the upper layer of the plant inlay. E. europaeus has a relatively even distribution in the 30-0 cm and 60-90 cm soil layer.
文摘Objectives: A comparison study between ceramic full coverage FPDs & 3 designs of ceramic inlay retained FPDs regarding vertical marginal gap & retention. Materials & Methods: Twenty samples were construc- ted and divided into 4 groups according to the type of restorations: full coverage, inlay-shaped (occluso-pro- ximal inlay + proximal box), tub-shaped (occluso-pro- ximal inlay), and proximal box-shaped FPDs. All samples were subjected to a vertical marginal gap measurements followed by a retention test. Results: The vertical marginal gap data showed no significant difference between full coverage FPDs, the tub-shap- ed inlay retained FPDs and the proximal box-shaped inlay retained FPDs. While there was a difference between these three designs and the inlay retained FPDs. Regarding retention, the full coverage FPDs recorded higher retentive strengths and was signifi-cant difference than all inlay retained FPDs designs tested. The inlay-shaped design was significant dif-ference than the other two inlay retained FPDs de-signs. Conclusions: There was no significant differ- ence between full coverage FPDs, tub-shaped & pro- ximal box shaped inlay retained FPDs as regard ver- tical marginal discrepancies. While, the inlay-haped design showed the highest vertical marginal discrep- ancies. The premolar & molar retainers for the same type of restorations showed no difference in vertical marginal discrepancies. All measured vertical mar- ginal discrepancies were in the range of clinical ac- ceptance. The full coverage FPDs recorded higher retentive strengths than all inlay retained FPDs de- signs tested. The inlay-shaped design recorded the highest retentive strengths among the three inlay re- tained FPDs designs. There was no difference as re- gard retentive strengths between tub-shaped & pro- ximal box shaped inlay retained FPDs.
文摘The entire roller inlayed block intelligence cold strip shape meter is developed successfully in this paper,which can stably work chronically in the cold rolling workshop,the independent innovation of the key technology of cold strip shape measuring,the foreign technical monopoly and blockade are broken through.The structural form which is different from the international popular segmented detection roller is put forward,the entire detection roller inlayed block is developed,a group of elastic blocks in that the sense organs are installed are inlayed in the radial symmetry rectangular grooves of the detection roller body,the entire roller structure is composed of elastic pieces and the roller body,the scratch of the strip surface due to different thermal expansion of the traditional detection roller measuring unit is avoided effectively.The signal transmission form which is different form the international popular dry slip ring is put forward,the spray wet slip ring is developed,slip ring and detection roller can be taken down and installed as possibly as fast,so the maintain is convenient,while through the section auto-spray cleaning,lubrication and cooling, the service life is remarkable improved and the outside interference signal is reduced.The signal processing form which is different form the international popular gathering card is put forward,the embedded DSP shape signal processing hardware system is developed,the electromagnet,temperature,humidity and vibration's interference of industry practice to shape transmission signal can be effectively avoided,which can guarantee the instantaneity and measured precision of shape measured signal.The shape signal processing software system whose function contains error compensation,pattern recognition,establishment of the target shape and the closed-loop control calculation is built,the shape meter' computer human interaction is friendly,and function of shape meter is strong,at the same time the intellectualized level of the shape meter is improved.Now,this shape meter has been successfully applied on the 1 250 mm cold strip mill of Angang Steel Company Limited,the long-term operating testing is done,every guide line achieves the anticipative effect,the measuring precision is high and the measuring signal is stable and reliable,the shape meter is tested on high speed,big tension,changed wrap angle and big depressed complicated working conditions,any scratch of the detection roller surface and the strip surface is not appearing,it can completely adapt well to the industrial production environment,reaching the international advanced level.