All-ceramic restorations have had a more limited life expectancy than metal ceramic restorations because of their low strength. Their relatively lower strength and resistance to fracture have restricted the use of all-ceramic crowns to anterior applications where occlusal loads are lower. But there ...
All-ceramic restorations have had a more limited life expectancy than metal ceramic restorations because of their low strength. Their relatively lower strength and resistance to fracture have restricted the use of all-ceramic crowns to anterior applications where occlusal loads are lower. But there has been increasing interest in all-ceramic restorations because patients are primarily concerned with improved esthetics. Many efforts have been made to in prove the mechanical properties of dental ceramics. This study was designed to elucidate the influence of the luting agent on the strength of the Empress 2 crown (staining technique) cemented on human teeth. Seventy extracted human permanent molar teeth were chosen. Teeth were prepared for Empress 2 crowns with milling machine on a surveyor. A dental bur was placed in the mandrel that was positioned so that the long axis of the bur was perpendicular to the surveyor base. Dimensions of the Empress 2 crown preparation were $6^{\circ}$ taper on each side, $1.5{\pm}0.1mm$ shoulder margin, and 4mm crown height. The luting cements used in this study were as follow: 1. Uncemented 2. Zinc phosphate cements (Confi-Dental) 3. Conventional glass ionomer cement : Fuji 1 (GC) 4. Resin-modified glass ionomer cements : Fuji plus (GC) 5. Adhesive cements : Panavia F (Kuralay), Variolink II (Vivadent), Choice (Bisco). Fracture test using Instron. The crowns were loaded in compressive force to evaluate the effect of these cements on the breaking strength of these all-ceramic crowns. A steel ball with a diameter of 4mm was placed on the occlusal surface and load was applied to the steel ball by a cylindrical bolt with a crosshead speed of 0.5mm per minute until fracture occurred. The fractured surface was examined using Scanning Electron Microscopic Image (SEM) to discover the correlation between fracture strength and bonding capacity. Within the limitation of this in vitro study design, the results were as follows : 1. fomentations significantly increased the fracture resistance of Empress ceramic crowns compared to control. Uncemented (206.9 N): ZPC (812.9 N): Fuji 1 (879.5 N): Fuji Plus (937.7 N): Choice (1105.4 N): Variolink II (1221.1 N): Panavia F (1445.2 N). 2. Resin luting agent, treated by a silane bond enhancing agents, yielded a significant increase in fracture resistance. In some of the Panavia F group, a fracture extended into dentin. 3. According to SEM images of fractured Empress crowns, the stronger the bond at both interfaces(crown and die), the more fracture strength was acquired.
All-ceramic restorations have had a more limited life expectancy than metal ceramic restorations because of their low strength. Their relatively lower strength and resistance to fracture have restricted the use of all-ceramic crowns to anterior applications where occlusal loads are lower. But there has been increasing interest in all-ceramic restorations because patients are primarily concerned with improved esthetics. Many efforts have been made to in prove the mechanical properties of dental ceramics. This study was designed to elucidate the influence of the luting agent on the strength of the Empress 2 crown (staining technique) cemented on human teeth. Seventy extracted human permanent molar teeth were chosen. Teeth were prepared for Empress 2 crowns with milling machine on a surveyor. A dental bur was placed in the mandrel that was positioned so that the long axis of the bur was perpendicular to the surveyor base. Dimensions of the Empress 2 crown preparation were $6^{\circ}$ taper on each side, $1.5{\pm}0.1mm$ shoulder margin, and 4mm crown height. The luting cements used in this study were as follow: 1. Uncemented 2. Zinc phosphate cements (Confi-Dental) 3. Conventional glass ionomer cement : Fuji 1 (GC) 4. Resin-modified glass ionomer cements : Fuji plus (GC) 5. Adhesive cements : Panavia F (Kuralay), Variolink II (Vivadent), Choice (Bisco). Fracture test using Instron. The crowns were loaded in compressive force to evaluate the effect of these cements on the breaking strength of these all-ceramic crowns. A steel ball with a diameter of 4mm was placed on the occlusal surface and load was applied to the steel ball by a cylindrical bolt with a crosshead speed of 0.5mm per minute until fracture occurred. The fractured surface was examined using Scanning Electron Microscopic Image (SEM) to discover the correlation between fracture strength and bonding capacity. Within the limitation of this in vitro study design, the results were as follows : 1. fomentations significantly increased the fracture resistance of Empress ceramic crowns compared to control. Uncemented (206.9 N): ZPC (812.9 N): Fuji 1 (879.5 N): Fuji Plus (937.7 N): Choice (1105.4 N): Variolink II (1221.1 N): Panavia F (1445.2 N). 2. Resin luting agent, treated by a silane bond enhancing agents, yielded a significant increase in fracture resistance. In some of the Panavia F group, a fracture extended into dentin. 3. According to SEM images of fractured Empress crowns, the stronger the bond at both interfaces(crown and die), the more fracture strength was acquired.
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문제 정의
In vitro reports concerning the natural human teeth are few. So it is difThe purpose of this study was to assess the effect of the luting agent on the fracture strength of the crown. In order to do this, all ceramic crowns were placed on standardized preparations on extracted molar using various luting agents and their fracture resistance was measured.
This study is designed to elucidate the influence of the luting agent on the strength of all-ceramic crown. Care was taken to standardize production of abutment samples, storage time and conditions, preparation design, crown fabrication technique, porcelain thickness, shape of crowns, and cementation, and finally loading to fracture of the control and test groups to allow relative comparison between the experimental variables under the conditions of the study.
가설 설정
1. The use of zinc phosphate or glass ionomer cement had no significant influence on the fracture resistance of Empress ceramic crowns.
제안 방법
After fracture test, the fractured surfaces were examined using SEM(Scanning Electron Microscopic Image) to discover the correlation between fracture strength and bonding capacity.
Care was taken to standardize production of abutment samples, storage time and conditions, preparation design, crown fabrication technique, porcelain thickness, shape of crowns, and cementation, and finally loading to fracture of the control and test groups to allow relative comparison between the experimental variables under the conditions of the study. Used all-ceramic crown was the Empress 2 crown (staining technique) and human teeth were used as die material.
So it is difThe purpose of this study was to assess the effect of the luting agent on the fracture strength of the crown. In order to do this, all ceramic crowns were placed on standardized preparations on extracted molar using various luting agents and their fracture resistance was measured.
produce scattered, inconsistent results.22 This finding is consistent with those reported by other clinicians and this study, these values and rankings are similar to another study that evaluated compressive strengths of posterior crowns by vertical loading Instron machine.
대상 데이터
machine on a surveyor. A diamond bur (No. 585.8, Premier) was placed in the mandrel that was positioned so that the long axis of the bur was perpendicular to the surveyor base.
The impressions were cast with type 4 stone to fabricate working die. IPS Empress crowns were fabricated in the following manner.
데이터처리
). Duncan's multiple comparison test was used to compare the correlations among the cement variables.
The fracture load values were statistically tested by a one way analysis of variance using SPSS/ PC+software (SPSS, Chicago, IL.). Duncan's multiple comparison test was used to compare the correlations among the cement variables.
성능/효과
3. Complete adhesive bonding using a resin luting agent yielded a considerable increase of the in vitro fracture resistance of all-ceramic crowns. According to SEM images of fractured Empress crowns, this effect is ascribed to a strong bond at both interfaces, the crown-resin and the die-resin interface, simulated by tooth conditioning.
The results of this study indicates that a luting procedure that includes dentinal bonding in conjunction with a composite resin-based luting material and an etched fitting surface of ceramic provides superior resistance to fracture in all-ceramic crowns compared to crowns luted with other luting cement such as zinc phosphate cement, G.LC. or modified G.
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