Dental materials : official publication of the Academy of Dental Materials, Dec 1, 2016
The aim of this laboratory study was to evaluate the horizontal and vertical effects of the polym... more The aim of this laboratory study was to evaluate the horizontal and vertical effects of the polymerization shrinkage of three-unit temporary fixed dental prostheses (FDPs) on the position of the prepared teeth. In addition, the reduction of these effects by using different fabrication techniques was evaluated. A total of 192 temporary FDPs were fabricated using one methacrylate (MA) and two dimethacrylate (DMA) materials. Each material group (n=64) was divided into two groups according to the fabrication methods (M1: curing on the prepared teeth, M2: curing in a silicone mold). Each fabrication group was divided into four subgroups (n=8) according to the relining method used (B: no relining, S: spacer foil 300μm, DG: grinding-out with 500μm cutting depth, and FG: free grinding). The experimental apparatus consisted of two abutment teeth lowered at right angles into a silicone mold. One prepared tooth was embedded in silicone to simulate the periodontium and permit slight horizontal ...
To test the bond strength and durability after artificial aging of so-called universal primers an... more To test the bond strength and durability after artificial aging of so-called universal primers and universal multimode adhesives to lithium disilicate or zirconia ceramics. A total of 240 ceramic plates, divided into two groups, were produced and conditioned: 120 acid-etched lithium disilicate plates (IPS e.max CAD) and 120 air-abraded zirconia plates (Zenostar T). Each group was divided into five subgroups (n = 24), and a universal restorative primer or multimode universal adhesive was used for each subgroup to bond plexiglas tubes filled with a composite resin to the ceramic plate. The specimens were stored in water at 37°C for 3 days without thermal cycling, or for 30 or 150 days with 7500 or 37,500 thermal cycles between 5°C and 55°C, respectively. All specimens then underwent tensile bond strength testing. Initially, all bonding systems exhibited high TBS, but some showed a significant reduction after 30 and 150 days of storage. After 3, 30, and 150 days, Monobond Plus, which c...
Journal of the mechanical behavior of biomedical materials, Oct 1, 2017
The purpose of this in vitro study was to evaluate the influence of thermodynamic loading on the ... more The purpose of this in vitro study was to evaluate the influence of thermodynamic loading on the durability and fracture resistance behavior of occlusal veneers fabricated from different biomedical dental CAD/CAM materials. The occlusal surfaces of 64 extracted premolars were prepared in the enamel layer and restored with occlusal veneers with a fissure/cusp thickness of 0.5/0.8mm made from four different dental CAD/CAM materials: group LD lithium disilicate (e.max CAD), group LS zirconia-reinforced lithium silicate (Vita Suprinity), group PI polymer-infiltrated ceramic (Vita Enamic), and group PM polymethylmethacrylate PMMA (Telio CAD). The prepared teeth were etched with phosphoric acid. The occlusal veneers were then bonded using an adhesive luting system (Multilink Primer A/B and Multilink Automix luting resin). Half of the specimens were subjected to thermodynamic loading in a chewing simulator (1.2 million cycles at 98N). All specimens were quasi-statically loaded until fractu...
To evaluate the efficacy of different surface treatments on the repair of veneered zirconia ceram... more To evaluate the efficacy of different surface treatments on the repair of veneered zirconia ceramics. Forty-eight zirconia disks were divided into three groups according to the method of surface treatment: polished surface, air abraded, or ground using a special silicon carbide bur (SiC Grinding Bur). All specimens were primed using a primer containing MDP (Cimara Zircon, Voco) and then bonded to composite in Plexiglas tubes using dual-curing adhesive resin (Bifix QM, Voco). Each of the three groups was further divided into two subgroups (n = 8) stored either in water at 37°C for 3 days without thermocycling or stored in water at 37°C for 150 days with an additional 37,500 thermocycles between 5°C and 55°C. After storage, tensile bond strength (TBS) was measured in a universal testing machine. After 3 days of storage, silicon carbide bur and air-abraded groups showed high TBS that ranged from 32.7 to 41.0 MPa (p ≤ 0.05). After 150 days of storage with thermocycling, the air-abraded ...
The aim of this study was to test five types of implant restorations using titanium, zirconia and... more The aim of this study was to test five types of implant restorations using titanium, zirconia and lithium disilicate abutments after being subjected to long-term fatigue loading. Forty single-tooth implant restorations were assembled on titanium implants (FairTwo; FairImplant). The restorations differed only in the type of abutment used and were divided into five groups [Ti: titanium; Zr: zirconia with no metal base; ZrT: zirconia with titanium base; LaT: lithium disilicate abutment with titanium base; and LcT: lithium disilicate hybrid-abutment-crown with titanium base]. Specimens were subjected to dynamic load of 49 N up to 1,200,000 cycles using a dual-axis chewing simulator (Kausimulator; Willytech). The surviving specimens were subjected to quasi-static loading using a universal testing machine (Z010; Zwick) until the implant-abutment connection failed. The values of force (N) at which fracture or plastic deformation of the restoration occurred were calculated and the rate of d...
The whitish color of zirconia (ZrO2) abutments offers favorable esthetics compared with the grayi... more The whitish color of zirconia (ZrO2) abutments offers favorable esthetics compared with the grayish color of titanium (Ti) abutments. Nonetheless, ZrO2 has greater opacity, making it difficult to achieve natural tooth color. Therefore, lithium disilicate (LaT) abutments have been suggested to replace metal abutments. The purpose of this in vitro study was to evaluate the fracture strength and failure mode of single-tooth implant restorations using ZrO2 and LaT abutments, and to compare them with titanium (Ti) abutments. Five different types of abutments, Ti; ZrO2 with no metal base; ZrO2 with a metal base (ZrT); LaT; and LaT combination abutment and crown (LcT) were assembled on 40 Ti implants and restored with LaT crowns. Specimens were subjected to quasistatic loading using a universal testing machine, until the implant-abutment connection failed. As bending of the metal would be considered a clinical failure, the values of force (N) at which the plastic deformation of the metal occurred were calculated, and the rate of deformation was analyzed. Statistical analysis was done using the Mann-Whitney U test (α=.05). Group ZrO2 revealed the lowest resistance to failure with a mean of 202 ±33 N. Groups ZrT, LaT, and LaC withstood higher forces without fracture or debonding of the ceramic suprastructure, and failure was due to deformation of metal bases, with no statistically significant differences between these groups regarding the bending behavior. Within the limitations of this in vitro study, it was concluded that LaT abutments have the potential to withstand the physiological occlusal forces that occur in the anterior region and that ZrO2 abutments combined with Ti inserts have much higher fracture strength than pure ZrO2 abutments.
Dental materials : official publication of the Academy of Dental Materials, Dec 1, 2016
The aim of this laboratory study was to evaluate the horizontal and vertical effects of the polym... more The aim of this laboratory study was to evaluate the horizontal and vertical effects of the polymerization shrinkage of three-unit temporary fixed dental prostheses (FDPs) on the position of the prepared teeth. In addition, the reduction of these effects by using different fabrication techniques was evaluated. A total of 192 temporary FDPs were fabricated using one methacrylate (MA) and two dimethacrylate (DMA) materials. Each material group (n=64) was divided into two groups according to the fabrication methods (M1: curing on the prepared teeth, M2: curing in a silicone mold). Each fabrication group was divided into four subgroups (n=8) according to the relining method used (B: no relining, S: spacer foil 300μm, DG: grinding-out with 500μm cutting depth, and FG: free grinding). The experimental apparatus consisted of two abutment teeth lowered at right angles into a silicone mold. One prepared tooth was embedded in silicone to simulate the periodontium and permit slight horizontal ...
To test the bond strength and durability after artificial aging of so-called universal primers an... more To test the bond strength and durability after artificial aging of so-called universal primers and universal multimode adhesives to lithium disilicate or zirconia ceramics. A total of 240 ceramic plates, divided into two groups, were produced and conditioned: 120 acid-etched lithium disilicate plates (IPS e.max CAD) and 120 air-abraded zirconia plates (Zenostar T). Each group was divided into five subgroups (n = 24), and a universal restorative primer or multimode universal adhesive was used for each subgroup to bond plexiglas tubes filled with a composite resin to the ceramic plate. The specimens were stored in water at 37°C for 3 days without thermal cycling, or for 30 or 150 days with 7500 or 37,500 thermal cycles between 5°C and 55°C, respectively. All specimens then underwent tensile bond strength testing. Initially, all bonding systems exhibited high TBS, but some showed a significant reduction after 30 and 150 days of storage. After 3, 30, and 150 days, Monobond Plus, which c...
Journal of the mechanical behavior of biomedical materials, Oct 1, 2017
The purpose of this in vitro study was to evaluate the influence of thermodynamic loading on the ... more The purpose of this in vitro study was to evaluate the influence of thermodynamic loading on the durability and fracture resistance behavior of occlusal veneers fabricated from different biomedical dental CAD/CAM materials. The occlusal surfaces of 64 extracted premolars were prepared in the enamel layer and restored with occlusal veneers with a fissure/cusp thickness of 0.5/0.8mm made from four different dental CAD/CAM materials: group LD lithium disilicate (e.max CAD), group LS zirconia-reinforced lithium silicate (Vita Suprinity), group PI polymer-infiltrated ceramic (Vita Enamic), and group PM polymethylmethacrylate PMMA (Telio CAD). The prepared teeth were etched with phosphoric acid. The occlusal veneers were then bonded using an adhesive luting system (Multilink Primer A/B and Multilink Automix luting resin). Half of the specimens were subjected to thermodynamic loading in a chewing simulator (1.2 million cycles at 98N). All specimens were quasi-statically loaded until fractu...
To evaluate the efficacy of different surface treatments on the repair of veneered zirconia ceram... more To evaluate the efficacy of different surface treatments on the repair of veneered zirconia ceramics. Forty-eight zirconia disks were divided into three groups according to the method of surface treatment: polished surface, air abraded, or ground using a special silicon carbide bur (SiC Grinding Bur). All specimens were primed using a primer containing MDP (Cimara Zircon, Voco) and then bonded to composite in Plexiglas tubes using dual-curing adhesive resin (Bifix QM, Voco). Each of the three groups was further divided into two subgroups (n = 8) stored either in water at 37°C for 3 days without thermocycling or stored in water at 37°C for 150 days with an additional 37,500 thermocycles between 5°C and 55°C. After storage, tensile bond strength (TBS) was measured in a universal testing machine. After 3 days of storage, silicon carbide bur and air-abraded groups showed high TBS that ranged from 32.7 to 41.0 MPa (p ≤ 0.05). After 150 days of storage with thermocycling, the air-abraded ...
The aim of this study was to test five types of implant restorations using titanium, zirconia and... more The aim of this study was to test five types of implant restorations using titanium, zirconia and lithium disilicate abutments after being subjected to long-term fatigue loading. Forty single-tooth implant restorations were assembled on titanium implants (FairTwo; FairImplant). The restorations differed only in the type of abutment used and were divided into five groups [Ti: titanium; Zr: zirconia with no metal base; ZrT: zirconia with titanium base; LaT: lithium disilicate abutment with titanium base; and LcT: lithium disilicate hybrid-abutment-crown with titanium base]. Specimens were subjected to dynamic load of 49 N up to 1,200,000 cycles using a dual-axis chewing simulator (Kausimulator; Willytech). The surviving specimens were subjected to quasi-static loading using a universal testing machine (Z010; Zwick) until the implant-abutment connection failed. The values of force (N) at which fracture or plastic deformation of the restoration occurred were calculated and the rate of d...
The whitish color of zirconia (ZrO2) abutments offers favorable esthetics compared with the grayi... more The whitish color of zirconia (ZrO2) abutments offers favorable esthetics compared with the grayish color of titanium (Ti) abutments. Nonetheless, ZrO2 has greater opacity, making it difficult to achieve natural tooth color. Therefore, lithium disilicate (LaT) abutments have been suggested to replace metal abutments. The purpose of this in vitro study was to evaluate the fracture strength and failure mode of single-tooth implant restorations using ZrO2 and LaT abutments, and to compare them with titanium (Ti) abutments. Five different types of abutments, Ti; ZrO2 with no metal base; ZrO2 with a metal base (ZrT); LaT; and LaT combination abutment and crown (LcT) were assembled on 40 Ti implants and restored with LaT crowns. Specimens were subjected to quasistatic loading using a universal testing machine, until the implant-abutment connection failed. As bending of the metal would be considered a clinical failure, the values of force (N) at which the plastic deformation of the metal occurred were calculated, and the rate of deformation was analyzed. Statistical analysis was done using the Mann-Whitney U test (α=.05). Group ZrO2 revealed the lowest resistance to failure with a mean of 202 ±33 N. Groups ZrT, LaT, and LaC withstood higher forces without fracture or debonding of the ceramic suprastructure, and failure was due to deformation of metal bases, with no statistically significant differences between these groups regarding the bending behavior. Within the limitations of this in vitro study, it was concluded that LaT abutments have the potential to withstand the physiological occlusal forces that occur in the anterior region and that ZrO2 abutments combined with Ti inserts have much higher fracture strength than pure ZrO2 abutments.
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