Monomer priming of denture teeth and its effects on the bond strength of composite resin Leila Perea, DDS, MSc,a Jukka P. Matinlinna, MSc, PhD,b Mimmi Tolvanen, PhD,c Lippo V. Lassila, DDS,d and Pekka K. Vallittu, DDS, PhDe University of Turku, Turku, Finland; The University of Hong Kong, Hong Kong SAR, P.R. China Statement of problem. The bond strength of acrylic resin denture teeth used as pontics in fiber-reinforced composite fixed dental prostheses needs to be improved. Purpose. The purpose of this study was to assess the influence of various chemical surface-conditioning monomers on the ridge-lap surface of acrylic resin denture teeth by determining the strength of their bonding to a composite resin and changes in surface hardness. Material and methods. Acrylic resin denture teeth of 2 different brands (Artic 8 and Vitapan Cuspiform) (n¼120) were tested. Four monomer systems were used as surface primers (conditioning): a flowable composite resin, methylmethacrylate 99%, composite primer, and a photopolymerizable dimethacrylate resin. Five surface-conditioning exposure times were used: no conditioning, 1, 5, 15, and 60 minutes. Surface microhardness measurements were made after the application of the monomer systems. Shear bond strength tests were subsequently performed, followed by a new surface microhardness indentation after the application of the load. The evaluation of the changes on specimen surfaces was performed with a scanning electron microscope. The differences between the shear bond strength and the surface hardness were evaluated for statistical significance by using a 3-way ANOVA. Results. Tooth brand, monomer used, exposure time, and their 2- and 3-way interactions had a significant effect on the shear bond strength and hardness before and after testing, except for the 3-way interaction effect on hardness before testing. Conclusions. The chemical pretreatment of the ridge-lap surface of acrylic resin denture teeth increased the shear bond strength and influenced the surface hardness. The monomer systems caused dissolution on the denture surfaces. (J Prosthet Dent 2014;-:---)
Clinical Implications The higher shear bond strength of acrylic resin denture teeth used as pontics may increase the durability and clinical effectiveness of fiber-reinforced composites fixed dental prostheses. Acrylic resin denture teeth are used in prosthetic dentistry as components of removable and fixed dental
prostheses (FDP) because of their advantages over porcelain teeth. Such benefits include their prefabricated
shape and pleasing shade, adequate mechanical strength, easy occlusal adjustment, and high bond strength to
Presented at the European Prosthodontic Association and the Scandinavian Society for Prosthetic Dentistry annual meeting, Turku, Finland, August 2013. a
Doctoral student, Institute of Dentistry, Department of Biomaterials Science and Turku Clinical Biomaterials Centre, University of Turku. Associate Professor in Dental Materials Science, Faculty of Dentistry, Dental Materials Science, The University of Hong Kong. c Researcher and Statistician, Department of Community Dentistry, University of Turku. d Laboratory Head, Turku Clinical Biomaterials Centre, University of Turku. e Professor and Chair of Biomaterials Science, Director of Turku Clinical Biomaterials Centre, Institute of Dentistry, Department of Biomaterials Science and Turku Clinical Biomaterials Centre, University of Turku. b
Perea et al
2
Volume denture base materials.1,2 Acrylic resin teeth have mainly been used in the fabrication of complete dentures but also in implant dentistry, in which they often are used in implant-supported prostheses.3 In FDPs, acrylic resin denture teeth have recently been tested in inlay-retained fiber-reinforced composite FDPs to replace missing teeth.4 Debonding or the fracture of acrylic resin denture teeth from the denture base is a common clinical problem that implicates 22% to 30% of denture repairs.5,6 This often requires the replacement of the acrylic resin denture tooth or rebonding. Several investigators reported different clinical and technical methods of repairing acrylic resin denture teeth with a composite resin.7-10 Numerous retention systems have been introduced to improve the bond strength of acrylic resin denture teeth. Such systems include mechanical and chemical treatments. Some examples are grooving,11 grinding,12 high-energy abrasion, application of monomer, nonpolymerizable solvents, and even silanization.13-15 Although silanization16 seems unjustified because of the polymeric nature of denture teeth. Controversial findings have been reported regarding the changes produced in the ridge-lap surfaces of acrylic resin denture teeth after the implementation of mechanical treatments. Some studies claim that such treatments may not result in significantly increased bond strengths when
Table I.
compared with the unmodified tooth surface.17-19 By contrast, there also are reports that such treatments enhance the bond strength.20e22 The effectiveness of chemical bonding procedures also has been reported with inconclusive results. Based on the composition of the acrylic resin denture teeth, the use of monomers to soften or dissolve the tooth ridge-lap surface also has been suggested.17,23,24 Acrylic resin denture teeth are primarily composed of poly(methyl methacrylate) (PMMA) beads and color pigments in a cross-linked polymer matrix.1 Between the PMMA beads and the cross-linked polymer matrix, there is an intermediate layer called a semi-interpenetrating polymer network (IPN).25 The bonding mechanism of acrylic resin denture teeth to composite resin is based on the dissolution of the ridge-lap surface of the tooth by monomers and on the formation of secondary IPN bonding. During the formation of the secondary IPN, the polymer is dissolved by the solvent molecules of the monomer, which turns the polymer into a gel. Given this, the monomers penetrate the solvent-rich surfaces.26-28 The dissolution gradient varies, depending on how effectively the monomeric solvent swells and dissolves the PMMA, the contact, wetting time, temperature, and the polymeric structure of the substrate.13,22,29 The contribution of the secondary IPN bonding is essential when acrylic resin
-
Issue
-
denture teeth need to be bonded or repaired in the oral cavity or in the dental laboratory. The question of bonding denture teeth with photopolymerizable monomer systems is relevant if denture teeth are used more frequently as pontics in fiber-reinforced composite FDPs. Limited data have been reported regarding the most efficient type of monomeric solvent and the exposure time needed to generate a strong secondary IPN bonding between acrylic resin denture teeth and composite resins.30,31 The aim of this study was to compare the influence of various chemical surface-conditioning monomers on the ridge-lap surface of acrylic resin denture teeth by determining the bond strength to composite resin and changes in the surface hardness. The null hypothesis was that no variation would be noted in the bond strength between composite resin and acrylic resin denture teeth when different chemical surface-conditioning monomers were used.
MATERIAL AND METHODS The materials used are listed in Table I. The specimens were fabricated by using autopolymerizing acrylic resin (Palapress; Heraeus Kultzer GmbH) as a base material into which identical acrylic resin denture teeth of 2 different brands (Artic 8 [Heraeus Kultzer GmbH] and Vitapan Cuspiform [Vita])
Materials used
Brand
Manufacturer
Lot No.
Heraeus Kultzer
1211220981
PMMA, dimethacrylate
Vita
M6
PMMA, dimethacrylate
Heraeus Kultzer
012531
Methylmethacrylate, 99%
Sigma-Aldrich
S76535-139
MMA
Stick FLOW
StickTech-GC
5104628
Bis-GMA, TEGDMA
Artic 8 Vitapan Cuspiform Palapress
Composite primer
Composition
Powder: PMMA-copolymer; liquid: MMA, dimethacrylate, butanediol dimethacrylate, alkoxylated polyols tetraacrylate, additives
GC
1208012
Monofunctional methacrylate, UDMA, camphorquinone
Stick RESIN
StickTech-GC
5107797
Bis-GMA, TEGDMA
Tetrahydrofuran
Sigma-Aldrich
40750
Tetrahydrofuran
PMMA, polymethylmethacrylate; MMA, methylmethacrylate; Bis-GMA, bisphenol A-glycidyl dimethacrylate; TEGDMA, triethylene glycol dimethacrylate; UDMA, urethane dimethacrylate
The Journal of Prosthetic Dentistry
Perea et al
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2014
3
were bonded. An equal amount of material was removed from the ridgelap surfaces of the denture teeth. They were wet ground flat with 1200 grit (FEPA) silicon carbide grinding paper to establish a uniformly flat bonding surface. Next, the substrates were cleansed in deionized water in an ultrasonic cleaning device (Quantrex 90; L&R Ultrasonics) for 10 minutes and allowed to dry under ambient laboratory conditions (23 C 1 C) for 60 minutes. Four monomer systems were used as surface conditioners to pretreat the surfaces of the denture teeth: flowable composite resin (Stick FLOW; StickTech-GC), methylmethacrylate 99% (Sigma-Aldrich), composite primer (GC), and Stick Resin (StickTech Ltd). A total of 120 specimens were randomly divided into 2 groups according to the brand, 60 of Artic 8 and 60 of Vitapan Cuspiform. In each group, the specimens were randomly divided into 4 subgroups (n¼15) according to the surface-conditioning monomer used. Each subgroup was subdivided into 5 surface-conditioning exposure times: no pretreatment (control), 1, 5, 15, and 60 minutes. In each subgroup, 1 of the 4 monomers previously described was used as a surface conditioner. The first subgroup of each group was not pretreated, in accordance with the 5 exposure times described previously. Then, surface microhardness testing
was performed on selected portions of the acrylic resin denture teeth with a Vickers hardness testing machine (Duramin-5; Struers). The force used was 245.2 mN for 15 seconds. One randomly selected indentation was made on each specimen to obtain the surface microhardness value. Thereafter, a flowable composite resin (Stick FLOW) was applied in 1-mm increments to the substrate surface with a translucent polyethylene mold, with a diameter of 3.6 mm and height of 4 mm. Each specimen was then photopolymerized with a hand-held lightpolymerizing unit (Elipar S10; 3M ESPE) for 40 seconds. After the photopolymerization process, the specimens were stored in dry conditions for 24 hours at room temperature (23 C 1 C). Shear bond testing was performed with a universal testing machine (Model LR 30K plus; Lloyd Instruments), and data were recorded with data analysis software (Nexygen; Lloyd Instruments). The specimens were loaded at the interface of the substrate and the flowable composite resin at a 1.0 mm/min crosshead speed until fracture occurred. Shear bond strengths were calculated in MPa. After the shear bond test, surface microhardness testing was immediately performed on the surfaces of the acrylic resin denture teeth. This was done to measure the eventual changes in the surface microhardness
values after the specimen surfaces had photopolymerized. Subsequently, the 4 surface-conditioning monomers were used in the specimens selected for the second exposure time (1 minute), third (5 minutes), fourth (15 minutes), and fifth (60 minutes). In each subgroup, the unpolymerized monomer was allowed to contact the surfaces of the acrylic resin denture teeth and protected from light for the corresponding exposure time. After this time, any unpolymerized monomer was manually removed from the surface with a clean, dry paper tissue. In the groups in which composite primer and Stick Resin were used as surface-conditioning monomers, the next step involved the application of 1 layer of the corresponding monomer on the surfaces of the acrylic resin denture teeth. This layer was immediately photopolymerized for 20 seconds. In all groups, the flowable composite resin was then applied by using the mold described previously and was photopolymerized for 40 seconds in 2 directions. The specimens were stored dry for 24 hours at room temperature (23 C 1 C). Afterwards, shear bond strength testing was performed on each specimen, followed by surface microhardness testing. The fracture surfaces of the specimens were examined visually to determine the fracture type. After the last surface microhardness testing was made, the
Table II. Shear bond strength in MPa for chemical surface-conditioning components and exposure times in Artic 8 and Vitapan group Exposure Time, min Group
Monomer
0
1
5
15
Artic 8
Stick FLOW
1.05 (0.23)
1.24 (0.26)
1.73 (0.16)
1.75 (0.43)
1.72 (0.26)
Methylmethacrylate
1.26 (0.38)
0.94 (0.34)
1.04 (0.24)
0.67 (0.16)
1.27 (0.32)
Composite primer
6.09 (1.99)
9.08 (1.35)
7.96 (1.35)
6.59 (1.43)
5.40 (1.70)
Stick Resin
7.70 (2.81)
6.65 (2.05)
7.29 (1.76)
6.96 (0.71)
5.21 (0.36)
Stick FLOW
0.47 (0.10)
1.38 (0.16)
0.58 (0.24)
2.56 (0.93)
2.73 (0.70)
Methylmethacrylate
0.54 (0.36)
0.75 (0.25)
0.96 (0.27)
1.42 (0.58)
1.79 (1.21)
Composite primer
1.78 (0.61)
2.81 (0.84)
1.96 (0.72)
4.45 (1.49)
3.77 (1.12)
Stick Resin
2.34 (1.55)
3.41 (0.98)
2.71 (0.78)
7.98 (0.22)
6.19 (1.27)
Vitapan
Values are presented as mean (SD).
Perea et al
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4
Volume
-
Issue
-
Surface hardness in VHN for chemical surface-conditioning components and exposure time in Artic 8 and Vitapan group
Table III.
Exposure Time, min
Group
Monomer
Testing Period
Artic 8
Stick FLOW
B
23.3 (1.2)
20.9 (0.7)
19.8 (0.3)
19.3 (0.2)
18.3 (0.9)
A
22.8 (0.2)
22.4 (1.2)
21.5 (1.2)
22.3 (1.9)
22.8 (0.7)
Methylmethacrylate Composite primer Stick Resin
Vitapan
Stick FLOW Methylmethacrylate Composite primer Stick Resin
0
1
5
15
60
B
23.8 (1.5)
22.3 (0.5)
20.2 (0.7)
19.9 (0.7)
19.0 (0.9)
A
22.9 (1.7)
23.1 (2.0)
22.6 (0.7)
23.5 (0.1)
22.8 (1.7)
B
22.6 (0.4)
22.0 (0.8)
20.3 (0.9)
20.9 (0.3)
19.1 (1.4)
A
24.0 (1.7)
22.1 (1.1)
22.8 (1.0)
23.3 (1.1)
22.2 (0.9)
B
22.9 (1.4)
21.4 (1.9)
19.4 (1.1)
18.6 (0.9)
17.3 (1.3)
A
24.4 (1.8)
23.7 (0.6)
23.7 (1.4)
22.3 (1.2)
24.3 (1.1)
B
21.3 (0.6)
20.2 (0.3)
19.4 (1.0)
20.1 (0.4)
19.6 (0.3)
A
20.2 (0.9)
22.7 (1.3)
23.2 (1.1)
24.7 (0.2)
21.8 (0.5)
B
19.6 (0.6)
19.5 (0.6)
18.4 (0.6)
19.9 (0.8)
19.2 (0.6)
A
20.4 (0.8)
21.6 (0.5)
22.6 (1.1)
24.9 (0.6)
20.8 (0.6)
B
18.7 (0.4)
18.5 (0.4)
19.9 (0.2)
20.2 (0.2)
17.6 (0.4)
A
21.8 (0.9)
21.4 (0.5)
22.7 (0.7)
24.4 (0.5)
21.0 (0.5)
B
20.1 (0.9)
18.6 (0.5)
20.1 (0.4)
20.0 (0.9)
18.7 (0.5)
A
22.1 (0.7)
22.2 (0.8)
23.2 (0.6)
33.1 (1.7)
23.4 (0.4)
B, after application of component and before shear bond test; A, after shear bond test. Values are presented as mean (SD).
P values from 3-way ANOVA for effects of tooth brand, surface-conditioning component, exposure time, and their interactions on shear bond strength and surface hardness before and after shear bond testing
Table IV.
Shear Bond Strength
Hardness Before Testing
Tooth brand (Artic 8, Vitapan)
Clinical Implications The higher shear bond strength of acrylic resin denture teeth used as pontics may increase the durability and clinical effectiveness of fiber-reinforced composites fixed dental prostheses. Acrylic resin denture teeth are used in prosthetic dentistry as components of removable and fixed dental
prostheses (FDP) because of their advantages over porcelain teeth. Such benefits include their prefabricated
shape and pleasing shade, adequate mechanical strength, easy occlusal adjustment, and high bond strength to
Presented at the European Prosthodontic Association and the Scandinavian Society for Prosthetic Dentistry annual meeting, Turku, Finland, August 2013. a
Doctoral student, Institute of Dentistry, Department of Biomaterials Science and Turku Clinical Biomaterials Centre, University of Turku. Associate Professor in Dental Materials Science, Faculty of Dentistry, Dental Materials Science, The University of Hong Kong. c Researcher and Statistician, Department of Community Dentistry, University of Turku. d Laboratory Head, Turku Clinical Biomaterials Centre, University of Turku. e Professor and Chair of Biomaterials Science, Director of Turku Clinical Biomaterials Centre, Institute of Dentistry, Department of Biomaterials Science and Turku Clinical Biomaterials Centre, University of Turku. b
Perea et al
2
Volume denture base materials.1,2 Acrylic resin teeth have mainly been used in the fabrication of complete dentures but also in implant dentistry, in which they often are used in implant-supported prostheses.3 In FDPs, acrylic resin denture teeth have recently been tested in inlay-retained fiber-reinforced composite FDPs to replace missing teeth.4 Debonding or the fracture of acrylic resin denture teeth from the denture base is a common clinical problem that implicates 22% to 30% of denture repairs.5,6 This often requires the replacement of the acrylic resin denture tooth or rebonding. Several investigators reported different clinical and technical methods of repairing acrylic resin denture teeth with a composite resin.7-10 Numerous retention systems have been introduced to improve the bond strength of acrylic resin denture teeth. Such systems include mechanical and chemical treatments. Some examples are grooving,11 grinding,12 high-energy abrasion, application of monomer, nonpolymerizable solvents, and even silanization.13-15 Although silanization16 seems unjustified because of the polymeric nature of denture teeth. Controversial findings have been reported regarding the changes produced in the ridge-lap surfaces of acrylic resin denture teeth after the implementation of mechanical treatments. Some studies claim that such treatments may not result in significantly increased bond strengths when
Table I.
compared with the unmodified tooth surface.17-19 By contrast, there also are reports that such treatments enhance the bond strength.20e22 The effectiveness of chemical bonding procedures also has been reported with inconclusive results. Based on the composition of the acrylic resin denture teeth, the use of monomers to soften or dissolve the tooth ridge-lap surface also has been suggested.17,23,24 Acrylic resin denture teeth are primarily composed of poly(methyl methacrylate) (PMMA) beads and color pigments in a cross-linked polymer matrix.1 Between the PMMA beads and the cross-linked polymer matrix, there is an intermediate layer called a semi-interpenetrating polymer network (IPN).25 The bonding mechanism of acrylic resin denture teeth to composite resin is based on the dissolution of the ridge-lap surface of the tooth by monomers and on the formation of secondary IPN bonding. During the formation of the secondary IPN, the polymer is dissolved by the solvent molecules of the monomer, which turns the polymer into a gel. Given this, the monomers penetrate the solvent-rich surfaces.26-28 The dissolution gradient varies, depending on how effectively the monomeric solvent swells and dissolves the PMMA, the contact, wetting time, temperature, and the polymeric structure of the substrate.13,22,29 The contribution of the secondary IPN bonding is essential when acrylic resin
-
Issue
-
denture teeth need to be bonded or repaired in the oral cavity or in the dental laboratory. The question of bonding denture teeth with photopolymerizable monomer systems is relevant if denture teeth are used more frequently as pontics in fiber-reinforced composite FDPs. Limited data have been reported regarding the most efficient type of monomeric solvent and the exposure time needed to generate a strong secondary IPN bonding between acrylic resin denture teeth and composite resins.30,31 The aim of this study was to compare the influence of various chemical surface-conditioning monomers on the ridge-lap surface of acrylic resin denture teeth by determining the bond strength to composite resin and changes in the surface hardness. The null hypothesis was that no variation would be noted in the bond strength between composite resin and acrylic resin denture teeth when different chemical surface-conditioning monomers were used.
MATERIAL AND METHODS The materials used are listed in Table I. The specimens were fabricated by using autopolymerizing acrylic resin (Palapress; Heraeus Kultzer GmbH) as a base material into which identical acrylic resin denture teeth of 2 different brands (Artic 8 [Heraeus Kultzer GmbH] and Vitapan Cuspiform [Vita])
Materials used
Brand
Manufacturer
Lot No.
Heraeus Kultzer
1211220981
PMMA, dimethacrylate
Vita
M6
PMMA, dimethacrylate
Heraeus Kultzer
012531
Methylmethacrylate, 99%
Sigma-Aldrich
S76535-139
MMA
Stick FLOW
StickTech-GC
5104628
Bis-GMA, TEGDMA
Artic 8 Vitapan Cuspiform Palapress
Composite primer
Composition
Powder: PMMA-copolymer; liquid: MMA, dimethacrylate, butanediol dimethacrylate, alkoxylated polyols tetraacrylate, additives
GC
1208012
Monofunctional methacrylate, UDMA, camphorquinone
Stick RESIN
StickTech-GC
5107797
Bis-GMA, TEGDMA
Tetrahydrofuran
Sigma-Aldrich
40750
Tetrahydrofuran
PMMA, polymethylmethacrylate; MMA, methylmethacrylate; Bis-GMA, bisphenol A-glycidyl dimethacrylate; TEGDMA, triethylene glycol dimethacrylate; UDMA, urethane dimethacrylate
The Journal of Prosthetic Dentistry
Perea et al
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2014
3
were bonded. An equal amount of material was removed from the ridgelap surfaces of the denture teeth. They were wet ground flat with 1200 grit (FEPA) silicon carbide grinding paper to establish a uniformly flat bonding surface. Next, the substrates were cleansed in deionized water in an ultrasonic cleaning device (Quantrex 90; L&R Ultrasonics) for 10 minutes and allowed to dry under ambient laboratory conditions (23 C 1 C) for 60 minutes. Four monomer systems were used as surface conditioners to pretreat the surfaces of the denture teeth: flowable composite resin (Stick FLOW; StickTech-GC), methylmethacrylate 99% (Sigma-Aldrich), composite primer (GC), and Stick Resin (StickTech Ltd). A total of 120 specimens were randomly divided into 2 groups according to the brand, 60 of Artic 8 and 60 of Vitapan Cuspiform. In each group, the specimens were randomly divided into 4 subgroups (n¼15) according to the surface-conditioning monomer used. Each subgroup was subdivided into 5 surface-conditioning exposure times: no pretreatment (control), 1, 5, 15, and 60 minutes. In each subgroup, 1 of the 4 monomers previously described was used as a surface conditioner. The first subgroup of each group was not pretreated, in accordance with the 5 exposure times described previously. Then, surface microhardness testing
was performed on selected portions of the acrylic resin denture teeth with a Vickers hardness testing machine (Duramin-5; Struers). The force used was 245.2 mN for 15 seconds. One randomly selected indentation was made on each specimen to obtain the surface microhardness value. Thereafter, a flowable composite resin (Stick FLOW) was applied in 1-mm increments to the substrate surface with a translucent polyethylene mold, with a diameter of 3.6 mm and height of 4 mm. Each specimen was then photopolymerized with a hand-held lightpolymerizing unit (Elipar S10; 3M ESPE) for 40 seconds. After the photopolymerization process, the specimens were stored in dry conditions for 24 hours at room temperature (23 C 1 C). Shear bond testing was performed with a universal testing machine (Model LR 30K plus; Lloyd Instruments), and data were recorded with data analysis software (Nexygen; Lloyd Instruments). The specimens were loaded at the interface of the substrate and the flowable composite resin at a 1.0 mm/min crosshead speed until fracture occurred. Shear bond strengths were calculated in MPa. After the shear bond test, surface microhardness testing was immediately performed on the surfaces of the acrylic resin denture teeth. This was done to measure the eventual changes in the surface microhardness
values after the specimen surfaces had photopolymerized. Subsequently, the 4 surface-conditioning monomers were used in the specimens selected for the second exposure time (1 minute), third (5 minutes), fourth (15 minutes), and fifth (60 minutes). In each subgroup, the unpolymerized monomer was allowed to contact the surfaces of the acrylic resin denture teeth and protected from light for the corresponding exposure time. After this time, any unpolymerized monomer was manually removed from the surface with a clean, dry paper tissue. In the groups in which composite primer and Stick Resin were used as surface-conditioning monomers, the next step involved the application of 1 layer of the corresponding monomer on the surfaces of the acrylic resin denture teeth. This layer was immediately photopolymerized for 20 seconds. In all groups, the flowable composite resin was then applied by using the mold described previously and was photopolymerized for 40 seconds in 2 directions. The specimens were stored dry for 24 hours at room temperature (23 C 1 C). Afterwards, shear bond strength testing was performed on each specimen, followed by surface microhardness testing. The fracture surfaces of the specimens were examined visually to determine the fracture type. After the last surface microhardness testing was made, the
Table II. Shear bond strength in MPa for chemical surface-conditioning components and exposure times in Artic 8 and Vitapan group Exposure Time, min Group
Monomer
0
1
5
15
Artic 8
Stick FLOW
1.05 (0.23)
1.24 (0.26)
1.73 (0.16)
1.75 (0.43)
1.72 (0.26)
Methylmethacrylate
1.26 (0.38)
0.94 (0.34)
1.04 (0.24)
0.67 (0.16)
1.27 (0.32)
Composite primer
6.09 (1.99)
9.08 (1.35)
7.96 (1.35)
6.59 (1.43)
5.40 (1.70)
Stick Resin
7.70 (2.81)
6.65 (2.05)
7.29 (1.76)
6.96 (0.71)
5.21 (0.36)
Stick FLOW
0.47 (0.10)
1.38 (0.16)
0.58 (0.24)
2.56 (0.93)
2.73 (0.70)
Methylmethacrylate
0.54 (0.36)
0.75 (0.25)
0.96 (0.27)
1.42 (0.58)
1.79 (1.21)
Composite primer
1.78 (0.61)
2.81 (0.84)
1.96 (0.72)
4.45 (1.49)
3.77 (1.12)
Stick Resin
2.34 (1.55)
3.41 (0.98)
2.71 (0.78)
7.98 (0.22)
6.19 (1.27)
Vitapan
Values are presented as mean (SD).
Perea et al
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Volume
-
Issue
-
Surface hardness in VHN for chemical surface-conditioning components and exposure time in Artic 8 and Vitapan group
Table III.
Exposure Time, min
Group
Monomer
Testing Period
Artic 8
Stick FLOW
B
23.3 (1.2)
20.9 (0.7)
19.8 (0.3)
19.3 (0.2)
18.3 (0.9)
A
22.8 (0.2)
22.4 (1.2)
21.5 (1.2)
22.3 (1.9)
22.8 (0.7)
Methylmethacrylate Composite primer Stick Resin
Vitapan
Stick FLOW Methylmethacrylate Composite primer Stick Resin
0
1
5
15
60
B
23.8 (1.5)
22.3 (0.5)
20.2 (0.7)
19.9 (0.7)
19.0 (0.9)
A
22.9 (1.7)
23.1 (2.0)
22.6 (0.7)
23.5 (0.1)
22.8 (1.7)
B
22.6 (0.4)
22.0 (0.8)
20.3 (0.9)
20.9 (0.3)
19.1 (1.4)
A
24.0 (1.7)
22.1 (1.1)
22.8 (1.0)
23.3 (1.1)
22.2 (0.9)
B
22.9 (1.4)
21.4 (1.9)
19.4 (1.1)
18.6 (0.9)
17.3 (1.3)
A
24.4 (1.8)
23.7 (0.6)
23.7 (1.4)
22.3 (1.2)
24.3 (1.1)
B
21.3 (0.6)
20.2 (0.3)
19.4 (1.0)
20.1 (0.4)
19.6 (0.3)
A
20.2 (0.9)
22.7 (1.3)
23.2 (1.1)
24.7 (0.2)
21.8 (0.5)
B
19.6 (0.6)
19.5 (0.6)
18.4 (0.6)
19.9 (0.8)
19.2 (0.6)
A
20.4 (0.8)
21.6 (0.5)
22.6 (1.1)
24.9 (0.6)
20.8 (0.6)
B
18.7 (0.4)
18.5 (0.4)
19.9 (0.2)
20.2 (0.2)
17.6 (0.4)
A
21.8 (0.9)
21.4 (0.5)
22.7 (0.7)
24.4 (0.5)
21.0 (0.5)
B
20.1 (0.9)
18.6 (0.5)
20.1 (0.4)
20.0 (0.9)
18.7 (0.5)
A
22.1 (0.7)
22.2 (0.8)
23.2 (0.6)
33.1 (1.7)
23.4 (0.4)
B, after application of component and before shear bond test; A, after shear bond test. Values are presented as mean (SD).
P values from 3-way ANOVA for effects of tooth brand, surface-conditioning component, exposure time, and their interactions on shear bond strength and surface hardness before and after shear bond testing
Table IV.
Shear Bond Strength
Hardness Before Testing
Tooth brand (Artic 8, Vitapan)
