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1.
Effect on push-out bond strength of glass-fiber posts functionalized with polydopamine using different adhesives.
Chen, Q, Cai, Q, Li, Y, Wei, XY, Huang, Z, Wang, XZ
The journal of adhesive dentistry. 2014;(2):177-84
Abstract
PURPOSE To evaluate the push-out bond strengths of prefabricated glass-fiber posts (Beijing Oya Biomaterials) with polydopamine functionalized to root dentin using two different resin cements (Paracore and RelyX Unicem) in different root regions (cervical, middle, and apical). MATERIALS AND METHODS Forty extracted human, single-rooted teeth were endodontically treated and a 9-mm post space was prepared in each tooth with post drills provided by the manufacturer. Specimens were then randomly assigned into four groups (n = 10 per group), depending on the adhesive system and post surface treatment used: group IA (Paracore + polydopamine); group IB (Paracore + control); group IIA (RelyX Unicem + polydopamine); group IIB (RelyX Unicem + control). Following post cementation, the specimens were stored in distilled water at 37°C for 7 days. The push-out test was performed using a universal testing machine (0.5 mm/ min), and the failure modes were examined with a stereomicroscope. Data were statistically analyzed using twoway ANOVA (p = 0.05). RESULTS Bond strengths (mean ± SD) were: 7.909 ± 3.166 MPa (group IA), 4.675 ± 2.170 MPa (group IB), 8.186 ± 2.766 MPa (group IIA), 4.723 ± 2.084 MPa (group IIB). The bond strength of polydopamine groups was significantly higher than one of the control groups (p < 0.0001). No significant difference was found in the micro push-out bond strengths between the two resin cement groups or the root regions (p > 0.05). Stereomicroscopic analysis showed a higher percentage of adhesive than cohesive failures in all groups. CONCLUSION Surface polydopamine functionalization was confirmed to be a reliable method for improving the bond strength of resin luting agents to fiber posts. The bond strength of Paracore to fiber posts was not significantly different from that of RelyX Unicem, and considering its convenient application, Paracore can be recommended.
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2.
Effect of surface treatments of zirconia ceramics on the bond strength to resin cement.
Cheung, GC, Botelho, MG, Matinlinna, JP
The journal of adhesive dentistry. 2014;(1):49-56
Abstract
PURPOSE The purpose of this in vitro study was to evaluate the bond strength of a resin luting cement to zirconia surfaces that had received two novel surface pretreatment methods: etching of a pre-fired overglaze or paste liner on the zirconia substrate. MATERIALS AND METHODS Fully sintered zirconia disks were assigned to 6 groups according to the surface pretreatment: firing of 2 layers of paste liner which was then etched with hydrofluoric acid and treated with silane (Liner group); firing of 2 layers of overglaze which were then etched with hydrofluoric acid and treated with silane (glaze group); Rocatec treatment and silane application (Rocatec group); Rocatec treatment followed by ultrasonic cleaning and silanization (ultrasonic-Rocatec group); sandblasted with alumina (alumina group); as-sintered with no pretreatment (control group). Twenty composite resin cylinders were bonded to each group with Panavia F 2.0. Each group was further divided into 2 subgroups (n = 10) for 2 different storage conditions: 24 h water storage or 3 weeks water storage plus 6000 thermocycles between 5°C and 55°C. The shear bond strength was then determined. Statistical analyses with two-way ANOVA were conducted; the level of significance was set at p < 0.05. RESULTS At 24 h, the shear bond strength values of all groups except the control showed no statistically significant difference. After artificial aging, the mean bond strength of all groups dropped, but the decrease in the glaze group was not statistically significant. The glaze group showed the highest shear bond strength. However, that was not statistically different from the liner or the Rocatec group without ultrasonic cleaning (p < 0.05). All the control specimens debonded spontaneously after aging. Ultrasonic cleaning after Rocatec treatment caused a reduction in shear bond strength, but the difference was not statistically significant. CONCLUSION Both the fired paste liner and overglazed ceramic treated zirconia surfaces provided a strong and durable bond to resin cement under the conditions tested.
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3.
Effects of surface treatments, thermocycling, and cyclic loading on the bond strength of a resin cement bonded to a lithium disilicate glass ceramic.
Guarda, GB, Correr, AB, Gonçalves, LS, Costa, AR, Borges, GA, Sinhoreti, MA, Correr-Sobrinho, L
Operative dentistry. 2013;(2):208-17
Abstract
SUMMARY Objectives : The aim of this present study was to investigate the effect of two surface treatments, fatigue and thermocycling, on the microtensile bond strength of a newly introduced lithium disilicate glass ceramic (IPS e.max Press, Ivoclar Vivadent) and a dual-cured resin cement. Methods : A total of 18 ceramic blocks (10 mm long × 7 mm wide × 3.0 mm thick) were fabricated and divided into six groups (n=3): groups 1, 2, and 3-air particle abraded for five seconds with 50-μm aluminum oxide particles; groups 4, 5, and 6-acid etched with 10% hydrofluoric acid for 20 seconds. A silane coupling agent was applied onto all specimens and allowed to dry for five seconds, and the ceramic blocks were bonded to a block of composite Tetric N-Ceram (Ivoclar Vivadent) with RelyX ARC (3M ESPE) resin cement and placed under a 500-g static load for two minutes. The cement excess was removed with a disposable microbrush, and four periods of light activation for 40 seconds each were performed at right angles using an LED curing unit (UltraLume LED 5, Ultradent) with a final 40 second light exposure from the top surface. All of the specimens were stored in distilled water at 37°C for 24 hours. Groups 2 and 5 were submitted to 3,000 thermal cycles between 5°C and 55°C, and groups 3 and 6 were submitted to a fatigue test of 100,000 cycles at 2 Hz. Specimens were sectioned perpendicular to the bonding area to obtain beams with a cross-sectional area of 1 mm(2) (30 beams per group) and submitted to a microtensile bond strength test in a testing machine (EZ Test) at a crosshead speed of 0.5 mm/min. Data were submitted to analysis of variance and Tukey post hoc test (p≤0.05). Results : The microtensile bond strength values (MPa) were 26.9 ± 6.9, 22.2 ± 7.8, and 21.2 ± 9.1 for groups 1-3 and 35.0 ± 9.6, 24.3 ± 8.9, and 23.9 ± 6.3 for groups 4-6. For the control group, fatigue testing and thermocycling produced a predominance of adhesive failures. Fatigue and thermocycling significantly decreased the microtensile bond strength for both ceramic surface treatments when compared with the control groups. Etching with 10% hydrofluoric acid significantly increased the microtensile bond strength for the control group.
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4.
Testing rate and cementation seating load effects on resin-strengthening of a dental porcelain analogue.
Hooi, P, Addison, O, Fleming, GJ
Journal of dentistry. 2013;(6):514-20
Abstract
OBJECTIVES To determine the resin-strengthening dependence of a soda-lime-glass analogue for dental porcelain as a function of biaxial flexure strength (BFS), test crosshead rate and cementation seating load. METHODS Disc-shaped soda-lime glass specimens were divided into twelve groups (n=24), alumina particle air abraded and hydrofluoric acid-etched. Specimens (Groups A-D) were stored in a desiccator prior to testing at crosshead rates of 0.01, 0.1, 1 and 10mm/min, respectively. The remaining specimens were silane treated, Rely-X Veneer resin-coated with a seating load of 5N (Groups E-H) and 30N (Groups I-L) prior to light irradiation at 480±20mW/cm(2), 24h dry storage and BFS testing at 0.01, 0.1, 1 and 10mm/min, respectively. A linear logarithmic regression curve was fit to the raw data to elucidate static fatigue effects of the soda-lime-glass. Analysis of group means was performed utilising a general linear model univariate analysis and post hoc all paired Tukey tests (P<0.05). RESULTS The linear logarithmic regression curve demonstrated the static fatigue effects of the soda-lime-glass analogue. Rely-X Veneer resin-coating (Groups E-L) resulted in significant increases in the mean BFS data for all crosshead rates examined (all P<0.001). However, the pattern of rate dependence effects on resin-cementation deviated from the log relationship observed with the uncoated controls. CONCLUSION This study further highlights that when slow crack growth is simulated during testing, valuable insights into the significant modification of a hereto well described phenomenon such as resin-strengthening mediated by the resin-ceramic hybrid layer is provided.
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5.
Bond strength of different resin cement and ceramic shades bonded to dentin.
Passos, SP, Kimpara, ET, Bottino, MA, Júnior, GC, Rizkalla, AS
The journal of adhesive dentistry. 2013;(5):461-6
Abstract
PURPOSE To evaluate the microtensile bond strength (MTBS) of ceramic cemented to dentin varying the resin cement and ceramic shades. MATERIALS AND METHODS Two VITA VM7 ceramic shades (Base Dentine 0M1 and Base Dentine 5M3) were used. A spectrophotometer was used to determine the percentage translucency of ceramic (thickness: 2.5 mm). For the MTBS test, 80 molar dentin surfaces were etched and an adhesive was applied. Forty blocks (7.2 x 7.2 x 2.5 mm) of each ceramic shade were produced and the ceramic surface was etched (10% hydrofluoric acid) for 60 s, followed by the application of silane and resin cement (A3 yellow and transparent). The blocks were cemented to dentin using either A3 or transparent cement. Specimens were photoactivated for 20 s or 40 s, stored in distilled water (37°C/24 h), and sectioned. Eight experimental groups were obtained (n = 10). Specimens were tested for MTSB using a universal testing machine. Data were statistically analyzed using ANOVA and Tukey's post-hoc tests (α <= 0.05). RESULTS The percentage translucency of 0M1 and 5M3 ceramics were 10.06 (± 0.25)% and 1.34 (± 0.02)%, respectively. The lowest MTBS was observed for the ceramic shade 5M3. For the 0M1 ceramic, the A3 yellow cement that was photocured for 20 s exhibited the lowest MTBS, while the transparent cement that was photocured for 40 s presented the highest MTBS. CONCLUSIONS For the 2.5-mm-thick 5M3 ceramic restorations, the MTBS of ceramic cemented to dentin significantly increased. The dual-curing cement Variolink II photocured for 40 s is not recommended for cementing the Base Dentine 5M3 feldspathic ceramic to dentin.
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6.
Effect of polyacrylic acid on the interface and bond strength of self-adhesive resin cements to dentin.
Stona, P, Borges, GA, Montes, MA, Júnior, LH, Weber, JB, Spohr, AM
The journal of adhesive dentistry. 2013;(3):221-7
Abstract
PURPOSE To examine the influence of 11.5% polyacrylic acid pretreatment on the interface and bond strength of self-adhesive resin cements (Maxcem Elite, RelyX Unicem, SeT) to dentin. MATERIALS AND METHODS Fifty-six third molars were randomly divided into seven groups: RelyX ARC as control (ARC), RelyX Unicem (RLXU), Maxcem Elite (MCE), SeT (ST), polyacrylic acid+RelyX Unicem (RLXU-P), polyacrylic acid+Maxcem Elite (MCE-P), and polyacrylic acid+SeT (ST-P). Resin composite blocks were luted to flat dentin. After storage in distilled water for 24 h, sticks with a cross-sectional area of ca 0.80 mm2 were obtained (n = 24 per group) and submitted to a microtensile bond strength (µTBS) test in a universal testing machine at a crosshead speed of 0.5 mm/min. Two sets from each group were sectioned mesiodistally in the center of the crown and observed with a scanning electron microscope at 4000X magnification. RESULTS The mean results of the µTBS test (MPa) followed by the same letter do not differ statistically significantly according to ANOVA and Tukey's post-hoc test (p < 0.05): ARC = 24.19 (± 6.90)a, RLXU-P = 23.12 (± 6.18)a, MCE-P = 13.09 (± 5.87)b, RLXU = 10.23 (± 2.88)b,c, and MCE = 8.14 (± 4.63)c. All SeT specimens failed during the cutting procedure. The hybrid layer was not observed for the self-adhesive resin cements, and resin tags were observed for RelyX Unicem and Maxem Elite when dentin was pretreated with polyacrylic acid. CONCLUSION Pretreatment with 11.5% polyacrylic acid was effective for bonding RelyX Unicem and Maxcem Elite to dentin.
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7.
Can a soda-lime glass be used to demonstrate how patterns of strength dependence are influenced by pre-cementation and resin-cementation variables?
Hooi, P, Addison, O, Fleming, GJ
Journal of dentistry. 2013;(1):24-30
Abstract
OBJECTIVES To determine how the variability in biaxial flexure strength of a soda-lime glass analogue for a PLV and DBC material was influenced by precementation operative variables and following resin-cement coating. METHODS The flexural modulus of a transparent soda-lime glass was determined by longitudinally sectioning into rectangular bar-shaped specimens and the flexural moduli of three resin-based materials (Venus Flow, Rely-X Veneer and Clearfil Majesty Posterior) was also determined. Disc shaped soda-lime glass specimens (n=240) were divided into ten groups and were alumina particle air abraded, hydrofluoric (HF) acid-etched and resin-cement coated prior to biaxial flexure strength testing. Sample sets were profilometrically evaluated to determine the surface texture. One-way analyses of variance (ANOVA) and post hoc all paired Tukey tests were performed at a significance level of P<0.05. The mean biaxial flexure strengths were plotted against resin-coating thickness and a regression analysis enabled estimation of the 'actual' magnitude of strengthening. RESULTS The mean three-point flexural modulus of the soda-lime glass was 40.0 (1.0)GPa and the Venus Flow, Rely-X Veneer and Clearfil Majesty Posterior were 3.0 (0.2)GPa, 6.0 (0.2)GPa and 14.8 (1.6)GPa, respectively. At a theoretical 'zero' resin-coating thickness an increase in biaxial flexure strength of 20.1% (63.2MPa), 30.8% (68.8MPa) and 36.3% (71.7MPa), respectively was evident compared with the control (52.6 (5.5)MPa). CONCLUSIONS Disc-shaped specimens cut from round stock facilitated rapid fabrication of discs with uniform surface condition and demonstrated strength dependence was influenced by precementation parameters and resin-cementation variables.
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8.
In vivo effects of two acidic soft drinks on shear bond strength of metal orthodontic brackets with and without resin infiltration treatment.
Hammad, SM, Enan, ET
The Angle orthodontist. 2013;(4):648-52
Abstract
OBJECTIVES To evaluate the in vivo effects of two acidic soft drinks (Coca-Cola and Sprite) on the shear bond strength of metal orthodontic brackets with and without resin infiltration treatment. In addition, the enamel surface was evaluated, after debonding, using a scanning electron microscope. MATERIALS AND METHODS Sixty noncarious maxillary premolars, scheduled for extraction in 30 orthodontic patients, were used. Patients were randomly divided into two groups according to the soft drink tested (Coca-Cola or Sprite). In each group, application of resin infiltration (Icon. DMG, Hamburg, Germany) was done on one side only before bonding of brackets. Patients were told to rinse their mouth with their respective soft drink at room temperature for 5 minutes, three times a day for 3 months. Shear bond strength was tested with a universal testing machine. After shearing test, a scanning electron microscope was used to evaluate enamel erosion. Statistical analysis was performed by twoway analysis of variance followed by the least significant difference test. RESULTS The Coca-Cola group without resin infiltration showed the lowest resistance to shearing forces. Scanning electron micrographs of both groups after resin application showed a significant improvement compared with results without resin use, as the enamel appeared smoother and less erosive. CONCLUSION Pretreatment with the infiltrating resin has proved to result in a significant improvement in shear bond strength, regardless of the type of soft drink consumed.
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9.
Effect of chlorhexidine application on the long-term shear bond strength to dentin of a resin-modified glass ionomer.
Dursun, E, Le Goff, S, Ruse, DN, Attal, JP
Operative dentistry. 2013;(3):275-81
Abstract
PURPOSE The aim of this study was to investigate the effect of chlorhexidine digluconate (CHX) application on the shear bond strength (SBS) of a resin-modified glass ionomer cement (RMGIC) to polyalkenoic acid-preconditioned dentin after 24 hours, six months, and 12 months of water storage at 37°C. MATERIALS AND METHODS Cylindrical molds, placed on flat, polyalkenoic acid (Cavity Conditioner® [GC]) preconditioned dentin surfaces of 90 human teeth embedded in resin, were filled with Fuji II LC® (GC), a RMGIC, with (n=45) or without (n=45) the prior application of a 0.05% CHX solution. Within each group, SBS was determined after 24 hours (n=15), six months (n=15), and 12 months (n=15) of storage in water at 37°C. The results were analyzed with two-way analysis of variance followed by Tukey multiple means comparisons (p<0.05). The type of bond failure (adhesive/cohesive/mixed) was noted and the results were analyzed with chi-square test (p<0.05). RESULTS After 24 hours, the SBS of RMGIC was not significantly different with (9.0 ± 2.8 MPa) or without (8.3±0.6 MPa) the application of CHX. After six months, however, SBS increased significantly in the group without CHX (12.7±3.4 MPa) but remained unchanged in the CHX group (9.4±4.0 MPa). Similar results without CHX (12.6±3.8 MPa) and with CHX (9.5±3.2 MPa) were obtained after 12 months. No significant differences in the type of debonding were found between the various groups tested. CONCLUSION The application of 0.05% CHX after dentin preconditioning did not seem to have affected the 24-hour SBS of RMGIC. However, the six- and 12-month SBS was significantly lower for CHX-treated samples, possibly as a result of CHX interference with both the bonding mechanism and the maturation reaction of RMGIC.
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10.
Durable bonding to mechanically and/or chemically pre-treated dental zirconia.
Inokoshi, M, Kameyama, A, De Munck, J, Minakuchi, S, Van Meerbeek, B
Journal of dentistry. 2013;(2):170-9
Abstract
OBJECTIVES To evaluate the effect of mechanical and chemical surface pre-treatment on the bond durability of two composite cements to dental zirconia. METHODS Fully sintered IPS e.max ZirCAD (Ivoclar-Vivadent) blocks were either subjected to tribochemical silica sandblasting (CoJet, 3M ESPE) or not mechanically pre-treated. Next, the zirconia samples were either additionally pre-treated using one of two silane/MDP-combined ceramic primers (Clearfil Ceramic Primer, Kuraray; Monobond Plus, Ivoclar-Vivadent), or not further chemically pre-treated. Finally, two identically pre-treated zirconia blocks were bonded together using either a conventional BisGMA-based (Clearfil Esthetic Cement, Kuraray) or an MDP-based (Panavia F2.0, Kuraray) 'self-etch' dual-cure composite cement. The specimens were trimmed at the interface to a cylindrical hour-glass shape and stored for 7 days in distilled water (37°C), after which they were randomly exposed to one of three ageing protocols: (1) immersed in 37°C water for 10 days (10d); (2) subjected to 10,000 thermo-cycles (TC); or (3) immersed in 37°C water for 6 months (6m). After storage, the micro-tensile bond strength (μTBS) was determined in MPa (n=15-21/group). Fractographic analysis was performed using SEM. RESULTS Weibull analysis revealed the highest Weibull scale and shape parameters for the 'CoJet/Clearfil Ceramic Primer/Panavia F2.0/10d' combination. While the BisGMA-based composite cement Clearfil Esthetic Cement (Kuraray) bonded equally well to zirconia using either tribochemical silica sandblasting (CoJet, 3M ESPE) or not, sandblasting appeared indispensable for the MDP-based and more hydrophilic composite cement Panavia F2.0 (Kuraray). CONCLUSIONS Combined mechanical and chemical pre-treatment can best be recommended to durably bond to zirconia. CLINICAL SIGNIFICANCE As a standard procedure to durable bond zirconia to tooth tissue, both mechanical (tribochemical silica coating) and chemical (silane/MDP-combined ceramic primers) is clinically highly recommended.