Microtensile bond strength of dual-polymerizing cementing systems to dentin using different polymerizing modes

STATEMENT OF THE PROBLEM: The effectiveness of bond strength using dual-polymerizing cementing systems ([DCSs] defined as the combination of dual-polymerizing bonding agents and resin cements) used with indirect restorations has not been evaluated when used solely with the autopolymerizing mode. PURPOSE: This study evaluated the in vitro microtensile bond strength (MTBS) of fourth- and fifth-generation DCSs with indirect composite restorations either light polymerized or autopolymerized. MATERIAL AND METHODS: Occlusal dentin surfaces of 48 human third molars were exposed and flattened. Teeth were assigned to 8 groups (n=6) according to the DCS and polymerizing modes: All-Bond2/Duolink (AB2), Optibond/Nexus2 (OPT), Bond1/Lute-it (B1), and Optibond Solo Dual Cure/Nexus2 (SOLO). Bonding agents were applied to dentin surfaces and left in the unpolymerized state. Resin cements were applied to prepolymerized resin discs (2 mm thick/Z250), which were subsequently bonded to the dentin surfaces. The restored teeth were light polymerized according to manufacturers' instructions (PP/XL 3000) or allowed to autopolymerize (AP). Restored teeth were stored in water at 37 degrees C for 24 hours and were both mesio-distally and bucco-lingually sectioned to obtain multiple bonded beams (1.2 mm2 of cross-sectional area). Each specimen was tested in tension at a crosshead speed of 0.6 mm/min until failure. Data (MPa) were analyzed by 2-way analysis of variance and the Tukey post hoc test (alpha=.05). Failure patterns of tested specimens were analyzed using scanning electron microscopy. RESULTS: The mean (SD) MTBS values (MPa) were: AB2/PP: 36.9 (6.5); AB2/AP: 32.7 (7.3); B1/PP: 38.2 (7.0); B1/AP: 13.0 (4.2); SOLO/PP: 33.2 (7.2); SOLO/AP: 23.4 (3.4); OPT/PP: 30.8 (7.5); OPT/AP: 13.1 (5.8). The AP groups showed significantly lower MTBS than the PP groups (P<.0001), except for AB2, which showed no difference between polymerization modes (P=.2608). CONCLUSION: The autopolymerizing mode of some dual-polymerizing cement systems may not be effective in promoting bond strength.     

Effect of an antibacterial adhesive on the bond strength of three different luting resin composites

OBJECTIVES: Effect of a dentin adhesive system containing antibacterial monomer-MDPB (Clearfil Protect Bond) on the shear bond strength of all-ceramic-IPS Empress 2 restorations luted with three different dual-polymerizing systems (Variolink 2, RelyX ARC and Panavia F 2.0) to dentin was investigated. METHODS: One hundred and eight all-ceramic discs (2 x 3mm; IPS Empress 2) were fabricated and ultrasonically cleaned. The buccal surfaces of 108 non-carious extracted human premolars were flattened to expose dentin and subsequently polished with 600-grit wet silicon carbide paper. Three dual-polymerizing luting systems had test groups and control groups consisting of 18 samples each. For the test groups Clearfil Protect Bond was applied to the exposed dentin surfaces. Control groups received the original bonding procedures of each adhesive system. After the all-ceramic samples were luted to the teeth, thermocycling was performed 5000 times. Shear bond strengths were tested using Shimadzu Universal Testing Machine until failure. Analysis of fractured dentin surfaces were performed using Optical Microscope at x10 and x1000 magnifications and the images were analyzed with Image Analyzer. Data was analyzed with one-way ANOVA and Bonferroni test at a significance level of p<0.05. RESULTS: Mean shear bond strength data of the groups in MPa were; Variolink: 20.45+/-4.75, Variolink+Clearfil Protect Bond:29.32+/-2.37, RelyX ARC:18.82+/-3.19, RelyX ARC+Clearfil Protect Bond:25.58+/-4.05, Panavia F 2.0:17.11+/-2.98, Panavia F 2.0+Clearfil Protect Bond:24.40+/-7.46. Application of the antibacterial adhesive increased the shear bond strengths of all three dual-polymerizing systems to dentin (p=0.00). The surface analysis showed that most of the specimens showed the adhesive failure mode between the dentin and the composite luting agent interface. CONCLUSION: The antibacterial adhesive system Clearfil Protect Bond can be safely used to prevent the potential risk of complications resulting from bacterial activity regardless of affecting the bond strength of IPS Empress 2 restorations luted with the dual-polimerizing systems used in this study.     

Bond strength of adhesive luting systems to human dentin and their durability

Statement of problemThe durability of adhesive bonding systems to dentin is of importance for restoration longevity; therefore, new adhesive systems should be tested in vitro with long-term artificial aging before clinical application.PurposeThe purpose of this in vitro study was to investigate the bonding durability of 3 dual-polymerizing resins and 1 autopolymerizing resin to human dentin with their specific self-etching primers or adhesives.Material and methodsAcrylic resin tubes filled with composite resin were bonded to human dentin disks using either an autopolymerizing resin system (Panavia 21) or dual-polymerizing resin systems (Panavia V5, RelyX Ultimate, and Variolink Esthetic DC) together with the system-specific primer or adhesive. Tensile bond strength was tested after 3 days of water storage or after 150 days of water storage with 37 500 thermocycles (5 °C to 55 °C). The failure mode was evaluated by using a light microscope. In addition, representative specimens were examined by using a scanning electron microscope.ResultsAfter 3 days, the median tensile bond strengths ranged from 18.8 to 29.1 MPa. After artificial aging for 150 days, the median tensile bond strengths ranged from 14.7 to 25.6 MPa. The dual-polymerizing resins showed significantly higher bond strength than the autopolymerizing resin (P≤.05). Artificial aging with thermocycling had no statistically significant influence on tensile bond strength for the adhesive resin systems tested (P>.05). The failure mode was mainly adhesive for the autopolymerizing resin, whereas it was mainly cohesive for the dual-polymerizing resins.ConclusionsThe 3 tested dual-polymerization resin systems provided durable bond strengths to dentin which were higher than those of the autopolymerizing resin.     

Tensile bond strength of four resin luting agents bonded to bovine enamel and dentin

STATEMENT OF PROBLEM: The resistance to fracture of ceramic restorations depends on adequate bonding to tooth structure. The dental substrate and the types of resin luting agents used are believed to produce variability in adhesive properties. PURPOSE: The purpose of this study was to evaluate the tensile bond strength of 4 resin luting agents to bovine enamel and dentin. MATERIAL AND METHODS: Forty bovine incisors were embedded in acrylic resin and ground horizontally with water-cooled silicon carbide paper to expose enamel (20 teeth) and dentin at the enamel/dentin junction (20 teeth). Ten standard cone-shaped specimens with a 3-mm diameter base were prepared for each of the following resin cements: Resin Cement, Rely X ARC, Nexus, and Enforce. Five specimens of each material were bonded to enamel and the other 5 to dentin with these resin luting agents and their respective adhesive systems, according to the manufacturers' directions. After 7 days of storage in distilled water at 37 degrees C, specimens were subjected to tensile forces in a universal testing machine at a crosshead speed of 0.5 mm/min until fracture. Bond strength data were analyzed with analysis of variance for substrate and material. Means were compared with Tukey's test at the 0.05 level of significance. RESULTS: Analysis of variance disclosed that both substrate (P<.001) and material (P<.05) demonstrated statistically significant differences, but their interaction was not significant. The bond strengths (MPa) obtained for Resin Cement (11.5 +/- 3.0), Rely X ARC (11.4 +/- 3.1), Nexus (10.0 +/- 1.4), and Enforce (11.8 +/- 2.8) were statistically the same for enamel. For dentin, bond strengths (MPa) for Rely X ARC (9.6 +/- 1.8), Resin Cement (9.3 +/- 0.9), and Enforce (7.8 +/- 2.9) were significantly higher than for Nexus (3.5 +/- 0.8). Significantly higher bond strengths (MPa) were also observed for enamel (11.2 +/- 2.5) than dentin (7.5 +/- 1.6). CONCLUSION: Within the limitations of this study, tensile bond strengths of resin luting agents to enamel were higher than those to dentin, and the bond strength values of Nexus to dentin were significantly lower (P<.05) than the other cements tested.     

Effect of cyclic loading on the microtensile bond strengths of total-etch and self-etch adhesives

OBJECTIVE: To evaluate the effect of mechanical loading on the microtensile bond strength (MTBS) of five adhesive systems to dentin. METHODS: Flat dentin surfaces from human molars were divided into five groups and bonded with total-etch self-priming adhesives (Single Bond, Prime&Bond NT and Prime&Bond XP), two-step self-etching primer (Clearfil SE Bond) and an all-in-one adhesive (Etch&Prime 3.0), according to the manufacturers' instructions. Composite build-ups were constructed incrementally with Tetric Ceram. After 24 hours of water storage, half the specimens were load cycled (5000 cycles, 90 N). The teeth were then sectioned into beams of 1.0 mm2 cross-sectional area. Each beam was tested in tension in an Instron machine at 0.5 mm/minute. Data were analyzed by two-way ANOVA and Student Newman Keuls multiple comparisons tests (p<0.05). Results: Clearfil SE Bond and Single Bond attained higher MTBS than the other three adhesives. Prime&Bond NT and Prime&Bond XP performed equally, and Etch&Prime 3.0 resulted in the lowest MTBS. After mechanical loading, MTBS decreased in all groups except Prime&Bond XP. Clearfil SE Bond, Single Bond and Prime&Bond XP obtained higher MTBS than Prime&Bond NT. Specimens bonded with Etch&Prime 3.0 resulted in premature failures and MTBS could not be measured. Clinical RELEVANCE: When using Etch&Prime 3.0, bond structures did not withstand mechanical loading, which may have an influence on the long-term success of restorations. If dentin is acid-etched, alcohol-based adhesive systems showed higher bond strength after mechanical loading.     

Effect of solvent type on microtensile bond strength of a total-etch one-bottle adhesive system to moist or dry dentin

This study evaluated the effect of organic solvent (acetone or ethanol) on the microtensile bond strengths (MTBS) of an adhesive system applied to dry and moist dentin. Sixteen extracted human third molars were ground to expose a flat occlusal dentin surface and acid etched for 20 seconds (20% phosphoric acid gel, Gluma Etch 20 Gel, Heraeus/Kulzer). After rinsing the acid etchant, an ethanol-based one-bottle adhesive system was applied to the mesial half of the occlusal dentin surface. An acetone-based, one-bottle adhesive system was applied to the distal half of the ground dentin surface. The teeth were randomly assigned to groups. In Group 1, the etched dentin was thoroughly air dried and an ethanol-based one-bottle adhesive system was applied (Gluma Comfort Bond, Heraeus/Kulzer) (GCB). In Group 2, the etched dentin was thoroughly air dried and an acetone-based one-bottle adhesive system was applied (Gluma One Bond, Heraeus/Kulzer)(GOB). In Group 3, excess moisture was removed after acid etching, leaving a moist dentin surface and a one-bottle ethanol-based adhesive was applied (Gluma Comfort Bond). In Group 4, excess moisture was removed after acid etching, leaving a moist dentin surface and an acetone-based adhesive was applied (Gluma One Bond). A hybrid resin composite (Venus, Heraeus/Kulzer) was applied to the bonded surface in four 1-mm increments and light cured according to manufacturer's directions. The specimens were then sectioned with a slow-speed diamond saw in two perpendicular directions to obtain sticks with a cross-section of 0.5 +/- 0.05 mm2. The microtensile bond strength (MTBS) test was performed with a Bencor device in an Instron machine at a crosshead speed of 0.5 mm/minute. The data were subjected to a two-way ANOVA and Scheffé Post hoc test (p < 0.05). The experimental MTBS measured for dry dentin were Group 1 = 37.0 +/- 10.6 and Group 2 = 34.7 +/- 9.0 in MPa (mean +/- SD); and on moist dentin, Group 3 = 50.7 +/- 11.0 and Group 4 = 38.5 +/- 10.5 in MPa (mean +/- SD). The ethanol based adhesives resulted in higher MTBS than acetone-based adhesive (p < 0.008) and bonding to moist dentin resulted in higher MTBS (p < 0.001). GCB applied on moist dentin resulted in statistically higher bond strengths than the other groups. The highest MTBS were achieved with the use of an ethanol-based adhesive to moist dentin.     

Bond strength of a resin cement to dentin using the resin coating technique

The aim of this study was to evaluate the bond strength of a resin cement to dentin using different adhesive systems (AS) in the presence or absence of a low-viscosity composite liner (Protect Liner F - PLF) applied over the bonded dentin. The adhesive systems selected were: AdheSE/Vivadent (AD); Clearfil Protect Bond/Kuraray (CP); One-Up Bond F/Tokuyama (OU); Single Bond/3M ESPE (SB); Tyrian SPE/One-Step Plus/Bisco (TY); Xeno III/Dentsply (XE) and Unifil Bond/GC (UN). After removing the labial and lingual enamel surfaces of bovine incisors, dentin fragments were prepared and randomly divided into 15 groups (n = 8). The dentin substrates were bonded with the AS and the PLF was applied or not before application of the resin cement (Panavia F, Kuraray). In the control group, the ED Primer (ED) and the resin cement without PLF were used. The AS, PLF and resin cement tested were used according to the manufacturers' instructions, and all treated dentin surfaces were temporized. After water storage for one week, three cylinders of resin cement were applied to each bonded dentin surface, using tygon tubing molds. The specimens were subjected to micro-shear testing and the data were statistically analyzed (two-way ANOVA, Tukey and Dunnett tests, p < 0.05). The observed mean shear bond strengths in MPa were: ED: 20.2 +/- 2.3; AD: 30.3 +/- 6.5; CP: 25.3 +/- 4.4; OU: 28.3 +/- 6.6; SB: 25.6 +/- 6.9; TY: 24.5 +/- 2.5; XE: 17.3 +/- 3.4; UN: 28.4 +/- 6.2; AD+PLF: 32.8 +/- 4.1; CP+PLF: 29.9 +/- 3.9; OU+PLF: 34.1 +/- 4.1; SB+PLF: 29.5 +/- 8.2; TY+PLF: 29.2 +/- 3.9; XE+PLF: 32.8 +/- 6.7; UN+PLF: 32.2 +/- 4.5. The bond strength of the resin cement to dentin using the tested AS was increased when the low-viscosity composite liner was applied.     

Microtensile bond strength between adhesive cements and root canal dentin.

OBJECTIVES: The hypotheses tested were that the bond strength of adhesive cements to root canal dentin (1) would be reduced as a function of configuration factor, polymerization process and type of luting material and (2) would be lowered near the apex of the tooth. METHODS: Human canines and premolars were prepared for post cementation using Single Bond/Rely X ARC, ED Primer/Panavia F, C and B Metabond, and Fuji Plus. The specimens were divided into two groups. For intact roots, the posts were luted using standard clinical procedures. For flat roots, the posts were applied directly into flat ground canals. All roots were sectioned into 0.6 mm thick slices, trimmed mesio-distally and stressed to failure at 1 mm/min. The muTBS of each slab was calculated as the force at failure divided by the bonded cross-sectional surface area. The results were compared using a one-way ANOVA and Tukey multiple comparison intervals (alpha=0.05). Least squares linear regression analysis was used to assess the effect of dentin location on bond strength. RESULTS: All cements showed significantly (p相似文献   

Effects of adhesive liner and provisional cement on the bond strength of nickel/chrome/beryllium alloy cemented to dentin.

OBJECTIVE: Treating teeth with adhesive agents before placing a provisional restoration can prevent tooth sensitivity. This study evaluated the bond strength of resin cements to dentin treated with 2 adhesive agents and 2 provisional cements. METHODS AND MATERIALS: Extracted human molars were prepared by exposing dentin and were treated with either Prime & Bond NT or Clearfil SE Bond. After a simulated impression technique, the teeth were provisionalized with either a eugenol or noneugenol temporary cement. Teeth were cleaned for bonding by either mechanical removal of the cement or use of an acid conditioner. Panavia F and Calibra resin cements were used to cement nickel/chrome/beryllium alloy to the tooth surfaces, and the specimens were debonded. Mean shear bond strengths for each group were calculated. RESULTS: Mean shear bond strengths ranged from 26.6 +/- 5.8 MPa for Calibra bonded to dentin treated with Prime & Bond NT, a noneugenol cement, and mechanically cleaned, to 10.6 +/- 4.4 MPa for Panavia F bonded to unlined (no adhesive) dentin treated with a eugenol cement and mechanically cleaned. Of the 14 groups tested, significant differences were observed related to the adhesives and resin cements. Both temporary cements reduced the bond to dentin not treated with a resin adhesive. Use of an acid conditioner for cleaning the temporary cement also reduced bond strengths in all groups. CONCLUSIONS: Placement of a dentin adhesive before provisionalization may prevent the temporary cement from affecting the bond of the final resin cement to the tooth. For the products used in this study, use of phosphoric acid to clean the tooth surface is not recommended.     

Dentin regional bond strength of self-etch and total-etch adhesive systems

OBJECTIVES: To evaluate the microtensile bond strength (MTBS) of self-etch (with or without H(3)PO(4)-etching) and total-etch bonding systems bonded to different regions of dentin. METHODS: Long flat dentin cavity preparations extending from top-crown to root-apex within the same tooth were performed and bonded: using two-step (Clearfil SE Bond/SEB, Resulcin Aqua Prime/RES) and one-step (Etch & Prime 3.0/EP, One-Up Bond F/OUB, Prompt L-Pop/PLP, Solist/SOL and Futurabond/FUT) self-etch adhesives; these same adhesives were also applied following H(3)PO(4)-etching of dentin and finally two more groups were bonded with total-etch adhesives (Single Bond/SB and Prime & Bond NT/PBNT). Build-ups of resin composite were constructed incrementally to ensure sufficient bulk for the MTBS test and the different regions of dentin were identified by painting with different colours on the top of the resin composite. Specimens were sliced into beams and tested in tension. ANOVA and multiple comparisons tests were used (p<0.05). RESULTS: Regardless of the tested dentin region, SEB attained the highest MTBS to smear layer-covered surfaces (i.e., coronal dentin: 42.7MPa), while H(3)PO(4)-etching of dentin hampered bonds (i.e., coronal dentin: 27.7MPa). When bonding with PBNT, SB, RES, EP, PLP, SOL and FUT, MTBS was similar for different dentin regions. H(3)PO(4)-etching of dentin did not alter the attained MTBS. SIGNIFICANCE: SEB yielded the highest MTBS to all regions of dentin. When bonding to parallel-cut dentin, previous H(3)PO(4)-etching of dentin did not increase MTBS and differences in bond strength among dentin regions were absent.     

Durability of enamel bonding using two-step self-etch systems on ground and unground enamel

This study examined the early and long-term microtensile bond strengths (MTBS) and interfacial enamel gap formation (IGW) of two-step self-etch systems to unground and ground enamel. Resin composite (Filtek Z250) buildups were bonded to proximal enamel surfaces (unground, bur-cut or SiC-treated enamel) of third molars after the application of four self-etch adhesives: a mild (Clearfil SE Bond [SE]), two moderate (Optibond Solo Plus Self-Etch Primer [SO] and AdheSE [AD]) and a strong adhesive (Tyrian Self Priming Etchant + One Step Plus [TY]) and two etch-and-rinse adhesive systems (Single Bond [SB] and Scotchbond Multi-Purpose Plus [SBMP]). Ten tooth halves were assigned for each adhesive. After storage in water (24 hours/37 degrees C), the bonded specimens were sectioned into beams (0.9 mm2) and subjected to microTBS (0.5 mm/minute) or interfacial gap width measurement (stereomicroscope at 400x) either immediately (IM) or after 12 months (12M) of water storage. The data were analyzed by three-way repeated measures ANOVA and Tukey's test (alpha=0.05). No gap formation was observed in any experimental condition. The microTBS in the Si-C paper and diamond bur groups were similar and greater than the unground group only for the moderate self-etch systems (SO and AD). No reductions in bond strength values were observed after 12 months of water storage, regardless of the adhesive evaluated.     

Effect of thermal aging on the tensile bond strength at reduced areas of seven current adhesives

The purpose of this study was to determine the micro-tensile bond strength (MTBS) to dentin of seven adhesive systems (total and self-etch adhesives) after 24 h and 5,000 thermocycles. Dentin surfaces of human third molars were exposed and bonded with two total-etch adhesives (Adper Scotchbond 1 XT and XP Bond), two two-step self-etch adhesives (Adper Scotchbond SE and Filtek Silorane Adhesive System) and three one-step self-etch adhesives (G-Bond, Xeno V and Bond Force). All adhesive systems were applied following manufacturers’ instructions. Composite buildups were constructed and the bonded teeth were then stored in water (24 h, 37 °C) or thermocycled (5,000 cycles) before being sectioned and submitted to MTBS test. Two-way ANOVA and subsequent comparison tests were applied at α = 0.05. Characteristic de-bonded specimens were analyzed using scanning electron microscopy (SEM). After 24 h water storage, MTBS values were highest with XP Bond, Adper Scotchbond 1 XT, Filtek Silorane Adhesive System and Adper Scotchbond SE and lowest with the one-step self-etch adhesives Bond Force, Xeno V and G-Bond. After thermocycling, MTBS values were highest with XP Bond, followed by Filtek Silorane Adhesive System, Adper Scotchbond SE and Adper Scotchbond 1 XT and lowest with the one-step self-etch adhesives Bond Force, Xeno V and G-Bond. Thermal aging induced a significant decrease in MTBS values with all adhesives tested. The resistance of resin–dentin bonds to thermal-aging degradation was material dependent. One-step self-etch adhesives obtained the lowest MTBS results after both aging treatments, and their adhesive capacity was significantly reduced after thermocycling.     

Does the acidity of self-etching primers affect bond strength and surface morphology of enamel?

PURPOSE: This study examined the ultrastructure and microtensile bond strengths (TBS) of self-etching (with different acidity) and conventional adhesive systems bonded to unground enamel. MATERIALS AND METHODS: Resin composite (Filtek Z250) buildups were bonded to unground enamel surfaces of third molars after adhesive application with the following materials: Clearfil SE Bond (CSE); Optibond Solo Plus Self-Etch (OP); Tyrian Self Priming Etching (TY), and the controls Scotchbond Multi-Purpose Plus (SBMP) and Single Bond (SB). Six teeth were assigned to each material. After storage in waterfor 24 h at 37 degrees C, the bonded specimens were sectioned into beams of approximately 0.8 mm2 and subsequently subjected to microTBS testing at a crosshead speed of 0.5 mm/min. The average values were subjected to one-way ANOVA (alpha = 0.05). The effect of surface conditioning of each material was observed under scanning electron microscopy (SEM). RESULTS: The highest resin-enamel bond strength was observed for SBMP (22.7 +/- 5.2) and SB (26.7 +/- 5.2 MPa). The lowest mean bond strengths were 10.9 +/- 3.2 and 7.8 +/- 1.5 MPa for TY and OP, respectively. CSE showed an intermediate performance (18.7 +/- 4.6 MPa). An overall increase in porosity was evident along the entire enamel surface treated with the self-etching primers; however, no selective demineralization similar to that with 35% phosphoric acid was observed. CONCLUSION: The highest bond strength means and the more retentive etching pattern were observed for the two-step etch-and-rinse adhesives. Among the self-etching systems studied, Clearfil SE Bond should be preferred.     

Effect of bur-cut dentin on bond strength using two all-in-one and one two-step adhesive systems

PURPOSE: To compare the microtensile bond strength (MTBS) of two all-in-one adhesive systems and one experimental two-step self-etching adhesive system to two types of bur-cut dentin. MATERIALS AND METHODS: Using one of the three adhesives, Xeno CF Bond (Xeno), Prompt L-Pop (PL), or the experimental two-step system ABF (ABF), resin composite was bonded to flat buccal and root dentin surfaces of eight extracted human premolars. These surfaces were produced using either regular-grit or superfine-grit diamond burs. After storage overnight in 37 degrees C water, the bonded specimens were sectioned into six or seven slices approximately 0.7 mm thick perpendicular to the bonded surface. They were then subjected to microtensile testing. The surfaces of the fractured specimens were observed microscopically to determine the failure mode. In addition, to observe the effect of conditioning, the two types of bur-cut dentin surfaces were conditioned with the adhesives, rinsed with acetone, and observed with SEM. RESULTS: When Xeno and PL were bonded to dentin cut with a regular-grit diamond bur, MTBS values were lower than to superfine bur-cut dentin, and failures occurred adhesively at the interface, whereas the experimental two-step adhesive showed no significant difference in microtensile bond strength between two differently cut surfaces. CONCLUSION: The all-in-one adhesives tested here improved bond strengths when bonded to superfine bur-cut dentin as a substrate, whereas the experimental two-step adhesive system showed unchanged bonding to both regular and superfine bur-cut dentin surfaces.     

Effect of different bur grinding on the bond strength of self-etching adhesives

This study compared the microtensile bond strength (MTBS) of three all-in-one adhesive systems and a two-step system using two types of burs to prepare the dentin surfaces. Flat coronal surfaces of 24 extracted human molars were produced using either regular-grit or superfine-grit diamond burs. Resin composite was then bonded to equal numbers of these surfaces using one of the four adhesives: Clearfil SE Bond (CSE), G-Bond (GB), SSB-200 (SSB) or Prompt L-Pop (PLP). After storage for 24 hours in 37 degrees C distilled water, the bonded teeth were sectioned into slices (0.7-mm thick) perpendicular to the bonded surface. The specimens were then subjected to microtensile testing and the bond strengths were calculated at failure. Bond strength data were analyzed by two-way ANOVA and the GamesHowell test for interaction between adhesive and type of cut dentin. The fractured surfaces were observed by SEM to determine the failure mode. In addition, to observe the effect of conditioning, equal numbers of the two bur-cut dentin surfaces of eight additional teeth were conditioned with the adhesives and observed by SEM. Based on the results, when CSE and SSB were bonded to dentin cut with a regular-grit diamond bur, the MTBS values were significantly lower than that of superfine bur-cut dentin; whereas, GB and PLP showed no significant differences in MTBS between the two differently cut surfaces. SEM observation of the fractured surfaces revealed a mixed mode (adhesive in some areas and cohesive in others in the same sample) of failure in all specimens except PLP, which showed cohesive failure within the adhesive for both types of bur preparation. Generally, SEMs of the conditioned surfaces using both types of burs showed partial removal of the smear layer for CSE, minimal for GB and SSB and complete removal for PLP. In conclusion, when cutting dentin, selecting the proper bur type is important for improving the bond strength of some self-etching adhesive systems.     

Influence of time and adhesive system on the extrusion shear strength between feldspathic porcelain and bovine dentin.

OBJECTIVES: The behavior of dual-cure cements over time remains unclear. This study evaluated the extrusion shear strength of the bond between feldsphatic porcelain and bovine dentin at different time intervals, using three adhesive systems based on dual-cure cements and one based on a self-cure cement. METHODS: The adhesive systems evaluated included: C&B/One-Step, Enforce/Prime&Bond NT Dual-Cure, RelyX ARC/Single Bond and Variolink II/Syntac SC. Discs of bovine root dentin, 2.5 mm thick, had the root canal prepared with a standardized taper. Porcelain truncated cones etched with 4% hydrofluoric acid and silanized were bonded into the perforations. The extrusion shear test was performed after 15 min, 4 h, 12 h, 24 h, and 7 days. Data were analyzed using the Weibull distribution. The failure mode was accessed by stereomicroscope and SEM. RESULTS: Statistical differences were found between 15 min and 7 days for Variolink II/Syntac SC and RelyX ARC/Single Bond, and between 15 min and 24 h for Enforce/Prime&Bond NT Dual-Cure. For C&B/One-Step, difference was found between 15 min and 4 h. Between 24 h and 7 days, only the system RelyX ARC/Single Bond showed a significant increase in the characteristic strength. SEM analysis revealed that the failure involved the hybrid layer/dentin or the hybrid layer/adhesive interfaces, regardless of the time interval and adhesive system. SIGNIFICANCE: High characteristic strengths were observed after 15 min when dual-cure cements were used. In general, the values found at 24 h or 7 days were higher than at 15 min. However, there was always a considerable probability of bonding failure at low stress levels for all the systems tested.     

Shear bond strength of an autopolymerizing core buildup composite bonded to dentin with 9 dentin adhesive systems

STATEMENT OF PROBLEM: Clinicians have reported unexpected debonding of autopolymerizing composite core buildups. It has been postulated that dentin adhesive systems that incorporate a combined primer-adhesive may be incompatible with autopolymerizing composites. If so, large numbers of existing restorations may be predestined for early failure. PURPOSE: This in vitro investigation examined the shear bond strength values of an autopolymerizing core buildup composite bonded to dentin with 9 dentin adhesive systems. MATERIAL AND METHODS: Cylinders of the core buildup composite (2.38-mm diameter) were bonded to moist dentin according to the manufacturers' instructions. Specimens were stored in 37 degrees C water for 1 week, thermocycled (5 degrees C to 55 degrees C, 30-second intervals, 1000 cycles), and returned to water storage overnight. Specimens then were debonded with a universal testing machine at 1.0 mm/min, with results recorded in megapascals. Data were statistically analyzed with a Kruskal-Wallis test, with pairwise Wilcoxon rank sum (Mann-Whitney) tests used to determine significant (P<.05) differences between groups. RESULTS: The dentin adhesive systems in order of decreasing median bond strength were Optibond FL > One Step, All-Bond 2, Clearfil SE, Amalgambond Plus > Single Bond, Optibond Solo Plus, Tenure > Scotchbond MP. CONCLUSION: No predictable relationship was found between the general formulation of the dentin adhesive agents and shear bond strength values. Material incompatibilities were judged to be dependent on formulation.     

Microtensile bond strength of photoactivated and autopolymerized adhesive systems to root dentin using translucent and opaque fiber-reinforced composite posts

STATEMENT OF PROBLEM: The use of fiber-reinforced composite resin posts in endodontically treated teeth has increased. However, selecting an adhesive system that provides reliable and long-lasting bonding to root canal dentin remains difficult. PURPOSE: This study evaluated the microtensile bond strength of 2 adhesive systems to root dentin and 2 different fiber-reinforced composite resin posts. MATERIAL AND METHODS: Forty single-rooted teeth were instrumented, and root canals were prepared for translucent (Light Post [LP]) or opaque (Aestheti Post [AP]) quartz fiber-reinforced composite resin posts. Two adhesive systems were used: Scotchbond Multi-Purpose Plus (SBMP) (autopolymerized) as a control group, and Single Bond (SB) (photoactivated). Teeth were assigned to 4 groups (n=10): SBMP+LP, SBMP+AP, SB+LP, SB+AP. After post cementation, roots were perpendicularly sectioned into 1-mm-thick slices, which were trimmed to obtain dumbbell-shaped specimens. The specimens were divided into 3 regions: cervical (C), middle (M), and apical (A). To determine the bond strength, the bonding area of each specimen was calculated, and specimens were attached to a device to test microtensile strength at a crosshead speed of 1 mm/min. Data were analyzed using 3-way analysis of variance and the Tukey test (alpha=.05). Fractured specimens were examined under a x 25 stereomicroscope to determine the mode of fracture. RESULTS: There were significant differences only among root dentin regions (P<.001). The cervical third (9.16 +/- 1.18 MPa) presented higher mean bond strength values, especially for SBMP. Middle and apical regions demonstrated lower values (7.08 +/- 0.92 and 7.31 +/- 0.60 MPa, respectively). Adhesive and post main factors did not demonstrate significance. Also, no interaction was significant. No cohesive fractures within resin cement, fiber-reinforced composite resin post, or root dentin were identified. CONCLUSIONS: Both adhesive systems tested demonstrated reliable bonding when used with translucent and opaque fiber-reinforced composite posts.     

Push-out bond strengths of endodontic posts bonded with different resin-based luting cements

PURPOSE: To compare the push-out bond strengths of endodontic posts bonded with different resin-based luting cements and to verify that bond strengths did not vary with cement thickness. METHODS: 48 root canals were shaped using 6% NiTi rotary files, obturated with gutta-percha and AH Plus sealer and prepared for post cementation using Panavia F, Parapost cement, SuperBond and Unicem Rely X. All roots were sectioned into 0.7 mm thick slices and digital photographs of each slice were analyzed using Scion Image to measure the surface area of the luting cement. The root slices were stressed to failure at 1 mm/minute using a push-out test. Push-out strength was calculated as the force at failure divided by the bonded surface area. Least squares linear regression analysis was used to assess the effect of cement thickness on bond strength. Fractured specimens were further observed under the SEM. RESULTS: Mean push-out bond strengths were: Panavia F (8.8 +/- 3.6 MPa), Parapost cement (9.1 +/- 4.4 MPa) SuperBond (14.6 +/- 2.9 MPa) and Rely X Unicem (12.4 +/- 3.3 MPa). The Panavia F and the Parapost cement were not significantly different from each other, but both were significantly lower (P < or = 0.05) than SuperBond and Rely X Unicem. Although there were large variations in cement thickness, the cementation of fiber posts with thicker cement layers did not affect the performance of the adhesive luting cements applied to root canal dentin.     

Microtensile bond strength of total-etch and self-etch adhesives to the enamel walls of Class V cavities

PURPOSE: To determine the difference in microtensile bond strengths (MTBS) of resin-based composite bonded to the enamel of cavity preparations using a conventional or a self-etching adhesive. METHODS: Buccal and lingual Class V cavities were prepared in each of 12 caries-free human molars. Six teeth were randomly selected to be restored with Spectrum TPH resin-based composite and Prime & Bond NT adhesive. The remaining six teeth were restored with the same composite and Prompt L-Pop self-etching adhesive. Enamel/composite sticks were cut from each specimen and subjected to microtensile bond testing. Each debonded specimen was evaluated by SEM to determine the mode of failure. RESULTS: The mean MTBS for Prime & Bond NT specimens was 15.2+/-13.1 MPa. The mean MTBS for Prompt L-Pop self-etching adhesive samples was 18.2+/-14.3 MPa. ANOVA demonstrated no statistically significant difference between the mean MTBS associated with the two adhesives (P> 0.05). The results of SEM analysis revealed that the bonding failures occurred primarily at the interface between the adhesive and the enamel, suggesting a primarily adhesive failure.