Self-etch vs etch-and-rinse adhesives: effect of thermo-mechanical fatigue loading on marginal quality of bonded resin composite restorations.

OBJECTIVE: This study evaluated the marginal integrity of dentine adhesives bonded to enamel and dentine, before and after thermo-mechanical loading (TML). METHODS: MO cavities with proximal boxes beneath the CEJ were prepared in extracted human third molars. Direct resin composite restorations (Tetric Ceram) were bonded with 3-step etch-and-rinse (Syntac Classic, Solobond Plus, OptiBond FL), 2-step etch-and-rinse (Admira Bond, Single Bond), 2-step self-etch (AdheSE, Clearfil SE Bond), and 1-step self-etch (all-in-one) adhesives (Adper Prompt, Xeno III, iBond). Marginal gaps were analyzed using SEM of epoxy resin replicas. Bonded interfaces before TML were examined with TEM to identify pre-existing attributes for subsequent marginal disintegration. RESULTS: In enamel, high percentages of gap-free margins were initially identified for all adhesives. After TML, etch-and-rinse adhesives exhibited significantly higher percentages of gap-free margins (approximately 90%) compared with two-step self-etch (approximately 75%) and all-in-one (approximately 55%) adhesives (p<0.05). iBond did not completely etch through the enamel smear layer. In dentine, 89-100% gap-free margins were initially observed. After TML, there were no statistical differences among etch-and-rinse (62-70%) and two-step self-etch (62-63%) adhesives (p>0.05). The all-in-one adhesives exhibited significantly less gap-free margins (<40%) in dentine (p<0.05), with iBond showing the worst marginal integrity (15%). The presence of pre-existing water channels within the adhesives probably expedited water sorption when restorations were under functional stresses. CONCLUSION: Enamel bonding was more effective with phosphoric acid-etching. Etch-and-rinse and 2-step self-etch adhesives showed promising marginal adaptation to dentine and may have a better clinical prognosis than the all-in-one bonding approach.     

Effect of cavity configuration and aging on the bonding effectiveness of six adhesives to dentin.

OBJECTIVES: The purpose of this study was to determine the effect polymerization contraction stress may have on bond durability. METHODS: Bonding effectiveness was assessed by micro-tensile bond strength testing (muTBS) and electron microscopy. The muTBS to flat dentin surfaces and in standardized cavities was determined (this after 1 day as well as 1 year water storage). Six adhesives representing all current classes were applied: two etch-and-rinse (OptiBond FL, Kerr; Scotchbond 1, 3M ESPE), two self-etch (Clearfil SE Bond, Kuraray; Adper Prompt, 3M ESPE) and two glass-ionomer (Fuji Bond LC, GC; Reactmer, Shofu) adhesives. RESULTS: The conventional 3-step etch-and-rinse adhesive OptiBond FL bonded most effectively to dentin, and appeared insensitive to polymerization shrinkage stress and water degradation. The 2-step self-etch adhesive Clearfil SE Bond most closely approached this superior bonding effectiveness and only slightly lost bond strength after 1-year water exposure. The 2-step etch-and-rinse adhesive Scotchbond 1 and the 'strong' 1-step self-etch adhesive Adper Prompt appeared very sensitive to cavity configuration and water-aging effects. The 2-step resin-modified glass-ionomer adhesive Fuji Bond LC only suffered from shrinkage stress, but not from 1-year water-exposure. Remarkable also is the apparent repairability of the 'mild' 1-step glass-ionomer adhesive Reactmer when stored for 1 year in water, in spite of the very low 1-day muTBS. SIGNIFICANCE: Simplified bonding procedures do not necessarily imply improved bonding performance, especially in the long term.     

Comparison of enamel and dentin microshear bond strengths of a two-step self-etching priming system with five all-in-one systems

Data on the adhesive strength of new all-in-one adhesives are still relatively limited. This study compared the microshear bond strengths of five recent all-in-one self-etching priming systems (G-Bond, One-Up Bond-F Plus, Clearfil S3 Bond, Adper Prompt L-Pop and Go!) with a widely used two-step self-etching priming system (Clearfil SE Bond). Human molars were sectioned and finished with 600-grit SiC paper. Both enamel and dentin were bonded using adhesives with a 0.7 mm bonding diameter. Bond strengths were tested using a microshear bond test method at a crosshead speed of 1 mm/minute. The mean bond strengths and standard deviations were calculated and analyzed using ANOVA and the Tukey's HSD test. Results showed the two-step self-etching system had significantly higher bond strengths to dentin. However, for enamel bond strength, Clearfil SE Bond showed no statistical difference to G-Bond and Go!; however, all of the other materials were statistically lower. It is necessary to examine these new materials clinically to determine their efficacy.     

Bonding to enamel and dentin using self-etching adhesive systems.

OBJECTIVES: This study investigated the effectiveness of three different dentin adhesive systems on the adhesion of resin composite to both dentin and enamel. METHOD AND MATERIALS: The flat dentin and enamel surfaces of 60 extracted human molar teeth were exposed by wet grinding with 600-grit silicon carbide paper. One total-etch self-priming adhesive system (Prime & Bond NT), one two-step self-etching primer adhesive system (Clearfil SE Bond), and one "all-in-one" self-etching adhesive system (Prompt L-Pop) were evaluated. Each bonding system was applied according to the manufacturer's instructions and followed by composite (TPH Spectrum) application. Twenty-four hours after bonding, the teeth were subjected to shear testing. There were 10 replicates for each group. RESULTS: Prompt L-Pop exhibited significantly higher bond strength values to enamel (27 +/- 4.2 MPa) than all other groups. There were no statistically significant differences for shear bond strength to dentin among adhesives. Prompt L-Pop showed the statistically significantly higher bond strength to enamel than dentin. There were no statistically significant differences between the enamel and dentin bond strengths of Clearfil SE Bond and Prime & Bond NT. CONCLUSIONS: The self-etching adhesive systems produced high bond strengths to human coronal dentin and ground enamel surfaces. These materials seem to be very promising for further clinical applications, and the results are very encouraging for the clinical success of these simplified adhesive systems. The self-etching adhesive systems produced even better bond strengths to both enamel and dentin than conventional total-etch systems, especially the "all-in-one" system, which produced the highest bond strength to enamel.     

In vitro evaluation of bonding effectiveness to dentin of all-in-one adhesives

Objectives

The study was aimed at assessing the bonding potential of all-in-one adhesives to dentin.

Methods

The microtensile bond strength of the all-in-one adhesives Bond Force (Tokuyama), AdheSE One (Ivoclar-Vivadent), and Xeno V (Dentsply) was measured in comparison with the etch-and-rinse system XP Bond (Dentsply). The ultrastructural characteristics of dentin–adhesive interface were observed under scanning electron microscope (SEM). Twenty human extracted third molars had their mid-coronal dentin exposed and ground with wet 600-grit SiC paper in order to create a standardized smear layer. Bonding procedures were performed according to the manufacturers’ instructions and microtensile beams were obtained with the “non-trimming” technique. The bond strengths in MPa were statistically analyzed including pre-test failures as “zero” values (Kolmogorov–Smirnov test, Levene's test, One-Way ANOVA, Tukey's test p < 0.05).

Results

The following bond strengths were recorded in MPa (mean ± standard deviation): AdheSE One 31.7 ± 21.3; Xeno V 42.8 ± 26.4; Bond Force 43.3 ± 22.1; XP Bond 51.9 ± 18.6. The statistical analysis demonstrated that the bond strengths achieved by Bond Force and Xeno V were similar to that of the etch-and-rinse adhesive, whereas the bond strength of AdheSE One was significantly lower. A distinct hybrid layer with resin tags was seen only in XP Bond specimens. All-in-one adhesives demonstrated a rather superficial interaction with the dentin substrate.

Conclusions

Although the strongest bond to dentin was established by the etch-and-rinse system, however the all-in-one adhesives containing organic solvents reached bond strength levels that were comparable from a statistical point of view.     

Shear Bond Strengths of Two Composite Core Materials After Using All-in-One and Single-Bottle Dentin Adhesives

PURPOSE: The purpose of this study was to compare the shear bond strengths of 2 composite core materials after using all-in-one and single-bottle dentin bonding materials. MATERIAL AND METHODS: The occlusal surfaces of 100 extracted, intact human third molars were ground to expose a flattened area of dentin and polished with 600-grit silicon carbide paper. Specimens were divided into 5 main groups (n= 20). Three all-in-one (AQ Bond, One-Up Bond, Xeno-CF Bond) and 2 single-bottle adhesives (Single Bond, One-Step Plus) were used. Each group was further divided into 2 subgroups. Ti-Core and Built-it F.R. core materials were applied using a translucent plastic ring (diameter: 3 mm, height: 5 mm). After storage in 37 degrees C water for 24 hours, shear bond strengths were measured using a Universal testing machine with a crosshead speed of 0.5 mm/min. Debonded dentin surfaces were examined with SEM. Two-way analysis of variance (ANOVA) and multiple comparison (Tukey) tests were used for statistical analysis of data. RESULTS: Two-way ANOVA revealed that the type of core material did not significantly influence the shear bond strength (p > 0.05), whereas there were significant differences in shear bond strength among the types of bonding agents (p < 0.0001). Shear bond strengths for single-bottle adhesive systems were significantly higher than those for all-in-one adhesive systems (p < 0.05). Furthermore, the interaction of these 2 parameters was not significant (p > 0.05). The fracture modes were predominantly adhesive for all-in-one adhesives and cohesive for single-bottle adhesives. CONCLUSION: Bonding of composite core materials with the newly developed all-in-one dentin adhesives produced lower shear bond strengths as compared with single-bottle adhesives.     

Adhesion of resin composite core materials to dentin

PURPOSE: This study determined (1) the effect of polymerization mode of resin composite core materials and dental adhesives on the bond strength to dentin, and (2) if dental adhesives perform as well to dentin etched with phosphoric acid as to dentin etched with self-etching primer. MATERIALS AND METHODS: Human third molars were sectioned 2 mm from the highest pulp horn and polished. Three core materials (Fluorocore [dual cured], Core Paste [self-cured], and Clearfil Photo Core [light cured]) and two adhesives (Prime & Bond NT Dual Cure and Clearfil SE Bond [light cured]) were bonded to dentin using two dentin etching conditions. After storage, specimens were debonded in microtension and bond strengths were calculated. Scanning electron micrographs of representative bonding interfaces were analyzed. RESULTS: Analysis showed differences among core materials, adhesives, and etching conditions. Among core materials, dual-cured Fluorocore had the highest bond strengths. There were incompatibilities between self-cured Core Paste and Prime & Bond NT in both etched (0 MPa) and nonetched (3.0 MPa) dentin. Among adhesives, in most cases Clearfil SE Bond had higher bond strengths than Prime & Bond NT and bond strengths were higher to self-etched than to phosphoric acid-etched dentin. Scanning electron micrographs did not show a relationship between resin tags and bond strengths. CONCLUSION: There were incompatibilities between a self-cured core material and a dual-cured adhesive. All other combinations of core materials and adhesives produced strong in vitro bond strengths both in the self-etched and phosphoric acid-etched conditions.     

Microtensile bond strength of current dentin adhesives measured immediately and 24 hours after application

PURPOSE: To evaluate the immediate microtensile bond strengths achieved with representative adhesive systems from each of the four current bonding approaches. MATERIALS AND METHODS: Resin composite was bonded incrementally to flat, midcoronal dentin from 33 human molars, using the adhesives (Adper Scotchbond MP; Adper Scotchbond 1; Optibond Solo Plus; Clearfil SE Bond; AdheSE; Tyrian SPE + One Step Plus; Optibond Solo Plus self-etching; One-Up Bond F; iBond; Adper Prompt L-Pop; Xeno III) according to the respective manufacturer's instructions. The bonded specimens were immediately sectioned into sticks and underwent microtensile bond testing either immediately or after 24 h. Data were analyzed with two-way ANOVA and LSD tests. RESULTS: No significant differences were found between immediate and 24-h bond strengths (p > 0.05). However, significant differences were observed among adhesives (p = 0.001). The all-in-one adhesive iBond showed statistically lower values when compared to all the other adhesives. Adper Prompt L-Pop, Xeno III, Tyrian SPE + One Step Plus and One-Up Bond F, all self-etching adhesives, were significantly weaker than AdheSE, Optibond Solo Plus, Adper Scotchbond 1, Optibond Solo Plus self-etching, Clearfil SE Bond, and Adper Scotchbond MP, which did not differ statistically from each other. CONCLUSION: Microtensile bond strengths of representative adhesive systems from the four categories of bonding agents were not equivalent, with the lowest values recorded for the one-step self-etching adhesives. There were no differences in the bond strengths when measured immediately and after 24 h.     

Effect of adhesive systems and surface treatment of methacrylate resin-based fiber posts on post-resin-dentin bonds

PURPOSE: To evaluate the effect of different fiber post surface treatments on bond strength. METHODS: Extracted endodontically-treated premolars were prepared for the cementation of a methacrylate resin-based fiber post (FRC Postec). The posts received one of the three surface pre-treatments: silane application; hydrofluoric acid-etching and silane application or no treatment. A light-cured composite was used with one of the three dentin adhesives for luting: Single Bond; Clearfil Photo Bond and Clearfil New Bond, followed by a light-cured composite core build-up. Specimens were serially sliced into 0.8 x 0.8 mm-thick beams and loaded in tension until failure. RESULTS: Significant differences in bond strengths were recorded among the dentin adhesives (P< 0.05). However, post pre-treatment did not affect the bonding efficacy of the adhesives except for Clearfil New Bond.     

Effect of water storage on the bonding effectiveness of 6 adhesives to Class I cavity dentin

Adhesive-dentin interfaces degrade with time. This study determined the effect water storage may have on the bonding effectiveness of adhesives to occlusal Class I cavity-bottom dentin. Six adhesives, all representing contemporary classes of adhesives, were applied: a 3-step (OptiBond FL, Kerr) and 2-step (Scotchbond 1*, 3M ESPE) etch-and-rinse adhesive, a 2-step (Clearfil SE, Kuraray) and 1-step (Adper prompt, 3M ESPE) self-etch adhesive and a 2-step (FujiBond LC, GC) and 1-step (Reactmer, Shofu) resin-modified glass-ionomer adhesive. Bonding effectiveness was assessed by microtensile bond strength testing (MTBS) and electron microscopy (Feg-SEM and TEM). The MTBS was determined after 1 day and 1 year water storage of the entire restored cavity (indirect exposure of the adhesive-dentin interface to water) and prepared microTBS-beams (direct exposure of the adhesive-dentin interface to water). The hypotheses tested were: (1) resin-dentin bonds formed at the bottom of Class I cavities resist 1-year water storage and (2) an adjacent composite-enamel bond protects the composite-dentin bond against degradation. Non-parametric Kruskal-Wallis analysis statistically analyzed the microTBSs. The first hypothesis was rejected, as only the microTBS of OptiBond FL and Clearfil SE did not significantly decrease after 1-year direct and/or indirect water storage. The second hypothesis was corroborated, as the bonding effectiveness of most simplified adhesives (Scotchbond 1, Adper Prompt, FujiBond LC and Reactmer) approached 0 (because of the frequent pre-testing failures) after 1-year direct water exposure. The second hypothesis concluded that the 3-step etch-and-rinse adhesive must still be regarded the "gold standard." Though microTBS decreased significantly, Clearfil SE, as a 2-step self-etch adhesive, was the only simplified adhesive to perform reliably after 1-year direct water exposure.     

Micro-tensile and micro-shear bond strengths of current self-etch adhesives to enamel and dentin

PURPOSE: To evaluate the micro-tensile and micro-shear bond strengths of self-etch adhesives to enamel and dentin. METHODS: Extracted human molars were ground to expose flat enamel or dentin surfaces using wet #600 grit SiC paper. The enamel and dentin surfaces were assigned to four groups of four adhesives: three one-step self-etch adhesives (Clearfil S3 Bond; AQ Bond Plus, G-Bond) and a two-step self-etch adhesive (Clearfil SE Bond). Each of the adhesives were applied to the enamel or dentin surfaces in accordance with the manufacturers' instructions and restored with resin composite (Clearfil AP-X). The bonded teeth were then prepared for either micro-tensile or micro-shear bond strength tests. After storage in saline at 37 degrees C for 24 hours, specimens were stressed at a crosshead speed of 1 mm/minute. Mean bond strengths and modes of failure were analyzed using one-way ANOVA followed by Scheffe's F test and the Chi-square test, respectively, at a 95% level of confidence. RESULTS: SE Bond produced significantly higher values than the one-step adhesives in the micro-shear bond test to enamel (P< 0.05), while no significant differences were found among the adhesives in the micro-tensile bond test (P> 0.05). For dentin, SE Bond showed the highest bond strengths in both micro-tensile and micro-shear bond tests; values were significantly higher than both AQ Bond Plus and G-Bond (P< 0.05).     

Shear bond strengths of self-etching adhesives to caries-affected dentin on the gingival wall

The purpose of this study was to evaluate the bonding ability of five current self-etching adhesives to caries-affected dentin on the gingival wall. Seventy extracted human molars with approximal dentin caries were employed in this study. In order to obtain caries-affected dentin on the gingival wall, grinding was performed under running water. Following which, specimens mounted in acrylic blocks and composite resins of the bonding systems were bonded to dentin with plastic rings and then debonded by shear bond strength. With Clearfil SE Bond, bonding to caries-affected dentin showed the highest bond strength. With Optibond Solo Plus Self-Etch, bonding to caries-affected dentin showed higher shear bond strength than AQ Bond, Tyrian SPE & One-Step Plus, and Prompt-L-Pop (p<0.05). Further, the bond strengths of Clearfil SE Bond and Optibond Solo Plus Self-Etch to sound dentin were higher than those of Prompt-L-Pop, AQ Bond, and Tyrian SPE & One-Step Plus (p<0.05). In conclusion, besides micromechanical interlocking through hybrid layer formation, bond strength of self-etch adhesives to dentin may be increased from additional chemical interaction between the functional monomer and residual hydroxyapatite. The results of this study confirmed that differences in bond strength among self-etching adhesives to both caries-affected and sound dentin were due to chemical composition rather than acidity.     

Effective bond strength of current adhesive systems on deciduous and permanent dentin

PURPOSE: To evaluate the bond strength of a total-etching, self-priming system (Single Bond) and a self-etching system (Clearfil SE Bond) to deciduous and permanent human dentin. METHODS AND MATERIALS: Buccal dentin discs were prepared with a diamond disc from permanent first premolars, permanent third molars and deciduous second molars. The flat dentin surfaces were obtained by polishing with wet 600 grit silicon carbide papers. The specimens of each group were further divided into two groups for bonding to either Single Bond or Clearfil SE Bond. After 24 hours, the microshear bond strength testing was executed on a universal testing machine. Statistical analysis was performed at alpha = 0.05. RESULTS: No significant differences in bond strength were found between materials. However, deciduous dentin demonstrated significantly lower bond strengths than permanent premolar dentin when Single Bond was applied (p < 0.05). CONCLUSION: The difference in bonding substrate (permanent or deciduous dentin) had a significant effect on bond strength when the total-etching, self-priming system was applied.     

In vitro bonding performance of all-in-one adhesives. Part I--microtensile bond strengths

PURPOSE: The objective of this project was to compare the microtensile bond strengths (microTBS) of five "all-in-one" adhesives using two 2-step adhesives as controls. MATERIALS AND METHODS: Eighty-four extracted human molars were randomly assigned to one of three substrates: dentin, unground enamel, or ground enamel. For each substrate, specimens were randomly assigned to one of five all-in-one adhesives: (1) Adper Prompt L-Pop (AP, 3M ESPE); (2) Clearfil S3 Bond (S3, Kuraray); (3) G-Bond (GB, GC America) (4) iBond (iB, Heraeus Kulzer); (5) Xeno IV (XE, Dentsply Caulk). Adper Single Bond Plus (SB, 3M ESPE) was used as a two-step etch-and-rinse control, while Clearfil SE Bond (SE, Kuraray) was used as a two-step self-etching control. Crowns were built with Filtek Z250 (3M ESPE) and sectioned in x and y directions. The resulting sticks were fractured in tension at a crosshead speed of 1 mm/min. Statistical analysis was computed for each substrate with one-way ANOVA and Duncan's post-hoc test at p < 0.05. RESULTS: Means+/-SD are given in MPa; pretesting failures are shown in brackets. Dentin--SE: 79.1+/-20.5, [0/85]; SB: 76.3+/-19.3, [0/82]; AP: 51.6+/-21.9, [0/90]; XE: 40.5+/-22.9, [7/81]; S3: 27.8+/-13.2, [7/91]; iB: 17.4+/-15.6, [25/91]; GB: 11.7+/-7.4, [5/92]. Unground enamel--SB: 33.1+/-10.5, [0/69]; AP: 27.6+/-7.5, [0/66]; S3: 24.6 +/-12.0, [0/70]; SE: 16.8+/-11.7, [3/60]; XE 15.4+/-14.1, [16/63]; iB: 11.2+/-11.5, [18/64]; GB: 9.5+/-12.4, [31/63]. Ground enamel--SB: 33.7+/-9.1, [0/69]; AP: 33.2+/-7.9, [0/77]; SE: 26.4+/-9.5, [0/67]; S3: 25.5+/-8.9; [0/56]; XE: 21.0 +/-8.9, [3/68]; GB: 18.2+/-10.3, [4/68]; iB: 12.3+/-8.9, [11/52]. For dentin, the Duncan's test ranked the means in 6 statistical subsets: GB 相似文献   

Bond strength of adhesives to dentin involving total and self-etch adhesives.

OBJECTIVE: Currently, the trend in dentin adhesion seems to be shifting from moist bonding systems to self-etching systems and from several application steps to single steps. However, recent studies have indicated that the performance of single-step adhesives was lower than the 2-step self-etch or total etch systems. In the present study, microtensile bond strength of a total etch, 2-step self-etch and single-step self-etch adhesives was comparatively evaluated. METHOD AND MATERIALS: The superficial occlusal dentin of 12 noncarious extracted human molars was exposed, finished with wet 600-grit silicon carbide paper, and a block of resin composite bonded with adhesives according to the manufacturers' instructions. The teeth were kept in tap water for 24 hours at 37 degrees C and sectioned to produce beams, with adhesive areas of +/- 0.9 mm2 (4 beams per tooth were obtained). The specimens were stressed at a crosshead speed of 1 mm per minute until the bonds ruptured. RESULTS: The mean bond strengths were calculated as MPa and compared by performing analysis of variance and Tukey tests to identify significant differences between the materials (P = 0.05). The mean bond strength of Clearfil SE Bond was significantly higher than that of OptiBond Solo Plus and iBond (P <.05). OptiBond Solo Plus gave significantly higher bond strengths than iBond (P <.05). CONCLUSIONS: The self-etching adhesive system Clearfil SE Bond (2 step) had higher bond strength than the 1-bottle self-etching adhesive iBond (single application) and the 2-step single-bottle system OptiBond Solo Plus (total etch). However, the 1-bottle adhesive system OptiBond Solo Plus (total etch system) had higher bond strength than the 1-bottle self-etching adhesive system iBond.     

Effect of dentin conditioning on dentin permeability and micro-shear bond strength

The purpose of this study was to compare fluid flow rates across dentin surfaces treated with four conditioners. The effect of conditioning on the micro-shear bond strengths of glass ionomer cement (Fuji IX GP) and resin-based adhesives (Single Bond 2 or Clearfil SE Bond) were also investigated. Under a simulated pressure of 1.3 kPa, two dentin conditioners, phosphoric acid, and a self-etching primer were applied to the dentin surfaces. Dentinal fluid flows at baseline and after conditioning were recorded for 15 min each. The conditioned surfaces were examined using a scanning electron microscope. The micro-shear bond strengths of the glass ionomer cement and of the resin-based adhesives bonded to conditioned dentin surfaces were evaluated while simulated intrapulpal pressure was maintained at 0 or 1.3 kPa. Only the dentin surface etched with phosphoric acid showed a significant increase in permeability. Micro-shear bond strengths of Fuji IX GP were not affected by conditioning the dentin surfaces or by bonding at different intrapulpal pressures (0 or 1.3 kPa). The effects on bond strengths of resin-based adhesives depended on the system used. The simulated positive intrapulpal pressure during bonding significantly affected the adherence of Single Bond 2, whereas Clearfil SE Bond was unaffected.     

Effect of simulated pulpal pressure on dentin permeability and adhesion of self-etch adhesives.

OBJECTIVES: Dentin bonds made with one-bottle etch-and-rinse and self-etch adhesives are affected by the formation of interfacial blisters, porosities and deterioration. The first objective of this study was to evaluate the fluid flow through resin-dentin interfaces created by self-etching adhesives applied to deep dentin using a replica technique and by directly measuring dentin permeability (P). The second objective was to examine the effect of intrapulpal pressure on the microtensile bond strength of these adhesives. METHODS: A fluid-transport model was used to measure the fluid permeability (%P) through different adhesives. Impressions of bonded dentin were taken with a polyvinylsiloxane impression material to monitor fluid transudation from the surface of the adhesive. Positive replicas were fabricated for SEM examination. Two groups of resin-bonded specimens (pulpal pressure versus no pulpal pressure) were created for microtensile bond strength evaluation. Adhesive application was performed under 0 cm H(2)O. Pulpal pressure group was submitted to 20 cm H(2)O of pulpal pressure during build-up procedures. RESULTS: Clearfil Protect Bond exhibited the lowest permeability and fewest numbers of fluid droplets over the surface of the bonded dentin. G-Bond and Clearfil-S3 Bond were more permeable than Clearfil Protect Bond. One Up Bond F was the most permeable adhesive. A highly significant correlation was observed between the relative permeability of these adhesives (%P) and the number of fluid droplets on the adhesive surfaces. The application of pulpal pressure significantly reduced bond strength. SIGNIFICANCE: Resin-dentin bonds created by contemporary self-etch adhesives are susceptible to fluid permeation induced by pulpal pressure. HEMA-based adhesives showed the largest reductions in bond strengths after pulpal pressure application.     

Shear bond strength of seventh generation bonding agents on dentin of primary teeth--an in vitro study

This controlled, randomized, in vitro study evaluated the shear bond strength of several seventh generation bonding agents on the dentin of primary teeth. Six different adhesives were used: Xeno IV, Clearfil S3 Bond, Adper Prompt-L-Pop, AdheSE One, Bond Force, and Optibond (control). Ninety primary teeth were prepared by wet grinding with a 320-grit silicon carbide paper on a polishing wheel running at 110 RPM. After 24 hours of storage in water, shear bond strengths of each group were determined. The mean shear bond strength of the tested adhesive systems to primary dentin was 12.27 MPa. One-way ANOVA testing showed a statistically significant difference between adhesive products (P < 0.001). Tukey HSD post hoc tests were used to assess which means were significantly different from one another. There was no statistically significant difference between the fifth generation adhesive system (Optibond) and the two seventh generation systems (Xeno IV and Bond Force), with Optibond exhibiting a lower mean shear bond strength compared to Bond Force. Within the limitations of this study, there is a significant difference between seventh generation bonding materials. Bond Force and Optibond appear to exhibit higher shear bond strengths than the other products.     

Resistance of ten contemporary adhesives to resin-dentine bond degradation

OBJECTIVES: To evaluate resin-dentine bond degradation after 1 year of water storage. METHODS: Human dentine surfaces were bonded with two etch-and-rinse self-priming adhesives (Single Bond/SB and Prime & Bond NT/PBNT), three 2-step self-etching adhesives (Clearfil SE Bond/SEB, Resulcin Aqua Prime/RES and Non-Rinse Conditioner with Prime & Bond NT/NRC-PBNT), and five 1-step self-etching adhesives (Etch & Prime 3.0/EP, Prompt L-Pop/PLP, Solist/SOL, Futurabond/FUT and AQ Bond/AQ). Adhesives were applied according to manufacturers' instructions. Composite build-ups were constructed and the bonded teeth were stored (24 h, 6 months, 1 year) in distilled water at 37 degrees C. After storage, the intact teeth were sectioned into beams and all specimens were tested for microtensile bond strengths (MTBS). ANOVA and multiple comparisons tests were applied at alpha = 0.05. Fractographic analysis of debonded beams was performed using scanning electron microscopy. RESULTS: SB, PBNT and SEB attained the highest MTBS, regardless of the storage period. A significant decrease in MTBS was observed after 6 months for SOL. After 12 months the only groups that did not reduce bond strength were SB and SEB. Bonded specimens in NRC-PBNT, RES and FUT produced pre-testing failures after 12 months, and MTBS could not be measured. CONCLUSIONS: The resistance of resin-dentine bonds to degradation is material-dependent. When the enamel-resin interface is preserved, the etch-and-rinse adhesives and the mild 2-step self-etch adhesive SEB exhibited the best resin-dentine bond durability. Those tested self-etching adhesives having a pH < or 1 and using water or acetone as solvent attained catastrophic bond failure after 1 year of water storage.     

Bond strengths of three different dentin adhesive systems to sclerotic dentin

The two-fold aims of this study were: (1) to evaluate the microtensile bond strengths of different adhesive systems to sclerotic and sound palatal dentin; and (2) to observe the respective resin-dentin interfaces. Thirty extracted human incisor teeth were divided into two groups. Group I comprised sclerotic defects in the palatal zone. Group II comprised sound palatal dentin surfaces as control. Each group (n=15) was divided into three subgroups according to dentin adhesive systems: self-etch (Clearfil SE Bond), total-etch (Scotchbond Multi-Purpose Plus), and glass ionomer (Reactmer Bond) adhesive systems. The specimens were subjected to tensile forces. Obtained data were analyzed by two-way ANOVA and post hoc Duncan's test. Fracture sites and resin-dentin interfaces were observed using a light microscope and SEM. With sound dentin, Clearfil SE Bond showed a significantly higher bond strength than the other adhesives (p < 0.05). With sclerotic dentin, although there were no significant differences in bond strength among the adhesives groups (p > 0.05), the bond strength values of Clearfil SE Bond and Scotchbond Multi-Purpose Plus were significantly decreased. On resin-dentin interface observation, different images were presented by different bonding systems.