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Objective: The purpose of this study was to determine the influence of different smear layers on enamel and dentin bond durability of various types of self-etch adhesives., Methods: Two universal adhesives, Scotchbond Universal (SU) and Prime & Bond elect (PE); a conventional single-step self-etch adhesive, G-ænial Bond (GB); and two two-step self-etch adhesives, Optibond XTR (OX) and Clearfil SE Bond (SE) were used in this study. Shear bond strengths (SBS) and shear fatigue strengths (SFS) to human enamel and dentin were determined with different smear layer conditions. The prepared specimens were divided into three groups. The bonding surfaces were prepared by grinding with either (1) #180, (2) #600, or (3) #4000-SiC papers before making the bonded assemblies. For each group, 15 specimens were prepared for the SBS and 30 specimens for the SFS., Results: The two-step self-etch adhesives showed significantly higher SFS values than the single-step self-etch adhesives, regardless of the smear layer condition or substrate. Although most of the tested adhesives showed no significant differences in enamel SFS values among the smear layer groups, SU, GB, and SE showed significantly lower SFS values in the #180 in dentin groups than the #600 and #4000 groups., Conclusion: The influence of different smear layer conditions on bond durability was adhesive dependent. Furthermore, the smear layers generated on different substrates also influenced the bond quality of the self-etch adhesives., Significance: Smear layer conditions of enamel and dentin influence the bond durability of universal adhesives and conventional single and two-step self-etch adhesives., (Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.)

Objectives: The purpose of this study was to determine the influence of different frequency rates on of bond durability of self-etch adhesives to enamel using shear fatigue strength (SFS) testing., Methods: A two-step self-etch adhesive (OX, OptiBond XTR), and two single step self-etch adhesives (GB, G-ӕnial Bond and SU, Scotchbond Universal) were used in this study. The shear fatigue strength (SFS) to enamel was obtained. A staircase method was used to determine the SFS values with 50,000 cycles or until failure occurred. Fatigue testing was performed at frequencies of 5Hz, 10Hz, and 20Hz. For each test condition, 30 specimens were prepared for the SFS testing., Results: Regardless of the bond strength test method, OX showed significantly higher SFS values than the two single-step self-etch adhesives. For each of the three individual self-etch adhesives, there was no significant difference in SFS depending on the frequency rate, although 20Hz results tended to be higher., Conclusions: Regardless of the self-etch adhesive system, frequencies of 5Hz, 10Hz, and 20Hz produced similar results in fatigue strength of resin composite bonded to enamel using 50,000 cycles or until bond failure., Significance: Accelerated fatigue testing provides valuable information regarding the long term durability of resin composite to enamel bonding using self-etch adhesive system., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Purpose: To use shear bond strength (SBS) and shear fatigue strength (SFS) testing to determine the influence of phosphoric acid pre-etching times prior to application of self-etch adhesives on enamel bonding., Materials and Methods: Two single-step self-etch universal adhesives (Prime&Bond Elect and Scotchbond Universal), a conventional single-step self-etch adhesive (G-ӕnial Bond), and a conventional two-step self-etch adhesive (OptiBond XTR) were used. The SBS and SFS were obtained with phosphoric acid pre-etching for 3, 10, or 15 s prior to application of the adhesives, and without pre-etching (0 s) as a control. A staircase method was used to determine the SFS with 10 Hz frequency for 50,000 cycles or until failure occurred. The mean demineralization depth for each treated enamel surface was also measured using a profilometer., Results: For all the adhesives, the groups with pre-etching showed significantly higher SBS and SFS than groups without pre-etching. However, there was no significant difference in SBS and SFS among groups with > 3 s of preetching. In addition, although the groups with pre-etching showed significantly deeper demineralization depths than groups without pre-etching, there was no significant difference in depth among groups with > 3 s of pre-etching., Conclusion: Three seconds of phosphoric acid pre-etching prior to application of self-etch adhesive can enhance enamel bonding effectiveness.

Objectives: The purpose of this study was to determine enamel and dentin bond durability after long-term water storage using self-etch adhesives., Methods: Two single step self-etch adhesives (SU, Scotchbond Universal and GB, G-ӕnial Bond) and a two-step self-etch adhesive (OX, OptiBond XTR) were used. The shear bond strength (SBS) and shear fatigue strength (FS) of the enamel and dentin were obtained with and without phosphoric acid pre-etching prior to application of the adhesives. The specimens were stored in distilled water at 37 °C for 24 h, 6 months, and one year. A staircase method was used to determine the FS using a frequency of 10 Hz for 50,000 cycles or until failure occurred., Results: The SBS and FS of enamel bonds were significantly higher with pre-etching, when compared to no pre-etching for the same water storage period. The FS of dentin bonds with pre-etching tended to decrease relative to no pre-etching at the same storage period. For the one year storage period, SU and GB with pre-etching showed significantly lower FS values than the groups without pre-etching., Conclusions: The influence of water storage on FS of the self-etch adhesives was dependent on the adhesive material, storage period and phosphoric acid pre-etching of the bonding site., Clinical Significance: Phosphoric acid pre-etching of enamel improves the effectiveness of self-etch adhesive systems. Inadvertent contact of phosphoric acid on dentin appears to reduce the ability of self-etch adhesives to effectively bond resin composite materials., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

This study examined the effect of different enamel and dentin conditioning times on the shear bond strength of a resin composite using etch-and-rinse and self-etch adhesive systems. Shear bond strengths were determined following treatment of flat ground human enamel and dentin surfaces (4000 grit) with 11 adhesive systems: 1) AdheSE One Viva Pen-(ASE), 2) Adper Prompt L-Pop-(PLP), 3) Adper Single Bond Plus-(SBP), 4) Clearfil SE Bond-(CSE), 5) Clearfil S3 Bond-(CS3), 6) OptiBond All-In-One-(OBA), 7) OptiBond Solo Plus-(OBS), 8) Peak SE-(PSE), 9) Xeno IV-(X4), 10) Xeno V-(X5) and 11) XP Bond-(XPB) using recommended treatment times and an extended treatment time of 60 seconds (n = 10/group). Composite (Z100) to enamel and dentin bond strengths (24 hours) were determined using Ultradent fixtures and debonded with a crosshead speed of 1 mm/minute. The data were analyzed with a three-way Analysis of Variance (ANOVA) and Fisher's LSD post hoc test. The highest shear bond strengths (MPa) to enamel were achieved by the three etch-and-rinse systems at both the recommended treatment time (SBP-40.5 +/- 6.1; XPB-38.7 +/- 3.7; OBS- 35.2 +/- 6.2) and the extended treatment time (SBP-44.5 +/- 8.1; XPB-40.9 +/- 5.7; OBS-35.0 +/- 4.5). Extending the enamel treatment time did not produce a significant change (p > 0.05) in bond strength for the 11 adhesive systems tested. OBS generated the highest (46.2 +/- 7.9) bond strengths to dentin at the recommended treatment time. At the extended treatment time X4 (42.2 +/- 11.7), PSE (42.1 +/- 9.7) and OBS (41.4 +/- 8.0) produced the highest bond strengths to dentin. The bond strength change between recommend and extended treatment times was significant (p < 0.05) for PSE, but the other 10 systems did not exhibit any significant change.

Objective: Shear fatigue limit (SFL) testing, coupled with shear bond strength (SBS) measurements can provide valuable information regarding the ability of adhesive systems to bond to mineralized tooth structures. The clinical technique for enamel bonding with adhesive resins has shifted from bonding to a thoroughly dried acid conditioned surface to a moist surface to facilitate dentin bonding. The purpose of this study was to compare the performance of ethanol-containing etch-and-rinse adhesive (ERA) systems on moist and dry enamel by determining the resin composite to enamel SBS and SFL, and examining the relationship of SBS and SFL., Methods: Twelve specimens each were used to determine 24-h resin composite (Z100 - 3M ESPE) to enamel SBS to moist and dry surfaces with two ERA systems, Adper Single Bond Plus (SBP) and OptiBond Solo Plus (OBP). A staircase method of fatigue testing was used in a four-station fatigue cycler to determine the SFL of resin composite to enamel bonds (moist and dry) with the two ERA systems (20 specimens for each test condition) at 0.25Hz for 40,000 cycles. ANOVA and Tukey's post hoc test were used for the SBS data and a modified t-test with Bonferroni correction was used for comparisons of SFL., Results: The two ERA systems each generated statistically similar SBS (p>0.05) to moist and dry enamel and the SBS of SBP was significantly higher than OBP on dry enamel (p<0.05). The SFL of SBP was significantly greater to dry enamel when compared to moist enamel and there was not a significant difference in the SFL of OBP on dry and moist enamel. There were no significant differences in SFL values between SBP on either moist or dry enamel and OBP on both moist and dry enamel., Significance: Fatigue testing may provide more useful information than SBS tests regarding the performance of dental adhesive systems. The chemical composition, solvents and filler components of ERA systems may influence their ability to develop long-term durable bonds to both moist and dry enamel surfaces.

Objective: Etch and resin infiltration morphologies were compared for three self-etch adhesive (SEA) systems and eleven model etch-and-rinse (ERA) systems using various phosphoric acid (PA) concentrations with Adper Single Bond Plus (SB) adhesive. Matches for the morphologies were made between each SEA system and one of the PA/SB systems and bond strength measurements were made for all the systems. The hypothesis was that similar morphology would result in similar bond strength assuming micro-mechanical bonding is the mechanism of adhesion., Methods: Three specimens were prepared on polished (4000 grit) human enamel for each adhesive system to examine etch and resin infiltration morphology by SEM. For the latter, the adhesive systems were bonded using recommended methods and the enamel was dissolved in acid to reveal the resin. The etch patterns for the SEA systems were determined by rinsing off the material with water and acetone. Polished (4000 grit) human enamel was used with each adhesive system to determine 24-h resin composite to enamel shear bond strengths (SBS). A minimum of 10 specimens were used for each group. Data were analyzed by a one factor ANOVA and Fisher's PLSD post hoc test., Results: The SBS to polished enamel for two of the three SEA systems were statistically significantly greater (p<0.05) than the PA/SB matched systems, indicating that chemical bonding might be partly responsible for the measured bond strength. All three SEA systems provided statistically lower (p<0.05) SBS values than the PA/SB systems with PA concentrations between 2.5% and 40%., Significance: Although chemical bonding may be present for some SEA systems it does not provide enough increase in bond strength to compete with the bond produced by ERA systems using phosphoric acid etching of enamel.

Objective: Bond strengths of composite resin to enamel using four self-etch adhesive (SEA) systems were compared with the bond strength of an etch-and-rinse adhesive (ERA) system, for both polished enamel and enamel pre-etched with phosphoric acid. The objective was to determine if the pre-etching would increase the bond strengths of the SEA systems to match the ERA system., Methods: Ten specimens were used for each adhesive to determine 24-h resin composite to enamel shear bond strengths (SBS) to polished (4000 grit) human enamel and this was repeated for the SEA systems for enamel that was pre-etched with phosphoric acid for 15s. SEM analysis was made to assess the degree of etching and resin penetration into enamel for each of the adhesive systems. Data were analyzed by a two factor ANOVA with a Tukey HSD post hoc test., Results: The SBS to polished enamel for all four SEA systems were statistically significantly lower (p<0.05) than the ERA control, but with pre-etched enamel there were no statistically significant differences (p>0.05) between any of the adhesive systems. All four of the SEA systems demonstrated statistically significant increases in bond strength between bonding to polished and pre-etched enamel, ranging from 27% to 86%. The results of SEM analysis showed no differences in the resin penetration patterns of any of the adhesives for enamel that was etched with phosphoric acid., Significance: Pre-etching enamel may enhance the bond strength of SEA systems to values comparable with those found with ERA adhesive systems, which may improve their overall performance in clinical use.

Objective: Fatigue testing of adhesive bonds to tooth structures in conjunction with bond strength testing can provide more useful information for examining the effectiveness of dental adhesives. The purpose of this study was to determine the shear bond strength (SBS) and shear fatigue limit (SFL) of composite to enamel bonds using modern adhesive systems., Methods: Twelve specimens each were used to determine 24-h resin composite (Z100-3M ESPE) to enamel shear bond strengths with an etch-and-rinse system (ERA), Adper Single Bond Plus (SB), and four self-etch adhesives (SEA)--Adper Prompt-L-Pop (PLP), Clearfil SE (CSE), Clearfil S(3) (CS3) and Xeno IV (X4). A staircase method of fatigue testing was used in a four-station fatigue cycler to determine the SFL of composite to enamel bonds with the adhesives (16-20 specimens for each adhesive) at 0.25 Hz for 40,000 cycles. ANOVA and Tukey's post hoc test were used for the SBS data and a modified t-test with Bonferroni correction was used for comparisons of the SFL., Results: The SBS and SFL of the etch-and-rinse system were significantly greater (p<0.05) than those of the four self-etch adhesives. The SBS and SFL of CSE were also significantly greater than for the other three self-etch systems. The ratio of SFL to SBS was highest with the etch-and-rinse system and the ratio became increasing smaller in the same order that the values for SBS decreased with the self-etch systems., Significance: The lower fatigue limits for composite to enamel bonds obtained with the self-etch adhesive systems may indicate that greater enamel margin breakdown will occur with restorations where these systems are used for bonding.

The current study examined the effect of different enamel conditioning times on surface roughness and bond strength using an etch-and-rinse system and four self-etch adhesives. Surface roughness (Ra) and composite to enamel shear bond strengths (SBS) were determined following the treatment of flat ground human enamel (4000 grit) with five adhesive systems: (1) Adper Single Bond Plus (SBP), (2) Adper Prompt L-Pop (PLP), (3) Clearfil SE Bond (CSE), (4) Clearfil S3 Bond (CS3) and (5) Xeno IV (X4), using recommended treatment times and an extended treatment time of 60 seconds (n = 10/group). Control groups were also included for Ra (4000 grit surface) and SBS (no enamel treatment and Adper Scotchbond Multi-Purpose Adhesive). For surface roughness measurements, the phosphoric acid conditioner of the SBP etch-and-rinse system was rinsed from the surface with an air-water spray, and the other four self-etch adhesive agents were removed with alternating rinses of water and acetone. A Proscan 2000 non-contact profilometer was used to determine Ra values. Composite (Z100) to enamel bond strengths (24 hours) were determined using Ultradent fixtures and they were debonded with a crosshead speed of 1 mm/minute. The data were analyzed with ANOVA and Fisher's LSD post-hoc test. The etch-and- rinse system (SBP) produced the highest Ra (microm) and SBS (MPa) using both the recommended treatment time (0.352 +/- 0.028 microm and 40.5 +/- 6.1 MPa) and the extended treatment time (0.733 +/- 0.122 microm and 44.2 +/- 8.2 MPa). The Ra and SBS of the etch-and-rinse system were significantly greater (p < 0.05) than all the self-etch systems and controls. Increasing the treatment time with phosphoric acid (SBP) and PLP produced greater surface roughness (p < 0.05) but did not result in significantly higher bond strengths (p > 0.05).

Objective: Etching of enamel by self-etching adhesive systems is not as pronounced as with phosphoric acid employed with most total-etch adhesive systems. This may result in differences in the effectiveness of the bonds for the two types of systems. The aim of this study was to compare two such systems by bond strength and fatigue testing., Materials and Methods: Shear bond strengths for Single Bond (SB) and Adper Prompt-L-Pop (PLP) were obtained on bovine enamel surfaces. Fatigue measurements were made with the same test fixtures using cyclical loading at 2 Hz for a maximum of 10(5) cycles or until the bond failed. Four selected loads between 40 and 70% of the shear bond strength were tested for each adhesive and the number of cycles to failure was recorded. S-N curves were constructed from the data and fatigue stress limits were determined. The Mann-Whitney U-test and t-tests were used for statistical comparisons of the results. SEM analysis of resin tag formation into enamel surfaces was carried out., Results: A significantly greater bond strength was found for SB (25.3 MPa) than for PLP (19.2). Sustainable stresses after 10(5) load cycles were substantially lower than the corresponding shear bond strengths and fatigue limits were found to be 8.4 MPa for PLP and 14.6 MPa for SB. The ratio of fatigue limit to bond strength was less for PLP (44%) than for SB (57%). Resin tag penetration into enamel was substantially less for PLP than for SB., Significance: Fatigue testing in conjunction with bond strength testing can provide a better means for assessing the performance of adhesive systems used for bonding to enamel.

Objectives: The objective of this study was to evaluate the effect of various surface treatments on the bond strength of several glass ionomers to enamel, and to examine the resulting bond interface., Methods: Ground bovine enamel specimens were divided into groups which were pretreated with one of the following: (1) no pretreatment, (2) Vitremer primer, (3) 10% polyacrylic acid or (4) 35% phosphoric acid. A conventional glass ionomer and two resin-modified glass ionomers (RMGI's) were bonded to the pretreated enamel surfaces, stored in water for 24h and shear bond strengths measured. RMGI's were tested as light-cured and self-cured materials. Transverse sections of similarly prepared samples were etched with phosphoric acid for 60s to partially remove enamel and expose the enamel/glass-ionomer interface. The interface morphology was examined by SEM., Results: Polyacrylic acid and phosphoric acid conditioning resulted in significantly increased bond strength to enamel for all three glass ionomer materials, compared to no pretreatment (p<0.01). Light-cured bond strengths were in most cases, significantly greater than when self-cured (p<0.01). Examination of the bonded interfaces revealed the presence of polymer tags in the enamel conditioned with polyacrylic acid and phosphoric acid., Significance: Conditioners significantly improved the bond to enamel for the conventional glass ionomer and RMGI's that were examined in this study. Micromechanical bonding may play a role in the mechanism of bonding glass ionomer to enamel.

The purpose of this study was to determine the enamel bond durability of three universal adhesives in different etching modes through fatigue testing. The three universal adhesives used were Scotchbond Universal, Prime&Bond Elect universal dental adhesive, and All-Bond Universal light-cured dental adhesive. A single-step self-etch adhesive, Clearfil S3 Bond Plus was used as a control. The shear bond strength (SBS) and shear fatigue strength (SFS) to human enamel were evaluated in total-etch mode and self-etch mode. A stainless steel metal ring with an internal diameter of 2.4 mm was used to bond the resin composite to the flat-ground (4000-grit) tooth surfaces for determination of both SBS and SFS. For each enamel surface treatment, 15 specimens were prepared for SBS and 30 specimens for SFS. The staircase method for fatigue testing was then used to determine the SFS of the resin composite bonded to the enamel using 10-Hz frequencies for 50,000 cycles or until failure occurred. Scanning electron microscopy was used to observe representative debonded specimen surfaces and the resin-enamel interfaces. A two-way analysis of variance and the Tukey post hoc test were used for analysis of the SBS data, whereas a modified t-test with Bonferroni correction was used for the SFS data. All adhesives in total-etch mode showed significantly higher SBS and SFS values than those in self-etch mode. Although All-Bond Universal in self-etch mode showed a significantly lower SBS value than the other adhesives, there was no significant difference in SFS values among the adhesives in this mode. All adhesives showed higher SFS:SBS ratios in total-etch mode than in self-etch mode. With regard to the adhesive systems used in this study, universal adhesives showed higher enamel bond strengths in total-etch mode. Although the influence of different etching modes on the enamel-bonding performance of universal adhesives was found to be dependent on the adhesive material, total-etch mode effectively increased the enamel bond strength and durability, as measured by fatigue testing. [ABSTRACT FROM AUTHOR]

The present study aimed to determine the effect of the functional monomer, 10-methacryloxydecyl dihydrogen phosphate ( MDP), on the enamel bond durability of single-step self-etch adhesives through integrating fatigue testing and long-term water storage. An MDP-containing self-etch adhesive, Clearfil Bond SE ONE ( SE), and an experimental adhesive, MDP-free ( MF), which comprised the same ingredients as SE apart from MDP, were used. Shear bond strength ( SBS) and shear fatigue strength ( SFS) were measured with or without phosphoric acid pre-etching. The specimens were stored in distilled water for 24 h, 6 months, or 1 yr. Although similar SBS and SFS values were obtained for SE with pre-etching and for MF after 24 h of storage in distilled water, SE with pre-etching showed higher SBS and SFS values than MF after storage in water for 6 months or 1 yr. Regardless of the pre-etching procedure, SE showed higher SBS and SFS values after 6 months of storage in distilled water than after 24 h or 1 yr. To conclude, MDP might play an important role in enhancing not only bond strength but also bond durability with respect to repeated subcritical loading after long-term water storage. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To examine the reduction in enamel demineralization provided by fluoride release from a conventional glass-ionomer, a resin-modified glass-ionomer and an experimental fluoride-releasing resin-based composite compared To a conventional resin-based composite control, and to correlate the level of fluoride release with demineralization. Materials and Methods: Enamel surfaces of extracted human incisors had a 0.4 mm thick layer of the specified test material carefully placed in a band across the mid-facial enamel to simulate a cement layer beneath an orthodontic bracket. The top surface of the test material was covered with nail varnish, leaving only the edges of the material exposed to release fluoride. The teeth were additionally covered with nail varnish to within 1 mm of the test material. Each group of teeth was placed into separate volumes of unstirred demineralizing solution at a pH of 4.7 for 4 days. The specimens were sectioned and examined by polarized light microscopy. Lesion areas were measured at distances from 100-300 µm away from the test material. Fluoride release for the test materials was measured for periods up to 5 months. Results: All of the fluoride-releasing materials demonstrated a statistically significant (P< 0.05) degree of protection of enamel from demineralization compared to the non-fluoride control material. The degree of protection was greatest near the material, but lesion areas increased with distance in an inverse relationship to the amount of fluoride release. Lesions were displaced from the region near the materials and the mean displacement was directly related to amount of fluoride release. The mean lesion areas for each distance decreased with the logarithm of the cumulative fluoride release. [ABSTRACT FROM AUTHOR]