OptiBond XTR Research Articles

Shear fatigue strength of resin composite bonded to dentin at physiological frequency.

The purpose of this study was to examine the shear fatigue strengths of a resin composite bonded to dentin. Three adhesive systems - a two-step self-etch adhesive (OptiBond XTR; Kerr) and two universal adhesives [Scotchbond Universal (3M ESPE) and G-Premio Bond (GC)] - were used in self-etch mode to bond a resin composite to dentin at a physiologic frequency of 2 Hz over 50,000, 100,000, and 1,000,000 cycles. A staircase method of fatigue testing was used. Twenty specimens were used for each test condition. There was no significant difference in shear fatigue strength across the cycling periods for the three individual adhesives. Differences in shear fatigue strength were found among the three adhesives within each cycling period. Regardless of the adhesive used in self-etch mode for bonding a resin composite to dentin, shear fatigue strength was not influenced by the number of cycles used for testing.

Does acid-etching jeopardize dentin bonding durability?

Purpose: The purpose of the study was to evaluate the impact of the etching process on the durability of normal versus sclerotic dentin bonded interfaces.Materials & Methods: Micro-tensile bond strengths and interfacial nanoleakage, within bonded normal or sclerotic dentin interfaces created by Adper Single Bond 2, Optibond XTR, Single Bond Universal, Ketac Molar (glass ionomer) or Photac Fil (resin-modified glass ionomer), were evaluated after 24 h, 6 m and 12 m of water storage. Results: Adper Single Bond 2, Optibond XTR and Single Bond Universal exhibited higher immediate bond strengths and nanoleakage than did Ketac Molar or Photac fil. Normal dentin exhibited higher immediate bond strength and lower immediate nanoleakage when compared to sclerotic dentin, using Adper Single Bond 2, Optibond XTR and Single Bond Universal. Twelve months of water storage resulted in a significant decrease in micro-tensile bond strength in both normal and sclerotic dentin bonded by these three adhesives. However, there was no significance difference between the bond strengths and nanoleakage created by Ketac Molar and Photac Fil, used with normal or sclerotic dentin at the three storage periods. Conclusion: Compared to resin-based etching restoratives, mineral-based non-etching restoratives (Ketac Molar and Photac Fil) provided much more durable bonds, to both normal and sclerotic dentin, over a period of 12 months. It is obvious that the acid-etching procedure is the main cause of instability of resin-dentin bonded interfaces. Sclerotic dentin did not act as a bonding impediment with mineral-based non-etching restoratives as it did with resin-based etching adhesives. Clinical Significance: Although recently introduced adhesive resins have attempted to improve resin-dentin bond durability, biodegradation of resin-dentin bonds over time continues to jeopardize the durability of resin composite restorations.

GPDM- and 10-MDP-based Self-etch Adhesives Bonded to Bur-cut and Uncut Enamel - "Immediate" and "Aged" µTBS.

To determine the microtensile bond strength (µTBS) of two 2-step self-etch adhesives (SEAs) to bur-cut and uncut enamel. The buccal and lingual enamel surfaces of 15 teeth were ground flat ("bur-cut" enamel), while the enamel surface of another set of 15 teeth was solely prophylactically cleaned ("uncut" enamel). Resin composite was bonded to the surfaces using the GPDM-based SEA OptiBond XTR (Kerr), the 10-MDP-based SEA Clearfil SE Bond (Kuraray Noritake), or the 3-step etch-and-rinse adhesive (E&RA) OptiBond FL (Kerr) that served as the gold-standard control. After 1-week water storage at 37°C, specimens were serially cut into 1-mm2 stick-shaped microspecimens, of which half per tooth were further subjected to 20,000 thermocycles (TC) prior to µTBS testing. Data were statistically analyzed using ANOVA and the post-hoc Tukey test. The interfacial ultrastructure of the GPDM-based SEA OptiBond XTR with uncut and bur-cut enamel was additionally characterized with transmission electron microscopy (TEM). After 1-week water storage and upon TC aging, both SEAs bonded significantly (p < 0.05) less effectively to both bur-cut and uncut enamel than did the control OptiBond FL, except when OptiBond XTR was bonded to bur-cut enamel; then a similarly high µTBS was recorded (p > 0.05). TEM interfacial characterization revealed a tight interaction of Optibond XTR with both bur-cut and uncut enamel. The best bonding efficacy to enamel is still achieved by etching with phosphoric acid, following an E&R approach, while the higher etching efficacy of the GPDM-based SEA may result in equally effective bonding, provided that the enamel is bur-roughened first.

Influence of different smear layers on bond durability of self-etch adhesives

ObjectiveThe 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. MethodsTwo 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. ResultsThe 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. ConclusionThe 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. SignificanceSmear layer conditions of enamel and dentin influence the bond durability of universal adhesives and conventional single and two-step self-etch adhesives.

Effect of double-layer application on bond quality of adhesive systems.

The aim of this study was to determine the effect of double-layer application of universal adhesives on the bond quality and compare to other adhesive systems. Two universal adhesives used were in this study: Scotchbond Universal (SU), [3M ESPE] and Prime & Bond elect (PE), [Dentsply Caulk]. The conventional single-step self-etch adhesives G-ӕnial Bond (GB), [GC Corporation.] and BeautiBond (BB), [Shofu Inc.], and a two-step self-etch adhesive, Optibond XTR (OX), [Kerr Corporation], were used as comparison adhesives. Shear bond strengths (SBS) and shear fatigue strengths (SFS) to human enamel and dentin were measured in single application mode and double application mode. For each test condition, 15 specimens were prepared for SBS testing and 30 specimens for SFS testing. Enamel and dentin SBS of the universal adhesives in the double application mode were significantly higher than those of the single application mode. In addition, the universal adhesives in the double application mode had significantly higher dentin SFS values than those of the single application mode. The two-step self-etch adhesive OX tended to have lower bond strengths in the double application mode, regardless of the test method or adherent substrate. The double application mode is effective in enhancing SBS and SFS of universal adhesives, but not conventional two-step self-etch adhesives. These results suggest that, although the double application mode may enhance the bonding quality of a universal adhesive, it may be counter-productive for two-step self-etch adhesives in clinical use.

Simplified cementation of lithium disilicate crowns: Retention with various adhesive resin cement combinations

Statement of problemA composite resin cement and matching self-etch adhesive was developed to simplify the dependable retention of lithium disilicate crowns. The efficacy of this new system is unknown. PurposeThe purpose of this in vitro study was to determine whether lithium disilicate crowns cemented with a new composite resin and adhesive system and 2 other popular systems provide clinically acceptable crown retention after long-term aging with monthly thermocycling. Material and methodsExtracted human molars were prepared with a flat occlusal surface, 20-degree convergence, and 4 mm axial length. The axio-occlusal line angle was slightly rounded. The preparation surface area was determined by optical scanning and the analysis of the standard tessellation language (STL) files. The specimens were distributed into 3 cement groups (n=12) to obtain equal mean surface areas. Lithium disilicate crowns (IPS e.max Press) were fabricated for each preparation, etched with 9.5% hydrofluoric acid for 15 seconds, and cleaned. Cement systems were RelyX Ultimate with Scotch Bond Universal (3M Dental Products); Monobond S, Multilink Automix with Multilink Primer A and B (Ivoclar Vivadent AG); and NX3 Nexus with OptiBond XTR (Kerr Corp). Each adhesive provided self-etching of the dentin. Before cementation, the prepared specimens were stored in 35°C water. A force of 196 N was used to cement the crowns, and the specimens were polymerized in a 35°C oven at 100% humidity. After 24 hours of storage at 100% humidity, the cemented crowns were thermocycled (5°C to 55°C) for 5000 cycles each month for 6 months. The crowns were removed axially at 0.5 mm/min. The removal force was recorded and the dislodgement stress calculated using the preparation surface area. The type of cement failure was recorded, and the data were analyzed by 1-way ANOVA and the chi-square test (α=.05) after the equality of variances had been assessed with the Levene test. ResultsThe Levene test was nonsignificant (P=.936). The ANOVA revealed the mean removal stresses, and forces did not differ for RelyX Ultimate with Scotchbond Universal (3.9 MPa; 522 N) and Multilink Automix with Multilink Primer (3.7 MPa; 511 N); both differed significantly (P=.022) from the mean for NX3 Nexus with OptiBond XTR (2.9 MPa; 387 N). For all 3 cements, the modes of failure showed cement principally on the crown intaglio, and the chi-square analysis was nonsignificant (P=.601). ConclusionsIPS e.max Press (lithium disilicate) crowns were well retained (2.9-3.9 MPa; 387-522 N) by the 3 cement-adhesive combinations after 6 months of aging with monthly thermocycling. These results can serve as a basis for cement selection for this type of crown because the values significantly exceeded those for zinc phosphate. Cements using their matched dentin bonding agent as the ceramic primer were as successful as cements with a separate silane coupling agent.

Effect of universal adhesive etching modes on bond strength to dual-polymerizing composite resins

Statement of problemInformation is lacking as to the effect on bond strength of the etching modes of universal adhesives when they are used to bond dual-polymerizing composite resins to dentin. PurposeThe purpose of this in vitro study was to investigate the bonding of dual-polymerizing foundation composite resins to dentin when universal bonding agents are used in self-etch or etch-and-rinse modes. Material and methodsSixty caries-free, extracted third molar teeth were sectioned transversely in the apical third of the crown and allocated to 12 groups (n=5). Three different bonding agents (Scotchbond Universal, OptiBond XTR, All-Bond Universal) were used to bond 2 different dual-polymerizing composite resins (CompCore AF or CoreFlo DC) to dentin, using 2 different etching approaches (etch-and-rinse or self-etch). The specimens were sectioned into sticks (1×1×8 mm) with a precision saw. The bond strength of the specimens was tested under microtensile force at a crosshead speed of 0.5 mm/min. The data were analyzed using a 3-way ANOVA, a Games-Howell post hoc comparisons model, and Student t tests with Bonferroni corrections (α=.05). ResultsIn the overall model, the composite resin used had no effect on bond strength (P=.830). The etching protocol by itself also did not have a significant effect (P=.059), although a trend was present. The bonding agent, however, did have an effect (P<.001) on bond strength. Also, a significant interaction effect was found for the bonding agent and etching protocol on bond strength (P<.001). The etching protocol influenced the bond strength when Scotchbond Universal (P<.008) and All-Bond Universal (P<.004) were used but not when OptiBond XTR was used (P=1.00). A self-etch protocol provided significantly higher bond strength when Scotchbond Universal was used, whereas with All-Bond Universal, an etch-and-rinse protocol, provided higher bond strength. ConclusionsWhen universal bonding agents were used to secure dual-polymerizing composite resins to dentin, no single etching protocol is better than another. Depending on which bonding agent is being used, one etching mode may perform better.

Microtensile Bond Strength of Adhesive Systems in Different Dentin Regions on a Class II Cavity Configuration.

The aim of this study was to evaluate microtensile bond strength (µTBS) of self-etch and etch-and-rinse adhesives systems compared in different dentin regions (central-CD or proximal-PD) in a class II cavity configuration. A class II (mesial-oclusal-distal) cavity configuration was simulated on 20 extracted human third-molars (4 mm wide/3 mm deep). Etch-and-rinse adhesive (Scotchbond Multi Purpose, n=5, SBMP and Optibond FL, n=5, OPFL) and self-etch adhesives (Clearfil SE Bond, n=5, CSE and Optibond XTR, n=5, OPXTR) were applied. Class II restorations were performed by incremental technique and photo-activated (Bluephase/G2). Samples were sectioned to beam shape (1 mm² cross-section), placed on Geraldeli's device for µTBS test (0.5 mm/min cross-head speed). Fracture patterns were analyzed on stereomicroscope and classified as cohesive-resin, adhesive, mixed/resin or mixed/dentin. Samples (n=4) were prepared for scanning electron microscope observation. Data were submitted to one-way ANOVA with Split-Plot arrangement and Tukey's test (α=0.05). There were no statistically significant differences among SBMP, OPFL, CSE and OPXTR on CD (p>0.05). However, on PD for SBMP and OPFL, µTBS values were significantly lower compared to CSE and OPXTR (p<0.05). In all groups, mixed failure pattern was more frequently observed, except for SBMP/CD (adhesive). In class II type cavity configuration, PD location negatively influenced bond strength of etch-and-rinse adhesive systems. Opposite to self-etching adhesives, which presented higher bond strength values compared to etch-and-rinse adhesives in PD.

Biocompatibility and bond degradation of poly-acrylic acid coated copper iodide-adhesives

ObjectiveTo investigate the effect of poly-acrylic acid (PAA) copper iodide (CuI) adhesives on bond degradation, tensile strength, and biocompatibility. MethodsPAA-CuI particles were incorporated into Optibond XTR, Optibond Solo and XP Bond in 0.1 and 0.5mg/ml. Clearfil SE Protect, an MDPB-containing adhesive, was used as control. The adhesives were applied to human dentin, polymerized and restored with composite in 2mm-increments. Resin–dentin beams (0.9±0.1mm2) were evaluated for micro-tensile bond strength after 24h, 6 months and 1year. Hourglass specimens (10×2×1mm) were evaluated for ultimate tensile strength (UTS). Cell metabolic function of human gingival fibroblast cells exposed to adhesive discs (8×1mm) was assessed with MTT assay. Copper release from adhesive discs (5×1mm) was evaluated with UV–vis spectrophotometer after immersion in 0.9% NaCl for 1, 3, 5, 7, 10, 14, 21 and 30 days. SEM, EDX and XRF were conducted for microstructure characterization. ResultsXTR and Solo did not show degradation when modified with PAA-CuI regardless of the concentration. The UTS for adhesives containing PAA-CuI remained unaltered relative to the controls. The percent viable cells were reduced for Solo 0.5mg/ml and XP 0.1 or 0.5mg/ml PAA-CuI. XP demonstrated the highest ion release. For all groups, the highest release was observed at days 1 and 14. SignificancePAA-CuI particles prevented the bond degradation of XTR and Solo after 1year without an effect on the UTS for any adhesive. Cell viability was affected for some adhesives. A similar pattern of copper release was demonstrated for all adhesives.

Real-Time Imaging of Gap Progress during and after Composite Polymerization

The aims of this study were to observe the behavior of composite and formation of gaps during and immediately after light polymerization using swept source optical coherence tomography (OCT) and to compare the interfacial integrity of adhesives in cavities through 3-dimensional (3D) image analysis. Forty tapered cylindrical cavities (4-mm diameter, 2-mm depth) were prepared in bovine incisors and restored using Bond Force (BF), Scotchbond Universal Adhesive (SBU), OptiBond XTR (XTR), or Clearfil SE Bond 2 (SE2), followed by Estelite Flow Quick flowable composite. Real-time imaging was performed at the center of restoration by the OCT system (laser center wavelength: 1,330 nm; frequency: 30 KHz) during and up to 10 min after light curing. The 3D scanning was performed 0, 1, 3, 5, and 10 min after light curing. The percentages of sealed enamel and dentin interface area (E%, D%) were calculated using Amira software. In real-time videos, the initial gaps appeared as a bright scattered area mainly on dentin floor and rapidly progressed along the cavity floor. The timing, rate, and extent of gap formation were different among the specimens. From 3D visualization, gap progress could be seen on both enamel and dentin even after irradiation; furthermore, typical toroidal gap patterns appeared at the dentin floor of BF and SBU. XTR and SE2 showed nearly perfect sealing performance on the dentin floor up to the 10 min that images were recorded. From quantitative analysis, SE2 and XTR showed significantly higher E% and D% than other groups. SBU showed the smallest E% and BF showed a significantly smaller D% than other groups (P < 0.05). In conclusion, real-time observation of composite placement and 3D quantification of interfacial gaps were implemented within the experimental limitations. Interfacial gap formation during polymerization of the composite depended on the adhesive system used. The formed gaps continued to propagate after composite light curing finished.

Adhesive interfacial characteristics and the related bonding performance of four self-etching adhesives with different functional monomers applied to dentin

ObjectivesTo examine the interfacial chemical and morphological characteristics of four self-etching adhesives bonded to dentin with different functional monomers. Further, to evaluate the effects of this interaction between functional monomers and dentin on short-term in vitro bonding performance of the four adhesives. MethodsClearfil SE Bond (CSE) and Scotchbond Universal (SU) containing 10-methacryloxydecyl dihydrogen phosphate (10-MDP), Optibond XTR (OX) containing glycero-phosphate dimethacrylate (GPDM), and Adper Easy One (AEO) containing 6-methacryloyloxyhexyl dihydrogen phosphate (6-MHP) were applied to the dentin surface according to the instructions supplied with each. Interaction between the functional monomers and dentin was characterized using thin-film X-ray diffraction (TF-XRD) and scanning electron microscopy (SEM). The hydrophilicity of each acidic monomer was also assessed by chemical structure drawing software. Micro-tensile bond strength (μTBS) and nanoleakage were used to evaluate the bonding effectiveness of the adhesives, either immediately or after thermo-cycling (5°C–55°C) for 5000 cycles. ResultsTF-XRD showed that both CSE and SU exhibited 10-MDP–Ca nano-layering at the adhesive interface, but with different intensity when reacted with dentin. OX, that contains GPDM, demineralized the dentin surface more severely, forming long resin tags into the dentinal tubules, and gained the highest μTBS at the immediate time-point. Thermo-cycling adversely affected the μTBS and nanoleakage of AEO and OX, but had no significant influence on CSE and SU which contain 10-MDP. ConclusionsSelf-etching adhesives containing different structures/concentrations of functional monomers produced adhesive interfaces with obviously different chemical and morphological characteristics, which may have a direct impact on bonding effectiveness. Clinical SignificanceOur findings support the concept that the stable chemical bonding produced by 10-MDP to the Ca of hydroxyapatite is advantageous for durability of adhesive–dentin bonds. In contrast a higher immediate bond strength was achieved with the functional monomer GPDM that etched and wetted the dentin surface better.

Effect of Sonic Application of Self-etch Adhesives on Bonding Fiber Posts to Root Canal Dentin.

To evaluate the effect of sonic application of 5 different self-etch adhesives on the push-out bond strength of fiber posts in root canals. In a preliminary test, 24 teeth were treated with manual and sonically assisted bonding, then a composite cylinder was built up to test the shear bond strength as a proof of principle. In the main test, 120 root canals were endodontically prepared and divided into 10 groups: 5 self-etch adhesives (Futurabond DC, Futurabond M, Futurabond U, Optibond XTR, Universalbond), each applied under manual and sonic application modes. After insertion of the fiber posts using the specific adhesive and a dual-curing composite, the teeth were sectioned and the push-out test was performed. The specimens were analyzed by light and scanning electron microscopy. Statistical analysis was performed using the Shapiro-Wilk test, one-way ANOVA and the Tamhane test. Sonic application of self-etch adhesive systems did not increase the bond strength of fiber posts in root canals. In general, the bond strength decreased from the coronal to the apical part of the root canal, irrespective of the applied method. The best post retention was achieved with Futurabond U and Optibond XTR. Sonic application of self-etch adhesives did not improve the fiber post retention in the root canal and can therefore not be recommended. Nevertheless, sonic application of etch-and-rinse adhesives can increase the bond strength to coronal dentin.

Three-year Randomized Clinical Study of a One-step Universal Adhesive and a Two-step Self-etch Adhesive in Class II Composite Restorations.

To evaluate in a randomized clinical evaluation the 3-year clinical durability of a one-step universal adhesive and compare it intraindividually with a 2-step self-etch adhesive in Class II restorations. Each of 57 participants (mean age 58.3 years) received at least two extended Class II restorations that were as similar as possible. The cavities in each of the 60 individual pairs of cavities were randomly distributed to the 1-step universal adhesive (All-Bond Universal: AU) and the control 2-step self-etch adhesive (Optibond XTR: OX). A low shrinkage composite (Aelite LS) was used for all restorations, which were evaluated using slightly modified USPHS criteria at baseline and 1, 2, and 3 years. 114 Class II restorations were evaluated at three years. Eight restorations, 3 AU and 5 OX, failed during the follow-up, resulting in 94.7% (AU) and 91.2% (OX) success rates (p > 0.05). Annual failure rates were 1.8% and 2.9%, respectively.The main reason for failure was composite fracture. Class II composite restorations placed with a 1-step universal adhesive showed good short-term efficacy.

Reparability of two different CAD/CAM polymer materials using a light-cured composite and universal adhesives

ObjectiveTo evaluate the reparability of CAD/CAM polymer materials with universal adhesive systems. MethodsEighty blocks of polymethyl methacrylate (PMMA) and eighty blocks of polyoxymethylene (POM) were milled by the manufacturer (7mm of diameter and 4mm height). The top surface of all specimens was abraded with 50μm Al2O3. The 80 specimens of each material were randomly allocated to four experimental groups (n=20) according to the adhesive system used: OptiBond XTR, Futurabond M+, Scotchbond Universal or OptiBond Solo Plus. Each adhesive and the repairing composite resin (GrandioSO) were applied according the manufacturer's instructions. Specimens were stored in distilled water at 37°C for 48h and submitted to shear bond strength (SBS) tests. Fracture surfaces were observed and classified as: adhesive, cohesive or mixed type. SBS data were analysed with 2-way ANOVA and Kruskal–Wallis and Mann–Whitney tests were used to failure mode data (α=0.05). ResultsThe mean SBS yielded with PMMA specimens was significantly (p<0.001) higher than with POM. There were no statistical (p=0.062) differences between adhesive systems. Statistically significant (p<0.001) differences were found between failure mode observed in the two polymeric materials. No cohesive failure was obtained, with the POM specimens having mostly adhesive failures, in contrast with the PMMA with mostly mixed failures. No significant (p=0.925) differences in failure mode were identified between adhesives. ConclusionIt is possible to achieve an adequate adhesion bond to POM and PMMA. SBS values were higher in PMMA specimens than to POM but no differences were found between adhesive systems.

Microleakage comparison of three types of adhesive systems versus GIC-based adhesive in class V composite restorations

Background and aims: New dentin bonding agents and techniques have been developed to reduce microleakage and create higher bond strength. This in-vitro study compared the microleakage of three resin-based adhesives versus a GIC-based adhesive on class V composite restorations. Materials and Methods: Class V cavities were prepared on the buccal surfaces of 72 sound premolars, randomly assigned to six groups (n=12) and treated as follows: without any treatment (negative control group); total-etch (OptiBond Solo Plus); two-step self-etch (OptiBond XTR); one-step self-etch (OptiBond All-in-One) and GIC-based adhesive (Fuji bond LC) with pre-cure and co-cure techniques. The treated cavities were filled with a micro-hybrid resin composite (Point 4, Kerr). Following finishing and polishing procedures, the specimens were placed in 100% humidity, stored in distilled water, thermocycled and then immersed in a methylene blue, sectioned, evaluated for microleakage and scored on a 0 to 3 ordinal scale. Results: None of the adhesives tested were capable of completely eliminating marginal microleakage. There were statistically significant differences among the test groups at occlusal margins; but at cervical margins were not. The Fuji Bond LC with co-cure and control groups had significantly greater microleakage scores at the occlusal margins. At the cervical margins, the bonded restorations with OptiBond XTR and OptiBond All-in-One adhesives presented significantly lower microleakage scores. Also, there were no significant differences between the resin adhesive groups both at occlusal and cervical margins. The microleakage scores at the cervical margins were markedly higher than the occlusal margins in the groups bonded with OptiBond Solo Plus and Fuji Bond LC with pre-cure. The differences between Fuji Bond LC adhesive with pre-cure and co-cure techniques were significant. Conclusion: This study encourages application of the Fuji bond LC adhesive with pre-cure technique instead of the resin adhesives for marginal seal in class V composite restorations.

Influence of frequency on shear fatigue strength of resin composite to enamel bonds using self-etch adhesives

ObjectivesThe 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. MethodsA 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. ResultsRegardless 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. ConclusionsRegardless 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. SignificanceAccelerated fatigue testing provides valuable information regarding the long term durability of resin composite to enamel bonding using self-etch adhesive system.

Influence of different pre-etching times on fatigue strength of self-etch adhesives to dentin.

The purpose of this study was to use shear bond strength (SBS) and shear fatigue strength (SFS) testing to determine the influence on dentin bonding of phosphoric acid pre-etching times before the application of self-etch adhesives. Two single-step self-etch universal adhesives [Prime & Bond Elect (EL) and Scotchbond Universal (SU)], a conventional single-step self-etch adhesive [G-aenial Bond (GB)], and a two-step self-etch adhesive [OptiBond XTR (OX)] were used. The SBS and SFS values were obtained with phosphoric acid pre-etching times of 3, 10, or 15 s before application of the adhesives, and for a control without pre-etching. For groups with 3 s of pre-etching, SU and EL showed higher SBS values than control groups. No significant difference was observed for GB among the 3 s, 10 s, and control groups, but the 15 s pre-etching group showed significantly lower SBS and SFS values than the control group. No significant difference was found for OX among the pre-etching groups. Reducing phosphoric acid pre-etching time can minimize the adverse effect on dentin bonding durability for the conventional self-etch adhesives. Furthermore, a short phosphoric acid pre-etching time enhances the dentin bonding performance of universal adhesives.

Effect of frequency on the fatigue strength of dentin bonds.

This study aimed to investigate the effect of frequency on shear fatigue strength (SFS). The SFS of a resin composite bonded to dentin was determined using three self-etch adhesive systems: G-ænial Bond, Scotchbond Universal, and Optibond XTR. The staircase method of fatigue testing was used to determine the SFS at frequencies of 5, 10, and 20 Hz for 50,000 cycles. The failed bonding sites observed were classified based on the type of bond failure as follows: adhesive failure, cohesive failure in composite, cohesive failure in dentin, or mixed failure (partially adhesive, partially cohesive). A modified t-test with Bonferroni correction was used to analyze the SFS data, and a complex chi-square test was used to analyze the fracture modes. The SFS of OX was significantly greater than that of GB at both 5 and 10 Hz. However, no significant differences in SFS were found among the three frequencies (5, 10, and 20 Hz) in the three self-etch adhesive systems. Furthermore, no significant differences in bond failure mode were observed among the three frequency rates in all the three adhesives used.(J Oral Sci 58, 539-546, 2016).

Dentin bonding performance using Weibull statistics and evaluation of acid-base resistant zone formation of recently introduced adhesives.

Dentin bonding durability of recently introduced dental adhesives: Clearfil SE Bond 2 (SE2), Optibond XTR (XTR), and Scotchbond Universal (SBU) was investigated using Weibull analysis as well as analysis of the micromorphological features of the acid-base resistant zone (ABRZ) created for the adhesives. The bonding procedures of SBU were divided into three subgroups: self-etch (SBS), phosphoric acid (PA) etching on moist (SBM) or dry dentin (SBD). All groups were thermocycled for 0, 5,000 and 10,000 cycles followed by microtensile bond strength testing. Acid-base challenge was undertaken before SEM and TEM observations of the adhesive interface. The etch-and-rinse method with SBU (SBM and SBD) created inferior interfaces on the dentin surface which resulted in reduced bond durability. ABRZ formation was detected with the self-etch adhesive systems; SE2, XTR and SBS. In the PA etching protocols of SBM and SBD, a thick hybrid layer but no ABRZ was detected, which might affect dentin bond durability.

Influence of pre-etching times on fatigue strength of self-etch adhesives to enamel

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. 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. 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. Three seconds of phosphoric acid pre-etching prior to application of self-etch adhesive can enhance enamel bonding effectiveness.