Scotchbond Universal Research Articles

Resin tags formation by modified Renewal MI formulations in a carious dentine model.

To determine which components in a new restorative material (Renewal MI) improve its ability to form resin tags within demineralized dentine. Varied components included polylysine (PLS), monocalcium phosphate (MCP), powder to liquid ratio (PLR), 4-methacryloyloxyethyl trimellitate anhydride (4META), and polypropylene glycol dimethacrylate (PPGDMA). Urethane dimethacrylate (UDMA), containing PPGDMA (24 wt%) and 4META (3 wt%), was mixed with glass filler with MCP (8 wt%) and PLS (5 wt%). PLR was 3:1 or 5:1. Reducing MCP and/or PLS to 4 and 2 wt% respectively or fully removing MCP, PLS, 4META or PPGDMA gave 16 formulations in total. Renewal MI, Z250 (with or without Scotchbond Universal adhesive) and Activa were used as commercial comparators. Collagen discs were obtained by totally demineralizing 2 mm thick, human, premolar, coronal dentine discs by immersion in formic acid (4M) for 48 h. The restorative materials were then applied on top (n = 3), before dissolving the collagen in sodium hypochlorite (15%). SEM/EDX was employed to determine resin tags length, composition, and surface coverage. Tags were >400, 20 and 200 µm and covered 62, 55 and 39% of the adhesion interface for Renewal MI, Scotchbond and Activa, respectively. With experimental formulations, they were 200 and >400 µm long with high vs. low PLR and composed primarily of polymerized monomers. Percentages of the adhesion interface covered varied between 35 and 84%. Reducing PLS or MCP caused a decline in coverage that was linear with their concentrations. Reducing MCP had lesser effect when PLS or PLR were low. Removal of 4META caused a greater reduction in coverage than PPGDMA removal. PLS, MCP, 4META, PPGDMA and low PLR together enhance Renewal MI tags formation in, and thereby sealing of, demineralized dentine.

Tooth-composite bond failure with a universal and an etch-and-rinse adhesive depending on mode and frequency of application

ObjectivesTo evaluate the effect of an additional layer of universal adhesive on the interfacial enamel/dentin-composite gap formation in relation to application mode and aging, via spectral domain optical coherence tomography (SD-OCT) and scanning electron microscopy (SEM). MethodsIn vitro class V cavities in 114 caries-free premolars were restored by applying one or two layers of a universal adhesive (Scotchbond Universal, SBU) in self-etch (se) and etch-and-rinse (er) mode or the reference adhesive OptiBond FL (OFL-er). The restorations were imaged by SD-OCT (six groups, n = 8) and SEM (n = 3) directly after filling (t1), water storage (t2, 24 h), embedding (t3), and thermo-mechanical loading (t4, TCML). The interfacial gaps were quantified using 26 parameters and analyzed using principal component analysis and linear mixed effect models. ResultsGap formation at enamel and dentin was significantly influenced by the adhesive, the application mode and number of layers (p < 0.001). This was due to the influence of the SBU-er mode (p < 1e-05), which showed significantly more gap formation and a greater range of variation with double application when compared to SBU-se and OFL. The fewest interfacial gaps occurred with one or two applications of OFL-er and one layer of SBU-er. SignificanceAdhesive application mode and the number of adhesive layers are relevant factors in the tooth-composite bond failure. Double application worsened the adaptation of SBU to freshly prepared dentin conditioned with phosphoric acid.

In vitro performance of an autocured universal adhesive system in bonding to dentin

BackgroundThe successful integration of resin-based dental adhesives significantly impacts restorative dentistry, providing efficient and aesthetically pleasing caries treatments. Among various adhesives, one-step self-etching adhesives (1-SEAs) have gained popularity due to their simplicity and short application time. However, concerns have been raised regarding their bonding performance and marginal adaptation characteristics, which differ from two-step self-etching adhesives (2-SEAs) and three-step etch-and-rinse adhesives. Additionally, light-cured bonding materials may encounter challenges in deep cavities and inaccessible areas, necessitating extended light irradiation time. Autocured bonding materials are a potential solution, but limited comparative studies have been conducted on their performance.MethodsIn this in vitro study, we evaluated a new autocured universal bonding material (Bondmer Lightless 2) and compared the results with recent light-cured bonding materials. Microshear bond strength (μSBS) tests were performed on 25 human molars using five different combinations of adhesives and composite resins: Bondmer Lightless 2 with Estelite Bulk Fill Flow (BE group), Bondmer Lightless 2 with a prototype composite resin (BO group), Prime&Bond Universal with SDR flow + (PS group), Scotchbond Universal with Filtek Bulk Fill (SF group), and G-Premio Bond with Gracefil BulkFlo (GG group). The bond strengths and failure modes were assessed using a universal testing machine and scanning electron microscope (SEM), respectively. Marginal adaptation was evaluated using swept-source optical coherence tomography (SS-OCT) and confocal laser scanning microscopy (CLSM) on 40 sound bovine maxillary incisors.ResultsThe μSBS test showed no significant differences in bond strength among the tested groups. Most failure modes were observed at the bond interface between the adhesive and the dentin. The autocured bonding material demonstrated significantly higher marginal adaptation (SI%) than PS, SF, and GG. The CLSM images corresponded with gaps observed in the SS-OCT images, indicating improved marginal sealing in the autocured group.ConclusionsThe new autocured universal bonding material exhibited comparable bond strength to a conventional light-cured material while demonstrating a superior marginal adaptation level. This finding suggested that the autocured material could be a valuable alternative, especially when extended light irradiation would pose a challenge. Further clinical studies would be warranted to evaluate the performance of the autocured bonding material in actual restorative dental practice.

Long-term Evaluation of Dentin Bonding Properties of the Photoinitiator System Contained in Universal Adhesives Used in Fiber-Post Luting Procedures.

This study evaluated the long-term push-out bond strength (PBS) and nanoleakage (NL) of universal adhesives with different photo-initiator systems in the root canals of teeth in which fiber posts were luted. One-hundred twenty endodontically treated human premolars were randomly divided into 12 groups based on the following factors: adhesives (Scotchbond Universal [SBU], Ambar Universal [AMB], and Ambar Universal APS [AMB-APS]); adhesive strategy (etch-and-rinse and self-etch), and time of testing (immediately vs after 2 years). The posts were cemented, sectioned into slices, tested for PBS at 0.5 mm/min, and examined for NL using scanning electron microscopy immediately thereafter or after 2 years of water storage. Data were evaluated using a four-way ANOVA (root thirds vs time vs universal adhesive vs adhesive strategies) and Tukey's test (α = 5%). For both evaluation times, AMB-APS demonstrated no significant difference in the PBS or NL when different radicular thirds were compared (p > 0.05). However, for SBU and AMB, the cervical third demonstrated higher PBS and lower NL than those of the apical third at both time points (p < 0.0001). AMB-APS exhibited higher PBS and lower NL in the apical third in comparison with SBU and AMB (p < 0.0001). SBU and AMB displayed a significant decrease in the PBS and increased NL after 2 years (p < 0.0001), whereas AMB-APS demonstrated no significant signs of degradation even after 2 years of water storage (p > 0.05). Independent of the root third evaluated, the universal adhesive containing APS photo-initiator system demonstrated bonding stability at the adhesive interface between the root canal and fiber posts, even after 2 years of water storage.

Influence of universal adhesives and silane coupling primer on bonding performance to CAD-CAM resin-based composites: A laboratory investigation.

Obtaining strong resin bonds to computer-aided design and computer-aided manufacturing (CAD-CAM) resin-based composites with dispersed fillers (CCRBCs) poses a challenge. Therefore, this study aimed to assess the effect of three universal adhesives and a two-component silane coupling agent on the shear bond strength to three (CCRBCs). Eight hundred and sixty-four specimens of Brilliant Crios, Lava Ultimate, and Tetric CAD were polished or grit blasted, bonded with Adhese Universal DC, One Coat 7 Universal (OC7), and Scotchbond Universal Plus Adhesive (SBU) with or without a silane primer. Shear bond strength was measured after 24 h and 10,000 thermocycles. Linear regressions were performed (α = 0.05). After thermocycling, bond strengths were similar for the universal adhesives on polished Brilliant Crios and Lava Ultimate (p ≥ 0.408). Grit blasted Tetric CAD showed no significant differences (p ≥ 0.096). The silane primer had minimal impact on grit blasted Tetric CAD (p ≥ 0.384). The silane primer increased the bond strength of OC7 to Brilliant Crios (p = 0.001) but decreased the adhesion of SBU to Brilliant Crios and Lava Ultimate (p ≤ 0.018). Bond strength of universal adhesives varied with CCRBC type. The two-component silane coupling agent showed mixed effects on adhesive performance. Selecting universal adhesives from the same CCRBC product line does not always guarantee superior bond strength. The efficacy of silane coupling agents differs based on the bonding substrate.

Bond strength to dentin of a Polymer-infiltrate ceramic-network material cemented with dual resin cements submitted to different adhesive strategies

The purpose of the present in vitro study is to assess the immediate and long-term bond strength of a self-adhesive and conventional resin luting agents with a new hybrid restorative material to dentin. Blocks of a polymer-infiltrated ceramic-network (PICN) material (VITA Enamic) were cemented to a flat exposed dentin surface through different protocols. The groups were divided considering the combination of resin luting agent and ceramic surface treatment (U200 – Relyx U200 with silane; Ult + Sil – Relyx Ultimate with silane; Ult + SBU – Relyx Ultimate with Scotchbond Universal) and dentin treatment (NT – no dentin treatment; ER – etch-and-rinse with 35 % phosphoric acid) (n = 6). Beam-shaped specimens were obtained by cutting the cemented restorations. Specimens were submitted to microtensile bond strength in a universal testing machine (EMIC). Half of the specimens were tested 24 h after cementation, and the other half were tested after 12 months of water storage. ANOVA revealed one significant interaction between “time” and “dentin treatment” factors, as ER strategy was associated with bond strength decreases after 12 months. All resin luting agents (u200, Ult + Sil, and Ult + SBU) presented higher immediate μTBS with ER adhesive strategy. As the groups Ult + Sil, with both ER and SE adhesive strategies, and (Ult + SBU), with ER adhesive strategy, showed higher μTBS values after 12 months. It was concluded that conventional dual resin cement, combined with ER strategy produced better bond strength to dentin when cementing indirect PICN restoration.

Does the application of dimethyl sulfoxide improve resin bonding to eroded dentine? Four-year in vitro evaluation.

To evaluate the effect of dimethyl sulfoxide (DMSO) on the microtensile bond strength (µTBS) and nanoleakage (NL) of universal adhesives on eroded dentine, immediately and after four years of water storage. Sixty-four sound human molars were distributed into 16 groups according to (1) Dentine surface (sound and eroded dentine); (2) dimethyl sulfoxide application (with or without); (3) Application mode (etch-and-rinse or self-etch) and (4) Storage time (immediate and four years). One mild universal adhesive was used (Scotchbond Universal). The restoration was then performed with a composite resin and the specimens were sectioned into resin-dentine bonded sticks. Resin-dentine bonded sticks were tested (immediately and after four years of water storage) for µTBS (0.5mm/min) or used to assess NL. Data on μTBS and NL were analyzed using four-way ANOVA and Tukey's test (α=0.05). Only the 3-way cross-product interaction 'substrate vs DMSO vs time' was statistically significant (p=0.007). Eroded dentine showed a lower mean of µTBS and a higher mean of NL values than sound dentine. However, when DMSO was applied, no significant decrease of μTBS or NL values was observed after four years of water storage, regardless of adhesive strategies, or dentine evaluated, when compared to immediate results. Water-based DMSO pre-treatments not only prevent degradation of MDP-containing simplified adhesives but also serve as a potential alternative to improve long-term bonding properties to eroded dentine. The versatility of using a single pre-treatment for both self-etch or etch-and-rinse bonding to eroded dentin may facilitate future clinical applications.

Novel Universal Bond Containing Bioactive Monomer Promotes Odontoblast Differentiation In Vitro.

The development of multifunctional materials has been expected in dentistry. This study investigated the effects of a novel universal bond containing a bioactive monomer, calcium 4-methacryloxyethyl trimellitic acid (CMET), on odontoblast differentiation in vitro. Eluates from bioactive universal bond with CMET (BA (+), BA bond), bioactive universal bond without CMET (BA (-)), and Scotchbond Universal Plus adhesive (SC, 3M ESPE, USA) were added to the culture medium of the rat odontoblast-like cell line MDPC-23. Then, cell proliferation, differentiation, and mineralization were examined. Statistical analyses were performed using a one-way ANOVA and Tukey's HSDtest. The cell counting kit-8 assay and alkaline phosphatase (ALP) assay showed that cell proliferation and ALP were significantly higher in the 0.5% BA (+) group than in the other groups. In a real-time reverse-transcription polymerase chain reaction, mRNA expression of the odontogenic markers, dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP-1), was significantly higher in the 0.5% BA (+) group than in the BA (-) and SC groups. Calcific nodule formation in MDPC-23 cells was accelerated in the BA (+) group in a dose-dependent manner (p < 0.01); however, no such effect was observed in the BA (-) and SC groups. Thus, the BA bond shows excellent potential for dentin regeneration.

Effect of Er,Cr:YSGG and Nd:YAG Lasers on Microleakage of Composite Resin Restorations Using Universal Adhesives

Background: Clinical long-term success of bonded restorations is depended to reduce marginal microleakage and the laser application with combination of new bonding systems may play positive role. The aim of this study was comparative evaluation of Er,Cr:YSGG and Nd:YAG lasers effect on microleakage of class V composite resin restorations using several universal adhesives. Methods: In this in vitro study, standard class V cavities were prepared on both lingual and buccal surfaces of 72 intact premolar teeth. For evaluation of microleakage, the cavities were divided into 9 groups according to conditioning method (n=15): G1: G-Premio Bond [GP]; G2: Scotchbond Universal Adhesive [SU]; G3: All-Bond Universal [AB]; G4: GP+Nd:YAG Laser; G5: SU+Nd:YAG Laser; G6: AB+Nd:YAG Laser; G7: GP+Er,Cr:YSGG Laser; G8: SU+Er,Cr:YSGG Laser; and G9: AB+Er,Cr:YSGG Laser. The cavities were filled with composite resin and then subjected to thermocycling, placed in methylene blue solutions, embedded in resin blocks and vertically cut in the bucco­lingual direction. The microleakage in occlusal and gingival margins was defined as linear penetration of methylene blue and determined with a stereomicroscope to assign microleakage scores using a four­point scale. Data were analyzed by using SPSS software and Kruskal-wallis and Mann-Whitney U tests. Results: Microleakage scores had statistically significant different before and after laser irradiation in dependent to the adhesive used (P&lt;0.05) but there were no significant different between Nd:YAG and ER,Cr:YSGG laser, also between different universal adhesives (GP, SU, AB). The results showed that total microleakage scores of occlusal margins had significant statistical different in comparison with gingival margins (P&lt;0.001). Conclusion: The results indicate that Nd:YAG and Er,Cr:YSGG lasers irradiation, after using the investigated universal adhesives, had a positive effect on reducing the microleakage of composite Class V restorations. The microleakage rate was shown to be independent of adhesives and lasers type used in this study.

Does dimethyl sulfoxide promote the bonding performance of different universal adhesives to dentin in etch-and-rinse approach?

This study examined the influence of dimethyl sulfoxide (DMSO) on the microtensile bond strength (μTBS) of universal adhesives to dry or wet dentin in the etch-and-rinse approach. Human third molars were cut to reveal the flat mid-coronal dentin surface. The specimens were randomly divided into 16 groups (n = 8) based on dentin condition (dry or wet), dentin pretreatment (with or without DMSO), and adhesive agents (Scotchbond Universal (SBU), Ambar Universal Bond (AUB), G-Premio Bond (GPB), and Clearfil Universal Bond (CUB). The etched-dentin surfaces were pretreated with a 50% DMSO solution before adhesive application. After 24 h or thermocycling, the resin-dentin beams were tested using the microtensile device. μTBS data were analyzed using a four-way ANOVA (α = 0.05). Scanning electron microscopy (SEM) was used to detect nanoleakage at adhesive interfaces. DMSO increased μTBS to wet and dry dentin of CUB, SBU, and AUB but not GPB. CUB, SBU, and AUB bonded better to wet dentin than dry dentin, but GPB bonded equally well to both. DMSO's nanoleakage effect dependent on dentin moisture and the adhesive agent used.

Effect of the Absence of HEMA on the Bonding Properties of Universal Adhesive Systems Containing 10-MDP: An In Vitro Study.

To evaluate the absence of 2-hydroxyethyl methacrylate (HEMA) on the adhesive properties with enamel and dentin of universal adhesive systems containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP). One hundred and twelve caries-free third molars were used to test adhesion to dentin (n=64) and enamel (n=48). For each substrate, teeth were divided into eight experimental groups: four different adhesives each using two adhesive strategies. The adhesives used were: (1) Scotchbond Universal (SBU, 3M Oral Care, St Paul, MN, USA) as a HEMA-containing universal adhesive; (2) Gluma Bond Universal (GBU, Kulzer, Hanau, Germany); (3) Solare Universal Bond (SUB, GC, Tokyo, Japan); and (4) Zipbond Universal (ZIP, SDI, Victoria, Australia) as HEMA-free universal adhesives. The adhesive strategies used were etch-and-rinse (ER) and self-etch (SE). For dentin tests, the occlusal third of the crown of all teeth was removed and an adhesive protocol was applied. After completing the restoration, specimens were sectioned into bonded sticks (0.8 mm 2) and tested for microtensile bond strength (μTBS), in situ degree of conversion (DC), and nanoleakage (NL) by scanning electron microscopy. For enamel tests, teeth were sectioned into four parts (buccal, lingual, and proximal), and an adhesive protocol was applied. After completing the restoration, the specimens were tested for their microshear bond strength (μSBS). For in situ degree of conversion (DC) and nanoleakage (NL) evaluation of enamel, the specimens were sectioned in slices to be evaluated. The data for each substrate were subjected to two-way ANOVA and Tukey's test (α=0.05) for each property evaluated. The SBU and ZIP adhesives showed the highest μSBS, and DC (dentin and enamel) and lower NL (dentin) values compared to GBU and SUB (p=0.001). However, SBU showed better results in terms of μTBS and μSBS (SE strategy), and DC (dentin and enamel) than ZIP. Strategy ER presented higher values of μTBS and μSBS when compared to strategy SE (p=0.001), except for SBU. The effect of the absence of HEMA in commercial universal adhesive systems on enamel and dentin adhesive properties appears to be material-dependent.

Bonding performance of universal adhesives to eroded dentine: A 6-year evaluation

ObjectivesTo evaluate the microtensile bond strength (µTBS) and nanoleakage (NL) of several universal adhesives to eroded dentine (ED) using etch-and-rinse (ER) and self-etch (SE) strategies, immediately and after 6 years of water storage. Material and methodsFour hundred and eighty human molars were distributed into 60 groups according to dentine substrate (sound dentine [SD], eroded with soft drink, or eroded with citric acid), application method of the adhesive (SE or ER), and the adhesives used: 1. All-Bond Universal, 2. Ambar Universal, 3. Clearfil Universal, 4. Futurabond U, 5. One Coat 7 Universal, 6. Peak Universal Bond, 7. Prime&Bond Elect, 8. Scotchbond Universal, 9. Tetric n-bond Universal, and 10. Xeno Select. The restoration was then performed with a composite resin, and the specimens were sectioned into resin-dentine bonded sticks. The sticks were tested (immediately or after 6 years of storage) for µTBS (0.5 mm/min) or used to assess NL. The eroded dentine surfaces were also examined using FE-SEM to evaluate the NL. Data for µTBS were analyzed by four-way ANOVA and Tukey's post-hoc test (a = 0.05), and the NL was analyzed by Kruskal–Wallis and the Wilcoxon Signed Rank Sum test (a = 0.05). ResultsIn ED, there was no difference in μTBS and NL between ER and SE strategies (p > 0.05). Most μTBS and NL values obtained for ED were lower and higher, respectively, than those for SD (p < 0.005). Additionally, the worst results (μTBS and NL) were observed for erosion with citric acid groups in comparison with erosion with soft-drink groups (p < 0.007). After 6y, μTBS was generally lower and NL higher for all substrates, adhesives, and strategies (p < 0.05), except for AMB, SBU, and TEU in dentine eroded with citric acid. The lowest μTBS and highest NL values were observed for ABU, FBU, OCU, PUB, PBE, and XEN in both types of eroded dentine and evaluation times (p < 0.002). Conclusion: The use of MDP-containing adhesives seems to be essential to maintain adhesion to eroded dentine. However, other factors such as acidity should be considered. Clinical significanceThe bonding of eroded dentine is a challenge. However, the use of MDP-containing universal adhesives showed less degradation after long-term evaluation.

Effect of irradiance and exposure time on the adhesive properties of universal adhesives after 2years of storage.

This study aims to evaluate the effects of exposure time and irradiance on the dentin bonding properties (microtensile bond strength (μTBS) and nanoleakage (NL)) of the Clearfil Universal Bond Quick (CUQ) adhesive and Scotchbond Universal Adhesive (SBU) immediately and after 2years of water storage. Hence, 128 human molars were randomly assigned to 16 groups based on adhesive strategy, irradiance/exposure times, and storage time for each universal adhesive tested. The adhesives were applied using the etch-and-rinse and self-etch strategies and were light-cured using four different irradiance/exposure times: 1400 mW/cm2 for 5s (1400 × 5), 1400 mW/cm2 for 10s (1400 × 10), 3200 mW/cm2 for 5s (3200 × 5), and 3200 mW/cm2 for 10s (3200 × 10). Then, each sample was restored and sectioned into a resin-dentin bonded stick to be tested for μTBS and NL (immediately and after 2years of water storage). The mean μTBS and NL of all resin-dentin bonded sticks from the same hemi-tooth (factor time) were statistically analyzed using a three-way ANOVA and Tukey's test (a = 0.05). Despite a significant decrease in the μTBS values for all groups after 2years of water storage, the 3200 × 5 group showed higher μTBS values, whereas the 3200 × 10 group showed lower μTBS values for both universal adhesives tested. Although a significant increase in the NL values was observed for all groups after 2years of water storage, the 3200 × 10 group showed higher NL values than the other groups (p < 0.001). Results indicate that light-curing the adhesive layer with 14-16J/cm2 led to an improvement in the stability of the resin-dentin adhesive interface. A longer exposure time (10s) coupled with a higher irradiance (3200 mW/cm2) resulted in a greater degree of degradation of the adhesive interface. To guarantee better stability of the adhesive interface, clinicians could be preferred a light-cured universal adhesive layer with 14-16J/cm2. Higher irradiances should be avoided.

Effect of Self-Cured and Self-Etch Adhesive Systems on Shear Bond Strength After Photodynamic Therapy and Disinfection with Different Types of Lasers

Effect of Self-Cured and Self-Etch Adhesive System on Shear Bond Strength After Photodynamic Therapy and Disinfection with Different Types of Lasers&#x0D; &#x0D; Ayşe Çeşme1-a*, Ihsan Hubbezoğlu1-b&#x0D; 1 Sivas Cumhuriyet University, Faculty of Dentistry, Department of Restorative Dentistry Sivas, Türkiye.&#x0D; &#x0D; ABSTRACT &#x0D; Objectives: The aim of this study was to investigate the strength of shear bonding of self-cured and self-etch adhesive systems to dentin after surface disinfection with Photodynamic Therapy (PDT), Er:YAG, Nd:YAG, and KTP laser.&#x0D; Materials and Methods: In the study, 6 main-groups were formed as Control, Er:YAG Laser, Nd: YAG Laser, KTP Laser, KTP Laser activated PDT and Diode Laser activated PDT. Each group was divided into two subgroups; Self-cured (Tokuyama Universal) and self-etch (Scotchbond Universal) adhesive system(n=10). 120 molar teeth were prepared to expose dentin surfaces. After disinfection and adhesive application, nanohybrid composite resin with a diameter of 3 mm and a height of 2 mm was applied to the dentin surface with the help of transparent molds. All samples were thermally cycled 5.000 times at 5°C and 55°C. Shear bond strength (SBS) test was applied to the samples in a universal test device.&#x0D; Results: The differences between the Er:YAG laser group and the control, KTP and Nd:YAG laser groups of the self-cured adhesive samples were statistically significant. While the differences between the Nd:YAG laser group and the PDT groups were statistically significant (p

The effect of an extra hydrophobic resin layer on the bond strength and durability of one-step universal adhesives used as a primer

ObjectivesTo determine the effect of an extra hydrophobic resin layer (EHL) on the bond strength and durability of three different pH one-step universal adhesives (UAs) utilized in self-etch (SE) mode, and to explore whether UAs can be used as a primer in two-step bonding system. MethodsThree different pH UAs were utilized: G-Premio Bond (GPB), Scotchbond Universal (SBU), All-Bond Universal (ABU), while the bonding agent of Clearfil SE Bond 2 (SE2) was selected as the EHL. For the EHL groups, EHL was applied after the air blow of each UA and before light curing. The microtensile bond strength (μTBS), fracture modes, interfacial structures and nanoleakage (NL) were evaluated after 24 h water storage and after 15,000 thermal cycling (TC). Elastic modulus (EM) and hardness (H) was tested by a nanoindenter after 24 h. ResultsSignificantly higher μTBS was achieved in the GPB+EHL group compared with GPB both at 24 h and after 15,000 TC, while the additional use of EHL did not improve the μTBS of SBU and ABU significantly both at 24 h and after 15,000 TC. GPB+EHL demonstrated lower NL than GPB. The mean EM and H of the adhesive layer in GPB+EHL was significantly decreased compared with GPB. ConclusionsThe results indicated that the bond strength and durability of low pH one-step UA (GPB) were significantly improved by additional application of EHL both at 24 h and after 15,000 TC, while no significant improvement was observed for ultra-mild one-step UAs (SBU and ABU). Clinical significanceThis study indicates that GPB can be used as a primer in a two-step bonding system, while SBU and ABU may not be as effective. These findings may help guide clinicians in selecting the appropriate UAs and bonding techniques for different clinical scenarios.

Immediate and Late Repair of Microhybrid Resin Composites: Effect of Silane Coupling Agent, Universal Adhesives and Photo Polymerization.

This study investigated the effect of silane coupling agent and universal adhesive application on repair bond strength of resin-based composite after bur grinding. Microhybrid resin composite (Charisma Smart) blocks (N=80; 8x8x4 mm3) were prepared, aged (37°C; 1 month), roughened, etched and randomly divided into two groups. Silane was applied to half of the groups (Porcelain Primer, Bisco), before one of the following universal primers/adhesives was applied: a) Scotchbond Universal (3M), b) All-Bond Universal (Bisco), c) G-Premio Bond (GC), and d) Clearfil SE Bond (Kuraray). In each adhesive group half of the group was photo-polymerized. The blocks were repaired with the same size resin composite and segmented into beams. Half of the beams were subjected to micro-tensile bond test (1 mm/min), while the other half was aged (37°C; 6 months) prior to testing. Failure modes were analyzed using Scanning Electron Microscopy (SEM). Data were analyzed using repeated measures of ANOVA, Tukey's post-hoc, and paired t-tests (alpha=0.05). The silane application did not affect the repair bond strength regardless of photo-polymerization of the adhesive resin. The repair bond strength decreased significantly after 6 months when adhesive resin was not photopolymerized (p⟨0.05). Photo-polymerizing universal adhesives might ensure higher repair bond strength and its maintenance after aging.

Three-Dimensional Printed Resin: Impact of Different Cleaning Protocols on Degree of Conversion and Tensile Bond Strength to a Composite Resin Using Various Adhesive Systems.

The present investigation tested the effect of cleaning methods and adhesives on the tensile bond strength (TBS) of a resin-based composite luted to a temporary 3D printed resin. Substrates (n= 360) were printed using a Rapidshape D20II and cleaned with a butyldiglycol-based solution, isopropanol, or by centrifugation. Specimens were air-abraded with Al2O3 (mean particle size 50 µm) at 0.1 MPa followed by pretreatment (n = 30/subgroup) with: (1) Clearfil Ceramic Primer (CCP); (2) Clearfil Universal Bond (CUB); (3) Scotchbond Universal Plus (SUP) or 4. Visio.link (VL) and luted to PanaviaV5. TBS (n = 15/subgroup) was measured initially (24 h at 37 °C water) or after thermal cycling (10,000×, 5/55 °C). The degree of conversion (DC) for each cleaning method was determined prior and after air-abrasion. Univariate ANOVA followed by post-hoc Scheffé test was computed (p < 0.05). Using Ciba-Geigy tables and chi-square, failure types were analyzed. The DC values were >85% after all cleaning methods, with centrifugation showing the lowest. CCP pretreatment exhibited the lowest TBS values, with predominantly adhesive failures. The combination of CCP and centrifugation increased the TBS values (p < 0.001) compared to the chemical cleaning. CUB, SUP, and VL, regardless of cleaning, can increase the bond strength between the 3D printed resin and the conventional luting resin.

Effect of full-step versus simplified resin cement luting strategies on the push-out bond strength of indirect resin composite restorations bonded to dentin

Indirect restorations made of resin composite materials are increasingly used yet there is no consensus in the literature on how different luting strategies influence the bond strength. The aim of this was to study the influence of luting strategy and aging on the adhesion of indirect restorations on dentin. Bovine incisors (N = 120) received conical cavities and filled them with resin composite. The cone sets were divided into 8 groups (n = 15 each) and the cylinders were cemented according to: ‘Luting strategy’ (U200: Self-adhesive cement resin; ULT: Scotchbond Universal + RelyX Ultimate; SB2: Phosphoric Acid + Adper Single Bond 2 + RelyX ARC; SBMP: Phosphoric Acid + Scotchbond Multi-purpose + ARC) and ‘Aging’ (Tc: With thermocycling/10.000 cycles: 5–55 °C; Without thermocycling). The specimens were subjected to a Push-out Bond Strength (σ) (100 kgf; 0.5 mm/min). Stereomicroscope and scanning electron microscopy (SEM) images were made to classify the failures. Data (MPa) were submitted to two-way-ANOVA, Tukey (α = 5%), and Weibull tests. ANOVA revealed that ‘luting strategy’ and ‘aging’ were statistically significant. When the factor ‘TC’ was evaluated separately, the TC groups presented higher bond strength than the unaged groups. As for the non-thermocycling groups, the different luting strategies had no statistical difference, except for the SB2 group, which was lower than ULT. Among all groups, TC, U200_Tc, SBMP_Tc, and ULT_Tc were statistically similar and significantly higher than that of the SB2-Tc group. The Weibull modulus was statistically different among the groups but characteristic strength was significant. Mixed failures were predominantly observed. Self-conditioning strategy promoted higher bond strength than the two-step conventional strategy but after thermocycling, the two-step conventional strategy presented the worst performance among the experimental groups.

Microtensile Bond Strength of Different Bonding Agents to Superficial and Deep Dentin in Etch-and-Rinse and Self-Etch Modes.

Objectives: This study aimed to assess the microtensile bond strength (µTBS) of etch-and-rinse (E&R), self-etch (SE), and universal adhesives to superficial and deep dentin. Materials and Methods: In this in vitro study, 40 sound third molars were randomly divided into two main groups of superficial and deep dentin. Based on our classification, superficial dentin was right beneath the deepest occlusal groove, and deep dentin was 2mm beneath the deepest occlusal groove. Each group was divided into 4 subgroups (n=20) for application of Adper Single Bond 2 (ASB), Clearfil SE Bond (CSE), and Scotchbond Universal (SBU) in E&R and SE modes along with Charisma Smart composite resin on dentin. The specimens were incubated in distilled water at 37°C for 24 hours and their µTBS was then measured. The mode of failure was determined under a stereomicroscope at ×40 magnification. Data were analyzed by one-way ANOVA (alpha=0.05). Results: The highest µTBS belonged to the superficial dentin/SBU/E&R group. The µTBS was significantly higher in superficial dentin than deep dentin for all adhesives (P=0.005). There was no significant difference in mode of failure among the groups. Conclusion: Based on the results obtained in the present study, type of bonding agent and application mode affected µTBS. In use of universal adhesive, E&R mode can improve µTBS.

Solvation role of dimethyl sulfoxide on the interaction with dentin bonding systems after 30 months.

To determine whether DMSO could serve as an effective pretreatment to improve the mechanical properties and minimize the degradation of the adhesive interface, through the degree of conversion (DC) and bond strength to dentin of different categories of dentin bonding systems (DBSs) after 30 months. DMSO (0, 0.5, 1, 2, 5, 10vol%) were incorporated into four categories of DBSs: Adper Scotchbond Multipurpose (MP), Adper Single Bond 2 (SB), Clearfil SE Bond (CSE) and Adper Scotchbond Universal (SU). DC was evaluated by Fourier transform infrared spectroscopy (FTIR). For microtensile bond strength test (µTBS), 1 % DMSO were applied on dentin as pretreatment before DBSs. For SU, both strategies were tested. Specimens for µTBS were tested after 24h, 6 and 30 months. DC and µTBS data were subjected to two-way ANOVA and Tukey test (α<0.05). Incorporating 5 %/10 % DMSO increased the DC of CSE. Controversially, when combined with SU, 2 % and 10 % DMSO jeopardized the DC. Regarding µTBS, 1 % DMSO pre-treatment increased the bond strength for MP, SB, SU-ER and SU-SE. After 30 months, MP, SU-ER and SU-SE showed a decrease compared to baseline but remained higher than the control. DMSO pretreatment may be a useful strategy to improve the bond interface over time. Its incorporation seems to favor the non-solvated systems regarding DC while it seems to show long-term benefits for bond strength using 1 % DMSO for MP and SU systems.