Significant Differences In Bond Strength Research Articles

Characterization of 2D As2S3 crystal by Raman spectroscopy

AbstractAs2S3 is a semiconductor, which is known as a layer crystal with structure that is very similar to the metal chalcogenides, such as MoS2 and graphite. In such crystalline structure, the molecular unit is extended in two dimensions indefinitely. The unit cell of As2S3 contains two layers with bond length of 2.24A within the layer and 3.56A between the layers. Large difference between interlayer and intralayer bond length corresponds to a significant difference in bond strengths. The weak bonding between layers primarily occurs via van der Waals interactions. Optical phonons in 2D layer crystal As2S3 have been investigated by Raman scattering in temperature range of 4K-270K in two polarizations in the layer plane (ac plane). Our experimental data shows strong polarization dependence of Raman bands in ac plane for internal mode (intra-layer interactions). Additionally, it presents low frequency band, due to the weak inter-layer interaction. The important evidence for the dominance of layer symmetry with very weak interaction between the layers provides understanding of structural motives of As2S3 and may predict optical / electronic properties of similar 2D materials.

Influence of Protease Inhibitors on Bond Degradation of Self-Etch Adhesive Systems to Caries-Affected Dentin: An <i>in Vitro</i> Study

Background: A decline in pH and dissolution of the inorganic content of the dental tissues are followed by exposure of the organic portion of the tooth, which, in dentin, is largely composed of collagen fibres. These unprotected fibres are then degraded by metalloproteinases and cysteine cathepsins, proteolytic enzymes present in dentin. We evaluated the influence of protease inhibitors on the bond strength of a self-etch adhesive system to caries-affected dentin. Eighty permanent third molars were selected for the study. Dentinal caries were induced artificially by the microbial method and the teeth were divided in four groups: G1—application of Clearfil SE Bond adhesive system (CL); G2—2% chlorhexidine (CLX) + CL; G3—sodium bicarbonate (BIC) + CL; G4—BI + CLX + CL. Bond strength was assessed immediately and at six months. During the six months, the specimens were stored in distilled water. Microtensile bond strength testing was performed. On immediate testing, there was no significant difference in bond strength across the control, BIC, and CLX groups. The combination of BIC + CLX, however, led to an immediate, significant reduction in bond strength. After six months, bond strength was reduced in all groups. The highest bond strength was obtained in the control group (P 0.05). Most fractures were adhesive, both immediately and at six months. We concluded that the cavity pretreatment with 2% CLX or 2% BIC did not have an immediate negative impact on bond strength of the Clearfil SE Bond system. After specimens were stored for six months in water, their bond strength of specimens was reduced in all groups. This reduction was the greatest in the groups exposed to the inhibitors.

Shear bond strength of ceramic bracket bonded to different surface-treated ceramic materials

BackgroundThis study evaluated the effect of ceramic surface treatments on bond strength of ceramic brackets to machine-able ceramics and ceramic veneering metal.Material and MethodsMachined ceramic specimens (10x10x1.5 mm) were prepared from Empress® CAD (EP), and e.max® CAD (EM). Ceramic veneering metal specimens (PF) were fabricated from sintered d.Sign® porcelain (1.27 mm thickness) over d.Sign®10 metal (0.23 mm thickness). Each ceramic was divided into 3-groups and treated surface by Er-YAG laser (LE) or etching with 9.6% HF acid for 5 seconds (A5) or 15 seconds (A15). Resin adhesive (Transbond™-XT) was used for attaching ceramic brackets for each group (n=15) and cured with LED (Bluephase®) for 50 seconds. Specimens were immersed in distilled water for 24 hours before testing for shear bond at crosshead speed of 1.0 mm/min. The data were analyzed for the differences in bond strength with ANOVA and Tukey’s multiple comparisons (α = 0.05). De-bond surfaces were microscopically examined.ResultsBond strength (MPa) were 12.65±1.14 for EMA5, 14.50±2.21 for EMA15, 13.97±1.17 for EMLE, 12.40±1.95 for PFA5, 15.85±3.13 for PFA15, 14.06±2.17 for PFLE, 12.12±1.54 for EPA5, 15.65±1.57 for EPA15, 12.89±1.17 for EPLE. Significant differences in bond strength among groups were found related to surface treatment (p<0.05), but not significant difference upon type of ceramics (p>0.05). A15 provided higher bond strength than LE and A5 (P<0.05). No damage of ceramic surface upon de-bonding was indicated except for A15 tends to exhibit ditching. LE showed more uniform treated surface for bonding and no surface destruction upon de-bond compared to others.ConclusionsBond strength was affected by surface treatment. Both LE and A15 treated surface provided higher bond strength than A5. Considering possibly inducing defect on ceramic surface, LE seems to provide better favorable surface preparation than others. Treated ceramic surface with Er-YAG prior to bracket bonding is recommended. Key words:Ceramic, ceramic bracket, Er-YAG, laser, shear bond strength, surface treatment.

Effect of Smear Clear and Conventional Root Canal Irrigants on Push-Out Bond Strength of Resilon/Epiphany System.

The aim of the present study is to compare the effect of SmearClear and sodiumhypochlorite (NaOCl), chlorhexidine (CHX) and normal saline (NS) on the push-out bond strength of Resilon/Epiphany system to dentine. In this in vitro study; 48 single-rooted teeth were selected and decoronated from the CEJ. Then the specimens were divided into four groups (n=12). The roots were prepared by single length technique using MTwo rotary system. The final irrigations of the canals were done using 2% CHX, normal saline, 5.25% NaOCl or SmearClear. The canals were obturated by Resilon/Epiphany system. The teeth were cut perpendicular to their longitudinal axis and four 1-mm-thick sections were obtained from coronal and mid root regions. The push-out bond strength of Resilon/Epiphany system to dentin were calculated and bond failure patterns were assessed. The data were subjected to two-way analysis of variance and Tukey's tests. The highest bond strength values were reported for SmearClear and the lowest values for the NS solutions. The effects of irrigant type (P<0.05) and canal area (P<0.0001) on the bond strength of Resilon to dentin were significant (P<0.05). Higher bond strength values were obtained in the mid root areas compared to the coronal regions. In two-by-two comparisons, significant differences in bond strength were found between SmearClear and normal saline (P<0.05) while the other irrigants showed no significant differences (P>0.05). SmearClear solution was able to increase the push-out bond strength of Resilon to the dentin similar to other irrigants (NaOCl and CHX). Therefore, it can be used for the root canal irrigation and smear layer removal in the clinical situations.

Bond strength of a composite resin to glass ionomer cements using different adhesive systems

Abstract Introduction Glass ionomer cements are often used as a base or cavity lining prior to restorative material. Objective To evaluate the bond strength of a composite resin to different glass ionomer cements, when using a two-step conventional and self-etching adhesive systems. Material and method Three glass ionomer cements (Ketac Molar Easymix, Vitremer and Vitrebond), the composite resin Filtek Z350 XT and the adhesive systems Adper Single Bond 2, Clearfil SE Bond and Adper Easy One were used. As negative control, resin was bonded to cement without using an adhesive system. Holes (4 mm diameter, 2 mm deep) prepared in acrilic bloks were filled with the glass ionomer cements (n=12/group). On the surface, an area of 1mm in diameter was delimited, the adhesive system was applied, and a specimen of composite resin with 1 mm height was made. After 24 hours storage (37 °C and 100% humidity), the microshear test was performed. Data were analyzed using two-way ANOVA and Tukey test for comparison between groups (α=0.05). Result The adhesive systems significantly improved the bond strenght of composite resin to glass ionomer cements (p≤0.001). There was no significant difference in bond strength when self-etching adhesive systems were compared with the simplified etch-and-rinse adhesive, except for Vitrebond where Clearfil SE Bond determined higher bond strength when compared to Adper Single Bond 2 (p=0.003). Conclusion Self-etching adhesive systems are a good option for establishing the bond between the composite resin and the glass ionomer cement.

Factors affecting bond development between Ultra High Performance Concrete (UHPC) and steel bar reinforcement

The advent of Ultra High Performance Concrete (UHPC) has led to strong interest in developing new structural applications for the material. While UHPC’s tensile and compression behaviors are relatively well understood, an in-depth analysis of UHPC’s behavior at the component level, specifically the bond strength between UHPC and steel bar reinforcement is lacking and the published data shows large scatter. In the presented study, a series of bar pull out tests was performed in order to characterize the bond strength of a non-proprietary UHPC blend. The tests were conducted using plain and epoxy-coated grade 60bars with nominal diameters of 13mm, 16mm, and 19mm. Other experimental parameters include three development lengths (50, 75 and 100mm), two casting orientations (longitudinal and transverse to the steel bar reinforcement), two steel fiber volume contents (1% and 2%) and early age bond strength at 1, 3 and 7days curing. Results from pull out testing show that bond strength decreases with increased embedment length suggesting a non-uniform distribution of bond strengths. Differences in steel fiber content yielded significant differences in bond strength of up to 36% when using 1% vs. 2% fiber volumes. Early age testing showed that 75% of compressive and bond strength in UHPC is developed within 7days of casting.

Comparison of bracket bond strength to etched and unetched enamel under dry and wet conditions using Fuji Ortho LC glass-ionomer.

Background. Acid etching prior to orthodontic bracket bonding may result in enamel wear or cracks following bracket removal. The manufacturer of Fuji Ortho LC glass-ionomer (GI) claims that it can bond brackets to wet unetched enamel. This study aimed to compare the bracket bond strength to etched and unetched enamel under dry and wet conditions.Methods. In this in vitro study, 60 intact premolar teeth were randomly assigned to 6 groups (etched and dried, etched and moistened with distilled water, etched and moistened with saliva, unetched and dried, unetched and moistened with water, unetched and moistened with saliva). In all the groups, Leon 4 brackets were bonded to the enamel using Fuji Ortho LC GI. The teeth were immersed in distilled water at 37°C for 24 hours and subjected to shear loads at a crosshead speed of 5 mm/min in a Zwick machine for bond strength testing. Data were analyzed with ANOVA, Tukey test and independent t-test.Results. The mean bond strength values in groups 1 (etched, dry), 2 (etched, moistened with water), 3 (etched, moistened with saliva), 4 (unetched, dry), 5 (unetched, moistened with water) and 6 (unetched, moistened with saliva) were 21.86, 16.46, 10.49, 8.12, 9.15 and 9.52 MPa, respectively. Significant differences in bond strength were detected between groups 1 and 2 and all the other groups (P < 0.05), with no significant difference between groups 1 and 2 (P > 0.05).Conclusion. Fuji Ortho LC GI provided adequate bond strength between brackets and enamel. To acquire higher bond strength, brackets must be bonded to etched and dried enamel.

Effects of calcium hydroxide reagent on the bond strength of resin cements to root dentin and the retention force of FRC posts.

The aim of this study was to determine the effects of calcium hydroxide (Ca(OH)2) treatment on bond strength of resin cements to root dentin and retention force of fiber-reinforced composite (FRC) posts. Bovine root dentin was endodontically prepared and treated with Ca(OH)2 for 7 days. Root dentin for bond strength test was adhered to resin-composite with resin cements. For pull-out test, posts consisting of FRC posts and resin-composites were fabricated and cemented to root. Shear bond and pull-out tests were performed using a universal testing machine. No significant differences in bond strength and post retention force were found between Ca(OH)2 treated and untreated groups. Significant differences were found among the cements. A positive correlation was indicated between bond strength of cements and retention force of FRC posts. In conclusion, Ca(OH)2 treatment on root dentin did not affect bond strength of resin cements and retention force of FRC posts.

Evaluation of bond strength between grooved titanium alloy implant abutments and provisional veneering materials after surface treatment of the abutments: An in vitro study

Introduction:Titanium has become the material of choice with greater applications in dental implants. The success of the dental implant does not only depend on the integration of the implant to the bone but also on the function and longevity of the superstructure. The clinical condition that demands long-term interim prosthesis is challenging owing to the decreased bond between the abutment and the veneering material. Hence, various surface treatments are done on the abutments to increase the bond strength.Aim:This study aimed to evaluate the bond strength between the abutment and the provisional veneering materials by surface treatments such as acid etching, laser etching, and sand blasting of the abutment.Materials and Methods:Forty titanium alloy abutments of 3 mm diameter and 11 mm height were grouped into four groups with ten samples. Groups A, B, C, and D are untreated abutments, sand blasted with 110 μm aluminum particles, etched with 1% hydrofluoric acid and 30% nitric acid, and laser etched with Nd: YAG laser, respectively. Provisional crowns were fabricated with bis-acrylic resin and cemented with noneugenol temporary luting cement. The shear bond strength was measured in universal testing machine using modified Shell–Nielsen shear test after the cemented samples were stored in water at 25°C for 24 h. Load was applied at a constant cross head speed of 5 mm/min until a sudden decrease in resistance indicative of bond failure was observed. The corresponding force values were recorded, and statistical analysis was done using one-way ANOVA and Newman–Keuls post hoc test.Results:The laser-etched samples showed higher bond strength.Conclusion:Among the three surface treatments, laser etching showed the highest bond strength between titanium alloy implant abutment and provisional restorations. The sand-blasted surfaces demonstrated a significant difference in bond strength compared to laser-etched surfaces. The results of this study confirmed that a combination of surface treatments and bond agents enhances the bond strength.

Effect of cleaning agent, primer application and their combination on the bond strength of a resin cement to two yttrium-tetragonal zirconia polycrystal zirconia ceramics.

Objective:The objective of this study is to evaluate the effect of a cleaning agent and priming on the bond strength (BS) of a resin cement (RC) to zirconia ceramics after 24 h and 1 year of water-storage.Materials and Methods:Fifty-six Katana and 56 ZirCAD zirconia ceramic plates were prepared and each zirconia brand was divided into four groups (n = 14): (1) untreated; (2) treated with Ivoclean cleaning agent; (3) treated with Monobond Plus coupling agent; (4) treated with Ivoclean + Monobond Plus. Cleaning and coupling agents were applied to zirconia following the manufacturers' instructions. The RC was manipulated, inserted into tubes (0.75 mm diameter/1 mm height) that were positioned on the zirconia surfaces and light activated. Specimens were tested after 24 h and 1 year of water storage. A shear load was applied to the base of the RC cylinders (until failure. Data were analyzed by three-way ANOVA and Tukey tests (α = 5%).Results:No significant difference in BS was noted between zirconia ceramics, except when the combination of cleaning and coupling agents was used. This combination increased the BS for Katana zirconia. One year of water storage leads to a decrease in BS for all experimental groups.Conclusion:The combination of cleaning agent and priming can yield higher BS for Katana at 24 h. BS to zirconia ceramics reduced approximately 50% after 1 year.

Effect of Smear Clear and Some Other Commonly Used Irrigants on dislodgement resistance of Mineral Trioxide Aggregate to Root Dentin.

BackgroundThis study aimed to assess the push-out bond strength of mineral trioxide aggregate (MTA) to root canal dentin after irrigation with Smear Clear in comparison with 2.5% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX) and saline as commonly used root canal irrigants.Material and MethodsThe coronal and mid-root areas of maxillary anterior teeth were horizontally sectioned into one-millimeter thick slices. The root canal lumen of dentinal slices was dilated using a diamond bur with 1.3 mm diameter. After the application of MTA, the samples were incubated in 100% humidity for 10 minutes and were then randomly divided into four groups (n=20) and immersed in Smear Clear, 2.5% NaOCl, 2% CHX and saline for 30 minutes. No irrigant was used for the control group (n=20). A wet cotton pellet was placed on the samples and after 48 hours of incubation, push-out bond strength was measured using a universal testing machine. The samples were evaluated under a stereomicroscope to determine the mode of failure. One-way ANOVA was used to assess statistical differences among the groups.ResultsThe control group showed the highest bond strength with significant differences with other groups (P<0.05). Among the experimental groups, the saline group had no significant difference with CHX (P=0.09) but it had significant differences with Smear Clear and NaOCl groups (P<0.05). No significant difference in bond strength to MTA was noted after irrigation with Smear Clear, CHX and NaOCl (P>0.05). Other pairwise comparisons showed no significant difference (P>0.05).ConclusionsIrrigation with Smear Clear, CHX and NaOCl did not cause a significant change in bond strength of MTA to dentin. Key words:Root Canal Irrigants, push-out, Mineral Trioxide Aggregate, dentin.

Effects of ceramic primers and post-silanization heat treatment on bond strength of resin cement to lithium disilicate-based ceramic

This study evaluated the effect of different ceramic primers and heat treatment of silane coupling agents on bond strength of resin cement to glass ceramic. Five ceramic primers (Clearfil Ceramic Primer/CCP, MonoBond-S, ProSil, RelyX Ceramic Primer and Silano) and one conventional resin cement (RelyX ARC) were tested. Lithium disilicate-based ceramic plates were previously etched with hydrofluoric acid, except for CCP (n = 10). All silane agents were applied to ceramics according to the manufacturer’s instructions and primed ceramics plates were heated (in oven at 100 °C for 1 min) or not before resin cement placement. Dual-cure resin cement was mixed and inserted in tubes (0.75 mm diameter × 1 mm height) that were positioned over primed ceramic surfaces. Micro-shear testing was performed using a universal testing machine. Bond strength data were analyzed using two-way ANOVA and Tukey’s test (5%). Ceramic primer heating did not improve the bond strength of the resin cement to lithium disilicate. Most of ceramic primers did not indicate significant difference in bond strength among them; however, CCP yielded the lowest bond strength among the ceramic primers. In conclusion, when the silane was applied on etched surface the bond strength was higher and heat treatment of silane coupling agents did not affect the bond strength.

Effect of Opaque Porcelain Thickness Bond Strength of Porcelain to Ni-Cr Alloys

Objectives: Metal-ceramic restorations are the standard by which all esthetic restorations are measured. Fracture of dental restorations is a multifactorial problem, which is serious and costly. Debonding of porcelain from the metal substructure and the bond strength depend on many factors. The purpose of this study was to determine whether the opaque porcelain thickness has a significant effect on metal ceramic bond strength utilizing the ISO 9663 standard crack initiation test. Methods: Thirty rectangular Ni-Cr metal bars (25×5×0.3mm) were fabricated according to ISO9663 standards. The metal bars were divided into three groups of 10. Opaque, body and enamel Noritake porcelain were applied on the middle of the bar according to ISO9663 standards up to 1mm porcelain thickness. The opaque porcelain thicknesses were 0.1, 0.2, and 0.3 mm, respectively in the three groups. The 3-point bending test was applied according to the ISO9663 standards and fracture strength (Ffail) was measured using a universal testing machine with a crosshead speed of 1.5mm/minute. Results: Analyses of the data by one-way ANOVA demonstrated no significant differences in bond strength among the three experimental groups (P=0.26). Conclusion: Within the limitations of this study, it is concluded that 0.1mm opaque porcelain provides sufficient bond strength between metal and ceramic in metal-ceramic restorations.

MODERN VIEW OF THE COMBINED USE OF COMPOSITE MATERIAL AND GLASS IONOMER CEMENT

The adhesion of resin-modified glass-ionomer (RMGI) to composite resin plays a very important role in the durability of sandwich restorations. Aim - to explore that co-curing RMGIC and composite resin to GIC using self-etch adhesives and bulk-fill materials may create a chemical bond and improve the bond strengths between these two materials. Materials and methods. Twenty specimens were prepared on gypsum blocks, with wells prepared in them by drilling holes, to retain the RMGIC. The specimens were randomly divided into two groups of 10 specimens each. In group I, after etching and rinsing the surface of cement, a thin layer of an adhesive, which was a Total-Etch type, was applied between RMGIC and the composite resin. In group II, the stage of etching was missed, a Self-Etch adhesive and a thin layer of bulk fill material were applied on the cement surface. Then after curing all the specimens, the shear bond strength was measured using a Bisco Shear bond testing machine. Failure mode was assessed under a stereomicroscope. Results. There were statistically significant differences in bond strengths between the groups (P&lt; 0.05). Failures were predominantly of the cohesive type in all the groups. Conclusion. Based on the results of this study, the use of self-etch adhesive resin on the unset glass-ionomer and using bulk-fill material yielded the highest bond strength in the combined use of glass-ionomer cement and composite material.

Effect of Sonic Application of Universal Adhesive Systems on Bond Strength of Fiber Posts to Root Canal.

This study evaluated the push-out bond strength (BS) of fiber posts in root canals and the nanoleakage (NL) pattern at the bonding interface when universal adhesives were applied in etch-and-rinse mode to root dentin using an oscillating sonic device. Fifty-four roots of human premolars were endodontically prepared and divided into 6 experimental groups according to the main factors: adhesive system/resin cement (Ambar Universal/AllCem, Scotchbond Universal/RelyX ARC, Prime&Bond Elect/Enforce) and application mode (vigorous manual or sonic). Fiber posts were cemented and roots were transversally sectioned into six 1-mm-thick serial slices, which were subjected to BS testing (n = 7 per group) at a crosshead speed of 0.5 mm/min, and the rest (n = 2 per group) were subjected to NL analysis using scanning electron microscopy after slice immersion in silver nitrate. Data were analyzed using two-way ANOVA and Bonferroni's post-hoc test (α = 5%). Sonic application significantly increased BS only on the coronal third when Ambar Universal was used. When Scotchbond Universal was used, higher BS was observed when the adhesive was manually applied than when the sonic device was used. For Prime&Bond Elect, no significant difference in BS was noted when the application methods were compared. Manual application also produced lower NL values than did sonic application when Ambar Universal was used, while no significant difference in NL was noted using the other adhesive systems. Sonic application did not improve the bond strength of posts in root canals in comparison to vigorous, manual application.

Effects of application mode of self-etching primer on shear bond strength of orthodontic brackets

ObjectivesTo compare the effects of application mode of one self-etching adhesive on the shear bond strength of metallic orthodontic brackets. MethodsSeventy-five healthy bovine incisors were divided into 5 groups (n=15). The self-etching primer (Transbond Plus, 3M Unitek) was applied on the enamel actively and passive for 0 (control), 5 and 10s, followed by air jet application and light cured for 10s (600mW/cm2). The metal brackets were bonded with adhesive (Transbond XT) and light cured for 20s each proximal surface (mesial and distal). The shear bond strength was determined after water storage at 37°C for 24h. The specimens were tested using a universal testing machine (Instron 3342). Once debonded, each specimen was examined to identify the failure mode. The bond strength data were subjected to One-way Anova and Tukey tests (α=0.05) and failure mode data were analyzed by Kruskal–Wallis test (α=0.05). ResultsNo significant difference in bond strength was found between 5 groups. Increasing the application time and applying agitation of self-etching primers did not affect the shear bond strength (p=0.487). There were no differences between failure mode values in all tested groups (p=0.88) and score 1 was predominant. ConclusionsThe shear bond strength of the self-etching adhesive is not influenced by the application mode.

Effect of Repeated Firings on Microtensile Bond Strength of Bi-layered Lithium Disilicate Ceramics (e.max CAD and e.max Press)

To achieve acceptable contour, color, esthetics, and occlusal relations, the porcelain may be subjected to several firing cycles. This study sought to assess the effect of multiple firing cycles on the microtensile bond strength (MTBS) of lithium disilicate-based ceramics (e.max Press, e.max CAD). IPS e.max computer aided design (CAD) cores were fabricated using CAD/(Computer Aided Manufacturing (CAM)) technology, and IPS e.max Press cores were fabricated using the heat-pressing technique (12 × 12 × 4 mm(3)). Cores in each group were divided into three subgroups based on the number of firing cycles (three, five, and seven cycles). After porcelain application, the samples were sectioned into microbars and a total of 20 sound microbars in each group were subjected to tensile load in a microtensile tester at a crosshead speed of 1 mm/minute. Microtensile bond strength of the core to the veneering porcelain was analyzed using one-way analysis of variance (ANOVA). Pairwise comparisons were made using the Tukey's test (p < 0.05). In the e.max CAD, the mean MTBS values were 22.07 ± 6.63, 34.68 ± 7.07, and 26.05 ± 10.29 MPa following three, five, and seven firing cycles respectively. These values for the e.max Press were 34.46 ± 9.28, 23.09 ± 5.02, and 31.26 ± 12.25 MPa respectively. There was significant difference in bond strength of e.max CAD (p < 0.003) and e.max Press (p < 0.002) based on the number of firing cycles. Increasing the number of porcelain firing cycles decreased the bond strength of the core to the veneering porcelain in both ceramics. It is better to decrease the number of firing cycle as much as possible.

Orthodontic bracket bonding to glazed full-contour zirconia.

ObjectivesThis study evaluated the effects of different surface conditioning methods on the bond strength of orthodontic brackets to glazed full-zirconia surfaces.Materials and MethodsGlazed zirconia (except for the control, Zirkonzahn Prettau) disc surfaces were pre-treated: PO (control), polishing; BR, bur roughening; PP, cleaning with a prophy cup and pumice; HF, hydrofluoric acid etching; AA, air abrasion with aluminum oxide; CJ, CoJet-Sand. The surfaces were examined using profilometry, scanning electron microscopy, and electron dispersive spectroscopy. A zirconia primer (Z-Prime Plus, Z) or a silane primer (Monobond-S, S) was then applied to the surfaces, yielding 7 groups (PO-Z, BR-Z, PP-S, HF-S, AA-S, AA-Z, and CJ-S). Metal bracket-bonded specimens were stored in water for 24 hr at 37℃, and thermocycled for 1,000 cycles. Their bond strengths were measured using the wire loop method (n = 10).ResultsExcept for BR, the surface pre-treatments failed to expose the zirconia substructure. A significant difference in bond strengths was found between AA-Z (4.60 ± 1.08 MPa) and all other groups (13.38 ± 2.57 - 15.78 ± 2.39 MPa, p < 0.05). For AA-Z, most of the adhesive remained on the bracket.ConclusionsFor bracket bonding to glazed zirconia, a simple application of silane to the cleaned surface is recommended. A zirconia primer should be used only when the zirconia substructure is definitely exposed.

Effect of thermocycling on the durability of etch-and-rinse and self-etch adhesives on dentin.

The objective was to compare bond strengths of adhesives with/without thermocycling and to analyze the micromorphology of resindentin interfaces. Flat dentin surfaces were prepared and divided into eight groups to bond with four etch-and-rinse adhesives (Optibond FL, Adper Scotchbond Multi-Purpose, Optibond Solo Plus, and Single Bond 2) and four self-etch adhesives (Clearfil SE Bond, Adper SE Plus, Clearfil S(3) Bond and Adper Easy Bond). Specimens were further divided into two subgroups subjected for with/without thermocycling and then subjected to both micro-tensile test and resin-dentin interface evaluation. The results revealed that there were significant differences in bond strength between the groups with and without thermocycling for all etch-and-rinse groups and for the Adper Easy Bond self-etch group (p<0.01). Clearfil SE Bond demonstrated highly durable bond strengths. Furthermore, more silver ion uptake was observed at the resin-dentin interfaces for all etch-and-rinse adhesives and Adper SE Plus and Adper Easy Bond after thermocycling.

Adhesive systems for restoring primary teeth: a systematic review and meta-analysis of invitro studies.

To systematically review the literature for invitro studies that evaluated the immediate or after ageing bond strength of etch-and-rinse and self-etch adhesive systems to enamel and dentin of primary teeth. The search was conducted in PubMed/MEDLINE, Cochrane, SciELO, Lilacs, and Scopus databases with no publication year or language limits, following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement. From 459 potentially eligible studies, 39 were selected for full-text analysis, and 5 were identified in reference lists, with 36 considered in the meta-analysis. Two reviewers independently selected the studies, extracted the data, and assessed the risk of bias. Pooling bond strength data was calculated using random effects analysis method, comparing two categories of adhesives (etch-and-rinse versus self-etch systems) when applied in different types and conditions of substrate (α = 0.05). No statistical significant difference in bond strength between both categories was observed in caries-affected dentin at immediate evaluation and in sound dentin after ageing. Etch-and-rinse adhesives, however, performed better in sound enamel and dentin substrates considering immediate bond strength. None study assessed the long-term adhesive effectiveness to sound or demineralized enamel. Although the articles included in this meta-analysis showed high heterogeneity and high risk of bias, the invitro literature suggests superior performance of etch-and-rinse adhesives in primary teeth in comparison with self-etch systems.