Surface Conditioning Treatments Research Articles

Effect of different surface conditioning methods and low pH solutions on the shear bond strength of orthodontic brackets to newly introduced CAD/CAM materials

AimTo evaluate the shear bond strength (SBS) of ceramic and metallic orthodontic brackets bonded to lithium disilicate ceramics or hybrid ceramics and subjected to different surface conditioning treatments. Materials and methodsIn total, 300 specimens were fabricated from GC LiSi (lithium disilicate) and GC Cerasmart (hybrid) ceramic blocks. The specimens were divided into four groups according to the following surface treatments: hydrofluoric acid (HF); sandblasting with 50 μm aluminum oxide; Monobond Etch and Prime; and erbium-doped yttrium aluminum garnet (Er-YAG) laser. Metal (Victory Series) and ceramic (Clarity) brackets were bonded using an orthodontic adhesive resin (Transbond XT; 3M Unitek, CA, USA). The specimens were then stored in three different mediums (artificial saliva, mouth rinse, and gastric juice) and thermocycled. An SBS test was performed after 1 week. The surface morphology was examined after the conditioning treatments using a scanning electron microscope. Data were analyzed using analysis of variance, t-test, and Duncan test. ResultsThe SBS data revealed that the type of computer-aided design/computer-aided manufacturing (CAD/CAM) block and surface conditioning method significantly affected the SBS. The highest SBS was recorded (10.112 MPa) for the HF-treated hybrid ceramic blocks stored in the saliva medium, while the lowest SBS (1.862 MPa) was reported for the Er-YAG laser-treated lithium disilicate ceramic blocks stored in the gastric juice medium. GC Cerasmart exhibited better bond strength than that of GC LiSi; however, no significant difference was observed between the ceramic and metal brackets. ConclusionThe CAD/CAM material, surface conditioning method, and medium affect the SBS.

Inhibition of bacterial adherence on stainless steel coupons by surface conditioning with selected polar lipids

AbstractPolar lipids were recently found to have the surfactant property that could interfere with the bacterial adherence process during biofilm formation, a promising effect against the bacterial contamination on food processing surfaces. This study aimed to investigate the effect of surface conditioning of polar lipids such as phosphatidylcholine and sphingomyelin on stainless steel surfaces and subsequently on bacterial adherence. A confocal laser scanning microscope was used to examine formed conditioning layers and bacterial adherence. The thinnest conditioning layer was created by dilute skim milk and by sphingomyelin, while thicker layers were created by phosphatidylcholine, dilute buttermilk, and butter serum. Among surface conditioning treatments of stainless steel coupons, those performed with diluted buttermilk, butter serum, and polar lipids such as phosphatidylcholine, and sphingomyelin were able to scale down the adherence of Lactococcus lactis subsp. lactis NBRC 100676 and Leuconostoc mesenteroides subsp. cremoris NBRC 102479 compared to the surface conditioning with dilute skim milk. For both strains, the higher the phosphatidylcholine concentration (over 0.01%) and the longer the adhesion time (over 12.0 h), the more the adherence‐reducing ability of conditioned surfaces. The higher the sphingomyelin concentration used in surface conditioning, the higher the adherence‐reducing activity on stainless‐steel surfaces was at all adhesion times (0.5, 12.0, and 24.0 h). Our results suggested that, for short bacterial exposure period (0.5, 12.0, and 24.0 h), dilute buttermilk, butter serum, and individual polar lipids may have a bacterial adherence‐reducing effect, and can potentially be used for reducing biofilm formation.

Comparison of shear bond strength of resin cements to IPS empress 2 ceramic under four surface conditioning treatments: An in vitro study

1. To evaluate and compare the shear bond strength of four resin cements to IPS Empress 2 ceramic under four surface treatment conditions. 2. To compare the shear bond strength of light cure and Dual cure resin cements to IPS Empress 2 ceramic under four surface treatment conditions. Materials and Methods: The resin cements used in the study were Rely XTM veneer cement - light cure, Variolink II light cure and dual cure and Calibra dual care. The ceramic surface treatments were 1. Abrasion with 600 grit silicone carbide paper 2. Etching with 9.5% hydrofluoric acid for four minutes 3. Treating with silane for one minute and 4. Combination of etching and silane application. The ceramic used in the study was IPS Empress 2. Results: One-way ANOVA of shear bond strength of resin cements showed hydrofluoric acid etching followed by silane application produced bond strength in the highest statistical group and there were no significant differences among the four cements when hydrofluoric acid etching was followed by silane application. One way ANOVA of shear bond strength of light cure and dual cure resin cements showed that the dual cure resin cements showed higher bond strength. Conclusion: Within the limitation of the study hydrofluoric acid etching followed by silane produced the best bond with the four resin cements. The dual cure resin cements produced higher bonds strength to ceramic.

Repair strength and surface topography of lithium disilicate and hybrid resin ceramics with LLLT and photodynamic therapy in comparison to hydrofluoric acid.

The aim was to compare the repair bond strength and surface topography of lithium disilicate ceramics (LDC) and hybrid resin ceramics (HRC) using different surface conditioning treatments [low level laser therapy (LLLT), photodynamic therapy (PDT), hydrofluoric acid (HF) with silane and air abrasion (AA) and silane]. Sixty specimens each of LDC and HRC were used. Discs were prepared for each group (6 × 2 mm), conditioned using different regimes. Specimens in group 1 and 5 were laser irradiated using Er,Cr:YSGG (ECYL), group 2 and 6 were conditioned using methylene blue photosensitizer (PDT), group 3 and 7 surface was treated with hydrofluoric acid and silane (HFA-S), group 4 and 8 conditioned with Al2O3 air abrasion and silane (AA-S). A Porcelain Repair Kit was used according to manufacturer recommendation in all samples. Peak universal bond adhesive was rubbed on ceramic surface and then bonded with composite resin. For shear bond strength testing the specimens were placed in a universal testing machine. A stereomicroscope at 40x magnification was used to analyse failure pattern. Five specimens in each group after surface treatment were evaluated for surface changes and topography using scanning electron microscopy. The mean repair bond strength was calculated using ANOVA and Tukey's post hoc test at a significance level of (p < 0.05). The highest repair bond strength was observed in group 3 (LDC) (20.57 ± 3.58 MPa) (HFA-S), whereas, the lowest score was displayed in Group 2 (LDC) using methylene blue photosensitizer (MBPS) (12.18 ± 1.08 MPa). Similarly, in HRC the highest repair SBS was presented in group 8 (AA-S) (20.52 ± 2.51 MPa) and the lowest SBS values were exhibited by PDT treated group 6 (13.22 ± 0.62 MPa). A combination of mechanical and chemical surface treatments should be used in order to achieve adequate repair bond strength between resin composites and ceramic interface of LDC and HRC.

Lithium di silicate ceramic surface treated with Er,Cr:YSGG and other conditioning regimes bonded to orthodontic bracket

AimTo assess bond integrity and modes of failure of metallic brackets to lithium disilicate ceramics (LDC) conditioned with Er,Cr:YSGG laser (ECL). Material and methodsSixty LDC were arbitrarily allocated into six groups (n = 15) according to the type of ceramic surface conditioning treatment. Group 1 surface treated with silane (S) only, group 2 surface etched with hydrofluoric acid (HF)+ S, group 3 surface conditioned with HF+ ultrasonic bath (UB)+ S, group 4 sand blasting (SB) of glass ceramic surface with 50 µm Al2O3, group 5 surface conditioned with self-etch ceramic primer (SECP) and in group 6 surface treated with ECL + S. After conditioning, the specimens were positioned in a universal testing device for shear bond strength (SBS) testing. Adhesive Remnant Index (ARI) was used to determine sites of bond failure. Among experimental groups analysis of variance (ANOVA) and Tukey multiple comparison test was used at a significance level of (p < 0.05). ResultsThe highest SBS values were observed in group 3 HF+ UB + S (18.21 ± 1.241) and the lowest SBS values were displayed group 1 surface treated with S only (5.21 ± 0.23). Specimens surface conditioned in group 2 with HF+ S (17.85 ± 1.25), group 3 HF+ UB + S (18.21 ± 1.241) and group 6 ECL + S (17.09 ± 1.114) unveiled comparable SBS values (p > 0.05). ConclusionLDC conditioned with ECL at (4.5 W and 30 Hz) has a potential to be used in clinical settings alternate to HF acid.

Influence of phototherapy on adhesive strength and microleakage of bleached enamel bonded to orthodontic brackets: An in-vitro study.

The aim of the present in-vitro study was to explore bleached enamel reversal with phototherapy (Er,Cr:YSGG) when using two dissimilar bonding system to bond brackets on microleakage and shear bond strength. Amongst one twenty samples, ninety samples were bleached using 35% hydrogen peroxide. After the bleaching procedure, the teeth were randomly divided into three groups according to surface conditioning treatment (n = 30 each). Group 1: treated with Er,Cr:YSGG (ECL) Group 2: 10% sodium ascorbate (SA) and Group 3: Bleached only (BO). Based on the type of adhesive, specimens were further classified into eight subgroups. In subgroup 1,2,3 and no treatment (NT) (n = 15) adhesive Transbond XT was applied on already etched surface and these subgroups were named as NT-TEP, BO-TEP, ECL-TEP and SA-TEP. Similarly, in subgroup 5,6,7 and NT specimens (n = 15) were conditioned with Transbond Plus self-etching primer and these subgroups were named as NT-SEP, BO-SEP, ECL-SEP and SA-SEP. Samples from each subgroup were exposed to increasing load for evaluation of shear bond strength. Microleakage among subgroups were tested by immersing samples in Methylene blue prior one day. Analysis of variance and Tukey multiple comparisons test was used to assess data. The maximum and minimum bond strength was observed in group NT-TEP [17.14(2.54)] and BO-SEP [6.14(0.215)] respectively. Samples conditioned with phototherapy ECL-TEP [16.14(1.231)] exhibited comparable bond strength to specimens conditioned with sodium ascorbate (SA-TEP) [16.72(1.298)]. Similarly, bond strength values of ECL-SEP [13.43(0.921)] and SA-SEP were comparable. The highest microleakage score was demonstrated in BO-SEP [83.21(38.21)] whereas, the lowest microleakage scores were displayed in NT-TEP [23.73(13.45)]. Er,Cr:YSGG phototherapy reversal on bleached enamel with etch and rinse adhesives has a potential to be used in clinical settings alternate to conventional sodium ascorbate when bonding orthodontic brackets.

Effect of phototherapy on dentin bond strength and microleakage when bonded to resin with different conditioning regimes.

To assess the efficacy of phototherapy on bond strength and microleakage of bulk fill composites in comparison to conventional dentin surface treatments. Ninety human third molars were divided into 3 groups (n = 30 each) according to surface conditioning treatment. Group 1 (Etch and Bond) EB, group 2 was treated with Er,Cr: YSGG (ECL) and group 3 was treated with a diode laser (DL). Based on the type of bulk fill resin composite, samples were divided into six sub-groups. In sub-group 1, 2 and 3 (n = 15) build-up was done using ZirconCore (ZC) and these subgroups were named as EB-ZC, ECL-ZC and DL-ZC. In subgroup 4,5,6 (n = 15) MulticCore Flow (MC) was used for core build-up and these subgroups were named as EB-MC, ECL-MC, DL-MC. For shear bond strength (SBS) all the samples were exposed to loads using a universal testing machine. Five samples each from all subgroups were immersed in methylene blue dye for 24 h prior to microleakage testing. Data were assessed using analysis of variance and Tukey multiple comparisons test. Among all the groups the lowest bond strength was achieved in DL-ZC [10.45(0.459)]. Similarly, the highest bond strength was attained in EB-MC[17.84(0.925)]. The highest microleakage scores amongst different group was exhibited in DL-ZC [82.45(39.459)] whereas, the lowest microleakage scores were displayed in EB-MC [31.21(15.92)]. Phototherapy in the form of Er,Cr:YSGG laser showed comparable adhesive bond outcomes to conventional etch and bond dentin conditioning techniques. Moreover, Multicore bulk fill material showed better bond strength and microleakage scores than zirconium particle infiltrated bulk fill composite in the presence of dentin phototherapy.

The effect of root surface conditioning on smear layer removal in periodontal regeneration (a scanning electron microscopic study)

The role of root surface conditioning treatment on smear layer removal of human teeth is affected by periodontitis in periodontal regeneration. The objective of this study is to analyze the smear layer on root surface conditioned with 2.1% minocycline HCl ointment (Periocline), and 24% EDTA gel (Prefgel). A total of 10 human teeth indicated for extraction due to chronic periodontitis were collected and root planed. The teeth were sectioned in thirds of the cervical area, providing 30 samples that were divided into three groups – minocycline ointment treatment, 24% EDTA gel treatment, and saline as a control. The samples were examined by scanning electron microscope. No significant differences in levels of smear layer were observed between the minocycline group and the EDTA group (p=0.759). However, there were significant differences in the level of smear layer after root surface treatment in the minocycline and EDTA groups, compared with the control group (p=0.00). There was a relationship between root surface conditioning treatment and smear layer levels following root planing.

Resina fluida autoadhesiva utilizada como sellante de fosas y fisuras. Estudio de microinfiltración

AimTo evaluate the sealing ability of a self-adhesive flowable composite-resin (Fusio Liquid Dentin, Pentron Clinical) with different conditioning treatments of the enamel surface used as a fissure sealant. Materials and Method140 recently extracted human third molars were selected and randomly divided into four groups (n=35). Each group received an enamel conditioning treatment and a sealant application. The following groups were established: Group 1, acid etching and sealant application (Clinpro, 3M ESPE); Group 2, acid etching and self-adhesive flowable composite-resin (Fusio Liquid Dentin, Pentron Clinical); Group 3, self-adhesive flowable composite-resin; Group 4, sandblasting and self-adhesive flowable compositeresin. Sealed teeth were thermocycled (500 cycles, 5-55°C) and immersed in ammoniacal silver nitrate solution for 24h (ph=14). After that, the teeth were immersed in radiographic developer solution (GBX, Kodak) for 8h. Then, the teeth were vertically sectioned to obtain two slides each that were observed under magnification (4x) and digitally analyzed to assess microleakage and sealant penetration. Results were statistically analyzed (ANOVA, Dunnett, p<0.05). ResultsMicroleakage of Group 1 (13.18±9.25%) was significantly lower than groups 2, 3 and 4 (p<0.05). Group 1 had the highest sealant penetration mean (98.92±2.77%). ConclusionFusio Liquid Dentin had a worse sealing ability than Clinpro irrespective of their enamel conditioning treatment when used as a fissure sealant. Among Fusio's groups, acid etching was the best enamel surface conditioning treatment.

In Vitro Microleakage of Biodentine as a Dentin Substitute Compared to Fuji II LC in Cervical Lining Restorations

1) To evaluate the marginal sealing efficacy of Biodentine at the cervical margins of approximal cavities placed in molars; 2) to evaluate and compare the use of Biodentine in combination with resin-based adhesives and a resin composite, compared with a resin-modified glass-ionomer cement (Fuji II LC). Sixty approximal cavities were prepared on mesial and distal surfaces of 30 extracted human third molars. The teeth were randomly assigned into 6 groups of 10 cavities each: (G1) Biodentine, (G2) Fuji II LC as a filling material, (G3) Biodentine as a base + Optibond Solo Plus + silane + Filtek Z250, (G4) as in G3 without silane, (G5) Biodentine as a base + Septobond SE + Filtek Z250, (G6) Fuji II LC as a base + Optibond Solo Plus + Filtek Z250. The materials were applied according to the manufacturers' instructions. Biodentine required no dentin or enamel surface conditioning treatment. The teeth were thermocycled 2500x (5°C to 55°C). The specimens were then sealed with a 1-mm window around the marginal interface. Samples were immersed in a 50% w/v silver nitrate solution and exposed to a photo developing solution. The teeth were embedded in resin (Sody 33) and sectioned through the restorations. The silver penetration was directly measured using a light microscope. The results were expressed as ordinal scores from 0 to 3 at cervical, interfacial, and enamel margins. The data were analyzed with the nonparametric Kruskal-Wallis, Games Howell, and Wilcoxon signed rank tests (p < 0.05). No statistically significant differences were found between the 6 groups, neither for the dentin cervical margins nor for cervical lining (Biodentine or Fuji II LC)/resin composite interfaces. Statistically significant differences were observed between G5 (median score = 2.0) and the other groups (median score = 1.0) for the enamel margins. Statistically significant differences were found between enamel and dentin cervical margins in G2 (enamel median score = 1.0; dentin median score = 1.5) and G5 (enamel median score = 2.0; dentin median score = 1.0). Within the limits of this in vitro study, Biodentine as dentin substitute in cervical lining restorations or as a restorative material in approximal cavities when the cervical extent is under the CEJ seems to perform well without any conditioning treatment. However, the operating time is longer than when a RMGIC (Fuji II LC) is used.

Effect of silica coating on fracture strength of glass-infiltrated alumina ceramic cemented to dentin.

To examine the availability of sol-gel processed silica coating for alumina-based ceramic bonding, and determine which silica sol concentration was appropriate for silica coating. Sixty disks of In-Ceram alumina ceramic were fabricated and randomly divided into 5 main groups. The disks received 5 different surface conditioning treatments: Group Al, sandblasted; Group AlC, sandblasted + silane coupling agent applied; Groups Al20C, Al30C, and Al40C, sandblasted, silica coating via sol-gel process prepared using 20 wt%, 30 wt%, and 40 wt% silica sols, and then silane coupling agent applied. Before bonding, one-step adhesives were applied on pre-prepared ceramic surfaces of all groups. Then, 60 dentin specimens were prepared and conditioned with phosphoric acid and one-step adhesive. Ceramic disks of all groups were cemented to dentin specimens with dual-curing resin cements. Fracture strength was determined at 24 h and after 20 days of storage in water. Groups Al20C, Al30C, and Al40C revealed significantly higher fracture strength than groups Al and AlC. No statistically significant difference in fracture strength was found between groups Al and AlC, or among groups Al20C, Al30C, and Al40C. Fracture strength values of all the groups did not change after 20 days of water storage. Sol-gel processed silica coating can enhance fracture strength of In-Ceram alumina ceramic after bonding to dentin, and different silica sol concentrations produced the same effects. Twenty days of water storage did not decrease the fracture strength.

Surface studies of niobium chemically polished under conditions for superconducting radio frequency (SRF) cavity production

The performance of niobium superconducting radiofrequency (SRF) accelerator cavities is strongly impacted by the topmost several nanometers of the active (interior) surface, especially as influenced by the final surface conditioning treatments. We examined the effect of the most commonly employed treatment, buffered chemical polishing (BCP), on polycrystalline niobium sheet over a range of realistic solution flow rates using electron back scatter diffraction (EBSD), stylus profilometry, atomic force microscopy, laboratory XPS and synchrotron (variable photon energy) XPS, seeking to collect statistically significant datasets. We found that the predominant general surface orientation is (1 0 0), but others are also present and at the atomic-level details of surface plane orientation are more complex. The post-etch surface exhibits micron-scale roughness, whose extent does not change with treatment conditions. The outermost surface consists of a few-nm thick layer of niobium pentoxide, whose thickness increases with solution flow rate to a maximum of 1.3–1.4 times that resulting from static solution. The standard deviation of the roughness measurements is ±30% and that of the surface composition is ±5%.

Low-temperature SCR of NO x with NH 3 over activated carbon fiber composite-supported metal oxides

In previous works, the authors were involved in the preparation and optimization of Nomex-based activated carbon fibers (ACFs) monoliths and their use as catalytic supports of manganese oxides for the selective catalytic reduction (SCR) of NO x with NH 3 at low temperature. Thus, a low density monolith made of carbonized Nomex™ rejects was fabricated and submitted to different surface conditioning treatments in order to maximize the dispersion and loading of manganese oxides which were highly active in the SCR process. In order to complete the study, in this work different carbon fibers were used to fabricate the monolithic support, and the catalytic activity of the derived manganese oxide-based catalysts was analyzed and compared to that of the standard Nomex™-supported catalyst. These fibers were coal Pitch-, Rayon-, PAN-, and phenolic Resin-based carbon fibers. Additionally, catalysts based on other metal oxides (nickel, chromium, vanadium and iron) were prepared via equilibrium adsorption (EA) and pore volume impregnation (PVI) of the strategically modified supports, in an attempt to surpass the catalytic performance of the already highly active manganese oxide-based catalysts and to tackle one of the main drawbacks for the utilization of these catalysts under practical conditions; the SO 2 deactivation. For all the prepared catalysts the following parameters were evaluated at a standard reaction temperature of 150 °C: catalytic activity, selectivity, extent of support gasification, H 2O inhibition and SO 2 deactivation. Additionally temperature programmed desorption (TPD) of NO was conducted on specific samples in order to analyze the different adsorption modes of NO on the catalyst surface. All this research procedure has eventually derived in the selection of a catalyst (Nomex™ rejects-based activated carbon fiber composite (ACFC) supported iron oxides) which constitutes a compromise between high catalytic performance and moderate SO 2 deactivation.

Shear bond strength of resin cements to both ceramic and dentin

Statement of Problem. All ceramic restorations benefit from resin cement bonding to the tooth. However, the literature is unclear on which cement, ceramic conditioning treatment, and dentin bonding agent produce the highest and longest-lasting bond strength. Purpose. This in vitro study evaluated immediate and 6-month shear bond strengths between a feldspathic ceramic and 4 different resin cements with the use of 6 different surface-conditioning treatments. Shear bond strengths between the 4 resin cements and dentin also were measured. Material and Methods. Four hundred eighty discs (10 mm in diameter and 4 mm thick) of Ceramco II porcelain were randomly divided into 6 main groups (n = 80). The ceramic specimens received 6 different surface conditioning treatments before the application of resin cement. These surface treatments were sanding with 600-grit silicon carbide paper, microetching with aluminum oxide, sanding followed by silane application, microetching followed by silane application, hydrofluoric acid-etching, and hydrofluoric acid-etching followed by silane application. Each group then was subdivided into 4 subgroups (n = 20) for the application of 1 of 4 cements: Nexus, Panavia 21, RelyX ARC, and Calibra. All cemented specimens were tested under shear loading until fracture on a universal testing machine; the load at fracture was reported in MPa as the bond strength. Bond strengths were determined at 24 hours and after 6 months of specimen storage in a saline solution. For dentin-resin cement shear bond strength testing, dentin specimens were treated with dentin bonding agents, and a thin layer of resin cement was applied according to the manufacturer's directions. Prodigy composite was bonded to the cement. Shear bond strengths were determined as above and reported in MPa at fracture. Data were analyzed with 3-way analysis of variance (P<.01). Results. Hydrofluoric acid-etching followed by silane application produced bond strengths (15.0 ± 7.4 to 21.8 ± 5.8 MPa) in the highest statistical group with all 4 cements at both 24 hours and 6 months (P<.01). Sanding with 600-grit silicon carbide paper and microetching with aluminum oxide produced the lowest bond strengths (0.0 to 4.0 ± 3.5 MPa). At 24 hours and 6 months, there were no significant differences among the 4 cements when hydrofluoric acid-etching was followed by silane application. Both auto- and light-polymerized dentin bonding agents bonded better to dentin than dual-polymerized bonding agents. Conclusion. Within the limitations of this study, hydrofluoric acid-etching followed by silane application produced the best bonds at 24 hours and 6 months with all 4 cements. Auto- and light-polymerized adhesives were associated with higher bond strengths to dentin than dual-polymerized adhesives. (J Prosthet Dent 2002;88:277-84.)

Aluminium cathode effects in zinc electrowinning from industrial acid sulphate electrolyte

The effects of aluminum cathode grain size and surface conditioning treatments on zinc electrodeposition from purified industrial acid sulphate electrolyte were investigated. The Al cathode grain size had no effect on the long-time (15–60 min) deposit characteristics although deposits obtained using large-grain Al cathodes were often easier to strip. A study of the initial zinc nucleation (5–80s) showed that fine-grain Al cathodes had more zinc nucleation sites than largegrain cathodes. The influence of cathode preconditioning and glue on the initial zinc nucleation were also determined.

Conditioning Aluminum Alloys for Electroplating

Successful use of the zinc immersion process for plating aluminum alloys is dependent on the effectiveness of the surface conditioning treatments used prior to the immersion zinc dip. Various conditioning treatments are described for removing constituents that may cause difficulty during plating and for obtaining a uniform and active surface for deposition of the zinc layer. The manner in which the conditioning treatments and variations in the zinc immersion layer may affect the performance of plated aluminum alloys is described.