Surface Conditioning Methods Research Articles

Adhesion to zirconia used for dental restorations: a systematic review and meta-analysis.

Currently, no consensus exists regarding the best adhesion protocol for zirconia used in dentistry; this is important particularly for restorations where mechanical retention is deficient. This systematic review analyzed the adhesion potential of resin-based and glass-ionomer luting cements to zirconia and aimed to highlight the possible dominant factors affecting the bond strength results to this substrate. Original scientific papers on adhesion to zirconia published in the MEDLINE (PubMed) database between 01/01/1995 and 01/06/2011 were included in this systematic review. The following MeSH terms, search terms, and their combinations were used: "Dental bonding", "Zirconium", "Zirconia", "Y-TZP", "Y-TZP ceramic", "Materials Testing/methods", "Test", "Cement", and "Resin bonding". Two reviewers performed screening and data abstraction. Descriptive statistics were performed and the frequencies of the studied parameters, means, standard deviations, confidence intervals (95% CI; uncorrected and corrected), median values, and interquartile ranges (IQR) were calculated for the bond strength data reported for different factor levels: surface conditioning methods (control, physicochemical, physical, chemical), cements (bis-GMA-, MDP-, and 4-META-based resin cements, self-adhesive cements, glass ionomer), aging with and without thermocycling (TC), and test methods (macroshear, microshear, macrotensile, and microtensile). The final search provided 177 titles with abstracts. Further abstract screening yielded 72 articles, out of which 54 were found potentially appropriate to be included. After full text evaluation, 2 of these were eliminated. The selection process resulted in the final sample of 52 studies. In total, 169 different surface conditioning methods, mainly combinations of air-abrasion protocols and adhesive promoters (primers or silanes), were investigated. Altogether, the use of 5 types of cements and 4 testing methods was reported. While 26 studies were performed without TC as aging, 26 of them employed thermocycling at varying number of cycles. This review highlighted that adhesion of the luting cements is significantly influenced by the surface conditioning method (p = 0.044), cement type (p = 0.018), test method (p = 0.017) and aging condition (p = 0.003). In nonconditioned control groups without thermocycling, mean bond strength values ranged between 1.15 (IQR = 3.54) and 8.93 (IQR = 9), and 6.9 (IQR = 0) and 8.73 (IQR = 13.93) MPa for macroshear and macrotensile tests, respectively. After physical conditioning method, MDP monomer based cement presented the highest bond values compared to those of other resin cements using either the macrotensile (no TC: 34.2; IQR = 24.18 MPa, TC: 42.35; IQR = 0 MPa) or microtensile (no TC: 37.2; IQR = 41.5 MPa, TC: 17.1; IQR = 31.15 MPa) test method. Based on the results of this systematic review, increased adhesion could be expected after physicochemical conditioning of zirconia. MDP-based resin cements tend to present higher results than those of other cements types when tested using macro- and microtensile tests. Adhesion studies on zirconia and reporting of data require more standardization.

Shear bond strength of a self-etched resin cement to an indirect composite: Effect of different surface treatments

The aim of this study was to compare the shear bond strength of resin cement (Rely X-U200) bonded to differently conditioned indirect composite samples. Sixty-six composite resin specimens (5 mm in diameter and 3 mm in thickness) were prepared with an indirect composite resin (Grandia) and randomly divided into six groups. Surfaces of the samples were treated with one of the following treatments; %37 phosphoric acid etching, sandblasting, 1,5 W, 2 W and 3 W erbium, chromium: Yttrium-scandium-gallium-garnet laser application. An untreated group was used as a control. In each group surface of the sample was analyzed with scanning electron microscopy. The remaining samples (n = 60) were built up with a self-adhesive resin cement (Rely X-U200) 3 mm in diameter and 2 mm height. After 24 h water storage at 37°C, the prepared specimens were submitted to shear bond strength test. One-way analysis of variance was used to analyze the bond strength values of different groups. Highest shear bond strength values were observed in sandblasting group however there were not statistical difference among the tested surface treatment methods. In Shear bond strength of resin, cement was independent of the surface conditioning methods applied on tested indirect resin composite.

Four chemical methods of porcelain conditioning and their influence over bond strength and surface integrity.

OBJECTIVE: To assess four different chemical surface conditioning methods for ceramic material before bracket bonding, and their impact on shear bond strength and surface integrity at debonding. METHODS: Four experimental groups (n = 13) were set up according to the ceramic conditioning method: G1 = 37% phosphoric acid etching followed by silane application; G2 = 37% liquid phosphoric acid etching, no rinsing, followed by silane application; G3 = 10% hydrofluoric acid etching alone; and G4 = 10% hydrofluoric acid etching followed by silane application. After surface conditioning, metal brackets were bonded to porcelain by means of the Transbond XP system (3M Unitek). Samples were submitted to shear bond strength tests in a universal testing machine and the surfaces were later assessed with a microscope under 8 X magnification. ANOVA/Tukey tests were performed to establish the difference between groups (α= 5%). RESULTS: The highest shear bond strength values were found in groups G3 and G4 (22.01 ± 2.15 MPa and 22.83 ± 3.32 Mpa, respectively), followed by G1 (16.42 ± 3.61 MPa) and G2 (9.29 ± 1.95 MPa). As regards surface evaluation after bracket debonding, the use of liquid phosphoric acid followed by silane application (G2) produced the least damage to porcelain. When hydrofluoric acid and silane were applied, the risk of ceramic fracture increased. CONCLUSIONS: Acceptable levels of bond strength for clinical use were reached by all methods tested; however, liquid phosphoric acid etching followed by silane application (G2) resulted in the least damage to the ceramic surface.

Enhancing osteoblast-affinity of titanium scaffolds for bone engineering by use of ultraviolet light treatment.

Ultraviolet (UV) treatment immediately prior to use is attracting attention as an effective surface conditioning method for titanium to improve osteoblast-affinity. The affinity of titanium to osteoblasts in two-dimensional plate culture has been well studied, but that in three-dimensional cultures remains unclear. Here, we examined the effect of UV treatment on titanium scaffolds, comprising micro-thin titanium fibers, used in bone engineering. Titanium scaffolds, with and without UV treatment, were seeded with rat bone marrow derived osteoblasts, and the number of cells attached to scaffolds and osteoblastic phenotype in the cultures were examined. UV treatment improved the wettability of scaffolds and significantly reduced the percentage of surface carbon. Along with these physicochemical changes in the scaffolds, cell attachment increased by a factor of 1.3 as compared to that of the untreated control. In addition, alkaline phosphatase activity and calcium deposition significantly increased by a factor of 2.3 and 2.0, respectively. Robust formation of mineralized structures consisting of clear peaks of calcium and phosphorus was observed in the UV-treated scaffolds. The observed increase in osteoblast affinity and capability of mineralized matrix formation indicates the potential use of UV-treated titanium scaffolds for bone engineering.

Evaluation of the Effect of Four Surface Conditioning Methods on the Shear Bond Strength of Metal Bracket to Porcelain Surface

This study evaluated the effect of superpulse CO2 laser irradiation and deglazing of porcelain surfaces on the shear bond strength (SBS) of metal orthodontic brackets, and compared it with two conventional etching techniques. Forty-eight Feldspathic porcelain fused to metal specimens embedded in cylindrical acrylic resin tubes were fabricated, and all the specimens were divided into four groups. In Group 1, the specimens were roughened with a diamond bur and etched with hydrofluoric acid (HFA) gel for 4 min. In Group 2, the specimens were roughened with a bur and irradiated by a CO2 laser with a 2 W power setting for 20 sec. In Group 3, the specimens were only irradiated by a CO2 laser. In Group 4, the porcelain surface was sandblasted with 50 μm aluminum oxide. Before bonding, the bracket silane was applied on the porcelain surfaces. SBS was evaluated by a Universal testing machine (Zwickroll, Germany). The remaining adhesive after the bond failure was evaluated using an adhesive remnant index (ARI). Statistical analysis was conducted by analysis of variance (ANOVA), Tukey, and Kruskal-Wallis tests. ANOVA revealed significant differences in SBS among the four groups (p<0.001). Group 1 demonstrated significantly higher bond strength (13.13±2.47) when compared with the other groups. Group 2 showed higher bond strength (9.60±1.91) when compared with group 4 (6.40±1.67) (p=0.016). Group 1 displayed the highest ARI scores among the groups. Deglazing combined with HFA etching produced the highest bond strength, but CO2 laser irradiation provided adequate bond strength and allowed for elimination of the HFA step. Deglazing is not recommended as a preliminary step before CO2 laser conditioning.

Composite–composite adhesion in dentistry: a systematic review and meta-analysis

Controversy exists in the literature regarding the most optimal repair procedure for improving the adhesion between the repair resin and the existing resin composite materials. This systematic review analyzed the adhesion potential of resin-based composites to similar and dissimilar composites. Original scientific papers on adhesion to composites published in MEDLINE (PubMed) database between 1 January 1955 and 1 June 2010 were included in this systematic review. Bond-strength data were evaluated for different factor levels, namely surface conditioning methods (control, physical, chemical, physicochemical), substrate–adherent type (being of the same kind or dissimilar), substrate aging (thermocycling or water storage), and test methods (macroshear, microshear, macrotensile, microtensile). The selection process resulted in the final sample of 41 studies. In total, 160 different surface conditioning methods, being mainly combinations of the use of etching agents, application of grinding or air-abrasion protocols, and adhesive promoters (silanes, adhesive resins), have been investigated. When substrate is aged with thermocycling, bond-strength results for composite–composite combinations of the same material were significantly influenced by the surface conditioning method (p = 0.010) and with the test method (p = 0.014), but for dissimilar composite–composite combinations, only test method (p = 0.000) showed a significant effect on the results. When substrate is aged with water storage, bond-strength results for composite–composite combinations of the same material were significantly influenced by the surface conditioning method (p = 0.000), but for dissimilar material combinations only test method showed a significant effect (p = 0.000) on the results. For the composite combinations of the same kind, the impact of surface conditioning type and the test method in thermocycled group was higher on the results.

Improvement of Silicon Solar Cell Substrates by Wet-Chemical Oxidation Studied by Surface Photovoltage Measurements

The deposition of thin and ultra-thin layers requires extremely clean, smooth and defect-free Silicon (Si) substrate surfaces as starting point. The preparation-induced surface micro-roughness and surface coverage of the substrates often affect the initial layer growth, the morphology or the adhesion of deposited layers. Si device fabrication includes multiple wet cleaning and etching steps involving different oxidizing and etching solutions, which modify the surface electronic properties according to fixed charges and defect states present on the surface. Depending on the details of the device structure, surface conditioning methods have to be carefully optimized to achieve the desired electronic interface properties.

Influence of different conditioning methods on immediate and delayed dentin sealing

Data are needed to evaluate the effect of various conditioning methods on immediate and delayed dentin sealing. The purpose of this study was to test bond strength and surface configuration of immediate and delayed dentin sealing surfaces after applying different surface conditioning methods. A total of 96 premolars were allocated to the immediate and delayed groups. The groups differed in the timing of dentin sealing. The immediate-group specimens were sealed with a self-etching adhesive immediately after preparation. The delayed-group specimens were sealed before the final ceramic restoration bonding. Provisional restorations were cemented on immediate-group and delayed-group specimens for 1 week. Four conditioning methods were used: polishing with fluoride-free pumice paste, airborne-particle abrasion with silicoated aluminum oxide, glycin, or calcium carbonate. After 24-hour storage, the shear bond strength was tested. The fractured specimens were optically inspected with a stereomicroscope. An optical 3-dimensional surface analysis was performed for quantitative and qualitative evaluation. A 2-way ANOVA with post hoc Tukey honestly significant difference tests for significant effects was performed to investigate effects of the 2 factors, sealing and conditioning, and their interaction (α=.05). Two-way ANOVA found significant differences between the sealing and conditioning groups. The immediate group had significantly lower bond strengths than the delayed group. In all groups, surface polishing produced the highest bond strengths, and airborne-particle abrasion with calcium carbonate produced the lowest. Fracture analysis found more failures in the adhesive layers in the immediate groups and a prevalence of mixed failures in the delayed groups. The surface analysis found significant abrasion and roughness when airborne-particle abrasion with silicoated aluminum oxide was used for immediate and delayed dentin sealing surfaces. Polishing and airborne-particle abrasion with silicoated aluminum oxide or glycin are efficient methods in conditioning immediate and delayed dentin sealing surfaces. Airborne-particle abrasion with silicoated aluminum oxide leaves significant surface alterations on both types of surfaces.

The effect of different surface treatments on the bond strength of PEEK composite materials

ObjectivesTo evaluate the effect of different surface treatments on the bond strength between polyetheretherketone (PEEK) composite materials and each of two different luting cements. MethodsOne hundred specimens were randomly divided into five groups (n=20/group) as follows: (A) no treatment, (B) 98% sulfuric acid, (C) 9.5% hydrofluoric acid, (D) argon plasma treatment, and (E) sandblast with 50μm Al2O3 particles. Each group was divided into two subgroups of different cements: RelyX™ Unicem and SE Bond/Clearfil AP-X™. The cements were bonded onto the specimens. All specimens were stored in distilled water at 37° for 24h. Bond strength was measured in a shear test, and failure modes were assessed by stereomicroscopy. The surfaces were observed by SEM after the different pretreatments. ResultsEtching with 98% sulfuric acid and argon plasma treatment can significantly enforce the bond strength of RelyX™ Unicem or SE Bond/Clearfil AP-X™ to PEEK composite materials in comparison to the group of no treatment, hydrofluoric acid or sandblasting (p<0.05). No adhesion was established on the groups of no treatment and hydrofluoric acid when RelyX™ Unicem was used. Applying the SE Bond/Clearfil AP-X™ system, no statistical differences were found whether hydrofluoric acid was applied or not (p>0.05). The shear bond strength value of using SE Bond/Clearfil AP-X™ was higher than that of using RelyX™ Unicem with the same surface conditioning method (p<0.05). SignificanceThe use of SE Bond/Clearfil AP-X™ after the surface of PEEK composite material treated with sulfuric acid or argon plasma can be recommended as an effective bonding method.

Comparison of Physicochemical Surface Conditioning Methods for Adhesion of bis-GMA Resin Cement to Particulate Filler Composite and Surface Characterization

This study compared the effect of physicochemical surface conditioning methods on the adhesion of bis-GMA-based resin cement to particulate filler composite (PFC) used for indirect dental restorations. PFC blocks (N block = 54, n block = 9 per group) were polymerized and randomly subjected to one of the following surface conditioning methods: a) No conditioning (Control-C), b) Hydrofluoric acid (HF)etching for 60 s (AE60), c) HF for 90 s (AE90), d) HF for 120 s (AE120), e) HF for 180 s (AE180), and f) air-abrasion with 30 µm silica-coated alumina particles (AB). The conditioned surfaces were silanized with an MPS silane, and an adhesive resin was applied. Resin composite blocks were bonded to PFC using resin cement and photo-polymerized. PFC–cement–resin composite blocks were cut under coolant water to obtain bar specimens (1 mm × 0.8 mm). Microtensile bond strength test (μTBS)was performed in a universal testing machine (1 mm/min). After debonding, failure modes were classified using stereomicroscopy. Surface characterization was performed on a set of separate specimen surfaces using Scanning Electron Microscopy (SEM), X-Ray Dispersive Spectroscopy (XDS), X-Ray Photoelectron Spectroscopy (XPS), and Fourier Transform-Raman Spectroscopy (FT-RS). Mean μTBS (MPa) of C (35.6 ± 4.9) was significantly lower than those of other groups (40.2 ± 5.6–47.4 ± 6.1) (p < 0.05). The highest μTBS was obtained in Group AB (47.4 ± 6.1). Prolonged duration of HF etching increased the results (AE180: 41.9 ± 7), but was not significantly different than that of AB (p > 0.05). Failure types were predominantly cohesive in PFC (34 out of 54) followed by cohesive failure in the cement (16 out of 54). Degree of conversion (DC) of the PFC was 63 ± 10%. SEM analysis showed increased irregularities on PFC surfaces with the increased etching time. Chemical surface analyses with XPS and FT-RS indicated 11–70% silane on the PFC surfaces that contributed to improved bond strength compared to Group C that presented 5% silane, which seemed to be a threshold. Group AB displayed 83% SiO2 and 17% silane on the surfaces.

Microshear bond strength and finite element analysis of resin composite adhesion to press-on-metal ceramic for repair actions after various conditioning methods.

This study evaluated the repair bond strength of differently surface-conditioned press-on-metal ceramic to repair composites and determined the location of the accumulated stresses by finite element analysis. Press-on-metal ceramic disks (IPS InLine PoM, Ivoclar Vivadent) (N = 45, diameter: 3 mm, height: 2 mm) were randomly divided into 3 groups (n = 15 per group) and conditioned with one of the following methods: 9.5% hydrofluoric acid (HF) (Porcelain etch), tribochemical silica coating (TS) (CoJet), and an unconditioned group acted as the control (C). Each group was divided into three subgroups depending on the repair composite resins: a) Arabesk Top (V, a microhybrid; VOCO), b) Filtek Z250 (F, a hybrid;3M ESPE); c) Tetric EvoCeram (T, a nanohybrid; Ivoclar Vivadent) (n = 5 per subgroup). Repair composites disks (diameter: 1 mm, height: 1 mm) were photopolymerized on each ceramic block. Microshear bond strength (MSB) tests were performed (1 mm/min) and the obtained data were statistically analyzed using 2-way ANOVA and Tukey's post-hoc test (α = 0.05). Failure types were analyzed under SEM. Vickers indentation hardness, Young's modulus, and finite element analysis (FEA) were performed complementary to MSB tests to determine stress accumulation areas. MSB results were significantly affected by the surface conditioning methods (p = 0.0001), whereas the repair composite types did not show a significant effect (p = 0.108). The interaction terms between the repair composite and surface conditioning method were also statistically significant (p = 0.0001). The lowest MSB values (MPa ± SD) were obtained in the control group (V = 4 ± 0.8; F = 3.9 ± 0.7; T = 4.1 ± 0.7) (p < 0.05). While the group treated with T composite resulted in significantly lower MSB values for the HF group (T= 4.1 ± 0.8) compared to those of other composites (V = 8.1 ± 2.6; F = 7.6 ± 2.2) (p < 0.05), there were no significant differences when TS was used as a conditioning method (V = 5 ± 1.7; F = 4.7 ± 1; T = 6.2 ± 0.8) (p > 0.05). The control group presented exclusively adhesive failures. Cohesive failures in composite followed by mixed failure types were more common in HF and TS conditioned groups. Elasticity modulus of the composites were 22.9, 12.09, and 10.41 GPa for F, T, and V, respectively. Vickers hardness of the composites were 223, 232, and 375 HV for V, T, and F, respectively. Von Mises stresses in the FEA analysis for the V and T composites spread over a large area due to the low elastic modulus of the composite, whereas the F composite material accumulated more stresses at the bonded interface. Press-on-metal ceramic could best be repaired using tribochemical silica coating followed by silanization, regardless of the repair composite type in combination with their corresponding adhesive resins, providing that no cohesive ceramic failure was observed.

Resin bonding to three types of polyaryletherketones (PAEKs)—Durability and influence of surface conditioning

ObjectivesThe purpose of this in vitro study was to evaluate the bond strength and durability of adhesive bonding systems to amorphous and crystalline PEKK and fiber-reinforced PEEK using five types of surface conditioning methods. MethodsOne hundred and fifty specimens of each material were conditioned mechanically and chemically, bonded with Multilink Automix to Plexiglas tubes, filled with Multicore Flow, and stored in water at 37°C for 3, 30 and 150 days. The long-term storage series were thermal cycled between 5 and 55°C for 10,000 times (30 days) or for 37,500 times (150 days) prior to tensile bond strength test (TBS). Statistical analysis was performed using Kruskal–Wallis and Wilcoxon tests with a Bonferroni–Holm correction for multiple testing (α=0.05). ResultsFiber-reinforced PEEK exhibited higher bond strengths in all five conditioning groups and at all three storage times than crystalline and amorphous PEKK, which showed lowest TBS. Highest TBS was achieved after conditioning with silica coating and priming (Rocatec Soft, Monobond Plus, Luxatemp Glaze & Bond; TBS up to 23.6MPa). SignificanceThe conditioning method has a significant influence to the bond strength of the bonding to the amorphous and crystalline PEKKs and fiber-reinforced PEEKs.

Effect of silica coating on bond strength between a gold alloy and metal bracket bonded with chemically cured resin.

ObjectiveThe purpose of this study was to evaluate the effects of three different surface conditioning methods on the shear bond strength (SBS) of metal brackets bonded directly to gold alloy with chemically cured resin.MethodsTwo hundred ten type III gold alloy specimens were randomly divided into six groups according to the combination of three different surface conditioning methods (aluminum oxide sandblasting only, application of a metal primer after aluminum oxide sandblasting, silica coating and silanation) and thermocycling (with thermocycling, without thermocycling). After performing surface conditioning of specimens in accordance with each experimental condition, metal brackets were bonded to all specimens using a chemically cured resin. The SBS was measured at the moment of bracket debonding, and the resin remnants on the specimen surface were evaluated using the adhesive remnant index.ResultsApplication of metal primer after aluminum oxide sandblasting yielded a higher bond strength than that with aluminum oxide sandblasting alone (p < 0.001), and silica coating and silanation yielded a higher bond strength than that with metal primer after aluminum oxide sandblasting (p < 0.001). There was no significant change in SBS after thermocycling in all groups.ConclusionsWith silica coating and silanation, clinically satisfactory bond strength can be attained when metal brackets are directly bonded to gold alloys using a chemically cured resin.

Bonding effectiveness of two adhesive luting cements to glass fiber posts: pull-out evaluation of three different post surface conditioning methods.

The purpose of this study was to evaluate the bond strength at the post/resin-cement interface with 3 different surface treatments of glass fiber posts and with 2 different luting resin cements. Sixty glass fiber posts (RelyX Fiber Post) were randomly divided into 3 groups (n = 20) and were luted with a dual-polymerizing self-adhesive universal resin cement (RelyX Unicem) and with a dual-polymerizing resin cement (RelyX ARC). This was carried out in association with a dual-polymerizing adhesive (Scotchbond Multi-Purpose Plus) in simulated plexiglass root canals after receiving three different pretreatment procedures. A pull-out test was performed on each sample to measure bond strengths. Data were analyzed with two-way ANOVA. Two samples from each group were processed for SEM observations in order to investigate the morphologic aspect of the post/cement interface. Both resin cements demonstrated significant different bond strength values (P < 0.0001). The surface treatment result was also statistically significant (P = 0.0465). SEM examination showed a modification of the post surface after pretreatment with methyl methacrylate. The dual-polymerizing self-adhesive universal resin cement achieved higher MPa bond strength values. The use of methyl methacrylate as a surface treatment of glass fiber posts provided a significant increase in bond strengths between the posts and both luting materials.

Evaluation of shear bond strength of repair acrylic resin to Co-Cr alloy.

PURPOSEThe purpose of this study was to investigate the impact of different surface treatment methods and thermal ageing on the bond strength of autopolymerizing acrylic resin to Co-Cr.MATERIALS AND METHODSCo-Cr alloy specimens were divided into five groups according to the surface conditioning methods. C: No treatment; SP: flamed with the Silano-Pen device; K: airborne particle abrasion with Al2O3; Co: airborne particle abrasion with silica-coated Al2O3; KSP: flamed with the Silano-Pen device after the group K experimental protocol. Then, autopolymerized acrylic resin was applied to the treated specimen surfaces. All the groups were divided into two subgroups with the thermal cycle and water storage to determine the durability of the bond. The bond strength test was applied in an universal test machine and treated Co-Cr alloys were analyzed by scanning electron microscope (SEM). Two-way analysis of variance (ANOVA) was used to determine the significant differences among surface treatments and thermocycling. Their interactons were followed by a multiple comparison' test performed uing a post hoc Tukey HSD test (α=.05).RESULTSSurface treatments significantly increased repair strengths of repair resin to Co-Cr alloy. The repair strengths of Group K, and Co significantly decreased after 6,000 cycles (P<.001).CONCLUSIONThermocycling lead to a significant decrease in shear bond strength for air abrasion with silica-coated aluminum oxide particles. On the contrary, flaming with Silano-Pen did not cause a significant reduction in adhesion after thermocycling.

Effects of Different Surface Treatments on Bond Strength Between Resin Cements and Zirconia Ceramics

This study compares the bond strength of resin cement and yttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic with different surface conditioning methods. Two hundred presintered Y-TZP ceramic specimens were prepared, sintered (4 × 4 × 4 mm), and randomly assigned to four equal groups as control (C, no conditioning); airborne particle abraded (APA, air abrasion with 11 μm Al2O3); tribochemical silica coating/silane coupling system (TSC, Rocatec, air abrasion with 110 μm Al2O3, 30 μm silica-coated Al2O3 and silane); and laser (L, Er:YAG laser irradiation treated at a power setting of 200 mJ). After specimen preparation, composite resin cylinders were prepared and cemented with resin cements (Clearfil Esthetic, Panavia F 2.0, Rely X-U100, Super Bond C&B, and Multilink Automix) on the ceramic surfaces and kept in an incubator at 37°C for 60 days. All specimens were tested for shear bond strength with a universal testing machine, and fractured surfaces were evaluated by environmental scanning electron microscopy. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U-tests (α=0.05). The bond strengths for C and L groups were not significantly different according to adhesive resin cement. APA and TSC resulted in increased bond strength for Panavia F 2.0 and Rely X-U100 resin cements. Additionally, TSC presented higher bond strength with Multilink Automix. Adhesive fracture between the ceramic and resin cement was the most common failure. Complete cohesive fracture at the ceramic or composite cylinders was not observed. Regardless of the adhesive resin cement used, laser treatment did not improve resin bond strength.

Influence of Various Surface Conditioning Methods on Bonding Orthodontic Brackets to Porcelain Surface

Objective: To investigate the effects of different surface conditioning methods on shear bond strength (SBS) of metal brackets bonded to porcelain surfaces and the influence of silane coupling agent in altering the bond strength. Materials and methods: A total of 80 feldspathic porcelain specimens were used. They were divided into eight different groups based on different surface conditioning methods and combinations: Sandblasting (SAB), hydrofluoric acid (HFA), diamond bur (DB) and air abrasion (AA). Silane coupling agent was used in five groups. Metal brackets were bonded and subjected to SBS testing. The efficiencies between the five individual methods used were analyzed. ARI scoring was done after debonding. Results: The SBS range was between 3.19 and 14.38 (MPa) with a mean of 8.89 ± 3.25 (MPa). The difference between mean SBS between different groups was significant (p 0.001). When compared to AA group (9.03 ± 0.59 MPa) the non-AA group were lower (8.87 ± 3.46 MPa) but again the difference was not significant (p > 0.001). ARI score 0 was observed in 47 instances (58.8%), score 1 was observed in 25 instances (31.2%). Conclusion: The results indicated that surface conditioning alone without silanation produced significantly low SBS. Air abrasion followed by silanation produced favorable bond strength and might have the potential to replace alternative methods.

Adhesion of veneering resins to polymethylmethacrylate-based CAD/CAM polymers after various surface conditioning methods

Objectives. The aims of this study were to test whether the bond strength of a hybrid composite and a PMMA-based veneer to CAD/CAM polymers would improve after pre-treatment and to evaluate the failure types after debonding. Materials and methods. Three types of PMMA-based (CAD-Temp, artBloc Temp and TelioCAD) CAD/CAM blocks were obtained (N = 360, n = 15 per test group). They were divided into four groups to be conditioned with the following methods: (a) no-treatment, (b) air-abrasion (50 μm Al2O3), (c) air-abrasion (50 μm Al2O3) + MPS-Silane (Monobond S) + Adhesive resin (StickResin) (for Gradia)/MMA (for Integral Esthetic Press) application, (d) Silica coating and silanization (CoJet-System). The conditioned surfaces were veneered with a hybrid composite (Gradia) or a PMMA-based resin (Integral esthetic press). After water storage (1 week, 37°C), the bond strength was measured. Data were analyzed using 3-way ANOVA and post-hoc Scheffé test (α = 0.05). Results. Surface-conditioning method, veneer type and CAD/CAM polymers significantly affected the results. Hybrid composite did not bond to non-conditioned CAD/CAM polymers. Regardless of the conditioning method, PMMA-based resin showed significantly higher bond strength to all CAD/CAM polymers compared to hybrid composite. Air-abrasion increased the bond strength in all tested groups. Additional silane application after air-abrasion did not significantly increase the bond strength of hybrid composite. While exclusively adhesive failures were observed between the hybrid composite and the CAD/CAM polymers, PMMA veneer demonstrated cohesive failures in the CAD/CAM polymers. Conclusion. CAD/CAM polymers could be veneered with only a PMMA-based veneer with and without air-abrasion.

Evaluation of shear bond strength of three different types of artificial teeth to heat cure denture base resin: An in vitro study

Bonding of artificial teeth and denture base material remained a significant problem for successful prosthetic treatment. The purpose of this in vitro study was to evaluate shear bond strength of three different artificial teeth with heat cure denture base material after various surface conditioning methods and thermocycling. Ninety mandibular first molar denture teeth were selected. They were divided into three groups, Group I: Nanocomposite resin (Veracia), Group II: Composite teeth (Endura), and Group III: Cross-linked acrylic denture teeth (Acry rock). All groups were further subdivided into subgroups based on surface conditioning methods. Subgroup A: No surface conditioning (control group), Subgroup B: Surface conditioning with methyl methacrylate-based bonding agent (Vitacoll), and Subgroup C: Air abrasion with 50 μm aluminum oxide powder particles plus silane-coupling agent (Monobond-S) and Vitacoll bonding agent. Evaluation of shear bond strength of all the specimens was done using universal testing machine. Mean shear bond strength of Group I, Subgroup B (6.87 ± 0.934) showed higher value when compared with Group II, Subgroup B (6.76 ± 1.84) and Group III, Subgroup B (5.66 ± 2.18). The control group (untreated surface) of all three types of artificial teeth used in this study showed significantly lower shear bond strength values than experimental groups (surface conditioning methods; P < 0.05). The results of this study suggest that there were significant differences in shear bond strength among control group and surface treatment groups of denture teeth bonded to heat cure denture base resin.

Silica-based Nano-coating on Zirconia Surfaces Using Reactive Magnetron Sputtering: Effect on Chemical Adhesion of Resin Cements

To compare the effect of silica (Si)-based nano-coating deposited by reactive magnetron sputtering (RMP) with that of conventional surface conditioning using metal/zirconia primer alone or after air-particle abrasion on the adhesion of resin cements to zirconia ceramic. Two hundred forty zirconia ceramic blocks (Cercon) were sintered, finished with 1200- grit SiC paper under water cooling, and cleaned ultrasonically in distilled water for 10 min. The blocks (4.5 mm x 3.5 mm x 4.5 mm) were randomly divided into 24 groups (n = 10) according to 3 testing parameters: a) resin cements (Multilink, Panavia F, RelyX U100), b) surface conditioning (no conditioning as control group; Metal/Zirconia Primer; air abrasion + Metal/Zirconia Primer; Si-based nanofilm + Monobond s); c) aging (no aging vs thermocycling at 5°C to 55°C, 6000 cycles). The nanofilm was deposited by direct current using argon/oxygen plasma (8:1 in flux) on the zirconia surface. Resin cements were bonded to zirconia surfaces using polyethylene molds. The shear bond strength (SBS) test was performed using a universal testing machine (1 mm/min), and after debonding, the substrate and adherent surfaces were analyzed using optical and scanning electron microscopes to categorize the failure types. The data were statistically evaluated using 3-way ANOVA and Tukey's test (5%). Resin cement type (p < 0.05), surface conditioning method (p < 0.05), and aging condition (p < 0.05) had a significant effect on the bond strength results. Interactions were also significant (p < 0.05). In the nonaged condition, while control groups presented the lowest results with all cements (0 to 5.2 MPa), the airabraded group in combination with RelyX U100 resulted in the highest SBS (21.8 ± 6.7 MPa). After aging, the SBS results decreased in the air-abraded groups for all cements (4.54 to 9.44 MPa) and showed no statistical significance compared to the Si-based nanocoated groups (4.24 to 6.44 MPa). After air-abrasion and primer application, only Panavia F and RelyX U100 cements showed exclusively mixed failures, but after nanofilm coating and silanization, all cements showed exclusively mixed failures with and without aging. Chemical adhesion of the resin cements tested to zirconia was similar after silica-based nanofilm deposition and air abrasion followed by primer application.