Influence of different surface treatments on zirconia/resin shear bond strength using one-bottle universal adhesive

ABSTRACT

This study was designed to evaluate the effect of different treatments on the zirconia/resin shear bond strength (SBS) using commercial one-bottle universal adhesive. Zirconia discs with different surface treatments (blank control; airborne-particle-abrasion; glazing) were bonded to the bovine enamel surfaces using one-bottle universal adhesive. All specimens were tested for SBS (MPa) before and after 10000 thermocycles. Statistically analysis were conducted by using one-way analysis of variance and multiple-comparison least significant difference tests (α = 0.05). Airborne-particle-abrasion group showed higher SBS (36.19 ± 11.86) than control group (14.98 ± 5.90) and glazing group (10.63 ± 5.39) (p < 0.05). After thermocycling test, the SBS significantly decreased for control group (8.84 ± 2.55) and glazing group (6.18 ± 2.78) while not for airborne-particle-abrasion group (41.5 ± 7.95). One-bottle universal adhesives combined with airborne-particle-abrasion showed quite high SBS of zirconia/resin, which was appropriate for bonding of zirconia restoration.     

Effect of thermal cycling and low pressure sandblasting on the bond strength of a self-adhesive cement to Y-TZP zirconia

The aim of this investigation was to assess the influence of several surface treatments on the shear bond strength (SBS) of a self-adhesive resin cement containing 10-methacryloxydecyl-dihydrogenphosphate monomer to densely sintered zirconia ceramic, before and after thermal cycles. Hundred densely sintered zirconia cylinders were divided into five groups (n = 20). Each of them received a different surface treatment: (1) control [No_T], with the zirconia surface unconditioned, (2) low pressure air abrasion [Sand_S], (50 μm, 1 bar), (3) standardized air abrasion [Sand_H], (50 μm, 2.8 bar), (4) standardized Rocatec? Plus (silica-coated alumina oxide) air abrasion (2.8 bar) and silanization [Roc_H], (5) low pressure Rocatec? Plus (silica-coated alumina oxide) air abrasion (1 bar) and silanization [Roc_S]. Five more surface-treated specimens were addressed to scanning electron microscope for qualitative observations. After specimen fabrication, subgroups of 10 bonded samples were stored in water either for 24 h (T1) or subjected to 5000 thermal cycles (T2); SBSs were determined with a universal testing machine at a crosshead speed of 1 mm/min. At T1, mean SBSs (MPa) obtained for the examined groups were: [Sand_H] 16.24 ± 2.95; [Sand_S] 16.01 ± 2.68; [Roc_H] 17.17 ± 1.64; [Roc_S] 15.92 ± 1.99. All surface treatments positively affected (p < 0.05) the initial self-adhesive cement adhesion to zirconia with respect to No_T (13.29 MPa). Artificial aging decreased the bond strength in all test groups significantly, but no spontaneous debonding was observed in [No_T]: at T2, SBS values ranged from 7.76 ± 2.37 (No_T) to 8.89 ± 1.74 (Sand_S), with no statistically significant difference between groups (p = 0.5293). Both air abrasion with alumina oxide and Rocatec? universal bonding system, used with hard or low air pressure, produced comparable effects on cement–zirconia interface before and after thermal cycles. After artificial aging, minimal differences in bond strength values between sandblasted and control groups were not of statistical significance.     

Bond strength of veneering porcelain to zirconia after different surface treatments

Aim: The aim of this study was to evaluate the effect of various surface treatments on the bond strength of veneering feldspathic porcelain to zirconia. Methods: Fifty yttria-stabilized tetragonal zirconia polycrystalline specimens were divided into five groups (n = 10) according to various surface treatments. The groups were as follows: Group 1: control group with liner application and no further surface treatment; Group 2: air-particle abrasion with 110 μm of alumina (Al₂O₃) particles; Group 3: grinding with a diamond disk; Group 4: Nd:YAG laser irradiation (the laser and the energy parameters were 10 Hz, and 2 W and 200 mJ, and the pulse duration (short pulse) range was up to 180 μs); Group 5: selective infiltration etching (SIE). After surface treatments, a liner application was performed for all surfaces according to the manufacturer’s instructions. Veneering porcelain was applied on zirconia surfaces using a Teflon mold. Shear bond strength was tested using a universal testing machine. The fractured surface morphologies were examined with scanning electron microscopy. The data were statistically analyzed using Mann–Whitney U and Kruskal–Wallis tests (α = .05). Results: The Megapascal values of the bonding groups were as follows: G1 = 8.62 ± 1.12, G2 = 13.87 ± 5.08, G3 = 12.31 ± 3.35, G4 = 17.32 ± 6.16, and G5 = 16.17 ± 4.55. Statistically significant differences were observed between the control group and the other groups (p < 0.05). Group 4 had the highest bond strength while G1 showed the lowest bond strength. No significant differences were found between the Nd:YAG, grinding, sandblasting, and SIE groups. Conclusion: Surface treatments had different effects on the shear bond strength of feldspathic porcelain to zirconia. Surface treatment techniques used in this study can be used on zirconia specimens prior to liner application to obtain an acceptable bond strength of veneering porcelain to zirconia. The effect of Nd:YAG laser irradiation and SIE techniques on bond strength of veneering ceramic to zirconia should be evaluated with further studies.     

Effect of different surface treatments on the shear bond strength of resin cement to zirconia ceramic and metal alloy*

The bonding of resin cement to ceramic materials plays an important role in dentistry. The purpose of this study is to evaluate the effects of various surface treatments on the shear bond strength (SBS) of zirconia ceramic and metal alloy. A total of 60 specimens were prepared from Y-TZP ceramic and metal alloy. The specimens were divided into three subgroups (n = 10) that received different surface treatments for each material. An Er:YAG laser (ER), a femtosecond laser (FS), and air-borne particle abrasion (A) were employed as surface treatments. One specimen from each group was analyzed using a scanning electron microscope (SEM) at 500 x magnification after surface treatments. The self-adhesive resin cement was then bonded to the treated surfaces using a Teflon mold. The specimens were thermocycled for 5,000 cycles at 5–55 °C, and then the SBS test was performed. Kruskal–Wallis and Mann–Whitney U tests were used to determine the differences between the groups (p = 0.05), and failure modes were evaluated for each specimen. Statistical analyses revealed significant differences between the surface treatment methods. The mean SBS values of the air-borne particle-abraded groups were higher than those of the other groups. The femtosecond-irradiated groups of each material showed significantly higher SBS values than the Er:YAG-irradiated groups (p < 0.05). Within the limitations of this study, air-borne particle abrasion and the femtosecond laser were more effective than Er:YAG laser treatment.     

Effects of different surface treatments on shear bond strength between ceramic systems and metal brackets

The aim of this study was to evaluate the shear bond strength of orthodontic brackets bonded to different kinds of ceramic surfaces after different surface conditioning methods. A total of 120 ceramic disks were divided into two main groups in terms of feldspathic or lithium disilicate. Each ceramic group was further subdivided into six subgroups depending on surface treatment (n = 10). The ceramic surfaces were conditioned by one of the following methods: Group C: control group; Group P: %37.5 orthophosphoric acid; Group HF: %9.6 hydrofluoric acid; Group L: Nd-YAG laser irradiation; Group SB: sandblasting with 50 µm Al₂O₃ particles; and Group DB: grinding with a diamond bur. Surface roughness value was evaluated with a digital profilometer. Surface topographies of one specimen from each group were observed by atomic force microscopy (AFM) after surface treatments. All samples were primed with silane before the bracket bonding, including the control group. Metal brackets were bonded to the specimens with a light curing composite resin. The samples were stored in distilled water for 24?h and thermocycled 2500× at 5 and 55 ºC for 30?s. Shear bond strengths between the ceramic surface and the bracket were measured with a universal testing machine at a crosshead speed of 0.5 mm/min. Failure modes were classified as adhesive, cohesive, or mixed. Data were analyzed using ANOVA and Tukey's tests (α = .05). Group SB had significantly rougher surface compared with the other groups in each ceramic system (p < .05), and Group SB demonstrated significantly higher shear bond strengths than other groups as well. Within the limitations of this study, surface conditioning methods, except for sandblasting and grinding, were associated with lower shear bond strengths; however, thermocycling may have had negative effects on bond strengths of specimens. Furthermore, in each ceramic system, there was a significant difference between surface-conditioning methods and surface roughness with regard to shear bond strength.     

Influence of surface energy parameters of dental self-adhesive resin cements on bond strength to dentin

The purpose of this study was to determine the surface energy parameters of dental self-adhesive resin cements (SRCs) and to measure their bond strength to dentin. Six dental SRCs (RelyX Unicem Clicker, RU; Maxcem Elite, ME; BisCem, BC; Clearfil SA Luting, SA; Multilink Speed, MS; seT PP, SP) and one resin-modified glass ionomer cement (RelyX Luting 2, RL; control) were tested. Smear layer-covered bovine dentin was used as bonding substrate. Using the dynamic sessile drop method, surface energy, surface energy components, degree of hydrophobicity/hydrophilicity (expressed as ΔG _sws using thermodynamic notation), and apparent surface energies for each material were calculated. The luting cements were bonded to the dentin and stored in water at 37?°C for 24?h prior to shear bond strength test (n?=?10). Pearson correlation analysis was applied to detect possible correlations between surface energy parameters and measured shear bond strength (α?=?0.05). RU, SA, and MS produced negative ΔG _sws values (hydrophobic), whereas ME, BC, SP, and RL yielded positive ones (hydrophilic). RU had the highest value among all six SRCs tested, the value for MS being statistically equivalent (p?=?0.785). The base component, ΔG _sws, and surface energy determined with water showed significant negative linear correlations with dentin bond strength (r/p?=??0.801/0.030, ?0.900/0.006, and ?0.892/0.007, respectively). These results suggest that bonding to smear layer-covered bovine dentin was governed by the base component and the hydrophobicity/hydrophilicity of the SRCs.     

Effects of surface treatments on the shear bond strength of luting cements to zirconia

Objective: The aim of this in vitro study was to evaluate the effect of surface treatments on the shear bond strength of resin cements to zirconia. Material and methods: Sintered zirconia specimens (n = 192) were divided into four different surface treatment groups: control (no treatment); airborne-particle abrasion; glaze layer and hydrofluoric acid (HF) application, and hot etching solution application. Then, each group was divided into four subgroups (n = 12), and three different resin cements were applied to the zirconia surfaces. The shear bond strength value of each specimen was measured after 5000 thermo cycles. The failure types were examined with a stereomicroscope and the effects of the surface treatments were evaluated with a scanning electron microscope. Results were analyzed using analysis of variance and Tukey’s post hoc tests (α = 0.05). Results: The surface treatment and resin cement type significantly affected the bond strength results (p < 0.05). For all resin cements, the airborne-particle abrasion treatment increased the shear bond strength values (p < 0.05). The glaze layer & HF application increased shear bond strength values for all groups, except the Single Bond Universal-RelyX Unicem Aplicap group (p < 0.05). The surface roughness values of airborne-particle abraded specimens were similar to comparable values for specimens from the control group and the hot etching solution group (p > 0.05). The glaze layer & HF application group produced the highest surface roughness values (p < 0.05). Conclusion: The results of this study recommend using the appropriate combination of surface treatment and adhesive/silane coupling agent to achieve durable zirconia-resin bonding.     

Effect of different surface treatments on bond strength of recycled brackets to feldspathic porcelain

Aim: The aim of the study was to compare the shear bond strength of three different types of recycled brackets on porcelain facets following different surface treatments. Materials and Methods: Eighty-four porcelain facets were produced by duplication of the labial surface of a maxillary right first premolar. Each porcelain facet was individually embedded in autopolymerizing acrylic resin. A thin coat of sealant was also painted on the bracket base and cured for 15 s before applying the paste. The bracket was then positioned on the porcelain facet, pressed lightly and light-cured. Each specimen was loaded into a universal testing machine using Nexjen software for testing, with the long axis of the specimen perpendicular to the direction of the applied force. Then, the brackets were rebonded following different surface treatments (Laser, hydrofluoric acid, sandblasting with Al₂O₃, and silane treatment). Kruskal–Wallis analysis of variance and post hoc Wilcoxon signed-rank tests were performed to test the differences in shear bond strength values (p < 0.05). The significance of differences in the ARI scores was analyzed with chi-square test (p < 0.05). Results: Statistical analysis indicated significant differences among surface treatment procedures (p < 0.0001). In addition, the effect of the first and second bonding factors on shear bond strength behaviors was shown to be significant for the brackets (p < 0.001). Conclusion: The use of sandblasting, HF treatment and silanization procedure could be used for improving the rebond shear bond strength of zirconia brackets to porcelain surface. However, rebonding the brackets to porcelain surfaces may not be recommended due to the dramatic decrease in bonding values.     

Effectiveness of different surface cleaning methods on the shear bond strength of resin cement to contaminated zirconia: an in vitro study

The purpose of this in vitro study was to evaluate and compare the effectiveness of different surface cleaning methods on the shear bond strength (SBS) of zirconia ceramic surfaces. Seventy polished and cleaned zirconia disk specimens of 8 mm in diameter and 3.4 mm in thickness were immersed in fresh saliva. They were then pressed into a freshly mixed silicone disclosing medium. Six different cleaning methods were applied to the tested groups; they were airborne-particle abraded (AA), covered with a cleaning paste (Ivoclean®) (IV), etched with orthophosphoric acid (PA), immersed in alcohol (AL), rinsed with tap water only (WA), or cleaned with steam (SC). No surface cleaning was done after saliva immersion and silicone disclosing medium contamination to the control group (CC). The specimens were then bonded to an adhesive resin cement using polyethylene tubes. SBS was determined using a universal testing machine at a crosshead speed of 1 mm/min. The specimens were also examined with a scanning electron microscope and a stereomicroscope. Group AA yielded the highest SBS value (7.01 ± 1.4 MPa) among the groups, while Group WA had the lowest SBS value (3.03 ± 0.8 MPa). The SBS values of Group AA (7.01 ± 1.4 MPa) and IV (6.2 ± 1.7 MPa) were also significantly higher than those of the remaining four groups (p < 0.05). Within the limitations of this in vitro study, it was concluded that among the various cleaning methods tested, airborne-particle abrasion and Ivoclean® paste were effective in cleaning the zirconia surface.     

Effect of different surface shapes formed by femtosecond laser on zirconia-resin cement shear bond strength

Objective: The purpose of this study was to evaluate the effect of different surface shapes formed by femtosecond (FS) laser on zirconia (Y-TZP)-resin cement shear bond strength (SBS). Background data: All ceramic restoration is used as an alternative to metal-ceramic restorations, due to its better aesthetics, strength, and toughness properties. However, bond strength of restoration to tooth and other materials is effective to long term success of the restoration, and to achieve it surface treatment is required on ceramic surface. Materials and methods: Forty square-shaped zirconia samples were prepared and assigned to four groups of 10. The details of the groups are as follows: Group A, square-shaped recessed surface; Group B, square-shaped projection surface; Group C, circular-shaped recessed surface; Group D, circular-shaped projection surface. The SBSs values were performed with a universal testing machine at a crosshead speed of 1 mm/min. The data were analyzed statistically using analysis of variance (ANOVA) and Tukey HSD multiple comparisons tests. Results: The one-way ANOVA results on SBSs of the zirconia material bonded with resin cement revealed significant differences among the groups (p < 0.05). The Tukey HSD test results revealed that Group B and D had significantly higher SBS values than other groups (p < 0.05), but there were no significant differences between each other (p > 0.05). Additionally, Group A and C had significantly lower values than other groups (p < 0.05). Conclusions: Different surface shapes formed by FS laser provided a significant increase in SBSs. The SBS values of projection surfaces of circular and square-shapes are greater than that of recessed surfaces of circular and square-shapes.     

Effect of femtosecond laser beam angle and formed shape on surface roughness and shear bond strength between zirconia and resin cement

Achieving adhesion between resin cement and zirconia requires pretreatment of the surface. This in vitro study aimed to evaluate the effect of femtosecond laser beam angle and the shape of the formed surfaces, on the roughness and shear bond strength (SBS) of resin cement to zirconia ceramic. Seventy Y-TZP ceramic specimens were divided into seven groups (n = 10). A femtosecond laser irradiation was performed on the ceramic surface of three shapes (spiral (SP), square (SQ) and circular (CI) and at two angles (30 and 90°) to give SP-30, SQ-30 and CI-30 and SP-90, SQ-90 and CI-90, respectively. After treatment, the surface roughness of all specimens was evaluated using a profilometer. One specimen from each group was analysed using a scanning electron microscope. The bonded specimens were thermocycled 5000 times and then an SBS test was performed. Kruskal-Wallis and Mann-Whitney U tests were used to analyse surface roughness and SBS values. The control group had statistically lower surface roughness (R_a) values than the treated groups (p < 0.05). SP-30 and SQ-30 laser treated specimens showed higher R_a values than the other specimens. Statistically significant SBS values (p = 0.000) were observed between the groups. All laser treated samples showed greater SBS compared to the control group. SP-30, SQ-30 and SQ-90 groups showed the highest SBS values. Within the limitations of this experimental study, the highest mean values for R_a and SBS were achieved with SP and SQ surfaces using a 30° angle laser beam.     

Effect of hot-etching treatment on shear bond strength of zirconia to resin cement

ABSTRACT

The purpose of this study was to evaluate the effect of hot-etching surface treatment on the shear bond strength between zirconia ceramics and resin cement. Ceramic cylinders were divided randomly into 10 groups (n?=?10) according to different surface treatments (blank control; airborne particle abrasion; hot-etching for 10?min; hot-etching for 30?min; hot-etching for 60?min) and whether or not performed thermal cycling fatigue test. Flat enamel surfaces, were prepared from human permanent incisors and were bonded to the zirconia discs. All specimens were subjected to shear bond strength test by a universal testing machine. All data were statistically analysed using one-way analysis of variance and multiple comparison least significant difference tests (α?=?0.05). Hot-etching for 60?min treatment produced higher bond strengths than the other treatment. Surface treatment of zirconia with a hot-etching solution might enhance surface roughness and bond strength between zirconia and resin cement.     

Effect of dentinal surface preparation on the bonding of self-adhesive luting cements

The purpose of the present study was to evaluate the bond strength and the interaction morphology of self-adhesive resin luting cements (SLCs) to dentin prepared with different methods. Four SLCs were used: RelyX U100^®, RelyX U200^®, Clearfil SA Luting^®, and SmartCem2^®. A flat dentin surface of 40 human molars was exposed and each tooth was sectioned in four tooth-quarters, which were distributed into four groups according to the SLC used to cement indirect resin composite restorations. The tooth-quarters of each group were then distributed in four subgroups according to the method used for dentin preparation: flat-ended cylindrical fine-grit diamond, flat-ended cylindrical median-grit diamond, flat-ended cylindrical plain-cut tungsten carbide, or abraded with #600-grit SiC paper (control). The restored tooth-quarters were sectioned to obtain beams (0.8?mm²) and submitted to the microtensile bond strength test (n?=?10). The results were analyzed using two-way ANOVA/Tukey (α?=?0.05). Forty-four additional teeth were used for micromorphological investigation of the SLC/dentin interface and of the topographic aspect of the dentin surfaces after application of the SLCs. Only the bond strength of RelyX U200 was significantly influenced by the surface preparation. No interference was identified on the micromorphological aspect of the bonding interfaces. The topographic investigation of the dentinal surfaces showed that the SLCs were not able to effectively remove the smear layer and etch the underlying dentin, irrespective of the preparation method. So, the interference of the dentin preparation on the bond strength of SLCs is material dependent, but don’t influence the micromorphologic aspect of the interaction zone.     

The effect of MDP-based primer on shear bond strength of various cements to two different ceramic materials

The aim of this study was to determine the effect of 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-based primer on the shear bond strengths of thermally aged self-adhesive and conventional adhesive resin cements and zinc phosphate cement to zirconia and lithium disilicate substructures. Sixty zirconia (Z) and 60 lithium disilicate (L) disk specimens were cut from ceramic blocks. Each group was divided into six subgroups (n = 10). Half of the specimens of each ceramic group were treated with primer (P) and the other half was remained untreated. Three types of cement were applied: zinc phosphate cement [(ZPC) (Hoffmann Harmonic Shades)]; self-adhesive resin cement [(SAC) (RelyX U200)]; conventional adhesive resin cement [(CAC) (C&B)]. The specimens were subjected to thermal aging procedure for 1 week under 37 °C water bath. Shear bond strength (SBS) was determined using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed with three-way (ANOVA). Pairwise comparisons and interactions between groups were analyzed by using Tukey’s simultaneous confidence intervals. There was no significant difference between the SBS values of SAC-Z (11,47 ± 0,47) and SAC-ZP (11,39 ± 0,42) (p > 0.05). However, the SBS values of SAC-L (12.34 ± 0,55) and SAC-LP (12,50 ± 0,49) were significantly higher than those of SAC-Z and SAC-ZP (p < 0.00). The use of primer significantly increased the SBS value of CAC-ZP (8,05 ± 0,55) when compared to the SBS value of CAC-Z (3,53 ± 0,41) (p < 0.00). Resin cement that contains methacrylate monomers with phosphoric ester functional groups exhibited reliable bond to zirconia. However, the use of an MDP-based primer may not further improve its bond strength.     

Effect of ceramic surface treatments on the bond strength of different composite resins

This study was aimed to observe the relationship between the different surface treatments and the bond strength of both composite based adhesive cement and zirconia ceramic. Thirty-two zirconia ceramic discs were fabricated by following the instructions of manufacturer (5 × 5 × 1.5 mm). Four subgroups were obtained from the specimens according to the specified surface treatments respectively: (a) C: control groups: no treatment; (b) SB: sandblasting with 125 μm aluminum oxide particles for 10 s; (c) SC: silica coating for 10 s; (d) Nd :YAG laser . The composite resin specimens Panavia F and Clearfil SA were introduced and polymerized to the treated bonding areas. Afterwards the specimens were stored in distilled water at 37 °C during 24 h, and the shear test was applied. The data were statistically analyzed by ANOVA and Duncan tests. The bond strength was stated significantly higher in silica coating/Panavia F group (23.35 MPa). The lowest bond strength was stated in control groups cemented with Clearfil SA (12.25 MPa). As a result it was determined that the bond strength has affected the both surface treatments and cement types (p < 0.001). The silica coating –treated zirconia ceramic recorded a significant increase in mean bond strength values.     

The effect of different surface pretreatments on the bond strength of veneering resin to polyetheretherketone

The aim of this study was to investigate the effect of different surface pretreatment methods on the bond strength of veneering resin to polyetheretherketone (PEEK) based aesthetic frameworks. Five hundred and forty PEEK disks were fabricated and divided into 6 pretreatment groups (n = 90); (C) untreated control group, (B) airborne-particle abrasion, (S) silica coating, (L) etching with Er:YAG (erbium-doped yttrium aluminium garnet) laser, (LB) etching with Er:YAG laser and airborne-particle abrasion and (LS) etching with Er:YAG laser and silica coating. After topographical surface examinations, specimens were conditioned with adhesive and veneering resin was polymerized onto the PEEK specimens. Twenty-four hours after veneering, specimens were subjected to thermal aging. Afterwards, shear bond strength (SBS) tests were performed and the obtained data were analyzed with one-way ANOVA and Tukey test at a significance level of α = .05. Group B (1.58 ± 0.15 μm), Group L (1.79 ± 0.29 μm), Group LB (2.20 ± 0.23 μm) and Group LS (2.31 ± 0.52 μm) demonstrated significantly higher surface roughness (SR) values compared to Group C (1.03 ± 0.11 μm). Group B (10.97 ± 2.88 MPa), Group S (12.07 ± 2.82 MPa), Group LB (12.09 ± 2.08 MPa) and Group LS (13.14 ± 1.45 MPa) demonstrated significantly higher SBS values compared to Group C (6.35 ± 1.21 MPa). Airborne-particle abrasion, silica coating or their combined use with Er:YAG laser system establish durable bond between PEEK and resin; however, only Er:YAG laser treatment has no positive effect on resin-PEEK bond.     

Evaluation of different desensitizing agents effect on shear bond strength of adhesive resin cement to dentin

Desensitizing agents can inhibit the bonding strength between dentin and adhesive resin cement. This study evaluated the effects of different desensitizing agents on the shear bond strength of adhesive resin cement to dentin. Sixty freshly extracted and caries free teeth were classified into five experimental groups, randomly (n?=?12). Each group was treated with a different desensitizing agent (Teethmate, Shield Force Plus, Admira Protect and Ultra-Ez) respectively, except for an untreated control group. After desensitizing agents and adhesive resin cement were applied to each dentin surface, all specimens were stored in incubator at 37?°C for 24?h. The shear bond strength was tested with a Universal testing machine at a 0.5?mm/min crosshead speed. Data were analysed by using a statistical software (SPSS 22). The results of the measurements were analysed by Kruskal Wallis test with Bonferroni correction and multiple comparisons were made by Wilcoxon test (p???.01). Specimens were examined by a scanning electron microscope, additionally. The Shield Force Plus showed significantly the highest shear bond strength compared with other groups (p?<?.01). Ultra-Ez showed the lowest shear bond strength (p?>?.01). There was no significant difference among Teethmate and Admira Protect groups (p?>?.01). Desensitizing agents containing resin monomers increased the bonding strength, however desensitizers containing calcium phosphate, potassium nitrate and fluoride did not effect the bonding strength of resin cement to dentin.     

Microtensile bond strength of composite-to-composite repair with different surface treatments and adhesive systems

Objectives: The purpose was to investigate the effect of different surface treatments and bonding agents on the repair bond strength of different resin-based restorative materials by microtensile bond strength (μTBS) testing protocol. Materials and Methods: 24 Grandio SO(VOCO) and 24 Filtek Z250(3?M) resin composite blocks were prepared. Half of the samples (N?=?12) were diamond bur-roughened and the other half (N?=?12) were sandblasted by 50?μm aluminum oxide particles. They were further divided into four sub-groups (n?=?3) and received the following: Sub-Group1: Adper Single Bond2 (Etch&Rinse) (3?M); Sub-Group2: Clearfil SE (Self-etch) (Kuraray); Sub-Group3: Beauty Bond (HEMA-free all-in-one) (Shofu); Sub-Group4: All Bond3 (HEMA-free, hydrophobic, etch&rinse) (Bisco). The samples were repaired by Filtek Z250 to form a block. All of the resultant sub-groups combinations consisted of one of the composite type, surface treatment type, and adhesive systems. A total of 18 groups were prepared including 2 homogeneous blocks. They were thermocycled and μTBS measurements were performed. Data were statistically analyzed with Kruskall–Wallis and Mann–Whitney U tests. Results: The experimental regroups’ μTBS reached to 34.67–66.36% and 43.44–95.52% of the cohesive bond strength for Grandio SO and Z250, respectively. The pre-existing composite type is found to be statistically important. When the surface is bur-finished Grandio performed better; when air-abrasion is considered Z250 showed higher bond strength. All-in-one adhesive system produced the weakest bond strength at all parameters. Conclusion: It may be suggested that when the pre-existing composite is unknown, air-abrasion may be performed with etch&rinse or two-step self-etch adhesives.     

Strengthen adhesion between zirconia and resin cement using different surface modifications

The aim of this research was to assess the influence of different surface modifications on the bond strength between resin cement and zirconia ceramics. Eighty-four zirconium samples were prepared. Four different surface treatments were applied; nano-alumina coating, 2 minutes gas-phase fluorination, 50 μm alumina airborne-particle abrasion, and 50 μm airborne-particle abrasion + 2 minutes gas-phase fluorination. Then specimens were bonded to resin cement. Half of the samples were then incubated in 37°C distilled water for 24 hours. The remaining samples were subjected to thermocycling for 5000 cycles. Shear-bond strength testing was applied at a cross head speed of 5 mm/s. Two-way ANOVA was used in comparison between groups. There is a significant difference between the groups with 5000 cycles and the groups with 24 hours of water cycling. The highest shear-bond strength values were observed in the groups with airborne-particle abrasion + 2 minutes fluorination (27.57 MPa) and nano-alumina coating (26.45 MPa) which were not subjected to thermal cycling. Nano-alumina coating of the zirconia surface and the 2 minutes gas-phase fluorination method following airborne-particle abrasion process increased bond strength between resin cement and zirconia.     

Efficacy of different surface treatments and universal adhesives on the microtensile bond strength of bulk-fill composite repair

Abstract

The purpose of this in vitro study was to evaluate the influence of different surface treatments and aging on the microtensile bond strength (μTBS) of bulk-fill composite resins. Bulk-fill composites (Filtek One; 3M ESPE) randomly received five different surface treatments: (1) no treatment, control, (2) 37% phosphoric acid etching (PA), (3) 9% hydrofluoric acid etching (HF), (4) air-borne particle abrasion with 50-μm alumina particles (Al₂O₃), (5) tribochemical silica coating (CoJet). Following, the specimens were divided into three subgroups according to universal adhesive applied: Clearfil Universal Bond (CU; Kuraray), Prime&Bond Universal (PBU; Dentsply Sirona), or Single Bond Universal (SBU; 3M ESPE). A nanofill composite (Filtek Ultimate; 3M ESPE) was employed as a repair. Bonded specimens were stored in water for 24?h at 37?°C or thermal aged, then subjected to the μTBS test. Additionally, specimens were analyzed with a contact profilometer and were evaluated with scanning electron microscopy. Control and PA treatments were showed the lowest µTBS (p?<?0.05), and there was no significant difference between these two groups (p?>?0.05). Al₂O₃ and CoJet treatments generally exhibited a similar influence on µTBS values. In addition, a correlation was found between surface roughness and bond strength (r?=?0.831). CoJet resulted in significantly higher repair µTBS values when compared to the other surface treatments. In addition, the use of silane-containing universal adhesive was increased the cohesive failure rate and maintained the repair µTBS values after thermocycling.