The shear bond strength of repaired high-viscosity bulk-fill resin composites with different adhesive systems and resin composite types

This study compared the effect of different adhesive systems and composite resins on the shear bond strength (SBS) of repaired high-viscosity bulk-fill composites(Tetric EvoCeram Bulk Fill) and investigated failure modes. One hundred twenty cylindrical bulk-fill composite blocks (diameter 5?mm) were fabricated and thermocycled for 5000 cycles (5–55?°C). Specimens were roughened by diamond bur and divided into 8 groups (n?=?15). Bulk-fill blocks were repaired with the same material or nanohybrid composite resin(Tetric EvoCeram Nanohybrid) (diameter 3?mm) using different adhesive systems:Tetric N-Bond Universal (TSE);37% phosphoric acid etching?+?Tetric N-Bond Universal (TER); Clearfil SE Bond (CSE); 37% phosphoric acid etching?+?Adper^TMSingle Bond 2(SB). After repair procedures, all specimens were thermocycled again. The shear bond strengths were measured for all specimens using a universal test machine (crosshead speed of 1?mm/min). Cohesive strengths of bulk-fill composites were measured and described as control group. Debonded surfaces were observed with a stereomicroscope under 10x magnification to determine mode of failure. The SBS data of all groups was statistically analyzed by two-way ANOVA and Bonferroni correction test (p?<?0.05). The specimens repaired with bulk-fill composites showed significantly higher SBS values (25.86?±?5.74, 27.05?±?4.93, 24.49?±?6.95MPa) than those with nanohybrid composites (20.41?±?3.70, 22.08?±?6.37, 18.74?±?6.40?MPa) for TER,CSE,SB, respectively (p?<?0.05). There were no significant differences in SBS according to the type of adhesive systems for both repair materials (p?>?0.05). The predominant mode of failure was a mixed type in the restorative material except for the ones repaired with nanohybrid composites using Adper^TMSingle Bond 2. High-viscosity bulk-fill composites could be successfully repaired with the same materials. SBS of repaired bulk-fill composites reached cohesive strength for all tested groups.     

The effect of different bonding protocols on the repair microshear bond strength of water-stored CAD/CAM resin composite

This study evaluated the repair microshear bond strength (μSBS) of water stored CAD/CAM resin composite under eight different surface treatments using a silane-containing universal adhesive in etch-and-rinse and self-etching modes. In total, 48 CAD/CAM resin composite slices were prepared from Lava Ultimate CAD/CAM blocks and stored in water for 6 months. The slices were assigned into 8 main groups, according to surface treatments (no treatment, no-treatment/silane, surface grinding, surface grinding/silane, sandblasting, sandblasting/silane, silica coating and silica coating/silane). Each main group was divided according to the universal adhesive application mode (either the etch-and-rinse mode or the self-etch mode). Each slice received 6 resin composite micro-cylinders (0.8 × 1 mm). Micro-shear bond strength was run at 0.5 mm/min crosshead speed until failure. Treated surfaces were examined using SEM. Bond strength data were statistically analyzed using Two-Way ANOVA/Tukey HSD post hoc test. Only ‘surface treatment’ significantly affected the repair μSBS (p ? 0.001). Parameters ‘Adhesive application mode’ and ‘surface treatment × adhesive mode’ showed no significant effect on μSBS (p = 0.458 and p = 0.286 respectively). Regardless of the adhesive application mode, silica coating showed the highest μSBS (21.6 ± 6.8 MPa), while sandblasting/silane showed the lowest μSBS (13.0 ± 6.1 MPa). Regardless of adhesive application mode, the use of silica coating to treat the water-stored CAD/CAM resin composite surfaces is crucial to improve the repair bond strength.     

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.     

Bond strength of repaired composite resins: surface treatments,adhesive systems,and composite type

The aim of the present study was to investigate the effects of three different surface treatments and two different adhesives on the microtensile bond strength (μTBS) of repaired composites using the same or different type of resin. Twenty-four nano-hybrid (Ceram X mono-C) and 24 nanofilled (Filtek Ultimate-F) composite discs were prepared. The specimens were aged with 5000 thermocycles and randomly divided into groups according to the surface treatment methods: (a) phosphoric acid (b) Er:YAG laser and (c) aluminum trioxide particle (air abrasion). Fresh composite resins (C and F) were added to the treated surfaces with two different adhesives (two-step and one-step self-etch adhesives). Then, the specimens were aged again. The stick-shaped specimens were prepared from the discs (n = 25) and the sticks were subjected to the μTBS test. Results indicated that significant differences were found in μTBS values among the surface treatment methods. In the C groups, the highest μTBS value (41.3 ± 8.3 MPa) was recorded in the air abrasion and one-step self-etch adhesive group, which were repaired with the same kind of composite. In the F groups, the highest μTBS value was observed in the air abrasion and one-step self-etch adhesive (37.6 ± 12.3 MPa) group. The treatment with air abrasion is more effective than the others, and it may be suggested for composite repair.     

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.     

Effect of different adhesive protocols on bond strength between composite resins for indirect use and repair materials

Abstract

The aim of this work is to evaluate the effect of different adhesive protocols on the bond strength (SBS) of composite resin for indirect use to repairs of bulk-fill or conventional nanoparticulated composites. Forty-eight cylindrical specimens of composite resin for indirect use were prepared, aged, and randomly divided into four groups (n?=?12), a control group without any adhesion protocol, and three experimental groups: Silane?+?Scotch Bond Multipurpose adhesive (S?+?SBMP), Tetric N Bond Universal (TBU), and Single Bond Universal (SBU). The treated surfaces were restored using two different composite resins: Filtek Bulk-Fill or Filtek Z350XT. Then, the specimens were submitted to the SBS test, and the resultant data were analyzed with ANOVA on ranks test and Tukey’s test (α?=?0.05). There were no significant differences between the two types of resins used as repair material. For both resins, the groups treated with S?+?SBMP obtained the highest values (p?<?0.001). Groups TBU and SBU did not have statistically significant differences between them. Pre-treatment with a silane coupling agent and a layer of a hydrophobic adhesive can improve the bond strength of repairs performed on a composite resin for indirect use.     

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.     

Influence of post-etch cleaning and silane heat treatment on resin bond strength to silica-based leucite: an in vitro study

Adhesive cementation of bonded all-ceramic restorations is critical for their long-term clinical performance. The objective of this study was to evaluate the role of post-etch cleaning (PEC) and silane heat treatment on the micro-tensile bond strength of silica-based leucite (SBLE) ceramic when bonded to composite resin. Twenty-four blocks of SBLE ceramic (HeraCeram Press®, Heraeus Kulzer GmbH Grüner Weg 11 63450 Hanau) were fabricated and bonding surfaces were etched using 9.5% hydrofluoric acid. Six experimental groups were made from the various surface treatment combinations including: PEC (37.5% phosphoric acid for 1 min, rinsed with water for 20 s and ultrasonic bath immersion), silane application and silane heat treatment (100 °C for 5 min). An adhesive resin and a light-cured restorative composite were used to bond the ceramic and composite resin blocks under standard conditions. Three hundred and sixty specimen sticks (8 × 1 mm²) were subjected to micro-tensile testing. The means of the micro-tensile bond strength (μ-TBS) were analysed with ANOVA and Tukey–Kramer multiple comparison test. The specimens tested were assessed for mode of failure using scanning electron microscopy. The highest μ-TBS value (38.25 ± 3.40 MPa) of the specimen was achieved by PEC and heated silane. PEC and silane application showed statistically significant improvements in the μ-TBS (p < 0.01). The mean maximum difference was due to PEC (18.91 ± 3.70 MPa). In the surface treatment of SBLE ceramics, PEC had the most significant factor which affected the μ-TBS of resin composite.     

The influence of retention hole and adhesive systems on the shear bond strengths of resin composite to amalgam

The aim of the study is to evaluate the influence of surface-treatment methods with and without the use of a retention hole on the shear bond strength of a resin composite adhered to amalgam using an adhesive system. Amalgam specimens were divided into six groups. Group 1 (Bur) specimens were roughened with a diamond bur, Group 2 (Al₂O₃) specimens were sandblasted with a 50?μm aluminum oxide powder, Group 3 (CoJet^®) specimens were sandblasted with 30?μm CoJet^® Sand, Group 4 (Bur?+?Rh) specimen surfaces were prepared with a retention hole 1?mm in diameter and 1?mm deep and roughened with a diamond bur, Group 5 (Al₂O₃?+?Rh) specimens were also prepared with a retention hole and sandblasted with 50?μm aluminum oxide powder, and Group 6 (CoJet^®?+?Rh) surfaces were prepared with a retention hole and sandblasted with 30?μm CoJet^® Sand. Resin composite cylinders were bonded onto the amalgam surfaces using Xeno^® IV, Optibond? All-In-One, Clearfil? SE Bond, Adper? Single Bond Plus, and Scotchbond? Multi-Purpose adhesive systems. In addition, silane (Monobond S) was used for Groups 5 and 6. The shear bond was determined and statistically analyzed using two-way analysis of variance and post hoc Tukey’s tests (p?≤?0.05). The surface treatment significantly affected the shear bond strengths of the adhesive systems. The shear bond strengths of Optibond? All-In-One (2.661?±?0.48?MPa) in Group 1 and Scotchbond Multi-Purpose (3.818?±?0.98) in Group 4 were significantly higher than those of the other adhesive systems. Silica coating of the amalgam surface significantly improved the shear bond strength of the resin composites. The addition of a retention hole on the amalgam affects the bonding strength of the composite adhesion.     

Effect of surface conditioning methods,adhesive systems and resin composite on repair strength of dimethacrylate and silorane resin composites

This study evaluated the effect of surface conditioning methods and adhesive systems on the repair bond strength of resin composites. Specimens (FLS: Filtek LS) (N = 144) were prepared using a silicone matrix. The specimens were stored in distilled water and then were randomly divided into the twelve groups (n = 12) according to the surface conditioning method (unground or diamond bur) and adhesive system (no adhesive, LS: Filtek LS, AS: Adper Scotchbond SE Plus) and resin composite (FLS: Filtek LS; FS: Filtek Supreme). The specimens were fixed in an hourglass-shaped silicone matrix and the other half of the specimen was restored. Hourglass-shaped specimens (n = 12) were used as positive control to measure the cohesive strength of the resin composite (Filtek LS). Microtensile bond test was performed (0.5 mm/min) and failure types were analyzed. Data were analyzed using two-way analysis of variance, Tukey’s and Dunnett’s tests (α = 0.05). Adhesive protocol and resin composite significantly affected the results (p < 0.05). For the FS composite, the highest results were obtained using LS adhesive with (18.4 ± 7.7) and without (18.8 ± 4.8) bur roughening. For FLS composite, the highest results were obtained using AS adhesive with (33.2 ± 7.1) and without (25.7 ± 3.6) bur roughening. Without the use of adhesive resin, significantly lower bond strength results were observed with both LS (5 ± 2.1, 4.5 ± 1.5) and FLS (2.2 ± 1.2, 4.4 ± 1.1) for unground and diamond bur roughened groups, respectively (p < 0.0001). Cohesive strength of the FLS (52.3 ± 7.6) was significantly higher than any of the repaired groups (p < 0.0001). FS–LS combination and the groups repaired without adhesive presented more adhesive (Type I) failures.     

Efficiency of different repair kits on bonding to aged dental resin composite substrates

ObjectiveTo assess the efficiency of intraoral repair kits on the tensile bond strength (TBS) of resin composites (RCs) to aged RC substrates.Methods840 aged (six months, 37 °C, distilled water) RC substrates (Tetric EvoCeram) were air-abraded (CoJet) with and without following phosphoric acid contamination or treated with silicon carbide (SiC) grinding paper. Seven repair kits were used as intermediate agents (Embrace First-Coat, CLEARFIL CERAMIC PRIMER, Tokuso Ceramic Primer, Monobond Plus+Heliobond; Scotchbond Universal, One Coat Bond and visio.link) for conditioning. Specimens were repaired using two direct RCs (Clearfil Majesty ES2 and Clearfil Majesty Posterior), stored in distilled water (37 °C, 24 h) and thermal aged (5 °C/55 °C, 10,000 cycles). The cohesive strength of the repair RCs (N=40) served as control and was determined by applying the RCs on the fresh polymerized substrates, followed by thermal-aging procedure. TBS and failure types were determined and evaluated with three-/one-way ANOVA, and chi-square test (p<0.05).ResultsThe highest influence on the TBS was exerted by the intermediate agent (repair kit) (partial eta squared η_P²=0.320, p<0.001), while the impacts of the repair RC (η_P²=0.017, p<0.001) and surface pre-treatment (η_P²=0.015, p=0.003) were significant but low. Except for Embrace First Coat and Tokuso Ceramic Primer, phosphoric acid contamination after air-abrasion maintains the TBS.ConclusionsAir-abrasion induced superior TBS compared with grinding the surface with SiC paper prior to repair. Tested universal adhesives as well as the combination between a universal primer and an adhesive were in-vitro efficient intermediate agents for repairing aged RCs.     

Effects of chemical and physico-chemical surface conditioning methods on the adhesion of resin composite to different mineral trioxide aggregate based cements

This study investigated the adhesion of resin composite to mineral trioxide aggregate based cements after different chemical and physico-chemical surface conditioning methods. Mineral trioxide aggregate based cements (Biodentine, ProRoot MTA, Imicryl MTA) were embedded in Teflon disks (N?=?180). After storing at 37?°C at 100% humidity for 72?h, substrate surfaces were polished using silicon carbide papers. Specimens were allocated to 3 groups to be conditioned with one of the following (n?=?15 per group): a) Adhesive resin (Clearfil SE Bond, CSE), b) Adhesive resin (Adper Single Bond 2, SB2), c) air-abrasion with 30?μm alumina coated with silica?+?silane?+?adhesive resin (ALB), d) no surface conditioning, control group (CON). Microhybrid resin composite (Filtek Z250) was applied on the conditioned substrate surfaces and photo-polymerized. After storage at 37?°C at 100% humidity for 24?h, adhesive interfaces were loaded under shear (1?mm/min) in a universal testing machine. After debonding failure types were analyzed. Data were analyzed using 2-way ANOVA and Tukey’s test (alpha = 0.05). SBS results were significantly affected by surface conditioning (p?<?0.05) and materials (p?<?0.05). Interaction terms were significant (p?<?0.05). Biodentine-ALB resulted in significantly higher SBS values (3.96?±?1.24) compared to those of other combinations, while ALB and SB2 resulted in no significant difference for ProRoot MTA and Imicryl MTA (p?>?.05). CSE (1.36?±?0.5- 1.98?±?0.76) did not significantly increase SBS for all MTA materials compared to the control group (0.8?±?0.52 – 2?±?0.91) (p?>?9.05). While CON groups resulted in exclusively adhesive failures, ALB presented the highest incidence of mixed failures for all materials tested (60–100%).     

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.     

Bonding effectiveness of different dentin conditions on etch-and-rinse mode of two universal adhesives: the confocal laser scanning and shear bond strength

The purpose of this study was to evaluate the shear bond strength and the morphological differences of adhesive/dentin interface of two one-step universal adhesives to dentin using different dentin-conditioning methods with etch-and-rinse mode. Ninety-six dentin specimens were randomly divided into two groups based on application of two adhesives and assigned to three subgroups according to different dentin conditioning (wet-bonding; air-dried; rewetting). After etching and rinsing, experimental dentin conditioning was conducted on the etched dentin specimens. All specimens were subjected to shear bond strength testing using a universal testing machine, and all data were statistically analyzed using two- way analysis of variance with Tukey’s post hoc test. All debonded specimens were examined for fracture pattern by scanning electron microscopy (SEM). Adjunctively, one specimen per group was prepared by the same processing and longitudinally sectioned. Then, the infiltration ability of adhesives into dentin was examined by observing the interface using confocal laser-scanning microscopy (CLSM). Wet and Rewet groups exhibited significantly higher shear bond strength than dry groups on the etch-and-rinse system, regardless of different adhesives. The bond strength between wet and rewet groups showed no significant difference in Tukey’s test. Analysis of failure surface using SEM showed that predominant failure patterns were mixed in both the wet-bonding group and dry-bonding group. CLSM presented that resin penetration into etched dentin was enhanced similarly in wet and rewet group. Application of rewetting agents on dried dentin increased the bonding performance of universal adhesives on etch-and-rinse mode.     

Efficacy of uncommon surface treatment methods on titanium in order to improve bond strengths for adhesive cementation

The aim of this study is to comparison of effects of uncommon surface treatments, especially new alternatives on the adhesive strength between resin and titanium surfaces. Fifty-five titanium disks were prepared and they were separated into 5 groups as follows: (1) Control group; (2) Tribochemical treatment group in the laboratory; (3) Tribochemical treatment group in the clinic; (4) Acid etch group; and (5) Nd:YAG Laser-irradiated group. Surface roughness of the specimens was measured using a profilometer, and the topographic patterns were observed by scanning electron microscope. After these tests, resin cement was applied to the titanium samples. Shear bond test was performed via a universal testing machine at a crosshead speed of 0.5 mm/minute. In addition, the correlation between the surface roughness and bond strength was checked using Spearman correlation test (0.01 level). The highest surface roughness value was observed for the acid etch group (1.53 μm). The highest mean shear bond strength was recorded with the tribochemical procedure group in the laboratory (13.74 MPa) and the lowest with the control group (3.69 MPa). A positive correlation was found between the bond strength and surface roughness for all groups. All of the surface treatment methods that were used in present study increased the bond strength between resin and titanium except for the laser group.     

Influence of desensitizing procedures on adhesion of resin cements to dentin

This study evaluated the effect of two desensitizer agents with different contents and Nd:YAG laser irradiation on the shear bond strength (SBS) of adhesive resin cements to dentin. New treatment options of Nd:YAG laser irradiation and tetracalcium phosphate-containing agent applications were compared with routinely used glutaraldehyde-containing agents. One hundred and twenty human, caries-free premolars were embedded in acrylic resin blocks 2 mm below the cementoenamel junction. Buccal surfaces of the teeth were ground to expose dentin. The specimens were randomly assigned into three different surface treatments (desensitizing agents, Nd:YAG laser) and the control, then into three different adhesive resin cement applications (n = 10). Resin cements (Panavia SA cement (PA), Panavia SA cement with Clearfil Universal Bond (PACU), and Multilink N (MN)) were applied to the conditioned teeth surfaces using Teflon tubes. The specimens were thermocycled (5000 cycles, 5–55 ± 1 °C, dwell time 30 s). The SBS test was performed in all groups. The results were submitted to two-way ANOVA and Tukey HSD tests (p < .05). Further, SEM analysis was performed on the dentin surfaces. SBS values were significantly difference among the surface treatment groups and also among adhesive resin cement groups (p < .05). The specimen cemented with PA showed lower SBS values than PACU- and MN-applied specimens. The highest SBS value was obtained in the Nd:YAG laser group which was cemented with PACU cement. The lowest SBS value was obtained in the control group which was cemented with PA cement. In addition, SEM evaluation revealed that desensitizing agents and Nd:YAG laser occluded dentin tubules.     

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 adhesive application on the shear bond strength of refrigerated and pre-heated of different composite resins to orthodontic molar tubes

Objective: To evaluate the effect of adhesive application on the shear bond strength (SBS) of orthodontic tubes to acid-etched human enamel using different temperatures and orthodontic composite resins. Methods: One hundred and twenty metal tubes were bonded to human third molars, which were randomly divided into three groups depending on the composite used: Transbond XT (XT); Transbond Supreme LV (LV); and Light Bond (LB). Each group was divided into four subgroups depending on the temperature (5°, 20°, 40°, and 60°) applied to the composite before cementing. For each experimental subgroup, half the specimens were bonded in combination with XT Primer. After 72?h, a SBS test was performed using a universal testing machine. Statistical analysis was performed using ANOVA, post hoc intergroup comparisons, chi-square test, and linear regression. Two representative molar surfaces from each subgroup were assessed under Scanning electron microscope. Results: The composite type only influenced XT regarding LB. The use of adhesive does not affect the SBS values of any composite. The flowable composites with adhesive containing zirconia (LV) as a filler showed lower SBS when cooled to 5?°C and when increases the temperature from 40?°C. Whether adhesive was used or not, composites with silica as filler (LB) showed lower SBS at 60?°C and increased to 5?°C. Conclusions: For all composites, from 20?°C, SBS values tend to increased and started to decline at 40°C except when adhesive is applied to the quartz-filled composite, which continues to increase, and the silica-filled composite without adhesive, which tend to decreases from 5?°C.     

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.     

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.