Effect antioxidants application on microshear bond strength of universal adhesive to bleached enamel

Objective: This study used the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) method to evaluate the percentage of antioxidant activity (%AA) of green tea (GT) and sodium ascorbate (SA) gel in three concentrations (10%, 20% and 30%), and the influence of these concentrations on the microshear bond strength (μ-SBT) values of bleached enamel, using 10% carbamide peroxide (CP).Materials and methods: Eighty intact third molars were selected to perform the μ-SBT test, and were randomly divided into eight experimental groups: G1: positive control – no treatment; G2: negative control – bleached with CP; G3: PC +10% GT; G4: PC +20% GT; G5: PC +30% GT; G6: PC +10% SA; G7: PC +20% SA and G8: PC +30% SA. After applying the treatments, adhesive procedures were performed using Single Bond 2 and Filtek Z350XT. After 24 h, the samples were tested in a universal testing machine until fracture. The %AA was assessed in triplicate by DDPH method using a UV–VIS spectrophotometer.Results: In the μ-SBT, ANOVA revealed no significant difference between the antioxidants evaluated (p = .625), but did reveal significant effects of the concentrations studied (p = .007). A negative correlation was observed between μ-SBT and solution concentrations. The values of %AA were from 90.58 to 96.75.Conclusions: The reverse results occurred in μ-SBT values, only when the antioxidants were used in a 10% concentration and, %AA did not influence μ-SBT.

Effect of thermo-mechanical cycling and chlorhexidine on the bond strength of universal adhesive system to dentin

Introduction Due to an increase in patient awareness and search for aesthetic treatments, dental bleaching is a frequent and safe procedure in clinical practice for the removal of stains [1]. Bleaching agents are known to adversely affect the bond strength between resin composite and tooth surface, when adhesive procedures are performed immediately after tooth bleaching [2]. The reduction in bond strength is related to the presence of residual oxygen, a sub product of hydrogen peroxide that remains on the tooth surface and which may interfere with infiltration of the resin in the dentine tubules and inhibit the polymerisation of resin monomers [3]. Antioxidant agents like sodium ascorbate, grape seed extract and green tea may be used as an alternative to delay the restorative procedure due to their potential as reversers of these adverse effects [2]. This study aims to assess the influence of different antioxidant agents on the bond strength of restored bleached teeth. Materials and methods The present study was approved by the Ethics Committee of Instituto Universitário Egas Moniz. Fifteen human permanent molars were sectioned into identical halves that were randomly distributed between five groups (n = 6): unbleached control group (CG), bleaching + resin composite bonded immediately (G1), bleaching + sodium ascorbate (G2), bleaching + grape seed extract (G3) and bleaching + green tea (G4). G1, G2, G3 and G4 were bleached for 4 h/day for a 7-day period. After bleaching, G1 samples were immediately restored with an adhesive system and a resin composite, in G2 samples a 10% sodium ascorbate gel was applied, in G3 a 5% grape seed extract and in G4 a 5% green tea, all applied for 15 min. After these antioxidants, G2, G3 and G4 were immediately restored. After 24 h, samples were sectioned in order to obtain 1.0 (± 0.3) mm2 microspecimens. The microspecimens were tested in a universal testing machine at a speed of 0.5 mm/min. Data were analysed by using a two-way ANOVA, at a significance level of 5%. Results G1 group (bleaching only) recorded the lowest mean bond strength value (9.5 (± 1.2) MPa) and it was significantly lower than the control group (CG) (19.3 (± 2.7) MPa) (p = .001). Groups in which sodium ascorbate (G2) (19.2 (± 1.3) MPa), grape seed extract (G3) (16.5 (± 0.8) MPa) and green tea (G4) (16.7 (± 2.0) MPa) were applied presented significantly higher bond strength values when compared to bleaching only (G1) (p < .001). When comparing the antioxidant agents, G2 (10% sodium ascorbate) exhibited significantly higher mean bond strength values when compared to G3 (5% grape seed extract) (p = .016). Discussion and conclusions Treatment of the enamel surface with antioxidant agents such as sodium ascorbate, grape seed extract and green tea following the bleaching procedure and immediately before the restorative procedure can reverse the compromised bond strength. These alternative strategies are effective and may be used instead of delaying the procedure.

Profile of a 10-MDP-based universal adhesive system associated with chlorhexidine: Dentin bond strength and in situ zymography performance

Bleached enamel reversal using grape seed extract, green tea, curcumin-activated photodynamic therapy, and Er: YAG on microleakage and bond integrity of composite material bonded to the enamel surface

Push-out Bond Strength of Fiber Posts to Intraradicular Dentin Using Multimode Adhesive System

Objectives:The aim of this study was to compare the microshear bond strength (μSBS) of various adhesive systems to dentin.Materials and Methods:In this in vitro experimental study, 60 sound human third molars were divided into four groups. Dentin discs were prepared of middle-third dentin measuring 4 mm in diameter and 2 mm in thickness. Dentin surfaces were bonded with one of the four types of adhesives: (A) Single Bond (3M ESPE), Scotchbond Universal (3M ESPE) in etch and rinse (B) and self-etch (C) modes and (D) Clearfil SE Bond (Kuraray Noritake Dental). After the application of adhesive systems according to the manufacturers’ instructions, composite cylinders (Vit-l-escence) were bonded to dentin surfaces. The μSBS test was performed using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed with one-way ANOVA and Tukey’s test (α=0.05).Results:The μSBS was the highest in self-etch Scotchbond Universal (15.8±6.08 MPa) followed by Clearfil SE Bond (15.24±4.6 MPa), etch and rinse Scotchbond Universal (11.68±4.07MPa) and Single Bond (11.24±3.74 MPa). A significant difference was only found between Single Bond and etch and rinse Scotchbond Universal groups (P=0.04).Conclusion:Based on the results of this study, application of Scotchbond Universal in self-etch mode provides a reliable bond to dentin.

Objectives: The aim of this study was to compare the microshear bond strength (µSBS) of various adhesive systems to dentin.&#x0D; Materials and Methods: In this in vitro experimental study, 60 sound human third molars were divided into four groups. Dentin discs were prepared of middle-third dentin measuring 4 mm in diameter and 2 mm in thickness. Dentin surfaces were bonded with one of the four types of adhesives: (A) Single Bond (3M ESPE), Scotchbond Universal (3M ESPE) in etch and rinse (B) and self-etch (C) modes and (D) Clearfil SE Bond (Kuraray Noritake Dental). After the application of adhesive systems according to the manufacturers’ instructions, composite cylinders (Vit-l-escence) were bonded to dentin surfaces. The μSBS test was performed using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed with one-way ANOVA and Tukey’s test (α=0.05).&#x0D; Results: The µSBS was the highest in self-etch Scotchbond Universal (15.8±6.08 MPa) followed by Clearfil SE Bond (15.24±4.6 MPa), etch and rinse Scotchbond Universal (11.68±4.07MPa) and Single Bond (11.24±3.74 MPa). A significant difference was only found between Single Bond and etch and rinse Scotchbond Universal groups (P=0.04).&#x0D; Conclusion: Based on the results of this study, application of Scotchbond Universal in self-etch mode provides a reliable bond to dentin.

Influence of different etching modes on bond strength and fatigue strength to dentin using universal adhesive systems

INTRODUCTION: Bleaching, although considered as the first choice of treatment for discoloured teeth, can be utilized in conjunction with composite resin bonding or veneering and porcelain laminate veneers, to provide a more esthetic result. AIM: The aim of the ex-vivo study is to obtain a comparative analysis to evaluate the effectiveness of antioxidants on the immediate composite bond strength on bleached enamel surface.MATERIALS AND METHOD: Freshly extracted human permanent maxillary central incisors were selected and prepared for the respective study. All the specimens then were randomly divided into two control groups and three experimental groups, each group consisting of 20 specimens each. Among these were three experimental groups 10% Sodium Ascorbate, 5% Grape Seed extracts (Proanthocyanidin, PA) &amp; 10% Green tea extracts (catechins and epigallocatechin gallate, CA and EG) and two control groups (Positive control &amp; Negative control).RESULTS: When compared to Group 1 (positive control, 26.24 ± 0.90 MPa ), Group 3 (5%Grape seed extract; 32.17 ± 1.52 MPa), Group 4 (10% Sodium Ascorbate; 28.91 ±1.50 MPa ) and Group 5 (5% Green tea extract; 24.10 ± 1.21MPa ) showed significantly higher shear bond strength values.CONCLUSION: The present study indicated that the shear bond strength of the antioxidant group (Group3) is higher than all three experimental groups. In addition, the shear bond strength of the bleached group (Group 2) is significantly lower than all the other groups. This implies that immediate use of antioxidants, contributes in reversal the bond strength of bleached enamel.

Objectives Evaluate the impact of blending Moringa oleifera and Rosemary leaf extracts with hydrogen peroxide (HP) and carbamide peroxide (CP) bleaching agents on dentin microhardness and microshear bond strength of resin-modified glass-ionomer at dentin interface after walking bleach procedure. Methodology Seventy endodontically treated human mandibular premolars were randomly split into three groups. Group I ( n = 10) where no bleaching was done, group II ( n = 30) used 30% HP as intracoronal bleaching agent where the samples equally subdivided into; subgroup A (only HP), subgroup B (HP + M. oleifera leaf extract), subgroup C (HP + Rosemary leaf extract). Group III ( n = 30) used 37% CP and the samples equally subdivided into; subgroup A (only CP), subgroup B (CP + M. oleifera leaf extract), subgroup C (CP + Rosemary leaf extract). Bleaching procedure was performed immediately after restoration with resin-modified glass ionomer restoration. Teeth were sectioned and underwent dentin microhardness and microshear bond strength tests before and after bleaching procedure. Data analysis was done using one-way analysis of variance. Results The results revealed notable decrease in microhardness and microshear bond strength mean values in all subgroups after different bleaching protocols ( P &lt; 0.05). Also, the differences were statistically significant among subgroups received only bleaching agents and others subjected to either M. oleifera or Rosemary leaf extracts treatment with the bleaching agents. Conclusion M. oleifera and Rosemary leaf extracts could reverse the reduced microhardness and bond strength mean values as they can be future candidates to be used as antioxidants after bleaching.

BackgroundThis study aimed to investigate the microshear bond strength of universal bonding adhesives to leucite-reinforced glass-ceramic.MethodsLeucite-reinforced glass-ceramic blocks were polished and etched with 9.5% hydrofluoric acid for 1 min. The specimens were assigned to one of four groups based on their surface conditioning (n = 16): 1) NC: negative control with no further treatment; 2) SBU: Single Bond Universal (3M ESPE); 3) ABU: ALL-BOND Universal (Bisco); and 4) PC: RelyX Ceramic Primer and Adper Scotchbond Multi-Purpose Adhesive (3M ESPE) as a positive control. RelyX Ultimate resin cement (3M ESPE) was placed on the pretreated ceramic and was light cured. Eight specimens from each group were stored in water for 24 h, and the remaining eight specimens were thermocycled 10,000 times prior to microshear bond strength evaluation. The fractured surfaces were examined by stereomicroscopy and scanning electron microscopy (SEM).ResultsAfter water storage and thermocycling, the microshear bond strength values decreased in the order of PC > SBU and ABU > NC (P < 0.05). Thermocycling significantly reduced the microshear bond strength, regardless of the surface conditioning used (P < 0.05). Cohesive failure in the ceramic and mixed failure in the ceramic and resin cement were observed in the fractured specimens. The percentage of specimens with cohesive failure after 24 h of water storage was: NC (50%), SBU (75%), ABU (75%), and PC (87%). After thermocycling, the percentage of cohesive failure in NC decreased to 25%; however, yet the percentages of the other groups remained the same.ConclusionsAlthough the bond strength between resin and hydrofluoric acid-etched glass ceramic was improved when universal adhesives were used, conventional surface conditioning using a separate silane and adhesive is preferable to a simplified procedure that uses only a universal adhesive for cementation of leucite-reinforced glass-ceramic.

Purpose To determine the dentin bonding ability of three new universal adhesive systems under different etching modes using microshear bond strength (μSBS). Materials and methods Futurabond U, Single Bond Universal, and Tetric N-Bond Universal were used in this study. Sixty noncarious human molars were assigned to three groups based on the type of the universal adhesives. Two etching modes (total-etch and self-etch) were employed for each adhesive group. The adhesives were applied on dentin surfaces according to the manufacturer's instructions then composite resin (Z350 XT, nanocomposite) was condensed through a polyethylene tube with a 1 mm internal diameter and 2 mm height attached firmly to dentin surfaces and light cured. All samples were thermocycled for 500 cycles from 5 to 55°C. The μSBS was measured by using universal testing machine at cross-head speed of 0.5 mm/min. The bonded surfaces were examined under a stereomicroscope at magnification ×50 to determine the mode of failure. Dentin slices were prepared for each group to evaluate the resin–dentin interface a resin composite with each adhesive were placed 2 mm thick to form composite core. The segments were sectioned longitudinally and prepared to be examined under scanning electron microscope. Results Among the universal adhesives, Futurabond U and Tetric N-Bond Universal in total-etch mode showed significantly higher μSBS values than in self-etch mode. Single Bond Universal did not show any significant difference in μSBS between the total-etch mode and self-etch mode. Conclusion Performance of universal adhesives was shown to be material-dependent. The results indicate that universal adhesives used on dentine performed better in total-etch mode than self-etch mode.

Teeth bleaching causes an immediate decrease in resin composite bonding ability. This study aimed to investigate the influence of various antioxidants on resin composite bond strength to bleached enamel. One hundred and ten human maxillary incisors were used. A negative control (group A) (n = 10) was assigned (no bleaching-no antioxidant). The remaining teeth were divided into two groups (n = 50) according to the bleaching agent used: group B (40% hydrogen peroxide) and group C (35% carbamide peroxide). Both groups were subdivided into five subgroups (n = 10). A positive control subgroup (no antioxidant) and other four subgroups according to the antioxidant solution used (10% sodium ascorbate, 10% grape seed extract, 10% green tea extract, and 5% alpha-lipoic acid). After resin composite building, the micro-shear bond strength test was performed. Fracture analysis was examined using a stereomicroscope. Statistical analysis was performed using a two-way analysis of variance and Tukey's HSD post hoc test. Bond strength significantly decreased after bleaching and there was no significant difference between bleaching agents (P < .0848). Except for alpha-lipoic acid subgroups, the other antioxidants subgroups revealed significantly higher bond strengths than bleached control subgroups (P < .0001). All antioxidants used except alpha-lipoic acid were effective in the reversal of compromised bonding after bleaching. Immediate bonding procedures after bleaching are requisite when bleaching fails to treat teeth discoloration and the direct composite veneer is considered, also when shades of old composite restorations become mismatched after bleaching and should be replaced. Immediate reestablishment of resin bond strengths after bleaching can be achieved by using several antioxidants without the need for delay.

BackgroundDeterioration in shear bond strength has been reported after immediate bracket bonding following hydrogen peroxide bleaching. This study compared the effectiveness of three antioxidant agents, namely, alpha-tocopherol, green tea extract, and sodium ascorbate, in reversing the bleaching effect and as possible alternatives to delayed bonding.MethodsA total of 105 extracted human premolars were arbitrarily assigned to 7 groups (n = 15 each), including group 1 as the unbleached control group and six experimental groups, which were bleached with 40% hydrogen peroxide in three sessions of 15 min each. In experimental group 2, bonding was performed immediately after bleaching, whereas in groups 3 and 4, bonding was delayed for 1 and 2 weeks, respectively; meanwhile, the specimens were immersed in artificial saliva at 37 °C. Groups 5, 6, and 7 were treated immediately after bleaching with 10% of alpha-tocopherol, green tea extract, and sodium ascorbate solutions, respectively, for 15 min. Specimens were processed using 500 thermal cycles between 5 and 55 °C, with a dwell time of 30 s after 24 h of bracket bonding, and then tested for shear bond strength. The adhesive remnant index was examined to evaluate fracture mode. One-way analysis of variance, Kruskal–Wallis H, and post hoc Tukey’s honestly significant difference tests were used to compare the data. Significant results were subjected to pairwise comparisons with Bonferroni’s correction-adjusted of p values ≤ 0.050.ResultsShear bond strength was significantly lower (p < 0.001) in the immediate bonding and 1-week delay groups than in the control group. However, no significant difference was detected among the 2-week delay, antioxidant-treated, and control groups (p > 0.05).ConclusionsApplication of 10% alpha-tocopherol, green tea extract, or sodium ascorbate for 15 min could restore shear bond strength after 40% hydrogen peroxide bleaching as an alternative to delay in bracket bonding.