Bond Strength Of Adhesive Systems Research Articles

Microtensile Bond Strength of Self-Etch Adhesives on Dentin Treated with Chlorhexidine.

To evaluate the microtensile bond strength of self-etching adhesive systems in dentin treated with 2% chlorhexidine digluconate (CHX). The occlusal surfaces of 20 human molars were removed and divided into eight groups: 1A, Clearfil SE adhesive (SE) with self-etching technique (TS); 1B, SE with TS and previous application of CHX; 2A, Scotchbond Universal (SBU) adhesive with TS; 2B, SBU adhesive with TS and previous application of CHX; 1C, SE with total-etching technique (TT); 1D, SE with TT and previous application of CHX; 2C, SBU with TT; 2D SBU with TT and previous application of CHX. Composite resin (5mm) was applied on the hybridized surface. Samples were subjected to microtensile test and evaluated on Scanning Electron Microscope (SEM) and with energy-dispersive X-ray (EDX). Low values of bond strength were observed in groups 1A (39,77±11,56) and 2A (40,84±12,49) comparing with 1B (22,86±5,18) and 2B (27,02±5,58). TS group presented adhesive type remover fracture while TT groups presented cohesive at the top of hybrid layer. EDX revealed the presence of CHX crystals for TS, which was not found in the TT. The previous application of chlorhexidine on dentin decreased the bond strength of adhesive systems on self-etching technique.

Saliva with different concentrations of enzyme with esterolytic activity, and its effect on the immediate and long-term bond strength of adhesive systems to dentin

The present study evaluated whether different concentrations of albumin would influence the immediate or long-term bond strength of adhesive systems to dentin. Human third molars (N = 90) were sectioned at the dentin-enamel junction to obtain middle dentin occlusal surfaces. After sectioning into discs, the molars were restored with resin composite (Filtek Z250, 3 M/ESPE) by using an etch-and-rinse (Adper Scotchbond Multi-Purpose, 3 M/ESPE) or a self-etch (Clearfil SE Bond, Kuraray) adhesive system. The specimens were then sectioned into beams and stored in artificial saliva containing albumin in regular (100 μg/mL; SA100) or elevated (700 μg/mL; SA700) concentration—both concentrations simulated the range in which this enzyme may be present clinically, depending on the patient's periodontal condition. Beams from the control group (CO) were kept in artificial saliva with no addition of albumin. Half of the beams from each group were stored for 24 h, and the remainder, for 12 months. Then, the microtensile bond strength test was performed, and the failure mode was analyzed (adhesive, cohesive, or mixed). Bond strength data were submitted to the generalized linear model, followed by the Tukey tests, and failure modes were compared using chi-square tests (α = 5%). There were no significant interactions, but there was a significant effect between the albumin concentration (p = 0.015) and the time factor (p = 0.016). The beams stored in SA700 had significantly lower bond strength in comparison with the CO beams, regardless of the adhesive system. At 12 months, the bond strength decreased significantly for all groups. SA700 caused a significant increase in the adhesive failures after 12 months (p = 0.005). It was concluded that the bond strength of both adhesive systems was impaired by the albumin concentration aging.

Effect of Collagen Crosslinkers on Dentin Bond Strength of Adhesive Systems: A Systematic Review and Meta-Analysis.

This study aimed to identify the role of crosslinking agents in the resin–dentin bond strength (BS) when used as modifiers in adhesives or pretreatments to the dentin surface through a systematic review and meta-analysis. This paper was conducted according to the directions of the PRISMA 2020 statement. The research question of this review was: “Would the use of crosslinkers agents improve the BS of resin-based materials to dentin?” The literature search was conducted in the following databases: Embase, PubMed, Scielo, Scopus, and Web of Science. Manuscripts that reported the effect on the BS after the use of crosslinking agents were included. The meta-analyses were performed using Review Manager v5.4.1. The comparisons were performed by comparing the standardized mean difference between the BS values obtained using the crosslinker agent or the control group. The subgroup comparisons were performed based on the adhesive strategy used (total-etch or self-etch). The immediate and long-term data were analyzed separately. A total of 50 articles were included in the qualitative analysis, while 45 articles were considered for the quantitative analysis. The meta-analysis suggested that pretreatment with epigallocatechin-3-gallate (EGCG), carbodiimide, ethylenediaminetetraacetic acid (EDTA), glutaraldehyde, and riboflavin crosslinking agents improved the long-term BS of resin composites to dentin (p ≤ 0.02). On the other hand, the use of proanthocyanidins as a pretreatment improved both the immediate and long-term BS values (p ≤ 0.02). When incorporated within the adhesive formulation, only glutaraldehyde, riboflavin, and EGCG improved the long-term BS to dentin. It could be concluded that the application of different crosslinking agents such as carbodiimide, EDTA, glutaraldehyde, riboflavin, and EGCG improved the long-term BS of adhesive systems to dentin. This effect was observed when these crosslinkers were used as a separate step and when incorporated within the formulation of the adhesive system.

Fatigue bond strength of dental adhesive systems: Historical background of test methodology, clinical considerations and future perspectives.

Numerous laboratory evaluations have been conducted since Dr. Rafael Bowen introduced a method for determining the bond strengths of adhesive systems to dental substrates in 1965. Most of the past studies have been conducted using static bond strength tests, such as shear and tensile bond strength testing with either macro or micro sized specimens. These static bond strength tests are conducted using a monotonically increasing load in which stress is applied continuously until failure occurs. Although the type of stress that develops in static bond strength tests is not typically encountered in clinical situations, over the years clinicians have based their choice of adhesive systems for use in daily practice on the results of such tests. However, some well-known researchers have reported that the results obtained from static bond strength testing may have limited clinical relevance and should not be used only by themselves to make recommendations for clinical use. In clinical situations, restorations undergo cyclic stress during mastication at stress levels well below the breaking stress used in static bond strength tests. Thus, dynamic bond strength tests, using cyclic loading, should be more clinically relevant than static bond strength tests. Over 15 years, a testing method designed to assess fatigue bond strengths of dental adhesive systems has been developed through inter-collegial and international collaborative efforts. This review discusses the development of fatigue bond strength testing methodology, provides both a historical perspective and current information regarding available testing data for all categories of adhesive systems to enamel and dentin and perspectives on the future development of both adhesive systems and testing methods.

Bond Strength of Adhesive Systems to Calcium Silicate-Based Materials: A Systematic Review and Meta-Analysis of In Vitro Studies.

Since the adhesion of resin composites to calcium silicate-based cement is considered challenging. Therefore, the best adhesion strategy should be indicated. This review aimed to assess the effect of different adhesive systems on the bond strength of resin composite to calcium silicate-based cement through a systematic review and meta-analysis. The subsequent PICOS framework used was: population, calcium silicate-based cement; intervention, use of self-etch adhesive systems; control, use of total-etch adhesive systems; outcome, bond strength; study design, in vitro studies. The literature search was conducted independently by two reviewers up to 18 February 2021. Electronic databases (PubMed, ISI Web of Science, SciELO, Scopus, and Embase) were searched for applicable articles. In vitro manuscripts studying the effect of adhesive systems on the bond strength of calcium silicate-based cement were considered. The meta-analyses were performed using Review Manager Software version 5.3.5 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark). Bond strength comparisons were made considering the type of calcium silicate-based cement (Mineral Trioxide Aggregate (MTA), Biodentine™, or TheraCal LC®). A p-value < 0.05 was considered statistically significant. A total of 7321 studies were retrieved in databases searched. After full-text evaluation, 37 eligible papers were assessed for qualitative analysis, leaving a total of 22 papers for the quantitative analysis. According to the meta-analysis, the bond strength values of resin composite materials to MTA and TheraCal LC® cement were favored when a total-etch adhesive system was used (p ≤ 0.02). On the other hand, the meta-analysis of the bond strength of resin-based materials to Biodentine™ calcium silicate-based cement was similar between both approaches (p = 0.12). The in vitro evidence suggests that the bond strength of resin-based materials to both MTA and TheraCal LC® cement was preferred by using the total-etch adhesive strategy. However, when bonding to Biodentine™, the use of self-etch or total-etch strategies displayed promising results. Given the lack of evidence related to the chemical interaction of self-etch adhesive materials with the bioceramics, if self-etch adhesives are used for bonding resin-based restorations to calcium silicate-based cement, a pretreatment with phosphoric acid could be recommended.

Effect of mold enclosure and chisel design on fatigue bond strength of dental adhesive systems.

To examine the effect of mold enclosure and chisel design on macro shear fatigue bond strengths of dental adhesive systems. The fatigue bond strength testing was conducted with two commercially available dental adhesive systems, (1) OptiBond eXTRa and (2) Scotchbond Universal, for bonding a resin composite (Filtek Supreme Ultra) to both enamel and dentin using a mold enclosure and a non‐mold enclosure with a knife‐edge and two sized notched‐edge chisel assemblies for loading. As a loading reference for the fatigue testing, macro shear bond strengths of the adhesive systems to enamel and dentin were conducted using a mold enclosure and a knife‐edge chisel assembly. The shear bond strengths with the mold enclosure using knife‐edge chisel assembly did not exhibit a significant difference between the adhesive systems for either enamel or dentin. The fatigue bond strengths of bonded specimens demonstrated significant differences when comparing the mold enclosure and non‐mold enclosure, but not between knife‐edge and notched‐edge chisel assemblies. The fatigue bond strengths of dental adhesive systems demonstrated significantly higher values when using mold‐enclosed bonded specimens than a non‐mold enclosure, regardless of type of chisel assembly.

Vital Bleaching Influences the Bond Strength of Adhesive Systems to Enamel and Dentin: A Systematic Review and Meta-Analysis of In Vitro Studies.

This systematic review evaluates the influence of vital bleaching on the bond strength of adhesive systems to enamel and dentin. This review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). In vitro studies comparing the bond strength of bleached and unbleached enamel and dentin were searched at the electronic databases-PubMed/MEDLINE, Scopus, and Web of Science-with no limit on year or language. The studies were screened and had data extracted by two reviewers independently. Bond strength data were meta-analyzed using the inverse variance method and the random effect model (p≤0.05). The electronic search provided 4941 eligible studies, and 52 were included in the systematic review and the meta-analysis. The global meta-analysis showed that bleaching impairs the bond strength of adhesive systems to enamel and dentin (p<0.001; mean difference [MD]: -0.96; confidence interval [CI]: -1.18 to -0.73), regardless of the bleaching agent (p<0.001; MD: -9.98; CI: -1.37 to -0.58) or substrate (p<0.001; MD: -0.89; CI: -1.12 to -0.66). The detrimental effect of bleaching on bond strength was not observed after two and three weeks after bleaching (p=0.1; MD: -0.39; CI: -0.84 to 0.65; and p=0.18; MD: -0.99; CI: -2.45 to 0.47, respectively). This systematic review and meta-analysis demonstrated that vital bleaching impairs the bonding of adhesive systems to enamel and dentin, and this adverse effect persists for two weeks.

Effect of diode laser-assisted bleaching on the bond strength of different adhesive systems to enamel: Interfacial SEM analysis.

The aim of this study was to investigate the effectiveness of diode laser-assisted bleaching on the shear bond strength (SBS) of different adhesive systems to enamel and examine the adhesive enamel interface under scanning electron microscope (SEM). 180 incisor teeth were randomly divided into three bleaching groups: (1) Unbleached control group, (2) Opalescence Boost (OB) 40%, and (3) Diode laser-assisted LaserWhite20 (LW20) 45%. After bleaching, each group was divided into two subgroups according to waiting time: immediately or 7 days' delay. The six groups were then divided into three subgroups based on the adhesive procedure: Single Bond 2 (SB2), Clearfil SE Bond (CSB), and Clearfil Universal Bond (CUB). After adhesive procedures, composite resin cylinders were bonded to the enamel surfaces. All specimens were subjected to a SBS test after 24 hr of storage in water. Data were analysed using three-way variance analysis (p < .05). Specimens were examined under a stereomicroscope and SEM. There was a significant difference between the groups bonded immediately and 7 days after bleaching (p < .05). SB2 after 7 days showed the highest SBS values (19.24 ± 2.18), whereas CUB showed the lowest values in both bleaching treatments and control groups (10.84 ± 1.66). SEM analysis of the unbleached specimens revealed long tags and uniform hybrid layer compared OB and LW20 bleaching groups. LW20 and OB bleaching adversely affected SBS to enamel when bonded immediately. Diode laser-assisted bleaching might be an alternative option due to the short working time but delaying bonding for 7 days after bleaching may not be enough for ideal adhesion. RESEARCH HIGHLIGHTS: Bleaching agents containing high concentration hydrogen peroxide reduces the enamel bond strength of adhesive systems. Postponing composite restorations for 7 days after bleaching may not be sufficient to achieve ideal adhesion. Diode laser-assisted bleaching may be preferred as an alternative bleaching method today due to its ability to shorten the operation time and cause minimal morphological changes on the enamel surface.

Effect of warm-air stream for solvent evaporation on bond strength of adhesive systems: A systematic review and meta-analysis of in vitro studies

PurposeTo determine whether warm-air stream for solvent evaporation improves immediate and long-term bond strength of adhesive systems through a systematic review and meta-analysis. Materials and methodsPubMed, ISI Web of Science, Cochrane Library, SciELO, Scopus, and BVS, as well as Open Grey, were searched for relevant studies. Only in vitro studies reporting the effect of the use of warm-air stream to evaporate solvents of adhesive systems on the bond strength to enamel or dentin, were included. A global analysis compared the standardized mean difference between bond strength values using warm-air stream against a control group in which room-temperature air-stream was used. Bond strength from etch-and-rinse and self-etch adhesives was analyzed separately using the random-effects model at a significance level of α = 0.05. For each adhesive type, subgroup analyses were performed considering the type of solvent with which the adhesives were formulated. ResultsA total of 10 in vitro studies were included in the meta-analysis. For etch-and-rinse or self-etch adhesives, the use of warm-air stream for adhesive solvent evaporation improved the bond strength to dentin of water- or alcohol-based adhesive systems (p ≤ 0.03). On the contrary, this effect could not be observed for acetone-based adhesive systems (p ≥ 0.13). The overall effect demonstrated bond strength was enhanced with the use of warm-air stream (p ≤ 0.03). ConclusionThe in vitro evidence suggests that bond strength of self-etch or etch-and-rinse adhesives could be improved by using warm-air stream for solvent evaporation.

Etching time and bonding of adhesive systems to dentin of primary teeth: A systematic review and meta‐analysis

Due to the chemical and morphological differences between primary vs. permanent teeth, the time reduction of the acid etching or acidic primer can result in higher values of bond strength. To assess through a systematic review and meta-analysis the influence of the reducing etching (acid etching or acidic primer) time on the bond strength of adhesive systems to primary dentin. A systematic search was carried out in 3 databases: PubMed, Web of Science and Scopus. Studies that evaluated the effect of reducing the etching time on the bond strength of adhesive systems to primary dentin were included. Meta-analyses were performed using a random-effects model, with subgroups for etch-and-rinse and self-etching adhesives, with a significance level of P<.05. The risk of bias and heterogeneity between studies (Cochrane and I2 tests) were assessed. Eight studies were included in the systematic review and seven in the meta-analyses. The shortening etching time did not influence the immediate dentin bond strength for etch-and-rinse (Z=0.07, P=.95) and self-etching adhesives (Z=0.41, P=.69). After ageing, however, the shorting etching time improved the bond strength for etch-and-rinse adhesives (Z=2.01, P=.04). All studies presented high bias risk. Reducing the acid-etching time to primary dentin improves the long-term bond strength to this substrate.

Does previous application of silver diammine fluoride influence the bond strength of glass ionomer cement and adhesive systems to dentin? Systematic review and meta-analysis.

Silver diammine fluoride (SDF) applied before a restoration may prevent recurrent caries; therefore, its effect on the bonding of restorative materials is contradictory. To assess through a systematic review and meta-analysis the influence of SDF on the bonding performance of adhesive materials to dentine. A systematic search was carried out in PubMed, Web of Science, LILACS, and Scopus. Studies comparing bond strength of adhesive systems or glass ionomer cement to SDF-treated and -untreated (control) dentine were included. Global analysis comparing the bond strength data was performed, separately for adhesive systems and glass ionomer cement, using RevMan5.1, with a random-effect model, at a 5% significance level. Eleven studies were included in the review and ten in the meta-analyses. Overall pooled effect for glass ionomer cement has shown no significant difference between the groups (Z=0.47; P=.64). SDF treatment significantly impairs the bonding of adhesive systems to dentine (Z=2.11; P=.03); this effect can be eliminated by the rinsing step (Z=0.85; P=.40). The previous application of SDF does not influence the dentine bond strength of glass ionomer cement, but compromises the bonding of adhesive systems.

The efficacy of a bioglass (45S5) paste temporary filling used to remineralize enamel surfaces prior to bonding procedures

ObjectivesThe efficacy of using a 45S5 Bioglass paste as a remineralizing temporary filling material was compared to fluoride gel (1.23% acidulated-phosphate-fluoride, Gelato Gel, NJ, USA) applied for 24 h and for 4 min and to a temporary filling material (Caviton; GC, Tokyo, Japan). Methods66 extracted human premolars were used. All specimens were sectioned mesio-distally. All specimens were challenged by a demineralization solution (pH4.5) for 4 days. The specimens were divided into 4 groups: (Bioglass), (Fluoride 4­minutes), (Fluoride 24­Hours), and (Temp) (n = 33). 10 specimens were examined by TMR (Transversal Microradiography)to test remineralization capacity of each agent. 8 specimens were assigned to determine the acid resistance of a bonded resin-enamel interface after the various treatment methods. 15 samples were assigned to determine the effect of each agent on the shear bond strength of a single bottle self-etch adhesive system. One way ANOVA was used to compare the obtained results (p < 0.05). ResultsSpecimens treated with 45S5 bioglass showed statistically significant reductions in (delta z) values when compared to the other three groups (p < 0.05). Treatment of demineralized enamel by fluoride prior to bonding significantly decreased shear bond strength values, however 45S5 bioglass treatment did not affect the shear bond strength of adhesive system to enamel (p < 0.05). The acid-resistance of the interface between resin-enamel was significantly improved when fluoride or bioglass were applied onto the enamel surface prior to demineralization. Conclusions45S5 bioglass paste has high potential to be used as a remineralizing temporary filling material.

Effects of primer excess on marginal adaptation, nanoleakage and bond strength of adhesive systems after aging

There is no consensus about the amount of primer inserted into the cavity. Aim: This study aimed to evaluate the effects of the amount of primer used on dentin microtensile bond strength (µTBs), nanoleakage and marginal sealing, following thermomechanical aging. Methods: 48 human third molars were selected and a box-shaped class I cavity was constructed to maintain enamel margins. Teeth were randomly assigned to 6 experimental groups (n=8). For the bonding protocols of the restorative procedure, two adhesive systems were used: three-step etch-and-rinse and two-step self-etch. Epoxy resin replicas of the occlusal surface were made, and the specimens were submitted to thermomechanical aging. Newer replicas were obtained after thermomechanical aging, and marginal adaptation was observed using SEM. To obtain sections (0.7 x 0.7 mm) for testing at a tension of 0.5 mm/min, teeth were serially sectioned in the buccallingual direction, parallel to the occlusal surface. Failure mode was then obtained. For nanoleakage evaluation, one section of each tooth was immersed in AgNO3 and evaluated using SEM. The μTBs data were submitted to a two-way ANOVA and Tukey’s test (α= 0.05) Results: One drop of primer promoted higher µTBs than two or three drops. Besides, the three-step etch-and-rinse promoted greater μTBs (19.78) than the two-step self-etch adhesive (12.23). The increase in the amount of primer was directly proportional to the increase of infiltration. All groups exhibited more gaps after thermomechanical aging. Conclusion: Using an excess of primer is not recommended because it reduces the μTBs and forms an unsatisfactory hybrid layer.

An In Vitro Study of Effect of Beveling of Enamel on Microleakage and Shear Bond Strength of Adhesive Systems in Primary and Permanent Teeth.

ABSTRACTAim and objectivesThis in vitro study evaluated the effect of beveling of enamel on microleakage and shear bond strength of total-etch adhesive system: prime and bond NT and self-etch: adhesive system: XENO V in primary and permanent teeth.Materials and methodsA total of 120 extracted human molars (60 primary and 60 permanent) were selected for the study. For microleakage examination, a sample size of 40 was chosen. Two rectangular slots of equal dimensions were prepared on the buccal surface of each tooth and a bevel was given on either of the slots. Each slot was restored using a composite resin with prior application of the selected bonding agent following which all the samples were soaked in 1% methylene blue dye for 48 hours. Then each tooth was sectioned horizontally and evaluated. The remaining 80 samples were subjected to the shear bond strength test. Class II cavities of standard dimension were prepared and bevel was given on each sample following which selected bonding agent was applied and restored with a composite resin. The specimens were placed in a fixture and the shear bond strength was determined using the universal testing machine.ResultsWith respect to microleakage, the least was exhibited by beveled preparations in permanent teeth using the self-etch adhesive system and the highest shear bond strength was exhibited by beveled preparations using the total-etch adhesive system in permanent teeth.ConclusionBeveling of enamel improved the marginal integrity and shear bond strength of self-etch and total-etch adhesive systems in both primary and permanent teeth.How to cite this articlePatanjali S, Arora A, et al. An In Vitro Study of Effect of Beveling of Enamel on Microleakage and Shear Bond Strength of Adhesive Systems in Primary and Permanent Teeth. Int J Clin Pediatr Dent 2019;12(3):205–210.

Effect of hemostatic agent on microshear bond strength of total-etch and self-etch adhesive systems

Application of hemostatic agents can negatively affect the bond strength of adhesive systems to dental substrate. This study aimed to assess the effect of ferric sulfate on microshear bond strength of four total- and self-etch adhesives to dentin after water storage. In this in vitro study, 192 dentin slices with 2 mm thickness were made of 64 extracted sound human third molars. The samples were divided into 8 groups (n = 24) as follows: G1: Scotchbond Multi-Purpose, G2: hemostatic agent + Scotchbond, G3: Adper Single Bond, G4: hemostatic agent + Adper, G5: Clearfil SE Bond, G6: hemostatic agent + Clearfil, G7: Single Bond Universal, and G8: hemostatic agent + Single Bond Universal. Composite cylinders with 0.7 mm diameter and 1 mm height were bonded to the surfaces. Each group was then divided into two subgroups (n = 12) for water storage for 24 h and 3 months. The microshear bond strength was then measured. Data were analyzed using the Shapiro-Wilk test, three-way ANOVA, one-way ANOVA, and Tukey's test (P < 0.05). Application of ferric sulfate decreased the bond strength of all bonding agents after both 24 h and 3 months of storage; but, this reduction was not statistically significant (P > 0.05). Single Bond Universal at 24 h showed the highest and Adper Single Bond at 3 months showed the lowest bond strength (P < 0.001). Dentin contamination with hemostatic agents negatively affects the bond strength of total- and self-etch adhesives.

Tooth whitening affects bond strength of adhesive systems in enamel

This study presents how the tooth whitening affects the bond strength and fracture type of three distinct adhesives — a conventional, a self-etching, and a universal adhesive — in enamel. Health bovine incisors were prepared by flattening the labial surface; part of these teeth was submitted to whitening treatment with a peroxide-based product (WhiteGold Office© 35%). The Single Bond©, AdheSE©, or Single Bond Universal© adhesive system were used to adhere a block of restorative resin to the flat surface of the teeth. Sticks measuring 10x1x1 mm were prepared and used in microtensile tests; they were also employed to examine the type of fracture. The results are analyzed with a two-way ANOVA. For both whitened and non-whitened specimens, the adhesive systems did not give statistically different bond strength values. However, the fracture shape (classified into four types) varied from a cohesive enamel type fracture for the whitened samples to a predominantly cohesive resin type fracture for the non-whitened teeth. Therefore, the whitening procedure has exerted a weakening effect on enamel even after 21 days post-treatment. Keywords: Tooth whitening; adhesive systems; bond strength; fracture; restorative system.

Efficacy of multi-mode adhesive systems on dentin wettability and microtensile bond strength of resin composite

Purpose: To evaluate the wetting ability and the microtensile bond strength of adhesive systems in various depths of dentin. Materials and Method: 48 extracted human molars cut in half in buccolingual direction. Buccal and lingual surfaces were used to obtain deep (n = 48) and superficial (n = 48) dentin. Groups were divided into 4 subgroups: Self-etch (CSE), etch&rinse (SB), multi-mode self-etch (SAU) and multimode etch&rinse (EAU) adhesive systems. 3 consecutive contact-angle measurements were obtained: T0- 3 μl drop of distilled water on dentin; T1-Droplet of the adhesive; T2- Distilled water after polymerization of the adhesive. After composite build-ups, microtensile measurements were performed. Contact angle data were analysed with analysis of variance for repeated measures. Bond strength data were analyzed by repeated measures analysis of variance, comparisons were made according to the logarithmic values (p < 0.05). Results: The difference between groups was not significant regardless of dentin depth for all measurements (p < 0.05). All groups except CSE enhanced the wetting ability of the adhesive but reduced the wetting ability of distilled water after application of the adhesive (p < 0.05). Regarding adhesive systems, the groups showed no significant difference between bond strengths to various depths of dentin except SAU (p > 0.05); in SAU, bond strength to deep dentine were significantly higher than superficial dentin (p < 0.05). Regarding adhesives’ bond strength, CSE showed significantly greater values than the other groups (p < 0.05). Conclusion: The cavity depth does not affect the bonding ability for all adhesive systems; self-etch adhesive systems might be a better choice since different adhesives may influence the wetting ability and microtensile bond strength of the dentin substrates.

Zinc oxide eugenol paste jeopardises the adhesive bonding to primary dentine.

This was to evaluate the influence of root canal filling pastes on microshear bond strength (µSBS) of an adhesive system to primary dentine. Human (32) primary molars were randomly assigned into four experimental groups (n = 8): zinc oxide eugenol paste (ZOE); iodoform paste (Guedes-Pinto paste); calcium hydroxide paste thickened with zinc oxide; and no filling paste (control). Flat dentine surfaces were covered with a 1mm-thick layer of the pastes for 15min at 37°C. The pastes were mechanically removed from dentine surfaces, followed by rinsing and drying. After adhesive application (Adper Single Bond 2, 3M ESPE), starch tubes were placed over pre-treated dentine and filled with composite resin (Z250, 3M ESPE). The µSBS test was performed after 24h of water storage at 37°C. The failure mode was evaluated using a stereomicroscope. The µSBS values (MPa) were analysed with one-way ANOVA and Tukey post-hoc tests (α = 0.05). The lowest µSBS values were achieved when ZOE was used. No difference was found among other filling pastes compared with control group. All specimens showed adhesive/mixed failures. Zinc oxide eugenol paste negatively influenced the bond strength of adhesive systems to primary dentine. Iodoform-based Guedes-Pinto paste and calcium hydroxide paste thickened with zinc oxide did not influence the microshear bond strength values.

The effect of endodontic irrigants on the microtensile bond strength of different dentin adhesives.

The aim of this study was to determine the influence of irrigants on bond strength of adhesive systems. Superficial dentin surfaces of 60 extracted molars were divided into 15 groups, according to irrigants and adhesives. In the control groups, surfaces were irrigated with distilled water. In experimental groups, sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA) + NaOCl, chlorhexidine (CHX), and NaOCl + sodium ascorbate were used as irrigants. Resin composites were then built up using Single Bond, Clearfil SE Bond, and Xeno 3 as adhesives. The microtensile bond strength of groups was determined. Data were statistically analyzed by two-way analysis of variance (ANOVA), one-way ANOVA, and the Bonferroni test. NaOCl reduced bond strength of Single Bond and Clearfil SE Bond (P < 0.01). For all adhesive systems, EDTA + NaOCl-treated groups exhibited lower bond strength than control groups (P < 0.01). CHX decreased bond strength of Single Bond (P < 0.01). Application of sodium ascorbate improved compromised bond strength to NaOCl-treated dentin (P < 0.01). Different irrigants had several effects on bonding of different adhesives. Sodium ascorbate after NaOCl could restore compromised bond strengths.

Effect of cleaning protocols on bond strength of etch-and-rinse adhesive system to dentin

Aim:This study aimed to evaluate the cleaning protocol of dentin impregnated with epoxy resin-based sealer (AH Plus) and the effects on the adhesive interface using 95% ethanol (E) or formamide solution (F) associated with microabrasion with glass microparticles (M).Methodology:Forty dentin specimens were impregnated with sealer (AH Plus). Specimens were cleansed according to the following protocols (n = 10): G1 (E); G2 (F); G3 (E = M); and G4 (F = M). No treatment was performed in G5 (control). Specimens were subjected to standard error of the mean to evaluate the residues persistence (×500) and open dentinal tubules counting (×2000). Another fifty specimens were subjected to similar procedures and cleaning protocols. Seven days later, composite-resin-made specimens were performed on dentin using etch-and-rinse adhesive system, then submitted to microshear test.Results:G2 and G4 showed higher residues' persistence and lower incidence of open dentinal tubules than G1 and G3 (P < 0.05). No difference was found between G1 and G3 or G2 and G4 (P > 0.05). Adhesive system bond strength was similar in all groups (P > 0.05).Conclusions:Microabrasion negatively affected the epoxy resin-based sealer residues' removal protocols' action; all groups presented residues on the dentin surface. However, 7 days later, the protocols did not affect the bond strength of adhesive system to sealer-impregnated dentin.