Dentin Adhesive Systems Research Articles

Do in vitro and in situ erosive challenges alter the bonding performance of universal adhesives?

ObjectiveTo evaluate microtensile bond strengths (μTBS), nanoleakage (NL), and degree of conversion (DC) of two universal adhesives, using etch-and-rinse (ER) or self-etch (SE) strategies on eroded dentin submitted to in vitro and in situ erosive challenges. MethodsDentin blocks were prepared from 120 human molars and categorized based on dentin condition (sound, in vitro eroded, and in situ eroded), adhesive system (Scotchbond Universal [SBU] and Zip bond Universal [ZIP]), and adhesive strategy (ER and SE). In the in situ erosive challenge, 20 volunteers wore acrylic resin palatal devices with dentin blocks, immersing them in cola soft drink for 90 s, six times daily for 15 days. The same erosive protocol was used in vitro, followed by rinsing and remineralization. Sound dentin blocks served as controls. Afterward, all dentin blocks were restored with composite resin and sectioned into resin-dentin bonded sticks for μTBS, NL, and DC assessments. Data were analyzed using three-way ANOVA and Tukey's test (α = 0.05). ResultsSound dentin exhibited the highest μTBS and DC values and the lowest NL values, while in situ eroded dentin showed the lowest μTBS and DC values and the highest NL values (p = 0.000001). While some differences in the μTBS values were observed between universal adhesives when evaluated on sound dentin (p = 0.0001), no significant differences between adhesives were observed when tested on in vitro and in situ eroded dentin. Regarding NL and DC, no significant differences were found between SBU and ZIP, as well as among adhesive strategies (p > 0.05). ConclusionErosion in dentin, especially under in situ conditions, presents significant challenges to the adhesion of restorative materials. The choice of an effective adhesive system is crucial, as dentin eroded in situ showed lower adhesion strength and greater nanoleakage. These results highlight the need for specific clinical strategies to improve the durability and effectiveness of restorations.

Effects of Riboflavin Collagen Crosslinker on Dentin Adhesive Bonding Efficiency: A Systematic Review and Meta-Analysis.

The aim of this study was to evaluate published data regarding riboflavin (RF) as a cross-linker for improved adhesive bond strength to dentin and to analyze previous studies for optimal concentration of riboflavin range suitable for dentin bond. Saliva and distilled water were used as storage media and aging time was 24 h and 6 months. Results of meta-analysis were synthesized using a statistical method of inverse variance in random effects with a 95% Confidence Interval (CI). Cochrane review manager 5.4.1 was used to determine results of the meta-analysis. In total, 3172 articles were found from search databases "PubMed", "Scopus", and "Google Scholar". Six of the fifteen studies were eligible for meta-analysis. Micro tensile strength shows significant improvement with the addition of riboflavin (p < 0.05) compared to without the addition of riboflavin from with 95% CI. A significant difference has been found in micro tensile bond strength between use of the riboflavin cross-linker and without use of the riboflavin crosslinker in the dentin adhesive system. With a 95% confidence interval (CI), the I2 for micro tensile strength was 89% with strong heterogeneity, Chi2 = 44.76, df = 5 (p < 0.00001), and overall effect size is Z = 2.22 (p = 0.03) after immediate aging. Chiang et al. 2013 shows maximum mean differences which is 38.50 [17.93-59.07]. After 6 months of aging in distilled water or artificial saliva micro tensile bond strength has been increased with the addition of riboflavin (p < 0.05). It can be clearly seen that pooled effect and 95% CI did not cross the line of no effect. With a 95% confidence interval (CI), the I2 for micro tensile strength was 96% with strong heterogeneity, Chi2 = 117.56, df = 5 (p < 0.00001), and overall effect size is Z = 2.30 (p = 0.02). Subgroup analysis proved a similar effect of distilled water and artificial saliva as storage media on micro tensile bond strength after incorporating riboflavin as a collagen crosslinker. An artificial saliva aged forest plot also showed considerable heterogeneity with I2 = 96%; Tau2 = 257.32; Chi2 = 94.37; df = 2 (p < 0.00001); test for overall effect, Z = 1.06 (p = 0.29). Riboflavin prior to or with bonding is recommended to improve the bonding of different adhesive systems.

Effect of dentin moisture on the adhesive properties of luting fiber posts using adhesive strategies.

The purpose of this study was to evaluate the effect of dentin moisture (moist and dry) on the bonding of fiber posts to root dentin with different adhesive strategies (etch-and-rinse, self-etch, and self-adhesive). Seventy-two extracted single-rooted human teeth were endodontically treated and divided into six groups (n = 12) according to the moisture of dentin surface and adhesive systems as follows: a) etch-and-rinse/moist, b) etch-and-rinse/dry, c) self-etch/moist, d) self-etch/dry, e) self-adhesive/moist, and 6) self-adhesive/dry. The specimens were sectioned into six slices for push-out bond strength (BS), nanoleakage (NL) by SEM, and Vickers microhardness (VHN) of the resin cement. A universal testing machine (AG-I, Shimadzu Autograph) was used at a crosshead speed of 0.5 mm/min until post extrusion, with a load cell of 50 kg for evaluation of the push-out strength. Data on BS, NL, and VHN were evaluated by two-way ANOVA and Tukey's test (α = 0.05). Dentin moisture as the main factor was not significantly different for the push-out test. However, higher BS values can be observed for the etch-and-rinse group. A lower percentage of NL was found in the dry dentin groups. The moisture pattern was not significant in the hardness values for the pre-etching groups. Additional moisture did not increase the evaluated properties.

&lt;i&gt;In vitro&lt;/i&gt; study on non-thermal argon plasma in improving the bonding efficacy between dentin and self-etch adhesive systems

Self-etch adhesive systems have the advantages of simple operating steps and low technique sensitivity. However, some deficiencies of self-etch adhesive result that the immediate bonding strength between self-etch adhesive and dentine is not so high. Non-thermal atmospheric pressure plasma (NTAPP) can be used for surface modification. Previous studies of our research group have proven that NTAPP can improve bonding durability between dentine and etch-and-rinse adhesive. However, it is still unknown whether NTAPP can improve bonding strength between dentine and self-etch adhesive. The study observed the contact angle on dentine surface, the adhesive permeability and MTBS. The study proved that NTAPP can improve dentine surface wettability, clear up smear layer, and enhanced the self-etch adhesive permeability in dentine bonding interface. In conclusion, NTAPP could improve the bonding strength between dentine and self-etch adhesive systems. The most optimum treating time was 15 s.

Polyphenol-Enriched Extract of Lacquer Sap Used as a Dentine Primer with Benefits of Improving Collagen Cross-Linking and Antibacterial Functions.

Commercial dentin adhesive systems are applied to restorations due to their resistant bonding properties, but they suffer from the lack of bioactivity and are prone to hydrolysis. Therefore, to overcome these limitations, an eco-friendly natural monomer, urushiol, was adopted to be a primer in dentin bonding due to its interaction with collagen and antibacterial activity, preventing further hydrolysis development. First, urushiol was determined to be capable of improving the biological stability of dentin collagen through cross-linking. Using high-fidelity analytical chemistry techniques, such as Fourier transform infrared spectroscopy, we quantified the effects of urushiol on collagen molecules. It could also effectively decrease weight loss after collagenase ingestion by improving the stability of dentin. Moreover, urushiol inhibited Streptococcus mutans growth as well as its biofilm formation. Finally, we demonstrated that the urushiol primer could improve the bonding strength, particularly after aging. The cross-linking and antibacterial functions of urushiol have provided promising developmental prospects for biomaterials in dentin adhesion.

Bonding of Fractured Fragments using Various Bonding Materials as a Treatment Modality in Cases of Vertical Root Fracture- A Systematic Review

Introduction: Vertical Root Fracture (VRF) is third most common factor leading to extraction of root canal treated tooth. It has a longitudinal orientation. This occurs due to reduction in structural integrity and dehydration of dentine. Most common treatment includes extraction of the teeth. Other modality is amputation of involved root in molars. Various materials can also be used for bonding of the fragments. Aim: To compare and evaluate the effectiveness of dentine bonding systems in re-attatchment of fractured root. Materials and Methods: The present systematic review included a comprehensive search of last 10 years was performed in the systematic electronic database PubMed. In-vitro laboratory studies that evaluated the microtensile bond strength and fracture resistance of multiple dentine adhesive systems and compared them in human and/or animal teeth in which VRF had occurred were included. A total of 16 non duplicated studies were retrieved in the systematic search. Results: Out of 16 studies four studies were included in the systematic review. One study assessed the bond strength of the adhesive using table top testing machine. Two studies assessed the microtensile bond strength using stereo microscope and one study assessed recurrence of the fracture using Instron Machine. The studies demonstrated large variability among methodology used for evaluation. In one study, acid phosphate monomer showed highest microtensile bond strength (p&lt;0.05), and in another study Refracture (RF) occurred easily in samples bonded with Glass Ionomer Cement (GIC) as compared to those bound with Perma Bond and Gluma (p&lt;0.0003). Conclusion: From the present study's analysis, dual cure adhesive resin cement either reinforced with polyethylene fibers or glass fibers, and glass ionomer cement may increase the fracture resistance of bonded tooth.

The Influence of Desensitizing Agent on Shear Bond Strength of Dentin Using Two Dentin Adhesive Systems

This is in vitro study evaluate the effect of desensitizing agent on shear bond strength of two different adhesive systems scotch bond (water/ethanol/base adhesive system) and prim and bond NT (acetone base adhesive system). fouty-two human upper &amp; lower premolar teeth recently extracted for orthodontic purpose were selected. These teeth polished and cleaned before embedded in acrylic block. 2mm from the buccal surface of the blocked tooth were ground to obtain flat surface with 600 grit silicon carbide paper. Each tested groups has been treated with desensitizing agent for 2 minutes and leave it without washing for 10 minutes. The tested and control groups were etched using 37% of the phosphoric acid, and the bonding system was applied according to manufacture instruction. The specimens were divided in two main groups. Each one subdivided in two subgroups: Group A: Treated with scotch bond 1 with 3m feltick Z 250 composite resin.Subgroup A1¬: (control group).Subgroup A¬2: (tested group, dentin surface pretreated with desensitizing agent before etching).Group B: treated with prim&amp; bond NT adhesive system with feltick Z 250.Subgroup B1: (control group).Subgroup B2: (tested group, dentin surface pretreated with desensitizing agent before etching). Shear bond strength was determined using instron testing machine and result showed that.•There is a significant decrease in shear bond strength for scotch bond -1 adhesive system and 3m feltick Z 250, after with desensitizing agent (soothe) for 2minutes.•There is no significant difference in the shear bond strength after treatment the prepared surface of dentin with desensitizing agent (soothe) for 2minutes.•The effect of desensitizing agent is depend on the type of bonding system were used.Aims of the study The aim of this study in vitro study is to evaluate the effect of desensitizing agent on shear bond strength of:1.scotch bond 1 adhesive system with 3m feltick Z 250 composite resin.2.prim &amp; bond NT adhesive system with 3m feltick Z 250 composite resin.

Influence of Low-Level Laser Modification and Adhesive Application Mode on the Bonding Efficiency of Universal Adhesives to Er:YAG Laser-Ablated Dentin.

Introduction: Erbium laser ablation as a method of tooth preparation and conditioning has shown promising results. Although previous studies have adopted various combinations of different laser parameters and several dentin adhesive systems, very few have investigated combining high-level and low-level ER:YAG lasers with Universal adhesives. This study aimed to assess the impact of using low-energy irradiation on the surface micro-topography and shear bond strength (SBS) of universal adhesive (UA) to the erbium:yttrium-aluminum-garnet (Er:YAG) laser-ablated dentin substrate, bonded in etch-and-rinse or self-etch adhesive mode. Methods: Eighty-seven extracted molars were sectioned to expose flat occlusal dentin surface; 60 teeth were divided equally into three groups according to the surface treatment; bur-cutting (B), Er:YAG high-energy laser cutting (L1 - 200 mJ, 20 Hz, 50 μs pulse), or L1 followed by low-energy laser modification (L1 /L2 - 80 mJ, 10 Hz, 50 μs pulse). Then each group was equally divided into two groups (n=10) according to the mode of application of the universal adhesive; either etch-and-rinse (ER) or self-etching (SE). The samples were subjected to thermocycling (5000 cycle between 5°C and 55°C), and SBS was tested. Two-way ANOVA and Tukey post hoc test were used to analyze the results. The remaining 27 samples were used to investigate the effect of the treatment on the topography of the treated dentin surfaces using a scanning electron microscope (SEM). Results: B/SE recorded the highest SBS (25.48 ± 2.6 MPa) followed by B/ER (23.20 ± 6.8 MPa) and L1 /L2 /SE (22.94 ± 4.1 MPa) and with no statistically significant difference between these groups (P >0.05). The lowest SBS results (P <0.05) were recorded for L1/SE (12.22 ± 3 MPa). No statistical differences were found between the SBS of L1 /L2 /ER and L1 /ER groups or between the SBS of L1 /L2 / ER and L1 /L2 /SE groups. Conclusion: A subsequent treatment of the Er:YAG laser-ablated dentin with low-energy laser modification mode (LMM) enhances the SBS of the tested UA when applied in SE mode.

Comparative evaluation of shear bond strength of a dual-cure core build-up composite bonded to dentin using three different self-etch dentin bonding systems - An in-vitro study

Aim: This in-vitro study compared the shear bond strength of a dual-cure core build-up composite bonded to dentin using a two-step self-etch adhesive, with two, single step self-etch universal adhesive systems. Materials and Methods: In the present in-vitro study, sixty extracted permanent human mandibular molar teeth, decoronated below the dentino-enamel junction to expose the coronal dentin, were taken and later mounted in self-cure acrylic resin. The specimens were randomly divided into three groups of twenty samples each, based on the dentin bonding agents used namely ParaBond (a two-step self-etch adhesive) and two one-step universal adhesives i.e. Single Bond Universal and Tetric N-Bond Universal. The dentin surface of samples was treated with the respective adhesives of the groups according to manufacturer’s instructions. The bonded surface was bulk filled using ParaCore dual-cure composite. The attained samples were stored in distilled water at 370C for 24hrs and subsequently put through thermocycling (50C to 550C for 500 cycles). The samples were than subjected to shear loading in Instron Universal testing machine. The data were tabulated and statistically analyzed using analysis of variance (ANOVA) and Tukey’s HSD test. Results: Tetric N-Bond Universal adhesive showed the highest mean Shear Bond Strength (SBS) of 20.78 MPa, followed by Single Bond Universal 19.07 MPa and ParaBond Adhesive 5.44 MPa. Conclusion: Tetric N-Bond Universal showed the highest mean SBS and a predictable relationship was found between the formulation of dentin adhesive systems and their shear bond strength values. Clinical Significance: The universal adhesives showed high shear bond strength as compared to conventional 2-step self-etch adhesives. High acidic pH of self-etch adhesive affected their bond strength. So for stake of bond stability, a mild self-etch / universal adhesive is recommended for adhesion, because higher the bond strength, higher it can withstand the stress

Effect of polydopamine incorporated dentin adhesives on bond durability

Inspired by mussel-adhesion phenomenon in wet environment, polydopamine (PDA) was tried in recent research reports to improve the dentin adhesive interface with better strength and durability. The aim of this study was to comparatively evaluate the effect of PDA incorporated dentin adhesive systems and conventional adhesive systems on degree of conversion (DC), resin dentin bond strength (SBS), durability and MMP inhibition activity. In this study, PDA was incorporated in total-etch adhesive system (TE) and self-etch adhesive systems (SE) and degree of conversion (DC%) was evaluated using Fourier transform infrared spectroscopy. Dentin slabs obtained from 160 non-carious human premolars were divided into the following: Group 1, TE; Group 2, PDA incorporated TE adhesive (TEP); Group 3, SE; Group 4, PDA incorporated SE adhesive (SEP) and bonding procedures were performed. Samples were stored for either 24 h or 6 months, after which shear bond strength and resin dentin interface was evaluated using universal testing machine and confocal laser scanning microscopy (CLSM), respectively. The zymographic assay was performed on protein extracts obtained from dentin powder treated with each of the adhesives or with or without PDA followed by functional activity assay for MMP-2 and -9. Statistical analysis was done with two-way analysis of variance and Student t-test at significance level as p < 0.05. There was statistically no significant difference in the DC% between PDA incorporated adhesives and control. No significant reduction in SBS was observed in TEP and SEP in pre- and post-aging while CLSM showed better penetration depth of resin and lesser degradation of hybrid layer on aging. Significantly lesser MMP activity was seen in PDA incorporated adhesives qualitatively and quantitatively on zymographic and functional MMP activity assay respectively. HIGHLIGHTS Catechol moieties present in polydopamine provide anti-collagenolytic activity, MMP inhibitory activity and enhances wet adhesion. Polydopamine incorporated dentin bonding systems attempts to provide stable resin dentin bond with increased bond durability. It can inhibit both proteolytic and hydrolytic breakdown of resin–dentin bond degradation.

The microtensile bond strength test: Its historical background and application to bond testing.

SummaryMicrotensile bond strength (μTBS) test was introduced in 1994. Since then, it has been utilized profoundly across many bond strength testing laboratories, making it currently one of the most standard and versatile bond strength test. Although it is a static and strength-based method, together with the morphological and spectroscopic investigations, it has been contributing immensely in the advancement of dentin adhesive systems. μTBS test has a greater discriminative capability than the traditional macro-shear bond test. During the early stage of its development, the authors predicted that this testing method would enable evaluation of the adhesive performances of resins to excavated carious or sclerotic dentin and the regional bond strengths of various portions of the cavity. In addition, they also stated the possibility of comparing the long-term stability of resin adhesion at various portions of the cavity walls on teeth extracted at various times after insertion of bonded restorations. In this review, we discussed the historical background, inception and the application of the μTBS test and proposed directions for further improvement of this testing method.

Effects of sodium hypochlorite as dentin deproteinizing agent and aging media on bond strength of two conventional adhesives.

This study evaluated the effect of 10% sodium hypochlorite (NaOCl) as deproteinizing agent and storage media on bond strength (BS) of two etch-and-rinse adhesive systems to dentin. Twenty-eight sound extracted human third molars were divided in four groups (n = 7), according to dentin treatment (conventional etching or etching followed by 10% NaOCl application) and adhesive systems (GB-Gluma 2Bond and OS-One-Step). After dentin treatments and adhesive application, a composite block was built-up on dentin surface and teeth were serially sectioned to obtain bonded sticks specimens. The sticks were submitted to three aging conditions: (24H) 24 hr in water (immediate), (SH) 3 hr of NaOCl accelerated-aging or (1Y) 1 year of water storage. Afterward, submitted to microtensile bond strength test (μTBS), failure modes and adhesive interfaces analyzes. Data were analyzed by two-way analysis of variance (ANOVA) and Tukey's test (α = .05). Dentin deproteinization before bonding significantly reduced μTBS for GB-treated group (p < .05), regardless the aging conditions. Water storage for 1 year (1Y) and NaOCl accelerated-aging (SH) decreased μTBS for both adhesives. Yet, the groups stored in NaOCl (SH) exhibited the lowest BS results (p < .05). Bond strength of deproteinized dentin was dependent on the adhesive system composition and NaOCl accelerated-aging promoted decreased bond strength and further degradation than water storage for 1 year.

Effects of Er,Cr:Ysgg Laser on Microleakage of a Self-Etch Adhesive System

Objectives: The purpose of this in-vitro study was to evaluate the microleakage of a self-etch dentin adhesive system in cavities prepared by a conventional dental bur and an Er,Cr:YSGG laser.Materials and Methods: Forty extracted premolar teeth were selected randomly. Standardized Class V cavity preparations were placed in the buccal and lingual surfaces using a bur and an Er,Cr:YSGG laser. Eighty preparations were randomly assigned to 4 groups of 20 samples each and restored as follows: (G1, Control group) Bur; (G2) Bur + Laser etch; (G3) Er,Cr:YSGG laser; (G4) Er,Cr:YSGG laser + Laser etch. The cavities were restored with a self-etch adhesive system (GC, Unifil Bond) and composite resin (GC, Gradia). The preparations were sectioned buccolingually into three parts and scored for microleakage using a light stereoscope. The data were analyzed with Mann-Whitney U test, and Chi-squared test was used for comparisons across groups. Results: In all groups, there was higher microleakage in the gingival margin than in the occlusal margin. In the control group (G1), the lowest microleakage values were obtained in all the cavities. In comparison among the groups, statistically significant microleakage values were obtained in the occlusal margins. Significantly high microleakage was observed in G4 in comparison to G1 and G3 (p = 0.001, p = 0.003). Conclusions: Preparation and etching by using an Er,Cr:YSGG laser does not decrease microleakage, but this may also be due to the properties of the self-etch adhesive. Further clinical research and long-term follow-ups are needed to analyze the findings in more detail.

Randomized clinical trial of four adhesion strategies: A 42 month study.

The adhesives clinical effectiveness has been extensively reported for noncarious cervical lesions (NCCLs). However, there is a lack of information about the adhesive systems strategies and their effect on NCCL restoration longevity. This study aims to evaluate a 42-month performance of four dentin adhesive systems used for the restorative treatment of NCCLs. NCCLs were randomly divided into four groups: (1) Scotchbond multi-purpose (MP); 2: Single bond plus (SB); 3: Scotchbond SE (SE); and 4: Easy bond (EB). NCCLs (125) were randomly distributed: (1) MP; (2) SB; (3) SE; and (4) EB and were restored with a nanofilled resin-composite, evaluated along 18-36-42 months. Kruskal-Wallis test: Comparison among the adhesive systems in each period. Friedman analysis: Comparison along the periods. Kaplan-Meier: Survival analysis. Baseline and 42-month retention (RET) rates (%) were 100/100 for MP; 100/94.74 for SB; 100/87.5 for SE; and 100/100 for EB. The cumulative failure percentage was 9.52% for MP, 9.52% SB, 15.8% SE, and 10% EB. Restorations survival was not dependent on the used adhesive type. Marginal adaptation (MA) was similar to each group, but EB presented noticeable marginal deterioration. Wear was noticed in the 3-step etch-and-rinse (MP) restorations evaluated after 42 months. For the EB, baseline and 18-month wear evaluation were statistically similar. After 36 and 42 months, wear was also similar for EB. Adhesive systems showed similar performance within most important adhesive bonding efficiency achievement parameters: RET, MA, interfacial staining, recurrent caries, and postoperative sensitivity evaluated during 42 months.

Effect of Papain and Bromelain Enzymes on Shear Bond Strength of Composite to Superficial Dentin in Different Adhesive Systems

The aim of this study was to compare different dentin treatments and adhesive systems on shear bond strength (SBS) of composite to superficial dentin. In this in vitro experimental study, 60 extracted human upper premolars were cut 0.5 mm deep under occlusal DEJ and were randomly divided into six groups (n = 10) based on the method of dentin treatment and adhesive system: (A) two steps self-etch adhesive system (Clearfil SE bond) and (B) two steps of total etch bonding system (Adper single bond 2). (C) 10% papain + Clearfil SE bond. (D) 10% papain + Adper single bond 2. (E) 6% bromelain + Clearfil SE bond. (F) 6% bromelain + Adper single bond 2. Then, a plastic mold was placed on dentin and filled with resin composite. Shear bond strength (MPa) was tested by a universal testing machine (Zwick/Roell Z020, Germany), and the data were statistically analyzed by two-way ANOVA and Tukey's test (p < 0.05) and were applied for mean comparison. A significant difference was detected in the SBS evaluation between the applied adhesive systems (p = 0.0007). The SBS was also significantly affected by the interaction of treatment and etching techniques (p = 0.028). The group with 10% papain as a deproteinizing agent before the self-etching adhesive system showed the highest SBS (p = 0.029). There were no significant differences considering the specimens exposed to papain before the total etch adhesive system (p = 0.13), and the specimens were exposed to bromelain enzyme before self-etch and total etch adhesive systems (p = 0.25, p = 0.84, respectively). Papain enzyme treatment with the self-etch adhesive system increased the SBS value. Additionally, the application of bromelain enzyme as dentin treatment before two adhesive systems and papain before total etch adhesive system had no effect on the SBS of composite to superficial dentin. Application of adhesive systems and dentin treatment can influence the bond strength.

Bond strength assessment of a universal adhesive system in etch-and-rinse and self-etch modes

Abstract Introduction Modern dentistry is reflected in the insertion of new materials with different adhesion forms in dental structures, such as the Universal adhesive system. Objective To evaluate the bond strength of the universal dentin adhesive system, in the form of self-etching and conventional application, compared with a simplified conventional adhesive system, in two distinct periods: 1 week and 6 months. Material and method 48 bovine incisors separated into 6 groups, stored for 7 days, were selected. Worn out the buccal enamel until dentin exposure. Adper Single Bond 2 (3M Espe) or SingleBond Universal (3M Espe) adhesives were applied, and catheters filled with Opallis Flow (FGM) composite were placed. After photoactivation, the catheters were removed and the specimens (n = 48), stored in distilled water at 37 °C for one week and six months, were exposed. The specimens were fixed to a universal testing machine (EMIC DL 2000) with a speed of 0.5 mm / min. Bond strength (BS) was calculated in MPa, and data were statistically analyzed by Anova and Tukey test at 5% significance level. Result For Adper Single bond, the BS was equivalent in the times tested; for Universal conventional and self-conditioning time influenced the BS, with a decrease in the results. At 1 week, all stickers were different from each other, with higher BS for Universal conventional mode, followed by universal self-etching mode and then Adper Single bond. Conclusion The best results were achieved with universal adhesive in conventional mode for both tested times.

Structure-property relationships for wet dentin adhesive polymers.

Dentin adhesive systems for composite tooth restorations are composed of hydrophilic/hydrophobic monomers, solvents, and photoinitiators. The adhesives undergo phase separation and concomitant compositional change during their application in the wet oral environment; phase separation compromises the quality of the hybrid layer in the adhesive/dentin interface. In this work, the adhesive composition in the hybrid layer can be represented using the phase boundaries of a ternary phase diagram for the hydrophobic monomer/hydrophilic monomer/water system. The polymer phases, previously unaccounted for, play an important role in determining the mechanical behavior of the bulk adhesive, and the chemomechanical properties of the phases are intimately related to the effects produced by differences in the hydrophobic-hydrophilic composition. As the composition of the polymer phases varies from hydrophobic-rich to hydrophilic-rich, the amount of the adsorbed water and the nature of polymer-water interaction vary nonlinearly and strongly correlate with the change in elastic moduli under wet conditions. The failure strain, loss modulus, and glass transition temperature vary nonmonotonically with composition and are explained based upon primary and secondary transitions observed in dynamic mechanical testing. Due to the variability in composition, the assignment of mechanical properties and the choice of suitable constitutive models for polymer phases in the hybrid layer are not straightforward. This work investigates the relationship between composition and chemomechanical properties of the polymer phases formed on the water-adhesive phase boundary using quasistatic and dynamic mechanical testing, mass transfer experiments, and vibrational spectroscopy.

Bond strength of adhesive systems to sound and demineralized dentin treated with bioactive glass ceramic suspension.

The objective of this study was to evaluate the effect of a Biosilicate®, associated with dentin adhesive system, on microtensile bond strength (μTBS) to sound and demineralized dentin. Eighty sound-extracted molars had their middle occlusal dentin exposed. In forty teeth, dentin was artificially demineralized (pH cycling). Sound and demineralized dentin teeth were separated into four groups (n = 10), according to the substrate treatment before restoration: Group 1-total-etching adhesive Adper TM Single bond 2 (ASB) + Biosilicate®, Group 2-ASB (without Biosilicate®), Group 3-AdheSE self-etching adhesive system (AdSE) + Biosilicate®, and Group 4-AdSE (without Biosilicate®). Each tooth was restored with a hybrid composite and stored in water at 37°C for 6months. After water aging, teeth were cut in sticks (≈1mm2 cross-sectional area) and all samples were submitted to μTBS test. The fracture modes of the samples were analyzed by stereomicroscopy. The representatively fractured samples were observed by scanning electron microscopy. Representative samples of each group were analyzed on energy dispersive X-ray spectrometry (EDX). The μTBS and Ca-P ratio values were analyzed by 2-way ANOVA, Bonferroni, and Tukey test, respectively, p < .05. ASB + Biosilicate® presented the highest μTBS values (p < .05), and lowest μTBS values (p < .05) were found in AdSE Group. There was no statistical difference (p < .05) on μTBS when substrates were compared, except for Group 2. The fracture pattern analysis showed prevalence of adhesive fractures in all groups. Biosilicate® enhanced bond strength of self-etching and etch-and-rinse adhesives to sound and demineralized dentin. Bioactive glass ceramic suspension could be recommended to be used to improve the dentin bond strengths of the total-etching and self-etching adhesives after acid-etching and priming.

The micromorphological characterization of adhesive bond in dentin different locations

The aim of this study was to analyse the interfacial micromorphology of total-etch adhesives and dentin structures different locations by using SEM. Standardized cylindrical cavities (3mm in diameter, 2mm deep) with all margins in dentin were prepared on occlusal and buccal surfaces of twenty extracted human third molars. A total-etch dentin adhesive system and a light-cure flowable composite (Filtek Ultimate Flowable, 3M ESPE, St. Paul, MN, USA) were used in this study. Micro-morphological SEM analysis of the marginal seal of the original tooth specimens was performed using high magnification of up to 1000×. In this study, we found the difference in interfacial micromorphology in dentin different locations. Also, marginal gap was found in both observed dentin area. Better understanding of complexity and three- dimensional variations of the tooth structure is important for prevention of clinical challenges such as postoperative sensitivity, marginal discoloration and secondary caries, which could be prevented by achieving of predictable and long-lasting adhesive bond.

Susceptibility of contemporary single-bottle self-etch dentine adhesives to intrinsic water permeation

ObjectivesTo evaluate the effect of intrinsic water permeation on the microtensile bond strengths of different adhesive systems to dentine and the quality of resin-dentine interfaces. MethodsNinety-six non-carious human third molars were divided into 4 groups: Clearfil S3 Bond Plus (CSBP; Kuraray); Clearfil S3 Bond (C3S; Kuraray); iBond Self-Etch (IB; Heraeus-Kulzer) and Prime&Bond NT (PB, control etch-and-rinse adhesive, Dentply-Sirona). For each adhesive, specimens from one subgroup (N=10) were bonded using zero pulpal pressure, while specimens from the other subgroup (N=10) were bonded using 15cm water pressure (PP). Each bonded tooth was sectioned into 1×1mm sticks and stressed to failure. Data were analysed using two-way ANOVA and Holm-Sidak pairwise comparisons to examine the effects of “adhesive”, “pulpal pressure” and their interaction on bond strength (α=0.05). Representative fractured sticks were examined by SEM. The remaining tooth slabs in each subgroup were used for TEM and CLSM. ResultsMicrotensile bond strengths (mean±SD; in MPa) were: 33.4±6.9 (CSBP), 33.2±4.7 (CSBP-PP), 35.0±8.6 (C3S), 25.5±7.3 (C3S-PP), 18.4±4.0 (IB), 16.5±6.9 (IB-PP), 28.2±5.5 (PB), 20.5±7.2 (PB-PP). “Adhesive-type” (P<0.001), “pulpal-pressure” (P<0.001) and their interactions (P<0.001) significantly affected bond strength results. No difference between no-PP and PP subgroups was found for CSBP and IB (P>0.05). Water droplets were identified along the resin-dentine interface for IB, IB-PP and C3S-PP. ConclusionIB exhibits water sensitivity when bonding is performed with/without pulpal pressure. C3S exhibits water sensitivity when bonding is performed with pulpal pressure. CSBP does not exhibit water sensitivity when bonding is performed with/without pulpal pressure.Clinical significance: Intrinsic water permeation during bonding procedures significantly affects bond strength results and the resin-dentine interface of contemporary single-bottle self-etch dentine adhesive systems.