Comparison of microleakage of a multi-mode adhesive system with contemporary adhesives in class II resin restorations

Aim: The aim was to compare the microleakage of resin composite bonded with different adhesive systems in class-II cavities at enamel or dentine margins. Material and methods: 60 extracted human molar teeth received slot cavity preparations on mesial and distal surfaces (mesial cervical margin was prepared in enamel and distal in dentine). They were randomly divided into five groups (n?=?12) according to the adhesive system: Group-A: Silorane Bond (S), Group-B: Adper Single Bond 2 (SB), Group-C: Clearfil SE Bond (CSE), Group-D: Single Bond Universal (USel) (selective etch-and-rinse), Group-E: Single Bond Universal (USE) (all-in-one). The preparations were restored using the same resin composite (Filtek Ultimate) except Group A which was restored by Silorane composite. The teeth were thermocycled, immersed in dye, sectioned, and dye penetration was evaluated quantitatively using image analysis. The data were analyzed using the two-way analysis of variance and Bonferroni test. Results: In all groups, there was no statistically significant difference between enamel margins at occlusal and gingival sites (p?>?0.05). The statistical difference between Group-A (S) and Group-B (SB) was significant at all margins. Group-B (SB) presented the greatest microleakage amounts at all margins and the highest scores were obtained in the dentine. Likewise, SB demonstrated statistically significant differences between dentine and enamel margins (occlusal and gingival)(p?<?0.05). Conclusion: All adhesive systems showed similar microleakage values between enamel margins in occlusal and gingival regions. However, when the gingival margin is located in the dentine, etch&rinse adhesive systems may not be a choice in terms of microleakage prevention.     

The effects of self-etch bio-active dental adhesive systems on bacterial microleakage

The aim of this in vitro study was to evaluate the effects of bio-active and non-bio-active self-etch adhesive sytems on bacterial microleakage of class II box cavities with restoration margins in dentin. Two bio-active (Clearfil Protect Bond and F1 Bond II) and two nonbio-active (Clearfil SE Bond and Clearfil s3 Bond) adhesive systems were selected for the study. Eighty mesial and distal class II box cavities were prepared on fourty sound human third molar teeth. The teeth were then divided into four groups with 10 teeth in each group. Groups were restorated using different adhesive systems. The restored specimens were immersed into a culture medium containing streptococcus mutans for bacterial microleakage test. Serial sections of the specimens were used to evaluate the bacterial lekage by using light microscope. The data obtained from the test of bacterial microleakage was evaluated using 2-way mixed analysis of variance (p < 0.05). Statistical analysis showed significant differences between the groups (p < 0.05). Nevertheless it was observed that none of the tested adhesive systems including the bio-active ones were successfull in eliminating bacterial microleakage.     

Effect of different dentin adhesives and application modes on sealing ability of amalgam restorations

Purpose: The aim of the study was to evaluate the sealing ability of bonded amalgam restorations using different adhesive materials with different adhesive application methods including amalgam bonding application. Materials and methods: The prepared Class-V cavities were randomly assigned to four application groups of four tested dual-curing dentin adhesives (Scotchbond Multi-Purpose Plus, XP Bond, Xeno IV and Clearfil Liner Bond 2V), dual-curing resin-based cement (Panavia F2.0) and a control group (unlined amalgam). Group 1 adhesives were applied according to the instructions for direct light-curing, Group 2 chemical-curing mode was applied according to the manufacturer’s amalgam bonding instructions. Group 3 adhesives were first applied in light-curing mode, and then amalgam bonding adhesive was applied. Group 4 adhesives were first applied in chemical-curing mode, followed immediately by light-curing mode. After that, amalgam adhesive parts were applied; then, the amalgam was condensed and carved. After storage for 24 h in distilled water at 37 °C, restorations were finished and polished. The teeth were then thermocycled (500 cycles between 5 and 55 °C), and the specimens were examined for microleakage using methylene blue as a marker. Results: Compared to the control group, the adhesive application modes significantly reduced microleakage for both dentin and enamel margins (p < 0.05). In dentin margins of the adhesives tested, Group 4 showed the lowest leakage score. On the enamel margins for Scotchbond Multi-Purpose Plus and XP Bond, Group 1 showed the highest microleakage (p < 0.05). Conclusion: According to marginal sealing ability and ease of application, Group 2 was recommended for the etch and rinse systems, and Group 4 was also recommended for the self-etch systems under amalgam restorations.     

The role of surface-sealant application on bond effectiveness of all-in-one self-etch adhesives

Purpose: To examine microleakage around Class-V restorations bonded with 3 current all-in-one adhesive systems in the presence or absence of surface-sealant in different evaluation groups.

Materials and Methods: Clearfil S3 Bond, G-Aenial Bond, and Optibond All-in-One (AiO), were used in the Class-V cavities in accordance with the manufacturer’s instructions (control group) or were additionally combined with Fortify Plus surface-sealant (surface-sealant group). The two main treatment groups of the dentin adhesives were subdivided into four different evaluation groups (24 h, 6 months, 12 months, and 12 months with two applications); the teeth were immersed in 0.5% methylene blue dye solution for 24 h. Samples were then sectioned longitudinally in a bucco-lingual direction and evaluated for microleakage under a stereomicroscope. Dye penetration was scored at the enamel (occlusal) and dentin (gingival) margins.

Results: Microleakage scores were greater at the dentin margins compared with the enamel margins for Clearfil S3 Bond in all evaluation groups, whereas no difference was observed between enamel and dentin microleakage for Optibond AiO. Using Fortify Plus in the enamel margins decreased the microleakage scores of Clearfil S3 Bond. When the control and surface-sealant groups were compared in the G-Aenial Bond enamel margins, the application of surface-sealant significantly reduced microleakage after 6 and 12 months. For Optibond AiO, no statistically significant differences in enamel and dentin margins were observed between the control and surface-sealant application groups.

Conclusion: The application of surface-sealant could be considered appropriate for reducing microleakage in composite resin restorations, but this effect might depend on the dentin adhesive.     

One-year bonding performance of one-bottle etch-and-rinse adhesives to dentin at different moisture conditions

Abstract

This study aimed to investigate the one-year bond strengths to dentin of one-bottle etch-and-rinse adhesive systems applied under different moisture conditions. Class V cavities were prepared in bovine incisors and randomly allocated (n?=?8) according to the type of adhesive system used – SB (Adper? Single Bond 2); PB (Prime & Bond 2.1); and XPB (XP Bond) – and the moisture condition kept in the cavity – moist, over-wet, and over-dry. Filtek? Z250 was used for teeth restoration. Specimens for microtensile bond strength (µTBS) test were obtained and stored in water for 24?h or 1?year, and submitted to mechanical testing. Data were analyzed using t-tests, ANOVA and the Holm–Sidak post hoc test (α?=?0.05). Weibull analysis was used to verify the reliability of specimens. The type of adhesive and the moisture condition of the substrate affected the µTBS. At 24?h, SB performed better under the moist and over-wet conditions. At 1?year, SB, PB, and XPB showed the greatest percentage reduction at the moist (～38%), over-wet (100%), and over-dry (100%) conditions, respectively. The reliability of adhesives was affected by the variable factors tested. In conclusion, the solvent composition of adhesives and the moisture condition of the substrate play an important role in the bond strength and bonding stability of resin-based restorations, as well as on the reliability of the adhesive interfaces over time.     

The bonding effect of adhesive systems and bulk-fill composites to sound and caries-affected dentine

Purpose: To investigate the influence of adhesive type and increment thickness on shear bond strength of flowable bulk-fill resin composites compared with a flowable conventional resin composite, in both sound and caries-affected dentine.

Methods: Shear bond strength was tested in 100 extracted human molars with coronal dentine caries. Half of the teeth were restored with Adper? Easy Bond and the other half with Adper? Single Bond Plus. Bonded surfaces were restored with Filtek? Ultimate Flow and two bulk-fill composites (SDR and X-tra base) (n = 10 teeth for each subgroup). Restorations of 4 mm were performed with incremental or bulk-fill technique. The shear bond was determined and statistically analysed using three-way ANOVA and Bonferroni multiple comparison post hoc tests (p ≤ 0.05). Dentine–resin interfaces were evaluated by scanning electron microscopy.

Results: For both adhesives, the highest shear bond strength values were obtained for sound dentine. In sound dentine, the highest bond strength observed with Easy Bond when used in 2-mm increments of SDR. In caries-affected dentine, Single Bond in combination with SDR displayed significantly lower bond strength.

Conclusion: There was no significant difference in shear bond strength between the incremental and bulk-fill groups for molars with sound dentine when the etch-and-rinse adhesive system was used; however, for the self-etch adhesive system, incremental application caused higher bond strength than bulk application.     

Sealing effectiveness of fissure sealants bonded with universal adhesive systems: influence of different etching modes

This study compared the sealing effectiveness of fissure sealants bonded to enamel with universal adhesive systems applied in self-etch (SE) or etch-and-rinse (ER) modes. Extracted human molars (n = 216), were randomly assigned into nine groups with respect to etching mode, adhesive system, and the sealant material used (Clinpro/3 M or Giomer-Based BeautiSealant/Shofu): (1) ER + Clinpro (Control); (2) SE/Single Bond Universal (SBU) + ClinPro; (3) ER + SBU + Clinpro; (4) SE/All Bond Universal (ABU) + Clinpro; (5) ER + ABU + Clinpro; (6) SE/Clearfil Universal Bond (CUB) + Clinpro; (7) ER + CUB + Clinpro; (8) SE + BeautiSealant Primer + BeautiSealant; (9) ER/BeautiSealant Primer + BeautiSealant. Following thermocycling (1000X) and storage in 0.5% basic fuchsin, microleakage was evaluated quantitatively on tooth sections using imageJ analysis toolkit, and the data were analyzed statistically. The ER Mode significantly reduced the microleakage of universal adhesives. The following statistical ranking was observed with regard to the sealing effectiveness: ER + SBU + Clinpro = ER + ABU + Clinpro = SE/SBU + Clinpro = ER + CUB + Clinpro > SE/ABU + Clinpro = SE/CUB + Clinpro > ER + BeautiSealant Primer + BeautiSealant = ER + Clinpro (Control) = SE/BeautiSealant Primer + BeautiSealant. While the tested universal adhesives showed less microleakage on pre-etched enamel, the sealing effectiveness of SBU under SE mode was similar to all universal adhesives under ER mode. In both ER and SE modes, the sealing effectiveness of the giomer-based sealant was comparable to the control group.     

Microleakage in class V cavities prepared using conventional method versus Er:YAG laser restored with glass ionomer cement or resin composite

This study evaluated the effect of tooth preparation method (diamond bur vs. Er:YAG laser) on the microleakage levels of glass ionomers and resin composite. Human permanent premolars (N = 80) were randomly divided into two groups (n = 40). Cavities on half of the teeth were prepared using diamond bur for enamel and carbide bur for dentin and the other half using Er:YAG laser. The teeth were randomly divided into four groups according to the restoration materials, namely (a) ChemFil Rock (CFR), (b) IonoluxAC (IAC), (c) EQUIA system (EQA) and one resin composite (d) AeliteLS (ALS) (n = 10 per group). Microleakage (μm) was assessed at the occlusal and gingival margins after dye penetration (0.5% basic fuchsine for 24 h). On the occlusal aspect, while the cavity preparation types significantly affected the microleakage for CFR (p = 0.015), IAC (p = 0.001) glass ionomer restorations, it did not show significant effect for glass ionomer EQA (p = 0.09) and resin composite ALS (p = 0.2). Er:YAG laser presented less microleakage compared to bur preparation in all groups except for EQA. On the gingival aspect, microleakage decreased significantly for CFR (p = 0.02), IAC (p = 0.001), except for EQA where significant increase was observed (p = 0.001) with the use of Er:YAG laser. Microleakage decrease was not significant at the gingival region between diamond bur and Er:YAG laser for ALS (p = 0.663). At the occlusal and gingival sites in all groups within each preparation method, microleakage level was not significant.     

Efficacy of accelerated aging methods to degrade the adhesive interface of dentin cavities bonded with etch-and-rinse adhesive systems

This study evaluated the bond durability produced by etch-and-rinse (E&R) adhesive systems in response to traditional and accelerated aging methods. Tridimensional dentin cavities were prepared on 80 bovine incisors, which were bonded with a 3-step E&R (Adper Scotchbond Multipurpose Plus – MP) and a 2-step E&R (Adper Single Bond 2 (SB) adhesive systems, and restored with composite. The samples were stored in water for 24 h, and then subjected to each of the aging methods (n = 10): control group – only 24-h storage (not exposed to additional aging), 6- and 12-month water storage, and 10% NaOCl storage. The push-out bond strength test was performed in a universal testing machine. Failure modes were evaluated by scanning electron microscopy. Data were analyzed by two-way ANOVA and Tukey tests (p < 0.05). Aging methods provided statistically similar bond strength for 3-step E&R adhesive system (p > 0.05). 10% NaOCl storage provides statistically similar bond strength values to 6- and 12-month water storage (p > 0.05), which were statistically lower than those provided by 24-h water storage (control group) (p < 0.05). Adhesive failures were more frequent. Aging methods provided different behaviors according to each adhesive system. The accelerated 10% NaOCl storage was effective to decrease bond strength only for 2-step E&R adhesive system.     

Effects of composite viscosity and adhesive curing mode on marginal sealing of restorations

Objectives: Evaluate the influence of composite viscosity, adhesive systems curing mode and artificial aging on marginal sealing of composite resin restorations. Methods: 240 cavities were prepared in bovine incisors. Teeth were divided in two groups: GR – GrandioSO (Voco), conventional viscosity and GF – GrandioSO Heavy Flow (Voco), low viscosity. Each group was divided into 6 subgroups: FM – Futura Bond M (Voco), FDCL and FDCC – Futura Bond DC (Voco), light and chemical cured, CS – Clearfil S³ Bond (Kuraray), CDCL and CDCC – Cleafil DC (Kuraray), light and chemical cured. Half of all specimens were subjected to mechanical (300.000) and thermal cycling (1.000). Marginal gap was measured in an optical microscope. For microleakage, specimens were stained in 50% ammoniacal silver nitrate. Results: For marginal gap mean (μm), significant differences were shown for all factors (p = 0.000). Results for resin were GR: 28.1 and GF: 40.6; for adhesive CDCC: 28.67, CDCL: 32.25, CS: 34.12, FDCL: 36.10, FM: 36.50 and FDCC: 38.46; and for artificial aging WITHOUT: 29.05 and WITH: 39.65. For microleakage mean (mm), there were also differences for all factors (p = 0.000). Results for resin were GR: 2.68 and GF: 3.46; for adhesive FM: 2.85, CDCC: 3.00, FDCL: 3.08, CDCL: 3.15, CS: 3.16 and FDCC: 3.19; and for artificial aging WITHOUT: 2.66 and WITH: 3.48. Conclusion: Composite with conventional viscosity resulted in narrower marginal gaps and less microleakage. CDCC showed less marginal gap formation. The presence of thermo-mechanical cycling increased the values of gap and microleakage.     

Are antibacterial component additions in etchants and adhesives effective against Streptococcus Mutans?

The aim was to investigate the antibacterial activity of various acids and adhesives with and without antibacterial components against Streptococcus mutans. The antibacterial activities of 35% phosphoric acid (Ultra-Etch), 37% phosphoric acid with benzalkonium chloride (Etch-37), adhesive with chlorhexidine (Peak Universal Bond) and without any agent (PQ1) were investigated by agar-diffusion test. The inhibition-zones were measured after 48 h of incubation. For the tooth-cavity model test; cylindrical cavities were prepared on occlusal dentin surfaces of human molars and divided into four groups (n = 10 cavity/group). Group 1: Ultra-Etch + Peak Universal Bond, Group 2: Ultra-Etch + PQ1, Group 3: Etch-37 + PQ1 were applied. The fourth group without any agent application served as control. The teeth were immersed in 5.8 × 10⁶ cfu/ml of S. mutans solution to infect the cavities for 72 h before the application of the groups. After 72 h, dentin chips were collected from the cavity walls with burs for bacterial counting. Statistical analysis was performed by ANOVA, Bonferroni and Dunnett C tests (p < 0.05). Ultra-Etch and Etch-37 performed similar antibacterial activities in agar-diffusion test. Both acids showed better antibacterial activity compared to adhesives (p < 0.05). The antibacterial activity of PQ1 and Peak Universal Bond was observed to be inactivated by light-polymerization. According to the tooth-cavity model; Group I, II, and III demonstrated reduction in bacterial number and there was no significant difference between them. Antibacterial component additions in etchant and adhesive did not show superior antibacterial activity against S. mutans in both in vitro tests.     

The Effect of Decalcified Root Surfaces on Dentinal Bond Strength

Microtensile bond strengths of current dentin adhesives to intact and decalcified root surfaces were evaluated. Two hundred and twenty-four extracted human incisors were divided into two groups as intact (IRD) and decalcified (DRD). The roots of DRD teeth were placed in a demineralization solution to produce artificial carious-like lesions. Root surfaces were slightly ground and treated with either Scotchbond Multi-Purpose (SMP), Adper Single Bond Plus (SBP), Adper Easy Bond (AEB), Scotchbond SE (SSE), Clearfil SE Bond (CSE), Clearfil Protect Bond (CPB), Clearfil Tri-S Bond (CTS), FL-Bond II (FLB), XP Bond (XPB), iBond (IB), AdheSE Bond (ASE), Optibond Solo Plus (OSP), Prelude Dental Adhesive (PDA), and G-Bond (GB). Composite build-ups were formed on the bonded surfaces. After thermocycling, hour-glass shaped specimens with an area of 1 mm² at the bonded interface were subjected to microtensile testing. Resin–dentin interfaces were observed with SEM. Kruskal Wallis and Mann Whitney-U tests were used for statistical analysis. There was not significant difference between bond strengths to intact and decalcified dentin, with the exception of ASE and CSE, which had higher values to IRD (p < 0.05). SSE and CTS were the adhesives that showed higher bond strengths to DRD than to IRD, however the difference was not significant (p > 0.05). The self-etch adhesives performed better on both IRD and DRD surfaces than etch-and-rinse systems.     

Effect of caries removal techniques on bond strength to caries affected dentin on gingival wall: AFM observation of dentinal surface

Objective: The purpose of this study was to evaluate the effect of different caries removal techniques on the bond strength of two adhesive systems. Materials and Methods: Seventy human molar teeth that had proximal carious lesions were randomly divided into four groups according to the technique used to remove the caries: a conventional steel bur, an Er:YAG laser, a chemomechanical Carisolv^® gel, and air polishing. The groups were then divided into two subgroups according to the adhesives used: Clearfil S³ (Kuraray Co., Ltd, Tokyo, Japan) and Adper SE Plus (3 M ESPE, St Paul, MN, USA). The enamel and superficial dentin of the crown was flattened and caries were removed using different methods. Teeth were restored with composite and three 1 mm² stick-shaped microtensile specimens were prepared from each tooth. For each removal technique, the surface roughness of one dentin sample was analyzed using atomic force microscopy (AFM). The microtensile bond strength data were then analyzed using a two-way ANOVA, Kruskal–Wallis and Mann–Whitney U tests, and multiple comparison tests (p = 0.05). Results: The two-way ANOVA showed that the effects of the cavity preparation techniques and adhesive systems and their interaction were statistically significant (p < 0.05). The μTBS values were highest when bonding with Adper SE Plus to cavities prepared with the steel bur (37.20 ± 11.65 MPa) and lowest when bonding with Clearfil S³ Bond to cavities prepared with the Er:YAG laser (16.74 ± 6.95 MPa). Conclusion: The caries removal techniques affected the bond strength values of the self-etch adhesive systems.     

Load-bearing capacity and failure types of premolars restored with sonic activated bulk-fill-, nano-hybrid and silorane-based resin restorative materials

This study evaluated the load-bearing capacity of premolars restored with three types of resin composite materials in mesio-occluso-distal (MOD) cavities. Extracted human premolars (N = 30, n = 10 per group) were randomly divided into three groups; MOD cavities were prepared and restored with one of the following resin materials: Group BFC: Bulk-fill composite (SonicFill, Kerr Corporation), Group NC: Nanohybrid resin composite (Filtek Z550, 3M ESPE), Group SC: Silorane-based composite (Filtek Silorane, 3M ESPE). For NC Clearfil SE Bond (Kuraray, Japan) and for SC, Silorane adhesive resin (Filtek Silorane System Adhesive, 3M ESPE) were used. The cavities in NC and SC groups were restored incrementally, while those in BFC groups were restored in bulk. After water storage (24 h, 37 °C), each tooth was subjected to compressive loading with a stainless steel ball (diameter: 4 mm) perpendicular to the occlusal surface (1 mm/min). Failure types were categorized according to being repairable or irrepairable. Data were statistically analysed using Kruskal-Wallis test (α = 0.05). Two-parameter Weibull distribution values including the Weibull modulus, scale (m) and shape (0) values were calculated. Fracture resistance of premolars restored with BFC (829.84), NC (701.35) and SC (807.73) did not show significant difference (p = 0.72). Weibull distribution presented lower shape (0) for SC (m = 2.77) and NC (m = 3.09) compared to BFC (m = 5.01). The incidence of repairable failures was more common in BFC (80%) compared to NC (60%) and SC (50%). Adhesive failures were more often observed in NC (80%) and SC (70%) groups.     

Effect of Different Restorative Materials on Microleakage of Ozone Gas and Traditional Cavity Disinfectant Applied Teeth

The aim of this in vitro study is to investigate the effects of ozone and conventional cavity disinfectant on microleakage at the cavities which are restorated with different restorative materials. Ninety human molar teeth were used in this study. Black V cavities are prepared on buccal surfaces of teeth. Teeth are divided to 3 groups which contains 30 teeth. Group 1: ozone applied; Group 2: 2% chlorhexidine applied; Group 3: any disinfectant is not applied. And then all groups are divided to three subgroups. All subgroups are restored with silorane, ormocer, and traditional composite according to the manufacturer’s directions. Sections were examined under a microscope. Occlusal and gingival microleakage values by a separate researcher and scores were recorded. Statistically results were reviewed with ANOVA and Kruskal–Wallis Tests. Statistically significant difference of microleakage between cavity disinfectant and control groups’ occlusal and gingival lines was not found (p > 0.05). There was no differences at occlusal lines of composite subgroups (p > 0.05) but also significant difference at gingival lines was found (p < 0.05). Statistically significant difference was found among the composite materials, between chlorhexidine and control groups’ gingival lines. The most successful results at gingival lines were found with silorane.     

A comparative study on monomer elution and cytotoxicity of different adhesive restoration materials

This study evaluated monomer release and cytotoxicity of different adhesive restoration materials used for dental restorations. The extracts (1, 2, and 7 days) of three types of adhesive dental restoration materials, [Quixfill (QF), Silorane Restorative (SR), and Ketac N 100 Restorative (KR)], and the adhesive resins, [XP Bond (XP), Silorane Primer (SP), Ketac N 100 Primer (KP), and Silorane Bond (SB)] were analyzed using high performance liquid chromatography/mass spectrometry (HPLC-MS). The cytotoxicity levels were determined at different time points (24, 48, and 72 h) of cell culture using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay. All adhesive resin materials showed monomer release at varying amounts with the highest release after 7 days. The lowest amount of release was observed in QF and the highest with KP. Bis-Phenol A (BPA) was not detected in SP and KR that contain bisphenol-A diglycidyl ether dimethacrylate (bis-GMA). Decamethylpenthasiloxane (D5) was not eluted from SR. Except for SR and QF, all other adhesive restoration materials showed different degrees of toxicity along with different monomer release kinetics. The correlation between the monomer release and cytotoxicity of the materials indicated that the cytotoxicity of the materials increased with the monomer release (Spearman’s rho correlation coefficient – r). The correlation after 48 h was statistically significant (r = ?0.342, p = 0.017).     

Extraction relationship of Li+ and H+ using tributyl phosphate in the presence of Fe(III)

ABSTRACT

During the extraction of lithium from high Mg-containing salt lake brines by tributyl phosphate (TBP) in the presence of Fe(III), H⁺ is used to stabilize Fe(III). However, the distribution ratio of H⁺ (D_H) is 4–6 times higher than that of Li⁺ (D_Li), which affects the extraction of Li⁺ significantly. In this study, the competition mechanism between H⁺ and Li⁺ was investigated by spectral analysis and thermodynamic equilibrium. The extracted species are determined as HFeCl₄ · 2TBP and LiFeCl₄ · 2TBP for H⁺ and Li⁺, respectively. The apparent equilibrium constants are K_H = 799.8 and K_Li = 120.6, respectively. Both equilibrium constants and the distribution ratios for H⁺ and Li⁺ extraction show that extraction of H⁺ is stronger than Li⁺.     

Effect of saliva contamination on shear bond strength and microleakage of one-bottle etch-and-rinse and self-etch adhesives: scanning electron and confocal laser microscopic analyses

Purpose: To evaluate the effect of saliva contamination on shear bond strength, microleakage, and microstructure of the adhesive interface in two different adhesive systems by using scanning electron microscopy (SEM) and confocal laser microscopy (CLSM). Materials and methods: Randomly, 228 third molars were allocated to six groups for an etch-and-rinse adhesive One-Step Plus (Bisco Inc.) and a self-etch adhesive G Bond (GC Corp.): Group 1 – manufacturer’s instructions were followed; Group 2 – involved contamination and drying before adhesive application; Group 3 – involved contamination, washing, and blot drying before adhesive application; Group 4 – involved contamination, etching, washing, and blot drying before adhesive application; Group 5 – involved contamination and drying after adhesive application, followed by adhesive reapplication; Group 6 – involved contamination and washing after adhesive application, followed by adhesive reapplication. Shear bond strength was tested after specimens were stored in distilled water at 37?°C for 24?h. Specimens were evaluated under a stereomicroscope for microleakage. Dentin–resin interfaces were evaluated by SEM and CLSM. Results: Group 2 for One-Step Plus and Group 3 for G Bond showed significantly lower bond strengths than control groups. Microleakage values were significantly greater at dentin than at enamel margins for all groups. In Group 2, for both adhesive systems, the highest microleakage was observed at dentin margins. Further, dentin–adhesive interfaces were not uniform and gaps were found by SEM and CLSM. Conclusions: The SEM and CLSM images demonstrated high variability of dentin–resin interfaces among saliva-contaminated groups. Rinsing the saliva and re-applying adhesive might be the best way to reduce the effect of saliva contamination on bond strength and microleakage.     

A novel chemical aging method for evaluating degradation of resin-dentin bond: a preliminary study

Purpose: to investigate the use of NaOH solution as storage medium on dentin micro-tensile bond strengths (MTBS) and the micromorphology of resin–dentin interfaces. Materials and Methods: mid-coronal dentin was exposed for 45 human third molars. One of five dentin adhesives investigated was applied to each dentin surface, followed by placement of a resin composite from the same manufacturer (Clearfil S3 Bond + Clearfil Majesty, Clearfil SE Bond + Clearfil Majesty, Kuraray Co. Ltd; Adper Easy One + Z250, Adper Single Bond 2 + Z250, 3M ESPE; Gluma Comfort Bond + Charisma, Heraeus Kulzer). Bonded specimens were sectioned through resin–dentin interfaces into multiple beams with a cross-sectional area of about 1 mm². The beams were kept in 10 wt% NaOH solution at 37 °C for 0, 2, 4, 6, 8, 10, or 12 h respectively prior to MTBS evaluation. The MTBS data were analyzed statistically. Failure modes were determined by stereomicroscopy. Representative fractured surfaces and resin–dentin interfaces were examined by scanning electron microscopy. Resin–dentin interfaces were also analyzed by transmission electron microscopy (TEM). Results: dentin MTBS decreased significantly with increased storage time in NaOH. Micro-gaps appeared along the resin–dentin interfaces after NaOH treatment and became wider over time. An electron-dense hybrid layer was observed by TEM in the control group, while an electron-lucent band was detected at the resin–dentin interfaces of specimens treated with NaOH for 8 h. Conclusion: aging of resin–dentin bonds in NaOH solution may be used as an expedited chemical aging method for evaluating degradation of dentin bond.     

Isomer Directed Synthesis of Two 3D Cadmium(II) Compounds: Structure Variation and Energetic Performance

Two inorganic mixtures of copper and sodium compounds have been synthesized and characterized with different measurement techniques. The thermal property of these mixtures has been studied to low temperature up to 223 from 573 K with DSC. The specific heat capacity of this mixture has been measured in atmospheric O₂ at a rate of 10 K min^?1 from 573 to 223 K and vice versa in two thermal cycles. The net specific heat capacity of these mixtures is found endothermic in first and second thermal cycles. The net specific heat capacity of 0.5Cu₂(PO₄)(OH); 3.5CuH(PO₄)₂·H₂O; 2NaHSO₄·H₂O (CuPHS) during first thermal cycle is ?71203.05 J kg^?1 K^?1 and in second thermal cycle is ?73881.67 J kg^?1 K^?1 between temperature range of 303–223 K. The net specific heat capacity of mixture 0.5Cu₂(PO₄)(OH); 3.5CuH(PO₄)₂; 2Na₂SO₄(CuPS) in first thermal cycle is ?21158.37 J kg^?1 K^?1 and in second thermal cycle is?45739.92 J kg^?1 K^?1 between temperature range of 298–573 K. As both mixtures are endothermic in nature in all cycles, it can be used as heat storage material.The average crystallite size of mixture 0.5Cu₂(PO₄)(OH); 3.5CuH(PO₄)₂·H₂O; 2NaHSO₄·H₂O and 0.5Cu₂(PO₄)(OH); 3.5CuH(PO₄)₂; 2Na₂SO₄ is ~47 and ~17.3 nm, respectively.