EFFECT OF NANO SILICA ON CONCRETE BOND STRENGTH MODES OF FAILURE

2017 ◽  
Author(s):  
Mohamed I. Serag
Keyword(s):  
Bond Strength ◽  
Nano Silica ◽  
Modes Of Failure

Interfacial Nanoleakage and Bonding of Self-Adhesive Systems Cured with a Modified-Layering Technique to Dentin of Weakened Roots

2013 ◽  
Vol 38 (5) ◽  
pp. E154-E165 ◽  
Author(s):  
E Mobarak ◽  
R Seyam
Keyword(s):  
Bond Strength ◽  
Repeated Measures ◽  
Adhesive Systems ◽  
Root Canals ◽  
Root Region ◽  
Modes Of Failure ◽  
Group A ◽  
Post Hoc ◽  
Vertise Flow ◽  
Self Etch

SUMMARY Objective The purpose of the study was to evaluate the nanoleakage and bond strength of different self adhesive systems cured with a modified-layering technique (MLT) to dentin of weakened roots. Methods Twenty-one maxillary incisors were decoronated and then root canals were instrumented and obturated with the cold lateral compaction technique. Weakened roots were simulated by flaring root canals until only 1 mm dentin thickness remained. Teeth were distributed into three groups. The canals were backfilled with Vertise Flow (VF group), a self-adhering system, following a modified-layering technique using two light-transmitting posts, sizes 6 and 3. DT Light Post size 2 was cemented using the same material. Remaining roots were prepared and cured in the same way as the VF group. However, in the TS/MF group, Clearfil Tri-S Bond (TS) adhesive and Clearfil Majesty Flow (MF) composite were used, while in the ED/PF group, ED primer II (ED)/Panavia F2.0 (PF) were used. After one week of storage, each root was sectioned to obtain six slices (two slices from each root third: coronal, middle and apical) of 0.9 ± 0.1 mm thickness. Interfacial nanoleakage expression was analyzed using a field emission scanning electron microscope (FEG-SEM), and the micro push-out bond strength (μPOBS) was measured at different root regions. Modes of failure were also determined using SEM. Data were statistically analyzed using two-way analysis of variance with repeated measures and Tukey post hoc test (p≤0.05). Results With MLT, all adhesive systems showed nanoleakage. For μPOBS, there was a statistically significant effect for adhesive systems (p<0.001) but not for root region (p<0.64) or for their interaction (p=0.99). Tukey post hoc test revealed that the bond strength of the VF group was significantly higher than the TS/MF and ED/PF groups for all root regions. Conclusion All of the tested self-adhesive systems cured using MLT had slight nanoleakage and were not sensitive to root regional differences. Self-adhering systems had higher bond strength than self-etch adhesives.

scholarly journals Effect of topical fluoride on microshear bond strength of primary enamel to composite, microhardness of enamel and its surface morphology: An in vitro study

2019 ◽  
Vol 13 (4) ◽  
pp. 305-310
Author(s):  
Mina Biria ◽  
Sajedeh Namaei Ghasemi ◽  
Seyedeh Mahsa Sheikh-Al-Eslamian ◽  
Narges Panahandeh
Keyword(s):  
Bond Strength ◽  
Artificial Saliva ◽  
Morphological Characteristics ◽  
In Vitro Study ◽  
Vitro Study ◽  
Control Group ◽  
Modes Of Failure ◽  
Group 3 ◽  
Microshear Bond Strength

Background. This in vitro study aimed to evaluate the microshear bond strength (μSBS), microhardness and morphological characteristics of primary enamel after treating with sodium fluoride (NaF) and acidulated phosphate fluoride (APF). Methods. Forty-eight primary canines were cut into mesial and distal sections and assigned to five groups randomly: group 1 (immersed in saliva as a control), group 2 (treated with NAF and immersed in saliva for 30 minutes), group 3 (treated with APF and immersed in saliva for 30 minutes), group 4 (treated with NAF and immersed in saliva for 10 days), and group 5 (treated with APF and immersed in saliva for 10 days). Composite resin (Filtek Z250) was bonded on the specimens (n=15) for measuring the μSBS. After storage in 37°C artificial saliva for 24 hours, µSBS and Vickers hardness tests (10 readings) were performed. The data were analyzed using one-way ANOVA and Kolmogorov-Smirnov, Levene’s and Tukey HSD tests (P<0.05). Morphological analysis of enamel and modes of failure were carried out under a scanning electron microscope (SEM) on two remaining specimens. Results. Significant differences in μSBS were only noted between groups 2 and 4 (P=0.024). Group 3 showed a significant decrease in hardness after storage in artificial saliva (P<0.001), with a significantly lower hardness than the other groups (P<0.001). The SEM observations showed irregular particles in groups 3 and 5; uniform, smooth and thin coats were seen in groups 2 and 4. Conclusion. Fluoride therapy with NaF and APF gels prior to restorative treatments had no adverse effects on the microshear bond strength.

scholarly journals The Influence of Different Surface Cleansing Agents on Shear Bond Strength of Contaminated Lithium Disilicate Ceramic: An In Vitro Study

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Taksid Charasseangpaisarn ◽  
Pattarawadee Krassanairawiwong ◽  
Chanidapa Sangkanchanavanich ◽  
Atima Kurjirattikan ◽  
Kanyarak Kunyawatyuwapong ◽  
...  
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Sodium Hydroxide Solution ◽  
Resin Composite ◽  
In Vitro Study ◽  
Lithium Disilicate ◽  
Surface Element ◽  
Similar Amount ◽  
Modes Of Failure

Background and Purpose. Contamination of the lithium disilicate (LDS) during the try-in procedure is unavoidable and may weaken the bond strength of restoration. The purpose of this study was to investigate the efficacy of different surface cleansing agents on the shear bond strength (SBS) of contaminated LDS. Materials and Methods. Seventy LDS specimens were randomly divided into seven groups. The first group was noncontaminated surface (PC). The six other groups were contaminated with the saliva and silicone disclosing medium and treated with no surface cleansing agent (NC); phosphoric acid (PO); Ivoclean (IV); sodium hydroxide solution (NA); Restorative Cleansing Agent (RC); and hydrofluoric acid (HF). Then, LDS specimens were cementated with Panavia V5 to resin composite rod. Each specimen was subjected to an SBS test. The modes of failure was inspected under light microscope. The surface element of each group was examined by SEM-EDS. Results. The results were analyzed with one-way ANOVA and Tamhane’s T2. The mean SBS value of NC was significantly lower than others ( p < 0.05 ), and HF was significantly higher than others ( p < 0.05 ). However, PC, PO, IV, NA, and RC were not significantly different from each other ( p > 0.05 ). The mode of failure was mostly adhesive failure in every group. The surface showed similar amount of elements in every group. Conclusions. The SBS of LDS was reduced by saliva and silicone disclosing medium contamination which can be restored using acid- and alkaline-based surface cleansing agents before the cementation procedure.

scholarly journals Evaluation of Shear-Bond-Strength of Dental Self-Adhering Flowable Resin-Composite versus Total-Etch One to Enamel and Dentin Surfaces: An In-Vitro Study

2019 ◽  
Vol 7 (13) ◽  
pp. 2162-2166 ◽  
Author(s):  
Rasha M. Abdelraouf ◽  
Manar Mohammed ◽  
Fatma Abdelgawad
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Resin Composite ◽  
Testing Machine ◽  
Tooth Surface ◽  
Mean Values ◽  
Modes Of Failure ◽  
Group I ◽  
Permanent Molars

AIM: This study aimed to assess the shear bond strength of a self-adhering flowable resin composite versus a total-etch one to different surfaces of permanent-molars. MATERIAL AND METHODS: Thirty-six sound human permanent molars were used. The teeth were embedded in acrylic blocks, such that their buccal surfaces were shown. The teeth were divided into three groups: Group I: Uncut-Enamel, Group II: Cut-enamel-surfaces with minimal-grinding and Group III: dentin-surfaces. Half of the teeth in each group were used for bonding to a self-adhering flowable resin-composite (Dyad-flow, Kerr, USA). While the other half of each group was bonded to a total-etch flowable resin-composite (Filtek™Z350-XT,3M-ESPE, USA) which necessitate etching and bonding. Teflon-mold was used for constructing resin composite cylinders (3 × 3 mm) over the buccal surfaces. The Dyad-flow was applied in the central hole of the mould placed upon tooth-surface, and then light-cured for 20 seconds. The Filtek-Z350-XT was applied similarly after etching and bonding steps. The teeth were stored in 37°C distilled water for 24 hours. The strength was measured using a universal testing machine and statistically analysed. Modes of failure were studied using digital-microscope. RESULTS: Mean values of shear bond strength for the Dyad and Filtek-Z350-XT in the uncut-enamel were 3.5 and 24.6MPa respectively, while that for cut-enamel were 4.5 and 12.7MPa respectively (Both highly statistically significant P ≤ 0.01) and in dentin were 4.3 and 6.7MPa respectively (Statistically significant P ≤ 0.05). The failure mode for Dyad was mainly adhesive (un-cut or cut-enamel 83.3% adhesive and 16.7% mixed, while in dentin 100% adhesive). While the modes of failure for Filtek-Z350-XT in enamel, either cut or un-cut, were 50% cohesive and 50% mixed, whereas in dentin 100% adhesive. CONCLUSION: Bonding of self-etch ″Dyad-flow″ flowable resin-composite was lower than the total-etch one in enamel and dentin. Thus further material improvement may be required.

Effect of Emulsion Type on Bond Behavior of Asphalt Concrete Layers in Cold Regions

2019 ◽  
Vol 2673 (2) ◽  
pp. 368-378
Author(s):  
Laura Stasiuk ◽  
Haithem Soliman ◽  
Ania Anthony
Keyword(s):  
Bond Strength ◽  
Asphalt Concrete ◽  
Failure Surface ◽  
Type B ◽  
Cold Regions ◽  
Modes Of Failure ◽  
Peak Shear Stress ◽  
Tack Coat ◽  
Interlayer Shear Strength ◽  
Term Performance

Tack coat materials, which are typically emulsified bituminous products, are used to provide a sufficient bond between asphalt concrete (AC) layers/lifts. Owing to construction limitations and severe temperature variations in cold regions, agencies are investigating the use of fast curing and non-tracking emulsions as tack coat materials. The objective of this study is to evaluate the performance of various tack coat products in cold climates. Several tack coat products were installed during a field study in Saskatchewan, Canada. The tack coat products included slow setting, medium setting, and three proprietary fast curing/non-tracking emulsions. Core samples were collected three weeks after construction to evaluate the initial interlayer shear strength (ISS) for typical construction conditions in cold regions. Although the ISS values for all of the products, except one SS-1 section, varied in a narrow range, this does not indicate that all products will have a similar long-term performance. The modes of failure for the bond strength samples were classified into two types according to the shape and location of the failure surface: type A and type B. Failure type B indicates that the tack coat material can successfully provide sufficient bond strength to make the two AC lifts behave as one thick homogenous layer. The results showed that the failure mode should be included as an evaluation criterion in addition to ISS. The results showed that the energy required to reach peak shear stress is a comprehensive parameter that should also be considered when evaluating tack coat materials.

Assessment of mechanical strength of nano silica concrete (NSC) subjected to elevated temperatures

2019 ◽  
Vol 10 (1) ◽  
pp. 90-109 ◽  
Author(s):  
Hala Mohamed Elkady ◽  
Ahmed M. Yasien ◽  
Mohamed S. Elfeky ◽  
Mohamed E. Serag
Keyword(s):  
Elevated Temperature ◽  
Bond Strength ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Nano Silica ◽  
Content Type ◽  
Post Exposure ◽  
Concrete Mix ◽  
Bond Strengths

Purpose This paper aims to inspect the effect of indirect elevated temperature on the mechanical performance of nano silica concrete (NSC). The effect on both compressive and bond strengths is studied. Pre- and post-exposure to elevated temperature ranges of 200 to 600°C is examined. A range covered by three percentages of 1.5, 3 and 4.5 per cent nano silica (NS) in concrete mixes is tested. Design/methodology/approach Pre-exposure mechanical tests (normal conditions – room temperature), using 3 per cent NS in the concrete mix, led to the highest increase in both compressive and bond strengths (43 per cent and 38.5 per cent, respectively), compared to the control mix without NS (based on 28-day results). It is worth noticing that adding NS to the concrete mixes does not have a significant effect on improving early-age strength. Besides, permeability tests are performed on NSC with different NS ratios. NS improved the concrete permeability for all tested percentages of NS. The maximum reduction is accompanied by the maximum percentage used (4.5 per cent NS in the NSC mix), reducing permeability to half the value of the concrete mix without NS. As for post-exposure to elevated-temperature mechanical tests, NSC with 1.5 per cent NS exhibited the lowest loss in strength owing to indirect heat exposure of 600°C; the residual compressive and bond strengths are 73 per cent and 35 per cent, respectively. Findings The dispersion technique of NS has a key role in NSC-distinguished mechanical performance with NSC having lower NS percentages. NS significantly improved bond strength. NS has a remarkable effect on elevated temperature endurance. The bond strength of NSC exposed to elevated temperatures suffered faster deterioration than compressive strength of the exposed NSC. Research limitations/implications A special scale factor needs to be investigated for the NSC. Originality/value Although a lot of effort is placed in evaluating the benefits of using nano materials in structural concrete, this paper presents one of the first outcomes of the thermal effects on concrete mixes with NS as a partial cement replacement.

scholarly journals Bonding of contemporary glass ionomer cements to different tooth substrates; microshear bond strength and scanning electron microscope study

2015 ◽  
Vol 09 (02) ◽  
pp. 176-182 ◽  
Author(s):  
Aliaa Mohamed El Wakeel ◽  
Dina Wafik Elkassas ◽  
Mai Mahmoud Yousry
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Bond Strength ◽  
Nano Particles ◽  
Glass Ionomer ◽  
Scanning Electron Microscope Study ◽  
Modes Of Failure ◽  
Occlusal Surfaces ◽  
Microshear Bond Strength ◽  
Scanning Electron

ABSTRACT Objective: This study was conducted to evaluate the microshear bond strength (μSBS) and ultramorphological characterization of glass ionomer (GI) cements; conventional GI cement (Fuji IX, CGI), resin modified GI (Fuji II LC, RMGI) and nano-ionomer (Ketac N100, NI) to enamel, dentin and cementum substrates. Materials and Methods: Forty-five lower molars were sectioned above the cemento-enamel junction. The occlusal surfaces were ground flat to obtain enamel and dentin substrates, meanwhile the cervical one-third of the root portion were utilized to evaluate the bonding efficacy to cementum substrate. Each substrate received microcylinders from the three tested materials; which were applied according to manufacturer instructions. μSBS was assessed using a universal testing machine. The data were analyzed using two-way analysis of variance (ANOVA) and Tukey’s post-hoc test. Modes of failure were examined using stereomicroscope at ×25 magnification. Interfacial analysis of the bonded specimens was carried out using environmental field emission scanning electron microscope. Results: Two-way ANOVA revealed that materials, substrates and their interaction had a statistically significant effect on the mean μSBS values at P values; <0.0001, 0.0108 and 0.0037 respectively. RMGI showed statistically significant the highest μSBS values to all examined tooth substrates. CGI and RMGI show substrate independent bonding efficiency, meanwhile; NI showed higher μSBS values to dentin and cementum compared to enamel. Conclusion: Despite technological development of GI materials, mainly the nano-particles use, better results have not been achieved for both investigations, when compared to RMGI, independent of tooth substrate.

scholarly journals Effect of Luting Cement Film Thickness on the Pull-Out Bond Strength of Endodontic Post Systems

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3082
Author(s):  
Khalil Aleisa ◽  
Syed Rashid Habib ◽  
Abdul Sadekh Ansari ◽  
Ragad Altayyar ◽  
Shahad Alharbi ◽  
...  
Keyword(s):  
Bond Strength ◽  
Film Thickness ◽  
Testing Machine ◽  
Resin Cement ◽  
Cement Interface ◽  
Pull Out ◽  
Modes Of Failure ◽  
Fiber Posts ◽  
Luting Cement ◽  
Group A

Optimal bond strength between the prefabricated post/dowel to the surrounding dentin is essential. The present study aimed to analyze and compare the effect of three different cement film thicknesses on the pull-out bond strength of three different prefabricated post systems. Extracted natural teeth (N = 90) with similar root dimensions were acquired. Teeth were mounted in resin blocks, endodontically treated, sectioned at cemento-enamel junction, divided into three groups (A: Parapost Fiber Lux plus; B: 3M ESPE Relyx fiber post; and C: Parapost XP), and stored. Uniform post spaces were prepared for the groups (A and C: Length = 8 mm, Width = 1.5 mm; B: Length = 8 mm, Width = 1.6 mm). Each group (N = 30) was further subdivided into three subgroups (n = 10) based on the size (4, 5, and 6) of the post and cemented with resin cement (MultiLink-N, Ivoclar Vivadent). After thermocycling, the specimens were subjected to a pull-out test using a universal testing machine, and tensile force was recorded (MPa). Digital microscopic evaluations were performed for modes of failure. ANOVA and Tukey-HSD tests were used for statistics. Significant differences were observed for each tested material (p = 0.000). The lowest and highest bond strength values were recorded for Group C (Titanium post) and Group A (000), respectively. Multiple comparisons showed significance (p < 0.05) among all the groups, except for space 1 and space 2 (p = 0.316) for Group A. Most of the failures occurred within the cement-dentin and post-cement interface (Adhesive failures, 73.5%). An increase in the luting cement film thickness results in the decrease in pull-out bond strength of prefabricated posts luted with resin cement, irrespective of the type/material/shape of the post. The serrated fiber posts showed the highest pull-out bond strength compared to the smooth surfaced fiber posts or serrated metal posts. Increased pull-out bond strengths were observed when appropriate post space was created with the same sized drill as the post size.

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