scholarly journals Shear and tensile bond strengths of autoclaved aerated concrete (AAC) masonry with different mortar mixtures and thicknesses

2021 ◽  
Vol 1 (1) ◽  
pp. 20-31
Author(s):  
Raghav Tandon ◽  
Sanjeev Maharjan ◽  
Suraj Gautam

Autoclaved aerated concrete (AAC) blocks are commonly used for masonry walls. In order to understand the strength of AAC masonry, it is essential to assess the tensile and shear bond strengths of the AAC block-mortar interface for various mortar combinations. This research investigates the bond strength of AAC block mortar interface made up of a) polymer modified mortar (PMM) and b) ordinary cement sand mortar of 1:4 or 1:6 ratio with thickness of 10mm, 15mm or 20mm. A thin cement slurry coating was applied on the block surface before placing the cement sand mortar in the masonry. For all types of interface, shear bond strength of masonry was studied using a triplet test, while the tensile bond strength was determined through a cross-couplet test. Among the cement sand mortar used in this study, cement sand mortar of ratio 1:4 and thickness 15mm showed the maximum shear strength of 0.13MPa with the failure of blocks as the predominant failure while the PMM had shear bond strength of 0.12MPa with the failure of blocks as the predominant failure type. However, in case of the tensile bond strength testing, PMM showed the tensile bond strength of 0.19MPa, which was highest among all the test specimens used in this study. Considering both the tensile and shear bond strengths of the AAC masonry and based on the observed failure pattern, among all the combinations used in the experiment, either PMM or cement-sand mortar of ratio 1:4 and thickness of 15mm can be chosen for the AAC masonry.

2014 ◽  
Vol 85 (4) ◽  
pp. 645-650 ◽  
Author(s):  
Laura Mews ◽  
Matthias Kern ◽  
Robert Ciesielski ◽  
Helge Fischer-Brandies ◽  
Bernd Koos

ABSTRACT Objective:  To examine differences in the shear bond strength of orthodontic brackets on differently mineralized enamel surfaces after applying a caries infiltrant or conventional adhesive. Materials and Methods:  A total of 320 bovine incisors were assigned to eight pretreated groups, and the shear force required for debonding was recorded. Residual adhesive was evaluated by light microscopy using the adhesive remnant index. Statistical analysis included Kolmogorov-Smirnov, analysis of variance (ANOVA), and Scheffé tests. Results:  The highest bond strength (18.8 ± 4.4 MPa) was obtained after use of the caries infiltrant. More residual adhesive and fewer enamel defects were observed on infiltrated enamel surfaces. Brackets on demineralized enamel produced multiple enamel defects. Conclusions:  Acceptable bond strengths were obtained with all material combinations. A caries-infiltrant applied before bracket fixation has a protective effect, especially on demineralized enamel.


2014 ◽  
Vol 15 (6) ◽  
pp. 688-692 ◽  
Author(s):  
Sukumaran Anil ◽  
Farouk Ahmed Hussein ◽  
Mohammed Ibrahim Hashem ◽  
Elna P Chalisserry

ABSTRACT Objective The purpose of the current in-vivo study was to assess the effect of using 0.12% chlorhexidine (CHX) mouth rinse, before bonding, on shear bond strength of polycarbonate brackets bonded with composite adhesive. Subjects and methods Eighteen orthodontic patients with a mean age 21.41 ± 1.2 years, who were scheduled to have 2 or more first premolars extracted, were included in this study. Patients were referred for an oral prophylaxis program which included, in part, the use of a mouth rinse. Patients were divided into 2 groups, a test group of 9 patients who used 0.12% CHX gluconate mouth rinse twice daily and a control group of 9 patients who used a mouth rinse without CHX, but with same color. After 1 week, polycarbonate brackets were bonded to first premolars with Transbond XT composite adhesive. Premolars were extracted after 28 days and tested for shear bond strength on a universal testing machine. Student's t-test was used to compare shear bond strengths of both groups. Results No statistically significant difference was found in bond strengths’ values between both groups. The test group (with CHX) has mean shear bond strength of 14.21 ± 2.42 MPa whereas the control group (without CHX) revealed a mean strength of 14.52 ± 2.31 MPa. Conclusion The use of 0.12% CHX mouth rinse, for one week before bonding, did not affect the shear bond strength of polycarbonate brackets bonded with Transbond composite. Furthermore, these brackets showed clinically acceptable bond strength. How to cite this article Hussein FA, Hashem MI, Chalisserry EP, Anil S. The Impact of Chlorhexidine Mouth Rinse on the Bond Strength of Polycarbonate Orthodontic Brackets. J Contemp Dent Pract 2014;15(6):688-692.


2016 ◽  
Vol 29 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Li Zhou ◽  
Yuetong Qian ◽  
Kang Gan ◽  
Hong Liu ◽  
Xiuju Liu ◽  
...  

This study was designed to evaluate the shear bond strength of an adhesive/composite system subjected to different pretreated polyetheretherketone (PEEK) surfaces using different thermocycling conditioning methods. A total of 128 specimens were equally divided into four main groups ( n = 32/group): control (no pretreatment), air abrasion, argon plasma pretreatment, and femtosecond laser groups. The surface topographies and surface roughness were observed by atomic force microscopy after different pretreatments. The specimens were bonded with SE Bond/Clearfil AP-X™. All bonded specimens were stored in distilled water at 37°C for 24 h. Afterward, each group was divided into three subgroups ( n = 8/group) as follows: (a) stored in water for 56 h (37°C); (b) thermal aging for 5000 cycles (5°C/55°C); and (c) thermal aging for 10,000 cycles (5°C/55°C). The shear bond strengths were measured. Air abrasion, argon plasma pretreatment, and femtosecond laser significantly strengthened the bond of SE Bond/Clearfil AP-X™ to PEEK composite compared with that without additional pretreatment. In the same surface pretreatment, the shear bond strengths of specimens conditioned using water storage were higher than that using thermocycles (TCs). Additionally, the specimens with 5000 TC showed significantly higher shear bond strength than that with 10000 TC.


2013 ◽  
Vol 38 (2) ◽  
pp. 186-196 ◽  
Author(s):  
Camila Sabatini ◽  
Manthan Patel ◽  
Eric D'Silva

SUMMARY Objective To evaluate the shear bond strength (SBS) of three self-adhesive resin cements and a resin-modified glass ionomer cement (RMGIC) to different prosthodontic substrates. Materials and Methods The substrates base metal, noble metal, zirconia, ceramic, and resin composite were used for bonding with different cements (n=12). Specimens were placed in a bonding jig, which was filled with one of four cements (RelyX Unicem, Multilink Automix, Maxcem Elite, and FujiCEM Automix). Both light-polymerizing (LP) and self-polymerizing (SP) setting reactions were tested. Shear bond strength was measured at 15 minutes and 24 hours in a testing device at a test speed of 1 mm/min and expressed in MPa. A Student t-test and a one-way analysis of variance (ANOVA) were used to evaluate differences between setting reactions, between testing times, and among cements irrespective of other factors. Generalized linear regression model and Tukey tests were used for multifactorial analysis. Results Significantly higher mean SBS were demonstrated for LP mode relative to SP mode (p<0.001) and for 24 hours relative to 15 minutes (p<0.001). Multifactorial analysis revealed that all factors (cement, substrate, and setting reaction) and all their interactions had a significant effect on the bond strength (p<0.001). Resin showed significantly higher SBS than other substrates when bonded to RelyX Unicem and Multilink Automix in LP mode (p<0.05). Overall, FujiCEM demonstrated significantly lower SBS than the three self-adhesive resin cements (p<0.05). Conclusions Overall, higher bond strengths were demonstrated for LP relative to SP mode, 24 hours relative to 15 minutes and self-adhesive resin cements compared to the RMGICs. Bond strengths also varied depending on the substrate, indicating that selection of luting cement should be partially dictated by the substrate and the setting reaction.


2009 ◽  
Vol 79 (3) ◽  
pp. 564-570 ◽  
Author(s):  
Toshiya Endo ◽  
Rieko Ozoe ◽  
Koichi Shinkai ◽  
Makiko Aoyagi ◽  
Hiroomi Kurokawa ◽  
...  

Abstract Objective: To ascertain the effects of repeated bonding on the shear bond strength of orthodontic brackets bonded with a fluoride-releasing and -recharging adhesive system with a self-etching primer in comparison with two other types of adhesive system. Materials and Methods: A total of 48 premolars were collected and divided equally into three groups of 16. Each group was assigned one of three adhesive systems: Transbond XT, Transbond Plus, or a fluoride-releasing and -recharging adhesive system, Beauty Ortho Bond. Shear bond strength was measured 24 hours after bracket bonding, with the bonding/debonding procedures repeated twice after the first debonding. A universal testing machine was used to determine shear bond strengths, and bracket/adhesive failure modes were evaluated with the adhesive remnant index after each debonding. Results: At every debonding sequence, all of these three adhesive systems had a shear bond strength of 6 MPa, which is a minimum requirement for clinical use. Transbond XT and Transbond Plus had significantly higher mean shear bond strengths than did Beauty Ortho Bond at each debonding. No significant differences in mean bond strength were observed between the three debondings in each adhesive system. Bond failure at the enamel/adhesive interface occurred more frequently in Beauty Ortho Bond than in Transbond XT or Transbond Plus. Conclusions: The fluoride-releasing and -recharging adhesive system with the self-etching primer (Beauty Ortho Bond) had clinically sufficient shear bond strength in repeated bracket bonding; this finding can help orthodontists to decrease the risk of damage to enamel at debonding.


1993 ◽  
Vol 20 (3) ◽  
pp. 225-229 ◽  
Author(s):  
W. H. Sam ◽  
S. Y. Chao ◽  
K. H. Chung

The shear bond strength of two adhesives (Concise® and Dyna-Plus® bonding system) with one type of ceramic bracket was determined in this study. There were statistically significant differences between the bond strengths, with Concisereg; recording higher levels than Dyna-Plus®. Failure sites of Dyna-Plus® were revealed at the enamel/resin, resin/resin, and resin/bracket interfaces; that of the Concise® was mainly at the resin/bracket interface.


2020 ◽  
Vol 22 (2) ◽  
Author(s):  
Andrzej Małysa ◽  
Joanna Weżgowiec ◽  
Dariusz Danel ◽  
Klauss Boening ◽  
Katarzyna Walczak ◽  
...  

Purpose: The aim of the study was to evaluate the shear bond strength of CAD/CAM ceramics to dentin after cementation with conventional or self-adhesive resin cements. Methods: Three self-adhesive, self-etching cements (Panavia SA, RelyX U200, Maxcem Elite), and one conventional cement (Panavia V5), were selected to lute three CAD/CAM ceramics (IPS Empress CAD, IPS e.max CAD, IPS e.max ZirCAD) onto the dentin. The bond strength was evaluated using a shear strength test according to the PN-EN ISO 29022:2013-10. Evaluation of the differences was performed using the Statistica software. Failure modes were analyzed using a light microscope. Results: All the studied cements differed (regardless of the ceramic type) in the bond strength. The highest bond strength was observed in Panavia V5, lower – in RelyX U200 and Panavia SA, and the lowest – in Maxcem. For IPS e.max ZirCAD, it was observed that compared to Panavia V5, the other cements were characterized by a significantly higher bond strength. For the IPS Empress CAD and the IPS e.max CAD, Panavia V5 displayed the highest bond strength. For all the studied self-adhesive cements, the failure of adhesion between the cement and dentin was predominant mode. Conclusions: Significant differences were found in the shear bond strengths of the CAD/CAM ceramics luted to dentin using tested self-adhesive and conventional cements. The bond strength depended on the combination of ceramic and cement. The IPS e.max ZirCAD had the highest bond strength to dentin after cementation with RelyX U200, while the IPS Empress CAD and IPS e.max CAD – with Panavia V5.


2013 ◽  
Vol 14 (2) ◽  
pp. 250-254 ◽  
Author(s):  
Muge Aksu ◽  
Ilken Kocadereli

ABSTRACT Purpose To search if the shear bond strengths of brackets would change after two different base-cleaning procedures such as sandblasting or carbide bur cleaning, and to determine if a previously bonded tooth surface had any effect on bond strength. Materials and methods A total of 120 new brackets were first bonded to 120 extracted premolars and then debonded and bond strength was recorded. The debonded brackets were divided into two groups and recycled either by sandblasting or tungsten-carbide bur cleaning. Sixty recycled brackets were divided into two subgroups: In each group; 30 recycled brackets were bonded to unused 30 extracted premolars. The remaining brackets were bonded to 30 previously used premolars. The brackets were debonded again and their bond strengths were remeasured. Results Bond strength of rebonded brackets after sandblasting was not significantly different from that of new brackets while the bond strength of rebonded brackets after carbide bur cleaning group significantly decreased. The previously bonded tooth surface did not affect the bond strength significantly. Clinical significance This study showed that rebonding the brackets after sandblasting supplies sufficient bond strength. Previously bonded tooth surface did not cause a decreasing effect on bond strength. However, when carbide bur cleaning procedure is chosen, the clinician should proceed cautiously. How to cite this article Aksu M, Kocadereli I. Influence of Two Different Bracket Base Cleaning Procedures on Shear Bond Strength Reliability. J Contemp Dent Pract 2013;14(2):250-254.


2021 ◽  
Author(s):  
Xianda Yang ◽  
Lihui Sun ◽  
Jiale Song ◽  
Bensheng Yang ◽  
Chengren Lan

Abstract Bond strength is one of the most important parameters and can affect the macroscopic mechanical properties and the damage state of the rock to some degree. The coarse-grained sandstone with strength of less than 40 MPa was studied by the controlled variable method. The influence of parallel bond strength on the peak strength and failure mode of coarse-grained sandstone was simulated, the evolution law of peak strength and failure mode of bond strength were comprehensively analyzed. The results show that the peak strength of rock was positively correlated with the bond strength, the difference value between tensile and shear crack was negatively correlated with tensile bond strength and positively correlated with shear bond strength. Tensile-shear bond strength ratio less than 0.5, the peak strength of the rock was usually stable at the certain extreme value under a constant tensile bond strength. Tensile crack was negatively correlated with the tensile-shear bond strength ratio, shear crack was positively correlated with the tensile-shear bond strength ratio. The failure mode of coarse-grained sandstone is shear failure. The research results can be used to guide the ground control of other mine stopes or roadways with weak cementation lithology.


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