scholarly journals Imagistic Evaluation of the Orthodontics Interfaces

2013 ◽  
Vol 8-9 ◽  
pp. 317-326
Author(s):  
Cosmin Sinescu ◽  
Adrian Manescu ◽  
Meda Lavinia Negrutiu ◽  
Mihai Rominu ◽  
Liviu Marşavina ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Tensile Bond Strength ◽  
Scientific Interest ◽  
Surface Conditioning ◽  
Strength Tests ◽  
Artificial Surface ◽  
Bracket Base ◽  
Destructive Methods

In orthodontics, the scientific interest regarding adhesion is focused on optimizing adherents: metallic or aesthetic bracket base conditioning, creating aesthetic brackets with improved mechanical properties, enamel conditioning and artificial surface conditioning (aesthetic veneers and crowns). In order to investigate the interfaces between adherents there are several invasive (destructive) methods such as tensile bond strength tests, shear bond strength tests and microleakage tests.

scholarly journals Assessment of the mechanical properties of glass ionomer cements for orthodontic cementation

2012 ◽  
Vol 17 (6) ◽  
pp. 154-159 ◽  
Author(s):  
Marcel M. Farret ◽  
Eduardo Martinelli de Lima ◽  
Eduardo Gonçalves Mota ◽  
Hugo Mitsuo S. Oshima ◽  
Gabriela Maguilnik ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Resin Modified Glass Ionomer ◽  
Strength Tests ◽  
Diametral Tensile Strength

OBJECTIVE: To evaluate the mechanical properties of three glass ionomers cements (GICs) used for band cementation in Orthodontics. METHODS: Two conventional glass ionomers (Ketac Cem Easy mix/3M-ESPE and Meron/Voco) and one resin modified glass ionomer (Multi-cure Glass ionomer/3M-Unitek) were selected. For the compressive strength and diametral tensile strength tests, 12 specimens were made of each material. For the microhardness test 15 specimens were made of each material and for the shear bond strength tests 45 bovine permanent incisors were used mounted in a self-cure acrylic resin. Then, band segments with a welded bracket were cemented on the buccal surface of the crowns. For the mechanical tests of compressive and diametral tensile strength and shear bond strength a universal testing machine was used with a crosshead speed of 1,0 mm/min and for the Vickers microhardness analysis tests a Microdurometer was used with 200 g of load during 15 seconds. The results were submitted to statistical analysis through ANOVA complemented by Tukey's test at a significance level of 5%. RESULTS: The results shown that the Multi-Cure Glass Ionomer presented higher diametral tensile strength (p < 0.01) and compressive strength greater than conventional GICs (p = 0.08). Moreover, Ketac Cem showed significant less microhardness (p < 0.01). CONCLUSION: The resin-modified glass ionomer cement showed high mechanical properties, compared to the conventional glass ionomer cements, which had few differences between them.

Analysis of surface conditioning methods on core-veneer bond strength of CAD/CAM zirconia restorations

2020 ◽  
pp. 1-11
Author(s):  
Anip K. Roy ◽  
Govind N. Prasad ◽  
Tushar V. Bhagat ◽  
Saurabh Chaturvedi ◽  
Vishwanath Gurumurthy ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Group Iv ◽  
Control Group ◽  
Group Iii ◽  
Surface Conditioning ◽  
Group I ◽  
Alumina Particles ◽  
Scanning Electron

BACKGROUND: The increased strength of zirconia has resulted in its widespread application in clinical dentistry. Nevertheless, the fracture of veneering porcelains remains one of the key reasons of failure. OBJECTIVE: The objective of this study was to compare and analyze the influence of surface conditioning methods on the core-veneer bond strength of zirconia restorations. METHODS: Thirty specimens of zirconia core with sizes 10 × 5 × 5 mm were layered with porcelain of sizes 5 × 3 × 3 mm. On the basis of different surface conditioning methods, four groups were made: Group I: abrasion with airborne alumina particles of 110 μm size, Group II: sandblasting with silica coated alumina particles of 50 μm in size, Group III (modified group): alteration with a coating of zirconia powder prior to sintering, and Group IV (control group): metal core specimens. The shear force of all specimens was tested using a universal testing machine with a 0.5 mm/min crosshead speed. One-way analysis of variance (ANOVA) and Tukey’s post hoc pair wise comparison (p= 0.05) were performed to analyze the shear bond strength. A scanning electron microscope was used to assess the fractured specimens. RESULTS: A statistically significant difference was noted between the groups. The mean value of shear bond strength was 40.25 MPa for Group I, 41.93 MPa for Group II, 48.08 MPa for Group III and 47.01 MPa for Group IV. CONCLUSIONS: The modified zirconia group and control group demonstrated a significantly higher mean bond strength than that of Group I, where airborne particle abrasion was used. The scanning electron microscope showed that cohesive fracture in the porcelain veneers was the main problem of failure in altered zirconia. The modified zirconia specimens in Group III demonstrated significantly improved values of shear bond strength.

scholarly journals The Influence of Lime Solution in Kneading Water Substitution on Cement Roughcast and Mortar Coating

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4174
Author(s):  
André M. Santos ◽  
Ângelo J. Costa e Silva ◽  
João M. F. Mota ◽  
João M. P. Q. Delgado ◽  
Fernando A. N. Silva ◽  
...  
Keyword(s):  
Bond Strength ◽  
Concrete Block ◽  
Tensile Bond Strength ◽  
Water Penetration ◽  
Strength Tests ◽  
Lime Solution ◽  
Concrete Blocks ◽  
Materials Used ◽  
Bonding Systems ◽  
Direct Tensile

The understanding of the mechanical fixation behavior of coatings is crucial for a better comprehension of the bonding systems, especially at the interface between the mortar and the substrate. Physical adherence is related, among other things, to the contents of the materials used in the roughcast and mortar coatings, due to the colloidal water penetration into the pores of the substrate. This work evaluated the influence of different lime solution additions replacing the kneading water in the preparation of roughcast and mortar coatings. Two types of substrates were investigated:ceramic bricks and concrete blocks. Three wall masonry panels were constructed, with dimensions of 220 × 180 cm2, one of concrete block and two of ceramic bricks, followed by the application of roughcast and mortar coating with an average thickness of 5 mm and 20 mm, respectively. Direct tensile bond strength tests were performed and the results, with a 95% confidence level, showed that substrate ceramic and treatment in the roughcast exhibited a better behavior regarding the distribution of the tensile bond strength of the tested specimens. However, no significant differences of the amount of addition used (0%, 5%, 10% and 15%) on the tensile bond strength were observed.

scholarly journals Four chemical methods of porcelain conditioning and their influence over bond strength and surface integrity

2015 ◽  
Vol 20 (4) ◽  
pp. 51-56 ◽  
Author(s):  
João Paulo Fragomeni Stella ◽  
Andrea Becker Oliveira ◽  
Lincoln Issamu Nojima ◽  
Mariana Marquezan
Keyword(s):  
Phosphoric Acid ◽  
Bond Strength ◽  
Surface Integrity ◽  
Hydrofluoric Acid ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Acid Etching ◽  
Ceramic Surface ◽  
Surface Conditioning ◽  
Phosphoric Acid Etching

OBJECTIVE: To assess four different chemical surface conditioning methods for ceramic material before bracket bonding, and their impact on shear bond strength and surface integrity at debonding.METHODS: Four experimental groups (n = 13) were set up according to the ceramic conditioning method: G1 = 37% phosphoric acid etching followed by silane application; G2 = 37% liquid phosphoric acid etching, no rinsing, followed by silane application; G3 = 10% hydrofluoric acid etching alone; and G4 = 10% hydrofluoric acid etching followed by silane application. After surface conditioning, metal brackets were bonded to porcelain by means of the Transbond XP system (3M Unitek). Samples were submitted to shear bond strength tests in a universal testing machine and the surfaces were later assessed with a microscope under 8 X magnification. ANOVA/Tukey tests were performed to establish the difference between groups (α= 5%).RESULTS: The highest shear bond strength values were found in groups G3 and G4 (22.01 ± 2.15 MPa and 22.83 ± 3.32 Mpa, respectively), followed by G1 (16.42 ± 3.61 MPa) and G2 (9.29 ± 1.95 MPa). As regards surface evaluation after bracket debonding, the use of liquid phosphoric acid followed by silane application (G2) produced the least damage to porcelain. When hydrofluoric acid and silane were applied, the risk of ceramic fracture increased.CONCLUSIONS: Acceptable levels of bond strength for clinical use were reached by all methods tested; however, liquid phosphoric acid etching followed by silane application (G2) resulted in the least damage to the ceramic surface.

scholarly journals Effect of Yd:YAG laser irradiation on the shear bond strength of orthodontic metal brackets

2020 ◽  
Vol 25 (1) ◽  
pp. 28-35
Author(s):  
Fernando César Moreira ◽  
Helder Baldi Jacob ◽  
Luis Geraldo Vaz ◽  
Antonio Carlos Guastaldi
Keyword(s):  
Bond Strength ◽  
Laser Irradiation ◽  
Shear Bond Strength ◽  
Surface Characterization ◽  
Test Machine ◽  
Base Surface ◽  
Bonding Failure ◽  
Significant Difference ◽  
Chi Square Analysis ◽  
Bracket Base

ABSTRACT Objective: The purpose of this study was to evaluate the effect of the Yd:YAG laser irradiation on orthodontic bracket base surface. Shear bond strength (SBS) values and sites of the bonding failure interfaces were quantified. Methods: Brackets were divided into two groups: OP (One Piece - integral sandblast base) and OPL (One Piece - laser irradiation). The brackets were randomly bonded on an intact enamel surface of 40 bovine incisors. The SBS tests were carry out using a universal test machine. A stereomicroscopy was used to evaluate the adhesive remnant index (ARI), and surface characterization was performed by scanning electron microscopy (SEM). Student’s t-test was used to compare the SBS between the two groups (p< 0.05). Frequencies and chi-square analysis were applied to evaluate the ARI scores. Results: OPL group showed higher value (p< 0.001) of SBS than OP group (43.95 MPa and 34.81 MPa, respectively). ARI showed significant difference (p< 0.001) between OPL group (ARI 0 = 100%) and OP group (ARI 0 = 15%). SEM showed a higher affinity between the adhesive and the irradiated laser base surface. Conclusions: Yd:YAG laser irradiation on bracket base increased SBS values, showing that bonding failure occurs at the enamel/adhesive interface. Laser-etched bracket base may be used instead of conventional bases in cases where higher adhesion is required, reducing bracket-bonding failure.

An Improved Cross-Bonded Method for Measuring Interfacial Bond Strength of Adhesives

2017 ◽  
Vol 726 ◽  
pp. 8-12
Author(s):  
De Long Ma ◽  
Yi Wang Bao
Keyword(s):  
Mechanical Properties ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Original Method ◽  
Interfacial Shear ◽  
Interfacial Bond ◽  
Interfacial Bond Strength ◽  
True Value ◽  
Bonded Method ◽  
Method Show

Interfacial bond strength is one of the vital mechanical properties of adhesives. The cross-bonded method, which is widely used to measure the interfacial tensile and shear bond strength simultaneously, has attracted extensive attention. An improved cross-bonded method is presented in this study in order to promote the accuracy and reliability of the testing results. The ergo 9900 glue, E-7 glue, AB glue and 502 glue were measured in this study. Compared with the original method, the results of the improved cross-bonded method show that: (i) the coefficient of variation of the interfacial bond strength decreased significantly; (ii) the interfacial shear bond strength of the adhesives is closer to its true value.

Effects of aging on shear bond strength to dentin and mechanical properties of restorative glass ionomer cements

2020 ◽  
Vol 102 ◽  
pp. 102693
Author(s):  
Adriana P. Manso ◽  
Kunal Chander ◽  
Karen M. Campbell ◽  
Regina G. Palma-Dibb ◽  
Ricardo M. Carvalho
Keyword(s):  
Mechanical Properties ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Effects Of Aging

Influence of the Mineralogical and Mortar Components on the Adherence of Some “Granites”

2013 ◽  
Vol 548 ◽  
pp. 267-274 ◽  
Author(s):  
Lizandra Nogami ◽  
Antenor B. Paraguassú ◽  
José E. Rodrigues ◽  
Rogério P. Ribeiro
Keyword(s):  
Bond Strength ◽  
Single Crystals ◽  
Rough Surface ◽  
Tensile Bond Strength ◽  
Polished Surface ◽  
Optical Orientation ◽  
Adhesion Bond ◽  
Strength Tests ◽  
Mineral Components ◽  
Traction Test

Rock plate setting can be performed with metal inserts or by mortar adhesion. For mortar setting, the adhesion bond strength values, as a rule, should be above 1 MPa. In the present work, tests with eight types of “granite” tiles were performed to compare the adherence of five types of mortars. The rocks chosen were: Red Brasilia (syenogranite), Black Indian (migmatite), Green Labrador (charnockite), Black Sao Gabriel (hypersthene diorite), Rose Jacaranda (nebulitic migmatite syenogranite), Fantastic Blue (biotite monzogranite megaporphyritic serial gneissified), Grey Swallow (monzogranite) and Yellow Ornamental (garnet porphyroblastic gneiss), which do not have similar petrographic and sawability characteristics, thereby resulting in different initial roughness values of the plates obtained by breaking apart the blocks on the gangsaw machine, which use granulated steel as an abrasive element. The adherence of these rocks with the mortars was determined in the rough surface as well as in the polished surface by the pullout traction test, standardized for ceramics. The results showed that the mortar adhesion is related to roughness, to mineralogy and to the texture of these rocks. To verify this relationship, tensile bond strength tests were performed with the main mineral components of these rocks using single crystals with known optical orientation. Moreover, the microstructure study of the standard substrate/mortar/rock set was also performed.

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