scholarly journals Effect of Thermocycling on Surface Roughness and Shear Bond Strength of Acrylic Soft Liner to the Surface of Thermoplastic Acrylic Treated with Ethyl Acetate

2018 ◽  
Vol 11 (3) ◽  
pp. 1491-1500
Author(s):  
Wedyan Yaseen Hasan ◽  
Mohammed Moudhaffar Ali

This study aimed to assess the effect of halloysite nanotubes(HNTS) addition into soft denture lining material on thermal conductivity and thermal diffusivity, shear bond strength, tear strength, and surface roughness of the lining material. HNTS with 0.75% and 1% concentration by weight (according to the pilot study) were added into acrylic-based heat cured soft denture liner. One hundred and twenty different specimens were prepared and divided into four groups according to the test to be performed. The thermal conductivity and thermal diffusivity of the soft liner/ HNTS composite were evaluated, shear bond strength, tear strength, and surface roughness were also measured, the results showed that there was a highly significant increase in thermal conductivity of the experimental specimens in comparison with the control specimens and a non-significant change in the thermal diffusivity of the experimental specimens. The shear bond strength between the soft liner and the acrylic denture base and tear strength showed a highly significant increase, but a non- significant difference in the surface roughness test was observed in all experimental specimens. Thus it can be concluded that the addition of HNTS can provide soft liner material with improved thermal conductivity, shear bond strength and tear strength while thermal diffusivity and surface roughness were non-significantly changed when the concentration of HNTs nanoparticles increased.


2017 ◽  
Vol 751 ◽  
pp. 131-136
Author(s):  
Danuwat Pupan ◽  
Chakrit Suvanjumrat ◽  
Watcharapong Chookaew

Brake pad is the combination of lining and metallic components, e.g. steel backing plate (disc brake) and aluminum brake shoe (drum brake). Shear bond strength plays a major role to provide the safety and/or drive performances. This work aimed to study the processing factors affected the bonding strength. The molding temperature couple with post-curing temperature was simultaneously analyzed in order to optimize the processing temperature. The shear bond strengths of metallic plates were continually investigated with regard to the effect of different surface treatments. The obtained results indicated that the mechanical strength was increased as the molding temperature raised in ranges of 160°C to 180°C. Conversely, the deterioration of adhesive strength was progressively presented with rising post curing temperature. In comparing different backing plate, aluminum showed the higher shear bond strength than that of steel plate. In fact, the weakened property of aluminum in nature would be easily destroyed by mechanical treatments. From the shear tested results, an increase of surface roughness was inversely changed the shear bond strength. On the other hand, the contact angle of water droplet affected directly to adhesive strength. It was suggested that an adding surface roughness, commonly used in automotive industry, was inappropriate criteria, whist geometrical surface should be taken into account for improving the shear bond strength. Moreover, the contact angle and mechanical interlocking were recommended to use as a criteria of brake pad shear strength.


2014 ◽  
Vol 33 (6) ◽  
pp. 778-785 ◽  
Author(s):  
Min HE ◽  
Zutai ZHANG ◽  
Dongxiang ZHENG ◽  
Ning DING ◽  
Yan LIU

1990 ◽  
Vol 6 (3) ◽  
pp. 204-207 ◽  
Author(s):  
P.M. McInnes ◽  
S.L. Wendt ◽  
D.H. Retief ◽  
R. Weinberg

2021 ◽  
Vol 12 ◽  
pp. e2-e2
Author(s):  
Abdulsatar M Abdulsatar ◽  
Basima M A Hussein ◽  
Ali M Mahmood

Introduction: This study was performed to compare the effect of Fractional CO2 laser or Q switched Nd:YAG laser of surface treatment on the shear bond strength of zirconia-porcelain interface. Methods: Fractional CO2 laser at 30 W, 2 ms, time interval 1 ms, distance between spots 0.3 mm, and number of scans is (4) or Q switched Nd:YAG laser at 30 J/mm2 and 10 Hz were used to assess the shear bond strength of zirconia to porcelain. Pre-sintered zirconia specimens were divided into three groups (n = 10) according to the surface treatment technique used: (a) untreated (Control) group; (b) CO2 group; (c) Nd:YAG group. All samples were then sintered and veneered with porcelain according to the manufacturer’s instructions. Surface morphology was examined using a light microscope, the surface roughness test was done by the atomic force microscope (AFM), and the shear bond strength (SBS) test was done by a universal testing machine. After debonding following shear bond test, zirconia surfaces were examined under a light microscope to determine their fracture mode. Results: The Results of this study showed that the lowest SBS was recorded in the control group, and the highest SBS recorded in the Fractional CO2 group, followed by the Q switched Nd:YAG laser group, as well as an increase in surface roughness and change in the morphology and mode of failure in the experimental groups . Conclusion: This study shows that Fractional CO2 laser and Q switched Nd:YAG laser treatments significantly increase the bond strength than untreated zirconia .


2018 ◽  
Vol 11 (3) ◽  
pp. 1573-1581 ◽  
Author(s):  
Maha M. Turki ◽  
Faiza M. Abdul-Ameer

Scleral acrylic resin is widely used to synthesize ocular prosthesis. However, the properties of this material change over time, thus requiring the prosthesis to be refabricated. Many studies were conducted to improve these properties by reinforcing this material with nanoparticles. This study aims to evaluate the effect of silver nanoparticle powder on the mechanical properties (transverse flexural strength, impact strength, shear bond strength, surface microhardness, and surface roughness) of scleral acrylic resin used for ocular prostheses. Two concentrations were selected from the pilot study and evaluated for their effects on scleral acrylic resin properties. According to the pilot study, 0.01 and 0.02wt% AgNPs powder improved the transverse flexural strength, microhardness, and surface roughness compared with other percentages. The specimens in the main study were divided into (3) main groups, (50) specimens without additives (control group A), (50) experimental specimens (with 0.01wt% AgNPs group B), and (50) experimental specimens (with 0.02 wt% AgNPs group C). Each group was subdivided into (5) equal subgroups depending on the tests used. The data were studied using one way ANOVA and post hoc LSD test. At 0.01 wt% AgNPs addition, the mean values of transverse flexural strength insignificantly increased (p> 0.05), and those of impact strength and shear bond strength significantly increased (p< 0.05) compared with those of the control group. At 0.02 wt% AgNPs addition (group C), the mean value of transverse flexural strength significantly increased (p< 0.05), that of impact strength insignificantly increased (p> 0.05), and that of shear bond strength increased with high significance (p< 0.01) compared with those of the control group. Group C showed insignificant increase in the mean values of transverse flexural strength, impact strength, and shear bond strength (p. 0.05) compared with group B. The scleral acrylic resin added with 0.01 and 0.02 wt% AgNPs showed insignificant increase in microhardness and insignificant decrease in surface roughness. The addition of AgNPs powder in both concentrations improved the mechanical properties of scleral acrylic resin used for ocular prostheses.


1999 ◽  
Vol 107 (5) ◽  
pp. 400-413 ◽  
Author(s):  
Pierluigi Coli ◽  
Simon Alaeddin ◽  
Ann Wennerberg ◽  
Stig Karlsson

2012 ◽  
Vol 512-515 ◽  
pp. 1765-1769 ◽  
Author(s):  
Chen Hu ◽  
Long Quan Shao ◽  
Yuan Fu Yi ◽  
Qi Liu ◽  
Bin Deng ◽  
...  

Despite the expanded application for zirconia in restoration dentistry, there is less clear recommendation in the literature regarding the relation between zirconia surface roughness and its shear bond strength to resin cements. The aim of this study was to assess the effect of surface roughness of Cercon zirconia on its shear bond strength to resin cements. 66 Zirconia rectangular specimens (10 mm×10 mm×3 mm) were prepared from Cercon zirconia blocks, finished using a diamond rotary cutting instrument, sintered, and then assigned into 6 groups. The specimens in the first group without polishing were used as control. Other groups were polished against 120#, 240#, 360#, 500# and 600# sand paper after sintered, respectively. Ceramic surface were analyzed by scanning electron microscopy (SEM) and Surface profilometer. 10 samples of each group were bonded with Variolink N resin cements respectively and submitted to shear bond strength test. Shear bond strength was measured and statistically analyzed. The results showed that the population means of 6 groups of samples were not equal. There was no significant difference between control group and 600# sand paper treated group, 500#, 360# and 240# sand paper treated groups (P>0.05), but a significant difference among the other groups (P<0.05). Findings of this study revealed that the shear bond strength might be raised by increasing the surface roughness of Cercon zirconia. Therefore, the surface roughness of Cercon zirconia has an effect on the shear bond strength, but is not the determining factor in clinical use.


2007 ◽  
Vol 77 (4) ◽  
pp. 723-728 ◽  
Author(s):  
YŞinasi Saraç ◽  
Selma Elekdag-Turk ◽  
Duygu Saraç ◽  
Tamer Turk

Abstract Objective: To investigate the effects of three surface conditioning methods on shear bond strength (SBS) and on surface roughness (Ra) of a feldspathic ceramic, and to compare the efficiency of three polishing techniques. Materials and Methods: A total of 106 feldspathic specimens were used. Thirty specimens were divided into three groups according to the surface conditioning methods: air-particle abrasion (APA) with 25-μm aluminum trioxide (Al2O3) (group A); hydrofluoric acid (HFA) (group H); APA and HFA (group AH). Metal brackets were bonded and subjected to SBS testing. Sixty-three specimens were divided into three groups according to the surface conditioning method. Ra was evaluated profilometrically. Then, each group was divided into three subgroups according to the polishing technique, ie, adjustment kit, diamond polishing paste, adjustment kit + diamond polishing paste. Following polishing, the second Ra values were obtained. Results: The lowest SBS was obtained for group H. This value was significantly different from the values of groups A and AH (P &lt; .05). The lowest Ra value was observed for group H (P &lt; .001). There was no significant difference between groups A and AH (P &gt; .05). No significant differences between the subgroups in which a polishing paste was used were observed (P &gt; .05). There was no significant difference between the adjustment kit and the adjustment kit + a diamond polishing paste (P &gt; .05). Conclusion: APA or APA + HFA created rougher porcelain surfaces than HFA alone. Both adjustment kit use and the adjustment kit + polishing paste application were effective to smooth the porcelain, but one was not found superior to the other.


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