Characterization of contemporary resin cements
Date
2013
DOI
Authors
Binmahfooz, Abdulelah Mahfooz
Version
OA Version
Citation
Abstract
Objectives: To evaluate the mechanical and physical properties of new self-etching (SE) and conventional resin cements with different mixing and polymerization methods, and to evaluate the effect of glow discharge (GD) plasma surface treatment on bonding cements to Zirconia.
Materials and methods: The tested cements studied were, Biscem (Bisco), Ceramir C&B (Doxa), Embrace Wetbond (Pulpdent), G-CEM (GC), Ketac-Cem (3M ESPE), Maxcem (Kerr), Monocem (Shofu), Multilink Automix (Ivoclar), Multilink Sprint (Ivoclar), Panavia F2.0 (Kuraray), RelyX Unicem (3M ESPE), RelyX Unicem 2 (3M ESPE), RelyX Ultimate (3M ESPE). RelyX ARC (3M ESPE), a conventional resin cement served as a control. For compressive strength, 20 cylinder-shaped cement speciimens (4 mm diameter x 6 mm height) were made for autocure (n=10) and photocure (n=10). For flexural strength and elastic modulus, 20 bars measuring 2 mm h x 2 mm w x 25 mm l were made for autocure (n=10) and photocure (n=10). The freshly mixed cements were placed in Teflon molds in the specified dimensions. A Triad 2000 machine (Dentsply, York Division, USA) was used for polymerization for 1 minute on each side. For the film thickness (n=5), the mixed cement (0.1 gm) was placed between 2 pre-cleaned microscopic slides and then placed between 2 flat square glass plates of uniform thickness. After each manufacturer’s recommended mixing time had elapsed, a load of 15 kg was applied vertically to the plates for 10 minutes. An electronic gauge (Digimatic Micrometer, Mitutoyo MGF. Co.) was used for measurement to the nearest micron. For the separation force test, custom-made zirconia rings measuring 12.5±0.1 mm in outer diameter, 5.5[plus or minus]0.1 mm in height and 5.9[plus or minus]0.1 mm in inner diameter (n=200) were made. Cylindrical shaped titanium rods (n=200) were machined with a uniform diameter of 5.9[plus or minus]0.01 mm and a 12 mm height. Half the specimens received glow discharge treatment for 2 minutes using a high frequency voltage, Plastic chamber and a vacuum pump. Half of these specimens were additionally thermocycled for 1500 cycles in water baths held at 5 degrees C and 55 degrees C, with a dwell time in each bath of 30 seconds and a transfer time of 15 seconds. Specimens were stored in water at 37 degrees C for 24 hours prior to testing. Specimens were tested using an Instron universal testing machine (cross-head speed of 0.5 mm/min) for their respective test. The data were analyzed by using Student's t-test, 1-way ANOVA and linear regression analyses.
Results: Compressive strength: In the auto-mix group, the mean autocure compressive strength data ranged from 185 MPa (RelyX Unicem) to 309 MPa (Multilink Automix), while the mean for the photocure group data ranged from 194 MPa (Multilink Sprint) to 306 MPa (Multilink Automix). In the hand-mix group, the mean autocure compressive strength data ranged from 198 MPa (Biscem) to 253 MPa (Panavia F2.0), while the mean for the photocure group data ranged from 198 MPa (Biscem) to 261 MPa (RelyX ARC). Flexural strength: In the auto-mix group, the mean autocure flexural strength data ranged from 42 MPa Embrace Wetbond) to 101 MPa (Multilink Automix), while the mean for the photocure group data ranged from 75 MPa (Monocem) to 117 MPa (Multilink Automix). In the hand-mix group, the mean autocure flexural strength data ranged from 69 MPa (Biscem) to 104 MPa (RelyX ARC), while the mean for the photocure group data ranged from 80 MPa (Biscem) to 121 MPa (RelyX ARC). Elastic modulus: In the auto-mix group,the mean autocure elastic modulus data ranged from 0.9 GPa Embrace Wetbond) to 5.5 GPa (RelyX Unicem), while the mean for the photocure group data ranged from 2 GPa (Monocem) to 7.7 GPa (G-CEM). In the hand-mix group,the autocure mean elastic modulus data ranged from 3.6 GPa (Biscem) to 7.2 GPa (Panavia F2.0), while the mean for the photocure group data ranged from 6.3 GPa (Biscem) to 7.7 GPa (Panavia F2.0). Film thickness: The mean film thickeness of the resin cements ranged from 14[mu]m (Monocem) to 24 [mu]m (G-CEM). Separation force: In the no-glow discharge group,the mean separation force ranged from 211 N (Ketac-Cem) to 1423 N (RelyX Ultimate), while the glow discharge group mean ranged from 304 N (Ketac-Cem) to 1821 N (RelyX Ultimate). In the no-glow discharge with themocycling group the mean separation force ranged from 249 N (Ketac-Cem) to 1782 N (RelyX Ultimate), while the mean for the glow discharge with thermocycling group ranged from 301 N (Ketac-Cem) to 1729 N (RelyX Ultimate).
Conclusions: There was a large variance in mechanical properties among the self-etching resin cements tested p[less than] 0.01). Photocuring produced significantly higher mechanical properties when compared with autocuring ([less than] 0.01). Mixing method (hand-mix vs. auto-mix) had no significant effect on mechanical properties. There was a significant diffence in film thickness among the cements tested, but all were within ADA accepted limits. GIow discharge treatment of zirconia rings made a significant difference in separation force (p [less than] 0.01) for most cements tested. Thermocycling did not show any significant difference (p[greater than] 0.01) on the retention of zirconia to titanium rods. Regression analysis indicated that both cement type, and glow discharge treatment were statistically significant factors affecting mean separation force (p[less than] 0.01).
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Thesis (DScD) --Boston University, Henry M. Goldman School of Dental Medicine, 2013 (Department of Restorative Sciences and Biomaterials)
Includes bibliographic references: leaves 121-129.
Thesis (DScD) --Boston University, Henry M. Goldman School of Dental Medicine, 2013 (Department of Restorative Sciences and Biomaterials)
Includes bibliographic references: leaves 121-129.
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This work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.