Two- and three-body wear of composite resins
ABSTRACT The aim of the present study was to investigate two- and three-body wear of microfilled, micro-hybrid and nano-hybrid composite resins using a ball-on-disc sliding device.
One microfilled (Durafill VS), one micro-hybrid (Filtek Z250), one hybrid (Clearfil AP-X), one nanofilled (Filtek Supreme XT), and two nano-hybrid (MI Flow, Venus Diamond) composite resins were examined. The composites were filled in a cylindrical cavity, and light polymerized. After storage in 37°C distilled water for 7days, all specimens were tested with a custom-made ball-on-disc sliding device with a zirconia ball as antagonist (50N loads, 1.2Hz, 10,000 cycles) immersed in water, poppy seed slurry and polymethyl methacrylate slurry, respectively. Maximum wear depth and volume loss of worn surfaces were quantified by a digital CCD microscope and analyzed with two-way analysis of variance.
The interactions between composite resin and condition of their maximum wear depth and volume loss were significant (p<0.01). The abrasive wear produced at three-body loading with poppy seed slurry was very large for the microfilled composite, and small for all other composites tested. In contrast, two-body wear of the microfilled composite, and one nano-hybrid composite was very low.
The ball-on-disc sliding device used is considered suitable to simulate sliding of an antagonist cusp on an opposing occlusal composite restoration, either in the two- or the three-body wear mode. All tested materials except for the microfilled composite showed low surface wear when exposed to poppy seed as the third-body medium.
SourceAvailable from: Magdalena Osiewicz[Show abstract] [Hide abstract]
ABSTRACT: Nowadays direct and indirect resin composites are frequently applied to build up the occlusion when extensive tooth wear took place. To achieve long-lasting restorations it is essential to obtain knowledge about their interactions due to occlusal contacts. Therefore, the two- and three-body wear between frequently used direct and indirect resin composites was investigated. The two- and three-body wear of three direct resin composites and three indirect resin composites, with Clearfil AP-X, Filtek Z250, and Filtek Supreme XT as antagonists, were measured, using the ACTA wear device. The wear rates were determined and the surfaces were evaluated with SEM. The most remarkable outcome was that the two-body wear rate of the different composites opposing the Z250 wheel were significantly higher. Furthermore, it was shown that the three-body wear rate was independent on the antagonist and in general higher than the two-body wear rate. To reduce abrasion of the opposing resin composite surface the resin composite fillers should consist of a softer glass, e.g. barium glass or in case of a harder filler the size should be reduced to nano-size. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.Dental Materials 12/2014; DOI:10.1016/j.dental.2014.11.007 · 4.16 Impact Factor
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ABSTRACT: To evaluate the effects of toothbrushing abrasion associated with pH cycling on the surface roughness and wear of methacrylate- and silorane-based resin composites. Microhybrid methacrylate-based (Filtek Z250), nanofilled methacrylate-based (Filtek Supreme Ultra) and microhybrid silorane-based (Filtek LS) composites were selected for this investigation. For each composite, two groups (n = 10) of rectangular specimens were made. The initial roughness (Ra) of all of the groups was evaluated based on the average of three random tracings with a profilometer, and each specimen had half of its surface protected with two layers of nail varnish to serve as controls. Half of the specimens of each resin were submitted to pH cycling, while the other half were stored in deionized water for 14 days. Subsequently, 100,000 strokes of simulated toothbrushing were performed. Final roughness and wear were measured with the same profilometer, and the values were submitted to ANOVA, Student's t-test and Tukey's test (P < 0.05). The data revealed an increase in surface roughness for Filtek Z250 and Filtek Supreme Ultra after toothbrushing, while Filtek LS showed the opposite behavior. Methacrylate-based composites presented lower wear values [Z250 (4.19 ± 1.73 μm); Supreme Ultra (4.16 ± 0.95 μm)], while the silorane-based composite presented increased surface roughness (11.51 ± 5.69 μm), particularly when submitted to pH cycling (15.31 ± 5.41 μm). Despite the good properties of silorane-based composites, particularly its smooth surface roughness even after pH cycling and toothbrushing abrasion, this composite still presented increased wear, which is an important issue for the development of new resin compositions.American journal of dentistry 08/2014; 27(4):195-8. · 1.06 Impact Factor
Conference Paper: Evaluation of Mechanical and Esthetic Properties of Orthodontic Sealants[Show abstract] [Hide abstract]
ABSTRACT: Development of white spot lesions during orthodontic treatment is an ever increasing problem for orthodontic patients. These lesions on tooth surfaces are not only an esthetic concern at the end of orthodontic treatment but also a risk factor for development of cavitated lesions. Orthodontic sealants could provide surface protection during fixed appliance therapy to avoid the development of WSL. Objective: Compare the clinically relevant mechanical properties of two commercially available orthodontic sealants: Opal®Seal (OS) and L.E.D. ProSeal (PS). The primary difference between these sealants is filler content. Mechanical stability and esthetics of sealants are dependent on material hardness, wear resistance and color stability. Adequate mechanical stability of the sealant is essential for it to remain on the enamel surface to render protection throughout the mechanotherapy. Method: Ten discs of 2 mm thickness and 12 mm in diameter of each sealant type were prepared and tested for following properties: Micro hardness using the Knoop hardness test, wear resistance using a profilometer. Fifteen discs of 2 mm thickness and 25 mm in diameter of each sealant type were used for color stability using colorimetry for wine, coffee and water. Result: OS was significantly harder than PS (p<0.001). PS was significantly more wear resistant than OS (p<0.05). PS showed a greater DE*ab (increased staining) when placed in wine or coffee showing a significant difference (p < 0.05). Conclusion: Both orthodontic sealants are potentially beneficial for protecting enamel. However with improved wear properties, PS was superior in resisting mechanical stresses. OS was more resistant to color changes. Currently studies are being conducted to test the resistance of enamel to demineralization using PTR-LUM (Canary System™).IADR General Session and Exhibition 2014; 06/2014