Statement Of Problem: By decreasing the proportion of filler, flowable composites are easy to adapt to small cavity preparations. However, the wear resistance of flowable composites is a clinical concern, as improved wear has been related to increased filler percentage.
Purpose: The purpose of this study was to compare wear for flowable composites and comparable heavily filled materials.
Material And Methods: Wear by attrition and abrasion (microm) of microfilled flowable (Heliomolar Flow) and heavily filled microfill (Heliomolar HB) was measured and compared to a microhybrid flowable (Tetric Flow) and a heavily filled microhybrid (Tetric HB). There were 5 specimens, 2 mm thick and 15 mm in diameter, in each group. The Oregon Health Sciences University oral wear simulator was used to produce abrasive wear and attrition for all specimens. Abrasion and attrition of the substrates were measured using a profilometer. Data were subjected to a 3-way analysis of variance for the 3 main factors: composite type, filler load, and wear type (alpha=.05)
Results: Composite wear rates were significantly influenced (P <.01) by both the type of wear and the filler amount. Abrasive wear occurred less than wear by attrition, and the heavily filled composites experienced less wear than the flowable composites.
Conclusions: Results of this in vitro study suggest that highly filled microhybrid composites may have greater wear resistance for contact-supporting posterior restorations. However, in small noncontact restorations where longevity may be dictated by abrasion, flowable microfilled resins may be adequate.
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http://dx.doi.org/10.1016/j.prosdent.2004.11.006 | DOI Listing |
Materials (Basel)
December 2024
Faculty of Architecture and Civil Engineering, TU Dortmund University, 44227 Dortmund, Germany.
Industrial and construction wastes make up about half of all world wastes. In order to reduce their negative impact on the environment, it is possible to use part of them for concrete production. Using experimental-statistical modeling techniques, the combined effect of brick powder, recycling sand, and alkaline activator on fresh and hardened properties of self-compacting concrete for the production of textile-reinforced concrete was investigated.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Faculty of Mechanical Engineering, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland.
In the first part of this publication, selected technological and strength properties of synthetic molding sand bound with sodium bentonite with the addition of a new lustrous carbon carrier (R, R, R, W, P, Z, P, P, S, ρ) were determined. The introduction of polyethylene as a substitute for hydrocarbon resin, and shungite as a replacement for coal dust, demonstrated the achievement of an optimal molding sand composition for practical use in casting technology. The sand containing a new lustrous carbon carrier (SH/PE) demonstrates the highest permeability and flowability.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Energy School, Xi'an University of Science and Technology, Xi'an 710054, China.
Fly ash-cement composite backfill slurry, prepared by partially replacing cement with fly ash, has been demonstrated to effectively reduce the mine backfill costs and carbon emissions associated with cement production. However, the use of fly ash often results in insufficient early and medium-term strength of the backfill material. To address the demand for high medium-term strength in backfill materials under continuous mining and backfilling conditions, this study developed a silica fume-fly ash-cement composite backfill slurry.
View Article and Find Full Text PDFBMC Oral Health
January 2025
Department of Endodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
Background: The fracture of an endodontic instrument within the root canal system can occur during root canal therapy, complicating thorough cleaning and shaping. Consequently, managing the broken fragment becomes crucial.
Methods: Eighty Nickel-titanium (NiTi) #20 K-files (Mani, Tochigi, Japan) were cut 8 mm from the tip, fixed into a corkboard, and classified into five groups (n = 14 each).
JADA Found Sci
April 2024
Division of Biomaterial and Biomedical Sciences, Oregon Health & Science University, Portland, OR.
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