pps proceeding - Abstract Preview
pps proceeding
Symposium: S20 - Microtribology and Surface Analysis
Oral Presentation
 
 

Wear, micro surface deformation and visco-elastic properties of dental composits.

Geis-Gerstorfer Jürgen (1)*, Schille Christine (1)

(1) University of Tübingen - BW - Germany

Objective: Dental structures are subjected to masticatory stresses and the fluids of the oral environment. For forecasting of wear of dental composite restorations, based on visco-elastic material properties, correlation studies are required. Materials and Methods: One direct light-activated (Arabesk Top) and two indirect light-activated dental composite materials (Artglass, Sinfony) were investigated before and after immersion for 3 month in water, ethanol, lactic acid, NaOH and PCE. (a) Wear: In order to imitate clinical wear conditions a chewing simulator (Willitec, Germany; load 50 N, 10E6 cycles) and a steatite ball as antagonist was used. (b) Microtribology: The micro-mechanical deformation of the composite surfaces was analysed using a universal surface tester (UST, Innowep, Germany). Standard tests according to the MISTAN principle (90° diamond tip, 50 mN) as well as micro wear tests (stepwise increasing loadings 12 mN; range 1-100 mN) were applied. (c) DMA: For the investigation of the visco-elastic bulk properties dynamic mechanical analysis was used (DMA Q800, TA Instruments, USA). Controlled strain temperature step/frequency and temperature sweep experiments were performed. Results: Wear volume was influenced by the moist environment and was lowest in water (Arabesk 0.20, Artglass 0.09, Sinfony 0.08 mm³) and highest in PCE (Arabesk 0.48, Artglass 0.35, Sinfony 0.24 mm³). In ethanol, the micro-tribological induced permanent surface deformation varied between 1.41 µm (Arabesk), 1.32 µm (Artglass) and 1.05 µm (Sinfony). A similar ranking was found with the loss modulus G'' (Arabesk 842, Artglass 596, Sinfony 420 MPa). Conclusion: With the methodical combination of wear (artificial ageing), micro surface deformation (elastic/permanent portions) and dynamic mechanical analysis (visco-elastic properties) a correlation of dental composite materials properties could be found.