1253 New method for a complex characterization of materials mechanical behavior
N. ILIE, K.-H. KUNZELMANN, K. FELTEN, D. MARKOVICx, and R. HICKEL, Dental school of the LMU, Munich, Germany, Germany

Objectives:

For the application-oriented evaluation of the mechanical behavior of restorative materials, meaningful and reliable characteristics are needed. To evaluate the quality of polymerization of hardness measurement is a very useful indirect measure of polymerization as long as the same material is considered. One disadvantage of hardness measurements of composites is that it is very complicated to evaluate the indenter impression visually.

Methods:

The aim of the study was to evaluate the measuring-method of Universal Hardness (HU) on dental composites. The advantage of the automatical HU measurement versus the optical HV-measurement is the absence of subjective influences. In addition the test load ranges from 0.4 mN to 1000 mN. The load and the penetration depth of the indenter are continuously measured during the load-unload-hysteresis. With only one measurement, besides the surface hardness elastic and plastic characteristics, creep and relaxation behaviours of a material would be available as well. Within the scope of this presentation hardness was the only parameter presented here. The new material InTen S (Vivadent) was evaluated with several curing regimes (Freelight (FL), e-Light (EL), Easy cure(EC)).. The measurements were made with the micro hardness indenter Fischerscop H100C (Fischer, Germany).

Results:

Lamp / DepthSurface1mm2mm3mm4mm5mm
FL standard348.9 (6.7)339.5 (10.9)335.3 (6.3)296.1 (6.7)205.6 (6.7)139.3 (6.3)
FL exp.360.4 (6.7)330.3 (9.7)322.7 (9.7)260.8 (6.7)151.8 (10.7)78.5 (7.4)
GC, soft cure382.8 (13.9)328.2 (6.7)302.9 (9.5)253.8 (6.7)141.7 (5.7)77.4 (6.7)
GC, Pulse342.6 (6.8)256.3 (6.5)226.8 (8.7)211.0 (6.7)199.8 (6.3)64.2 (8.7)
GC, fast cure356.0 (8.8)351.1 (6.7)237.2 (6.3)141.5 (6.7)81.5 (9.7)-
Easy cure351.9 (6.8)338.8 (9.9)228.8 (5.6)171.1 (6.7)110.9 (6.2)77.3 (5.4)

Conclusions:

At a depth of 2 mm all curing devices were better that the 80 % cut-off value compared with the best curing regime which is usually considered as insufficient cure of the material. At a depth of 3 mm only FL standard, FL exp. and GC, soft cure achieved a acceptable performance.

Seq #123 - Properties of Polymers and Tooth Structure
3:45 PM-5:00 PM, Thursday, 7 March 2002 San Diego Convention Center Exhibit Hall C

Back to the Dental Materials: VIII - Others-Non-metallic Program
Back to the IADR/AADR/CADR 80th General Session (March 6-9, 2002)

Top Level Search