GC EUROPE Kalore - Manual (Page 36)

36
7mm
2mm
GC Kalore technical manual
3. combined polish retention/surface roughness test
composite samples were prepared in an acrylic mold
and their surfaces polished using sandpaper with #80,
#180, #320, #600, #1000, #1500 and #2000 grits,
followed by final polishing with a buff and 1µm
alumina. after measuring the surface gloss rates, the
samples were moved up and down along a 4 cm path
at a rate of 30 strokes per minute and held in indirect
contact with an acrylic plate under a load of 350 gf
load. Simultaneously, the sample holder was moved
horizontally along a 2 cm path at a rate of 30 strokes
per minute. A mixture of PMMA and glycerol (1:1
volume) was used as an intermediate abrasive. after
100,000 cycles (one complete lateral and vertical
movement counts as one cycle, and 100,000 cycles is
equivalent to between two and ten years of wear), the
surface gloss was measured. Subsequently, samples
of the composites were processed for SEM imaging.
in addition, composite samples were scanned using
confocal laser microscopy (CLSM) to assess surface
roughness (Ra) before and after the polish retention
test.
Results and Discussion
Results of the shrinkage stress, wear property, polish
retention and surface roughness measurements are
shown in table 2.
Table 2. Shrinkage stress, wear and surface gloss test results.
Shrinkage Stress Results
The shrinkage stress of KALORE measured 8.3N, which was 12% less than the shrinkage stress of
KALORE without DuPont which was 9.5N. This test confirmed that incorporation of the new low
shrinkage monomer (DX-511) reduces shrinkage stress.
Figure 3. combined polish retention/surface roughness test set-up.
KalORe KalORe without DuPont
Shrinkage Stress (N) 8.3 9.5
Wear Test (μm) 15.9 (2.3) 16.3 (5.9)
Gloss Retention
(Gloss Rate) (%)
after Polish 80.1 (4.2) 76.0 (4.5)
after stress 78.2 (4.8) 70.4 (4.1)
Surface Roughness
(Ra) (μm)
after Polish 0.019 (0.001) 0.047 (0.008)
after stress 0.027 (0.004) 0.059 (0.011)
PMMA/glycerol slurry
350 gf load