GC EUROPE Kalore - Manual (Page 17)

17 GC Kalore technical manual
Before each stress measurement, two pieces of quartz rod (6 mm in diameter) were flattened and
polished with 600 grit wet silicon carbide paper, and two layers of silanation were applied to one
end of each rod. the upper rod was mounted with the silanated end pointing down. then the
bottom quartz rod was aligned vertically to the upper rod and mounted with the silanated end
pointing up. The distance between the two silanated ends was fixed at 2.25 mm for all samples.
Thus, each composite sample was a disk 6 mm in diameter and 2.25 mm in height corresponding
to a C-factor of 1.33 (diameter/2x height). A polytetrafluorethylene (PTFE) sleeve was placed
around the gap between the two rods to keep the composite sample in place. two holes were
created on opposite sides of the sleeve, with the first hole (1.5 mm in diameter) used to inject the
composite and the second one (0.5 mm in diameter) used as a vent during sample injection.
under ambient yellow light, composite was injected into the sample holder to fill the space
between the silanated ends (n=5). The composite was light-cured for 60 seconds through the
bottom quartz rod with an elipar highlight curing unit. the light intensity at the end of the quartz
rods was measured at >600 mW/cm2 and were checked between groups. if the intensity had
changed, the lamp was replaced. Polymerization contraction stress kinetics was measured every
second for 30 minutes from the initiation of light-curing. contraction stress was determined by
dividing the measured tensile force by the cross-sectional area of the sample. Maximum stress rates
were determined by taking the first derivative of the stress vs. time curve. the gel point was
identified as the first data point with a significant non-zero slope. the data was analyzed statistically
using the one-way anOVa test.
It was found that both the contraction stress and the maximum stress rate were lower for KALORE
than for all other composites tested (Table 4). The measured levels of stress should enhance the
ability of KALORE to form intact dental adhesive interfaces. Furthermore, the lower rate of
acquiring the contraction stress should also contribute to an improved stress environment for
the interface.
Table 4. Contraction stress, maximum stress rate and gel point.
all superscript letters indicate statistically similar groups (p<0.001 for contraction stress and p<0.01 for all other groups).
Contraction Stress
(mPa)
Max Stress Rate
(mPa)
Gel Point
(mins)
KalORe 1.72 ± 0.10a 2.80 ± 0.71a 0.13 ± 0.02a
Filtek Supreme Plus† 2.61 ± 0.19b 5.62 ± 0.99b,c 0.13 ± 0.01a
esthetX hD† 3.10 ± 0.13c 6.62 ± 0.42c.d 0.10 ± 0.13a
Premise† 2.39 ± 0.17b 7.48 ± 0.71d 0.10 ± 0.13a
tPh3† 3.07 ± 0.15c 9.08 ± 1.11e 0.12 ± 0.01a