Vol 21 No. 1

J Bagh College Dentistry Vol. 21(1), 2009 Depth of cure evaluation…..
U.S.A. Lot: 205466.Item No.: 22860) and
Degufill Mineral (Degussa-Hüls AG, Degussa
Dental GmbH & Co. KG, Postfach 1364. D-
63403 Hanau, Germany.Lot: 0885).
For the preparation of a cylindrical specimen,
a two-piece aluminum mold with a diameter of
4mm and a height of 8mm (Iraqi construction)
was used as a mold for the composite specimens.
A Transparent celluloid strip band (Hawe-Neos
Dental, CH-6925 Gentilino, Switzerland) was
placed on a flat glass slide (Blue star glass
industries, Delhi, India) (Blue star glass
industries, Delhi, India) on top of a white filter
paper (England) then, the mold was placed over
the transparent celluloid-strip and slightly
overfilled it in one increment with the composite
materials being tested then, a second transparent
celluloid-strip was placed on top of the mold and
overlaid it with a cover slide, then a finger
pressure was applied to the cover slide to extrude
excess material. The exit window of the curing
light was placed over the cover slide (the light tip
in contact with the cover slide) and each
composite material was irradiated, through the
transparent celluloid strip and the cover slide,
with the nine different curing modes (Table 1 &
2).
One hour after completing irradiation, the
composite specimen was removed from the mold
and the uncured material at the bottom of the
sample, was removed by scraping it away
manually with a plastic spatula. The height of the
cylinder of cured material was measured with a
micrometer (Hommel Werke, England) to an
accuracy of 0.01 mm (Figure 1). This value was
divided by two (in compliance with ISO CD4049:
2000), and recorded it as the depth of cure.
Mean and standard deviation were calculated
for each specific depth of cure. The results were
analyzed with one-way ANOVA and Least
significant difference (LSD)-test at significance
level 0.05.
RESULTS
Mean depth of cure in mm and standard
deviation of the four different light-activated
composites cured with the nine-different curing
modes are listed in Table 3. Figure 2 summarizes
mean depth of cure of the four different lightactivated
composites cured with the nine-different
curing modes. Statistical analysis of the data by
using the one-way analysis of variance revealed
that, there is statistically very highly significant
difference for all the depth of cures between the
curing modes and composite types. LSD-test of
the depth of cure according to the composite type
is summarized in Table 4.
Table 1: The conventional light- curing
Light-curing
mode
Control (CC)
Pulse Delay I
(PDI)
Pulse Delay II
(PDII)
Soft-start (SS)
Pulse Cure I
(PCI)
Pulse Cure II
(PCII)
modes (6) .
Regimen
400mW/cm2
(40 seconds)
100mW/cm2→Delay→
500mW/cm2 (3 seconds)
(3 minutes) (30 seconds)
200mW/cm2→Delay→
500mW/cm2 (20 seconds)
(3 minutes) (30 seconds)
200mW/cm2 → 600mW/cm2
(10 seconds) (30 seconds)
400 mW/cm2→Delay→ 400
mW/cm2→
Delay→ 400 mW/cm2 (10
seconds)
(10 seconds) (10 seconds)
(10 seconds) (20 seconds)
400 mW/cm2→Delay→ 400
mW/cm2
(20 seconds) (20 seconds) (20
seconds)
Table 2: The experimental light-curing
modes used in this study (7) .
Light-curing mode
Prolonged lowintensity
pulse cure mode
(PLPC)
Prolonged moderateintensity
pulse cure mode
(PMPC)
Rapid high-intensity
continues cure mode
(RHCC)
Regimen
100mW/cm2 → Delay →
300 mW/cm2
(20 seconds)(10
seconds)(120 seconds)
100mW/cm2 → Delay →
400 mW/cm2
(20 seconds)(10 seconds)
(90 seconds)
600mW/cm2
(60 seconds)
Figure 1: The micrometer devise for
measuring the depth of cure.
Restorative Dentistry 6