Indiana University-Purdue University Indianapolis (IUPUI) / The purpose of this study is to further investigate the effect of using six different light source
types with different light output intensities on the parameters of a mathematical model that predicts
the DOC in VLDC’s. In this equation: D = Dp In(E0/Ec), D is the depth of cure in millimeters, E is
the curing energy in J/cm2, Ec is the critical curing energy for the composite to reach a gel layer, and
Dp is a characteristic coefficient.
Three LED and three halogen dental curing units with different light output intensities were
used to cure three shades (B1, A3, D3) of a hybrid resin composite. The exposure duration was at
the intervals of 10, 20, 30, and 40 seconds for each sample setting. ISO scraping technique was
performed to measure the depth of cure of each sample. Regression analysis was used to assess the
fit of the proposed mathematical model D = Dp In(E0/Ec) to the experimental data obtained in this
study.
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For all the shade-light combinations; A3, B1, and D3 had significantly different regression
lines (P < 0.05) with significantly higher Dp and Ec for B1 than A3 and D3. The only exceptions
were for the Ec values between B1 and D3 in Allegro, Astralis 5, and Visilux 2 groups; and the Ec
between A3 and B1 in Allegro group. The Dp and Ec parameters didn’t show significant differences
between A3 and D3 shades in all the groups. Also, most of the significant differences for Dp values
occurred in the B1 shade-light combinations; however, none of the D3 shade-light combinations
showed significant differences for Dp.
Several factors play combined influential effects on the kinetics of polymerization and depth of
cure in VLDC’s. The shade has a more dominant effect on both parameters Dp and Ec than the
curing light type or source output intensity. As we cure lighter shades “B1,” the effect of using
different lights with different output intensities on the two parameters Dp and Ec will be greater and
more significant than for darker shades “A3 or D3.” The clinical significance drawn from this study
is that clinicians should recognize that using curing lights w/ increased output intensities doesn’t
absolutely increase the DOC of VLDC’s especially with the darker shades.
| Identifer | oai:union.ndltd.org:IUPUI/oai:scholarworks.iupui.edu:1805/2082 |
| Date | January 2009 |
| Creators | Ridha, Hashem |
| Contributors | Levon, John A., Andres, Carl J., Chu, Tien-Min Gabriel, Brown, David, Hovijitra, Suteera |
| Source Sets | Indiana University-Purdue University Indianapolis |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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