2803 Disaggregated Light Transmission Through Saturated Resin Based Composite

Saturday, March 23, 2013: 8 a.m. - 9:30 a.m.
Location: Room 611 (Washington State Convention Center)
Presentation Type: Oral Session
C. FELIX, BlueLight analytics inc, Halifax, NS, Canada, and A. SANTINI, University of Edinburgh, Edinburgh, Scotland
Objectives: To identify the relationship between violet (380-420 nm) and blue (420-540 nm) light transmission through different shades and thicknesses of light saturated resin based composite(RBC).

Methods:   Bluephase (single-peak) and Bluephase G2 (dual-peak) [Ivoclar Vivadent, Schaan, Liechtenstein] light curing units (LCUs) were mounted on a MARC® Resin Calibrator (BlueLight analytics inc., Halifax, Canada) adjusted to deliver 1000mW/cm2 to RBC samples during 10 second curing cycles.  Samples(x3) of three thicknesses of Tetric EvoCeram RBC, shades A2, D3, Bleach I and Bleach XL, [Ivoclar Vivadent, Schaan, Liechtenstein] were prepared in 6mm internal diameter Delrin® rings.  Photoinitiator light saturation was achieved in 1 mm thick samples after approximately 20 J/cm2, 2 mm samples after 40 J/cm2 and 3 mm samples after 60 J/cm2. Energy transmission was then measured during one final 10 second curing cycle and shown in both 380-420nm and 420-540nm  spectral ranges. The percentage of light transmission was calculated for each spectral range, for all shades and thicknesses. Measurements were repeated three times, the means and standard deviations calculated. Statistical analysis was performed using Minitab 15 (Minitab Inc., State College, PA, USA). General linear model ANOVA was used to test the differences for the factors ‘LCUs’, ‘ shade’ and ‘thickness’ and their interaction at α=0.05.

Results:  Table 1 gives the energy transmission percentages through saturated RBCs.Single-peak LCU gave a significantly lower % transmitted blue light than the dual-peak LCU (p<0.05). The % transmitted blue was significant higher than violet light for the dual-peak LCU (p< 0.001). The proportional difference between blue and violet light transmitted was mainly effected by sample thickness, with shade being of borderline significant (p<0.05).

Conclusions: Percentage transmission of light in the 380-420nm range was less than the 420-540nm range. This may have clinical significance when curing RBCs containing photoinitiators other than camphorquinone.

Table 1

Shade

Thickness

Percentage of Light Transmitted to the Bottom Surface

Blue (single peak)

Blue (dual peak)

Violet (dual peak)

A2

1 mm

29.4 ± 0.6

29.7 ± 0.2

10.6 ± 1.9

2 mm

13.9 ± 0.2

16.8 ± 0.3

3.5 ± 1.0

3 mm

6.9 ± 0.1

8.4 ± 0.2

1.7 ± 1.0

Bleach I

1 mm

45.0 ± 0.7

45.8 ± 0.2

21.3 ± 0.6

2 mm

29.9 ± 0.1

31.9 ± 0.1

9.2 ± 0.4

3 mm

20.6 ± 0.2

25.6 ± 0.2

5.8 ± 0.4

Bleach XL

1 mm

25.0 ± 0.2

24.1 ± 0.1

5.0 ± 1.7

2 mm

9.4 ± 0.1

10.4 ± 0.8

2.7 ± 0.4

3 mm

4.4 ± 0.1

5.2 ± 0.2

1.0 ± 0.4

D3

1 mm

27.1 ± 0.6

27.9 ± 0.5

10.4 ± 0.4

2 mm

11.5 ± 0.2

13.1 ± 0.2

3.8 ± 1.1

3 mm

5.5 ± 0.2

6.5 ± 0.1

1.3 ± 1.1


Keywords: Composites, Curing lights, Dental materials, Polymerization and light wavelength
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