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Dental Science:
Scientific Information
Translux® 2Wave
Pulp temperature during polymerisation – Georgia Regents University,
Augusta, USA
In vitro intrapulpal temperature rise of 2 new LED lights.
Dental light curing materials can unfold their optimum material properties (e. g. mechanical strength,
bond strength, biocompatibility) only when they are polymerised sufficiently.
Many factors during the light curing are influencing the polymerisation result. Apart from the light curing
technique and material-related conditions, the curing light itself has an impact on the polymerisation
result. When selecting a light curing unit it is from vital importance to make sure that it fits to the dental
material which needs to be cured. A pre-condition for this is that the light needs to emit light in the wavelength range of the sensitivity of the photoinitiators used in the material. Further the irradiance (the light
output related to the area) needs to be high enough to activate the photoinitiators. But the irradiance
of curing lights can only be increased to a certain limit. A greater potential risk for heat-induced pulp
damage might be associated with high-power LED sources1. Curing devices with high power density
(> 1200 mW/cm²) should only be activated for a short period of time2. Finally, the output of the curing
unit needs to be checked regularly to ensure that a sufficient polymerisation is possible.
The following study performed by Prof. Rueggeberg of the Georgia Regents University demonstrates the
low pulp temperature increase the Translux 2Wave develops during curing. Further, it shows that the wavelength spectrum fits to the camphorquinone photoinitiator which is mainly used in dental light curing
composites. Due to its additional violet LED die the Translux 2Wave activates also photoinitiators which
require lower wavelengths like e. g. PPD, TPO or TPO-L.
Giving a hand to oral health.
Pulp temperature during polymerisation – Georgia Regents University,
Augusta, USA
In vitro intrapulpal temperature rise of 2 new LED lights.
Objective
This project will measure and compare the in vitro intrapulpal temperature rise when exposing an empty, 4-mm deep, Class I
preparation in an extracted, human molar to a variety of LED-based dental light curing units. Further, the spectral irradiance
was measured, and the total energy output was calculated and reported.
Materials & Methods
The tested light curing units were: Translux Wave and Translux 2Wave (both Heraeus Kulzer), S.P.E.C.3 (Colténe/Whaledent),
Bluephase Style (Ivoclar Vivadent) and Elipar S10 (3M ESPE). The Translux Wave, Translux 2Wave, Bluephase Style and Elipar
S10 were used in the standard mode for 20bs, whereas the S.P.E.C.3 was used in the 3K mode for 2 x 3bs. The roots of an extracted
human molar were shortened. The pulp was extirpated and tubing was then cemented to the roots. A section of tubing was
connected to one tube end and a portion of the remaining end was coiled to increase surface area in contact with the warmed
water in which it was immersed. The distal end of the tubing was connected to a water-filled, glass syringe simulating physiological fluid flow.
2 mm
THERMOCOUPLE LEADS TO
DIGITAL INTERFACE
6 mm
LIGHT
LIGHT
CURING
CURING
TIP
4 mm
SOLAR CELL TO MONITOR
CURING LIGHT
ACTIVATION
RESERVIOR
RESERVOIR
AND
OVERFLOW
OVERFLOW
MOTOR-DRIVEN SYRINGE
PLASTIC PLATE
TEMPERATURE
TEMPERATURE
CONTROLLED
CONTROLLED
WATER
WATER BATH
BATH
THERMOCOUPLE
TO MONITOR
WATER BATH
TEMPERATURE
OUTLET
OUTLET
INLET
INLET
ERLENMEYER
ERLENMEYER
FLASK
FLASK
WARMING
WARMING COIL
COIL
Depiction of test set-up used for measuring simulated intrapulpal
temperatures
A thermocouple was positioned so that it rested directly against the coronal pulpal wall opposite the pulpal floor of a Class I
preparation made in the tooth. The thermocouple output was connected to a computer. The software both visually displayed and
digitally recorded the thermocouple temperature in real-time at a rate of 10 data points per second. A solar cell helped to determine the exact time when the light unit was activated and deactivated. The roots of the prepared tooth were placed through an
opening of a plastic plate that covered the top of the Erlenmeyer flask. The flask itself rested in water of a temperature-controlled
bath (Thermo-Lift, Model I-2000, Buchler Instruments, Inc., Fort Lee, NJ). Water temperature was thermostatically controlled
to provide an intrapulpal temperature of approximately 35b°C (± 0.5b°), which is similar to that of the in vivo condition. The average
real-time time-temperature plot developed from performing five separate replications of exposure for each light unit were obtained.
Statistical analysis of temperature values obtained at the desired exposure durations was obtained using a 1-way analysis of
variance. If that test indicated statistical significance, the Tukey post-hoc, pair-wise means comparison test was performed. All
statistical testing was performed at a pre-set alpha of 0.05.
The spectral irradiance was measured (n = 5) using an integrating sphere which was connected to a spectroradiometer, the output of which was fed to a software on a personal computer. In order to calculate irradiance, the emitting area at the tip end was
calculated using the beam profiling device. The emitted beam diameter from that analysis was then used to divide the calculated
power values into units of irradiance.
1
2
Baroudi K, Silikas N, Watts DC: In vitro pulp chamber temperature rise from irradiation and exotherm of flowable composites. Int J Paediatr Dent, 19,1,
2009:48-54.
Park S-H, Roulet J-F, Heintze SD: Parameters influencing increase in pulp chamber temperature with light-curing devices: curing lights and pulpal flow
rates. Oper Dent, 35,3, 2010:353-61.
Results
Translux 2Wave induces only low temperature change in the pulp
Mean intrapulpal temperature [°C]
6
Benchmark treshold for possibly causing pulpal necrosis
5
4
B
B
A
A
A
Bluephase Style
Elipar S10
S.P.E.C.3 (2 x 3bs)
Translux Wave
Translux 2Wave
3
2
1
0
Similar upper case letters are not statistically significantely different.
Irradiance [mW/cm²/nm]
Translux 2Wave is matched to camphorquinone and
newer violet light activated photoinitiators
10
8
TPO-L
6
4
2
0
350
PPD
TPO
Emisson Translux® 2Wave
Translux 2Wave
Bluephase Style
CQ
400
450
Wavelength [nm]
500
PPD (1-Phenylpropane-1,2-dione)
CQ (Camphorquinone)
TPO-L (Ethyl-2,4,6-trimethylbenzoyl-phenylphosphinate)
TPO (Diphenyl-2,4,6-trimethyhlbenzoyl-phosphine oxide)
Light curing unit
Energy density [J/cm²]
S.P.E.C.3 (2 x 3bs, ORTHO mode)
22.3
Elipar S10 (20bs)
21.7
Bluephase Style (20bs)
18.7
Translux Wave (20bs)
19.8
Translux 2Wave (20bs)
21.8
From this graph, it indicates that the irradiance of the
Translux 2Wave in both the blue and violet spectral regions
is similar with respect to wavelength, but the irradiance of
the Translux unit exceeds that of the Bluephase Style at
both major output regions.
Two distinct wavelengths of emission are seen from the
Translux 2Wave. The longer, blue wavelength is centered
near 460bnm, while the shorter wavelength, violet chip is
located near 406bnm. The Translux 2Wave exhibited an irradiance of 1088 ± 9bmW/cm² (measured with integrating
sphere + spectroradiometer).
When used for a 20-second exposure, the total emitted
energy density (irradiance multiplied by exposure duration)
of the Translux 2Wave was 21.8bJ/cm².
Conclusion
In short, intrapulpal temperatures observed using the new
Heraeus Kulzer Translux 2Wave was not remarkably different from those of competitive, commercial products. None
of the light units exceeded an intrapulpal temperature rise
of 5.5b°C, which has been attributed with the presence of
pulpal necrosis in rhesus monkeys 3.
Source
Rueggeberg F: REPORT – In vitro intrapulpal temperature rise of 2 new LED lights, November 2013. Unpublished data.
Data on file. The study was abbreviated and summarised and all diagrams and titles have been established by Heraeus Kulzer.
Translux is a registered trademark of Heraeus Kulzer.
3
Zach L, Cohen G. Pulp response to externally applied heat. Oral Surgery Oral Medicine and Oral Pathology 19:515-530, 1965.
Contact in Germany:
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Berkshire, RG14 1DL
Phone +44 1635 30500
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www.heraeus-kulzer.com
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Macquarie Park NSW 2113
Toll Free: 1800 226521
Phone +61 2 8875-7765
Fax +61 2 9888-1460
[email protected]
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