Verlängerung der Verarbeitungszeit von Kompositen mit einer neuartigen weißen LED-Arbeitsfeldbeleuchtung
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Philipps-Universität Marburg
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Abstract
Most light-curing composites for dental fillings contain the photoinitiator
camphorquinone, which can be cured by a polymerisation lamp with blue light.
However, the same range of wavelengths is also emitted by common operating lamps,
so that the composite hardens unintentionally earlier. The surface of the composite
becomes brittle and cracks appear when modelling is continued so that the material
has to be replaced.
The current solution to this problem is to reduce the illuminance of the light source.
Alternatively, the critical spectrum below 500 nm can be filtered out or a yellow LED
with a spectrum above 500 nm can be used. Both solutions of extending the working
time create an uncomfortable lighting condition and reduce the perceptibility of
contrasts for the dentist.
Based on this problem, a phosphor-conversion light emitting diode (LED) is developed
in the presented study, which emits white light and offers a longer working time of
composites with camphorquinone than conventional LED headlamps. First, the
excitation LED of the phosphor-conversion white LED was set with an emission
maximum at 425 nm. It emits light in a range where the ratio between a low excitation
of the photoinitiator camphorquinone and a high excitation of the S-cone in the eye is
particularly favourable. Based on this LED, a fluorescent substance was selected for
combination with it that emits light above 500 nm. The evaluation of the LEDs was
carried out by the working time of composites containing camphorquinone with an
acoustic measuring system at an illuminance of 10,000 lx. The colour temperature and
spectra were taken into account in the analysis of the LEDs.
Based on the results of the preliminary tests, a white LED was developed and produced
by OSA Opto Light GmbH. The working time with this LED was between 6:40 min and
13:20 min at an illuminance of 10,000 lx for different composites. Compared to a
headlamp, this is an extension of the working time by a factor of 3 to 5.5. The colour
temperature is 3,000 K and is perceived as white.
This white LED enables the dentist to model light-curing composites for filling teeth
with a sufficiently long working time. In addition to the increased working time, the
modelling is supported by a white working light.
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Dates
Created: 2023Issued: 2023-12-04Updated: 2023-12-05
Faculty
Medizin
Publisher
Philipps-Universität Marburg
Language
ger
Data types
DoctoralThesis
Keywords
CampherchinonphotoinitiatorweißKompositlight curingcamphorquinoneLEDdental fillingVerarbeitungszeitLEDZahnfüllung
DFG-subjects
ZahnmedizinAushärtungLumineszenzdiodeVerbundwerkstoff
DDC-Numbers
610
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von Bülow, Albrecht: Verlängerung der Verarbeitungszeit von Kompositen mit einer neuartigen weißen LED-Arbeitsfeldbeleuchtung. : Philipps-Universität Marburg 2023-12-04. DOI: https://doi.org/10.17192/z2023.0605.
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