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Light Curing Devices
1. QTH LAMPS
2. ARGON LASER LAMPS
3. PAC LAMPS
4. LED LAMPS
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Quartz-Tungsten-Halogen
Most common dental curing light
Quartz
Encasing structureCrystalline
Heat resistant
Tungsten
Filament coil
Flow of electricity
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Quartz-Tungsten-Halogen
Halogen gasProtects filament from
oxidation
Re-deposits tungstento filament halogen cycle
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Quartz-Tungsten-Halogen
Radiant output
infrared energy (IR)
heatCooling critical
Do not turn off fan
Halogen gas lost
Oxygen enters
Bulb life dramatically decreases
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Quartz-Tungsten-Halogen
Filters
restricts broader light
to narrow blue light400-500 nm
range of photo-initiators
99.5% of original radiant energyfiltered
inefficient
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ARGON LASER
Introduced in 1964
Produces a wavelength of 488nm
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Argon Laser
High energy
coherent, non-divergentVery expensive
Warning signs required
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PAC Devices
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Plasma-Arc (PAC)
Two tungsten electrodes
small gap
Pressurized chamber
xenon gas
High-voltage spark ionizes gas
plasma
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Plasma-Arc (PAC)
High levels of IR and UV
extensive filteringdown to 400-500 nm
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Plasma-Arc (PAC)
High irradiance
> 2000 mW/cm2
claim 1-3 sec cure
Expensive
Less Depth of Cure
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Light emitting diode
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Light-Emitting Diodes (LED)
Semiconductors
electrically-excited atoms
Gallium-nitride blueGallium - Arsenide
Narrow emission spectrum
430-490 nm
peak at 470 nm
efficient
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LED Curing Lights
Long lasting light source
minimal ageing
minimal decrease in output Less lateral heat production
minimal or no fan
necessary No filters
Typically cordless
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LED Curing Lights
First generation
high cost
low irradiance
< 300 mW/cm2
increase exposure time
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LED Curing Lights
Second generation
lower cost
higher irradiance
> 600 mW/cm2
similar to halogen
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Depth of cure andExposure time
Degree of conversion
Opacity, filler size, filler
concentration and pigment shadeof the composite resin.
Absorption and scattering of light
by tooth structure especially dentin.
Quality and intensity of light sourceas well as age of light source.
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Clinical Techniques
Incremental build up
cavity configuration
Soft start
ramped curing
delayed curing
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PRECAUTIONS FOR USINGCURING LAMPS
The dentist and the patient mustwear protective glasses
Curing light should be as close aspossible to composite
Curing tip should be clean
Use incremental technique only
Irradiance should be checkedperiodically
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hank You