LIGHT EMITTING DIODE (LED)

• The LED emits RADIATION only in the BLUE PART OF THE VISIBLE SPECTRUM (440-480nm)

• because of this LED DO NOT REQUIRE FILTERS

• The LED is very EFFICIENT at CONVERTING ELECTRICAL ENERGY to ELECTROMAGNETIC RADIATION

• Light emitting diode (LED) units usually have a LONG LIFE and emit POWERFUL BLUE LIGHT

• This light falls in a NARROW WAVELENGTH RANGE of 455 nm to 486 nm.

• This corresponds to the range of CAMPHORQUINONE PHOTOINITIATOR found in most COMPOSITE RESINS

describe LED

radiation
blue part of the visible spectrum
440-480nm
filters

The LED emits [?] only in the [?] ([?])

• because of this LED do not require [?]

electrical energy
electromagnetic radiation

the LED is very EFFICIENT at CONVERTING [?] to [?]

powerful blue light
455 - 486 nm
camphorquinone photoinitiatior
composite resins

Light emitting diode (LED) units usually have a LONG LIFE and emit [?]

• This light falls in a NARROW WAVELENGTH RANGE of [?]. This corresponds to the range of [?] found in most [?]

1. LOW power consumption

2. It can also be used with BATTERIES

3. It DOES NOT require FILTER

4. LONG LIFE (10,000 hours approximately) 5 MINIMAL CHANGES in LIGHT OUTPUT OVER TIME

advantages of LED

Only suitable for CAMPHORQUINONE BASED COMPOSITES (because it has limited wavelength spectrum)

DISADVANTAGE OF LED

• Was called “COOL” LIGHTS, because it produced LESS HEAT, and LESS TEMPERATURE RISE in the PULP than the QTH light curing units

• The LOW HEAT GENERATION of this curing unit is due to their LOW RADIANT POWER OUTPUT (470nm)

• This curing unit is INCOMPATIBLE with LUCIRIN and TPO

Describe first generation LED

less heat
less temp rise
pulp

first generation LED was called cool lights because it produced [?] and [?] on the [?] than the QTH light curing units

low radiant power output (470nm)

first generation:

The LOW HEAT GENERATION of this curing unit is due to their [?]

• Uses new HIGH OUTPUT BLUE LED CHIPS, which resulted in a REDUCED recommended EXPOSURE TIME than QTH

• An INTERNAL COOLING FAN and a LARGE METAL SINK were added to this curing unit, because the INCREASED RADIANT POWER OUTPUT also INCREASED HEAT OUTPUT

• This curing unit is INCOMPATIBLE with LUCIRIN and TPO

describe second generation LED

high output blue LED chips
reduced
exposure time

second generation LED uses [?] which resulted in [?] recommended [?] than QTH

internal cooling fan
large metal sink
radiant power output
heat output

in second generation LED, an [?] and [?] were added to this curing unit because the increased [?] and also increased [?]

LUCIRIN and TPO

first and second generation LED in incompatibel with?

more than one wavelength

IN third generation LED, the light curing unit can emit light of [?]

• The light curing unit then can EMIT LIGHT OF MORE THAN ONE WAVELENGTH RANGE

  • Achieved by INCORPORATING DIFFERENT LED COLOR CHIPS that can emit both LOWER WAVELENGTHS of 390-430nm (violet light) and HIGHER WAVELENGTHS of 440-500nm

  • This curing unit can ACTIVATE ALL THE PHOTOINITIATORS used for composite resins

describe 3rd gen LED

different LED color chips
lower wavelengths
390 - 430nm
higher wavelengths
440 - 500 nm

third generation LED can emit light of more than one wavelength by incorporating [?] that can emit both [?] of [?] and [?] pf [?]

photoinitiators
composite resins

third generation can activate all [?] used for [?]