Light Curing
Light Curing is the energy to fully polymerize the light cure based dental material.
It can be used on several different dental materials that are curable by light.
The light used falls under the visible blue light spectrum.
This light is delivered over a range of wavelengths and varies for each type of device.
There are four basic types of dental curing light sources: tungsten halogen, light-emitting diodes, plasma arcs, and lasers.
The two most common are halogen and LEDs.
There are two types of LED curing lights: those that contain blue-only LEDs and poly-LED curing lights .
Most manufacturers have stopped making Halogen curing lights, partly because LED lights are more efficient than halogen light sources, but also because the incandescent bulbs of it will soon become scarce.
How much light produced?
Halogen light deliver a broad spectrum of light of 400 mW/cm2 during 40 seconds of curing.
LED curing lights that contain blue-only LEDs and provide blue light within a narrow spectral range of 440 nm to 490 nm, and poly-LED curing lights that deliver a broader spectrum of light in the range of 390 nm to 490 nm.
Resin composite’s instructions for use states that the curing light’s minimum irradiance output should be at least 300 mW/cm2 to 400 mW/cm2.
Currently, most QTH curing lights deliver at least 600 mW/cm2, and some lights that use specialized turbo tips can deliver more than 1,300 mW/cm2.
The latest generation of LED curing lights can deliver an irradiance output greater than 2,000 mW/cm2, and some poly-LED curing light devices include supplemental LEDs that emit light at additional wavelengths
Depending on the shade and brand of composite resin, the minimum energy requirements to photopolymerize resins range from 6 J/cm2 to 24 J/cm2 for a 2-mm increment of composite.
So in 20 seconds 16 J/cm2 is delivered to polymerize the material used.
Not all lights are the same. They do not deliver the same amount of light.
eg;- Valo, Demi, Radical
COLLIMATION
Light must be focused.
Lense to focus light. It can be of acrylic or optic fiber.
Light as Wave ( Colours )
The need for different wavelenght is a hidden reality.
whichever colour is being emitted ,it should be homogeneous.
Tips for Using a Curing Light
Before use, inspect the light guide tip and remove any contaminants on the surface.
The light tip should be at right angles to the tooth surface being restored .
Stabilize the light when curing; use a finger rest.
Begin curing 1 mm away from tooth; after 1 second bring the tip as close to the tooth as possible.
Increase the light exposure time for preparations more than 2 mm to 3 mm deep .
DR.RENJU T GEORGE,
INDIA.
