December 26, 2014

What is Dental Curing light

What is dental curing light 

dental curing light is a piece of dental equipment that is used for polymerization of light cure resin based composites.[1]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 lights; Tungsten halogen, light-emitting diode (LED), plasma arc curing (PAC), and laser. The two main dental curing lights are the halogen and LED.

Halogen Dental Cuirng Light 

The Tungsten halogen curing light, also known as simply “halogen curing light” is the most frequent polymerization source used in dental offices.[6] In order for the light to be produced, an electric current flows through a thin tungsten filament, which functions as a resistor.[6] This resistor is then “heated to temperatures of about 3,000 Kelvin, it becomes incandescent and emits infrared and electromagnetic radiation in the form of visible light”.[6] It provides a blue light of about 400 and 500 nm, with an intensity of 400- 600 mW cm^-2.[7] This type of curing light however has certain drawbacks, the first of which is the high temperatures that the filament generates. This requires that the curing light have a ventilating fan installed in order to “force airflow through slots in the casing”.[6] This requires the curing light to be larger, in order to house the fan. The fan generates a sound that may disturb some patients, and the wattage of the bulb is such (e.g. 80W) these curing lights must be plugged into a power source, that is, they are not cordless. Furthermore, this light requires frequent monitoring and replacement of the actual curing light bulb because of the high temperatures that are reached. (For example, one model uses a bulb with an estimated life of 50 hours which would require annual replacement, assuming 12 minutes’ use per day, 250 days per year.) Also, the time needed to fully cure the material is much more than the LED curing light

LED Dental curing light 

These curing lights use one or more light-emitting diodes [LEDs] and produce blue light that cures the dental material. LEDs as light-curing sources were first suggested in the literature in 1995.[8] A short history of LED curing in dentistry was published in 2013.[9] This light uses a gallium nitride-based semiconductor for blue light emission.[6]

A 2004 article in the American Dental Association‘s journal explained, “In LED’s, a voltage is applied across the junctions of two doped semi- conductors (n-doped and p-doped), resulting in the generation and emission of light in a specific wavelength range. By controlling the chemical composition of the semiconductor combination, one can control the wavelength range. The dental LED curing lights use LED’s that produce a narrow spectrum of blue light in the 400- to 500-nm range (with a peak wavelength of about 460nm), which is the useful energy range for activating the CPQ molecule most commonly used to initiate the photo-polymerization of dental monomers.”[6]

These curing lights are very different from halogen curing lights. They are more lightweight, portable and effective. The heat generated from LED curing lights is much less which means it does not require a fan to cool it. Since the fan was no longer needed, a more lightweight and smaller light could be designed. The portability of it comes from the low consumption of power. The LED can now use rechargeable batteries, making it much more comfortable and easier to use.

The newest[when?] LED curing light is the HP (high powered LED light). It is an updated LED curing light that cures material much faster than the Halogen and the previous LED curing lights. It uses a single high-intensity blue LED with a larger semi conductor crystal.[6] Light intensity and the area that is illuminated has been increased with an output of 1,000 mW/cm2.[6] In order to emit such a high intensity light, it uses a highly reflective mirror film that consisting of “multilayer polymer film technology.

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