Dental Light Cure

Dental curing lightApplication & working

Author: Lokender Yadav

Market Challenges

1_ Decrease number of components.

2_ Make the device more comfortable for doctor and patient, beautiful and small for easy used.

3_ Use a suitable chargeable battery..

4_ Reduce the cost of the device.

Dental curing lightUsage of device:

Dryness of the white composite for teeth by using laser blue led.

What is the Composite?It is A mixture of plastic and fine glass particles.

Used for: Small and large fillings, especially in front teeth or the visible parts of teeth; also for inlays

Lasts: At least five years

Product In the market:-

A dental curing light is a piece of dental equipment that is used for polymerization of light cure

There are two main dental curing lights are the halogen and Blue LED.

Need of light cure

The crucial point to contemplate during restorative dentistry procedures with composite resins is to obtain satisfactory restorations with an adequate photo polymerization technique. This procedure requires sufficient light energy intensity and an adequate wavelength in order to activate the photo initiator within these materials, which will react with the reducer agent to form free radicals and initiate the polymerization process.

What is photo polymerization?

In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks.

A photopolymer is a polymer that changes its properties when exposed to light, often in the ultraviolet or visible region of the electromagnetic spectrum. These changes are often manifested structurally, for example hardening of the material occurs as a result of cross-linking when exposed to light. An example is shown below depicting a mixture of monomers, oligomers, and photo initiators that conform into a hardened polymeric material through a process called curing.

Cross-linking

Light Spectrum

Light curing options

Type of curing Unit PROS CONS

Halogen(QTH-quartz tungsten halogen)

• Low cost technology• Longest history in

dental industry

Low efficiency Short service High

temperature(ventilating fan required)

Continuous spectrum must be narrowed by filters

PAC(Plasma Arc) • Shorter polymerization time

All above CONS + high cost

LASER • Low heat generation Negative Perception about curing due to high curing speed

High cost

LED • No need for filter sys

• High efficiency/min heat

• Long service life• Consistent O/P• Quiet operation

Due to narrow emission LED can polymerize 440 to 480nm and CPQ

Relatively new to dental industry

CPQ-468nm

1.Old Light Cure

Operates with halogen lamp.

Disadvantage: consume high power.

principle of Tungsten halogen

In order for the light to be produced, an electric current flows through a thin tungsten filament, which functions as a resistor.

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”.

It provides a blue light of about 400 and 500 nm, with an intensity of 400- 600 mW

2.Using Blue Led

is most widely used .

2.1wireless:

Disadvantages: the chargeable battery is weak.

2.2hand with adaptor

Wireless Light Cure

better than the wireless

Principle of using blue led

it uses light-emitting diodes that produce blue light that cures the dental material.

This light uses a gallium nitride as a semiconductor that is the basis for the blue emission.

“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.

Principle of blue led: 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.

These curing lights are much different than the Halogen curing lights.

They are more lightweight, portable and effective.

Principle of blue led:The heat generated from LED

curing lights is much less which means it does not require a fan to cool it. Now that the fan is not 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

What is CPQ

Camphor Quinone (CQ) is the most common photo initiator used in composites, and it presents maximum energy absorption at 468 nm within the electromagnetic spectrum close to the emission spectrum of the light-emitting diode (LED λ- X: 450-490 nm) light-curing unit (LCU).

Modes of the curing unit:-

1. Continuous lightning for 15 sec.

2. Pulsed lighting every sec for 15 sec.

3. Graduate increasing in light intensity for 15 sec.

Why modes in curing unit

Because of the theory, which says that when the composite material is exposed to light directly, it expands and cracks .

Instrument Function

Harden of the white composite for teeth by using light blue led .

visible spectrum output (lights)that lies within a specific wavelength range .

The idea is that the setting catalyst contained by this particular color (wavelength) of light.

Actually dentist use curing lights to activate the set of a wide range of different types of dental materials.

With most dental products including most dental composites the light wavelength needed to activate the curing process lies somewhere within the range of 420 to 450 nm .

This means that the light emitted from the typical dental curing light will have a violet to blue coloration

1. Block Diagram

Power ct.It will be Battery or Adaptor.

•Power 5v•Micro Controller Circuit

•Blue Led

MYTHs About LED CURING

MYTH 1: Intensity is the most important factor in Choosing a curing light.

Actually, matching the wavelength of the curing light to the absorption spectrum of the photo initiator is the most important factor in curing dental materials. Only when this is done correctly will intensity change the outcome of the cure.

For example, it is possible for a curing light to be more intense than another but leave a material uncured because the wavelength didn’t match the photo initiator value.

MYTH 2: The more LEDs that a curing light contains, the better it is at curing materials.

The no of LEDs in curing light doesn’t necessarily have any bearing on the spectral output of the unit, no matter if it has 64, 19 or one LED. In culture where more is better is difficult to understand , but there are multiple types of LEDs and each is unique in its performance.Different LEDs have different intensities , so curing light with one very intense LED could be more powerful than a curing light with 64 less-intense LEDs.Curing Light Output depends on three things: Spectral output of the LED Wavelength Intensity of the LEDs Optical Light DeliverySo judging the LED curing by no of LEDs present is does not make any sense.

MYTH 3: LED curing lights are a very slow way to cure

material.LED curing lights are able to cure materials in time comparable to conventional halogen lights. They can do this by utilizing a narrow wavelength that most closely matches CPQ, the Photointiator mainly used in composite materials. This narrow and well matched wavelength to efficiently cure materials with little wasted light output.

Why BLUE Light is used…… in dental curing?

Because all the photointiator used in dental materials absorb the light in the range of 400-500nm range and this range of wavelength is lying in blue light region

Hope you Learned Something