Dental Curing Light

A dental curing light is defined as dental equipment used to cure resin-based composites by polymerization of light. Polymerization is the term used for transforming ‘monomers’ into ‘polymers’. In short, any implants or dental attachments besides the natural teeth are being clean and strengthened by a particular light source.

Cured light is a very strong blue light.  It is not a laser or UV lamp, so it will not cause any damage to your teeth or gums. The only danger is if you look directly at the light for a long time. Similar to if you look at the sun for too long your eyes will hurt. Dentists and assistants are advised not to look at the lights for long periods of time.

Dentists use two types of curing lamps. There are halogen curing lamps and LED curing lamps. Most modern curing lamps are LEDs because they do not overheat like halogen curing lamps. The only danger of a halogen lamp is that the heat it produces can damage the pulp or soft tissues in the mouth. While this is possible, it is unlikely. Today, most dentists use LED curing lights.

• Over the past 50 years, the ability to easily and efficiently cure polymer-based prosthetic materials using light energy has revolutionized the dental landscape.
• For a light-cured resin-based restoration to function and last as intended, it must receive the required amount of light energy at the proper wavelength (i.e., the wavelength of the photoinitiator) to facilitate optimal polymerization (or curing).
• To deliver the required amount of light energy, it is necessary to understand how clinical variables such as curing tip distance and angle of incidence with respect to the restoration surface influence the curing process, as well as exposure time and curing tip diameter.
• Proper infection control procedures when using curing lights support both patient safety and equipment maintenance.
• It is important to consider that curing lights can cause an intrapulpal temperature rise. Proper eye protection helps prevent blue-light-induced retinal injury.

As mentioned, there are 4 types of dental curing lights. All of them are capable of achieving the blue wavelength that is intended for polymerization. Among the 4, the two most common are LEDs and halogens.

• Tungsten Halogen

One of the early dental curing lights is the tungsten halogen curing lights. Developed in the 1980s, they have been the replacement of UV lights by utilizing the blue wavelength. To generate the light, the halogen bulb needs to be energized.

The filament will then reach a temperature of 3,000 Kelvin or roughly 2,700 degrees Celsius. At this point, the visible light will then have a wavelength of 400 to 500 nanometers, which indicate the range for the blue light. With such a very high temperature, a powerful ventilating fan, which is already a part of the machine, is very much necessary.

So far, the technology is proven to be very useful until the emergence of a much more efficient generation of light such as the other 3 types. With the generation of great heat in halogen bulbs to achieve light, the ventilation fan is being used to its full potential just to cool down the operation, and thus, unnecessary noise from its mechanical action is also being produced in the process.

• Plasma Arcs

In the 1990s, there have been improvements in dental light-curing devices. A fluorescent bulb that contains plasma generates a light source of high intensity. According to the claims, within just 3 seconds, the resin composite material will be ‘cured.’

The bulb is a high-pressure vessel made from aluminum oxide. It contains xenon gas that is highly energized under a pressure of 150 psi. While the arc is made between 2 energized electrodes, the reflectors direct a focused beam. It is, without a doubt, effective, but the procedure costs a lot.

• Lasers

If you are familiar with argon lasers, they are usually used for medical practices. More commonly, you might have encountered that procedure in an eye clinic. Due to its effectiveness in generating such a focused light source, it is seen as effective for dental curing light.

The argon laser utilizes the noble gas ‘argon’ as the medium for the light to pass through. The light will become more concentrated and, thus, termed as ‘laser.’ However, using lasers can be too much on the budget for dental applications.

• LEDs Or Light-Emitting Diodes

Although lasers and plasma arcs are more efficient than tungsten halogen lights, they are very impractical, financially speaking. And here comes the newcomer, the light-emitting diode or LED. This semiconductor component is capable of emitting a wide spectrum of light without wasting energy in generating heat or having an expensive operating cost.

Since there is not much energy wasted as heat, small ventilation fans can be enough. Even with all the great things about LEDs, they too have limitations. They cannot generate more power compared to the other 3, but with numbers, that can be compensated.

They rely on chemical reactions for luminescence and might be prone to be busted if excessive energy is flown through the bulbs. Throughout the years, LEDs are still developing yet have now become the top light source both commercially and industrially. There is no wonder that even the development of new dental curing lights is gearing more towards the LED technology.

For curing the resin-based composites, it is important to use the right type of curing light. Upon installation of the resin-based composites, there are already particular instructions on the specification of lights to be used. Sometimes, the dentist recommends a specific product, but let’s discover what factors determine the choice for a dental curing light.

• Intensity

The more intense the light, the better is the chance of success in polymerizing. However, resin-based composites can have different requirements, and therefore, it will be better if the light source can be varied.

The unit ‘mW/cm2’ or ‘milliwatt per square centimeter’ is used when measuring the amount of light from a curing light. You can look for your resin-based composites’ intensity requirements and choose a light source based on that.

• Wavelength

One aspect or quantity of light that matters is the wavelength. The shorter they are, the higher their frequency is, and that relates to the ‘penetrating’ capability of the light. For an analogy, ultraviolet light and X-rays have shorter wavelengths than blue light, ergo, they have higher frequencies, and that explains why light at those spectrums passes through organic matter easily.

Some resin-based composites have a specific wavelength requirement in order for the light source to penetrate the material. For practicality, choose a product with a range of wavelength compatible with most resin-based products.  

• Polymerization Programs

The polymerization program refers to how the dental curing light is carrying out the polymerization. Apparently, the light will eventually reach its intended level of operation but getting it is crucial.

Why? Certain materials react to stress, and there is stress involved as light is being emitted. Here are the usual programs for polymerization.

• Ramp Up = progressively increasing the intensity
  • Staggered = alternating between the minimum and maximum intensity
  • Constant maximum power level

• Lamp Design

Technically, the 3 factors are enough. However, you need to consider the lamp design for the sake of the user’s comfort. Remember that the light source is used for curing the composite installed on the tooth or gums, and that involves hygiene which might affect the overall health.

A great design considers the ergonomics, weight, and tip angle. Make sure that the light can reach the back molar’s occlusal surface while the device can be easily cleaned off. Additionally, the tip rotation helps since an off-angle light will not be effective in curing than the one shining directly.

• Electrical Attachment

If you have older devices, you probably deal with the inconvenience of maneuvering the light curing device when the wire is on the way. The wireless card can help you solve that problem, but you might constantly be worrying about battery life. In this aspect, as you choose the right type, make sure you factor in how long you might be operating the light curing device.