GENERAL LASER INFORMATION
GENERAL LASER INFORMATION
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888.203.3682
LASER BASICS
LASER = Light Amplification by the Stimulated Emission of Radiation
Electromagnetic Spectrum
Light is measured in wavelengths found along the electromagnetic spectrum. The enitire spectrum consists of a continuum that includes radio waves, microwaves, infrared light, visible light, ultraviolet light, x-rays, and gamma rays. Visible light is that portion of the electromagnetic spectrum that our eyes can perceive.
Every electronic wave exhibits its own unique frequency and wavelength associated with that frequency. As you can see, infrared light rays have longer wavelengths (and lower frequencies) than visible light, and gamma rays have much shorter wavelengths (and higher frequencies) than ultraviolet rays.
The most common unit used to express a laser's wavelength is a nanometer (nm). There are a billion nanometers in one meter (1nm = 1 x 10-9). Laser light ranges from the infrared (700 nm - 1mm), the visible (400 - 700 nm), and the ultraviolet (100 - 400 nm).
All but one of the relevant dental lasers are in the infrared section of the electromagnetic spectrum. The exception is the 532 nm KTP which is in the green (visible) section of the electromagnetic spectrum.
Each wavelength has a specific thermal output and specific tissue interaction that is 100% predictable. It is the specific thermal output (which increases as the wavelength gets longer) and specific absorption characteristics (tissue interaction) of each wavelength that determines the appropriateness of use for specfic medical and dental applications.
History
In 1905, Albert Einstein suggested that light was made up of a stream of energy packets called photons. Over the next decade, Einstein further developed his concept of photons, and in 1916 wrote a paper suggesting that when an excited atom encounters a photon that was released by an indentically excited atom, a photon of the same energy is released. This idea was considered odd, and at he time a situation that would allow this interaction between photons and atoms was rare - in fact, it wasn't until much later that scientists were able to artificially create an environment that consisted of identically excited atoms.
In 1954, Charles Townes and Arthur Schawlow invented the maser (microwave amplification by stimulated emission of radiation). The technology of the maser was very close to the laser, but it amplified wavelengths in the microwave section of the electromagnetic spectrum. One significant problem with the maser was the fact that the energy levels of the excited molecules (ammonia was the medium) would immediately fall to ground state, and as a result, the maser was incapable of continuous output. New systems needed to be designed that had more than two energy levels (thus continually maintaining a population inversion of atoms that can absorb and release energy).
In 1958, Townes and Schawlow published a detailed proposal to build an optical maser (later renamed the laser).
In 1960, Theodore Maiman created the first working laser. Maiman's laser was a "pink" ruby laser that was only capable of pulsed operation.
How Lasers Work
At the outset of any discussion on light (laser or not), it must first be noted that modern physicists believe that light can behave as both a particle and a wave, and that both views are simplistic explanations for a very complex phenomenon. Remember that we are talking about how light behaves and not what light is - in fact, low energy photons (on the electromagnetic scale) behave more like waves, whereas higher energy photons behave more like particles.
In an atom, electrons are found in various orbital levels surrounding the nucleus. an electron cannot occupy space between these levels, but it can jump from level to level as energy is either absorbed into or released from the atom. It is this controlled process of "exciting" atoms that is fundamental to generating laser light.
The concept of how laser light is generated is relatively simple, and there are three basic steps. First, atoms are stimulated and excited by an outward energy source, which the atoms absorb. Second, as the atom relaxes into its original state, the absorbed energy is released in the form of a photon (a light particle). And finally, this photon is trnasmitted onto tissue (or metal or any other substance that the laser is intended to affect).
Laser light is very different from normal light because of these three unique properties:
There are three basic components to any laser:
There are three types of transmission systems that dental lasers use to transmit energy onto tissue:
Safety Considerations
In addition to thermal effects on tissue, there can also be harmful photochemical effects when the wavelength of a laser is short (e.g., in the ultraviolet and blue section of the spectrum). However, lasers designed for medical use are located in the visible and infrared spectrum, and as a result there are never hazardous levels of radiation present.
It is widely accepted that the human eye is more vulnerable to radiation and injury than other tissue structures. As a result, both the patient and the practitioner should wear protective eyewear to avoid any reflected laser light from hitting the cornea.
Due to the high thermal output of laser light, pure oxygen should always be turned off in the area of laser operation. Additionally, despite the fact that nitrous oxide is diluted, it is commonly accepted that it should also be removed from the near vicinity of laser use.
Most lasers use gas and high energy. Under no circumstances should anyone open the casing on any laser unless specifically licensed and certified to perform repairs or maintenance on the laser.
Dental Laser Wavelengths
When looking at the spectrum of dental lasers, it is important to understand the characteristics of each wavelength - these characteristics determine the range of application on either soft or hard tissue.
Following is a brief discussion of each wavelength commonly used in dentistry:
Diode
The diode lasers at 810 nm and 980 nm are used primarily for soft tissue applications. Currently there is one manufactuer that promotes a 940 nm diode that is supposed to offer the benefits of both the 810 and 980 nm diodes. The 810 nm diode can also used for bleaching, but is not as effective as other systems currently available on the market. The diode lasers are good machines for trimming and reshaping soft tissue, are commonly used for sulcular debridement, and are occasionally used for excising fibromas and treating ulcers. Both the 810 nm and 980 nm diodes can be used for coagulation, however the 980 nm is better absorbed by water, and is generally considered to more gentle on intra-oral soft tissue structures due to the high water absorption characteristic.
The limitations of diode lasers include:
Nd:YAG
The 1064 nm Nd:YAG laser is also a soft tissue laser. The most important characteristic about the Nd:YAG is the fact that its greatest absorption is in dark pigmentation. As a result, the energy can travel through surface tissue into underlying tissue structures where it can cause a tremendous amount of damage that can't be seen (although newer machines are pulsed fast enough to avoid this transmission into deeper tissue).
This laser is generally positioned for periodontics, and can be effectively used for sulcular debridement. Because of its greater thermal output, the Nd:YAG laser has greater coagulation properties than the diode lasers. The Nd:YAG wavelength is absorbed by metal, so this laser cannot be used around implants.
Er:YAG
The 2940 nm Er:YAG (also called an erbium laser) is the only laser that will ablate hard tissue. The erbium laser is 100% absorbed in H2O and 100% absorbed in hydroxyappetite while haviing a maximum absorption depth of 0.10 mm. Although this laser is most appropriate for hard tissue applications, it is sometimes positioned as a soft tissue laser, too. This wavelength typically has poor coagulating properties, therefore most dentists who use an Erbium for soft tissue applications experience a high degree of frustration.
CO2
The CO2 laser is the best laser for soft tissue applications for several reasons. This wavelength has 100% absorption in water, approximately 93% absorption in hemoglobin, and approximately 86% absorption in melanin, for a net effect of approximately 98% in soft tissue. Consequently, the CO2 laser has a maximum penetration depth of 0.10 mm, which eliminates the risk of damaging underlying tissue structures.
Because the CO2 operates at 10,600 nm, it has the greatest thermal output and complete coagulation (It does not rely on a fiber optic to concentrate heat - the fiber optic becomes less comfortable for the patient). The CO2 is also the only wavelength that if pulsed fast enough can create a surgical incision the same width and depth as a scalpel. One problem traditionally inherent with a CO2 laser is that carbonization typically occurs due to the high thermal output. However this problem can be avoided if the emission is pulsed fast enough. If this is accomplished, absolutely no carbonization is present. (The Spectra DENTA is one of the few CO2 lasers on the market world-wide that can provide this performance.) In addition, this wavelength is reflected by metal so it is 100% safe working around implants.
Benefits of the Spectra DENTA CO2 Laser
Following are key benefits of the Spectra DENTA CO2 Laser:
LASER = Light Amplification by the Stimulated Emission of Radiation
Electromagnetic Spectrum
Light is measured in wavelengths found along the electromagnetic spectrum. The enitire spectrum consists of a continuum that includes radio waves, microwaves, infrared light, visible light, ultraviolet light, x-rays, and gamma rays. Visible light is that portion of the electromagnetic spectrum that our eyes can perceive.
Every electronic wave exhibits its own unique frequency and wavelength associated with that frequency. As you can see, infrared light rays have longer wavelengths (and lower frequencies) than visible light, and gamma rays have much shorter wavelengths (and higher frequencies) than ultraviolet rays.
The most common unit used to express a laser's wavelength is a nanometer (nm). There are a billion nanometers in one meter (1nm = 1 x 10-9). Laser light ranges from the infrared (700 nm - 1mm), the visible (400 - 700 nm), and the ultraviolet (100 - 400 nm).
All but one of the relevant dental lasers are in the infrared section of the electromagnetic spectrum. The exception is the 532 nm KTP which is in the green (visible) section of the electromagnetic spectrum.
Each wavelength has a specific thermal output and specific tissue interaction that is 100% predictable. It is the specific thermal output (which increases as the wavelength gets longer) and specific absorption characteristics (tissue interaction) of each wavelength that determines the appropriateness of use for specfic medical and dental applications.
History
In 1905, Albert Einstein suggested that light was made up of a stream of energy packets called photons. Over the next decade, Einstein further developed his concept of photons, and in 1916 wrote a paper suggesting that when an excited atom encounters a photon that was released by an indentically excited atom, a photon of the same energy is released. This idea was considered odd, and at he time a situation that would allow this interaction between photons and atoms was rare - in fact, it wasn't until much later that scientists were able to artificially create an environment that consisted of identically excited atoms.
In 1954, Charles Townes and Arthur Schawlow invented the maser (microwave amplification by stimulated emission of radiation). The technology of the maser was very close to the laser, but it amplified wavelengths in the microwave section of the electromagnetic spectrum. One significant problem with the maser was the fact that the energy levels of the excited molecules (ammonia was the medium) would immediately fall to ground state, and as a result, the maser was incapable of continuous output. New systems needed to be designed that had more than two energy levels (thus continually maintaining a population inversion of atoms that can absorb and release energy).
In 1958, Townes and Schawlow published a detailed proposal to build an optical maser (later renamed the laser).
In 1960, Theodore Maiman created the first working laser. Maiman's laser was a "pink" ruby laser that was only capable of pulsed operation.
How Lasers Work
At the outset of any discussion on light (laser or not), it must first be noted that modern physicists believe that light can behave as both a particle and a wave, and that both views are simplistic explanations for a very complex phenomenon. Remember that we are talking about how light behaves and not what light is - in fact, low energy photons (on the electromagnetic scale) behave more like waves, whereas higher energy photons behave more like particles.
In an atom, electrons are found in various orbital levels surrounding the nucleus. an electron cannot occupy space between these levels, but it can jump from level to level as energy is either absorbed into or released from the atom. It is this controlled process of "exciting" atoms that is fundamental to generating laser light.
The concept of how laser light is generated is relatively simple, and there are three basic steps. First, atoms are stimulated and excited by an outward energy source, which the atoms absorb. Second, as the atom relaxes into its original state, the absorbed energy is released in the form of a photon (a light particle). And finally, this photon is trnasmitted onto tissue (or metal or any other substance that the laser is intended to affect).
Laser light is very different from normal light because of these three unique properties:
There are three basic components to any laser:
There are three types of transmission systems that dental lasers use to transmit energy onto tissue:
Safety Considerations
In addition to thermal effects on tissue, there can also be harmful photochemical effects when the wavelength of a laser is short (e.g., in the ultraviolet and blue section of the spectrum). However, lasers designed for medical use are located in the visible and infrared spectrum, and as a result there are never hazardous levels of radiation present.
It is widely accepted that the human eye is more vulnerable to radiation and injury than other tissue structures. As a result, both the patient and the practitioner should wear protective eyewear to avoid any reflected laser light from hitting the cornea.
Due to the high thermal output of laser light, pure oxygen should always be turned off in the area of laser operation. Additionally, despite the fact that nitrous oxide is diluted, it is commonly accepted that it should also be removed from the near vicinity of laser use.
Most lasers use gas and high energy. Under no circumstances should anyone open the casing on any laser unless specifically licensed and certified to perform repairs or maintenance on the laser.
Dental Laser Wavelengths
When looking at the spectrum of dental lasers, it is important to understand the characteristics of each wavelength - these characteristics determine the range of application on either soft or hard tissue.
Following is a brief discussion of each wavelength commonly used in dentistry:
Diode
The diode lasers at 810 nm and 980 nm are used primarily for soft tissue applications. Currently there is one manufactuer that promotes a 940 nm diode that is supposed to offer the benefits of both the 810 and 980 nm diodes. The 810 nm diode can also used for bleaching, but is not as effective as other systems currently available on the market. The diode lasers are good machines for trimming and reshaping soft tissue, are commonly used for sulcular debridement, and are occasionally used for excising fibromas and treating ulcers. Both the 810 nm and 980 nm diodes can be used for coagulation, however the 980 nm is better absorbed by water, and is generally considered to more gentle on intra-oral soft tissue structures due to the high water absorption characteristic.
The limitations of diode lasers include:
Nd:YAG
The 1064 nm Nd:YAG laser is also a soft tissue laser. The most important characteristic about the Nd:YAG is the fact that its greatest absorption is in dark pigmentation. As a result, the energy can travel through surface tissue into underlying tissue structures where it can cause a tremendous amount of damage that can't be seen (although newer machines are pulsed fast enough to avoid this transmission into deeper tissue).
This laser is generally positioned for periodontics, and can be effectively used for sulcular debridement. Because of its greater thermal output, the Nd:YAG laser has greater coagulation properties than the diode lasers. The Nd:YAG wavelength is absorbed by metal, so this laser cannot be used around implants.
Er:YAG
The 2940 nm Er:YAG (also called an erbium laser) is the only laser that will ablate hard tissue. The erbium laser is 100% absorbed in H2O and 100% absorbed in hydroxyappetite while haviing a maximum absorption depth of 0.10 mm. Although this laser is most appropriate for hard tissue applications, it is sometimes positioned as a soft tissue laser, too. This wavelength typically has poor coagulating properties, therefore most dentists who use an Erbium for soft tissue applications experience a high degree of frustration.
CO2
The CO2 laser is the best laser for soft tissue applications for several reasons. This wavelength has 100% absorption in water, approximately 93% absorption in hemoglobin, and approximately 86% absorption in melanin, for a net effect of approximately 98% in soft tissue. Consequently, the CO2 laser has a maximum penetration depth of 0.10 mm, which eliminates the risk of damaging underlying tissue structures.
Because the CO2 operates at 10,600 nm, it has the greatest thermal output and complete coagulation (It does not rely on a fiber optic to concentrate heat - the fiber optic becomes less comfortable for the patient). The CO2 is also the only wavelength that if pulsed fast enough can create a surgical incision the same width and depth as a scalpel. One problem traditionally inherent with a CO2 laser is that carbonization typically occurs due to the high thermal output. However this problem can be avoided if the emission is pulsed fast enough. If this is accomplished, absolutely no carbonization is present. (The Spectra DENTA is one of the few CO2 lasers on the market world-wide that can provide this performance.) In addition, this wavelength is reflected by metal so it is 100% safe working around implants.
Benefits of the Spectra DENTA CO2 Laser
Following are key benefits of the Spectra DENTA CO2 Laser:
Radio Microwave Infrared Visible Ultraviolet X-ray Gamma Ray
Ultraviolet, Visible, and Infrared Sections of the Electromagnetic Spectrum
UV (100 - 400 nm) Visible (400 - 700 nm) Infrared (700 nm - 1 mm)
Dental Lasers:
532 nm
KTP
KTP
810, 940, 980 nm
Diodes
Diodes
1064 nm
Nd:YAG
Nd:YAG
2940 nm
Er:YAG
Er:YAG
10,600 nm
CO2
CO2
252 nm
Eximer Lasers
(Eye Surgery)
Eximer Lasers
(Eye Surgery)
481 nm
Argon
(Curing/Tissue Welding)
Argon
(Curing/Tissue Welding)
633 - 638 nm
Helium & Neon
Helium & Neon
2100 nm
HO:YAG
HO:YAG
| 1. | Laser light is monochromatic. Each photon released contains only one waveleghth, and each photon released is identical. For example, the wavelength of a CO2 laser is exactly 10,600 nm, and the wavelength of the Er:YAG laser is exactly 2940 nm. Because laser light is monochromatic, we can predict with 100% accuracy how each laser will interact with every type of tissue. |
| 2. | Laser light is coherent. Each photon moves in step with the others, and are "in phase" both in space and time. |
| 3. | Laser light is collimated. Laser light travels in a very tight beam that is strong and concentrated; there is little divergence of the beam as it travels away from the source. This allows the beam to be focused on a precise location. (Compare this to a flashlight that releases light in many directions.) |
| 1. | A medium which can be solid, gas, or liquid. These are the atoms that release the photons. |
| 2. | An exciter (or the pump mechanism) which is the outside energy source that acts upon the medium (e.g., light, heat, or radio frequency). It accomplishes starting the process of stimulated emission. Once a photon is released, it is the photon that causes another atom to release an identical photon. The process is amplified by the optical resonator (more photons that cause the release of yet more photons, etc.). |
| 3. | An optical resonator which amplifies the light produced from stimulated emission. This is a chamber that allows the reflection of light between two mirrors found on each end. As the photons travel up and down the tube at the speed of light, more photons are generated until the overflow exits one end of the tube and is transmitted onto tissue. |
| 1. | Articulating Arm. An articulating arm employs the use of mirrors in trasmitting the energy onto tissue. Generally, the handpiece is held away from tissue. This is the best transmission system because there is no energy loss in trasnission. There is also little risk of clogging the handpiece with coagulated blood or tissue. The only problem that arises with an articulating arm is when the mirrors are not aligned properly. |
| 2. | Fiber Optic. A fiber optic is probably the most common transmission method used in dental laser technology. The greatest problem with a fiber optic is the fact that the user needs close contact (approximately 1 - 1.5 mm from tissue) to actual fiber contact in order to effectively transmit energy. This often results in a buildup of blood and tissue coagulates on the end of the fiber(when working with soft tissue) which causes a block in the flow of energy. Another problem is the potential for the fiber tip to break off when working in a canal or pocket (typically when it comes in contact with granulation tissue found in deeper pockets). One benefit of a fiber optic tip is that the user can obtain coagulation with wavelengths that do not have a high thermal output due to a concentration of heat at the tip of the fiber when in direct contact with tissue. |
| 3. | Hollow Wave Guide. This is arguably the least efficient method to transmit energy onto tissue. The wave guide is highly susceptible to damage, and even the slightest damage can significantly diffuse and decrease the energy transmitted. this is an impractical transmission method especially when working on soft tissue with shorter wavelengths that do not have the thermal output to coagulate. |
| · | Diode lasers should not be used to incise to the level of the periosteum. |
| · | Hard tissue structures need to be avoided due to high thermal absorption. |
| · | Diode lasers operate in "contact mode" with the fiber which limits using beneficial treatment properties over a wider surface area. |
| · | The wavelength's low absorption in water (and high absorption in pigmented tissues) results in deeper penetration. |
| · | There is a higher risk of scarring due to deeper penetration into tissue. |
| · | Larger Procedures (due to size or more fibrotic tissue structures) typically result in slower healing and greater patient discomfort. |
| · | There is potential for the fiber tip to break off when working in a canal or pocket (typically when it comes in contact with granulation tissue found in deeper pockets). |
| · | Bloodless surgical field - true coagulation. |
| · | Sterilizing properties (ideal for infected tissue and minimizing post-op infection). |
| · | Seals nerve endings (little or no post-op pain). |
| · | Minimal penetration depth of 0.10 mm (faster healing, no scarring, great post-op comfort). |
| · | Safe around metal structures (e.g., implants). |
| · | Small footprint compared to other CO2 lasers. |
| · | Competitive price point. |
| · | Significant ROI (return on investment). |