Laser Dentistry
Implant Dentistry is a very fast growing dicipline of dentistry. It enhances mostly the surgical aspects of dentistry, but as new lasers are being developed, new applications are being discovered at a very fast pace. Today we are testing laser applications for Oral Surgery, Implant Dentistry, Endodontics, Periodontics and Esthetic Dentistry. New concepts like "biostimulation" can actually cover the whole gamut of Dentistry in some form or another.
History of Lasers
The word LASER is actually an acronym for Light Amplification by Stimulated Emission of Radiation. Albert Einstein is usually credited for the development of the laser theory. He was the first one to coin the term “Stimulated Emission” in his publication “Zur Quantentheorie der Strahlung”, published in 1917 in the “Physikalische Zeitschrift”.
There is a great deal of controversy surrounding the issue of giving credit to the first inventor of the laser. Theodore Harold Maiman is generally given credit for building the first working laser and operating it for the first time on May 16, 1960 at the Hughes Research Laboratory in Malibu, California. Maiman’s laser utilized a synthetic ruby crystal as a lasing medium for the generation of laser light. Gordon Gould, on the other hand, is often credited as the inventor of the laser. Gould was a doctoral student at Columbia University, working under Charles Townes, the co-inventor of the maser. Townes’ work gave Gould the foundation and inspiration to start building the first optical laser in 1958. Unfortunately, he did not file a patent on his invention until the following year, resulting in a rejection by the United States Patent and Trademark Office, since identical or very similar patents were already filed by Hughes Research Laboratories and Bell Laboratories.
Nevertheless, the first demonstration of a functioning visible laser was the ruby laser introduced by Maiman in 1960. This laser utilized a cylindrical ruby crystal as a lasing medium with a coiled quartz flash tube surrounding it. The flash tube was the energy source for the stimulated emission effect inside the ruby crystal. This laser produced millisecond pulses of coherent red light with a wavelength of 694 nm. This set the stage for a "snowball effect" which would lead to the development of many laser systems, which we utilize in healthcare today.
A little bit on Laser Physics...
First, we have to accept that we are surrounded by matter. It comes in various shapes and states. Our daily experience suggests that we can break any type of matter into smaller and smaller pieces. This subdivision of matter into successively smaller pieces (the practical and mechanical difficulties of such an endeavor set aside) will eventually come to a halt at the level of molecules. The molecular level sets the limit on mechanical breakdown of matter. If we were to break down the individual molecules of matter, we would have to apply either chemical or physical means. Once individual molecules are broken down further, we will eventually arrive at the atom, which is the smallest complete building block of matter.
Even atoms are composed of even smaller particles. These particles are in particular electrons, and protons and neutrons, which form the atomic nucleus. The electrons orbit the nucleus at a very great distance (relative to the atomic scale). Once it was discovered that the numbers of the protons, neutrons and electrons are related to each other, this relationship was utilized in the organization of the periodic table. The number of protons in the nucleus determines the actual element. In 1913, the Danish physicist Niels Bohr developed a slightly different atomic model and based on this model, he developed a famous set of postulates. One of his postulates states that "An electron can jump from one orbit to another. The energy difference between these orbital jumps is either carried away or supplied by a single quantum of light (called a photon), which has an energy equal to the difference in energy between the two orbits". This postulate is the foundation of light generation. An atom can move from the “ground state”, where all electrons are in energy-neutral orbits, to an “excited state”, where one or more electrons have jumped into a higher orbit (further away from the nucleus). This can only happen by absorption of energy, such as heat, electricity or light.
Laser light generation is based on this theory. Every laser has three basic elements: A pumping source (energy supply), a lasing medium (aka gain medium) and a resonator cavity. The pumping source can supply either light energy, electric energy or chemical energy to the lasing medium. The lasing medium is what defines the laser and its wavelength. It can be a gas, a solid crystal, a semi-conductor, a ceramic or a dye. This is where the spontaneous generation of photons happens by virtue of electrons moving from lower energy orbits to higher ones and back. Finally, the resonator cavity is the element, which amplifies the spontaneous emission process and finally emits the laser beam. Please follow the links above or in the side column to get a more detailed explanation of this process.
Laser Types used in Dentistry
As already mentioned, the type of laser is defined by its gain medium and the associated frequency of the beam. The following are the most commonly used lasers in dentistry (each of which will have a detailed description under their individual links):
- Diode Laser
- Nd:YAG Laser
- Carbon Dioxide Laser
- Er:YAG & Er,Cr:YSGG Laser
- Argon Laser
Applications of Lasers in Dentistry
Applications for lasers in dentistry grow at a rapid rate, however, the following applications are being used today (again, each of these applications will have a detailed description under their individual links):
- Tissue Surgery
- Bone Surgery
- Photosterilization
- Biostimulation
