Lasers in orthodontics

Dentistry, in all its neoteric era revolves around the techniques and procedures that are advantageous and patient friendly. Such a research led to the institution of light amplification and stimulated emission of radiation technique, both in medicine and dentistry. Lasers are currently being followed in all the specialties including orthodontics, wherein it has dramatically decreased the treatment timings, resulting in better outcomes along with pain reduction procedures, greater patient satisfaction and a superior practice.


Introduction
Lasers are finding their way into today's top orthodontic practices, aiding the doctors in managing usual soft tissue problems associated with patients in braces. Launching this technology safely and successfully depends largely on the doctor's commitment to doing it right. It is important to engage in training and developing systems for incorporating procedures into practice. Integrating these steps, greatly facilitates laser implementation and advances the orthodontist's expertise, confidence, and satisfaction.
History of the Laser: "LASER," an acronym for light amplification for stimulated emission of radiation, is a device for generating high intensity, evidently parallel beam of monochromatic electromagnetic radiation. The probability of stimulated emission was anticipated by Einstein in 1917.
Theodore Maiman 1 created a first operational laser in 1960, based on the work of Gordon in 1955 and Schawlow and Townes in 1958. A ruby laser emitting a brilliant red beam of light was constructed. Development of argon, carbon dioxide, and neodymium: yttriumaluminium-garnet (Nd:YAG) 2,3 lasers within 3 years from the construction of ruby laser occurred. These remain the most widely used lasers in dentistry and medicine till date. Soft lasers, which are based on the semiconductor diode devices, are compact, low-cost devices being used predominantly, are termed as lowlevel laser therapy (LLLT) or 'biostimulation'. 4 The probability of stimulated emission was anticipated by Einstein in 1917. 5

Fig. 1: Flowchart depicting types of lasers used in dentistry
Types of Lasers: There are about four types of lasers being used in dentistry today. Erbium Laser: This laser can be used on hard tissue 6 for cavity preparation or bone cutting, using short pulses of 50-100 microseconds. It can also be used on soft tissue, using longer pulses of 300-1000 microseconds. In this mode it can be used for periodontal procedures, gingival contouring, frenectomies, facial resurfacing or biopsies. The benefits of using this type of laser include minimal heat penetration, 7 rapid healing and minimal postoperative pain. However, these lasers are large and expensive and have significantly more capability than an orthodontist generally would use in everyday cases. Nd:YAG Laser: This was the first laser designed for dentists, and was introduced in 1990. A pulse laser with a wavelength of 1064nm, the Nd:YAG laser has the unique ability to penetrate deep into the tissue, 8 and can even stimulate fibrin formation, aiding in the coagulation of operative sites. This laser has been used in the periodontal field 9 for disinfection and debridement of periodontal pockets and the Laser Assisted New Attachment Procedure (LANAP). 10 CO2 Laser: Introduced in the 1970s, this laser has a wavelength of 1060nm and is highly absorbed by 11 water. It is very good at hemostasis but can be used on soft tissue only. It is useful for cutting soft tissue with reduced charring, and is used most frequently for biopsies. Sutures are seldom needed since hemostasis is exceptionally good. Diode Laser: Compact and affordable, this laser is used most frequently by orthodontists for soft-tissue management. The diode laser's wavelengths range from 805-1064nm, which means it can only be used on soft tissue. A wavelength of 940nm represents peaks for the absorption of laser energy by hemoglobin, oxyhemoglobin and water, making the 940nm diode laser very effective as an instrument to incise gingival tissue.
A diode laser uses heat as the energy source to incise the tissue, and it can be used quite effectively for frenectomies and photostimulation of the apthous and herpetic lesions. 12 It is also utilized in doing biopsies, canine exposure, gingival recontouring and gingivectomies. Minor charring is very common around the surgical site, but resolves within a three-to five-day window under normal circumstances. The light energy produced by a laser can have four different interactions with a target tissue. 13,14 Reflection, transmission, scattering, and absorption.

Orthodontic Clinical
Applications: Specific procedures include aesthetic gingival recontouring, soft tissue crown lengthening, exposure of impacted teeth, removal of inflamed and hypertrophic tissue, healing of wound 16 and frenectomies. Incorporating the use of lasers into orthodontic practice has been extremely productive on many levels. Placement of brackets more accurately and healing of exposed impacted teeth has significantly reduced treatment time and patients appreciate, the reduction of surgical complications and appreciate the way their smile has improved in a much lesser time.

Conclusion
Laser treatment enhances patient experience and saves considerable time.
The patient experience is very positive and in most cases only a topical anaesthetic is used and generally most patients report that they did not need to take any analgesics following the procedures. Incorporating laser technology could significantly benefit any orthodontic practice as an aid for adjunct procedures.