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Laser in dentistry
The term LASER is an acronym for „Light Amplification by the Stimulated Emission of Radiation‟. As its first application in dentistry by Miaman, in 1960, the laser has seen various hard and soft tissue applications.
- In medicine for laser surgery and various skin treatments
- In Dentistry, a precise and effective way to perform many dental procedures. The potential for laser dentistry to improve dental procedures rests by allowing for treatment of a highly specific area of focus without damaging surrounding tissues.
- Lasers are special because they allow us to control light in new and important ways.
HISTORY
- Dental research began in 1963 at university of California at Los angeles school of dentistry, with investigators Stern and Sognnaes.
- RUBY LASER: - 1st laser constructed by Maiman - Emitted light of 0.694µm. - reported : - development of cratering and glass like fusion of enamel - penetration and charring of dentin(500-2000J/cm²) (Stern, 1964)
- In 1974, Stern observed resistance to acid penetration into enamel, suggesting role of laser in caries prevention.
- In 1965 – Taylor and Associates reported extensive hemorrhagic necrosis and disruption of odontoblastic layer.
- CO2 laser: 1970 - more effective for hard tissues as its wavelength of 10,600 nm is well absorbed by enamel. High affinity for hydroxyapatite
- In 1984, Melcer et al reported successful t/t over 1,000 patients in clinical trials of caries removal and in1987,concluded that laser could induce secondary dentin formation and sterilization of dentin and exposed pulp.
- Neodymium laser: - 1974, Yamamoto and Ooya in Japan - Determined as an effective tool for inhibiting the formation of incipient caries both in vivo and vitro.
- In 1995 FDA cleared a laser device for gingival surgery
- On May 7, 1997 FDA cleared the use of laser in treatment of tooth decay and in 1998 October , given clearance for use in children
COMPONENTS OF LASER
- An optical cavity: - 2 parallel mirror placed on either side - Mirror(M1) is totally reflective and other Mirror(M2)
- Laser medium: - suspended as a gas, a liquid, a solid sate - homogenous population of atoms or molecules pumped up to the excited state
- A pump energy source
- Cooling system
APPLICATIONS OF LASERS IN DENTISTRY
- Diagnosis by Detection of pulp vitality
- Doppler flowmetry
- Exposure of unerupted and partially erupted teeth
- Laser fluorescence- Detection of caries, bacteria and dysplastic changes in the diagnosis of cancer
- Hard tissue applications
- Caries removal and cavity preparation
- Re-contouring of bone (crown lengthening)
- Endodontic (root canal preparation ,sterilization and Apicectomy)
- Laser etching
- Soft tissue applications like Laser-assisted soft tissue curettage and periapical surgery
- Bacterial decontamination
- Gingivectomy and Gingivoplasty
- Gingival retraction for impressions
- Implant exposure
- Biopsy incision and excision
- Treatment of aphthous ulcers and Oral lesion therapy
- Coagulation / Hemostasis
- Tissue fusion - replacing sutures
- Laser-assisted flap surgery
- Removal of inflamed, hypertrophic tissue, and miscellaneous tissue removal
- Frenectomies
- Removal of root canal filling material and fractured instrument
- Softening gutta-percha
- Removal of moisture/drying of canal
TYPES OF LASER
Lasers used in dental practice can be classified by various methods:
- According to the lasing medium used, such as, gas laser and solid laser;
- According to tissue applicability, hard tissue and soft tissue lasers
- According to the range of wavelength
MOST COMMONLY USED AND IMPORTANT LASR IN DENTISTRY
Carbon dioxide Laser
- The CO2 laser wavelength has a very high affinity for water, resulting in rapid soft tissue removal and hemostasis with a very shallow depth of penetration.
- Disadvantages of the CO2 laser are its relative large size and high cost and hard tissue destructive interactions.
Neodymium Yttrium Aluminum Garnet Laser
- The Nd: YAG wavelength is highly absorbed by the pigmented tissue, making it a very effective surgical laser for cutting and coagulating dental soft tissues, with good hemostasis.
- Nd: YAG laser is used for nonsurgical sulcular debridement in periodontal disease control
Erbium Laser
- The erbium „family‟ of lasers has two distinct wavelengths, Er, Cr: YSGG (yttrium scandium gallium garnet) lasers and Er: YAG (yttrium aluminum garnet) lasers.
- The erbium wavelengths have a high affinity for hydroxyapatite and the highest absorption of water in any dental laser wavelengths.
- Consequently, it is the laser of choice for treatment of dental hard tissues.
- Erbium lasers can also be used for soft tissue ablation, because the dental soft tissue also contains a high percentage of water
Diode Laser
- The active medium of the diode laser is a solid state semiconductor made of aluminum, gallium, arsenide, and occasionally indium, which produces laser wavelengths, ranging from approximately 810 nm to 980 nm.
- All diode wavelengths are absorbed primarily by tissue pigment (melanin) and hemoglobin.
- Conversely, they are poorly absorbed by the hydroxyapatite and water present in the enamel.
- Specific procedures include aesthetic gingival re-contouring, soft tissue crown lengthening, exposure of soft tissue impacted teeth, removal of inflamed and hypertrophic tissue, frenectomies, and photostimulation of the apthous and herpetic lesions
| Laser | Wavelength (nm) | Wavelength Emission | Areas |
|---|---|---|---|
| Argon (Ar) | 488 | Continuous wave | Soft tissue |
| Nd (YAG) | 1064 | Free running pulse emission | Soft tissue |
| Diode | 800-830/904/980 | Continuous wave Free running pulse emission |
Soft tissue |
| Erbium (Er) | 2780 - 2940 | Free running pulse emission | Osseous tissue Enamel Dentin Cementum |
| CO2 | 10 600 | Continuous wave | Soft tissue |
MECHANISM OF ACTION
Laser light is a monochromatic light and consists of a single wavelength of light. It consists of three principal parts
- An energy source.
- Active lasing medium.
- And two or more mirrors that form an optical cavity or resonator.
For amplification to occur
