Table of Contents
History of Lasers in Dentistry
The first laser was developed in 1960, and many other lasers and laser systems were created rapidly thereafter. Dental researchers began investigating lasers’ potential. For example, Stern and Sognnaes reported in 1965 that a ruby laser could vaporize enamel. In 1989, the first laser specifically designed for dental use became available. There are dozens of indications for use with various dental laser devices, and the clinical applications continue to increase. In the last two decades, there has been an explosion of research studies in laser applications.
Hard tissue applications
In hard tissue application, the laser is used for caries prevention, bleaching, restorative removal and curing, cavity preparation, dentinal hypersensitivity, growth modulation, and for diagnostic purposes.
Soft tissue applications
Soft tissue application includes wound healing, removal of hyperplastic tissue to the uncovering of impacted or partially erupted teeth, photodynamic therapy for malignancies, and photostimulation of herpetic lesions.
Types of Dental Lasers
Lasers are generically named for the material contained within the center of the device, called an optical cavity. One common for dentistry type of fiber laser is a fiber laser with carbon dioxide as a gaseous active medium. The other devices are either solid rods of garnet crystal combined with other elements, or solid-state semiconductor fiber lasers are called diodes, and the crystal fiber lasers are designed with acronyms such as Nd:YAG, and the like.
Each wavelength has a somewhat unique effect on dental structures, due to the specific absorption of that laser energy in the tissue. Lasers in dentistry can be categorized into three groups.
Diode and Nd:YAG lasers
Diode and Nd:YAG laser wavelengths target the pigments in soft tissue and pathogens, as well as inflammatory and vascularized tissue.
Carbon dioxide lasers
Carbon dioxide lasers interact with water molecules in soft tissue and vaporize the intracellular water of pathogens.
Erbium lasers
Erbium lasers (Er, Cr:YSGG and Er:YAG) interact with the water of soft and hard tissue. Erbium-doped lasers have excellent thermal relaxation, and very little collateral thermal damage occurs in tissues when proper parameters are followed. Erbium lasers can be used anywhere a scalpel is employed, including periodontal procedures, gingival contouring, biopsies, frenectomies, pre-prosthetic procedures, and the like.
There are two basic emission modes for dental lasers: continuous wave and pulsed. Continuous wave lasers emit energy constantly for as long as the fiber laser is activated: carbon dioxide and diode lasers operate in this manner. Nd:YAG, Er:YAG, and Er:YSGG devices operate as free-running pulsed lasers.