LASERS FOR USE IN DENTISTRY

Lasers were first developed in the 1960s, and research into their applications in dentistry began soon thereafter. Early lasers were continuous wave devices with noncontact delivery that were found to be too hot for practical dental use. Of these early devices, CO2 lasers were developed further and had limited use for soft tissue excision, primarily by oral surgeons. In the early 1980s, short-pulsed, fiber-optic contact delivery laser technology was developed. Neodymium:yttrium-aluminum-garnet (Nd:YAG), erbium:YAG (Er:YAG), and erbium-chromium:yttrium-scandium-gallium-garnet. Currently, there are 20 specific indications for use of a variety of dental lasers. These applications have been reviewed for safety and effectiveness following the US Food and Drug Administration (FDA) 51 0 (k) clearance for market mechanism. Specific laser devices are cleared for a number of soft tissue applications, including intraoral soft tissue surgery (ablating, incising, excising, coagulating), sulcular debridement, treatment of aphthous ulcers and herpetic lesions, removal of coronal pulp and pulpotomy (adjuncts to root canal procedures), and coagulation of extraction sites. Hard tissue applications include caries removal, cavity preparation, selective caries removal in enamel, enamel roughening, tooth preparation to obtain access to the root canal, root canal cleaning, and root canal preparation, including enlargement, apicoectomy, bone cutting, shaving, contouring, and resection. Miscellaneous uses of lasers include curing of composite materials, removal of composite filling materials (not amalgam), and softening gutta percha. Lasers also are used as an aid in diagnosis of dental caries, illumination of caries detection and endodontic orifice location, and blood flow measurements. Clearly, no one device can accomplish all of these practical dental uses. Generally, a specific laser device is maximized for diagnosis or for use in soft or hard tissues. It is common to find lasers that are good for use in soft tissues with some hard tissue applications, and other lasers that are good for hard tissue with some soft tissue applications. Research is ongoing in the areas of caries prevention using lasers to change the structure of enamel. Research also is progressing in the area of optical coherence tomography for the nondestructive imaging of enamel and dentin to determine lesion progression over time. Exciting developments are occurring in the area of laser use in periodontal therapy for the removal and coagulation of the sulcular soft tissues and in the future for the selective removal of calculus on the tooth surface. There has been continued growth in this new and maturing field in dentistry. The profession can review the substantial scientific evidence available in the field, including at least two texts, and a large amount of information is available through organized dentistry. The standard for practitioners who use lasers is successful completion of a recognized standard proficiency course according to a defined and accepted curriculum. This Critical Appraisal focuses on the most used dental laser applications and the clinical trials conducted to support their safe and effective use.