Lasers Shine a Light on Dentistry

Written on 03/25/2018
Masoud Abu Zant

Lasers have revolutionized medicine and now they're beginning to blaze a new trail in dentistry

The best way to predict the future is to create it and lasers are beginning to offer some interesting alternatives in dentistry. Lasers constitute “cutting-edge” technology which can be used to help 

detect dental disease in its earliest stages, find tumors and perform both surgical and non-surgical procedures on the soft tissues of the mouth. And they do it with less pain and bleeding. They can even prepare small cavities for fillings by vaporizing decay often without a shot of anesthesia (numbing the teeth), or a drill.

Since May 1960 when Theodore Maiman demonstrated the first working laser at Hughes Research Laboratories, laser technology has spawned a multi-billion dollar industry. Lasers now affect everyday life and are in widespread use: in optical storage devices (which store computer data); spectrometers (which by color analysis detect and identify even the tiniest particles from tumors to explosives); CD and DVD players in personal computers and even bar code readers in your supermarket use laser technology. Lasers are used industrially for steel cutting; by the military for target identification and illumination for weapons delivery. And of course lasers today are used extensively in medicine for ophthalmology (eyes), internal surgery, dermatology (skin) and oral health to name but a few applications.

What Really is a Laser?

Today at the dawn of the 21st century there are a variety of dental uses for lasers, from diagnosing cavities to the removal of gum and tooth structure to treat disease. Dental laser procedures are minimally invasive and can result in less tissue removal, less bleeding and less discomfort for patients after surgery. But what really is a laser?

The word “laser” is an acronym for “Light Amplification by Stimulated Emission of Radiation.” Lasers produce an intense and narrow beam of light of one single wavelength. Ordinary “white” sunlight by contrast, is a continuum of light of many wavelengths corresponding to the colors of the visible spectrum or rainbow, plus the infrared (heat) and ultraviolet wavelengths that sandwich them. Sunlight passing through a prism separates into its component colors; laser lights however are a single color.

Lasers for Medical Uses — Not “All” Smoke and Mirrors

To try to put it simply, a medical laser device includes: a source of electricity; mirrors to direct the beam; a crystal, gas, or set of semiconductors that when stimulated emit specific wavelengths of light, and fiber-optics that deliver the light energy. When used for medical diagnostics or procedures, the material that produces the light determines the specific wavelength properties of the laser and therefore what it can do in the human body. Lasers have revolutionized medicine and now they're beginning to blaze a new trail in dentistry.

A New Trend in Dentistry

Since the Food and Drug Administration (FDA) first granted marketing clearance for soft tissue surgery in 1991, the acceptance and use of lasers for dental procedures has continued to blossom. Dental laser usage falls roughly into three categories: disease diagnosis; soft tissue procedures (gums, lip and tongue) and hard tissue procedures (enamel, dentin or bone). The first use of dental lasers was for soft tissue treatment — certain types of gum and other soft tissue plastic surgery (reshaping procedures), biopsies (tissue testing) and more recently removal of benign and malignant lesions. This was followed by the approval of the first hard tissue applications (in 1997), such as decay removal and cavity preparation of enamel and dentin of the teeth. More recently they have been approved for bone re-contouring around the teeth and jaws. The most recent FDA clearance involves the use of lasers for the detection of both disease and health in tissues.

Early Adopters of New Technology

Dental lasers were introduced soon after their use as medical devices. In the 1990s, improvements in the pulsing of lasers and fiber-optic delivery systems created an upsurge in general dentists' usage of laser technology. According to a survey published by the American Dental Association in 2000, less than 10 percent of dentists surveyed were using lasers; that number has continued to rise. Predicted in a 2002 survey of dentists, indications were that after a year or more, 14 percent of dentists planned to purchase a laser for hard tissue and 10 percent for soft tissue applications. Each year more dentists obtain training and education in laser use and with this training, the number of dentists who offer laser treatment to their patients continues to grow.

Lasers in Dental Diagnosis

As diagnostic tools, lasers are being used to aid in the detection of dental disease in earlier stages than traditional methods. “Laser fluorescence” diagnostic lasers are very effective in diagnosing pit and fissure decay, the tiny areas in the biting surfaces of teeth where a traditional dental explorer (a needle-like pointed instrument) cannot reach. The optical properties of the bacteria in decayed teeth produce fluorescence, a glowing light which can be picked up by a laser detector. They are an excellent complement to oral examinations aiding in identification of caries (tooth decay) that might be missed by visual inspection alone. They also allow teeth to be monitored from one visit to the next, to determine if decay is “arrested” or “progressive” and therefore at what point treatment is truly needed.

Lasers can also aid in the detection and localization of dental calculus beneath the gums. Calculus (tartar) is hardened or calcified bacterial plaque that sticks hard to the teeth. Finding and removing this calculus is one of the goals of periodontal (gum) therapy.

Most recently, lasers have been developed which “fluoresce” healthy oral soft tissue. By identifying areas that fluoresce (glow) and those that don't, lasers are being used as a tool in detecting oral cancer at very early stages and are an aid in the detection and localization of abnormal tissues. Occasionally tissues become “dysplastic” (dys-altered, plasia-growth), or pre-cancerous, or worse yet, cancerous. Because of their precision, lasers are very useful for removing tissue close to the margins or edges of where diseased tissue meets healthy tissue. This precision and minimally invasive approach is particularly useful in determining these boundaries and exactly where to remove or excise unhealthy tissue, whether benign or malignant.

Star Trek Surgery

Research has shown that lasers are minimally invasive and involve less tissue removal than conventional methods. Following relatively painless removal of tissue, lasers also act by sealing off blood vessels and nerve endings so that there is less bleeding and pain. Inflamed watery tissue, like diseased soft tissue, absorbs dental laser energy, which doesn't penetrate very deeply. This vaporizes surface cells leaving a painless residue of carbon, called “char.” Left in place it serves as a biological dressing to aid in healing. This has proved advantageous in aiding clotting for bleeding sites after tooth extraction. The downside however, is that this tends to slow down healing.

Lasers are now being used in the treatment of periodontal (gum) disease to clean or “debride” unhealthy gum tissue. When gum tissue becomes detached from the teeth causing “pocket formation” (just like a pocket in your coat or shirt), this allows the formation of bacterial plaque and calculus which not only causes, but also perpetuates periodontal pockets. Combined with bacteria and calculus from the root surface, laser removal of the diseased lining of the periodontal pocket is showing promise in promoting new attachment and healing.

Lasers are quite successful in “soft” tissue removal for such procedures as gingivectomy (gingival – gum, ectomy – removal) and gingivoplasty (plasty – reshaping), primarily for esthetic purposes. Soft tissue lasers are excellent for frenectomy removal of a “frenum” — a small fold of tissue that secures or restricts motion. In some cases excessively large fronds of connective tissue cause separation of the upper front teeth, or under the tongue causing “tongue-ties.”

They can also be used to seal painful “aphthous” ulcers commonly known as canker sores which in some unfortunate people are large, painful and recur frequently; likewise for some sufferers of cold sores on the lips, caused by the Herpes virus HSV1. Work is also being done on the use of lasers as an adjunct to root canal treatment, in removing diseased tissues of the pulp, housed in the root canal system within the teeth.

Time to Put Down the Drill?

Lasers in many hard tissue dental applications (tooth enamel, dentine and bone) eliminate the need for the dental drill, thus relieving patients of the noise and vibration that can be disturbing and uncomfortable. They're also quite precise in the amount of tissue they remove, ideal for selective removal of early enamel caries (decay) and small cavities. Lasers have been shown to be less invasive and less destructive then the dental drill, saving patients' tooth structure. For larger cavities, lasers are a bit slower than conventional methods, which makes them inefficient. A dentist can prepare a small cavity for a filling by vaporizing the decay using a laser that passes through a fiber which is connected to a hand-piece just about the size of a pencil. Laser light is also useful as an aid in hardening composite resin (a common tooth colored filling material) and sometimes to help activate tooth whitening chemicals.

Most recently, lasers are being used for bone surgery, during periodontal (gum) surgery for re-contouring and removal of bone and for uncovering “impacted” wisdom teeth that need to be removed.

The science surrounding dental lasers continues to support their many current uses and shows promise for future applications of lasers in dentistry.

To be Fair

Lasers also have some disadvantages. Studies show laser procedures take longer than traditional methods. Lasers cannot be used on existing amalgam fillings because of the potential mercury exposure and the heating of metal restorations (fillings and crowns), which runs the risk of tooth damage. As yet there is no single laser to handle all the dental uses, however many dental laser systems have multiple dental applications. In addition, the cost of laser equipment compared to traditional equipment is relatively high.

Continuing development and research in the field of dental lasers will ensure that dentistry provides the best care for our patients. The science surrounding dental lasers continues to support their many current uses and shows promise for future applications of lasers in dentistry.

Training

Dentists and dental hygienists who use lasers and dental assistants who set up and monitor lasers, need specific training in safe laser use. Any laser can harm thin tissue, if used with too much power or for too long a period of time, so training is important. The Academy of Laser Dentistry is an international professional membership association of dental practitioners and supporting organizations dedicated to improving the health and well being of patients through proper use of laser technology. The Academy actively supports education and research through its certification programs, publication, meetings and additional activities. The Academy of Laser Dentistry supports certification of practitioners who use lasers in accordance with the Curriculum Guidelines and Standards for Dental Laser Education. These guidelines are the internationally recognized standard for dental laser use. They establish standards of education in the use of lasers in dentistry and define standards for the demonstration of competency in the safe and effective use of lasers by dental professionals.