Lasers Shine a Light on Dentistry

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

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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.

Photo courtesy of BIOLASE Technology

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.