Study finds lack of research to support perio laser therapy

Soft-tissue lasers add no clinical value to the treatment of periodontal disease beyond what can be achieved using scaling, planing, and conventional surgical procedures, according to a literature review in the Journal of the Canadian Dental Association (April 2010, Vol. 76:2, a30).

But other research, and the evolving perception that periodontal disease is caused not by oral bacteria but by inflammatory cells that overreact to the presence of the bacteria, point to an issue that is not quite so black and white.

The integration of dental lasers into daily practice is being advocated as a "revenue booster" that offers patients a painless alternative to surgical treatment of periodontal disease and a benefit over traditional methods of therapy, according to Debora C. Matthews, D.D.S., M.Sc., chair of the department of dental clinical sciences at Dalhousie University.

"Although it may be true that dental lasers can increase revenue, statements relating to the effects of lasers appear to be based primarily on manufacturers' claims of laser efficacy rather than research data," she wrote.

In particular, Dr. Matthews noted, soft-tissue lasers are being promoted as an adjunct to, or substitute for, standard mechanical debridement of subgingival root surfaces and periodontal pockets.

"The use of lasers as an adjunct or alternative to conventional mechanical therapy is based on the claim that subgingival curettage and eradication of pathogenic bacteria will produce a sterile field, leading to elimination of periodontal pockets," she wrote.

Dearth of clinical research

But there is little scientific evidence to support these claims, Dr. Matthews noted. In fact, "there is a striking dearth of high-quality clinical research examining the effect of laser use in nonsurgical debridement to improve periodontal outcomes," she wrote.

Dr. Matthews came to her conclusions after reviewing the most current clinical evidence on the use of soft-tissue lasers in the nonsurgical treatment of periodontal disease, including three systematic reviews. One of the studies, commissioned for the American Academy of Periodontology (AAP), located 278 articles on the use of lasers in periodontics published before 2006 (Journal of Periodontology, April 2006, Vol. 77:4, pp. 545-564).

More recently, two systematic reviews identified 19 randomized controlled clinical trials, including 11 studies of the clinical effects of laser therapy compared with mechanical debridement in patients with chronic periodontitis (Journal of Periodontology, July 2009, Vol. 80:7, pp. 1041-1056; Journal of Clinical Periodontology, September 2008, Vol. 35:s8, pp. 29-44).

"None of these trials found laser therapy -- alone or as an adjunct to SRP [scaling and root planing] -- improved periodontal outcomes compared with SRP alone," Dr. Matthews wrote. "There were no statistically significant differences in microbial levels, attachment gain, bleeding indices, or pocket depth reduction in 10 of the 11 studies."

Inflammatory reaction

Dr. Matthews is not alone in her findings. Samuel Low, D.D.S., M.S., president of the AAP and a staunch supporter of the use of lasers for periodontal treatment, said that, from an evidence-based standpoint, Dr. Matthews' conclusions are correct. "I agree with the author that if you do SRP and you do it competently, I doubt seriously that the addition of a laser is going to assist in that process," he said.

And a January 2010 study in Dental Clinics of North America (Vol. 54:1, pp. 35-53) coauthored by Dr. Low that examined the current peer-reviewed evidence on the use of lasers in chronic periodontitis treatment also concluded there is little evidence to support the purported benefits of lasers in treating periodontal disease compared with traditional periodontal therapies. Because of the lack of well-designed clinical trials, clinicians using lasers for the periodontitis treatment "should expect limited clinical improvement in periodontal status," Dr. Low and his colleagues wrote.

Where the difference might be is the utilization of lasers in treating periodontal disease from a surgical standpoint, Dr. Low noted. In fact, he believes that as we gain a better understanding of the root causes of periodontitis, this could open new doors for lasers in the treatment of this disease.

"The AAP is moving more and more into the concept that it is inflammation that causes the destruction in gum disease, not the bacteria itself," he said. "It's like a bee sting: It is not the bee that kills you. It is your reaction to the sting."

In patients with periodontal disease, he noted, there is an inflammatory reaction -- an overreaction by the cells to enzymes in the bacteria. "So with the laser, if one removes some of the connective tissue that has these 'bad' inflammatory memory cells in it, it is conceivable -- we don't have this based on science yet -- that the posthealing response might be more positive than just cleaning roots and removing bacteria," he said.

Toward that end, a split-mouth, single-blind, randomized controlled clinical trial published by the Journal of Periodontology (April 16, 2010) concluded that a single application of a water-cooled Nd:YAG (neodymium-doped yttrium aluminum garnet) laser "significantly improves clinical signs associated with periodontal inflammation compared to treatment by SRP alone."

"There probably are still some things we do not know because lasers in dentistry are a very new frontier," Dr. Low said. "But one thing I know as a fact: Lasers are not going away. In my practice, if you give a patient a choice between a laser or a blade (for perio therapy), they jump on the laser. If your patients are walking away from surgery that is necessary to save their teeth, then you are doing them a service by offering the laser."

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