Judging the Efficacy of Laser Treatment

In her article on soft tissue lasers and nonsurgical periodontal therapy,¹ Dr. Matthews concludes “there is no evidence that any laser system adds clinical value over and above SRP [scaling and root planing] and conventional surgical treatment.” I challenge this conclusion based on the grounds that Dr. Matthews did not cite comprehensive reviews but instead employed selective references of systematic review articles. These systematic reviews, by definition, narrow their scope of references because they focus on a subset of an area of interest, such as nonsurgical versus surgical periodontitis treatments.

The conclusion that there is not even the slightest amount of evidence supporting the laser system’s value is biased, given the more than 20 years of research into the subject by Drs. Marshall Midda and Ray Yukna in the 1980s and 2000s respectively. A comprehensive review should have included the research authored by Ishikawa and colleagues in Periodontology 2000,² which concluded, “Laser treatments have been shown to be superior to conventional mechanical approaches with regards to easy ablation, decontamination and hemostasis, as well as less surgical and postoperative pain in soft tissue management.”

The discrepancy between the article by Dr. Matthews and the one by Ishikawa and colleagues likely stems from Dr. Matthews’ omission of an important paragraph from the article by Slot and colleagues³ which she references: “Several advantages of laser treatment over conventional methods include minimal cellular destruction and tissue swelling, hemostasis, increased visualization of surgical sites, sterilization of the wound site, reduced postoperative pain, and high patient acceptance.”

Presenting a more balanced article is essential for the advancement of this very important treatment, which could benefit many Canadians. Having used various laser devices as a practising clinician for 20 years, and having lectured and given seminars on clinical laser applications, I can speak with authority on the subject and can provide empirical and scientific evidence relevant to drawing a definitive conclusion.

Response from the Author

I thank Dr. Gregg for his interest in my article on the efficacy of lasers in nonsurgical periodontal therapy.¹ Certainly, there is evidence on the benefits of certain types of lasers for use in specific situations in clinical dentistry. The purpose of my article was not to discuss the use of lasers for surgical procedures or restorative dentistry. Rather, it was to present a narrative review of the best available clinical evidence for the use of lasers in a specific situation—that being nonsurgical periodontal therapy (i.e., scaling and root planing or mechanical debridement).

The paragraph Dr. Gregg quotes from the systematic review by Slot and colleagues² was taken slightly out of context. Indeed, there are studies showing that the Nd:YAG laser has bactericidal effects on periodontal pathogens. However, when taking into account the quantity and quality of all the clinical evidence, there is no support for the statement that Nd:YAG lasers are superior to traditional mechanical debridement, either alone or in addition to scaling and root planing. This could be, in part, because removal of the pocket epithelium (formerly known as gingival curettage) does not provide any significant clinical benefit.³

Providing the best care for our patients demands that we use the best evidence, that which is least biased in terms of study design, analysis and interpretation. Systematic reviews, such as those presented by Slot and colleagues,² Schwarz and colleagues⁴ and Cobb,⁵ are a useful tool for the clinician. They are a single summary of a number of research articles related to a specific clinical situation and take into account both quality and quantity of the best clinical evidence when drawing conclusions. They are not based on in vivo or histologic studies, because this form of evidence is not always directly applicable to clinical improvement.

Systematic reviews are not perfect. They too can be biased. However, when carried out according to established protocols, they are methodologically rigorous and reproducible. Systematic reviews should not serve as a proxy for clinical judgment, but can form part of a triad of clinical decision making, along with patient preferences and the dentist’s expertise and clinical judgment.