Treatment of Periodontal Diseases With Laser: Assessing the Evidence

In 2017, Cobb published an extensive review of lasers and their use in the treatment of periodontitis.² He presented several axioms to the dental profession: (1) Therapeutic protocols or technologies must prove their case in the face of determined criticism. (2) Results must be reproducible. (3) Unbiased investigation can be significantly hindered by industry refusing to share proprietary procedures with the profession.

While benefits such as enhanced wound healing, photobiomodulation, hemostasis, and reduction of inflammation have been reported, the lack of high-level evidence, including randomized controlled trials (RCTs), cohort studies, and the inability to engage a meta-analysis approach, has significantly limited clinicians' ability to determine the value of laser usage in the treatment of periodontitis. Most reports on lasers have been lower-level case studies, technique articles, and opinion pieces. Thus, the debate lingers. This, however, is not uncommon in dentistry, as it has been estimated that only 7% to 8% of all dental treatment is truly evidence-based.³ Because of the lack of higher-level evidence related to dental lasers, Cobb suggested that clinicians interpret individual publications with caution.

Of the various laser wavelengths available, the diode laser has been the primary wavelength advocated as an adjunct to scaling and root planing (SRP) to purportedly reduce bacterial loads or sterilize the periodontal pocket. To date there is no RCT that supports this contention. A meta-analysis and evidence-based clinical practice guideline on adjuncts to SRP found that the clinical measures 3 to 6 months after diode application in conjunction with SRP did not demonstrate any long-term clinical advantage over SRP alone.^4,5 While laser technology-and the thought of having their periodontal pocket bacteria "eliminated"-may be appealing to patients, the overwhelming evidence points to this adjunctive practice as only increasing the cost of nonsurgical periodontal care significantly and needlessly.

In addition to diodes, other laser wavelengths (ie, CO₂, Nd:YAG, Er:YAG, and Er,Cr:YSGG) are used either in conjunction with or as a substitute for conventional periodontal surgery in horizontal and vertical defects. Due to the diversity of wavelengths and a lack of standardized protocols on vital outcome variables such as probing depth reduction (PDR) and clinical attachment level (CAL) gains or losses, it is virtually impossible to assess a laser's clinical significance. Additionally, some laser treatment protocols do not use traditional presurgical SRP, but instead treat the entire affected areas simultaneously. Therefore, the inclusion of sites treated without prior SRP within the assessment of laser clinical results can lead to the overstatement of the perceived benefit obtained using the combined therapy when not considering the benefit of SRP alone. Inclusion of sites that would likely respond to SRP alone shifts the clinical measures to appear better than they actually are when these sites are treated with lasers as an adjunct. This is a disturbing trend, because traditional SRP as a monotherapy is known to have great clinical benefits, especially in highly inflamed sites with horizontal bone loss.⁴

In 2018, the American Academy of Periodontology (AAP) conducted a best evidence consensus (BEC) on the efficacy of laser therapy used alone or as an adjunct to nonsurgical and surgical treatment of periodontitis.⁶ After a review of more than 475 articles, only 28 met the inclusion criteria for further review. The consensus was the body of evidence is lacking as it pertains to laser therapy with regard to most conclusions and clinical recommendations. Any statistical significance in PDRs or CALs was small and, at best, provided only modest clinical significance compared to traditional non-laser-assisted periodontal therapy. In addition to recommending standardized protocols and clinical outcome assessments, the BEC called for future studies to be compared against minimally invasive and regenerative treatments in adequately sized RCTs.

In an effort to strengthen the assessment of clinical relevance using lasers in the treatment of chronic periodontitis, the authors' institute, a practice-based clinical research network, set out to meet the BEC criteria for high-level evidence. The group designed a multicenter, blinded RCT in the surgical treatment of vertical defects using the Er,Cr:YSGG wavelength (ERL) in comparison to a minimally invasive surgical technique (MIST). Fifty-three subjects with 79 intrabony defects diagnosed with periodontitis stage III had SRP in all sites with probing depths (PDs) ≥6 mm followed by re-evaluation 6 weeks later for inclusion in the investigation. Subjects were required to have a persistent ≥6 mm PD in a site that also demonstrated a radiographic intrabony defect ≥3 mm in vertical depth and a defect angle of ≥25 degrees prior to being treated surgically. Following surgical care, periodontal maintenance therapy was provided every 3 months.

The 6-month results of this study, published in August 2020, illustrated that the use of ERL was not inferior to MIST in terms of clinical outcomes (ie, CAL gains and PDR), but was superior in patient-reported outcomes in terms of less postoperative side effects.⁷ This multicenter study was conducted by six different board-certified periodontists who had 0 to 15 years of experience using lasers. There was no difference in clinical outcomes among the investigators, and five of the six investigators required less treatment time for ERL defects compared to MIST defects.

This type of study has direct clinical implications for the practitioner, regardless of laser use experience, by highlighting an alternative surgical option that is effective in treating isolated chronic periodontal defects and requires less chairtime to complete with a lower percentage of patients reporting postoperative side effects. The clinician can therefore use non-inferiority analysis to consider ancillary benefits of the treatment tested. For example, in this RCT, the clinician could consider ERL when treating these defects when assessing extent (isolated versus multiple defects), postoperative course (less pain and swelling), minimally invasive alternatives (medically compromised, bleeding issues, cost, etc), and regenerative adjuncts (biologics and matrices). While the authors look forward to reporting on the 12-month clinical and radiographic findings, they believe this type of study exemplifies that which is needed to assess the efficacy of lasers in the treatment of periodontitis. It is long overdue that the dental profession demand higher-level investigations and citable publications from industry to advance technology in an evidence-based approach that benefits patients.

Equally imperative is the assessment of lasers in the treatment of peri-implantitis (PI), which is defined by the 2017 AAP Consensus World Workshop as a plaque-associated pathologic condition occurring in the tissue around dental implants, characterized by inflammation in the peri-implant mucosa and subsequent progressive loss of supporting bone.⁸ The prevalence of PI is reported as affecting 22% of all implants.⁹ Clinically, PI presents with ≥6 mm PD, ≥3 mm radiographic bone loss, and bleeding on probing.¹⁰ PI has demonstrated a lack of sustainable response to subgingival debridement alone, resulting in many adjuncts being employed to improve clinical outcomes.^11,12 Several systematic reviews and meta-analyses have been conducted on the use of lasers as well as other adjuncts in the treatment of PI. Many of these studies employed lasers as a monotherapy with little success. Similar to the aforementioned periodontitis analyses, these analyses have stated that the evidence is insufficient to draw definitive therapeutic conclusions regarding PI treatment modalities.^6,13-15

Given the absence of overwhelming evidence that any single therapy is predictably effective, some trends in results indicate that a comprehensive surgical approach may be required to achieve meaningful clinical results for PI-associated defects.^14,16 Recently, the author (DSC) and a colleague reported the 12-month results of a consecutive case series on 20 patients and 23 implants with PI defects treated using an Er:YAG laser for implant decontamination and granulomatous tissue removal along with regenerative therapy consisting of combinations of enamel matrix derivative, recombinant platelet-derived growth factor-BB, freeze-dried bone allograft, demineralized freeze-dried bone allograft, and the selected use of a resorbable collagen barrier.¹⁷ Significant PDR was achieved in sites ≥6 mm (mean initial PD of 8 mm ± 1.74 mm) with an average postoperative PD of 3.6 mm ± 1.33 mm, and 17 implants demonstrated radiographic evidence of >50% defect bone fill. The author emphasizes that higher-level investigations designed to assess the true clinical significance of this study's findings are essential to clarify the adoption of such approaches in the everyday treatment of PI.

Wang et al recently conducted a randomly controlled clinical trial investigating the combination of laser-assisted debridement with regenerative materials in PI vertical defects. They reported a positive trend with improved PDR and clinical attachment gains when laser debridement was employed in their regenerative protocol compared to mechanical debridement.¹⁸

When formulating clinical decisions with regard to using lasers alone or as adjuncts in the treatment of both periodontitis and peri-implantitis, the body of evidence leaves clinicians with a lack of clear direction. Generally speaking, the literature is insufficient (reflected in the relatively small number of subjects or defects) to show superiority of a device or technique over a comparable device or treatment. Because measurable differences may be small statistically, the broader patient benefit will likely influence a clinician's choice when considering minimally invasive therapeutics.

Donald S. Clem, III, DDS
Clinical Investigator and Board Member,
The McGuire Institute, Houston, Texas;
Private Practice, Fullerton, California

Rick Heard, DDS, MS
Executive Director, The McGuire Institute,
Houston, Texas; Private Practice, Victoria, Texas