Low-level laser as an adjunct to non-surgical periodontal treatment-evidence limited


Studies in animals and in vitro have suggested that low-level laser therapy (LLLT) suppresses inflammation in periodontal tissue. However, results from clinical studies have given mixed results.

The aim of this review was to assess whether LLLT in combination with conventional mechanical debridement, provides any additional benefits over scaling and root planing (SRP) alone


Searches were conducted in the PubMed, Embase and Cochrane Library databases. Randomised controlled trials involving the use of LLLT as an adjunct to non-surgical periodontal treatment in patients with chronic periodontitis were considered. Two reviewers screed studies independently and risk of bias was assessed using the Cochrane Risk of Bias tool. Meta-analysis was conducted using a fixed-effects model.


  • 7 RCTs involving a total of 180 patients were included.
  • 3 studies were of parallel arm design a 4 of split mouth design.
  • 6 of the studies were considered to be at high risk of bias and 1 at medium risk
  • Meta-analysis showed that LLLT-mediated SRP demonstrated significant short-term benefits over SRP monotherapy at 1 month with
  • Improvement of the probing pocket depth; Mean difference = -0.40; (95%CI; -0.64 to -0.17; p = 0.0009)
  • Level of interleukin-1β in the gingival crevicular fluid, Standard mean difference= -0.77 (95% CI; -1.35 to -0.18; p = 0.01)
  • LLLT failed to show significant additional intermediate-term (3 and 6 mo) effects in terms of clinical parameters and alveolar bone density.


The authors concluded

Although LLLT is widely recommended for its biostimulatory and anti-inflammatory roles, it only showed additional short-term merits in reducing the pocket depth after conventional SRP. However, its intermediate-term effects were found to be non-significant. Its long-term adjunctive benefits remain unclear because of the substantial methodological weaknesses and the insufficient number of existing studies. Future RCTs with better study designs, adequate sample power and longer durations of follow-up are required to assess the effectiveness of LLLT as an adjunctive treatment strategy in patients with periodontal disease.


The reviewers have carried out a broad search of 3 major databases but have only been able to identify 7 small RCTs to address their question. The quality of the included studies is an issue and the authors include a good discussion of the main methodological issues with them and present recommendation for future research, including clarity over inclusion criteria and their clear reporting, sample size calculations, clear reporting of laser parameters and longer follow up periods.


Primary paper

Ren C, McGrath C, Jin L, Zhang C, Yang Y. The effectiveness of low-level laser therapy as an adjunct to non-surgical periodontal treatment: a meta-analysis. J Periodontal Res. 2016 Mar 2. doi: 10.1111/jre.12361. [Epub ahead of print] PubMed PMID: 26932392.

Other references

Dental Elf – 22nd Mar 2016 – Lasers for surgical periodontal treatment – insufficient evidence of effectiveness

Dental Elf – 21st Jul 2015 – Guideline: Nonsurgical treatment of chronic periodontitis

Dental Elf – 15th May 2014 – Review finds limited evidence for adjunctive use of the diode laser with non-surgical periodontal debridement


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Derek Richards

Derek Richards is a specialist in dental public health, Director of the Centre for Evidence-Based Dentistry and Specialist Advisor to the Scottish Dental Clinical Effectiveness Programme (SDCEP) Development Team. A former editor of the Evidence-Based Dentistry Journal and chief blogger for the Dental Elf website until December 2023. Derek has been involved with a wide range of evidence-based initiatives both nationally and internationally since 1994. Derek retired from the NHS in 2019 remaining as a part-time senior lecturer at Dundee Dental School until the end of 2023.

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