title: The effectiveness of low-level laser therapy as an adjunct to non-surgical periodontal treatment: a meta-analysis.
abstract: OBJECTIVE
  Although low-level laser therapy (LLLT) has been demonstrated to have a biomodulatory effect on periodontal tissue, no systematic review has exclusively addressed its effectiveness as an adjunct to non-surgical periodontal treatment. This study aimed to evaluate whether an additional benefit exists for the application of LLLT compared with scaling and root planing (SRP) alone.
  
  
  METHODS
  An extensive search was conducted in the Cochrane Library (Issue 8, 2015), PubMed (1997) and EMBASE (1947) before August 2015 for randomized controlled trials (RCTs). The bias risk was assessed with the Cochrane tool for risk of bias evaluation. A meta-analysis was performed using REVMAN 5.3.
  
  
  RESULTS
  After independent screening of 354 initial records, eight publications (seven RCTs) were included. However, six were rated as 'having a high risk of bias' as a result of major methodological weakness in 'allocation concealment' and 'blinding of key personnel'. Meta-analysis showed that LLLT-mediated SRP demonstrated significant short-term benefits over SRP monotherapy in the improvement of the probing pocket depth (p = 0.0009 at 1 mo; p = 0.03 at 2 mo) and the level of interleukin-1β in the gingival crevicular fluid (p = 0.01 at 1 mo). Nevertheless, LLLT failed to show significant additional intermediate-term (3 and 6 mo) effects in terms of clinical parameters and alveolar bone density.
  
  
  CONCLUSIONS
  These findings indicated that LLLT showed only short-term additional benefits after conventional SRP. Its long-term effects remain unclear due to substantial methodological weaknesses and an insufficient number of current studies. Future RCTs with better designs and longer follow-up periods are required to assess the effectiveness of LLLT as an adjunctive treatment strategy in patients with periodontal disease.
authors.affiliation: Faculty of Dentistry, the University of Hong Kong, Hong Kong SAR, China.
authors.forename: C
authors.initials: C
authors.lastname: Ren
authors.affiliation: Faculty of Dentistry, the University of Hong Kong, Hong Kong SAR, China.
authors.forename: C
authors.initials: C
authors.lastname: McGrath
authors.affiliation: Faculty of Dentistry, the University of Hong Kong, Hong Kong SAR, China.
authors.forename: L
authors.initials: L
authors.lastname: Jin
authors.affiliation: Faculty of Dentistry, the University of Hong Kong, Hong Kong SAR, China.
authors.forename: C
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Faculty of Dentistry, the University of Hong Kong, Hong Kong SAR, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Yang
mesh_terms: D003131:Combined Modality Therapy; D012534:Dental Scaling / Q000379:methods; D006801:Humans; D028022:Low-Level Light Therapy / Q000379:methods*; D010518:Periodontitis / Q000532:radiotherapy* / Q000628:therapy; D016745:Root Planing / Q000379:methods
keywords: chronic periodontitis; low-level laser therapy; non-surgical periodontal treatment; systematic review