Low Level Laser (Light) Therapy & Adult Periodontal Disease:

Dr Mark Cronshaw

Photobiomodulation (PBM) is an accepted evidence based therapy for some medical conditions including musculoskeletal pain, rheumatoid arthritis and oral mucositis. The expanded knowledge base on the physiology and biochemistry of the inflammatory cascade and its modulating factors have opened up the possibility of additional clinical pathways to explore in the search for further effective tools to eliminate inflammation and the associated destructive sequence in the periodontium.

 

Periodontal disease is a highly complex multifactorial condition and achieving resolution can be difficult. Conventional approaches have limitations and the requirement for an initial intensive and meticulous intervention combined with a life-long commitment to re-care is an issue for many patients. Lasers generically have many intrinsic interesting and useful properties. For instance, there is the potential for producing different results depending on dose.  Laser tissue interaction can range in product from biochemical and biophysical promotion of healing and the selective suppression of the inflammatory cytokine cascade through to surgical ablation of diseased tissues and the photothermal destruction of pathogens. Low intensity laser irradiation has been suggested as an adjunctive therapy to modify the cytokine cascade away from a reactive pro inflammatory locally destructive process to an anti-inflammatory cycle.   

 

The potential systemic benefits associated with this type of laser photo-therapy has been proposed as a possible mechanism for both reducing risk and affecting patient morbidity. Advocates for low intensity laser therapy propose that by use of so called photo-medicine there may be a reduced need for costly drugs with a lower risk of complication such as allergy or immunosuppression.

 

 

Low levels of laser energy are associated with a range of anti-inflammatory and pro-healing regulatory events. The incoming red end of the spectrum photonic energy is absorbed within the intracellular mitochondria by cytochrome C oxidase which in a stressed or hypoxic cellular state maybe bound to nitric oxide (NO). The incoming photonic energy decouples the NO resulting in a dramatic upswing in adenosine triphosphate (ATP) production. ATP is an important intra and intercellular modulator of cellular metabolism. Aside from energising the enzymic processes of the cell it is a significant modulator of gene expression. Karu has suggested that ATP may influence the expression of 110 genes within fibroblasts involved in 10 key processes. In addition PBM results in the formation of reactive oxygen species as well as modulating other aspects of cellular physiology such as membrane stability and the release of calcium ions and nitric oxide. The shift from suboptimal anaerobic acid producing cellular activity to a more alkaline and highly energised state results in increased cellular activity, cell division and growth as well as an increase in resistance to apoptosis

 

The resultant effects of PBM are wide ranging from vasodilatation and analgesia, improved lymphatic drainage and angiogenesis, to the activation and inactivation of specific cytokines which are central to the inflammatory process. Exposure to the correct dose of low level of laser energy can have a profound anti-inflammatory effect due to the up regulation of specific antagonists to interleukin-1β and TNF-α. These are key pro-inflammatory cytokines which in turn stimulate the release of PGE2 and modulate the transcription factors for nuclear factor κ B which results in osteoclast activation.   

 

Due to the potential for enhanced healing and reduced inflammation plus the ability to modulate the key cytokines involved in the destructive processes of periodontitis there has been a high level of interest in the potential benefits of PBM in the management of PD. Studies by Aykol et al and Qadri et al measured a statistically significant improvement in PPD, CAL and gingival inflammation in test groups treated with the low level Diode laser at a dose in the range 2-5J/cm2 In vitro and in vivo animal studies demonstrate that there are effects on the expression of IL-1, IL-6, IL-8 and TNF-α all of which are suppressed by PBM. In consequence PBM could prove of value in promoting healing and reducing inflammation as well as alleviating post-operative pain. The clinical studies of Aykol and Qadri however show only a small improvement in clinical parameters and the adjunctive value of this interesting treatment strategy have yet to be proven.

 

The potential for lasers to modulate the cytokine cascade towards an anti-inflammatory pathway was the subject of an interesting paper by Pesevska et al in a human histology study. The outcome clearly demonstrated a marked reduction in TNF-α in human papillae biopsies post laser irradiation. TNF-α is a key cytokine involved in the destructive histopathological sequence that cumulates in bone loss.

 

Pesevska et al used 80 patients in a parallel study divided into four groups. The measured clinical parameters were taken by two calibrated blinded periodontists and the choice of subjects for excisional papilla biopsy were randomly assigned. The results demonstrated a highly statistically significant change in TNF-α in the laser test subjects. The test group given a series of ten daily Diode laser treatments achieved the optimum results. The positive outcome of the therapy is very promising however this is a short term study. The researchers in this elegant study set out well defined boundaries with good scientific controls and a clear idea of the test subject. The laser parameters are presented in a well presented table and there is sufficient information to permit later researchers to either repeat the study or use the template for further investigations.

 

Turning this interesting study into something clinically applicable however takes some careful consideration. TNF-α forms in response to LPS stimulating a cell mediated immune response to a bacterial challenge. If there is a failure to eliminate the bacterial challenge then the intervention with the laser is bound to fail. There would in this event be at best a short term effect, as more TNF-α is manufactured in response to a continued or recurrent bacterial challenge. To translate this reported adjunctive use of low level laser therapy to a treatment protocol with a demonstrable long term clinical gain has yet to be determined.

 

The potential benefits of photo medicine via laser biomodulation are presently one of the aspects of laser use which are attracting a high level of current interest within the dental laser community. To date however the merits of the use of lasers in this respect has been shown to be only of marginal and temporary clinical benefit. Perhaps in conjunction with stem cell research and the selective use of tissue growth factors, PBM is an area which may in the fullness of time  evolve into a routine clinical measure.

 

Following the pioneering studies of Mester 50 years ago we now have however a very substantial scientific literature and a highly developed appreciation of many aspects of laser and light tissue interaction. The specifics of the photochemical processes involved are complex and involved and it is not the intention to cover these in full here as there are some excellent relevant articles by  acknowledged International authorities on the subject . At the end of this article is a suggested primer reference list for what has become a very large and rapidly expanding literature.

 

 

Future Trends:

 

 

Current efforts to incorporate photomedicine into periodontal care are attempts to capitalise on the existing evidence base that shows the potential for some improvements in clinical indices and a reduction in the histochemical markers associated with inflammation. A dual wavelength concept has evolved amongst practising laser clinicians of using erbium lasers for surgery and diode or neodymium lasers for photobiomodulation. Although there are many anecdotal clinical reports of positive clinical outcomes the evidence base of this approach currently is weak and in need of further studies. In recognition of the proven potential for phototherapy in reducing inflammation, promoting healing as well as reducing pain and post operative sensitivity the adjunctive incorporation of photomedicine into periodontology is inevitable. The issues remain however of establishing agreed evidence based clinical protocols. 

 

 

 

References:

 

  1. Mester E, Szende B, Spiry T, Scher A. (1972): “Stimulation of wound healing by laser rays”. Acta Chir Acad Sci Hung. Acta Chir Acad Sci Hung: 315–324

     

  2. Whelan HT, Houle JM, Whelan NT. et al. (2000): “The NASA Light-Emitting Diode Medical Program-Progress in Space Flight and Terrestrial Applications”. Space Tech. & App. Int'l. Forum. Space Tech. & App. Int'l. Forum: 37–43

 

  1. Huang YY,Mroz P, & Hamblin M, (2009): “ Basic Photomedicine” http://www.photobiology.info/Photomed.html

  2.  

    Karu T. (1999): “Primary and secondary mechanisms of action of visible to near-IR radiation on cells”. J Photochem Photobiol B, J Photochem Photobiol B: 1–17

     

  3. Parker S, “Laser :Tissue Interaction and Its Application in Clinical Dentistry” Int J Laser Dent (2011);1(1):1-8

 

  1. Carroll J, Milward MR et al “Developments in low level light therapy (LLLT) for dentistry” Dental Materials (2014); 30:465-475

 

  1. Tuner J, Hode L, “The Laser Therapy Handbook” Prima Books (2007). ISBN: 91-631-1345-7

 

  1. Benedicenti A, “Atlas of Laser Therapy” tw-Media (2005); 3rd edition. ISBN: 88-89626-02-X

 

  1. Huang YY, Sharma S et al “Biphasic dose response in low level light therapy - an update” Dose Response (2011); 9:602-611

 

  1. Kim WS, Calderhead RG. Is light-emitting diode phototherapy (LED-LLLT) really effective?

              Laser Ther. 2011;20(3):205-15. Review

 

 

  1. Pejcic A, Kojovic D et al “The Effects of Low Level Laser Irradiation on Gingival Inflammation” Photomed Laser Surg (2010); 28(1):69-74

 

  1. Pesevska S, Nakova M et al “Effect of laser on TNF-alpha expression in inflamed human gingival tissue” Lasers Med Sci (2012);27:377-381

 

  1. Ozcelik O, Hayatc MC et al “Improved wound healing by low level laser irradiation after gingivectomy operations: a controlled clinical pilot study” J Clin Periodontol (2008);35:250-254

 

  1. Chow R, Armati P et al “Inhibitory Effects of Laser Irradiation on Peripheral Mammalian Nerves and Relevance to Analgesic Effects: A Systematic Review” Photomed Laser Surg (2011);29(6):365-381

 

 

  1. Raja S, Byakod G et al “Growth factors in periodontal regeneration” Int J Dent Hygiene (2009); 7:82-89

 

  1. Aykol G, Baser U et al “The Effect of Low Level Laser Therapy as an Adjunct to Non Surgical Periodontal Treatment” J Periodontol (2011);82: 481-488

 

  1. Qadri T, Miranda L et al “The short term effects of low-level lasers as adjunct therapy in the treatment of periodontal inflammation” J Clin Periodont (2005);32: 714-719

 

  1. Lalla RV, Bowen J, et al “MASCC=ISOO Clinical Practice Guidelines for the Management of Mucositis Secondary to Cancer Therapy”

    Cancer 2014; DOI:10.1002/cncr.28592

     

    19. Kesler et al. J Oral Implantol (2011) 37:195-204

    Platelet Derived Growth Factor Secretion and Bone Healing After Er:YAG Laser Bone Irradiation”