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Authors : Dr. Sohini Banerjee, Dr. Sreya Pal, Dr. T. K.Pal.


Low level laser therapy has opened up a new era of treatment modality which includes the application of light energy to the cells in a lower power mode to promote bio-stimulative effect within the tissues.

It is widely used to accelerate wound healing, enhance remodelling of bone, restoration of normal neural function and reduction of pain following injury, and also for the modulation of immune system. This article would highlight the potential applicability of low level laser therapy in the wide field of dentistry and its limitations.


The introductions of “LASER”[Light amplification by stimulated emission of radiation] have made revolutions in the field of medicine and dentistry.1,2 Low level laser therapy(LLLT) is the latest addition to it which includes the application of laser light energy to the tissues in a lower power mode to generate bio-stimulative effects within the tissues without excessively causing the temperature rise.1,2,3,4

Semiconductor diode lasers(Gallium-aluminium-arsenide) or helium-neon which are often known as cold lasers are applied in output ranges of 50-500 mW with red or infrared wavelengths of electromagnetic spectrum(630-980 nm) to the tissues in a pulsed or continuous wave emission with defocused and/or non-contact mode to generate bio-stimulative effects.3,4,5,6

It usually promotes wound healing, enhances remodelling and repair of bone, restores normal neural function following injury and also helps in modulation of immune systems and nociceptive signals.2,3

Mechanism of action:

It acts according to Arndt-Schulz principle which states that if stimulus is too weak, no effect is seen but increased stimulation and optimal dose leads to optimal effect but further increase in dose leads to decrease effect. 4,5,6

Therefore, the bio-stimulatory effect of low level laser therapy would be produced by optimal dose exposure to the tissues in a non-contact/defocused mode. As, low level laser therapy deposits sub-themral energy within the tissues which then acts on the sub-cellular components i.e. on the antenna pigments of the electron transport chain within the membranes of mitochondria4,5,6 facilitating a wide arena of bio-stimulative properties which are shown in Fig.1,Fig.2.

The applications of low level laser therapy also thought to stimulate various cells such as lymphocytes, mast cells producing anti-inflammatory actions and also micro-capillaries causing change in capillary hydrostatic pressure resulting in oedema absorption, and elimination of intermediary metabolites.6,9,10

It would also thought to increase collagen production, mitotic activity of epithelial cells and fibroblasts, and produce analgesic effect by inhibiting nociceptive signals.6,9

If properly applied it has a wide range of potential applications in the field of dentistry.
Fig :1

Applications of low level laser therapy:

Low level laser therapy has a wide range of applications in dentistry (Fig.3).Some of the uses are listed as follows:
  1. Management of oral ulcerative lesions: It improves healing parameters and reduces the incidences of local recurrences, so it could be used as an effective alternative treatment modality for the management of recurrent apthous and herpetic lesions.11,12,13,14 It is also reported to decrease pain, xerostomia and also eliminates the lesions of mucositis in cancer patients receiving chemotherapy by its bio-stimulative effects.15,16,17

  2. Management of periodontal lesions: It might act as a potent additional therapy to nonsurgical periodontal treatments as it reduces gingival inflammation and hastens periodontal healing.18,19 It basically reduces the gingival inflammation and MMP-8 expression when applied after scaling and root planing and also thought to inhibit prostaglandin production(PGE2),thus modulating periodontal inflammatory processs.18 It would also accelerate wound healing following periodontal surgical procedures like gingivectomy, gingivoplasty.19,20,21 It also stimulates the production of basic fibroblast growth factor (bFGF) and also promotes transformation of fibroblasts into myofibroblasts thus facilitating wound contraction.19,20 The photodynamic therapy along with low level laser therapy might be a beneficial adjunct to non-surgical treatment of chronic peridontitis.6,20

  3. Management of post –operative pain: It might be used as an alternative method of post-operative pain control.4,5,6 As, it thought to promote stabilization of nerve membrane and affect the endorphins release, therefore inhibits the nociceptive signals and controls the pain mediator.10 It may also be used to reduce acute inflammatory pain in clinical setting as it could modulate the inflammation in a dose dependent manner.6

  4. Management of temporo- mandibular joint disorders and paresthesia: Several studies suggested that it would be effective in myofascial pain dysfunctional syndrome and arthralgias of temporo-mandibular joint.22 It also showed improved results in managing neurosensory disturbances after surgical procedure.4,5,6,10

  5. Management of dentinal hypersensitivity: It would thought to decrease dentin hypersensitivity by decreasing the adhesion of dentinal tubules, dissolution or dentin re-crystallization, evaporation of dentinal fluid, and or analgesic effect.5,24 Several studies suggest that application of LLLT can significantly decrease pain during cavity preparation if applied before therapy.5,6

  6. Dental implant: It would thought to enhance osseo-integration, and reduce post-operative pain and oedema following implant placement. So, it may be used asan additional treatment for accelerating healing around dental implant.23

Low level laser therapy acts by depositing subthermal energy within the tissues.4,5 Basically, therapeutic semiconductor solid active medium diode lasers (Galium-aluminium-arsenide)or helium-neon(He-Ne) lasers of visible red to infrared region of electromagnetic spectrum(630-980nm) are applied with output powers of 50-500mW to produce bio-stimulation and bio-modulation effect.5,9

Although, this low level laser therapy promote cell vitalization by increasing adenosine tri-phosphate production (ATP) within the mitochondrial respiratory chain, more studies would be required regarding standardization of treatment protocol, wave length of the laser used, and the therapy duration to make it effective in day to day clinical practice.


The bio-stimulative and bio-modulative properties of low level laser therapy can produce a wide variety of effects such as cellular proliferation and differentiation, acceleration of wound healing, angiogenesis and anti-inflammatory and pain modulating effect.4,5

It also have wide arena applications in the field of dentistry starting from the management of the oral and periodontal lesions to the treatment of dentinal hypersensitivity even to improve healing around dental implants. So, if properly applied it would become a boon to dentistry by having a wide range of applications with a single therapy.


  1. Maiman TH. Stimulated optical radiation in ruby.Nature 1960;187:493-494. (Cited in: Charles M Cobb. Lasers in Periodontics : A Review of the Literature .J Periodontol 2006; 77:545-564.
  2. Goldman L, Hornby P, Meyer R, Goldman B. Impact of the laser on dental caries. Nature 1964; 203:417.
  3. Suresh S, Merugu S, Mithradas N, Sivasankari. Low level laser therapy: A biostimulative therapy in Periodntics.SRM J Res Dent Sci 2015; 6:53-56.
  4. Walsh LJ. Dental lasers: some basic principles. Postgrad Dent 1994;4:26-29.
  5. Surendranath P, Arjunkumar R. Low level laser therapy-A review.IOSR Journal of Dental and Medical Sciences(IOSR-JDMS).2013;12(5):56-59.
  6. Boras et al. Applications of low level laser therapy. A text book of advanced oral and maxillofacial surgery.InTech.2013;327-339.
  7. Ohshiro T, Fujino T. Laser applications in plastic and reconstructive surgery. Keio J Med 1993;42:191-195.
  8. Nanami T, Shiba H, Ikeuchi S, Nagai T, Asanami S, Shibata T. Clinical applications and basic studies of laser in dentistry and oral surgery. Keio J Med 1993;42:199-201.
  9. Tuner J, Christensen PH. Low level lasers in dentistry. Available at: http://www.laser.nu/lllt/Laser_therapy_20%in_dentistry.htm.2002,pp263-283.
  10. Tezel A, Kara C,Balkya V, Orbak R. A evaluation of different treatment for recurrent apthous stomatitis and patient perception: Nd: YAG versus medication. Photomed Laser Surg,2009;27:101-6.

More references are availabe on request.