Low Level Laser Therapy is a safe and effective procedure thats improves wound healing process, tissue regeneration, inflammatory reduction, and analgesia, and is used to treat a variety of oral diseases and worked in the red or near-infrared spectrum of light (400–980 nm) with a power range of 1–500 mW and frequency of 1–500 mW.

Definition and history of Low Level Laser Therapy

In a number of pharmaceutical applications, the use of monochromatic light to interact with specific tissue chromophores to create positive benefits such as analgesics, an anti-inflammatory reaction, biostimulation, and antimicrobial activities has been found to be useful. Light’s uplifting and healing properties have been recognized since the beginning of humanity.

Ancient humans have attributed the sunlight and its power to deities, such as Ra, the Egyptian deity of the sun. They were aware that some flowers may be utilized to treat skin conditions such as vitiligo and psoriasis. Egyptians and others from other civilizations utilized this as an early type of photodynamic treatment.

Some individuals discovered that sunlight was effective for destroying germs around the late 19th century. Tuberculosis, a disease that was difficult to cure and had a huge societal impact, was commonly treated using pre-antibiotic heliotherapy (sunlight exposure).

The surgical uses of lasers in medicine began to be researched after Theodore Maiman developed the first laser in 1960). A Hungarian physician Andre Mester investigated the Ruby laser, so according to his results, skin cancer decreased after being treated with an ineffective device that produced insufficient energy to perform surgery.

Cancer cells were implanted into laboratory rats with surgically removed facial hair, and the region where the cells were implanted was treated with a low-cost ruby laser. Interestingly, the irradiated rats experienced better surgical wound healing and hair regrowth than the non-irradiated rats.

Mester used the term “biostimulation” to describe this phenomenon, and he continued his study to prove that there is a relationship between dose and effect, demonstrating that an excessive quantity of energy causes bioinhibition rather than stimulation.

Mechanism of Low Level Laser Therapy

Photobiological law states that “in order for low-power visible light to have an influence on a live biological process, photons should be taken by electronic absorption bands of certain molecular photoreceptors, or chromophores (molecules that appear either as conjugated pi-electron systems or as metal complexes, and which determine the hue of the chemical in which they are present.).

Absorption of monochromatic red and near-infrared light by parts of the electron transport system has been related to the cellular process of Low Level Laser Therapy. Research has confirmed that mitochondria is essential for the biological reaction to red and near-infrared radiation. The benefits of lighting on isolated rat liver mitochondria included improving proton electrochemical potential, raised ATP, NADH, RNA, and protein production as well as the membrane potential and O2 demands rise.

The findings of different research confirm the hypothesis that the cellular principle of Low Level Laser Therapy treatment is dependent on a rise in mitochondrial oxygen metabolism, which is produced by the stimulation of electronic parts of the respiratory chain. The cellular manifestations of Low Level Laser Therapy were been divided into three categories: primary, secondary, and tertiary.

Primary responses are those caused by photon absorption, but secondary effects are not specific to Low Level Laser Therapy, since their happening is dependent on cell responses. Tertiary effects are the lowest predictable since they are influenced by both the internal and external environment as well as intracellular interactions, which describe why treating one lesion may also promote healing in adjacent lesions.

General Effects of Low Level Laser Therapy

Anti-inflammatory Effect

Since Low Level Laser Therapy has no side effects, it’s has been the subject of extensive research into how it reduces inflammation by comparing the effects of various wavelengths and other factors on injured tissues. Cytokines are activated by laser light with a wavelength range from 650 to 980 nm, on oxidative stress lowering ROS levels and activating macrophages, whose number is enhanced in inflammatory simulation models.

Numerous studies in vitro and animal models, as well as a few human researchs, demonstrate an accelerated inflammatory response, with activation of both pro-and anti-inflammatory cytokines and mature collagen synthesis just 7 days after injury. In addition, it was discovered that Low Level Laser Therapy’s anti-inflammatory effects are on par with those of dexamethasone. A favorable result was obtained with fluences in the range of 1 to 7.5 J/cm2, with an increase in the activation levels of the phlogosis mediators, but higher fluences were not obtained with the same effect.

Analgesic Effect

Even though the intrinsic processes of Low Level Laser Therapy have yet to be completely understood, it has been investigated for their effects on painful stimuli. In a comprehensive examination of the literature, Bjordal found a number of laboratory experiments looking for molecular processes behind the management of pain.

An increase in the production of endogenous opioids, a reduction in the conduction of nerve impulses of the peripheral nerve, reduction in the levels of oxidative stress and edema, an anti-inflammatory impact on the local level, along with the generation of biochemical indicators, increased microcirculation associated with the creation of new vessels in the region of injury and discovered that the enzyme COX-2 was down-regulated, which may have a short-term effect on the pain associated with the acute inflammatory response.

Biostimulating Effects

With its anti-inflammatory and analgesic properties, as well as its biostimulatory properties, a low-level laser therapy (Low Level Laser Therapy) plays a major role in this regard. Wound healing is one of the most researched disorders that may benefit from Low Level Laser Therapy. Low Level Laser Therapy is supposed to assist in the healing of wounds by reducing pain, inflammation, and speeding up the formation of new tissue. Some of wavelengths included in the optical window have been studied individually or together, with many of the wavelengths examined. These studies have ranged from red to near-infrared (mainly 810 and 980 nm).

Bactericidal Activity

According to the World Health Organization, an increasing number of bacteria are developing resistance to current antibiotic classes as a result of the indiscriminate and often unnecessary use of antibiotics. As the increasing need for antibacterial treatments like Low Level Laser Therapy, it’s possible that this technique will become one of them. Scientists have looked at how the use of noncoherent blue light (400–500 nm) and peroxide may be utilized to identify bacteria that have had their membranes damaged by OH radicals.

Oxygen radicals with a great deal of reactivity. Because of the effects of Low Level Laser Therapy on cell proliferation and the enhancement of chemotactic activity on phagocytosis by neutrophils and macrophages, bacterial proliferation may be controlled by the immune system stimulation mechanism.

The effects of Low Level Laser Therapy on cells and wound healing

Immune cells

The proliferative response of peripheral blood lymphocytes is enhanced by low-level laser therapy (Low Level Laser Therapy). Low Level Laser Therapy stimulates the phagocytic activity of macrophages during the early stages of the healing response to a wound. It has the potential to alter immunological cells that generate cytokines and growth factors. The local immune system, blood and lymph circulation, and cell metabolism are all affected by laser therapy. It has an impact on pain because it releases prostaglandins and endorphins.

Epithelial cells

The use of low-level laser therapy has been found to promote the migration of human epidermal keratinocytes, leading to a faster wound closure.


Low Level Laser Therapy may induce myofibroblast proliferation and differentiation, which results in increased compressive properties of tissue, which is necessary for effective healing process.

Cells of the nervous System

Low Level Laser Therapy has the potential to decrease the inflammatory processes while also restoring activity to damaged nerves.

The circulatory system (blood vessels)

The use of low-level laser therapy may help to decrease pressure in vascular smooth muscle, which may help to alleviate pain. The most important receiver of radiation is the blood.

Wound healing

The use of low-level laser therapy may enhancement in scar tissue formation and may be attributed to enhanced vasodilation and relief the stress of smooth muscles, improvement scar tissue formation, earlier tissue regeneration and greater proliferation of fibroblasts

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