Most therapeutic lasers are classified by the Food and Drug Administration as Class III lasers, which are known as low-level laser therapy (LLLT), cold laser therapy and low-power laser therapy because they are restricted to intensities that can only induce minimal (if any) temperature elevation (not more than 0.1-0.5° C).  This limits the amount of energy delivered and laser power to 500 mW or less.  While they do seem an effective way to produce analgesia and accelerate healing of a variety of clinical conditions, they are not as powerful or effective as higher powered lasers.

 

The FDA has cleared Class IV therapeutic lasers (not to be confused with Class IV surgical lasers, which cut and cauterize tissue.) which are differentiated from Class III Lasers based on much greater power, offer faster results, deeper penetration, and a larger surface treatment area.

 

Class IV lasers may offer better therapeutic outcome, based on six characteristics of this new technology:

1.       Class IV lasers can deliver up to 1,500 times more energy than Class III and consequently reduce treatment time because and thus dosages of therapeutic energy.

2.       Deeper penetration into the body. Leading Class III lasers only penetrate 0.5-2.0 cm. Class IV can penetrate up to 10 cm.

3.       Larger treatment surface area.  Class III cover a treatment area of 0.3-5.0 cm2 while Class IV cover up to 77 cm2.

4.       Greater power density.  Power density indicates the degree of concentration of the power output. This property has been shown to play a major role in therapeutic outcomes.

5.       Continuous power supply.  In Class III lasers, the power is pulsed or modulated approximately 50 percent of the time. In other words, light is permitted to pass through the probe for only 50 percent of the total operating time. In most cases, Class IV lasers deliver a consistent amount of energy over a given time. Their power can be adjusted for acute and chronic conditions.

6.       Superior fiber optic cables. Fiber optic cables transmit laser energy from the laser to the treatment probe (wand) at the end of the cable. Several studies reveal that as much as 50 percent of the light energy generated by a Class III laser may be lost by the time it reaches the end of the probe.

 

Class IV laser therapy has demonstrated the ability to significantly accelerate and enhance the body's natural defense and repair components in the presence of injury, inflammation and certain disease processes through the action of photo-stimulation of light reactive biological receptors (chromophores) in the body.  Laser therapy is consistent in providing pain relief, reducing injury damage and loss of function by modifying the effects and limiting the duration of inflammation, as well as enhancing specific repair and healing processes, and facilitating more rapid repair and producing stronger healed tissue structures. Multiple clinical studies have noted the following results of Laser therapy:

 

•        Increased collagen production

•        Enhanced nerve regeneration

•        Increased vasodilatation

•        Reduced inflammatory duration

•        Increased cell metabolism

•        Increased pain threshold

•        Increased cell membrane potential

•        Reduced edema magnitude

•        Increased microcirculation

•        Increased tissue and bone repair

•        Increased lymphatic response

 

Lasers work when light receptive chromophores are irradiated with coherent laser light.  The transferred energy stimulates increased action in cellular and sub-cellular tissues.  Penetrating much deeper than other incoherent light wave forms, laser light activates increased mitochondrial ATP synthesis, mitigates mast cell inflammation and increases Ca++ ion presence and beneficial reactive oxygen species (ROS) production.  Through the action of photo bio-stimulation, oxidative metabolism is increased via cytochrome C oxidase and photosensitization of hemoglobin.  Laser irradiation stimulates increased endorphin release and increased prostaglandin synthesis.  Photon-stimulation leads to both localized and systemic reactions that result in immunomodulation and reduction of inflammation.  Damaged skeletal, connective and neurological tissues and structures react with enhanced healing with lasers.