Photobiomodulation (the laser–tissue interaction) creates many consequences in the body's cells, with the most significant being reduction of pain and enhancement of healing. For example, therapeutic laser reduces pain by decreasing inflammation, as well as by decreasing tissue chemicals that stimulate pain and by affecting nerve conduction. Therapeutic
laser also enhances healing by increasing microcirculation (blood flow through the smaller blood vessels of the body), stimulating cellular activity, and increasing growth factors.
Therapeutic laser reduces pain and enhances healing.
Therapeutic lasers are not all the same. The two classes of therapeutic
laser in common use are class III and class IV. Class III therapeutic lasers are lower powered and typically use shorter wavelengths. Class IV therapeutic lasers are higher powered and use longer wavelengths. Different powered lasers will take different amounts of time to deliver the treatment dose of light energy. A higher-power laser translates to a shorter treatment time overall.
The therapeutic laser dose is expressed in joules of energy delivered at the skin surface. The dose is calculated by taking into consideration the type of laser equipment being used, the surface area of the affected body part, and the size of the patient. The dosage to treat deep tissues largely depends on patient size; for example, the bigger and bulkier the patient, the higher the concentration of energy needed. The laser dosage for treating superficial conditions is more consistent for many patients, regardless of size.
Once the dose of laser energy at the surface is determined, the surface area over the tissue to be treated is measured. With class III therapeutic lasers, the laser handpiece is typically moved around the area to be treated in a grid pattern; the handpiece remains in each spot until a certain number of joules of energy are delivered. The higher-power density of a class IV therapeutic laser means that the handpiece should remain in fairly constant motion, “painting” the surface of the treatment area in a systematic pattern.