Development of low reactive-level laser therapy and its present status

A new subspecialty in the medical application of the laser has developed, especially over the last decade, depending on the therapeutic rather than the surgical applications of the laser. Laser therapy, or preferably, Low reactive-Level Laser Therapy (LLLT) is now being recognized as a valid medical tool. Two types of LLLT are presented, simultaneous and pure. In surgical laser applications, ranges of heat are generated in the target tissue, destroying or altering its architecture. This is referred to as high reactive-level laser treatment, or HLLT. In addition, nonphotothermally destructive reactions may also occur, such as photo-osmosis. These are also part of HLLT. Simultaneously, nondestructive thermal and nonthermal bioactivation occur at the periphery of the target tissue: this is "simultaneous LLLT" and occurs along with HLLT, explaining some of the advantages of laser surgery. Laser systems have been developed which deliver power and energy densities below the destructive level, only to activate the irradiated tissue. This is "pure LLLT." The history and background of LLLT are presented, the terminology discussed, and practical applications of LLLT are presented.