Rapid healing of gingival incisions by the helium-neon diode laser.

Fifty-eight extraction patients had one of two gingival flap incisions lased with a 1.4 mw helium-neon (670 nm) diode laser for 30 seconds (fluence = 0.34 J/cm2). Healing rates were evaluated clinically and photographically. Sixty-nine percent of the irradiated incisions healed faster than the control incisions. No significant difference in healing was noted when patients were compared by age, gender, race, and anatomic location of the incision. This study concludes that helium-neon diode lasers, at the previously mentioned energy level, increase the rate of gingival wound healing in 69 percent of patients, without any side effects. For the last 30 years, low-power lasers in dentistry have appeared to stimulate healing rates and increase the rate of repair of injured tissue. Helium-neon and similar lasers emit light in the red (600-700 nm) spectrums and produce energy densities (fluences) below 20 Joules/cm2. They have been studied in a variety of animal tissue culture and human evaluations to determine their ability to increase the rates of wound healing by biostimulation. Over the last three decades, researchers have found that ruby and gas helium-neon (low-power laser radiation) have a biostimulatory effect on living tissue. Studies show that under specific conditions, red spectrum laser light speeds the healing of wounds. Photons from the red light lasers, which include ruby lasers (694 nm), helium-neon gas lasers (632 nm), and helium-neon diode lasers (650-670 nm), appear to stimulate rapid epithelialization and fibroblast (collagen) proliferation in animal and human tissue cultures. Low-power lasers have been reported to reduce post-extraction pain and swelling and to increase rates of wound healing (including scar formation, phagocytosis) in cell culture, animal, and human clinical studies. The new, compact, and inexpensive (under $50) helium-neon diode lasers have produced similar effects. These FDA Class IIIa lasers have no hazards associated with them, although one should avoid direct exposure to the eye for a prolonged period of time. In the past, many biostimulation studies using red spectrum lasers produced confusing data and conflicting results. Some studies reported that the biostimulation effect did not occur in all cases of laser irradiation, while other research reported that it did. Results seem to depend on the delivery of appropriate energy fluence levels (between 1 and 20 J/cm2) and the type of laser (wavelength) used. Several of these studies never described the levels of laser energy used to promote the described biostimulatory results. This caused controversy when determining whether or not helium-neon lasers influence wound healing. Studies suggest that low-power laser exposure can significantly increase the healing rate during the first few days of the healing process; however, studies do not show appreciable net benefit as compared to controls toward the end of a two-week wound repair cycle. The increased healing effect appears to be centered around the early, most sensitive stages of the healing process. Several studies showed optimum tissue healing rates at helium-neon laser exposure levels between 1 J/cm2 and 20 J/cm2. Laser-enhanced biostimulation has been reported to produce metabolic changes within the cells. This results in faster cell division, rapid matrix production (increased collagen, myofibroblasts, etc.), and cell movement. There have been few controlled studies using adequate numbers of human subjects in identifying the beneficial effects of helium-neon laser biostimulation. Ethical concerns, bulky equipment, and problems with biased study designs have frustrated a practical evaluation of laser biostimulation for general dental practice. A recently published "preliminary" study involving 52 patients was designed to reduce these issues. The purpose of this study is to complement the above research and to evaluate whether helium-neon diode laser radiation at average fluences of 0.34 J/c