Laser hair removal is the process of removing hair by exposing pulses of laser light that destroy hair follicles. It has been done experimentally for about twenty years before it became commercially available in the mid-1990s. One of the first published articles describing laser hair removal was written by a group at Massachusetts General Hospital in 1998. Laser hair removal is widely practiced in clinics, and even in homes using devices designed and valued for consumer self-care. Many reviews about laser hair removal methods, safety, and efficacy have been published in the dermatology literature.
R. Rox Anderson found that it is possible to selectively target specific chromophores with lasers to partially damage the basal stem cells within the hair follicles. This method proved successful, and was first applied in 1996. In 1997, the US Food and Drug Administration approved this hair removal tactic. As this technology continues to be researched, laser hair removal becomes more effective and efficient; thus, now a common method of removing hair for long periods of time.
Video Laser hair removal
How it works
The main principles behind laser hair removal are selective photothermolysis (SPTL), light wavelength matching and specific pulse duration to obtain optimal effect on targeted tissue with minimal effect on adjacent tissue. Lasers can cause local damage by selectively heating the dark target material, melanin, thus heating the basal stem cells in the follicles that cause hair growth, the follicles, while not heating the rest of the skin. Light is absorbed by dark objects but is reflected by light and water objects, so that laser energy can be absorbed by dark matter in hair or skin, with more speed and intensity than just skin without dark adult hair or melanin.
Melanin is considered the main chromophore for all laser hair removal currently on the market. Melanin occurs naturally in the skin and gives skin and hair color. There are two types of melanin in the hair. Eumelanin gives brown or black hair color, while pheomelanin gives blond or red hair. Due to the selective absorption of photon laser light, only hair with a color like black, brown, or reddish brown hair or a dirty blond can be removed. White hair, blond light, and strawberry blonde hair do not respond well. The laser works best with dark rough hair. Bright skin and dark hair are the ideal combination, most effective and produce the best results, but laser-like lasers Nd: YAG is able to target black hair in patients with dark skin with some success.
Laser hair removal has been in use since 1997 and has been approved for "permanent hair reduction" in the United States by the Food and Drug Administration (FDA). Under the FDA definition, permanent hair reduction is a stable long-term decrease in the number of hairs regenerating after the treatment regime. Indeed, many patients experience complete hair growth in the treated area in the years following their last treatment. This means that although laser treatment with these devices will permanently reduce the total body hair count, they will not result in the permanent removal of all hairs.
Laser hair removal has become popular because of its speed and efficacy, although some success depends on the skills and experience of laser operators, and the choice and availability of different laser technologies used for this procedure. Some will require touch treatment, especially on large areas, after the initial set of 3-8 treatments.
Maps Laser hair removal
Comparison with other removal techniques
Comparison with intense pulsed light
A 2006 review article in the journal "Lasers in Medical Science" compares intense pulsed light epilator (IPL) and both alexandrite and diode lasers. The review found no statistical differences in short-term effectiveness, but a higher incidence of adverse events with laser-based diode treatments. Hair reduction after 6 months was reported as 68.75% for alexandrite lasers, 71.71% for laser diodes, and 66.96% for IPL. Adverse reactions were reported as 9.5% for alexandrite lasers, 28.9% for laser diodes, and 15.3% for IPL. All side effects are found temporarily and even pigmentation changes return to normal within 6 months.
IPL, although technically it does not contain lasers, is sometimes mistakenly referred to as "laser hair removal". IPL-based methods, sometimes called "phototricholysis", or "photoepilation", use xenon flash lights that emit full-spectrum light. IPL systems typically produce wavelengths between 400 nm and 1200 nm. Filters are applied to block shorter wavelengths, so only use longer "red" wavelengths for clinical applications. IPL offers certain advantages over lasers, especially in pulse duration. While lasers can generate short pulse trains to simulate longer pulses, the IPL system can produce up to 250ms pulse widths useful for larger diameter targets. Some current IPL systems have proven to be more successful in removing hair and blood vessels than many lasers.
Comparison with electrolysis
Electrolysis is another method of hair removal that has been used for over 135 years. As newer laser technologies are used correctly and with some treatments, electrolysis can be used to remove 100% of the hair from an area and is effective on hair of all colors, if used at adequate power level with proper technique. But the treatment is very slow and boring compared to newer laser hair removal. More hair can grow in certain areas susceptible to hormone-induced growth (eg female chin and neck) based on individual hormone levels or changes in it, and a person's genetic predisposition to grow new hair.
A study conducted in 2000 at the ASVAK Laser Center in Ankara, Turkey compared alexandrite and electrolysis lasers to hair removal in 12 patients concluded that laser hair removal was 60 times faster, less painful and more reliable than electrolysis. It is important to note that the type of electrolysis carried out in this study was galvanized electrolysis, rather than thermolysis or a mixture of both. Galvanic currently takes 30 seconds to more than a minute to release any hair while thermolysis or mixture may require less. This study did not test the capabilities of all modern electrolysis forms.
Comparison with shaving
Shaving is a technique in which a person removes hair from the skin with a razor. A razor is needed to shave and is a way to get rid of hair in no time.
Shaving has been popular as a hair removal technique while at least since the 1700s. In 1895, King Gillette invented a sharp, thin, disposable razor, and was cheap enough to make. This razor is very popular and has now been modified to look like it is today.
Shaving, however, is not as permanent as laser hair removal and can cause irritation to the shaving area.
Comparison with waxing
Waxing is another option for hair removal. This method is an efficient way to remove hair during a semi permanent period. The ancient Egyptians developed the same mechanism, sugar, in which people would mix oil and honey and then apply it to the skin.
When waxing has evolved, there are two types of waxing. In one, the strip is ready for use, and one can apply it to the skin and peel it in the opposite direction to hair growth. Another involves heating up the candle, applying it to the skin, and then placing the cloth on it and pulling away from hair growth.
Rule
In some countries, including the US, hair removal is an unregulated procedure that anyone can do. In some places, only doctors and personnel are supervised by a doctor who can do so, while in other cases permission is granted to licensed professionals, such as ordinary nurses, physician assistants, beauticians and/or beauticians.
In Florida, the use of lasers, devices such as lasers and powerful pulsed light devices are considered medicines, and require them to be used only by doctors (DO or MD), physician assistants under medical supervision, or advanced enrolled. nurse practitioners under a protocol signed by a doctor. An electrology expert working under direct supervision and a doctor's responsibility is also allowed to do laser hair removal in the state of Florida.
Type
Some wavelengths of laser energy have been used to remove hair, from visible light to near-infrared radiation. These lasers are characterized by their wavelength, measured in nanometers (nm):
Pulse width (or duration) is one of the most important considerations. The length of the heating pulse is directly related to the damage achieved in the follicle. When trying to destroy the hair follicles the main target is the germ cells that live on the surface of the hair shaft. Light energy is absorbed by melanin inside the hair and heat is generated. The heat then goes out to the germ cells. As long as sufficient temperatures are maintained for the time taken then these cells will be successfully destroyed. This is very important - reaching the required temperature is not enough unless it is stored at that temperature for an appropriate time. This is determined by the Arrhenius Level Equation. To achieve this condition the laser/IPL system must be able to produce the required power output. The main reason why hair removal fails is because the equipment can not produce the desired temperature for the right time.
The spot size, or width of the laser beam, directly affects the depth of light energy penetration due to the scattering effects in the dermal layer. Larger beam diameters or devices that have linear scanning result in deeper deposition of energy and hence can lead to higher temperatures in deeper follicles. The hair removal laser has a spot size of the fingertip (3-18mm).
Fluence or energy density is another important consideration. Fluence is measured in joules per square centimeter (J/cmÃ,²). It is important to be treated at a setting high enough to heat the follicles enough to disable them from producing hair.
Epidermal cooling has been determined to allow for higher fluens and reduce pain and side effects, especially on darker skin. Three types of cooling have been developed:
- Cooling of contact: through a window cooled by water circulation or other internal coolant. This type of cooling is by far the most efficient method to keep the epidermis unprotected because it provides constant heat sinks on the surface of the skin. The sapphire window is much more conductive than quartz.
- Cryogenic spray: sprayed directly onto the skin just before and/or after the laser pulse
- Air cooling: forced cold air at -34 ° C
In essence, an important output parameter when treating hair (and other skin conditions) is the power density - this is a combination of energy, spot diameter and pulse duration. These three parameters determine what actually happens when the light energy is absorbed by the chromophore tissues be it melanin, hemoglobin or water, with the amount of damaged tissue determined by a combination of temperature/time.
Number of sessions
Hair grows in several phases (anagen, telogen, catagen) and the laser can only affect the hair follicles that are growing at the moment (early anagen). Therefore, some sessions are needed to damage the hair in all growth phases and force it to return to the small, colorless hair.
Some treatments depending on the type of hair and skin tone have been shown to reduce long-term hair. Most patients require at least seven treatments. The current parameters differ from device to device but manufacturers and doctors generally recommend waiting from three to eight weeks between sessions, depending on the area being handled. The number of sessions depends on various parameters, including body areas treated, skin color, hair roughness, reasons for hirsutism, and sex. Coarse black hair on light skin is the easiest to treat. Certain areas (especially male faces) may require more care to achieve the desired results.
The laser does not work well on brightly colored hair, red hair, gray hair, white hair, and fine hair with any color, like vellus. For dark-skinned patients with black hair, long Nd: YAG lasers with cooling tips can be safe and effective when used by experienced practitioners.
Usually the shedding of treated hair takes about two to three weeks. These hairs should be left to fall on their own and should not be manipulated by the patient for some reason, especially to avoid infection. Pulling hair after a session can be more painful and negate the effects of treatment.
Side effects and risks
Some of the normal side effects can occur after laser hair removal treatment, including itching, pink skin, redness, and swelling around the follicular treatment area or swelling (follicular edema). These side effects rarely last more than two or three days. The two most common side effects are acne and skin discoloration.
Several levels of pain should also be expected during the treatment. Numb cream is available in most clinics, sometimes at an additional cost. Some numbing creams are available at the counter. The use of a strong numbing cream on large areas of skin treated at one time should be avoided, as this has been very detrimental, and even killing, the patient. Usually, the cream should be applied about 30 minutes before the procedure. Icing area after treatment helps ease side effects faster. Ibrahimi and Kilmer reported the study of a new device handpiece diode with large-sized vacuum-assisted vacuum sizes to reduce pain levels associated with laser treatments.
Undesirable side effects such as hypo- or hyper-pigmentation or, in extreme cases, skin burning calls for adjustment in laser selection or settings. Risks include the possibility of burning the skin or discoloration, hypopigmentation (white spots), acne flares, swelling around the hair follicles (considered normal reactions), the formation of scabs, purpura, and infections. These risks can be reduced by appropriate laser treatment used in settings appropriate for individual skin types and care areas.
Some patients may exhibit side effects of either gel hair removal allergies used with certain laser types or numbing creams, or simply shave areas too early in relation to the treatment.
See also
- Depilatory
- Electrology
- Hair removal
- Shave
References
External links
- Laser Facts (US Food and Drug Administration)
- Additional Information on Removing Hair Safely
- American Dermatology Academy, Center for Public Resources, Hair Removal
- American Society for Dermatologic Surgery: "Laser Hair Removal Fact Sheet"
- National Laser Institute: "Laser Hair Removal Fact Sheet"
Source of the article : Wikipedia
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