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SKIN REJUVENATION To improve your looks, to support or recover skin respectability and beauty is a natural wish for any individual of any sex and age. Youthful appearance, resistance to aging, satisfaction with one’s appearance not only improve self-confidence, but make people treat you accordingly as well. Methods of appearance correction may vary: nutritious masks, instrument stimulation of facial dermis and musculature. Yet, that is not so easy to remove existent wrinkles and skin creases. Main factors causing skin aging are diminishing functioning of conjunctive tissue (fibroblasts) and decreasing tightness and thickness of collagen fibers in the dermal papillary layer. Therefore, the most common skin rejuvenation techniques are based on stimulation of reparative processes in this layer. The above techniques include: 1) chemical peeling by fruit acids; A characteristic feature of all these methods is ablation of the upper dermis, what stimulates fibroblast growth, thickening of layers and improvement of collagen tightness. The first 2 methods have common drawbacks, such as low effect at shallow treatment and danger of papillary layer damage and scarring at deep treatment, since it is rather difficult to precise the treatment level and to perform visual control over the process. The drawbacks were somewhat reduced with the development of laser ablative skin rejuvenation techniques based on effective water absorption of the near-infrared spectrum. CO2 (10,6 mkm), Er:YAG (2,94 mkm) and Ho:YAG (2,1 mkm) lasers introduced to the clinical practice allowed precise dosing of vaporization depth and warming of deep dermal layers. Laser ablative skin resurfacing turned out a true revolutionary breakthrough in cosmetology due to the perfect treatment results. However, both traditional and laser ablative skin resurfacing techniques have evident common side effects upsetting patients, namely:
Due to the aforesaid reasons patients suffer a prolonged downtime and feel discomfort, some even find these methods unacceptable. Therefore, non-ablative methods of skin rejuvenation grew extremely topical, such as to improve skin look without ablation of the upper dermis and, thus, without side effects caused by the ablative resurfacing. The research and clinical experience prove that nowadays there are two most effective approaches to stimulate skin renovation preventing damage of the epidermis. The first method suggests the papillary dermal layer heating due to the effect of water absorption of certain laser wavelengths. Lasers emitting wavelengths within the low water absorption spectrum (1,2 – 2,0 mkm) are used for this goal. This spectrum range ensures sufficient laser light penetration into the skin while the epidermis remains undamaged. Lasers applied are a Nd:YAG (1,32 mkm), an Er-doped glass laser (1,54 mkm), and diode lasers (1,45 mkm) [1]. Significant improvement of skin texture and tone was obtained with the Nd: YAG laser at a 1,32 mkm wavelength, 3,2 msec pulse duration and 10-30 J/cm2 fluence [2]. Side effects included mild edema and erythema resolved within 2 days. No pigmentary changes were observed. As for the diode laser with the 1,45 mkm wavelength, it was successfully applied not only for overall skin improvement but also in treatment of papular and pustulous acne [2]. Nevertheless, all the aforesaid treatment methods require skin cooling and anesthesia. The second method of non-ablative skin remodeling is based on light absorption by hemoglobin with partial coagulation of papillary dermal microvasculature and release of inflammatory mediators. The result is microvasculature renewing, fibroblasts stimulation, new collagen production. The technique applies lasers and pulsed light sources emitting radiation in the hemoglobin absorption spectrum. These are dye lasers (585 – 600 nm), lamp light sources with cut-off filter (645 – 1100 nm), a Nd: YAG laser (1064 nm) and the 2nd harmonic of the Nd: YAG laser (532 nm).
Authors [1,3,4] carried out a comparative research on quite a large group of patients, and the research showed that treatment with 500 nm up to 900-1000 nm wavelengths induces problems well known out of laser and photo hair removal analysis. These problems include: 1) unwanted melanin absorption in the epidermis barriers light penetration into the skin and does not allow to “heat” dermal layers, especially in treatment of dark-skinned or sunburnt patients; 2) epidermis heating can result in adverse effects such as prolonged erythema and burn blistering which, as it is claimed by authors [5], are especially profound when applying lamp light sources. To the contrary, the Nd: YAG laser emission (1064 nm wavelength) is negligibly absorbed by melanin and water (see figure), thus making microvascular hemoglobin the main target for fibroblast activation. Pulse energy and duration may be varied in a wide range providing a possibility to find the “mildest” mode for microvasculature treatment. In order to find such a mode effectiveness of skin remodeling using the Nd: YAG laser with various parameter combinations was investigated. Results show that short pulses (6-20 nsec) can destruct microvasculature instead of its coagulation, such destruction often accompanied by prolonged erythema [6]. “Long” pulses (5-50 msec) usually applied in laser hair removal and in treatment of vascular lesions are also no good for photo-rejuvenation since they significantly exceed time needed for microvascular thermal relaxation. The optimum combination in respect of skin rejuvenation with the Nd: YAG laser is pulse duration of about 300 mksec and 15-30 J/cm2 fluence [4]. Notwithstanding rather a low fluence, the mentioned parameters provide short-time impact with intensity much greater than used for hair removal. Heat is generated in the papillary layer and spreads to the surrounding tissue. Epidermal temperature increases to 43-48°C, the treatment process therefore does not require anesthesia and cooling, nor any special subsequent care. Side effects are limited to transient erythema and feeling of warmth in a treated area. The treatment procedure includes 2-4 follow-up visits at a spacing of 2-4 weeks. Wrinkles continue vanishing within 6-12 months after the treatment course. A most likely reason for such long-time skin regeneration is supposed to be that dermal remodeling process is “turned on” at the cellular level and continues to run without any additional stimulation [7]. The most remarkable result of the Nd: YAG treatment with the above parameters, except for enhanced skin smoothness and smaller pore size, is a significant improvement in skin color and texture. The effect is resultant from simultaneous selective treatment by the 1064 nm laser light of small vascular components that cause diffuse erythema. The DeLight multi-application laser system perfectly suited for laser hair removal and vein treatment has been specifically optimized by SOLAR LS for non-ablative skin therapy. The optimal concordance between the DeLight pulse duration and microvascular thermal relaxation time together with a wide range of energy parameters ensures a possibility of adjusting a treatment mode for different skin type patients to effectively smoothen skin due to new collagen production and tightening of collagen fibers, and to improve skin tone granting from accompanying selective coagulation of microvasculature. Unfortunately, at the present time, laser non-ablative dermal
remodeling is not as effective in wrinkle reduction as ablative
techniques are. Yet, skin rejuvenation with the Delight Nd: YAG
laser is an efficient sparing method ideally suited for working
patients of middle age desiring to improve their look without any
downtime, with no regard to sunburn or phototype. Application of
the Delight laser system effectively reduces porosity and tuberosity
of skin, smoothes fine and medium wrinkles, and successfully improves
overall skin toning. References: 1. David J. Goldberg. Non-Ablative Dermal Remodeling: A Review.
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