الفهرس 
STRUCTURE OF THE SKINOnly 14 pages are availabe for public view
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Abstract
Wrinkles, also known as rhytidees, may be defined as creases or furrows in the skin surface, reflecting the underlying alterations in the delicate architecture of the dermal connective tissue, namely the collagen and elastic fibres.
Human skin, like all other organs, undergoes chronological aging or intrinsic aging. In addition, unlike other organs, skin is in direct contact with the environment, and therefore undergoes aging as a consequence of environmental damage i.e. extrinsic aging. Intrinsic aging; also known as the natural aging process, is the slow irreversible degeneration of tissues, which affects almost all body organs. It usually begins in mid 20s and is a continuous process, which by definition is inevitable and not subject to manipulation through changes in human behavior. Extrinsic aging develops due to several factors; ionizing radiation, severe physical and psychological stress, alcohol intake, poor nutrition, environmental pollution, smoking and exposure to UV radiation. Among all these environmental factors, UV radiation contributes up to 80%.
Wrinkles can be classified according to etiology as orthostatic, dynamic and gravitational wrinkles; according to the depth as fine, medium and deep wrinkles and according to Glogau photoaging as class I, II, III and IV.
Anti-aging treatments occupy a wide spectrum ranging from basic moisturizers to major surgeries. Choosing the right ones at the right time is critical for successful outcome. Based upon the degree of aging changes, skin characteristics, desire of the patient, and the morbidity and cost the patient is willing to tolerate, the optimal regimen may be offered.
Topical therapeutic modalities imply photoprotection, use of retinoids and topical antioxidants such as vitamin C, bleaching agents and peels with alpha-, beta- and polyhydroxy acids. Resurfacing procedures includes microdermoabrasion, superficial chemical peeling, medium-depth peeling, ablative and non-ablative laser resurfacing, radiofrequency therapy and face lifting procedures.
Chemical peeling is one of the oldest rejuvenating methods used. Despite the appearance of alternatives, it is widely used because it is relatively inexpensive and its short and long-term effects are well understood. Mild peeling solutions only loosen and remove stratum corneum, while the stronger ones can affect the entire epidermis and even the upper dermis. Hence, chemical peels are classified as light (superficial), medium and deep. The deeper the peel, the greater is the potential for both cosmetic improvement and side effects.
Trichloroacetic acid 35-50% is the agent most commonly employed in the treatment of actinic keratosis, pigmentations, and photoaging. As a matter of fact, it is indicated for the fine cross-hatched facial rhytidees and moderate perioral wrinkles, but not for deeper rhytidees of lax skin or caused by muscles of facial expression. Habitually, medium-depth peelings have no complications, when the technique is well planned. Still, sometimes, as a consequence of the patient’s type of skin, an inexperienced practitioner, or other circumstances, unpredicted complications may occur such as: dyspigmentation, erythema, hypertrophic and keloid scars, infections, accentuation of telangiectasias and darkening of pigmented nevi.
Laser resurfacing with the C02 and erbium laser remains the best choice for removal of more severe sundamage and correction of elastosis and deeper wrinkling of the skin. Despite achievement of an appreciable clinical improvement, such ablative resurfacing modalities can result in significant oedema and erythema lasting for several weeks. Moreover, well-known morbidities, long-term sequelae, and potential complications have all been well documented. The typical prolonged recovery times and potential complications associated with these modalities may limit their use in patients who desire a rejuvenation procedure with reduced downtime and minimal risk
The basic concept behind the use of lasers in the treatment of wrinkles is the induced formation of new dermal collagen following a deliberate laser energy-induced thermal damage in the mid to upper dermis.
In contrast to ablative rejuvenation methods, non-ablative laser rejuvenation procedures attempt to achieve a dermal injury response without injuring the epidermis. Non-ablative lasers use laser energy to stimulate collagen synthesis in the dermis without damage to the epidermis. Non ablative procedures have the advantages of minimal downtime, because the epidermis is not removed or vaporized. The disadvantages are that they require multiple treatments, costing much, and the results are not immediate. The final result may not be seen until as much as one year has passed.
Non-ablative laser photorejuvenation includes: vascular, infrared, and pigmented lasers. Vascular lasers include the 585 to 595-nm PDL (yellow) light and the 532-nm (KTP) (green) light. Infrared lasers include the 1064-nm, QS (Nd:YAG) laser, the 1064-nm long pulsed Nd:YAG laser, the 1320-nm Nd:Y AG laser, the 1450-nm diode laser, and the 1540-nm Er:glass laser. Pigmented lasers include the QS Nd:YAG (532 and 1064 nm), QS ruby (694 nm), and QS alexandrite (755 nm) lasers.
The extended pulse 1064-nm Nd:YAG laser is a safe and proven technology that has been effectively used in laser epilation in patients of all skin types and colors. The advantages of this modality for wrinkle reduction include the technical ease of performing the procedure, minimal to no patient discomfort, and the ability to treat all skin types with little risk of epidermal injury.
The aim of this study was to compare TCA 35% chemical peeling with the non-ablative 1064nm Nd:YAG laser for treatment of facial wrinkles.