In vivo experimental evaluation of skin remodeling by using an Er : Glass laser with contact cooling

Background and Objective: Selective dermal remodeling consists of inducing collagen tightening, neocollagen synthesis, or both, without damage to the overlying epidermis. This experimental study aimed to evaluate an Er:Glass laser emitting at 1.54 mu m combined with contact cooling to target the upp er dermis while protecting the epidermis. Study Design/Materials and Methods: Male hairless rats were used for the st udy. Different fluences (26-30 J/cm(2)) by using single 3-ms pulse irradiat ion or pulse train irradiation (1.1 J, 3 Hz) and different cooling temperat ures (+5 degrees C, 0 degrees C, -5 degrees C) were screened with clinical examination and histologic evaluation at 1, 3, and 7 days after laser irrad iation. Results: The clinical effects were clearly dose and temperature cooling dep endent. It seemed that single pulse irradiation led to epidermal whitening in most cases, whatever the cooling temperature. Conversely, pulse train ir radiation showed reproducible epidermal preservation and confinement of the thermal damage into the dermis. New collagen synthesis was confirmed by a marked fibroblastic proliferation, detected in the lower dermis at day 3 an d clearly seen in the upper dermis at day 7. Conclusion: This new laser seems to be a promising new tool for the treatme nt of skin laxity, solar elastosis, facial rhytides, and mild reduction of wrinkles. (C) 2000 Wiley-Liss, Inc.