The science and art of dermal fillers for soft-tissue augmentation.(ORIGINAL ARTICLES)(Report)

ABSTRACT

Our expanding understanding of the physiological and immunological conditions of the skin and, in particular, the aging face, has prompted a growing field of aesthetic technology. Restorative procedures are taking advantage of improved and refined biotechnology, which continues to evolve at a rapid pace. Whereas surgical correction of skin laxity was the norm in years past, there are now many topical options available to encourage healthy, youthful skin, and an ever-growing, increasingly perfected depot of minimally invasive, injectable dermal volumizers and stimulators, collectively referred to as dermal fillers. The growth indicators for this market are as striking as the science. However, successful use of dermal fillers is not only a function of the quality of science leading to improved biocompatibility but also the "art" of client selection, filler application and vigilant follow up. Even the "ideal" filler is subject to unique interactions with both the practitioner and the patient. This article presents a review of the safety and efficacy of the most commonly used dermal fillers with emphasis on those approved for facial aesthetics. The subtleties of improved filler technologies that impact tissue acceptance and reaction, measures of effectiveness and a comparison of wrinkle-reduction outcomes, the nature and incidence of acute and chronic tissue reaction, and a discussion of recommended or preferred filler applications are presented.

INTRODUCTION

Injectable dermal fillers are rapidly challenging and complementing the market of more invasive cosmetic surgical procedures. Soft-tissue filler product technology expanded, and product use increased, by nearly 300,000 procedures in 2007 compared to 2006, according to the American Society of Plastic Surgeons. Collagen and fat injections declined, while procedures with hyaluronic acid (HA), calcium hydroxylapatite, polylactic acid (PLA) and polymethyl-methacrylate (PMMA) all increased. Over one million procedures used HA products, up 35% over the previous year, making HA dermal fillers the second-most performed minimally invasive cosmetic procedure performed in 2007, after Botox[R]. (1) It is estimated that the global aesthetic filler market will grow to over $1 billion in 2010. (2)

Dermal fillers have different tissue-compatibility characteristics that determine their suitability for a variety of applications. Thus, no single filler is "ideal" for all applications. However, certain desirable filler qualities are generally accepted (Table 1). Safety is the first priority when it comes to filler products. In terms of safety, non-allergenicity is of highest importance, as allergic reactions were commonplace with the first injectable (collagen) products. For example, all fillers containing bovine collagen require skin testing for hypersensitivity before use. Atelomeric porcine collagen-derived products are not required to be skin-tested, but can still produce an acute or delayed allergic response, as can hyaluronic acid products, although this is very rare. (3)

 
TABLE 1 
 
Desirable Qualities of Dermal Fillers * 
 
        Safety                        Effectiveness 
 
No hypersensitivity        Flexible--ease of injection, good tissue 
                           contouring effect, accommodates ongoing 
                           skin aging changes 
 
Biocompatibility           Physiologic--degree of inflammatory 
                           response, duration of effect, autogenous 
                           collagen stimulation 
 
Acceptable inflammation    Easy to use--requires little to no 
                           preparation, stores at room temperature 
 
Nonmigratory, nonclumping  Reproducible technique and result 
 
Minimal pain               Cost effective FDA approved 
 
* Sengelmann R, Tull S. (46) 

TECHNOLOGY