Introduction

The modern history of soft-tissue augmentation began in the late 1800s, with the use of transplanted fat to correct a cosmetic deformity. Since that time, physicians have worked with many substances in a quest to identify the ideal filler substance (Table 1).

Table 1. Characteristics of the Ideal Dermal Filler^[1,2]

Despite widespread research in the developing field of aesthetic medicine, progress toward a viable commercial facial filler was slow. At the inception of my career in the late 1970s, many facial filling products and techniques had been proposed and researched worldwide, but none had received US Food and Drug Administration (FDA) approval. As a resident at Stanford University, I participated in the large-scale clinical trials evaluating the safety and effectiveness of bovine collagen in aesthetic applications. In 1981, after 6½ years of study by more than 700 physician investigators, the FDA approved Zyderm^® 1.

This approval was a milestone -- the first injectable substance approved for soft-tissue augmentation. The success of Zyderm^® stimulated the development of additional fillers, including refined forms of bovine collagen, autologous fat, and early versions of alloplastic injectable and surgically implanted materials. Each had positive attributes but ultimately fell short of ideal due to immunologic, cost, or ease-of-use concerns. Despite widespread research, injectable collagen remained the only commercial therapeutic filler option for more than 20 years.

FDA approval of the first hyaluronic acid (HA) dermal filler in 2003 (Restylane^®; Medicis Pharmaceutical Corporation; Scottsdale, Arizona) was a breakthrough in augmentation treatment. Approved HA products are easy to use, demonstrate longer-lasting results than collagen predecessors, and do not require pretreatment allergy testing.

In recent years, additional innovations in dermal-filling technology have led to the development of products that stimulate a biological response to the injected product, leading to gradual dermal thickening and a longer duration of effect. Fillers using this technology have in effect moved beyond the term "filler," because their results are not derived from the volume of product injected but from the long-term stimulation of the patient's own collagen production.

The rapid product breakthroughs in aesthetic medicine over the past 10 years have enabled a similar evolution in the approach to aesthetic rejuvenation. In general, aesthetic treatment with dermal fillers has moved from a 2-dimensional focus on the treatment of individual lines and wrinkles to an awareness of the possibilities of a 3-dimensional perspective on rejuvenation.^[3] Gravity, fat redistribution,^[4] dermal thinning, bone resorption,^[5] and loss of elasticity and collagen in the skin^[6] are critical factors in the outward appearance of aging. The contemporary standard of care is to treat the face from "the inside out,"^[6] and the breadth of today's product options makes this an exciting and realistic possibility.

Today, the quest for the ideal dermal filler is enhanced by the knowledge that "ideal" is a complex concept that must account for many variables, including a filler's scientific profile and physical attributes, the patient's goals and physiology, and the physician's experience. As with other cosmetic treatments, a one-size-fits-all approach to soft-tissue augmentation will not yield optimal results. As dermal-filling options continue to change and expand, the effective clinician must understand the unique properties and characteristics of each product and apply that knowledge to the crafting of an individual treatment plan for each patient.