title: Introduction to Fillers.
abstract: BACKGROUND
  Over the last few years, injectable soft-tissue fillers have become an integral part of cosmetic therapy, with a wide array of products designed to fill lines and folds and revolumize the face.
  
  
  METHODS
  This review describes cosmetic fillers currently approved by the Food and Drug Administration and discusses new agents under investigation for use in the United States.
  
  
  RESULTS
  Because of product refinements over the last few years-greater ease of use and longevity, the flexibility of multiple formulations within one line of products, and the ability to reverse poor clinical outcomes-practitioners have gravitated toward the use of biodegradable agents that stimulate neocollagenesis for sustained aesthetic improvements lasting up to a year or more with minimal side effects. Permanent implants provide long-lasting results but are associated with greater potential risk of complications and require the skilled hand of the experienced injector.
  
  
  CONCLUSIONS
  A variety of biodegradable and nonbiodegradable filling agents are available or under investigation in the United States. Choice of product depends on injector preference and the area to be filled. Although permanent agents offer significant clinical benefits, modern biodegradable fillers are durable and often reversible in the event of adverse effects.
authors.affiliation: Vancouver, British Columbia, Canada From the Department of Ophthalmology and Visual Sciences, University of British Columbia; and Department of Dermatology and Skin Science, University of British Columbia.
authors.forename: Jean
authors.initials: J
authors.lastname: Carruthers
authors.forename: Alastair
authors.initials: A
authors.lastname: Carruthers
authors.forename: Shannon
authors.initials: S
authors.lastname: Humphrey
mesh_terms: D001672:Biocompatible Materials / Q000008:administration & dosage*; D003357:Cosmetic Techniques; D004954:Esthetics; D006801:Humans; D007271:Injections, Intradermal; D012060:Rejuvenation; D015595:Skin Aging / Q000187:drug effects*
chemical_list: D001672:Biocompatible Materials