Evolution of the Clinical Use of Hyaluronic Acid Fillers

ology of rheologic studies and discussed their value and limitations. This second article presents data from recent rheologic studies of hyaluronic acid and calcium hydroxylapatite fillers and discusses how these data correlate with our current understanding and use of these fillers. Rheology—the study of flow-related properties—has been recognized for almost a century as being relevant to a number of fields, including materials science, geophysics, and pharmaceutics. Rheologic theory and measurements are considered critical for the manufacture of topical medications, paints and inks, concrete, and even chocolate. The discovery that rheology could shape and guide our clinical use of soft tissue fillers was serendipitous.