Physiochemical Characteristics of Calcium Hydroxylapatite (CaHA)

The clinical performance of fillers in soft tissue augmentation depends upon their physiochemical properties, anatomical areas injected, interaction with the recipient, and the skill and experience of the physician. Scientific measures of filler properties facilitate appropriate selection of treatments for optimal treatment outcomes, and inform adjustments to treatments that improve patient safety and aesthetic outcomes. The rheological properties of calcium hydroxylapatite (CaHA), elastic modulus (G') and viscosity, coupled with its capacity to offer both immediate results and continued stimulation of collagen type I deposition, support its distinction as an ideal treatment for the volume loss characteristic of aging. Furthermore, the comparatively higher G' of CaHA offers a physiochemical basis for the clinical performance observed by the authors, especially in regions such as the temple and chin, where the force exerted by CaHA against bone permits expansion of overlaying tissue, permitting it to behave as a liquid implant.