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Updated: Oct 16, 2026
Biological Compatibility Profile on Biomaterials for Bone Regeneration
Published on: November 16, 2018
Prospective Intraindividual Split-face Histological Comparison of Poly-d,l-lactic Acid and Calcium Hydroxylapatite
1From the Kim-Jongseo Plastic Surgery Clinic, Seoul, Republic of Korea.
Background:
Poly-d,l-lactic acid (PDLLA) and calcium hydroxylapatite (CaHA) are injectable biostimulators increasingly used as skin boosters. Although both promote tissue regeneration, their comparative histological effects in humans remain poorly characterized, particularly regarding differential vascular, collagenous, and elastinrelated responses that may influence individualized treatment strategies and clinical decision-making.
Methods:
This institutional review board-approved prospective split-face pilot study included 3 female patients (6 cheeks) who received PDLLA injection on one side and CaHA injection on the contralateral side. Biopsies were obtained 3 months after injection from corresponding preauricular or temporal facial regions during the facelift procedure for histological and immunohistochemical evaluation, including hematoxylin and eosin, Herovici, Verhoeff-Van Gieson, and CD31/CD34 immunostaining. Ultrasound (33 MHz) and surface roughness analysis were also performed, alongside Global Aesthetic Improvement Scale scoring.
Results:
Both PDLLA and CaHA demonstrated regenerative activity, though their predominant effects differed. PDLLA was associated with greater angiogenesis (capillary counts and CD31 staining), fibroblast activation, and early collagen remodeling. CaHA exhibited higher elastin fiber density (13% increase by Verhoeff-Van Gieson staining), stronger CD34 expression, and more pronounced early dermal thickening on ultrasound. Both agents improved clinical skin roughness and Global Aesthetic Improvement Scale scores without major adverse events.
Conclusions:
PDLLA and CaHA skin boosters each demonstrated distinct yet beneficial biostimulatory profiles in human tissue. PDLLA favored angiogenesis and collagen remodeling, whereas CaHA promoted elastogenesis, progenitor cell activation, and early tissue reinforcement. These findings highlight the complementary roles of PDLLA and CaHA and underscore the need for larger, long-term studies to refine their clinical applications.
