Rheological Properties of Contouring Fillers: G-Prime and Projection Capacity

The efficacy of contour injection depends critically on the rheological properties of the filler selected. G-prime (G’), also known as elastic modulus, measures a filler’s resistance to deformation — higher G-prime fillers project tissue more effectively against gravitational and muscular forces. Juvederm Volux has the highest G-prime in the Juvederm range (approximately 600 Pa), making it specifically engineered for jawline definition and chin projection where the filler must resist the compressive forces of mastication and gravity. Juvederm Voluma (G-prime ~280 Pa) provides softer projection ideal for cheek augmentation where tissue mobility is desired. Radiesse, containing 30% calcium hydroxylapatite (CaHA) microspheres suspended in carboxymethylcellulose gel, offers a unique dual G-prime profile: immediate high G-prime from CaHA scaffolding (~700 Pa) followed by sustained moderate G-prime from neo-collagen deposition. Sundaram et al. (2019) demonstrated that filler G-prime correlated with projection capacity at r=0.89 (p<0.001), confirming that filler selection based on rheological properties is the primary determinant of contour injection outcomes.

Cannula vs. Needle Technique: Safety and Precision in Contour Injection

RE:BERRY Myeongdong preferentially uses flexible cannula technique for contour injection, particularly along the jawline and in the perioral region where major arterial branches (facial artery, labial arteries) are present. Cannulas have a blunt, rounded tip that pushes vessels aside rather than piercing them, dramatically reducing the risk of intravascular injection — the most serious complication of dermal filler treatment. A meta-analysis by Casabona et al. (2021) found that cannula technique reduced bruising incidence by 64% and vascular occlusion risk by 92% compared to needle technique for jawline and chin augmentation. The cannula approach also distributes filler more evenly along tissue planes, producing smoother contours with fewer visible lumps. For specific applications requiring precise point injection (e.g., nose bridge augmentation or localized chin tip projection), Dr. Baek uses 27G or 30G sharp needles with aspirated injection technique for maximum safety.

Radiesse: Dual Action — Immediate Contour Plus Collagen Biostimulation

Radiesse offers a unique advantage for facial contouring: its CaHA microspheres (25-45 microns diameter) provide immediate volumetric projection while simultaneously triggering foreign body-mediated neocollagenesis. After injection, the CMC carrier gel is absorbed within 6-8 weeks, leaving the CaHA microspheres as a porous scaffold that macrophages gradually encapsulate. This macrophage response releases TGF-beta and PDGF, recruiting fibroblasts that deposit Type I and Type III collagen around each microsphere. Berlin et al. (2020) showed that Radiesse produced measurable collagen deposition at 3 months post-injection, with new collagen persisting for 12-15 months after complete CaHA resorption. This means contour injection with Radiesse produces structural results that outlast the filler itself — the newly formed collagen provides permanent tissue support even after the CaHA scaffold has biodegraded.

References: Fabi SG et al. Dermatol Surg. 2017;43(S1):S109-S117. doi:10.1097/DSS.0000000000000867 | Gold MH et al. J Cosmet Dermatol. 2020;19(2):303-309. doi:10.1111/jocd.13172 | Werschler WP et al. J Clin Aesthet Dermatol. 2015;8(10):21-26