FAC Materials & Techniques 2 — Questions and Answers
Question 1: Which hyaluronic acid filler property is most associated with resistance to deformation under pressure?
- Cohesivity (Correct answer)
- Hydrophilicity
- Viscosity
- Elasticity
Correct answer: Cohesivity
Cohesivity refers to the cross-linked gel's ability to maintain shape and resist fragmentation under mechanical stress.
Question 2: Calcium hydroxylapatite (CaHA) fillers differ from hyaluronic acid fillers primarily because they:
- Are reversible with hyaluronidase
- Stimulate neocollagenesis over time (Correct answer)
- Have a shorter duration of effect
- Are only used in the lips
Correct answer: Stimulate neocollagenesis over time
CaHA microspheres act as a scaffold that stimulates fibroblasts to produce new collagen, providing biostimulatory effects beyond initial volume.
Question 3: When reconstituting botulinum toxin type A, which diluent is universally recommended?
- Sterile water for injection
- Bacteriostatic normal saline (Correct answer)
- Lactated Ringer's solution
- Dextrose 5% in water
Correct answer: Bacteriostatic normal saline
Bacteriostatic normal saline (0.9% NaCl with benzyl alcohol) is preferred because benzyl alcohol provides mild anesthesia and preserves the toxin.
Question 4: The 'fern pattern' technique in thread lifting refers to:
- Placement of barbed threads in a branching configuration (Correct answer)
- A PDO mesh used under the dermis
- Cog thread insertion along the SMAS
- Multiple mono threads placed parallel to wrinkles
Correct answer: Placement of barbed threads in a branching configuration
The fern pattern describes deploying barbed threads in diverging directions from a single entry point to maximize tissue lifting coverage.
Question 5: Which characteristic distinguishes a biphasic HA filler from a monophasic one?
- Biphasic fillers contain two cross-linked HA phases mixed together (Correct answer)
- Biphasic fillers use no cross-linking agents
- Biphasic fillers dissolve faster with hyaluronidase
- Biphasic fillers are only appropriate for superficial lines
Correct answer: Biphasic fillers contain two cross-linked HA phases mixed together
Biphasic fillers consist of distinct cross-linked HA particles suspended in a non-cross-linked HA carrier gel, giving different lift and spreadability properties.
Question 6: Poly-L-lactic acid (PLLA) biostimulator requires multiple treatment sessions primarily because:
- It dissolves within 48 hours and must be replaced
- Its collagen-stimulating effect builds gradually over months (Correct answer)
- It contains lidocaine that wears off quickly
- It migrates from the injection site after each session
Correct answer: Its collagen-stimulating effect builds gradually over months
PLLA triggers a delayed fibroblast response, so collagen production accumulates progressively, requiring staged treatments 4–6 weeks apart.
Question 7: In the context of dermal fillers, 'G prime' (G') measures:
- The filler's ability to attract water
- The elastic stiffness or firmness of the gel (Correct answer)
- The concentration of cross-linking agent
- The degradation rate by hyaluronidase
Correct answer: The elastic stiffness or firmness of the gel
G prime is the storage modulus representing the gel's elastic stiffness, which determines its lift capacity and resistance to dynamic movement.
FAC Materials & Techniques 2
Which hyaluronic acid filler property is most associated with resistance to deformation under pressure?