How much is injected when using local infiltration?

• A. 0.6–0.9 ml (1/3–1/2 of cartridge)
• B. 1.5–2.0 ml
• C. 0.1–0.2 ml
• D. 2.0–2.5 ml

Answer: (A)

Local infiltration relies on delivering a small amount of anesthetic directly into the tissue around the target area so the drug diffuses to nearby nerve endings. Because you’re numbing a localized space, only a fraction of a cartridge is needed—about 0.6 to 0.9 mL, roughly one third to one half of a standard 1.8 mL cartridge. This small volume provides enough anesthesia for a localized area while minimizing tissue distortion and systemic uptake. Using much more (near a full cartridge) isn’t necessary for infiltration and could increase risk, while too little (0.1–0.2 mL) is unlikely to achieve adequate anesthesia.