Final answer:
Tungsten carbide inserts on needle holders are used to ensure a durable and secure grip on needles during suturing, benefiting from the material's hardness and resistance to wear.
Step-by-step explanation:
The purpose of a tungsten carbide insert on a needle holder is to provide a more durable and secure grip on the needle during suturing procedures. Tungsten carbide is a very hard material that resists wear and provides excellent gripping power. The inserts are typically cross-hatched or have a textured surface, which further enhances their ability to hold the needle firmly without it slipping or rotating, even after repeated use. This is particularly important in surgical procedures where precision and reliability are crucial.