Final answer:
When using an extruder gun, the impression material is mixed in the mixing tip, providing a bubble-free mixture for dental impressions.
Step-by-step explanation:
When an extruder gun is used in dental practices, the impression material is mixed in the mixing tip as it passes through, allowing for a homogeneous and efficient mixture. The extruder gun dispenses the base and catalyst components of the impression material, which are then mixed together dynamically in the mixing tip as they are extruded out of the gun. This provides a consistent and bubble-free mixture that is ready for immediate use in dental impressions.