Which instrument is used to mix and dispense impression material?

The extruder gun is the correct instrument used to mix and dispense impression material. This tool features a mechanism that allows for the controlled application of impression material onto a tray or directly onto the dental arch. Its design enables the user to efficiently mix two components of certain impression materials, particularly those that come in cartridges, ensuring that the material is homogeneously blended for optimal results.

The extruder gun's functionality is key in achieving the accurate consistency needed for effective impressions, which are crucial for creating dental restorations, models, or dentures. As the material is dispensed, it fills in the details of the oral structures, leading to precise replicas that can be used for further dental procedures.

Other instruments listed, such as the lab knife, flexible mixing bowl, and denture case, serve different purposes in dental practice. The lab knife is generally used for cutting, trimming, or shaping materials, while the flexible mixing bowl is designed for mixing various dental materials but does not dispense them. The denture case is simply a storage container for dentures and does not have a role in the mixing or dispensing process.