What is the primary purpose of a plastic instrument in dental procedures?

The primary purpose of a plastic instrument in dental procedures is to pack resin material. These instruments are designed with a smooth, non-stick surface that allows for precise manipulation of various types of dental materials, particularly composite resins. The ability to effectively pack resin into cavities or around restorations is crucial for ensuring that the material adheres properly and achieves the desired aesthetic and functional outcomes.

In this context, the tool is specifically tailored for handling materials that require careful placement without introducing unwanted texture or air bubbles. This makes it an essential instrument in restorative dentistry, where the quality of the finished restoration is largely dependent on the correct application of resin materials.

Other options, while relevant to dental procedures, do not align with the specific design and intended utility of a plastic instrument. For example, the hardening of sealing materials typically involves curing lights or other techniques rather than a packing tool, and functions like removing plaque or separating teeth are better suited to different instruments designed explicitly for those purposes.