What function does a flat plastic serve in dentistry?

In dentistry, a flat plastic serves primarily to remove excess filling materials. This tool is designed with a flat surface that allows for precision in managing and shaping dental materials, such as composite resins. After a cavity has been filled, it's crucial to ensure that there is no excess material that could affect the bite or retention of the filling. The flat plastic can effectively adjust the filling to sit comfortably and securely within the tooth, providing a smooth finish and ensuring proper occlusion.

The effectiveness of a flat plastic in this role is due to its design, which allows dental professionals to meticulously trim and contour filling materials without disturbing the surrounding tooth structure. This careful manipulation contributes to the overall success of restorative procedures and enhances patient comfort.

The other options proposed do not accurately reflect the intended use of a flat plastic in dental practice. Cleaning dental tools, filling cavities, or creating space between teeth involves different instruments and techniques suited for those specific tasks.