Which auxiliary aid is specifically designed for interproximal cleaning?

Interdental brushes are specifically designed for interproximal cleaning due to their unique structure that allows them to effectively clean between teeth. These brushes have a narrow design with bristles that can easily reach and remove plaque and debris from the areas between adjacent teeth where traditional toothbrushes may not reach effectively. Their design accommodates different sizes of interdental spaces, making them versatile for various oral anatomies.

While toothpicks in a holder can be used to clean interproximal areas, they are not as effective as interdental brushes for thorough cleaning, especially in terms of plaque removal. Gauze can be used for various purposes but does not specifically target the interproximal spaces, as it is more suited for general cleaning or drying. Polishing strips, although useful for surface polishing, do not provide the same level of cleaning between teeth as interdental brushes do. Thus, interdental brushes are the optimal choice for ensuring effective interproximal cleaning, making them the correct answer.