For interproximal margins, it is critical that they:

The importance of interproximal margins following the soft tissue contour lies in their role in preserving periodontal health and ensuring effective cleaning. When the margins of a restoration adhere to the natural contours of the soft tissue, it facilitates a more natural relationship with the surrounding gums and helps to prevent food impaction and plaque accumulation. This alignment reduces the risk of irritation and inflammation of the gingival tissue, contributing to overall periodontal stability.

In contrast, placing interproximal margins beyond the gingival tissue could potentially lead to exposed areas that are harder to clean, increasing the likelihood of decay or periodontal issues. Placing them far from the tooth midline could result in poorer aesthetics and function, while aligning with the occlusal plane addresses function more than interproximal health, which is not the primary concern of interproximal margins. Therefore, ensuring that interproximal margins follow the soft tissue contour is vital for both health and function within restorative dentistry.