I can see a dark spot between my teeth. Is it a cavity?

A dark spot between the teeth can be either a cavity or simple staining, and it is hard to tell by eye alone. Staining is pigment from coffee, tea, or smoking sitting on the surface and comes off with scaling, whereas a cavity burrows beneath the surface and keeps growing. Cavities between the teeth often look like a small dot from the outside while extending widely inside, so an X-ray is needed. If any of these applies - 1) floss often catches or shreds there, 2) it feels sensitive to sweet foods, or 3) the spot keeps getting bigger - we recommend an examination soon.