What happens to plaque that is not removed?

When plaque is not removed from the teeth and gums, it can lead to a process called calcification. Over time, the soft plaque that accumulates on the teeth interacts with minerals present in saliva. This interaction causes the plaque to harden and transform into calculus, also known as tartar. Calculus is significantly more difficult to remove than plaque and can contribute to dental problems such as gum disease and cavities if not professionally cleaned.

The other choices describe processes that either do not occur or are ineffective in addressing plaque. Plaque is not simply washed away by saliva, nor does it remain unchanged indefinitely, as it actively undergoes changes when left undisturbed. Similarly, it does not dissolve in the mouth, as plaque is a biofilm that requires mechanical removal through brushing and flossing. Thus, the transformation of plaque into calculus highlights the importance of regular dental hygiene practices.