Also known as tartar or calculus, calcium deposits are hardened patches of plaque that form on the teeth. Plaque is a naturally occurring layer of bacteria found on tooth enamel. If allowed to remain—as in when you don’t have world class dental hygiene—it progresses to form visible calcium deposits.

Dental plaque is a soft layer of proteins and bacteria (called a biofilm) that accumulate on the surface of teeth in between brushing and flossing.
Dental plaque can be defined as the soft deposits that form the biofilm ... Below is a summary of the bacteria that may be present during the plaque.
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