Calculus is calcified dental plaque, commonly called tartar, and subgingival calculus is tartar found on the roots of the teeth below the gumline.

tartar

The hardened deposits that form on the teeth and can irritate the surrounding tissue, is called tartar or dental calculus. If good oral hygeine is not practiced, tartar can build up on the teeth and become hardened. This can irritate the gums and cause them to bleed.

Tools of dental hygienist include: dental lasers for teeth whitening and cleaning, dental and scalers to remove plaque and tartar and motorized dental polishers, according to the Occupational Information Network. Hygienists may also operate dental X-ray machines or use syringes to administer anesthetics.

Trident Gum was not named for Poseidon's Trident.

The original Trident gum was made to contain three enzymes which were thought to soften dental tartar, so the name Trident comes from three enzymes (Tri) to promote dental health (dent).