Periodontology - Calculus

Dental calculus, also known as tartar, is hardened dental plaque that is caused by minerals in saliva and gingival crevicular fluid reacting with bacterial plaque that is found on the teeth. When this reaction occurs, the bacteria within plaque is killed, but when the plaque hardens into calculus and forms a rough surface on the teeth, this creates a perfect breeding ground for the formation of new bacterial plaque. As new plaque forms on calculus and then hardens, calculus builds up and leads to gingivitis, or inflammation in the gums. Calculus forms at and above the gumline and can also form below the gumline, in the narrow groove between the gum tissue and the teeth. In addition to chronic inflammation of the gums, calculus can lead to bad breath and can cause the gum tissue to recede. While brushing and flossing can remove dental plaque from the surfaces of the teeth, it cannot remove dental calculus, which is too hard to remove with a toothbrush. Dental calculus can only be removed by a dental health professional with a hand tool or an ultrasonic tool.

Calculus is made up of mineral and organic components. The main mineral in calculus is calcium phosphate, and the organic element is both cellular and extracellular matrix, including bacteria, yeast, proteins, and lipids. There are also trace amounts of microscopic debris in calculus, including salivary protein, plant DNA, caseins, starches, textiles, and smoke particles. Calculus above the gumline, or supragingival calculus, is more prevalent on the exterior surfaces of the teeth in the upper jaw that are nearest the cheeks, and on the interior surfaces of the incisors in the lower jaw. Dental calculus hardens in layers during periodic calcification events, but it is unclear what triggers these events. Factors that influence the development of dental calculus include age, gender, diet, location in the mouth, oral hygiene, ethnic background, access to care, disabilities and diseases, drugs and medications, tobacco use, and the genetics of the host.

When calculus causes the tissues of the gums to become inflamed, this inflammation is called gingivitis. When gingivitis progresses and the connective tissues that attach the gums to the teeth and bone are affected, the disease is called periodontitis. While plaque is not the only cause of periodontitis, it is a primary cause. Any plaque that is allowed to remain on the teeth will eventually harden into calculus, and calculus encourages the formation and accumulation of further plaque. Calculus is therefore also considered a cause of periodontitis. Subgingival calculus secretes proteins that lead to inflammation of the periodontium, and this inflammation leads to loss of bone and weakening of the attachment fibers that hold the teeth into the gums. This attachment loss is a significant marker of periodontitis.

The word “calculus” is derived from the Latin word for “small stone” and has been used historically to refer to a variety of types of stones. Because stones have been used throughout history for mathematical purposes, the word has come to be used in mathematical contexts. “Calculus” also refers to mineral buildups in the human body, including kidney stones and dental calculus. The word “tartar,” which refers to the same dental mineral deposit as “calculus,” is derived from the Greek instead of the Latin and came to be used to describe the dental buildup of hardened calcium phosphate in the early 1800s.