Calculus

Dental calculus is more commonly known as tartar and is dental plaque in its hardened form. While this hardened form of bacterial plaque does not contain bacterial cells, which die when plaque hardens, dental calculus forms a rough surface on the teeth, and this uneven surface attracts additional plaque and can be difficult to effectively clean, which causes dental calculus to accumulate in layers over time. When calculus builds up on the teeth, the health of the gum tissue is compromised, and this accumulation of calculus also causes bad breath, receding gums, and inflammation in the soft tissues of the mouth. Calculus can form above the gumline, of course, but it can also form below the gumline, in the narrow crevice of potential space between the gums and the teeth. This crevice is called the gingival sulcus, and calculus that accumulates there is known as subgingival calculus. Brushing and flossing routinely and correctly can remove plaque from the surfaces of the teeth, but it can be difficult to reach the small space within the gingival sulcus to remove plaque. Additionally, once it hardens, calculus cannot be removed with toothbrushes and floss and must instead be removed by a dental health provider using professional tools.

Calculus is made of about equal parts of mineral matter and organic matter, though the specific composition depends on where in the mouth the calculus is found. The primary mineral in calculus is calcium phosphate, and the organic matter in calculus is primarily bacterial, though calculus also contains extracellular material that can include salivary protein, food debris, and small particles of textile fibers and smoke. Dental calculus forms at different rates and based on different triggers from person to person, and the process of calculus development is not thoroughly understood. Many factors are believed to contribute to individual characteristics of calculus formation, including gender, age, ethnicity, diet, oral hygiene, location in the mouth, the composition of bacterial plaque, genetics of the host, disabilities and systemic diseases, tobacco, and certain medications.

Plaque forms on the teeth nearly constantly and is exacerbated by interaction with sugars and starches in the diet, which is why it is recommended to clean the teeth at least twice daily, if not more frequently. When plaque is allowed to accumulate, this accumulation causes inflammation of the gum tissues, which is known as gingivitis. Gingivitis is reversible, and inflammation may be reduced or eliminated with a thorough dental cleaning. If the inflammation of gingivitis is not addressed, however, it can lead to periodontitis. Periodontitis is characterized by detachment of the connective tissue fibers that hold the teeth in place, which can eventually lead to tooth loss and bone resorption. This detachment leads to pocket formation in the gums, as the spaces of the gingival sulcus increase with inflammation and attachment loss. Larger pockets in the periodontium provide more room for plaque to accumulate and harden into calculus, and the cycle of damage from periodontitis is allowed to continue. Calculus above the gumline is common in all humans and, when the rest of the mouth is healthy, can be removed during professional cleanings, helping to discourage the formation and accumulation of calculus. Calculus below the gumline is more difficult to remove and is often indicative of irreversible gum disease. It must still be managed, however, to prevent continued destruction of the periodontium and possibly loss of the teeth and resorption of bone.