Trace amounts of host, dietary, and environmental microdebris are also found within calculus, including salivary proteins, plant DNA, milk proteins, starch granules, textile fibers, and smoke particles. Calculus formation
The processes of calculus formation from dental plaque are not well understood. Supragingival calculus formation is most abundant on the buccal (cheek) surfaces of the maxillary (upper jaw) molars and on the lingual (tongue) surfaces of the mandibular (lower jaw) incisors. These areas experience high salivary flow because of their proximity to the parotid and sublingual salivary glands. Subgingival calculus forms below the gumline and is typically darkened in color by the presence of black-pigmented bacteria, whose cells are coated in a layer of iron obtained from heme during gingival bleeding. Dental calculus typically forms in incremental layers that are easily visible using both electron microscopy and light microscopy. These layers form during periodic calcification events of the dental plaque, but the timing and triggers of these events are poorly understood. The formation of calculus varies widely among individuals and at different locations within the mouth. Many variables have been identified that influence the formation of dental calculus, including age, gender, ethnic background, diet, location in the oral cavity, oral hygiene, bacterial plaque composition, host genetics, access to professional dental care, physical disabilities, systemic diseases, tobacco use, and drugs and medications. Clinical significance
Plaque accumulation causes the gingiva to become irritated and inflamed, and this is referred to as gingivitis.
Xanthoma diabeticorum is a cutaneous condition that may result in young persons who are unresponsive to insulin. : 534

See also
Xanthoma
Skin lesion


== References ==