a hard deposit of calcified plaque which is found around the neck of the tooth. When it is above the free gingival margin (supra-gingival) it is white and chalky. When it is below (sub-gingival) it is dark and hard.
Found on http://www.encyclo.co.uk/local/20169
(from the article `mineral`) ...extent of organically formed aragonite. Minerals also are produced by the human body: hydroxylapatite [Ca5(PO4)3(OH)] is the chief component of ... Found on http://www.britannica.com/eb/a-z/c/6
branch of mathematics concerned with the calculation of instantaneous rates of change (differential calculus) and the summation of infinitely many ... [23 related articles] Found on http://www.britannica.com/eb/a-z/c/6
(mathematics) Branch of mathematics which uses the concept of a derivative to analyse the way in which the values of a function vary. Calculus is probably the most widely used part of mathematics. Many real-life problems are analysed by expressing one quantity as a function of another ... Found on http://www.talktalk.co.uk/reference/encyclopaedia/hutchinson/m0006648.html
Calculus is the hard residue ranging from yellow to brown forming on teeth when oral hygiene is incomplete or improper. Calculus is formed from Plaque (a soft sticky substance that accumulates on teeth; composed largely of bacteria and food substances suspended in saliva) which can build up and become hard. This hard plaque is known as tartar or ca... Found on http://www.dentalfind.com/info/calculus