title: Crystallography of supragingival and subgingival human dental calculus.
abstract: Selected area electron diffraction of sections and individual crystal fragments of human dental calculus has demonstrated that octacalcium phosphate, hydroxyapatite and whitlockite form the inorganic part of both supragingival and subgingival dental calculus. However, the major constituents in supragingival calculus are platelet-shaped crystals of octacalcium phosphate and needle-shaped crystals of hydroxyapatite, while bulk crystals of whitlockite is the predominant component in subgingival calculus. The subgingival samples seemed to be better crystallized than the supragingival ones. The results obtained by the electron optical and X-ray powder investigations are in good agreement.
authors.forename: M
authors.initials: M
authors.lastname: Sundberg
authors.forename: J
authors.initials: J
authors.lastname: Friskopp
mesh_terms: D002130:Calcium Phosphates / Q000032:analysis; D003460:Crystallization; D003461:Crystallography; D003728:Dental Calculus / Q000032:analysis* / Q000473:pathology; D017886:Durapatite; D005881:Gingiva; D006801:Humans; D006882:Hydroxyapatites / Q000032:analysis; D008854:Microscopy, Electron; D014961:X-Ray Diffraction
chemical_list: D002130:Calcium Phosphates; D006882:Hydroxyapatites; C022045:octacalcium phosphate; C021767:whitlockite; D017886:Durapatite; C494366:calcium phosphate, dibasic, dihydrate