CALCULUS

Definition Classification Prevalence Composition Attachment to tooth surface Formation Theories of mineralization Significance

Dental plaque is defined as the soft deposits that form the biofilm adhering to the tooth surface or other hard surfaces in the oral cavity, including fixed and removable restorations.

Calculus is a hard deposit that forms by mineralization of dental plaque and is generally covered by a layer of dental plaque.

Classification According to its relation to

gingival margin – supra gingival sub gingival

Composition Inorganic content Organic content

Supra gingival calculusInorganic content (70%-90%) 75.9% calcium phosphate 3.1%calcium carbonate traces of magnesium phosphate ⅔ in crystalline form -Hydroxyapatite -Magnesium whitlockite -Octacalciumphosphate -Brushite

Organic content Protein polysaccharide -1.9% - 9.1% carbohydrate -5.9%-8.2% proteins -0.2% lipids Desquamated epithelial cells Leukocytes Micro – organisms

Sub gingival calculus

Similar to supra gingival calculus with difference in

-ratio of crystalline structure -calcium to phosphate ratio -protein content -sodium content

Attachment to the tooth surface Organic pellicle Mechanical locking Close adaptation Penetration of calculus bacteria

into cementum

Formation Dental plaque undergoes

mineralization to form calculus Source Supra gingival - saliva Sub gingival - serum Role of micro-organisms

Theories of mineralization of calculus

Mineral precipitation resulting from a local rise in the degree of saturation of calcium and phosphate ions.

Seeding agents- induce small foci of calcification that enlarge and coalesce to form a calcified mass.

Significance