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  1. 1. Hai friends
  2. 2. CEMENTUM
  3. 3. DEFINITION Cementum is the calcified a vascular mesenchmal tissue that forms the outer layer cover of the anatomic root Types of cementum There are two main types of cementum they are:- 1.A celluar cementum and 2.cellular cementum The two main source’s of collagen fibers in cementum are sharpey’s fibers which are the embedded portion of principal fibers of the
  4. 4.  Periodontal ligament and are formed by the fibroblasts Fibers that belong to cementum matrix and are produced by cementoblasts Cementoblasts also form the non collagenous components of the inter fibrillar ground substance such as proteoglycans, glycoproteins and phosphoproteins Proteoglycans are the most likely to play a role in regulating cell-cell and cell-matrix interactions
  5. 5. COMPOSTION The major proportion of the organic matrix of a cementum is composed of type one (90%) and type three about (5%) collagens ACELLULAR CEMENTUM It is the first cementum formed, covers approximately the cervical third or half of the root and does not contain cell’s
  6. 6.  This cementum is formed before the tooth reaches the occlusal plane and it’s thickness ranges froms 30 to 230 um Sharpey’s fibers are completely calcified, with the mineral crystals. Oriented parallel to the fibrils as dentin and bone except in a 10 -50 um wide zone near the cementodentinal junction where they are only partially calcified
  7. 7. •Acellular cementum also contains intrinsic collagen fibrilsthat are calcified and irregularly arranged or parallel to thesurface•CELLULAR CEMENTUM•Celluar cementum formed after the tooth reaches theocclusal plane is more irregular and contain cell’s(cementocytes) in individual spaces (lacunae)
  8. 8. that communicate with each other through asystem of anastomising canaliculiCellular cementum is less calcified than theacellular typeSharpey’s fibers occupy a smaller portion ofcellular cementum and are separated by other fibersthat are arranged either parallel to the root surfaceBoth acellular and cellular cementum are arangedin lamellae separated by incremental lines parallelto long axis root this lines are called rest periods
  9. 9. PERMEABILITY OF CEMENTUM In very young animal’s acellular cementum and cellular cementum are very permeable and permit the diffusion of dyes from the pulp and external root suface THICKNESS OF CEMENTUM Cementum deposition is a continuous process that proceeds at varying rates
  10. 10.  Cementum formation is most rapid in theapical regions where it compensates fortooth eruption, which it self compensate forattrition The thickness of cementum on the coronalhalf of the root varies from 16-60um It attains greatest thickness (upto 150-200um) in the apical third and in the fraction areas Abnormalities in the thickness of cementummay range from an absence of cellularcementum to an excessive deposition of
  11. 11. The term hyper cementosis refers to a prominentthickening of cementumHyper cementosis occurs a generalisied thickening ofthe cementumCEMENTUM RESORPTION AND REPAIRCementum resorption may be caused by local andsystemic factors
  12. 12.  Local condition causing cementum resorptioninclude trauma from occlusion orthodonticmovement pressure from malaligned erupting teethcysts and tumors teeth with out junctionalantagoinsts Systemic condition citied as predisposing to orincluding cemental resorption include calciumdeficiency hypothyroidism, hereditary fibrousosteodystrophy
  13. 13.  Cementum becomes exposed to the oralenvironment in cases of gingival recession and asresult of loss of attachment in pocket formation CEMENTO ENAMEL JUNCTION The cementum at and immediately subjacent tocemento enamel junction is of particular clinicalimportance in root scaling procedures
  14. 14. Three types of relationships involving thecementum may exists at cementoenamel junction In about 60 -65% of cases, cementum over laps theenamel in about 30% an edge-edge but joint existsand 5-10% the cementum and enamel fail to meetCEMENTO DENTINAL JUNCTIONThe terminal apical area of cementum where itjoins the internal root canal dentin is known ascemento dental junction
  15. 15. THANK YOU SUBMITTED BY yuvaraj…… yuvamusic2009@gmail.com