0
CEMENTUMCEMENTUM
INTRODUCTIONINTRODUCTION
 Is mineralized dental tissue covering the anatomic
roots of human teeth.
 Begins at cervical p...
3
THICK CEMENTUM ON ROOT APICESTHICK CEMENTUM ON ROOT APICES
IN AN ELDERLY PERSONIN AN ELDERLY PERSON
4
PHYSICAL CHARACTERSTICSPHYSICAL CHARACTERSTICS
Hardness is less than that of dentin.
Light yellow in color.
Can be dist...
CHEMICAL COMPOSITIONCHEMICAL COMPOSITION
Contains 45% to 50% inorganic
substances & 50% to 55% organic
material & water.
...
Cellular components of cementumCellular components of cementum
7
CEMENTOBLASTSCEMENTOBLASTS
Soon after Hertwig’s sheath breaks up,
undifferentiated mesenchymal cells from adjacent
connec...
9
10
ULTRASTRUCTURE OF CEMENTOCYTEULTRASTRUCTURE OF CEMENTOCYTE
NEAR CEMENTUM SURFACE.NEAR CEMENTUM SURFACE.
11
ULTRASTRUCTURE OF CEMENTOCYULTRASTRUCTURE OF CEMENTOCY
DEEP IN CEMENTUMDEEP IN CEMENTUM
12
CEMENTOID TISSUECEMENTOID TISSUE
The uncalcified matrix is called cementoid.
Mineralization of cementoid is a highly ord...
14
Schroeder’s classificationSchroeder’s classification
Acellular afibrillar cementum
- Contains neither cells nor extrinsic...
Cellular intrinsic fiber cementum
- Contains cells but no extrinsic collagen fibers.
Formed by cementoblasts. It fills re...
 Cementum can be differentiated into: acellular & cellular
cementum.
 Acellular cementum does not have spiderlike cement...
Acellular cementumAcellular cementum
18
CELLULAR CEMENTUMCELLULAR CEMENTUM
19
INCREMENTAL LINESINCREMENTAL LINES
Are highly mineralized areas with
less collagen and more ground
substance than other p...
21
CEMENTODENTINAL JUNCTIONCEMENTODENTINAL JUNCTION
Smooth in permanent teeth.
Scalloped in deciduous teeth.
Dentin is sep...
23
CEMENTOENAMEL JUNCTIONCEMENTOENAMEL JUNCTION
In 60% of the teeth, cementum overlaps
the cervical end of enamel for a shor...
RELATION OF CEMENTUM TO ENAMELRELATION OF CEMENTUM TO ENAMEL
AT THE CEMENTOENAMEL JUNCTIONAT THE CEMENTOENAMEL JUNCTION
25
CLINICAL CONSIDERATIONSCLINICAL CONSIDERATIONS
Cementum is more resistant to resorption
than is bone, & it is for this re...
In most cases of repair, there is a tendency to re-establish
the former outline of the root surface by cementum.
This is ...
HYPERCEMENTOSISHYPERCEMENTOSIS
 Is an abnormal thickening of cementum.
 May be diffuse or circumscribed.
 May affect al...
Extensive hyperplasia of cementum is occasionally
associated with chronic periapical inflammation.
Hyperplasia of cement...
30
ATTACHED CEMENTICLES ON SURFACEATTACHED CEMENTICLES ON SURFACE
OF CEMENTUMOF CEMENTUM
31
THANK YOUTHANK YOU
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Cementum

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covering above root of Teeth

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Transcript of "Cementum"

  1. 1. CEMENTUMCEMENTUM
  2. 2. INTRODUCTIONINTRODUCTION  Is mineralized dental tissue covering the anatomic roots of human teeth.  Begins at cervical portion of the tooth at the cementoenamel junction & continues to the apex.  Furnishes a medium for the attachment of collagen fibers that bind the tooth to surrounding structures.  Makes functional adaptation of the teeth possible.  Unlike bone, human cementum is avascular. 2
  3. 3. 3
  4. 4. THICK CEMENTUM ON ROOT APICESTHICK CEMENTUM ON ROOT APICES IN AN ELDERLY PERSONIN AN ELDERLY PERSON 4
  5. 5. PHYSICAL CHARACTERSTICSPHYSICAL CHARACTERSTICS Hardness is less than that of dentin. Light yellow in color. Can be distinguished from enamel by its lack of luster & its darker hue. Semi-permeable to a variety of materials. 5
  6. 6. CHEMICAL COMPOSITIONCHEMICAL COMPOSITION Contains 45% to 50% inorganic substances & 50% to 55% organic material & water. Cementum has the highest fluoride content of all the mineralized tissues. Organic portion consists primarily of type I collagen & protein polysaccharides (proteoglycans). 6
  7. 7. Cellular components of cementumCellular components of cementum 7
  8. 8. CEMENTOBLASTSCEMENTOBLASTS Soon after Hertwig’s sheath breaks up, undifferentiated mesenchymal cells from adjacent connective tissue differentiate into cementoblasts. Synthesize collagen & protein polysaccharides which make up the organic matrix of cementum. Have numerous mitochondria, a well-formed golgi apparatus, & large amounts of granular endoplasmic reticulum. 8
  9. 9. 9
  10. 10. 10
  11. 11. ULTRASTRUCTURE OF CEMENTOCYTEULTRASTRUCTURE OF CEMENTOCYTE NEAR CEMENTUM SURFACE.NEAR CEMENTUM SURFACE. 11
  12. 12. ULTRASTRUCTURE OF CEMENTOCYULTRASTRUCTURE OF CEMENTOCY DEEP IN CEMENTUMDEEP IN CEMENTUM 12
  13. 13. CEMENTOID TISSUECEMENTOID TISSUE The uncalcified matrix is called cementoid. Mineralization of cementoid is a highly ordered event & not the random precipitation of ions into an organic matrix. Fibers are embedded in the cementum & serve to attach the tooth to surrounding bone. Their embedded portions are known as Sharpey’s fibers. 13
  14. 14. 14
  15. 15. Schroeder’s classificationSchroeder’s classification Acellular afibrillar cementum - Contains neither cells nor extrinsic or intrinsic collagen fibers, except for mineralized ground substance. Coronal cementum.(1-15um)  Acellular extrinsic fiber cementum - Composed almost entirely of densely packed bundles of Sharpey’s fibers. Cervical third of roots. (30-230um)  Cellular mixed stratified cementum - Composed of extrinsic & intrinsic fibers & may contain cells. Co-product of cementoblasts & fibroblasts. Apical third of roots, apices & furcation areas. (100-1000um) 15
  16. 16. Cellular intrinsic fiber cementum - Contains cells but no extrinsic collagen fibers. Formed by cementoblasts. It fills resorption lacunae.  Intermediate cementum - Poorly defined zone near the cementodentinal junction. Contains cellular remnants of Hertwig’s sheath embedded in calcified ground substance. 16
  17. 17.  Cementum can be differentiated into: acellular & cellular cementum.  Acellular cementum does not have spiderlike cementocytes incorporated into it.  Acellular cementum is found at the coronal half whereas the cellular cementum is found at the apical half.  Cementum is thinnest at the cementoenamel junction & thickest toward the apex.  Cementocytes are either degenerating or are marginally active cells. 17
  18. 18. Acellular cementumAcellular cementum 18
  19. 19. CELLULAR CEMENTUMCELLULAR CEMENTUM 19
  20. 20. INCREMENTAL LINESINCREMENTAL LINES Are highly mineralized areas with less collagen and more ground substance than other portions of the cementum. The thickness of cementum does not enhance functional efficiency by increasing the strength of attachment of the individual fibers. 20
  21. 21. 21
  22. 22. CEMENTODENTINAL JUNCTIONCEMENTODENTINAL JUNCTION Smooth in permanent teeth. Scalloped in deciduous teeth. Dentin is separated from cementum by a zone known as the intermediate cementum layer. This layer is predominantly seen in apical two-thirds of roots of molars & premolars. 22
  23. 23. 23
  24. 24. CEMENTOENAMEL JUNCTIONCEMENTOENAMEL JUNCTION In 60% of the teeth, cementum overlaps the cervical end of enamel for a short distance. In 30% of all teeth, cementum meets the cervical end of enamel in a relatively sharp line. In 10% of the teeth, enamel & cementum do not meet. 24
  25. 25. RELATION OF CEMENTUM TO ENAMELRELATION OF CEMENTUM TO ENAMEL AT THE CEMENTOENAMEL JUNCTIONAT THE CEMENTOENAMEL JUNCTION 25
  26. 26. CLINICAL CONSIDERATIONSCLINICAL CONSIDERATIONS Cementum is more resistant to resorption than is bone, & it is for this reason that orthodontic tooth movement is made possible. It is because bone is richly vascularized, whereas cementum is avascular. Cementum resorption can occur after trauma or excessive occlusal forces. 26
  27. 27. In most cases of repair, there is a tendency to re-establish the former outline of the root surface by cementum. This is called anatomic repair. However, if only a thin layer of cementum is deposited on the surface of a deep resorption, the root outline is not reconstructed, & a bay like recess remains. In such areas the periodontal space is restored to its normal width by formation of a bony projection, so that a proper functional relationship will result. the outline of the alveolar bone in these cases follows that of the root surface. This is called functional repair. 27
  28. 28. HYPERCEMENTOSISHYPERCEMENTOSIS  Is an abnormal thickening of cementum.  May be diffuse or circumscribed.  May affect all teeth of the dentition, be confined to a single tooth, or even affect only parts of one tooth.  If the overgrowth improves the functional qualities of the cementum, it is termed cementum hypertrophy.  If the overgrowth occurs in non-functional teeth or if it is not correlated with increased function, its termed hyperplasia. 28
  29. 29. Extensive hyperplasia of cementum is occasionally associated with chronic periapical inflammation. Hyperplasia of cementum in non-functioning teeth is characterized by a reduction in the number of Sharpey’s fibers embedded in the root. Spur or prong like extension of cementum is found in teeth that are exposed to great stress. Knob like projections are designated as excementoses. 29
  30. 30. 30
  31. 31. ATTACHED CEMENTICLES ON SURFACEATTACHED CEMENTICLES ON SURFACE OF CEMENTUMOF CEMENTUM 31
  32. 32. THANK YOUTHANK YOU
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