Cementum

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Cementum

  1. 1. CEMENTUM Submitted by:- Madhuri arora BDS intern 1
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  3. 3. CementumDerived from dental follicleHard, Calcified, avascular mesenchymal tissueYellowish in colorLighter and less harder than dentinPermeableThe thickness of cementum varies considerably and the cervical third may be only 16-60 µm thickIn contrast, the apical third can be 200µm or even thicker. 3
  4. 4. CompositionOrganic:- Inorganic:- 50-55%  40-45% Type 1 Collagen  Hydroxyapetite Fibers and type III  Calcium Collagen fibres  Phosphate Protein  Traces of magnesium Polysaccharides  Fluorides  Water 4
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  6. 6. Matrix proteinspredominantly of Type I Collagen & Glycosaminoglycans (Chondroitin sulphate mainly)Bone matrix proteins are secreted by cementoblasts & deposited in cellular cementumOsteopontin is concentrated in cement lines (resting Salter lines).It mediates cell attachment & cohesion of matrix molecules at incremental linesBone sialoprotien and osteopontin are believed to play major in differentiation of cementoblasts progenital cells to cementoblastsCementum also contains Growth factors. 6
  7. 7. Collagen fiberstwo sourcesExtrinsic fibers Intrinsic fibersincorporation of the Produced by periodontal ligament cementoblast fibers. Run parallel to rootAlso called as surface sharpey’s fibersRun in same direction of principal fibers 7
  8. 8. According to presence or absenceof cellsAcellular cementumCellular cementum 8
  9. 9. CLASSIFICATION OFCEMENTUM 9
  10. 10. Acellular cementum Cellular cementum First formed cementum  Formed after acellular cementum Most of it is formed before the tooth  Most of it is formed formed after reaches occlusal plane tooth reaches occlusal surface Covers approx the cervical third or  Covers the apical third of root half of the root  Contain cementocytes No cells  Less calcified More calcified  Small portion Sharpey’s fibers make up most of the structures  May be completely or partially Completely calcified calcified 10
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  12. 12. B ACellular cementum (B) overlying acellular cementum 12
  13. 13. According to content of fibrilsFibrillar cementum AfibrillarcementumContains well it lacks dense array defined densely of collagen fibrils packed collagen although rare fibrils in it’s matrix. isolated fibrils will be present. 13
  14. 14. According to Schroeder et al1. Acellular afibrillar cementum Neither cells nor fibers Mineralized ground substance It is a product of cementoblasts Found as coronal cementum Thickness of 1-5 µm 14
  15. 15. 2. Acellular extrinsic fibrecementum Densely packed bundles of sharpey’s fibers Lacks cells Product of fibroblast and cementoblast Found in cervical third Thickness is between 30-230 µm 15
  16. 16. 3. Cellular mixed stratifiedcementum Extrinsic and intrinsic fibers May contains cells Co-product of cementoblast and fibroblast Apical third and furcation areas 100-1000 µm 16
  17. 17. CMSC 17
  18. 18. 4. Cellular intrinsic fibercementum Contains cells no extrinsic collagen fibers. Formed by cementoblast It fills resorption lacunae 18
  19. 19. CIFC 19
  20. 20. 5. Intermediate cementum Hyaline layer of Hopewell Smith Poorly defined zone near the cemento-dentinal junction of certain teeth that appears to contain cellular remnants of Hertwig’s sheath embedded in calcified ground substance. 20
  21. 21. Intermediate cementum(layer of calcified tissueembedded in betweendentin and cementum atthe periphery of dentalroots) 21
  22. 22. •Incremental lines of Salter• These lines represent the rest periods in cementum formation and are more mineralized than the adjacent cementum.• Both cellular and acellular are arranged in lamillae seperated by incremental lines• These lines are parallel to the long axis of the root •22
  23. 23. Cemento-enamel junction 23
  24. 24. Pattern 1- Where the cementum overlaps the enamel for a short distancePattern 2- Where the cementum and the enamel meet at the butt joint.Pattern 3- Where the cementum and enamel fail to meet and the dentine is exposed, the patient may experience hypersensitivity. 24
  25. 25. Functions of cementumMedium of attachment of collagen fibers that bind to alveolar boneContinue deposition helps to keep attachment apparatus intactHelps in repair of any resorption 25
  26. 26. AGE CHANGES IN CEMENTUM the width of cementum increases with ageAverage thickness of 95 µm at age of 20 and 215 µm at age of 60 have been reportedThe increase in width is greater in apical and furcation areasPermeability of cementum decreases with age. 26
  27. 27. HYPERCEMENTOSISRefers to non-neoplastic deposition of excessive cementum that is continuous with the normal radicular cementumMay be localized to one tooth or affect entire dentitionOccurs as generalized thickening of cementum, with nodular enlargement of apical third of root. 27
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  29. 29. EtiologySpike like type of hypercementosis Generally results from excessive tension from ortho appliances or occlusal forces.Generalized type occurs in a variety of circumstances.In teeth, without antagonist, hypercementosis as an effort to keep pace with excessive tooth eruption.Also occurs in teeth subject to low grade peri-apical irritation arising from pulp disease. 29
  30. 30. Factors associated with hypercementosiscan be classified as:LOCAL SYSTEMIC FACTORS: FACTORS:Abnormal occlusal Acromegaly and trauma, pituitary gigantism.Unopposed teeth Paget’s disease (e.g. impacted, Thyroid goitre embedded, without antagonist)Adjacent inflammation. 30
  31. 31. Of these factors, Paget’s disease of bone has received the most attention.Numerous authors have reported significant hypercementosis in patients with Paget’s disease, and this disorder should be considered whenever generalized hypercementosis is discovered in patients with appropriate age. 31
  32. 32. Radiographically,affected teeth demonstrate a thickening or blunting of root, but the exact amount of increased cementum is difficult to ascertain because cementum and dentin demonstrate similar radio-densities.The enlarged root is surrounded by radiolucent ligament space and adjacent intact lamina dura. Premolar teeth are most commonly affected. 32
  33. 33. Histologically, the periphery of root exhibits deposition of an excessive amount of cementum over the original layer of primary cementum.The excessive cementum maybe hypocellular or exhibit areas of cellular cementum that resemble bone (osteocementum)On routine light microcopy, distinction between cementum and dentin is difficult, but the use of polarized light clearly separates the two different layers. 33
  34. 34. Hypercementosis itself does not require treatmentIt could cause problem if the affected tooth requires extractionIn multirooted tooth sectioning of tooth may be required before extraction 34
  35. 35. CementiclesGlobular masses of acellular cementumgenerally less than 0.5mm in diameter which form with in periodontal ligamentexhibit concentric appositional layers of afibrillar and/or fibrillar cementum 35
  36. 36. Types Free – with in PDL space Attached- fused to cellular cementum Interstitial(totally incorporated in the cementum)It has been postulated that cementicles originate from foci of degenerating cell or epithelial rests in periodontal ligament.not of clinical significance unless they become exposed to oral environment where they may act as sites for plaque retention. 36
  37. 37. CementomaBenign tumors of cementum 37
  38. 38. Cementum Hypertrophy1- Cemental Hypertrophy:If overgrowth of cementum improves the functional qualities of the cementum it is termed as cementum hypertrophy. 38
  39. 39. Cementum hyperplasiaIfthe overgrowth occurs in nonfunctional teeth or it is not correlated with increased function it is termed as Hyperplasia. 39
  40. 40. Cementum Resorption permanent teeth do not undergo physiological resorption as do primary teethBut cementum is subjectede to resorptive changes that may be of microscopic proportion or sufficiently extensive to produce a radiographically detectable alteration in tooth contour 40
  41. 41. Local factors Systemic factors TFO  Calcium deficiency Ortho movement  Hypothyroidism Pressure from mal-aligned  Hereditary fibrous errupting tooth osteodystrophy Cyst, tumors  Paget’s disease Teeth without functional antagonist Periapical disease Cause Resorption 41
  42. 42. Cementum resorption appears microscopically as baylike concavities in the root surfaceMultinucleated giant cells and large mononuclear macrophage3s ar5e generally found adjacent to cementum undergoing active resorption 42
  43. 43. CEMENTAL REPAIR Cementum resorption is not necessarily continous After resorption has ceased, the damage is usually repaired, either by formation of acellular or cellular cementum or by alternate formation of both. The newly formede cementum is demarcated from the root by a deeply staining irregular line termed as reversal line In most cases of repair there is a tendency to re- establish the former outline of the root surface. This is called anatomic repair. 43
  44. 44. However, if only a thin layer of cementum is deposited on surface of deep resorption, the root outline is not reconstructed and a bay like recess remains.In such cases, some time the periodontal space is restored to it’s normal width by formation of bony projections so that proper functional relationship will result.The outline of the alveolar bone in these cases follows that of the root surface. In contrast to anatomic repair, this change is called functional repair. 44
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  46. 46. Ankylosis:Fusion of cementum and alveolar bone with obliteration of the periodontal ligament is termed as ankylosisAnkylosis occurs in teeth with cemental resorption which suggests it may represent a form of abnormal repairOther causes of ankylosis include tooth reimplantation,occlusal trauma,after chronic periapical inflammation and around embedded teeth 46
  47. 47. Ankylosis results in resorption of the root and its gradual replacement by bone tissue.for this reason reimplanted teeth that ankylose will loose their roots after 4 to 5 years and will be exfoliated 47
  48. 48. Clinical features of ankylosed teethThey lack the physiological mobility of normal teeth(this is one of the diagnostic signs for ankylotic resorption)Teeth have special mettalic percussion soundTeeth may be in infraocclusion 48
  49. 49. Changes in ankylosed teethAs the periodontal ligament is replaced with bone in ankylosed teeth proprioception is lost coz pressure receptors in the periodontal ligamentb are deleted or do not function correctlyPhysiological drifting and eruption of teeth can no longer occur and thus the ability of the teeth and peridontium to adapt to altered force levels or directions of force is greatly reduced 49
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  51. 51. oEXPOSURE OF CEMENTUM TOORAL ENVIRONMENTo Cementum becomes exposed to oral environment in cases of gingival recession and as a result of loss of attachment in pocket formationo This may lead to cemental invasion by bacteriao Cementum caries can also develop o51
  52. 52. THANK YOU 52
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  54. 54. CONCLUSIONCementum is probably the least understood of all dental tissues.But this does not lessen it’s role in the periodontal attachment apparatus.With the development of newer concepts of regenerative cementogenesis and role of cementum in implants, the need for us to better understand this basic tissue should be understood and implemented. 54
  55. 55. References Caranza’s clinical periodontology Orban’s dental anatomy and histology Bath, M., Balogh, M. & Fehrenbach, M. J. (1997) Dental Embryology, Histology, and Anatomy, 1st ed., W.B Saunders, Pennsylvania. Bath, M., Balogh, M. & Fehrenbach, M. J. (2006) Dental Embryology, Histology, and Anatomy, 2nd ed., W.B Saunders, Pennsylvania. Oral antomy, histology and embryology by berkovitz, G.R. Holand and Moxham Shafer’s oral pathology, Internet sources 55

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