Diese Präsentation wurde erfolgreich gemeldet.
Die SlideShare-Präsentation wird heruntergeladen. ×
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Nächste SlideShare
Cementum
Cementum
Wird geladen in …3
×

Hier ansehen

1 von 93 Anzeige

CEMENTUM

Herunterladen, um offline zu lesen

Cementum forms a functional unit which is designed to maintain tooth support, integrity, and protection.

Minor, non-pathological resorption defects on the root surface are generally reversible and heal by reparative cementum formation.

Irreversible damage may occur when the cementum is exposed to the environment of a pocket or oral cavity.

Cementum forms a functional unit which is designed to maintain tooth support, integrity, and protection.

Minor, non-pathological resorption defects on the root surface are generally reversible and heal by reparative cementum formation.

Irreversible damage may occur when the cementum is exposed to the environment of a pocket or oral cavity.

Anzeige
Anzeige

Weitere Verwandte Inhalte

Ähnlich wie CEMENTUM (20)

Anzeige

Weitere von Dr. B.V.Parvathy (20)

Aktuellste (20)

Anzeige

CEMENTUM

  1. 1. CEMENTUM PRESENTED BY, DR. BEENA VIJAYAN PARVATHY DEPT. OF PERIODONTOLOGY
  2. 2. • INTRODUCTION • DEFINITIONS • CEMENTOGENESIS AND MINERALIZATION • PHYSICAL CHARACTERISTICS • CHEMICAL CHARACTERISTICS • CEMENTUM PROTEINS • CLASSIFICATION • CELLS OF CEMENTUM • FUNCTIONS • AGE CHANGES IN CEMENTUM • CEMENTUM IN PERIODONTAL DISEASE • ANOMALIES IN CEMENTUM • CLINICAL CORRELATION • REFERENCES CONTENTS
  3. 3. • The normal periodontium provides the support necessary to maintain teeth in function. It consists of four principal components: gingiva, periodontal ligament, cementum and alveolar bone. • Cementum was first demonstrated microscopically by Fraenkel and Raschkow (1835) and Retzius (1836), later Bhaskar S N (1991). It was said as hard bone like tissue covering anatomic roots of teeth by Newman et al (2006). • The word Cementum comes from the Latin word “Cement” which means “Quarried stone”. INTRODUCTION
  4. 4. • Thin, calcified tissue of ectodermal origin covering the roots of the teeth in which embedded collagen fibers attach the teeth to alveolus. (GPT, 2004) • Calcified, avascular mesenchymal tissue that forms the outer covering of the anatomic root. (Carranza 11th Edition) • Mineralized connective tissue that covers the roots of the teeth. (Listgarten 1st Edition) DEFINITIONS
  5. 5. • Bone-like mineralized tissue lining the dentin of the root that protects the root and also serves as an attachment surface to anchor the PDL to the tooth. (Diekwisch, 2001) • Mineralized connective tissue, in part not unlike bone, that covers the entire surface of antomical roots of teeth. (Schroeder) • Hard, avascular connective tissue that covers the root of the teeth. (TenCate’s)
  6. 6. CEMENTOGENESISANDMINERALIZATION HERS derived from the inner & outer enamel epithelium induces secretion of enamel protein. Sends inductive signal to ectomesenchymal pulp cells to secrete pre-dentin by differentiating into odontoblasts Breaks occur in HERS Ectomesenchymal cells from the inner portion of the dental follicle come in contact with pre- dentin by differentiating into cementoblasts Cementoblasts lay down CEMENTUM
  7. 7. CEMENTOGENESIS
  8. 8. • Mineralization begins in the depth of precementum. • Fine hydroxyapatite crystals are deposited, first between and then within the collagen fibrils by a process that is identical to the mineralization of bone tissue. • The width of the precementum layer is about 3-5 µm. • The process of establishing the appropriate condition for crystallization & growth of the individual crystals in cementum normally are extremely slow and extend over a period of several months. MINERALIZATION
  9. 9. • The development of cementum has been subdivided into: (Bosshardt and Selvig,1997)  Pre-functional stage(3.5-7.5yrs)  Functional stage  The Pre-functional portion of cementum is formed during root development & is extremely long lasting process.  The Functional development of cementum starts when the tooth is about to reach the occlusal level & is associated with the attachment of root to the surrounding bone & continues throughout the life. During this stage, the adaptive and reparative processes are carried out by the biological responsiveness of cementum.
  10. 10. • The PDL fibers are oriented parallel to the root surface and not attached to fibrous fringe. • Slow increase in thickness and establishment of continuity between collagen fibers of the PDL with fibrous fringes occurs. • This happens only after tooth has erupted into the mouth, when 2/3 of root has formed. • Thickness-10µm. • This forms, Acellular intrinsic fiber cementum. DEVELOPMENT OF PRIMARY (ACELLULAR) CEMENTUM (BERKOWITZ ET AL, 2002)
  11. 11. • Appears in the apical region of the root at the time tooth erupts. • Seen in furcation areas of multirooted teeth also. • Following the loss of continuity of HERS, large basophilic cells in adjacent cells of dental follicle against surface of root dentine differentiates. This form a distinct layer of cementoblasts. • These cementoblasts consists of more cytoplasm and cytoplasmic processes. • Cementoblasts secrete the collagen with ground substance forms the intrinsic fibers of secondary, cellular cementum. • They are oriented parallel to the root surface. DEVELOPMENT OF SECONDARY (CELLULAR) CEMENTUM
  12. 12. • HARDNESS < Dentine. • COLOR: Light yellow with dull surface & lighter than dentine. • THICKNESS: Variable Thinnest at CEJ (20-50µm) Thickest towards APEX (150-200µm) • PERMEABILITY: Cellular cememtum > Acellular cementum. with age. PHYSICALCHARACTERISTICS (BERKOWITZ ET AL, 2002)
  13. 13. DRY WEIGHT BASIS o Organic content & water: 50-55%. o Inorganic content (Calcium & phosphate as hydroxyapetite crystals): 45-50%. BY VOLUME o Inorganic: 45%, Organic: 35%, Water: 20% ORGANIC CONTENT o Collagen fibers embedded in an interfibrillar ground substance consisting of glycoproteins.  Types of collagen : Type I (90%), Type III (5%), Type V, Type IX, Type XIV CHEMICALCHARACTERISTICS (BERKOWITZ ET AL,2002) & (BOSSHARDT AND SELVIG,1997)
  14. 14. 2 main sources of collagen fibers:- 1.Sharpeys fibers (Extrinsic) are the embedded portion of the principal fibers of periodontal ligament and formed by fibroblasts. 2.Fibers that belong to the cementum matrix (Intrinsic) and produced by cementoblast. o Non collagenous proteins. o Cementum proteins.
  15. 15. INTERSPERCED BETWEEN COLLAGEN FIBRILS Glycosaminoglycans: • Major GAGs: hyaluronic acid & keratan sulfate. • Play major regulatory roles during cementum mineralization and are associated with initial phase of cementum formation. Dermatan sulphate: Chondroitin 4-sulphate: CEMENTUMPROTEINS
  16. 16. NON COLLAGENOUS PROTEINS Enzyme activity adjacent to CIFC is than AEFC and thickness correlates (Groeneveld et al, 1995). Alkaline phosphatase (Beertsen and Events, 1990): • Play important role in skeletal mineralization. • Regulate tissue turnover & cell proliferation, differentiation, maturation. • Major function is hydrolysis of inorganic pyrophosphate, a potent inhibitor of hydroxyapitite formation. • Plays key biological role in the mineralization of bone & cementum.
  17. 17. Bone sialoprotein & Osteopontin: • Play a major role in filling spaces created during collagen assembly. • Regulators of hydroxyapitite crystal nucleation and growth. • Role in differentiation of cementoblast progenitor cells to cementoblasts. Osteonectin (Gage et al; 1989): • Mainly secreted by osteoblasts. • Important for mineralization process. • Found in the PDL.
  18. 18. Osteocalcin (Mariotti, 1993): • Also know as bone Gla protein (B.G.P) as it contains γ- carboxyglutamic acid (Gal) residues. • Mainly secreted by osteoblasts, regulate mineralization process, prevent hypercalcification of the cementum surface. Fibronectin(Lukinmaa et al, 1991): • Binds cells to components of extracellular matrix. • Found in attachment site of PDL but not in cementum layer. Vitronectin:
  19. 19. SPECIFIC PROTEINS Insulin like growth factor-I: • Ability of cell migration, adhesion, mitogenic activity & differentiation, essential for periodontal regeneration. • Cementum has the potential to regulate the metabolism & turn over of surrounding tissues because of this growth factor. Cementum Attachment Protein (CAP): • Promotes the attachment of gingival fibroblasts, endothelial cells & smooth muscle cells.
  20. 20. • Binds selectively to periodontal ligament cells and supports periodontal ligament cell attachment to root surfaces. Cementum Protein-I: • Synthesized by Hertwig’s epithelial root sheath cells. • Play a role during the mineralization process. • Present throughout the entire cementum surface • Associated with the regulation of sialoprotein expression in cementoblasts. Enamel- Associated Proteins In Cementum: • Synthesized by Hertwig’s epithelial root sheath cells.
  21. 21. • Results in the formation of a cellular- like tissue or bone with the characteristics of cellular intrinsic fiber cementum. • Functions: promotion of cell proliferation, differentiation & up regulation of extracellular matrix production. • Involved in root formation. INORGANIC CONTENT • Calcium & phosphate in the form of hydroxyapitite(Ca10(Po4)6(OH)2). • Trace elements like Copper, Fluorine, Iron, Lead, Potassium, Silica, Sodium and Zinc in varying amounts. • Cementum has the highest fluoride content.
  22. 22. BASED ON LOCATION Radicular Cementum Coronal Cementum Found on the root surface Forms on the enamel covering the crown CLASSIFICATION
  23. 23. ACELLULAR CEMENTUM • Present on the cervical third or half of root. • Does not contain cells. • Formed before the tooth reaches the occlusal plane. • More calcified • Sharpey’s fibers are main component which are inserted at approximately right angles onto the root surface. • Rate of development is faster • Incremental lines are wide apart CELLULAR CEMENTUM • Present mainly on apical third of root. • Contain cells called cementocytes • Formed after the tooth reaches the occlusal plane. • Less calcified • Sharpey’s fibers occupy smaller portion & occupy other fibers that are arranged parallel to the root surface. • Slow • Closer BASED ON PRESENCE/ABSENCE OF CELLS (BERKOWITZ ET AL, 2002)
  24. 24. EXTRINSIC FIBRES • Derived from PDL. • Formed by fibroblast. • Run in same direction of the PDL principal fibers i.e. perpendicular or oblique to the root surface INTRINSIC FIBRES • Derived from cementum. • Formed by cementoblast. • Run parallel to the root surface and at right angles to the extrinsic fibers. BASED ON ORIGIN OF MATRIX FIBRES The area where both extrinsic and intrinsic fibers is called mixed fiber cementum.
  25. 25. FIBRILLAR CEMENTUM: Cementum with a matrix that contains well-defined fibrils of type I collagen. AFIBRILLAR CEMENTUM: Cementum that has a matrix devoid of detectable type I collagen fibrils. Instead, the matrix tends to have a fine, granular consistency. BASED ON PRESENCE OF COLLAGEN FIBRES
  26. 26. The classification system devised by Owens and others in the 1970s was accepted the most at that time , and was summarized by Schroeder & Page.
  27. 27. Acellular afibrillar cementum (AAC) Acellular extrinsic fiber cementum (AEC) Cellular mixed stratified cementum (CMSC) Cellular intrinsic fiber cementum (CIFC) Hyaline layer of Hopewell-Smith (intermediate cementum) SCHROEDERANDPAGECLASSIFICATION(1986)
  28. 28. 1. ACELLULAR AFIBRILLAR CEMENTUM (AAC): • Consists of mineralized matrix. • Contains neither cells nor extrinsic/intrinsic fibers. • No function in tooth attachment. • Formed by cementoblasts. • Found in coronal cementum ie; cervical margin of the tooth. • Less homogenous. • Thickness : 1-15 μm. • The enamel at cervical area not covered by reduced dental epithelium before tooth eruption. The connective tissue of the dental sac lay down cementum on the exposed enamel.
  29. 29. • Confined to coronal half of the root . • Its formation commences shortly after crown formation is completed. • Formed by fibroblast & cementoblasts. • Thickness- 30-230 μm. • Composed of densely packed bundles of sharpey’s fibers & lack cells. • Only type of cementum seen in single rooted teeth. • Has the potential to adapt to functionally dictated alterations such as mesial tooth drift. 2.ACELLULAR EXTRINSIC FIBER CEMENTUM(AEC)
  30. 30. 3. CELLULAR MIXED STRATIFIED CEMENTUM(CMSC) • Composed of extrinsic (sharpey’s fibers) & intrinsic fibers. • Contain cells. • Co- product of fibroblasts & cementoblasts. • Appears primarily in apical 3rd of roots, apices & furcation areas. • Thickness- 100-1000 μm. • With light microscope its easily identified because: o It includes cementocytes within lacunae, with processes in canaliculi directed towards PDL. o Its laminated structure. o The presence of cementoid on its surface.
  31. 31. CELLULAR MIXED STRATIFIED CEMENTUM(CMSC)
  32. 32. • Contains cells & intrinsic collagen fibers. • Formed by cementoblasts. • Fills the resorption lacunae. • Very minor role in attachment. • Seen in middle to apical 3rd & inter radicular cementum. 4. CELLULAR INTRINSIC FIBER CEMENTUM(CIFC)
  33. 33. • Sometimes dentine is separated from cementum by a zone known as the intermediate cementum layer. • It does not resemble either dentine or cementum. • Usually it is present in the apical two thirds of the roots of molars and premolars, rarely seen in incisors or deciduous teeth. • It is believed that this layer represents areas where cells of Hertwig’s epithelial root sheath become trapped in a rapidly deposited dentine or cementum matrix. • Sometimes the intermediate cementum is found as a continous layer & at times found only in isolated areas. • Thickness-10µm. 5. HYALINE LAYER OF HOPEWELL-SMITH (INTERMEDIATE CEMENTUM)
  34. 34. CEMENTOBLAST S CEMENTOCYTES CEMENTOCLASTS Originate from the ectomesenchymal cells in the dental follicle surrounding the developing tooth. Spider like cells incorporated into cellular cementum. Resemble osteoclasts. Synthesize collagen & protein polysaccharides. Lie in lacunae. Mononuclear cells, found on the surface of cementum Have numerous mitochondria, a well- defined Golgi apparatus & large amounts of Cytoplasmic vol & density of cytoplasmic organelles is reduced when compared to cementoblasts. Role- Resorption & Repair. CELLSOF CEMENTUM
  35. 35. CEMENTOBLASTS CEMENTOCYTES CEMENTOCLASTS
  36. 36. • Cementum overlaps enamel: 60% • Cementum just meets enamel: 30% • Small gap between cementum and enamel: 10% CEMENTOENAMEL JUNCTION (NEWMAN ET AL, 2006)
  37. 37. • The cementum is attached to the dentin firmly. • CDJ is scalloped in deciduous teeth and is smooth in permanent teeth. • Sometimes cementum and dentin is separated by an intermediate layer. • Width appears to be stable even as age increases. • About 2-3 μm wide. CEMENTODENTINAL JUNCTION
  38. 38. • Along the external surface of predentin, the precementoblasts differentiate into cementoblasts. • Tiny cytoplasmic processes from initial collagen fibrils of precementum attaches to the predentin. • Intimate interdigitation of two different fibril populations forms dentinocemental junction which gets mineralized later. DEVELOPMENT OF DENTINOCEMENTAL JUNCTION
  39. 39. • Referred to as “ Incremental lines of Salter”. • Represent rhythmic periodic deposition of cementum. • Appear as dark lines running parallel to root surface . • Seen in both acellular & cellular cementum but more prominent in acellular cementum. • Highly mineralized areas with less collagen & ground substance. INCREMENTAL LINES OF CEMENTUM
  40. 40. • Extensive variation in surface topography of cementum can be observed with scanning electron microscope (SEM). • Resting cemental surfaces, where mineralization is more or less complete, exhibit low rounded projections known as cemental mounts. • Cemental surfaces with actively mineralizing fronts have numerous small openings. • Represent unmineralized cores of openings. NORMAL FEATURES OF CEMENTUM
  41. 41. • Anchorage. • Functional adaptation. • Repair. FUNCTIONS
  42. 42. • Provide ancourage of the tooth in its alveolus: accompanied collagen fiber bundles of the periodontal ligament, are embedded in the cementum during cementogenesis. • EXAMPLE- in hypophosphatasia, loosening and premature loss of anterior deciduous teeth occurs. The exfoliated teeth are characterized by an almost total absence of cementum. ANCHORAGE
  43. 43. • Continuous deposition of cementum is of functional importance. • Cementum is not resorbed under normal conditions. • As the most superficial layer of cementum ages, a new layer is deposited that keeps the attachment apparatus intact. • It maintains occlusal relationships, As tooth erupts, to compensate the lost substance, deposition of new cementum occurs at apical root area. FUNCTIONAL ADAPTATION
  44. 44. • Serves as a major reparative tissue for root surfaces. • Damage to roots such as fractures and resorptions can be repaired by the deposition of new cementum • Generally occur when the degree of destruction is low. • The root outline is re-establised as it was before cemental resorption. • To maintain the width of periodontal ligament, the adjacent alveolar bone grows and takes the shape of the defect following the root surface. This is done to improve the function of tooth. REPAIR
  45. 45. Other functions include: • Serves periodontal ligament space. • Walling in filled canals. • Sealing of necrotic pulps. • Protection of the subjacent dentinal tubules.
  46. 46. Healing /sealing of canal by the cementum
  47. 47. • Resorption is carried out by multinuclear odontoclasts & may continue into the root dentine. • Cementum is less susceptible to resorption than bone. • Permanent teeth do not undergo physiologic resorption as do primary teeth. • Appears microscopically as bay like concavities in the root surface. • It is not necessarily continuous & may alternate with periods of repair & deposition of new cementum. • The newly formed cementum is demarcated from the root by a deep staining irregular line, termed as reversal line. RESORTION OF CEMENTUM
  48. 48. Local conditions  Trauma from occlusion  Orthodontic movement  Cysts & Tumours  Pressure from malaligned erupting teeth.  Periapical & Periodontal disease Systemic conditions  Ca deficiency.  Hypothyroidism.  Paget’s disease. Idiopathic conditions
  49. 49. COMPARISON OF BONE AND CEMENTUM Cementum is similar to bone in its: (Saygin et al, 2000) o Organic fibrous frame work o Ground substance o Crystal type o Developmental process o Reorganizational capabilities o Chemical composition Diseases that affect bone, often alter cementum’s properties as well. Eg:- Paget’s diseases results in hypercementosis, hypophosphatasis results in no cementum formation.
  50. 50. BONE CEMENTUM 70% made of inorganic salts. 46% made of inorganic salts. Type I collagen found in organic matrix. Type I and II collagen found in organic matrix. Not permiable. Relatively permiable. Undergoes remodelling. Does not undergo remodelling. Vascular Avascular Have Haversian canals. Lack Haversian canals. Innervated Not innervated Comparatively faster resorption. Less readily resorbed.
  51. 51. • Smooth surface becomes irregular. • Continuous deposition of cementum occurs with age in the apical area. • Deposited at linear rate(Azaz et al, 1974). • Cementum resorption active for a period of time and then stops for cementum deposition creating - reversal lines. • Resorption of root dentin occurs with aging which is covered by Cemental repair. AGECHANGESIN CEMENTUM (BOSSHARDT AND SELVIG, 1997)
  52. 52. CEMENTUMIN PERIODONTALDISEASE
  53. 53. • Loss of collagen fiber insertion. • Contamination by bacteria and or endotoxins. • Alterations in mineral density and composition. • Lack of chemotactic stimuli for periodontal regeneration. • Apical migration of the junctional epithelium. PATHOGENIC CHANGES IN CEMENTUM
  54. 54. • In normal cementum, the collagen fibers are embedded in the cementum. • These fibers are destroyed in pathological pocket wall with the exposure of cementum. • Exposed in cases of gingival recession leading to pocket formation. • Collagen remnants of Sharpey’s fibers in cementum undergo degeneration creating a environment favorable for penetration of bacteria. • The mineral content of exposed cementum increases. EXPOSURE OF CEMENTUM TO THE ENVIORNMENT
  55. 55. • Firm scaling strokes used to remove sub gingival calculus, also remove a small amount of cementum resulting in some notching of root. NECROTIC CEMENTUM: • Cementum exposed by apical migration of junctional epithelium is altered by exposure to sub gingival plaque within the pocket. • May become hyper mineralized, demineralized or necrotic.
  56. 56. • Lopez et al, 1980 it is necessary to remove all the diseased cementum exposed to the pocket to eliminate its potential for inducing inflammation. • Nyman et al, 1986 intentional root cementum removal is not necessary for optimal postoperative healing. • Removal of cementum during root planning process has been questioned due to possible sequelae of root sensitivity. • Also, it is thought that cementum removal is not necessary to remove endotoxin because it is weakly adherent to cementum. (Wilson & Kieser; 1988, Hughes & Smales, 1986, Smart, Wilson, Daves & Kieser, 1990)
  57. 57. PRESENCE OF PATHOLOGIC GRANULES(Carranza and Newman, 1996) • Reported by Bass, 1951. • Areas where collagen degeneration or collagen fibers not been mineralized initially. • Granules extend 3-12µm into the surface of cementum. • Morphological Pattern:  Grape like structure  Long chain aggregated  Small isolated vacuoles  Very long fissure like area (Garrett, 1975)
  58. 58. According to Gottlieb (1946) the persistence of precementum layer with its cementoblasts was essential for the integrity of the tooth. Hitchin(1973,1975) has reported that patients with Epidermolysis bullosa and Cleido-cranial dysostosis showed changes in cementum. The changes he found appeared to be in accord with Gottlieb’s (1946) views on cementum formation but altered by hypersensitivity to mechanical stress in one instance and a disturbance of bone resorption in the other.
  59. 59. • Detoxify and demineralize the root surface (citric acid) • Selective removal of hydroxyapatite and exposure of the collagenous matrix of the root surface (EDTA) • Inhibition of collagenolytic activity (tetracycline HCL) • Enhances cellular responses (migration and attachment) • Prevents epithelial down-growth • Improves retention of different biomolecules to exposed collagen • Expresses a cementoblast phenotype for colonizing cells. CHEMICAL ROOT SURFACE TREATMENT – EFFECTS ON CEMENTUM
  60. 60. 1.CONCRESENCE(Shafer et al,2006): • Form of fusion which occurs after the root formation has been completed. • Here the teeth are united by cementum only, as a result of traumatic injury or crowding of teeth with resumption of the interdental bone so that the two roots are in approximate contact and become fused by deposition of cementum between them. • Concresence can occur before or after teeth have erupted and usually involves two teeth. ANOMALIESOFCEMENTUM
  61. 61. 2. CEMENTICLES: • Globular masses of cellular cementum less than 0.05mm in diameter which form within the periodontal ligament. • May lie free within the periodontal ligament(free cementicles) or become fused to the radicular cemental surface(sessile or attached cementicles). • Originate from degenerating cells or epithelial cell rests in the periodontal ligament.
  62. 62. 3.HYPERCEMENTOSIS (Cemental hyperplasia) (Neville et al, 2002): • Abnormal thickening of cementum. • It is largely an age related phenomenon • May affect all teeth of the dentition (Generalized), or be confined to a single tooth or even effect only parts of one teeth (Localized). • Localized hypercementosis may sometimes be observed in areas in which enamel drops have developed on the dentin. • Such knob like projections are designated as excementosis. • The thickening of cementum is often observed on teeth that are not in function.
  63. 63. • If the overgrowth improves the functional qualities of the cementum, it is termed as cementum hypertrophy. • If the overgrowth occurs in non-functional teeth or if it is not correlated with increased function, it is termed cemental hyperplasia.
  64. 64. Appearance: • Occurs as a generalised thickening of cementum, with nodular enlargement of the apical third of the root • It also appears in the form of spike like excrescences (cemental spikes) created by either the coalescence of cementicles that adhere to the root or the calcification of the periodontal fibres at the site of insertion into the cementum. • It is usually associated with situations like - teeth without antagonist - teeth with pulpal and periapical infections
  65. 65. • Hypercementosis of entire dentition may be seen in patients with Paget's disease. • Other systemic disturbances include acromegaly, calcinosis, thyroid goiter, arthritis etc. Treatment: • Hypercementosis itself does not need treatment. • It could pose a problem if an affected tooth requires extraction. • In multirooted tooth, sectioning of tooth may be required before extraction.
  66. 66. 4.HYPOPLASIA (Cemental aplasia): • Absence or paucity of cellular cementum. 5. HYPOPHOSPHATASIA: • Due to an inborn error of metabolism. • The basic disorder is a deficiency of enzyme alkaline phosphatase in serum or tissues. • This is characterised by loosening and premature exfoliation of deciduous teeth mainly anteriors. • Exfoliated teeth microscopically show complete absence of cementum or isolated areas of abnormally formed cementum.
  67. 67. 6.ANKYLOSIS(Shafer et al, 2006): • Fusion of cementum and alveolar bone with obliteration of periodontal ligament. • Results in resorption of root and its replacement by bone tissue. • It occurs due to:- 1) Cemental resorption 2) Chronic periapical inflammation 3) Tooth replantation 4) Occlusal trauma 5)Around embedded teeth
  68. 68. Clinically: 1. Lack of physiologic mobility which is diagnostic sign of ankylotic resorption. 2. As the periodontal ligament is replaced with bone in ankylosis, proprioception is lost because pressure receptors in periodontal ligament are deleted or not function correctly. 3. Teeth have special metallic percussion sound. 4. If the process continues teeth will be in infraocclusion.
  69. 69. Radiographically: • Resorption lacunae are filled with bone. • Periodontal ligament space is missing. Treatment: • No predictable treatment can be suggested. • Treatment modalities range from a conservative approach, such as restorative intervention to surgical extraction of affected tooth.
  70. 70. 7. CEMENTAL TEARS: • Detachment of a fragment of cementum from the root surface. • Separation of cementum, may be complete with displacement of a fragment into the periodontal ligament or it may be incomplete with cementum fragment partially attached to the roots. • Detached cementum, may be reunited to the root surface by new cementum or may be completely resorbed or may undergo partial resorption followed by addition of new
  71. 71. 8. ENAMEL PEARLS: • If some HERS cells remain attached to forming root surface, they can produce focal deposits of enamel like structures called ENAMEL PEARLS. Clinical significance • They are plaque retentive structures. • Promote periodontal disease. • They look similar to calculus, but cannot be scaled off. • Only grinding will help in elimination.
  72. 72. 9.Cementopathia: In 1923, Gottlieb reported a patient with fatal case of influenza and disease called Diffuse atrophy of bone. • Characterized by loss of collagen fibers in PDL and their replacement by loose connective tissue and extensive bone resorption resulting in the widened PDL space • Gottlieb attributed this condition to inhibition of continuous cementum formation which he considered essential for maintenance of PDL fibers. • He then termed the disease as CEMENTOPATHIA.
  73. 73. 10.CALCULOCEMENTUM(Newman et al): Calculus embedded deeply in cementum may appear morphologically similar to cementum. 11. ROOT CARIES: 12.ABRASION:
  74. 74. 1.BENIGN CEMENTOBLASTOMA(True Cementoma): • A true neoplasm of functional cementoblasts which form a large mass of cementum or cementum like tissue on the root. • No sex predilections and frequently seen under age of 25yrs. • Mandibular 1st permanent molar, most affected. • Other includes, Mandibular 2nd and 3rd molar, bicuspids, maxillary bicuspids and 1st,2nd and 3rd molars. • Slow growing, asymptomatic and may cause cortical bone expansion. • Radiographically, well circumscribed dense radioopaque mass surrounded by thin, uniform radiolucent line attached NEOPLASMS OF CEMENTUM (SHAFER ET AL, 1997)
  75. 75. • Histologically, composed of sheets of cementum with reversal lines scattered throughout. • Treatment by extraction of tooth, rare recurrence. 2.PERIAPICAL CEMENTAL DYSPLASIA: • Also called as, Cementoma; Periapical Osteofibroma; Osteofibrosis; Cementifying fibroma; Localized fibro- osteoma; Cementoblastoma; Periapical fibrous Dysplasia. • Common in 20yrs. • Occurs in PDL around apex of the tooth in mandibular incisors. • Asymptomatic, when near mental nerve causes pain, paresthesia and even anesthesia.
  76. 76. 3.CENTRAL CEMENTIFYING FIBROMA: • Neoplasm of bone. • Histologicaly contains collagen fibres interspersed by large numbers of active, proliferating fibroblasts or cementoblasts. 4.GIGANTIFORM CEMENTUM(Familial Multiple Cementoma): • Contains highly calcified acellular cementum. 5.FOCAL CEMETOOSSEOUS DYSPLASIA: • Histologically, trabeculae of woven bone and cementum like material are interspersed throughout the fibrous framework.
  77. 77. Age estimation from incremental lines of cementum: • (Kagerer and Grupe) suggested age estimation from acellular cementum. • Authors claimed an accuracy of within 2 or 3 yrs of chronological age. • Cementocytes a fruitful source of DNA. • Cementum resists DNA degradation in comparision to other tissues with respect to the intra and inter-individual variation of histological and anatomical structures. APPLICATION IN FORENSIC ODONTOLOGY
  78. 78. • The importance of cervical third of the cementum is that it contains acellular extrinsic fiber cementum and its regeneration is considered to be the gold standard for periodontal regeneration. • Such tissue regeneration is achieved by biomimicking the physical and mechanical properties of the tissue, which serves as a scaffold in nature. • Application of Insulin-like growth factor. • Application of BMP-2. • Direct gene transfer of platelet-derived growth factor-B stimulates the regeneration of cementum. CEMENTUM REGENERATION
  79. 79. • In periodontal pockets, pathologically exposed cementum, undergoes alterations, this interferes with healing. • Root planning leads to hypomineralised cementum. • Scaling produces are painles, if cementum is removed, this leads to dentin is exposure causing root hypersensitivity. • Precementum acts as the natural barrier to excessive apical migration of junctional epithelium. •Subsurface alteration occurs on gingival inflammation. CLINICAL CORRELATION
  80. 80. • Cementum forms a functional unit which is designed to maintain tooth support, integrity, and protection. • Minor, non-pathological resorption defects on the root surface are generally reversible and heal by reparative cementum formation. • Irreversible damage may occur when the cementum is exposed to the environment of a pocket or oral cavity. CONCLUSION
  81. 81. 1. Carranza’s clinical periodontology 10th Edition. 2. Orban’s oral histology and embryology. 12th Edition. 3. Thomas M. Hassell;Tissues and Cells of the Periodontium; Periodontology 2000, Vol. 3, 1993, 9–38. 4. Dieterd. Bosshardt & Knut A. Selvig; Dental cementum: the dynamic tissue covering of the root; Periodontology 2000. Vol.13, 1997, 41-75. 5. M I Cho et al;Development and general structure of the periodontium: Periodontology 2000, Vol. 24, 2000, 9–27. 6. Higinio Azrate et al;Cementum proteins: Role in cementogenesis, biomineralization, periodontium formation and regeneration. Periodontology 2000, Vol.67, 2015. REFERENCES
  82. 82. 6. Hussam Mansour, Oliver Krebs, Jan Peter Sperhake, Christa Augustin, Till Koehne, Michael Amling, Klaus Püschel; Cementum as a source of DNA in challenging forensic cases; Journal of Forensic and Legal Medicine. 7. Shafer’s Textbook of Oral Pathology 8th Edition. 8. Oral ad Maxillofacial Pathology (Neville) 3rd Edition.

×