Cementum is the mineralized tissue covering the roots of teeth. It is less calcified and harder than dentin. Cementum is formed by cementoblasts and is composed of collagen fibers embedded in a hydroxyapatite matrix. Cementum provides anchorage for periodontal ligament fibers and continues to be deposited throughout life, increasing the thickness of roots. The cementoenamel junction marks the boundary between cementum and enamel and can be overlapped, edge-to-edge, or with cementum failing to meet enamel. Cementum functions to anchor teeth, maintain periodontal ligament width, and repair root fractures. Conditions like hypercementosis, ankylosis, and cementicles can

1. CEMENTUM
DR FAHAD RAZA
POST GRADUATE TRAINEE [PERIODONTOLOGY]

2. INTRODUCTION

3. DEFINATION
It is a mineralized dental tissue covering the anatomic roots of human teeth

4. CHARACTERISTICS
• Calcified structure whose calcification & hardness is less than dentin
• More permeable than dentin
• Light yellow in colour
• Softer and lighter dentin
• Lack luster and is dark therefore differentiated from enamel
• Less readily resorbed than bone

5. LOCATION
 Begins at the cervical portion of the tooth at the cemento enamel junction
& continues to the apex
Radicular cementum ( found on to the root surface )
Coronal cementum ( forms on the enamel covering the crown )

6. THICKNESS
 Coronal half of root 16-60 microns
apical third & furcation areas 150-200 microns
An average thickness of 95 microns {20years} & 215 microns {65 years}
Between 11-70 year thickness increases 3 times
Cemental deposition continues through out the life

7. CHEMICAL COMPOSITION
• Organic content & water - 50-55%
• Inorganic content - 45-55%
ORGANIC CONTENT
• Type I collagen fibres 90%
• Type III collagen fibres 5 %
• Proteins
• Polysaccrides
• Trace elements

8.  INORGANIC CONTENTS
40-50%
Hydroxyapatite
calcium & phosphates
traces of magnesium,fluorine,iron,lead,potassium,silica,sodium & zinc
highest fluoride content

9. SOURCE OF COLLAGEN FIBRES
• IN CEMENTUM
Extrinsic sharpey’s fibre formed by fibroblasts
derived from PDL’s
run in the same direction pdl principal, perpendicular/obligue to the root surface
Intrinsic fibres of cementum matrix formed by cementoblasts
derived from cementum
run parallel to the root surface & at right angles to the extrinsic fibres

10. CEMENTOGENESIS
 It takes place in two phases
Matrix formation
Mineralization
 There are three cell types responsible for the cementogenesis
Cementoblasts
Cementocytes
Fibroblasts
All these cells are derived from the ectomesenchymal cells

11. • Pre functional phase
during root development
time range 3.75 years – 7.75 years
• Fuctional phase
commences when tooth reaches the occulusal plane continues through out the life
• MATRIX FORMATION

12. Enamel organ reached its final stage
Inner & outer enamel epithelium
proliferate to form HERS
Continues mitotic cell activity at
apical termination of HERS
Coronoapical growth of double
layer sheath
Most apical portion seprates the
dental papilla from dental follicle

13. Inner & outer cell layers of HERS are surrounded
by basement membrane
Cells from dental papilla in the radicular pulp
differentiate into odontoblasts & forms radicular
mantle dentin
HERS fragment forms a network
Network enables mesenchymal cells to pass between
cells of root
These mesenchymal cells are cementoblasts

14. Cemntoblast increase in size & develop
all cytoplasmic organelles

15. MINERALIZATION
• Mineralization begins at the depth of pre cementum
• Fine hydroxyapatite crystals are deposited, first between & then within the
collagen fibrils by a process that is identical to the mineralization of bone
tissue
• The width of the precemntum layer is about 3.5 mm
• Linear rate of cementum deposition on single-rooted teeth is about 3
um/year

18. Propose activity
• Adhesion/chemoattractant
Mitogenesis
Differentiation
Mineralization
Molecular factors affected
• Osteopontin, bone sialoprotein, laminin(epithelial
factors), Fibronectin, collage I,II XII, proteoglycans
• Growth harmones,transforming growth factor B, insulin
like growth factor I
• Bone morphogenic protein-3, ameloblastin
• Osteopontin , bone sialoprotein, osteocalcin(controls
mineralization prevents ankyloses) ,proteoglycans,
Collagen type I & XII

19. CLASSIFICATION
• On the basis of
• presence/ absence of cells
• time of formation
• location
• presence/absence of fibres
• Origion of fibres
• Schroeder’s classification

20. • Primary (before tooth eruption) / secondry (after tooth eruption reaches
occulusal plane )
• Coronal & radicular cemntum
• Afibrillar / fibrillary cemntum
• Extrinsic / Intrinsic cementum

22. Schroeder's Classification :
• Acellular Afibrillar Cementum
• Acellular Extrinsic Fiber
• Cellular intrinsic Fiber cementum.
• Cellular mixed stratified cementum
• Intermediate Cementum

23. Acellular
afibrilar
cementum
Acellular
extrinsic fiber
cementum
Cellular mixed
stratified
cementum
Cellular
intrinsic
fiber
cementum
Intermediate
cementum
contents Mineralized ground
substance
Densely packed
bundles of sharpy’s
fibers
-Extrinsic (sharpy’s
f)
-Intrinsic
fibers
- celss
- Intrinsic
fibers
- cells
Poorly defined zone
near the
cementodentinal
junction of certain
teeth.
source cementoblasts Fibroblasts+
cementoblasts
Fibroblasts +
cementoblasts
cementoblasts
site Coronal cementum - cervical
third of
roots
-Apical third of
roots
-Apices
- furcation areas.
Fills resorption
lacunae.
thickness 1-15μm 30-230μm 100-1000μm

24. CEMENTOENAMEL JUNCTION
• the area where enamel and cementum meet at the cervical region of
the tooth.
• Three different relationships among the enamel and cementum:
• 60% to 65% of the cases the cementum overlaps the enamel
• 30% of the cases edge to edge
• 5% to 10% cementum fails to meet enamel resulting in exposed dentin

25. It is the point at which
cementum and enamel meet.
May be of three types.
In some rare cases, a fourth type of
cemento-enamel junction is seen.
In these rare cases, the enamel overlaps the
cementum.

26. FUNCTIONS OF CEMNTUM
• provide anchorage of tooth to alveolus (sharpeys fibers).
• It assists in maintaining occlusal relation by maintaining a balance between
attrition and eruption.
• It serves to maintain the width of PDL space at the apex.
• Cementum repairs root fracture.
• No resorption under masticatory or orthodontic forces so maintains tooth
integrity and fulfils orthodontic requirement.

27. CEMENTAL RESORPTION
Can occur due to physiologic or pathologic
causes
Local causes: Trauma from occlusion,
orthodontic movement, cysts, tumors.
Systemic causes: Calcium deficiency,
Hypothyroidism, Pagets disease.
• MICROSCOPICALLY: Bay like concavities in the root surface

28. AGE CHANGES IN CEMENTUM
CONTINOUS DEPOSITION
• Forms on roots throughout life
• More apically than cervically
• Reduces root surface concavities thicker layer in root surface
grooves and in furcations.
• Variation in tooth position influence pattern of deposition

29. PATHOLOGICAL CONDITIONS
ASSOCIATED WITH CEMENTUM
ANKYLOSIS
• Fusion of cementum and alveolar bone
withobliterated PDL
• Occurs in teeth with cemental resorption
• After periodontal inflammation, tooth
replantation, occlusal trauma.
• Resorption of root and its gradual replacement by
bone
• Lack physiological mobility, metallic percussion
• No proprioception

30. CEMENTICLES
• Abnormal, calcified bodies in the periodontal
ligament
• Form from remnants of HERS
• Usually ovoid or round
• Size ranges from 0.1- 0.4 mm.
• Classified as Free, Attached or Embedded
• Local trauma
• Appear in increasing numbers in the aging
person

31. HYPERCEMENTOSIS
• Hypercementosis is a nonneoplastic
deposition of excessive
• Cementum that is continuous with
the normal radicular cementum.
LOCAL FACTORS
Abnormal occlusal trauma
Adjacent inflammation
Unopposed teeth [e.g.,
impacted, embedded, without
antagonist)

32. SYSTEMIC FACTORS
• Neoplastic and non neoplastic conditions including benign cementoblastoma,
• cementifying fibroma,
• cemental dysplasia
• Acromegaly and pituitary gigantism
• Paget's disease of bone
• Rheumatic fever
• Thyroid goiter

33. CONCRESCENCE
• Fusion of teeth by fusion of cementum
• After root formation has been completed
• Traumatic injury or crowding of teeth with
• resorption of the interdental bone
• Difficulty in extraction

34. REGRESSIVE ALTERATION OF
TEETH
• Abrasion
• Abrasion is the pathologic wearing of tooth substance through some
• abnormal mechanical process.
• Abrasion usually occurs on the exposed root surfaces of teeth, but under
some circumstances, it may be seen elsewhere on tooth
• Abrasion caused by dentrifrice manifests as a v-shaped or wedge shaped
ditch on the root side of cej in teeth with recession.

35. NEOPLASMS ASSOCIATED WITH
CEMENTUM
• CEMENTOBLASTOMA
The benign cementoblastoma is probably a true neoplasm of functional
cementoblasts which form a large mass of cementum or cementum-like tissue on
the tooth root
• CEMENTIFYING FIBROMA
Resemble focal cemento-osseous dysplasia
• The neoplasm is composed of fibrous tissue that contains a variable mixture of
bony trabeculae, cementum like spherules or both.
• origin of these tumors is odontogenic or from periodontal ligament.

36. • PAGETS DISEASE
Paget’s disease is characterized by enhanced resorption of bone.
Etiology: unknown, viral infection, inflammatory cause, autoimmune, connective
tissue and vascular disorder.
• HYPOPHOSPHATASIA
Hypophosphatasia is a rare metabolic bone disease that is characterized by a
deficiency oftissue-nonspecific alkaline phosphatase.
• One of the first presenting signs ofhypophosphatasia may be the premature lossof
the primary teeth presumably caused by alack of cementum on the root surfaces

37. • HYPERPITUITARISM
Gigantism is the childhood version of growth hormone excess and is
characterized by the general symmetrical overgrowth of the body parts.
• Prognathic mandible, frontal bossing, dental malocclusion, andinterdental
spacing are the other features.
• Intraoral radiograph may show hypercementosis of the roots

38. • Acromegaly is characterized by an acquired progressive somatic
disfigurement, mainly involving the face and extremities, but also many other
organs, that are associated with systemic manifestations.
• Dental radiograph may demonstrate large pulp chambers and excessive
deposition of cementum on the roots