This document provides an overview of cementum, including: - Its physical characteristics, composition, classification, and formation process (cementogenesis). - The cells involved in cementum formation and maintenance, including cementoblasts and cementocytes. - Its locations and junctions with other tissues like enamel and dentin. - The functions of cementum in anchoring teeth, adaptation, and repair. - Some developmental anomalies and abnormalities that can affect cementum.

1. Dr anirudh singh chauhan
PG Ist year
department of periodontology

2. CONTENTS
•Introduction
•Physical characteristics
•Composition
•Classification of cementum
•Cementogenesis
•Mineralization
•Cementum associated cells
•Cementoenamel junction
•Cementodentinal junction
•Functions of cementum
•Developmental anomalies of cementum
•Abnormalities of cementum
•Conclusion

3. INTRODUCTION
• Calcified, Avascular mesenchymal tissue that forms the
outer covering of the anatomic root.
Carranza 11th edition.
• First demonstrated in 1835 by FRANKE & RASCHKOV, two
pupils of purkinje.
• Begins at the cervical portion of the tooth at the
cementoenamel junction and continues to the apex.
• Two main types-
- Acellular ( primary)
- Cellular ( secondary)
• Both consist of interfibrillar matrix and collagen fibrils.

4. PHYSICAL
CHARACTERISTICS
• Hardness < Dentin.
• Light yellow in color and lacks luster.
• Lighter in color than dentin, however it may not be
distinguished on basis of color alone.
• Permeability of cellular cementum is greater than that of
acellular cementum. With age, the permeability of
cementum decreases.
• Thinnest at CEMENTOENAMEL JUNCTION (20-50 um)
• Thickest towards the APEX (150-200 um)

5. COMPOSITION
• Dry weight basis:
– 45-50% inorganic substances which consists of calcium and
phosphate in the form of hydroxyapetite crystals.
– 50-55% organic material and water.
• Organic matrix of cementum consists of :
– Type I collagen ( 90%)
– Type III collagen ( 5% )
– Non collagenous proteins.
• By volume:
 45% inorganic
 35% organic
 20% water

6. • Two 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.
• Due to its lower crystallinity of mineral component :
– has the highest Flouride content
– Readily decalcifies in the presence of acidic conditions.

7. Non collagenous
• Non- collagenous proteins- play important role
in matrix deposition, initiation and control of
mineralization and matrix remodelling.
Include: Bone sialoprotein, osteopontin,tenascin,
fibronectin, osteocalcin .
• Proteoglycans- Chondroitin sulphate,hyaluronate,
heparan sulfate, biglycan and osteoadherin.

8. Growth factors- TGFß, bone morphogenetic
proteins (BMP’s),Platelet derived growth
factors, Osteoprotegerin (OPG).
Cementum derived growth factor seen
exclusively in cementum.
 is an insulin like molecule.
 Enhance proliferation of gingival fibroblasts and
periodontal ligament cells.

9. CLASSIFICATION
• ACELLULAR CEMENTUM
• CELLULAR CEMENTUM

10. ACELLULAR CEMENTUM
• Term acellular is UNFORTUNATE because as a
living tissue Cells are an integral part.
• However some layers do not incorporate cells
while other layers do not contain such cells in
their lacunae.
• First to be formed.
• Sharpeys fibers make most of the structure.

11. • Forms during root formation before tooth
reaches occlusal plane.
• Covers approx. cervical 1/3rd (coronal portion)of
the root.
• Does not contain any cells.
• More calcified.
• Formation is slow
• Arrangement of collagen fibers are more
organized

12. CELLULAR CEMENTUM
• Forms after the eruption of tooth once it
reaches occlusal plane.
• Its formation is also in response to the
functional demands.
• Sharpeys fibers occupy a smaller portion.
• Contains cementocytes in lacunae that
communicate with each other by canaliculi.

13. • Covers apical 2/3rd of the root
• Contains cementocytes
• Its deposition is more rapid
• Collagen fibers are irregularly arranged.

14. SHROEDER & PAGE
CLASSIFICATION
1986
• Classified CEMENTUM on the basis of :
– LOCATION
– MORPHOLOGY
– HISTOLOGICAL APPEARANCE

15. 1. Acellular Afibrillar Cementum (AAC)
2. Acellular Exrinsic Fiber Cementum (AEFC)
3. Cellular Intrinsic Fiber Cementum (CIFC)
4. Cellular Mixed Stratified Cementum (CMSC)
5. Intermediate Cementum

17. Acellular Afibrillar
Cementum (AAC)
• FIBERS -ABSENT
• CELLS- ABSENT
• FORMED BY-CEMENTOBLASTS
• LOCATION- CORONAL CEMENTUM
• THICKNESS- 1-15μm

18. Acellular Extrinsic
Fiber Cementum (AEFC)
• FIBERS- DENSELY PACKED
BUNDLES OF SHARPEY’S FIBRES
• CELLS-ABSENT
• FORMED BY –FIBROBLASTS &
CEMENTOBLASTS
• LOCATION -CERVICAL THIRD OF
ROOT
• THICKNESS - 30-230μm

19. Cellular Intrinsic
Fiber Cementum (CIFC)
• FIBERS - INTRINSIC FIBRES
• CELLS - PRESENT
• FORMED BY - CEMENTOBLASTS
• LOCATION - RESORPTION LACUNAE

20. Cellular Mixed
Stratified Cementum
(CMSC)
• FIBERS- EXTRINSIC
SHARPEY’S & INTRINSIC
FIBRES
• CELLS - PRESENT
• FORMED BY - FIBROBLASTS &
CEMENTOBLASTS
• LOCATION - APICAL 1/3
rd
OF
ROOT & FURCATION
• THICKNESS - 100 -1000μm

21. INTERMEDIATE CEMENTUM
• CELLS - CELLULAR REMNANTS OF HERTWIGS
SHEATH
• LOCATION – CEMENTODENTINAL JUNCTION
• THICKNESS - 10μm

22. CEMENTOGENESIS
(Berkovitz)
 Formation of cementum is known as cementogenesis
 Cementum formation takes place along the entire root.
 At the advancing root edge, HERTWIG’S
EPITHELIAL ROOT SHEATH (HERS), which is
derived from the extension of inner and outer enamel
epithelium releases enamel proteins.
 HERS possibly sends inductive message to the
ectomesenchymal cells of pulp.

23.  These ectomesenchymal cells of pulp
now differentiate into odontoblasts
and produce a layer of predentin along
the inner aspect of HERS.
 Once dentin formation is underway,
breaks occur in HERS.
 Therefore the inner layer of dental
follicle comes in contact with
predentin.
 Cells of the dental follicle now
differentiate into CEMENTOBLASTS
which are the main cells responsible
for cementum formation.

24.  Cementoblasts synthesize organic matrix which is
uncalcified and called as cementoid tissue or
precementum
Uncalcified cemental matrix – cementoid

25. Formation of Cementum

26. PTHrP: parathyroid hormone–related protein; BMP: bone morphogenetic
protein
CSF: colony-stimulating factor; EGF: epidermal growth factor
BSP: bone sialoprotein; OC: osteocalcin; OPN: osteopontin.

27. Regeneration versus development: events and cells. While similar events occur
during development and regeneration of tissues, there are clear differences in cell
types involved and in some of the factors promoting cell types involved and in
some of the factors promoting cell

28. MINERALIZATION
• 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.
• Zander & Hurzeler examined the thickness of cementum
on extracted human teeth from individuals of varying ages
& concluded that the mean,linear rate of cementum
deposition on single-rooted teeth is about 3 pm per year,
(but varying greatly with tooth type, root surface area, and
type of cementum being formed).

29. • A similar rate has been found for acellular
extrinsic fiber cementum in premolars and in
nonfunctioning, impacted teeth
• The width of the precementum layer is about 3-5
um.
• 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

30. The development of cementum has been subdivided into:
 Pre-functional stage
 Functional stage
 Prefunctional portion of the cementum is formed during
root development & is extremely long lasting process.
 The functional development of cementum, commences
when the tooth is about to reach the occlusal level & is
associated with the attachment of root to the surrounding
bone & continues throughout life. It is mainly during this
stage that adaptive & reparative processes are carried out
by the biological responsiveness of cementum.

31. CEMENTUM ASSOCIATED
CELLS
Cementoblasts
Cementocytes

32. CEMENTOBLAST S
 Derived from dental
follicle.
 Transformation of
mesenchymal cells of
dental follicle.
 Cemento-progenitor cells
synthesize collagen and
protein polysaccharide.
 These cells have
numerous mitochondria,
a well formed Golgi-
apparatus and large
amounts of granular
endoplasmic reticulum.

33. Histological observation of areas of root resorption has
shown that cementoblasts can arise wherever viable
dentin is exposed to the soft tissue of the periodontal
ligament. Induction of cementoblasts from periodontal
ligament cells can apparently take place throughout life,
as evidenced by physiological areas of cemental repair.
 Cellular turnover among cementoblasts is slow
compared with that in the osteoblasts that line the
alveolus.
 Furthermore, it appears that cementoblasts are capable
of altering their rate of cementum deposition.

34. CEMENTOCYTES
 Cementocytes in lacunae
and the channels in which
their processes extend are
called the canaliculi.
 The central cell mass may
appear rounded or oval &
diameter ranges from 8-15
um.
 The cytoplasm is palely
basophilic and the nucleus
is centrally located.

35. Cementocytes communicate with each other
through a system of anastomosing canaliculi
radiating from their body

36. CEMENTO ENAMEL
JUNCTION
 The junction between the
cementum and enamel at the
cervical region of the tooth is
termed Cemento-Enamel
junction

37.  In about 60% cases cementum overlaps the cervical end of
enamel.
 In approx. 30% of all teeth cementum meets the cervical end
of enamel.
 In 10% cases enamel and cementum do not meet which can
cause accentuated sensitivity because of exposed dentin.
 In about 1.6% of cases enamel overlaps cementum.
four TYPES OF
RELATIONSHIP EXIsTS

38. Journal of Indian Society of Periodontology - Vol 18, Issue 5, Sep-Oct 2014

39. VARIOUS METHODS OF CEJ LOCATION
• Methods for location of CEJ include following two
kinds:
– Conventional
– Modified
A. In conventional methods we have:
• Visual
• Tactile
• By straight explorer
• By periodontal probe; examiner feels for the
cervical line with the tip of the probe
• Radiographic
• Intraoral periapical (IOPA) radiograph
• Bite wings
• RVG

40. B. In modified methods we have:
• Computer linked electronic constant pressure
probes
– Florida probe
– Inter probe/Perio probe
– Birek probe/Toronto automated probe
– Jeff coat probe/Foster miller probe.
Journal of Indian Society of Periodontology - Vol 18, Issue 5, Sep-Oct 2014

41. THE CEMENTO-DENTINAL
JUNCTION (CDJ)
 The terminal apical area of cementum
where it joins the internal root dentin is
called cementodentinal junction or CDJ
 The nature of CDJ is of particular
importance, being of interest
biologically because it forms an
interface (a fit) between two very
different mineralized tissues. It is also
of clinical importance because of the
processes involved in maintaining tooth
function while repairing a diseased root
surface.
 Width of CDJ is 2 to 3um and remains
relatively stable

42. FUNCTIONS
• ANCHORAGE
• ADAPTATION
• REPAIR and RESORPTION

43. ANCHORAGE
• To furnish a medium for the attachment of collagen fibers
that bind the tooth to alveolar bone.
• Connective tissue attachment to the tooth impossible
without cementum.
• EXAMPLE- in hypophosphatasia, loosening and premature
loss of anterior deciduous teeth occurs. The exfoliated
teeth are characterized by an almost total absence of
cementum

44. ADAPTATION
• 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.

45. REPAIR
• 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.

46. RESORPTION OF
CEMENTUM
• Cementum although is less susceptible to
resorption than bone.
• Resorption is carried out by multinuclear
odontoclasts & may continue into the root
dentine.
• Acc. To a study approx 70% of all resorption
areas were confined to the cementum without
involving the dentin.

47. • Local Factors For Resorption
– Trauma from occlusion.
– orthodontic movement
– pressure from malaligned erupting teeth,
– cysts, and tumors;
– Teeth without functional antagonists;
– embedded teeth;
– replanted and transplanted teeth;
– Periapical and periodontal disease.

48. Cemental resorption associated with excessive occlusal forces.
A, Low-power histologic section of mandibular anterior teeth.
B, High-power micrograph of apex of left central incisor shortened by resorption of
cementum and dentin.
Note partial repair of the eroded areas (arrows) and cementicle at upper right

49. • SYSTEMIC FACTORS
– calcium deficiency,
– hypothyroidism,
– hereditary fibrous osteodystrophy,
– Paget's disease.
• IDIOPATHIC

50. • Cementum resorption appears microscopically as
baylike concavities in the root surface.
• Multinucleated giant cells and large mononuclear
macrophages are generally found adjacent to
cementum undergoing active resorption.
• Cementum repair can occur in devitalized as well
as in vital teeth.
• Resorption occurs most commonly in apical third
then middle third followed by gingival third.

51. DEVELOPMENTAL
ANOMALIES ASSOCIATED
WITH CEMENTOGENISIS

52. CEMENTICLES
• Are small, globular masses of cementum
found in approx 35% of human roots.
• May not be always attached to the cementum
surface but may be located free in Pdl.
• These may result from microtrauma, when
extra stress on sharpeys fibers causes a tear in
the cementum.
• Are more commonly found in apical & middle
third of root and in root furcation areas

53. • May develop from calcified epithelial rests;
around small
• spicules of cementum or alveolar bone
traumatically displaced
• into the periodontal ligament; from calcified
• Sharpey's fibers; and from calcified,
thrombosed vessels
• within the periodontal ligament

54. ENAMEL PEARLS
If some HERS cells remain
attached to forming root
surface, they can produce
focal deposits of enamel like
structures called ENAMEL
PEARLS.

55. 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.

56. ABNORMALITIES OF
CEMENTUM
Cemental Hyperplasia or
Hypercementosis –
 Refers to abnormal
thickening of cementum.
 It is largely an age related
phenomenon
 It can be –
Localized to one tooth
Generalized- affect the
entire dentition.

57. • If the overgrowth improves the functional
qualities of the cementum, it is termed as
cementum hypertrophy.
• If the overgrowth occurs in nonfunctional teeth
or if it is not correlated with increased
function, it is termed cemental hyperplasia.

58. 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 excrescenses (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
Hypercementosis

59.  It is usually associated with situations like –
teeth without antagonist
teeth with pulpal and periapical infections
 Hypercementosis of entire dentition may be seen in patients with
Paget's disease.
 Other systemic disturbances include acromegaly, calcinosis,
thyroid goiter, arthritis etc.

60. 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.

61. Cemental aplasia or hypoplasia:
Absence or paucity of cellular cementum.
Hypophosphatasia
 Hypophosphatasia is 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.

62.  Cemental Tear : The detachment
of a fragment of cementum is
described as a cemental tear.
Cemental tears have been reported
in the periodontal literature
associated with localized, rapid
periodontal breakdown.
Cemental
Tear

63. ANKYLOSIS
 Fusion of cementum and alveolar bone and obliteration of the
periodontal ligament is called ankylosis. Results in resorption of
root and its replacement by bone tissue.
 This condition is uncommon.
 Occurs in teeth with cemental resorption.
 It represents a form of abnormal repair.

64. Ankylosis can also occur after:
 Chronic periapical infection
 Tooth reimplantation
 Occlusal trauma
 Around embedded teeth.
 More common in primary dentition

65. 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.

66. 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
resotorative intervention to surgical extraction of affected tooth.

67. EXPOSURE OF CEMENTUM TO ORAL
ENVIRONMENT
• Exposed in cases of gingival recession leading
to pocket formation.
• Permeable to be penetrated by organic
substances, inorganic ions and bacteria.

68. Leading to fragmentation & breakdown of cementum & resulting in areas
of necrotic cementum seperated from tooth by masses of bacteria
Bacterial penetration found as deep as cemento dentinal junction
Collagenous remnants of sharpeys fibers undergo degeneration
Creating environment for bacterial
penetration
87% viable bacteria found in roots
of periodontally non carious teeth
As pocket deepens
Collagen fibers destroyed Cementum exposed to oral
environment

69. CONCLUSION
 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.

70. REFERENCES
 Carranza’s clinical periodontology (10th & 11th
edition)
 Jan Lindhe – Text Book Of Clinical Periodontology
(4th edition)
 Orban’s –Text Book Of Oral Histology And
Embryology 11th & 13th edition
 Tencates – Text Book Of Oral Histology (10th
edition)
• A Color Atlas & Text Of Oral Anatomy & Embryology
– 2nd Edition B.K.B Berkovitz

71.  PERIO 2000 - Dental cementum: the dynamic tissue
covering of the root.
Dieterd . Bosshard &t Knuta . Selvig
 Journal of Indian Society of Periodontology - Vol 18, Issue 5,
Sep-Oct 2014
 PERIO 2000 - Molecular and cell biology of cementum
Nazan E. Saygin, William V. Giannobile&martha J. Somerman