3. Contents:
Introduction
Development of cementum
Molecular factors affecting cementogenesis
Physical characteristics
Chemical characteristics
Histology of cementum
Classification
Cementodentinal junction
Cementoenamel junction
4. Functions
Cementum resorption and repair
Effects of ageing on cementum
Cementum in oral environment
Role of cementum in periodontal disease
Changes in cementum in periodontal pathology
Effectiveness of root planing
Developmental anomalies
Conclusion
References
7. ▪ Begins at the cervical portion of the tooth at the cemento
enamel junction upto the apical foramen.
▪ According to Denton,cementum was first demonstrated
microscopically by Fraenkel and Raschkow (1835) and
Retzius (1836) and has since become a part of general
knowledge in dentistry.
▪ The word cementum originated from the latin word ‘cement’
which means quarried stone.
▪ Anatomically-part of tooth
Functionally-part of periodontium
8. DEFINITION
▪ Cementum is the calcified, avascular mesenchymal tissue that
forms the outer covering of the anatomic root.
(Carranza 13th south asian edition)
▪ Cementum is a hard, avascular connective tissue that covers the
root of the teeth.
(Ten Cate’s oral histology 9th edition)
▪ Cementum is the mineralized dental tissue covering the
anatomic roots of human teeth.
(Orban’s oral histology and embryology 13th edition)
9. ▪ The cementum is a specialized mineralized tissue
covering the root surfaces and, occasionally, small
portions of the crown of the teeth.
(Lindhe 6th edition)
▪ The thin, calcified tissue of ectomesenchymal
origin covering the roots of teeth in which
embedded collagen fibers attach the teeth to the
alveolus.
(Glossary of Dental Implantology)
10. Development of cementum
HERS-Corono apical
extension of IEE and
OEE induces the
secretion of enamel
proteins
Facing the
ectomesenchymal
cells of the dental
papilla diffrentiate
into odontoblasts
Odontoblasts start
forming the
predentin
Some cells from the fragmented root sheath form discrete masses
surrounded by a basal lamina k/as Epithelial cell rests of malassez which
persists in the mature PDL.
11. HERS becomes
interrupted &
ectomesenchymal cells of
inner portion of dental
follicle comes in contact
with the predentin
EM cells of the follicle
receive signals from
dentin & surrounding
HERS cells;diffrentiates
into cementoblasts
Cementoblasts lay down
cemental matrix which
undergoes maturation and
subsequently gets
mineralised resulting into
cementum formation
14. Physical characteristics
▪ Colour-
light yellow in colour
dull surface-lacks lusture
darker hue than enamel
▪ Hardness-
less than dentin
▪ Permeablility-
more permeable than dentin
decreases with age
▪ Thickness-
thinnest at CEJ 20-50 µm
thickest at apex 150-200µm
15. Chemical characteristics
▪ On dry weight basis,a fully formed permanent teeth consists
of-
Inorganic substance
45-50%
• Calcium phosphate in the form of hydroxy apatite crystals
Ca10(PO4)6(OH)2
• Highest fluoride content
16. type I COLLAGEN fiber
And protein polysaccharide-
proteoglycans,osteopontin,osteonectin,osteocalcin,
osteonectin, fibronectin,bone sialoprotein.
Other collagen –Type III,V,VI,XII
17. Suggested Function Related to Cementogenesis
Growth Factors
Transforming
growth factor β
superfamily
(including bone
morphogenetic
proteins)
Reported to promote cell differentiation and
subsequently cementogenesis during
development and regeneration.
Platelet-derived
growth factor
and insulin-like
growth factor
Existing data suggest that platelet-derived growth
factor alone or in combination
with insulin-like growth factor promotes cementum
formation by altering cell
cycle activities.
Fibroblast growth
factors
Suggested roles for these factors are promoting cell
proliferation and migration
and also vasculogenesis—all key events for formation
and regeneration of
periodontal tissues.
Adhesion Molecules
Bone
sialoprotein
Osteopontin
These molecules may promote adhesion of selected
cells to the newly forming
root. Bone sialoprotein may be involved in promoting
mineralization, whereas
osteopontin may regulate the extent of crystal
growth.
Epithelial/Enamel
Proteins
Proteins
Epithelial-mesenchymal interactions may be involved
in promoting follicle cells
18. along a cementoblast pathway.
Some epithelial molecules may promote periodontal
repair directly or indirectly.
Collagens Collagens, especially types I and III, play key roles in
regulating periodontal
tissues during development and regeneration.
In addition, typeXII may assist in maintaining the
periodontal ligament space
versus continuous formation of cementum.
Gla Proteins
Matrix Gla
protein/bone Gla
protein
(osteocalcin)
These proteins contain γ-carboxyglutamic acid, hence
the name Gla proteins.
Osteocalcin is a marker for cells associated with
mineralization—that is,
osteoblasts, cementoblasts, and odontoblasts—and is
considered to be a regulator
of crystal growth. It has also been proposed to act as a
hormone regulating energy
metabolism through several synergistic functions
favoring pancreatic β-cell
proliferation, increasing insulin secretion (in the
pancreas) and sensitivity in
peripheral tissues, and promoting energy expenditure (in
brown adipose tissue)
and testosterone production by Leydig cells in testes.
Matrix Gla protein appears
to play a significant role in preventing abnormal ectopic
calcification.
19. Transcription Factors
Runt-related
transcriptionfactor 2
(Runx-2)
Osterix
As for osteoblasts, these may be involved in
cementoblast differentiation.
Signaling Molecules
Osteoprotegerin These molecules mediate bone and root resorption
by osteoclasts.
Receptoractivated
nuclear
factor κB ligand
Receptoractivated
nuclear
factor κB
Sclerostin Antagonist of Wnt and promotes cementum
formation
Wingless-related
integration site
(Wnt)
Regulates stem cell populations and
differentiation of cementoblasts
Cementum-Specific Proteins
Cementum
protein 1
(cementumderived
protein
23)
May play a role as a local regulator of cell
differentiation and extracellular matrix
mineralization.
20. Histology of cementum
▪ Histologically,cementum shows
a. Cells,fibers,ground substance
b. Cemento enamel junction
c. Cemento dentinal junction
23. After the matrix is laid down,it begins mineralisation
The cells are found lining the root surface
24. • Cementocyte
Spider shaped cells -cellular
cementum.
During the formation of cellular
cementum, cementoblasts get
entrapped within their own
cemental matrix due to rapid
deposition resulting
in the formation of cementocyte.
25. Similar to osteocytes,they lie in
lacunae.
Canalicular processes branch and
anastosomes with adjacent cells.
These processes are directed
towards PDL.
Deeper layers of cementum(60µm
from nutrition)cementocytes shows
definite signs of degeneration such
as cytoplasmic clumping,
vesiculation & sometimes empty
lacunae.
26. Cementoclast
Found in howship’s lacunae
Unilocular/multilocular
Function-resorption of
cementocytes
Major role-resorption and repair
27. Incremental lines of salter
▪ These lines represent rhythmic periodic deposition of cementum
▪ Appears as dark lines running parallel
to root surface
Highly mineralized areas with less
collagen & more ground substance
Seen in both acellular and cellular
cementum
Predominantly in acellular cementum
28. Types of cementum
i.Based on location
a.radicular cementum
b.coronal cementum
ii.Based on cellularity
a.Acellular cementum
b.Cellular cementum
iii.Based on presence of collagen fibers in matrix
a.Afibrillar cementum
b.Fibrillar cementum
29. ACELLULAR CEMENTUM CELLULAR CEMENTUM
• Primary cementum • Secondary cementum
• Present on cervical 3rd or half • present on apical 3rd of the root
of the root
• cells are absent • cells are present
• forms before the tooth reaches • forms after the tooth reaches the
the occlusal plane the occlusal plane
• more calcified • less calcified
• sharpey’s fibers are main compo • sparse number of sharpey’s fibers
-nent are present
• perpendicular to root surface • parallel to root surface
• rate of development is faster • rate of development is slower
•incremental lines are wide apart • incremental lines are closer
• thickness ranges from 30-230µm • thickness ranges from 150-200µm
30. iv. Based origin of the matrix fibers
a.extrinsic fiber
b.intrinsic fiber
c.mixed fiber
Extrinsic fiber-
− Also known as ‘sharpey’s fiber’
− Embedded portion of the principal
fibers of PDL
− Formed by fibroblasts
31. Intrinsic fiber
− Belongs to cementum
− Formed by cementoblast
Intrinsic
fibers of
cementum
32. Mixed fiber
− Composed of extinsic sharpey’s fiber & intrinsic fiber
− Co-product of cementoblast and fibroblast
Mixed fibers of cementum
33. Schroeder classification(1986)
i. Acellular afibrillar cementum(AAC)
ii. Acellular extrinsic fiber cementum(AEFC)
iii. Cellular mixed stratified cementum(CMSC)
iv. Cellular intrinsic fiber cementum(CIFC)
34. Acellular afibrillar cementum(AAC)
▪ contains neither cells nor extrinsic or intrinsic
collagen fibers.
▪ only mineralised ground substance.
product of cementum,seen in crown portion
of tooth
▪ thickness - 1-15µm
▪ no known fuction around CEJ.
35. Acellular extrinsic fiber cementum(AEFC)
densely packed bundles of sharpey’s fiber,
no cells.
co-product of fibroblast & cementoblast.
found in cervical 3rd of root,may extend
apically.
thickness- 30-230µm
function-anchorage in especially single
rooted teeth.
.
.
36. Cellular mixed stratified cementum(CMSC)
▪ composed of both intrinsic & extrinsic
sharpey’s fibers.
▪ may contain cells.
▪ co-product of fibroblast & cementoblast.
▪ function-adaptation & repair
37. Cellular intrinsic fiber cementum(CIFC)
-contain cells but no extrinsic collagen fiber.
-formed by cementoblasts.
-fills the resorption lacunae.
38. Intermediate cementum-
is a poorly defined zone near the cementodentinal junction
of certain teeth that appear to contain cellular remnants of
Hertwig sheath embedded in calcified ground substance.
- seen in apical 3rd of root and apices, & in furcation area.
-thickness- 10-1000µm
-function-adaptation of fibers
39. Cementodentinal junction
▪ Interface between dentin and
cementum.
▪ In deciduous teeth-scalloped
permanent teeth-smooth.
▪ Areas of dentin adjacent to CDJ
granular in ground substance
due to coalescing and looping the
terminal portion of dentinal tubules
and is called ‘Tomes Granular Layer’.
40. Terminal apical area of cementum where it joins
the inteernal root canal dentin.
During RCT,the obturating material should be at
CDJ.
No increase /decrease in width(2-3µm)
41. Cementoenamel junction
▪ It is the preface between cementum & enamel at cervical region
of teeth is variable.
▪ It is also an important landmark as a clinical consideration while
scaling and root planing.
42. Funtions of cementum
▪ Provides medium for the attachment of collagen fibers of PDL.
▪ Cementum is harder than alveolar bone & is avascular and
doesn’t show resorption on masticatory or orthodontic forces.
43. ▪ Thus during heavy orthodontic forces tooth integrity is
maintained & alveolar bone being elastic in nature changes its
shape,fulfilling orthodontic requirements.
44. ▪ Acts as a covering for root surface, a seal for open dentinal
tubules.
▪ Prevents dentinal tubules from
sensitivity.
Reparative nature
▪ Aid in maintaining the teeth in functional occlusion (in
chronic bruxism, deposition of cementum on apical aspect of
the teeth) [passive eruption].
45. Cementum resorption and repair
▪ Permanent teeth do not undergo phyioslogic resorption as
primary teeth.
▪ Local factors-
▪ Systemic factors- Ca deficiency,
hypothyroidism,paget’s disease,
Hereditary fibrous
osteodystrophy
▪ Microscopically ,bay-like concavities seen over tooth surface.
Multi nucleated giant cells, mononuclear macrophages are
generally found adjacent to the site of active resorption.
▪ Painless
46. ▪ Reversal line-?
▪ Repair – i.anatomic repair
ii.functional repair
▪ Occurs in vital and non vital tooth both
47. Effects on ageing in cementum
▪ Becomes irregular due to calcification of some bundle fibers
where they were attached to cementum
▪ Cemental width may increase 5-10 times
(deposition continues after eruption)
▪ Increase in width is greater apically &
lingually
▪ In ageing, a continuous increase of
cementum in apical zone may
result in obstruction of apical
foramen
48. What happens to cementum when
exposed to oral cavity?
Cementum becomes exposed to the oral environment in cases
of gingival recession and as a consequence of loss of
attachment in pocket formation
The cementum is sufficiently permeable to be penetrated in
these cases by organic substances, inorganic ions, and
bacteria
Bacterial invasion of the cementum occurs commonly in
periodontal disease
Cemental caries
49. Clinical considerations
In periodontal pockets, pathologically exposed cementum,
altered cementum interfere with healing
Root planing (hypomineralised cementum)
Cellular cementum- avascular, no nerve supply -scaling
produces no pain, but if cementum is removed, dentin is
exposed causes sensitivity
Precementum – natural barrier to excessive apical
migration of junctional epithelium
Biomodification of root surface
50. Role of cementum in
periodontal disease
The surface on which plaque &
calculus is attached, the role
therapy is to remove these
accretions as a part of the
treatment plan
It forms the inner wall of the
periodontal pocket.
This tissue is relatively static as
compared to surrounding dynamic
tissues, so any change will have
long term effects.
Its intimately involved in all phases
of the PD process so it must be
returned to a healthy state before
any progress in disease control,
soft tissue regeneration & repair.
ROLE OF CEMENTUM IN
PERIODONTAL DISEASE
DCNAVol 24. No. 4, 1980
by Joseph J. Aleo
51. Changes in cementum associated
with periodontal disease
▪ Structural changes
▪ Pathologic granules in exposed cementum by Bass and Benson
– proven by SEM studies that vacuole like formations exist
▪ Partial demineralisation by Selvig et al
▪ Reprecipiation of dissolved minerals
▪ Decrease or loss of cross banding of collagen
▪ Subsurface condensation of organic material of exogenous
origin
52. ▪ Chemical changes
▪ increase in calcium & phosphate levels by 7-10% -increased
radiopacity in electron probe analysis by Selvig & Hal
▪ Increase in flouride coincides with Ca & P (1.3-1.9%)
▪ Decrease in sodium levels (0.3%)
▪ Absorption of Ca P & F –highly calcified –resistant to decay
▪ Absorbed materials –foreign to surrounding tissues
▪ Demineralisation/mineralisation of cementum –ability to
absorb or deplete mineral or organic compounds
53. Cytotoxic changes
▪ Effects on Cell proliferation
-Hatfield & Baumhammers- inhibitory substance penetrates
surface of exposed cementum that prevents growth of epithelial
cells in tissue culture
-Presence of endotoxins- Aleo et al 1974 –limit fibroblast
proliferation – detrimental to the arrest of disease
-Cementum bound endotoxins -50 times more toxic –heat
resistant toxic substances (Limulus amoebocyte lysate)
-Destructive physical changes –cavitation, partial
demineralisation
54. Cytotoxic changes
• Effects on Cell attachment
• Cultured human gingival fibroblasts do not attach
to the diseased tooth –Aleo et al 1975
55. Effects on Cell attachment
• Inhibitory principle of matrix
• Morris 1975
• diseased roots inhibited the development of implanted
marrow whereas demineralised healthy roots did not
• demineralised diseased roots showed most inhibtion (masked
by superimposed apatite crystals)
• toxins must have seeped into root matrix during pocket
formation & demineralisation removed the toxins allowing
development of marrow
56. ▪ According to inhibitory principle of matrix –
▪ drastic phenol extraction usually required to
remove toxins from bacterial cell wall is not
necessary to make diseased cementum receptive
to cell attachment – milder treatments may
accomplish the same thing
57. ▪ in early and moderate periodontitis -acellular
cementum (coronal half of the root) is affected
▪ damage extends to cellular cementum in most
advanced and furcally positioned lesions
▪ these surfaces are almost always covered by
cellular cementum during successful regeneration;
whether this is adequate is unclear.
(MacNeil and Somerman, 1999)
58. Role of cementum molecules in
periodontal regeneration
▪ growth factors and adhesion molecules present in
cementum are also active toward cells of the
gingiva, periodontal ligament, and alveolar bone
(Narayanan and Bartold,1996; Bartold et al.,
2000)
▪ it is possible that these cementum components
have the potential to participate in the
regeneration of these tissues
59. ▪ not significant because the growth factors present
in cementum remain bound to the cementum
matrix
▪ even if the inflammatory process releases them,
their relative concentrations are likely to be less
than those available from the blood and
inflammatory cells
▪ therefore, contributions by cementum molecules
to the regeneration of other periodontal tissues
are likely to be marginal
60. Effectiveness of Root planing
in removing toxins
▪ In vitro- human gingival fibroblasts attach normally to
periodontally diseased roots that have diseased
cementum mechanically removed
▪ In vivo- Jones & O’Leary 1978
▪ -subgingival root planed
-supragingival root planed
-periodontally involved with calculus
-gross scaled in vitro
-healthy uninvolved
▪ All were planed and checked with Hartzell No. 3 explorer
& then assayed for endotoxin –planed had 1ng more
endotoxin
61. Chemical modification of
cementum
Addition of zinc to cultures relieved endotoxin induced
depression of cellular proliferation.
▪ Chelation of zinc enhanced cellular toxicity of endotoxin -
Aleo et al
▪ Studies analysing effect of zinc on cell attachment are still
underway
▪ Register & Burdick- tested effects of partial
demineralisation by acid on reattachment (adult dogs)
▪ Results –production of cementum pins –reattachment with
cementogenesis
–repair of chronic interproximal defects
–complete alveolar bone repair over labial defects by 1 year
62. Role of cementum in periodontal
regeneration
▪ Not significant because the growth factors present in
cementum remains bound to the cemental matrix.
▪ Even if the inflammatory process releases them, their
relative concentrations are likely to be less than those
available from the blood & inflammatory cells.
▪ Therefore,contributions by cementum molecules to the
regeneration of other periodontal tissues are likely to be
marginal.
63. DEVELOPMENTAL ANOMALIES
LOCATED ON CEMENTUM
▪ Enamel Projections
If amelogenesis does not stop before
the start of root formation, enamel
may continue to form over portions
normally covered by cementum.
64. ▪ Enamel Pearls
This consists of globules of enamel
on the root surface in cervical region
(act as plaque retentive areas)
65. Hypercementosis
▪ refers to a prominent thickening of the cementum .
▪ It may be localized to one tooth or
affect the entire dentition
(Pagets disease)
▪ occurs as a generalized
thickening of the cementum,
with nodular enlargement of
the apical third of the root.
66. The etiology of Hypercementosis
▪ spike like type of hypercementosis -results from
excessive tension from orthodontic appliances
or occlusal forces
▪ generalized type -occurs in teeth without antagonists,
hypercementosis is interpreted as an effort to keep pace
with excessive tooth eruption
▪ In teeth subject to low-grade periapical irritation arising
from pulp disease, it is considered compensation for the
destroyed fibrous attachment to the tooth
67. Factors leading to hypercementosis
• TFO
• Orthodontic movement
• Pressure from non-aligned erupting
tooth
• Cysts,tumors
• Teeth without functional antagonist
• Periapical disease
Local factors
• Calcium deficiency
• Hypothyroidism
• Hereditary fibrous osteodystrophy
• Paget’s didsease
Systemic
factors
68. ▪ Other systemic disturbances that may lead to ormay be
associated with hypercementosis include
acromegaly,arthritis, calcinosis, rheumatic fever, and
thyroid goiter.
69. Cementoblastoma
Only neoplasm of cementum
Cementum like tissue is deposited
in roots of tooth as irregular or rounded
mass.
•Age <25
Often involves the mandibular molars
or premolars
Tooth usually has a vital pulp
Attached to root and may cause its resorption, may involve the
pulp canal, grows slowly, tends to expand the overlying cortical
plates
Enlargement produced is usually asymptomatic
70. Cementoma
•Benign cementoblastoma / Cemental Dysplasia
•Represents an unusual reaction of bone
•Caused due to occlusal trauma
•Present usually at apex of mandibular
incisors
•Almost exclusively found in black
persons
•Age 20-40 years
•Expansion of jaw
71. Concrescence
▪ Form of fusion which occurs after root
formation has been completed.
▪ Thought to arise as result of traumatic
injury or crowding of teeth with
resorption of interdental bone so that
two roots are in approximate contact
and become fused by deposition of
cementum between them.
▪ May occur before or after teeth have
erupted.
72. Hypophosphatasia
▪ This is a hereditary disease that is characterized by the total
absence of cementum.
▪ It results in early loss of the teeth.
▪ It occurs because of the deficiency of enzyme alkaline
phosphatase in serum and tissues.
73. Cementicles
calcified bodies sometimes seen in the periodontal
ligament.
may be round or ovoid.
singly or in multiple numbers near the cemental surface.
Origin
not established.degenerated epithelial cells form the nidus
for their calcification.
also believed could be due to trauma, the calcification of the
ends of the sharpey’s fibers occurs that can result in the
formation.
74. ▪ Types of cementicles:
▪ Free cementicles : lamellated
cemental
bodies that lie freely in the PDL.
▪ Attached cementicles : cemental
bodies which are attached to the
root surface.
75. Ankylosis
▪ •Fusion of the cementum and alveolar
bone with obliteration of the periodontal
ligament is termed ankylosis.
•occurs in teeth with cemental resorption,
may represent a form of abnormal repair.
•may develop after chronic periapical
inflammation, tooth replantation, occlusal
trauma.
•results in resorption of the root and its
gradual replacement by bone tissue.
76. Conclusion
▪ Cementum is an important tissue of the periodontium,
the attachment apparatus of the tooth and has an
important role in tooth movements.
▪ Cementum deposition is a continuous process but this
tissue is comparatively static as compared to the
surrounding dynamic tissues therefore it has to be taken
in account while performing various dental procedures.
77. References
▪ Carranza Clinical periodontology south asian edition 13th
▪ CEMENTUM- Recent concepts related to periodontal
disease therapy – Joseph J. Aleo (DCNA)
▪ LINDHE’s Clinical periodontology & implantology,6th edition
▪ Shafer’s textbook of oral pathology, 6th edition
▪ Orban’s Oral histology & Embryology edition,14th edition
▪ Tencate’s oral histology 9th edition
