This document provides an overview of cementum, including its physical characteristics, composition, functions, classification, locations, abnormalities, and more. Cementum is the avascular, mineralized tissue covering tooth roots. It is composed of cells, collagen fibers, and hydroxyapatite crystals. Cementum functions to provide anchorage for fibers attaching teeth to bone and aids in adaptation and repair. It can be classified based on presence of cells, fiber origin, location, and matrix composition. Abnormalities include aplasia, hypoplasia, and hypercementosis.

1. CEMENTUM
PERIDONTOLOGY
By Safura Ijaz
Batch’24 Dental Technology

2. CONTENTS
 INTRODUCTION
 PHYSICAL CHARACTERISTICS
 COMPOSITION
 FUNCTIONS
 CLASSIFICATION
 CEMENTO-ENAMEL JUNCTION (CEJ)
 CEMENTO-DENTINAL JUNCTION (CDJ)
 CEMENTUM RESORPTION AND REPAIR
 ABNORMALITIES OF CEMENTUM

3. INTRODUCTION

4. “Cementum is avascular, mineralized connective
tissue that forms the outer covering of the anatomic
root.”

5. PHYSICAL
CHARACTERISTICS

6.  Hardness < Dentin
 Light yellow in color
 Permeability of cellular cementum is greater
than Acellular cementum and this
permeability diminishes with age.
 Thinnest on the coronal half of the root i.e. 16
to 60 μm.
 Thickest in the apical 3rd and in the furcation
area i.e. ≤ 150 to 200 µm.
 Thicker in distal surfaces than in mesial
surfaces because of mesial drift.

7. COMPOSITION

8. Cementum
Cells
Cementoblasts
Cementocytes
Cementoclasts
Extracellular
Matrix
Organic
Matrix
Fibers
Collagenous
Proteins
Collagen
type – I
(90%)
Collagen
type – III
(5%)
Extrinsic
fibers
Intrinsic
fibers
Ground Substance
Non- Collagenous
Proteins
Proteoglycans
Glycoproteins
Phosphoproteins
Alkaline phosphtase
Inorganic
Matrix
Hydroxyapatite
Crystals

9. SOURCES OF COLLAGEN
FIBERS
There are 02 main sources of collagen fibers:
1. Extrinsic fibers: “Fibers that belong to
the principal fibers of
PDL (Sharpey’s fibers)
and formed by fibroblasts.”
2. Intrinsic fibers: “Fibers that belong to the
cementum matrix and
formed by cementoblasts.”

10. FUNCTIONS OF
CEMENTUM

11. Followings are the functions of cementum
 Anchorage : Provides a medium for the
attachment of collagen fibers that bind tooth
to the alveolar bone
 Adaptation: In response to tooth wear and
movement.
 Repair : Associated with repair of
periodontal tissues and damage to roots
such as fractures and resorptions.

12. CLASSIFICATION OF
CEMENTUM

13. Cementum can be classified on the
basis of :
1. Presence or absence of cells
a) Acellular cementum
b) Cellular cementum
2. Origin of fibers
a) Extrinsic fiber cementum
b) Intrinsic fiber cementum
3. Location
a) Coronal cementum
b) Radicular cementum
4. Presence or absence of collagen fibrils in the
matrix
a) Fibrillar cementum
b) Afibrillar cementum

15. Acellular cementum Cellular cementum
Forms before tooth reaches occlusal plane -
first formed cementum / primary cementum
Forms after tooth reach
plane i.e. secondary ce
Absent Present (Cementocytes
Cervical 3rd or half of the root
i.e. coronal portion of the root
Apical portion of the roo
furcation area
mation Slower Faster
n More calcified Less calcified
nt of collagen Regularly arranged Irregularly arranged
lines More i.e. closer together Sparse i.e. wide apart
bers and
cation
More and completely calcified Less and completely or
calcified
Thin cementum i.e. 30 to 230 µm Thick cementum i.e.10
Anchorage Adaptation and Repair

16. SCHROEDER’S
CLASSIFICATION
On the basis of presence or absence of cells
and collagen fibers in matrix, location and
origin of fibers, SCHROEDER classified
cementum into 05 different types.
1) Acellular afibrillar cementum
2) Acellular extrinsic fiber cementum
3) Cellular mixed stratified cementum
4) Cellular intrinsic fiber cementum
5) Intermediate cementum

17. Acellular
Afibrillar
Cementum
(AAC)
Acellular
Extrinsic Fiber
Cementum
(AEFC)
Cellular Mixed
Stratified
Cementum
(AMSC)
Cellular
Intrinsic Fiber
Cementum
(AIFC)
Absent Densely packed
bundles of
Sharpey’s fibers
Extrinsic and
intrinsic fibers
Intrinsic fibers
from the
cementum matrix
Absent Absent Present Present C
o
Cementoblasts Fibroblasts and
cementoblasts
Fibroblasts and
cementoblasts
Cementoblasts
Coronal cementum
i.e. CEJ
Cervical 3rd of the
root and may
extend farther
apically
Apical 3rd of the
root and in
furcation area
Resorption
lacunae
C
j
1 – 15 µm 30 – 230 µm 100 – 1000 µm

19. CEMENTO-ENAMEL
JUNCTION

20. PATTERNS OF CEJ
TYPE – 1 : In about 60% - 65% cases cementum overlaps the
enamel.
TYPE – 2 : In about 30% cases edge-to-edge butt joint exists.
TYPE – 3 : In about 5% - 10% cases cementum and enamel fails to
meet which cause accentuated sensitivity because of
exposed dentin.

21. CEMENTO-DENTINAL
JUNCTION

22. “The terminal apical
area of cementum
where it joins the
internal root dentin is
called CDJ.”
It is 2 – 3 µm wide
its width remains
same i.e. stable with
age.
During RCT,
obturating material
should be at CDJ.

23. CEMENTUM
RESORPTION AND REPAIR

24. “It is the process by which old cementum is removed
and replaced by new cementum.”
Cells responsible for resorption of cementum:-
These cells are found adjacent to the cementum
that is undergoing active resorption.
 Multinucleated giant cells
 Large mononuclear macrophages
Cells responsible for repair of cementum:-
 Cementoblasts
 Cells rest of Malassez
 Growth factors
Members of transforming growth factors super-family
Platelet derived growth factor
Insulin like growth factors
Enamel matrix derivatives

25. CAUSES OF CEMENTUM
RESORPTION
Local Factors Systemic Factors
 Trauma from occlusion
 Orthodontic movement
 Pressure from malaligned
erupting teeth
 Cysts and tumors
 Teeth without functional
antagonist
 Embedded teeth
 Replanted and transplanted
teeth
 Periapical and periodontal
disease
 Calcium deficiency
 Hypothyroidism
 Paget’s disease
 Hereditary fibrous
osteodystrophy

26. ABNORMALITIES OF
CEMENTUM

27. Abnormalities of cementum can be:
Cemental Aplasia “Absence of cellular cementum.”
Cemental Hypoplasia “Paucity of cellular cementum.”
Cementum Hyperplasia
Or
Hypercementosis
“Excessive deposition of cementum.”
• It is largely an age related phenomena.
• It can be localized to one tooth or
generalized i.e. affect the entire dentition.
Causes :-
• Loss of antagonist
• Inflammation of the root
• Trauma to the root
Treatment:-
• It itself does not need treatment.
• It could pose a problem if an affected
tooth requires extraction.
• In a multi-rooted tooth, sectioning of the
tooth may be required before extraction.

28. ANKYLOSIS
“Fusion of cementum and the alveolar bone
with the obliteration of PDL is called
ankylosis.”
Causes of ankylosis:-
 Cemental resorption
 Chronic apical inflammation
 Tooth replantation
 Occlusal trauma

29. ANKYLOSIS

30. EXPOSURE OF CEMENTUM TO
THE ORAL ENVIRONMENT
Cementum becomes exposed to the oral
environment in cases of:
 Gingival recession
 Loss of attachment in resulting in pocket
formation
This results in:
 Periodontal diseases
 Cementum caries
because cementum is sufficiently
permeable to be penetrated by organic
substances, inorganic ions, and bacteria.