Cementum is the calcified tissue that covers the root surface of teeth. It is less hard than dentin and yellow in color. Cementum contains calcium and collagen and is not vascular. It is produced by cementoblast cells and plays an important role in attaching periodontal ligaments and protecting the root. With age, cementum can thin and recede, exposing the root and increasing risk of erosion, sensitivity, and tooth loss if not protected. Maintaining good oral hygiene is important for cementum health.

1. CEMENTUM
Cementum is a specialised hard layer of calcified
mesenchymal tissues which forms the outer
covering of the anatomical root. It is also called as
Substantia Ossea Cementum is the part of
Periodontium . Human Cementum is avascular
& has no innervations.

3. PHYSICAL PROPERTIES
1. Hardness : Hardness less than dentin. Least
calcified
2.Colour : Light yellow in colour. Dull surface
(Lack of Lusture) Darker hue than enamel.
3. Permeability : More permeable than dentin.
Permeability decreases with age.
4. Thickness : Cellular Cementum : 16-60 micron.
Acellular Cementum : 150-200 micron
Cementum is similar to bone in that it contains
calcium; but, as opposed to bone, it is avascular. This
means it is not supplied by blood vessels.

4. CHEMICAL PROPERTIES
Inorganic Matter (45-50%) Organic Matter (50-
55%) Mainly Hydroxyapatite Mainly Type-I
collagen Ca 10 ( PO 4 ) 6 (OH) 2 &
interfibrillar ground Fluoride content is
highest Substance consist of than other
calcified tissues Proteoglycans of body.

5. CLASSIFICATION
I. Based on time of formation Primary
Secondary
II. Based on Presence or Absence of Cells
Cellular A cellular
III. Based on Fibers Extrinsic Intrinsic
According to above findings cementum
classified as:

6. 1.Acellular Afibrillar Cementum
2. Acellular Extrinsic Fiber
Cementum.
3. Cellular Mixed Stratified
Cementum.
. 4. Cellular Intrinsic Fiber
Cementum.

7. CELLULAR CEMENTUM

9. INTERMEDIATE CEMENTUM
It is an ill-defined zone near the
cementodentinal junction of certain teeth that
appears to contain celluar remnants of
Hertwig’s sheath embedded in calcified
ground substances.

10. . DEFFERENCE ACELLULAR CEMENTUM CELLUAR
CEMENTU M
1. First formed Secondary Cementum
2. Present on cervical third or half of the
root. Mainly on apical third of root.
3. It does not contain cells. It contain cells
called cementocytes in individual spaces
lacunae.

11. 4. It is formed before the tooth reaches the
occlusal plane. Formed after the tooth reaches
the occlusal plane.
5. More calcified. Less Calcified.
6. Sharpey’s fibers are main compenent which
inserted at approximately right angles onto the
root surface. Sharpey’s fibers occupy smaller
portion & occpy other fibers that are arranged
parallel to the root surface.

12. SHARPEY’S FIBERS
Terminal portions of the principal fibers that
insert into cementum & bone are termed as
“Sharpey’s Fibers”. These have a principal
role of supporting the tooth within jaw

14. CELLS OF CEMENTUM
: 1. Cementoblasts:
Cementoblasts synthesize collagen& protein polysaccharides that
form organic matrix of
Cementum
 specialized cementoblast cells are stimulated to produce new
cementum around the root of the tooth.
 The cementoblasts are created within the dental pulp
2. Cementocytes :
During formation of cellular cementum, the cementoblasts become
incorporated into the cemental matrix. These cells are known as
cementocytes. The cementocytes lie in spaces known as lacunae

17. CEMENTOGENESIS
 Cementum develops from the activity of
mesenchymal cells of dental follicle after
fragmentation of the epithelial root sheath.
After formation of dentin, loss of continuity
occurs in the epithelial root sheath. This
allows adjacent cells of the investing layer of
the dental follicle to come to lie on surface of
root dentin & these are induced to differntiate
into cementoblasts.

18. CEMENTOENAMEL JUNCTION
 The interface between the Cementum &
Enamel at the cervical region of tooth is
known as cementoenamel junction
 It is of 3 types:-
 Pattern I Pattern II Pattern III : Overlapping
Type (60%) Butt joint (30%) Gap joint (10%)

20. CEMENTODENTINAL JUNCTION
 It is interface between the dentin &
cementum. Scalloped in deciduous teeth &
smooth in the permanent teeth.

22. FUNCTIONS OF CEMENTUM
 The primary functions of cementum are to protect the
root and assist in holding the tooth securely in the
gingiva socket
 1-Cementum provide a medium for the attachment to
the collagen fibers of periodontal ligament.
 2- Cementum is hard & has no blood supply, It does
not show resorption under masticatory or orthodontic
forces. Thus, during heavy orthodontic forces, tooth
integrity is maintained & alveolar bone being elastic in
nature changes its shape, fulfilling the orthodontic
requirement

23. 3-Cementum has property of continuous deposition
& does the patch work or repair for the damage such
as fracture or resorption of tooth surface.
4- Regular Cementum deposition at the root apex,
helps to replenish the lost tooth height due to
occlusal wear or helps in passive eruption of teeth.

24. CEMENTAL HYPERPLASIA & HYPERTROPHY
 HYPERPLASIA:-
 Cementum overgrowth when growth does
not help in increasing function of the tooth.
eg. due to periapical infection.
 HYPERTROPHY:-
 If Cementum overgrowth improves or helps
in the functioning of teeth, this is called as
cemental hypertophy. eg. Cemental spike
develps from extensive orthodentic force

26. CEMENTICLES
 CEMENticles are round lamellated cemental
bodies that lie free in the PDL or are attached
to the root surface. Mostly found in aging
persons or at the site of trauma

29. CEMENTOMA
 is also called benign cementoblastoma or
cemental dysplasia. These are cemental
masses situated at the apex of the root which
are slowly growing odontogenic neoplasm
and may cause expansion of jaw

30. CEMENTAL RESORPTION & REPAIR :
 CAUSES OF CEMENTAL RESORPTION :-
 1- Local Causes:-
 1.trauma
2.cysts and tumors
3.perapical pathology
4.excessive orthodontic force
4.embedded teeth
5.replante and transplanted teeths

 2- Systemic Causes :-
 1.deficiency of calcium
2.deficiency of vitamin A ad D
3.hypothyroidism

31. CEMENTAL REPAIR
 Repair of cementum is a process to heal the
damage caused by resorption or cemental
fracture.
 1-anatomic repair:- the root outline is re-established
as it was befor resorption. It
generally occurs when the degree of destruction
is low
 2-functional repair:therese not re-establised
 to improve the function of tooth .thus called
functional repair

32. AGING OF CEMENTUM
 1- Surface become rough.
 2- Cemental Resorption.
 3- Permeability Decreases.
 4- More Cemental deposition may lead to
closure of the apical foramen.

34. The primary risk to the health of the cementum
is gingiva recession. This generally occurs over age 40 and is due to either
excessively hard brushing or the initial stages of gum disease. With gingiva
recession, the gingiva tissue pulls away from the tooth and begins to expose
the cementum and the root.
Cementum is thinnest at the interface with the enamel, which generally is the
area that becomes exposed. This makes it highly vulnerable to erosion during
brushing. Erosion of the cementum can cause tooth sensitivity, lead to decay,
and cause root damage. Excessive damage to the cementum can cause tooth
loss through the release of the periodontal ligaments that hold the tooth in
place.