DEVELOPMENT OF CEMENTUM
RESORPTION AND REPAIR
CEMENTUM IN PERIODONTAL DISEASE
AGE CHANGES IN CEMENTUM
ANOMALIES IN CEMENTUM
The periodontium consists of those tissues which
surrounds & support the tooth & is composed of: gingiva,
PDL, cementum & alveolar bone.
Cementum was first demonstrated microscopically in 1853
by Frankel and Raschkow.
The word cementum comes from the Latin word “cement”
which means quarried stone.
Thin, calcified tissue of ectodermal origin covering the roots
of the teeth in which embedded collagen fibers attach the
teeth to alveolus.
Calcified, avascular mesenchymal tissue that forms the outer
covering of the anatomic root.
(Carranza 10th ed)
Mineralized connective tissue that covers the roots of the
(Listgarten 1st ed)
5. DEVELOPMENT OF CEMENTUM
HERS derived from the inner & outer enamel
epithelium induces secretion of enamel protein.
Sends inductive signal to ectomesenchymal pulp
cells to secrete pre-dentin by differentiating into
HERS becomes interrupted
Ectomesenchymal cells from the inner portion of the
dental follicle come in contact with pre-dentin by
differentiating into cementoblasts
Cementoblasts lay down CEMENTUM
6. PHYSICAL CHARACTERISTICS
Hardness- less than dentin.
Colour- light yellow with dull surface & lighter than dentin.
thinnest at CEJ (20-50 µm)
thickest at apex (150-200 µm)
As age progress- cementum diminishes.
7. CHEMICAL CHARACTERISTICS
Organic content and water - 50 – 55%
Inorganic content - 45 – 50 %
• Collagen fibers embedded in an interfibrillar ground
substance consisting of glycoproteins.
• Types of collagen :-
Type I, Type III, Type V, Type IX, Type XIV
• Cementum proteins.
8. CEMENTUM PROTEINS
Proteoglycans creates the cemental incremental lines only in
Major GAGs: hyaluronic acid, dermatan sulfate, chondratin
sulfate & keratan sulfate.
Play major regulatory roles during cementum mineralization
and are associated with initial phase of cementum formation.
BONE SIALOPROTEIN & OSTEOPONTIN:
Play a major role in filling spaces created during collagen
Regulators of hydroxyapitite crystal nucleation and growth.
Role in differentiation of cementoblast progenitor cells to
9. Osteopontin regulates cell migration, differentiation & survival.
Sialoprotein modulates the process of cementogenesis & is
involved in the process of chemo attraction, adhesion &
differentiation of precementoblasts.
Play imp role in skeletal mineralization.
Regulate tissue turnover & cell proliferation, differentiation,
Major function: hydrolysis of inorganic pyrophosphate, a
potent inhibitor of hydroxyapitite formation.
Plays key biological role in the mineralization of bone &
10. CEMENTUM- SPECIFIC PROTEINS:
CEMENTUM- DERIVED GROWTH FACTOR:
Insulin- like growth factor-1 like molecule.
Repair or regulate tissues.
Ability of cell migration, adhesion, mitogenic activity &
differentiation, essential for periodontal regeneration.
Cementum has the potential to regulate the metabolism & turn
over of surrounding tissues because of this growth factor.
CEMENTUM ATTACHMENT PROTEIN (CAP):
Promotes the attachment of gingival ﬁbroblasts, endothelial
cells & smooth muscle cells, but not oral sulcular epithelial cells .
Capacity to direct cell migration of alveolar bone cells.
Binds selectively to periodontal ligament cells and supports
periodontal ligament cell attachment to root surfaces.
11. CEMENTUM PROTEIN-I :
Synthesized by Hertwig’s epithelial root sheath cells.
Play a role during the biomineralization process & is
required for the synthesis of needle- like shape crystals.
Present throughout the entire cementum surface, including
the cementoid phase of acellular & cellular cementum,
cementocytes & cells near blood vessels in the PDL.
Associated with the regulation of sialoprotein expression in
12. ENAMEL- ASSOCIATED PROTEINS IN CEMENTUM:
Synthesized by Hertwig’s epithelial root sheath cells.
Results in the formation of a cellular- like tissue or bone
with the characteristics of cellular intrinsic fiber cementum.
Functions: promotion of cell proliferation, differentiation &
up-regulation of extracellular matrix production.
Involved in root formation.
Mainly secreted by osteoblasts (Gage et al; 1989).
Important for mineralization process.
Found in the PDL.
Also k/as bone Gla protein as it contains -carboxyglutamic
acid (Gla) residues.
Mainly secreted by osteoblasts (Mariotti, 1993), regulate
mineralization process, prevent hypercalcification of the
14. INORGANIC CONTENT
Calcium & phosphate in the form of hydroxyapitite.
Trace elements like Copper, Fluorine, Iron, Lead,
Potassium, Silica, Sodium and Zinc in varying amounts.
Cementum has the highest fluoride content.
a) BASED ON LOCATION
found on the root surface forms on the enamel
covering the crown
Coronal cementumRadicular cementum
16. b) PRESENCE/ ABSENCE OF CELLS
ACELLULAR CEMENTUM CELLULAR CEMENTUM
1) Present on the cervical third or half of
Present mainly on apical third of root.
2) Does not contain cells. Contain cells called cementocytes in
individual spaces lacunae.
3) Formed before the tooth reaches the
Formed after the tooth reaches the
4) More calcified Less calcified.
5) Sharpey’s fibers are main component
which inserted at approximately right
angles onto the root surface.
Sharpey’s fibers occupy smaller portion &
occupy other fibers that are arranged
parallel to the root surface.
6) Rate of development is faster . Slow .
7) Incremental lines are wide apart. Closer.
17. C) ORIGIN OF MATRIX FIBERS
EXTRINSIC FIBERS INTRINSIC FIBERS
1. Derived from PDL Derived from cementum.
2. Formed by fibroblast. Formed by cementoblast.
3. Run in same direction of the
PDL principal fibers i.e.
perpendicular or oblique to the root
Run parallel to the root surface
and at right angles to the extrinsic
18. d) PRESENCE OF COLLAGEN FIBRILS
FIBRILLAR CEMENTUM: Cementum with a matrix that
contains well-defined fibrils of type I collagen.
AFIBRILLAR CEMENTUM: Cementum that has a matrix
devoid of detectable type I collagen fibrils. Instead, the
matrix tends to have a fine, granular consistency.
19. e) SCHROEDER CLASSIFICATION (1986)
1. ACELLULAR AFIBRILLAR CEMENTUM (AAC):
Consists of mineralized matrix.
Contains neither cells nor fibers.
Doesn’t have any function in tooth attachment.
Formed by cementoblasts.
Found in coronal cementum.
Thickness : 1-15 µm.
2. ACELLULAR EXTRINSIC FIBER CEMENTUM (AEFC):
Confined to coronal half of the root .
Formed by fibroblast & cementoblasts.
Thickness- 30-230 µm.
Composed of densely packed bundles of sharpey’s fibers &
Only type of cementum seen in single rooted teeth.
20. 3. CELLULAR MIXED STRATIFIED CEMENTUM (CMSC):
composed of extrinsic (sharpey’s ) & intrinsic fibers &
Co- product of fibroblasts & cementoblasts.
appears in apical 3rd of roots, apices & furcation areas.
Thickness- 100-1000 µm.
4. CELLULAR INTRINSIC FIBER CEMENTUM (CIFC):
Contains cells & intrinsic collagen fibers.
Formed by cementoblasts & fills the resorption lacunae.
Very minor role in attachment.
Seen in middle to apical 3rd & inter radicular cementum.
21. 5. HYALINE LAYER OF HOPEWELL-SMITH
First layer of cementum is actually formed by the inner cells
of the HERS and is deposited on the root’s surface.
Deposition occurs before the HERS disintegrates.
situated between the granular dentin layer of Tomes and
the secondary cementum that is formed by the
10 m thick.
22. CELLS OF CEMENTUM
CEMENTOBLASTS CEMENTOCYTES CEMENTOCLASTS
Originate from the
in the dental follicle
Spider like cells
Lie in lacunae. Mononuclear cells,
found on the surface of
mitochondria, a well-
defined golgi apparatus
& large amounts of
Cytoplasmic vol &
density of cytoplasmic
organelles is reduced
when compared to
Role- Resorption &
24. CEMENTODENTINAL JUNCTION
• The cementum is attached to the dentin firmly
• CDJ is scalloped in deciduous teeth and is smooth in
• Sometimes cementum and dentin is separated by an
• Width appears to be stable even as age increases.
• About 2-3 µm wide.
25. INCREMENTAL LINES OF CEMENTUM
Referred to as “ Incremental lines of Salter”.
Represent rhythmatic periodic deposition of cementum.
Appear as dark lines running llel to root surface .
Seen in both acellular & cellular cementum but more
prominent in acellular cementum.
Highly mineralised areas with less collagen & ground
27. CEMENTAL RESORPTION
Permanent teeth don't undergo physiologic resorption as
do primary teeth.
Cementum resorption appears microscopically as bay like
concavities in the root surface.
The resorptive process may extend into the underlying
dentin & even into the pulp, but is usually painless.
Cementum resorption is not necessarily continuous & may
alternate with periods of repair & deposition of new
The newly formed cementum is demarcated from the root
by a deep staining irregular line, termed as reversal line.
trauma from occlusion
pressure from malaligned
Process to heal the damage caused by resorption of
Requires the presence of viable connective tissue.
Generally occur when the degree of
destruction is low.
Occurs in cases of large cemental
resorption or destruction.
The root outline is re-establised as it
was before cemental resorption.
To maintain the width of periodontal
ligament, the adjacent alveolar bone
grows and takes the shape of defect
following the root surface. This is
done to improve the function of
29. NORMAL FEATURES OF CEMENTUM
Extensive variation in surface topography of cementum
can be observed with scanning electron microscope
Resting cemental surfaces, where mineralization is more
or less complete, exhibit low rounded projections k/as
Cemental surfaces with actively mineralizing fronts have
numerous small openings.
Represent unmineralized cores of openings.
30. CEMENTUM IN PERIODONTAL DISEASE
Hurzeler & Zander: cementum apposition is less in
periodontally involved teeth than in normal teeth.
Cementum apposition decreases with advancing age in
periodontally involved teeth.
Gottlieb: areas of cemental resorption are frequently
31. ROOT SURFACE WALL OF PERIODONTAL
In normal cementum, the collagen fibers are embedded in the
These fibers are destroyed in pathological pocket wall with the
exposure of cementum.
Collagen remnants of Sharpey’s fibers in cementum undergo
degeneration creating a environment favorable for penetration
The mineral content of exposed cementum increases.
32. CHANGES AFTER INSTRUMENTATION
Firm scaling strokes used to remove sub gingival calculus,
also remove a small amount of cementum resulting in some
notching of root.
Cementum exposed by apical migration of junctional
epithelium is altered by exposure to sub gingival plaque
within the pocket.
May become hyper mineralized, demineralized or necrotic.
33. Lopez et al, 1980 necessary to remove all the diseased
cementum exposed to the pocket to eliminate its potential
for inducing inflammation.
Nyman et al, 1986 intentional root cementum removal is not
necessary for optimal postoperative healing.
Removal of cementum during root planing process has been
questioned due to possible sequelae of root sensitivity.
Also, it is thought that cementum removal is not necessary
to remove endotoxin because it is only weakly adherent to
cementum. (Wilson & Kieser; 1988, Hughes & Smales,
1986, Smart, Wilson, Daves & Kieser, 1990)
34. AGE CHANGES IN CEMENTUM
Smooth surface becomes irregular.
Continuous deposition of cementum occurs with age in
the apical area.
Cementum resorption active for a period of time and then
stops for cementum deposition creating - reversal lines.
Resorption of root dentin occurs with aging which is
covered by Cemental repair.
35. ANOMALIES IN CEMENTUM
Form of fusion which occurs after the root formation has
Here the teeth are united by cementum only, as a result of
traumatic injury or crowding of teeth with resumption of
the interdental bone so that the two roots are in
approximate contact and become fused by deposition of
cementum between them.
Concresence can occur before or after teeth have erupted
and usually involves two teeth.
36. 2. CEMENTICLES
Globular masses of cellular cementum less than 0.05mm in
diameter which form within the periodontal ligament.
May lie free within the periodontal ligament(free
cementicles) or become fused to the radicular cemental
surface(sessile or attached cementicles).
Originate from degenerating cells or epithelial cell rests in
the periodontal ligament.
37. 3.HYPERCEMENTOSIS (hyperplastic cementum)
Abnormal thickening of cementum.
May affect all teeth of the dentition, be confined to a single
tooth or even effect only parts of one teeth.
Localized hypercementosis may sometimes be observed in
areas in which enamel drops have developed on the dentin.
Such knob like projections are designated as excemetosis.
The thickening of cementum is often observed on teeth that
are not in function.
38. 4. ANKYLOSIS
• Fusion of cementum and alveolar bone with obliteration
of periodontal ligament
• It occurs due to:-
1) Cemental resorption
2) Chronic periapical inflammation
3) Tooth replantation
4) Occlusal trauma
39. 5. CEMENTAL TEARS
Detachment of a fragment of cementum from the root
Separation of cementum, may be complete with
displacement of a fragment into the periodontal ligament or
it may be incomplete with cementum fragment partially
attached to the roots.
Detached cementum, may be reunited to the root surface by
new cementum or may be completely resorbed or may
undergo partial resorption followed by addition of new
40. CLINICAL CORRELATION
Cellular cementum is similar to bone but has no nerves.
Therefore it is non-sensitive to pain. Scaling produces no
pain, but if cementum is removed, dentin is exposed causes
Cementum is resistant to resorption especially in younger
patients. Thus, orthodontic tooth movement causes
alveolar bone resorption and not tooth root loss .
Carranza’s clinical periodontology 10th ed.
Orbans oral histology and embryology. 12th edition.
Listgarten 1st ed.
International Journal of Scientific & Engineering Research, Volume 4,
Issue 12, December-2013.
The Cementum: Its Role In Periodontal Health and Disease: JOP, 1961.
Dental cementum reviewed: development, structure, composition,
regeneration and potential functions: Braz J Oral Sci. January/March
2005 - Vol.4 - Number 12.
Development and general structure of the periodontium:
Periodontology 2000, Vol. 24, 2000, 9–27.
Cementum proteins: role in cementogenesis,biomineralization,
periodontium formation and regeneration. Periodontology 2000, Vol.
Notes de l'éditeur
Cementum formation occurs along the entire tooth.
Hers- proliferation of ep cells located at the cervical loop of the enamel organ in the developing tooth
Cementum consists of organic matter, inorg, and water. By vol, cementum contains 35% org materials, 45% inorg material & 20% water.
1.CONTAINS PROTEOGLYCANS. 2. because they are integral components of cell substraum attachment matrices and mediate attachment bw old and newly formed cementum. Because acellular cementum doesnot contains proteoglycans.3. because hers cells express this proteoglycans during root development
2..non collagenous proteins. Osteopontin is present within the pdl in mature teeth. Bone sialoprotein: bsp2 Phosphoglycoprotein containing up to 20% of sialic acid residues (Bilezikian et all 1996). Osteopontin: bsp1 1st identified in osteoblasts in 1986.
Chemoattraction : unidirectional movement of a cell, in response to a chemical gradient of ligands……
alkaline phosphate:. Tissue non-specific alkaline phosphatase. Membrane bound glycoprotein enzyme. Expresses in most body sites during embryonic development but is confined to bone, kidney, liver & b- lymphocytes during adult lyf. Highly expresses in cells of pdl where they play role in phosphate metabolism n cementum formation particularly formatn of acellular cementum.
2.Mineralized tissues such as bone and dentin, are excellent reservoirs of growth factors.
Cap: collagenous cementum derived protein , promote the adhesion and spreading of mesenchymal cell types, with osteoblasts & pdl fibroblasts showing better adhesion than gingival fibroblasts & keratinocytes. Cap play role in the cell selection process. Play regulatory role during cementum formation. Imp role in promoting the differentiation of putative cementoblast progenitors.
osteonectin: Composed of a single polypeptide chain and has a strong affinity for calcium ions (Sage and Borstein, 1991) particularly strongly around the Sharpey’s fibers, at the attachment sites between the ligament, alveolar bone and the cementum……..
Osteocalcin: localised in cells lining cellular n acellular cementum. Also present in interradicular cells.
The area where both extrinsic and intrinsic fibers is called mixed fiber cementum
1. Provides medium for attachment to the collagen fibers of the PDL.
2. Cementum is harder than alveolar bone & is avascular & doesn't show resorption under masticatory or orthodontic forces.
3. Covers the root surface, forms seal for open dentinal tubules.
4, Property of continuous deposition thus it repairs the damage such as fracture or resorption of root surface.
5. Aid in maintaining the teeth in functional occlusion if deposited at apical aspect especially in patients with chronic bruxism- passive eruption.
CHANGES IN DISEASED CEMENTUM: Many Gram –ve bacteria have the ability to attach to Gram +ve bacteria in the cementum & epithelial cells (Slots & Genco, 1984).