this powerpoint presentation contains important knowledge on cementum, that is a part of periodontium. it also includes the clinical aspects related to cementum. this presentation basically for the post graduation level.

2. CEMENTUM
NIDHI PANDEY
PG 1ST YR

3. CONTENT
• Introduction
• History
• Definition
• Development
• Physical characteristics
• Biochemical composition
• Incremental lines
• Classification of cementum
• Junctions
– CDJ
– CEJ
• Functions
• Resorption & repair
• Age changes
• Abnormalities of cementum
• Applied aspects
• Conclusion
• References

4. INTRODUCTION
• Cementum is a mineralized
dental tissue covering the
anatomic root of teeth.
• It begins at the cervical portion
of the tooth at CEJ and
continues to the apex.
• Cementum furnishes a medium
for the attachment of collagen
fibers that bind the tooth to
surrounding structures.

5. HISTORY
• This tissue was not discovered and characterized on
human teeth until a full century later than enamel
and dentin.
• First detailed descriptions of human cementum was
in the 1830s by Jan Purkinje and Anders Retzius, who
identified for the first time acellular and cellular types
of cementum, and the resident cementocytes
embedded in the latter.

6. The functional importance of cementum was not
appreciated until detailed anatomical studies of the
periodontium were performed by G.V. Black and
others in the late nineteenth and early twentieth
centuries.

7. DEFINITION
• It is a specialized connective tissue that shares some
physical, chemical and structural characteristics with
compact bone.
-Orban’s oral histology
• Cementum is the calcified, avascular mesenchymal
tissue that forms the outer covering of the anatomic
root.
-Carranza 13th edition

8. • Cementum is an avascular mineralized
mesenchymal tissue covering the entire root
surface.
- Periobasics

9. DEVELOPMENT

10. PHYSICAL CHARACTERISTICS
• Hardness- less than cementum.
• Color- -light yellow in color.
-lighter than dentin.
-distinguished from enamel by its lack of
luster and darker hue.
• Thickness- varies in different teeth and in same teeth
in different regions.
-thinnest at CEJ (20-50um)
-thickest towards apex (150-200um)

11. • It is thicker in distal surfaces than in mesial surfaces,
probably because of functional stimulation from mesial drift
over time.
• Between the ages of 11 and 70 years, the average thickness
of the cementum increases threefold, with the greatest
increase seen in the apical region. Average thicknesses of 95
µm at the age of 20 years and of 215 µm at the age of 60
years have been reported.
-Zander HA(1958)

12. • Permeability-
– In very young animals, acellular cementum and cellular
cementum are very permeable and permit the diffusion of
dyes from the pulp and the external root surface.
– In cellular cementum, the canaliculi in some areas are
contiguous with the dentinal tubuli. The permeability of
cementum diminishes with age.
– Blayney JR(1941)

13. CHEMICAL COMPOSITION
cementum
Organic
content
45-50%
Inorganic
content
50-55%

14. Inorganic content-
• Principal mineral components-
– Calcium
– Phosphate
• Crystallinity is less.
• Has the higher fluoride content of all the mineralized
tissues.
HYDROXYAPATITE

15. Organic content-
• Collagen fibers – type 1
type 3, 5, 6, 12
• 2 major Glycoproteins- BSP , Osteopontin
• Cementum Derived Attachment Proteins
• Proteoglyacans:- Chondroitin sulphate
Heparan sulphate
Hyluronatee
Keratan sulphate
Versican, biglycan
enhance the
proliferation
of gingival
fibroblasts and
periodontal
ligament cells

16. • Growth factors: TGF-beta ,
BMPs,
PDGF,
CEMENTUM DERIVED GROWTH
FACTORS

17. Classification of cementum
• Depending on the presence or absence of
cementocytes:
1. Acellular
2. Cellular
• Depending on the origin and nature of organic matrix:
1. Extrinsic fiber cementum
2. Intrinsic fiber cementum

18. • Depending upon the time of formation, presence or
absence of cells, and on the nature and origin of
organic matrix:
1. Primary acellular intrinsic fiber cementum
2. Primary acellular extrinsic fiber cementum
3. Secondary cellular intrinsic fiber cementum
4. Secondary cellular mixed fiber cementum
5. Acellular afibrillar cementum

20. INCREMENTAL LINES
• Lines of salter!
• Highly mineralized areas.
• These are closer in acellular
cementum but in cellular
cementum they are widely
displaced.
• Are of value in age estimation.

21. JUNCTIONS OF
CEMENTUM

22. Cementoenamel junction (CEJ)

23. Cementodentinal junction (CDJ)
• CDJ consist of a wide zone
containing large quantities of
collagen associated with
Glycosaminoglycans
• Increased water content
• Contributes to the stiffness

24. CDJ-
• Collagen fibrils of cementum
and dentine interwine at their
interface in a very complex
fashion;
It is not possible to precisely
determine that which fibers
are of dentinal or cemental
origin.

25. FUNCTIONS
• ANCHORAGE: PRIMARY FUNCTION
• ADAPTATION: KEEPING ATTACHMENT APPARATUS
INTACT
• REPAIR: MAJOR REPARATIVE TISSUE

26. Resorption & repair
• Physiologic resorption-
• Areas of cementum resorption se with age.
• Cementum resorption appears microscopically as
baylike concavities in the root surface.
Primary teeth
Permanent teeth

27. • Systemic diseases asso. With cementum resorption-
– Paget’s disease
– Herediatary fibrous osteodystrophy
– Hypothyroidism
– Calcium deficiency
inflammation
Mechanical
trauma
TFO
Orthodontic
tooth
movement
Periapical
pathology
Pressure from
mal aligned
erupting
tooth

28. Repair -
• Repair of cementum occurs by deposition of new
cementum. Easily identified by reversal lines.
• The cementoblasts depositing new cementum are
derived from the surrounding connective tissue,
mostly from PDL.
• Under specific conditions, the epithelial rest of
Malassez may play an active role in repair.
-Hasegawa N (2003)

29. Age changes
• Thickness ses.
• The thickness of cementum on the distal root surface
is more than on the mesial root surface.
• The increase in width is greater apically and lingually.
Although cementum has limited capacity for
remodelling, an accumulation of resorption bays
explains the inding of increasing surface
irregularity.

30. ABNORMALITIES OF CEMENTUM
• HYPERCEMENTOSIS-
– An abnormal thickening of cementum.
– May be diffuse, circumscribed.
– May affect all teeth or a single tooth or even only parts of
a tooth.

31. • ANKYLOSIS:-
– Fusion of cementum with alveolar bone with obliterated
PDL.
– Seen with hypercementosis.
– After inflammation, occlusal trauma.
• CEMENTAL TEARS:-
– Tear along one incremental line or CDJ.

32. CLINICAL CONSIDERATION
• Resistance to resorption orthodontic tooth
movement.
• Repair
1. Anatomical repair
2. Functional repair
• Pathologically exposed cementum

33. • Cementum In Periodontal Involvement:
– Breakdown of dentogingival fibers.
– Loss of collagen fibers cross banding
– Dissolution of inorganic content.(soften)
Constant saliva Hypercalcified area
Plaque accumulation hypocalcified area
• Bacterial endotoxins found in cemental depths.
Structural changes interfere with healing

34. Applied Aspect

35. CEMENTUM IN PERIODONTAL
REGENERATION

36. 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.

37. References
• Orban’s Oral histology and embryology – 12th edition
• Clinical periodontology by CARRANZA – 13th edition
• Biology of the periodontal connective tissues – P.
Mark Bartold
• Periobasics – Nitin Saroch
• Foster, B. L. (2017). On the discovery of cementum.
Journal of Periodontal Research, 52(4), 666–
685. doi:10.1111/jre.12444