A PRESNTATION ABOUT THE VARIOUS ASPECTS OF CEMENTUM.

1. CEMENTUM
DR.VIGNESH R, BDS

2. CONTENTS
■ UNIQUE FEATURES
■ PHYSICAL PROPERTIES
■ CHEMICAL PROPERTIES
■ CLASSIFICATION
■ EACH TYPE IN DETAIL
■ CEMENTOGENESIS
■ AGE CHANGES & FUNCTIONS

3. UNIQUE FEATURES
■ HARD AVASCULAR DENTAL TISSUE
■ COVERS ROOT PORTION OF TOOTH
■ FORMS A PART OF “PERIODONTIUM”
■ IS FORMED BY CEMENTOBLASTS JUST LIKE
ANY OTHER HARD TISSUE –
■ FIRST AS UNMINERALIZED ORGANIC MATRIX –
PRECEMENTUM
■ LATER GETS MINERALIZED TO MATURE CEMENTUM

5. UNIQUE FEATURES
FORMS ONE ANCHOR POINT FOR
PERIODONTAL LIGAMENT
(THE OTHER POINT IS ALVEOLAR BONE)
THE PDL ACTS LIKE A SLING ATTACHED
TO CEMENTUM & PERIODONTAL
LIGAMENT
THIS SUPPORTS THE TOOTH IN ITS
SOCKET.

6. PHYSICAL PROPERTIES
■ LESS MINERALIZED THAN ENAMEL &
DENTIN
■ HARDNESS LESS THAN ENAMEL &
DENTIN
■ DULL YELLOW IN COLOR
■ MORE PERMEABLE THAN DENTIN
■ MAXIMUM FLUORIDE CONTENT AMONG
ALL DENTAL TISSUES.

7. PHYSICAL PROPERTIES
❖ NORMALLY NOT VISIBLE CLINICALLY
❖ SURROUNDED BY ALVEOLAR BONE
IN TOOTH SOCKETS
❖ WHEN GINGIVA RECEDES, CEMENTUM
GETS EXPOSED
❖ IT READILY UNDERGOES ABRASION
❖ KEEPS FORMING IN LIFE (UNLIKE
ENAMEL)

8. PHYSICAL PROPERTIES
■ DOES NOT HAVE THE ABILITY TO
REMODEL (UNLIKE ALVEOLAR BONE)
■ MORE RESISTANT TO RESORPTION
THAN ALVEOLAR BONE
■ THESE PROPERTIES OF CEMENTUM
ARE MADE USE OF IN ORTHODONTIC
MOVEMENT OF TEETH.

9. CHEMICAL PROPERTIES
■ 45 - 50%  INORGANIC MATTER
■ 50 – 55%  ORGANIC MATTER + WATER
■ ORGANIC MATTER  TYPE I COLLAGEN
+ GROUND SUBSTANCE
■ INORGANIC MATTER – HYDROXYAPATITE
CRYSTALS + TRACE ELEMENTS.
■ FLUORIDE IONS

10. INCREMENTAL LINES
■ CEMENTUM DEPOSITED AS
INCREMENTS
■ RESULTS IN LINES IN ITS STRUCTURE
■ AT IRREGULAR INTERVALS
■ NOT FORMED UNIFORMLY
■ INCREMENTAL LINES OF SALTER.

13. CEMENTO-ENAMEL JUNCTION
(CEJ)
■ THE JUNCTION WHERE CEMENTUM
MEETS ENAMEL
■ ALSO CALLED CERVICAL LINE
■ NOT VISIBLE CLINICALLY
■ COVERED BY GINGIVA
■ THREE PATTERNS ARE POSSIBLE.

14. CEMENTO-ENAMEL JUNCTION
(CEJ)
■ IN 60% INDIVIDUALS,
CEMENTUM OVERLAPS
ENAMEL.
■ THIS IS CALLED OVERLAP
TYPE CEJ.

15. CEMENTO-ENAMEL JUNCTION
(CEJ)
■ IN 30% INDIVIDUALS, CEMENTUM
& ENAMEL MEET AT A SINGLE
POINT
■ WITHOUT OVERLAPPING
■ “EDGE-TO-EDGE” CEJ OR “BUTT”
TYPE CEJ

16. CEMENTO-ENAMEL JUNCTION
(CEJ)
■ IN 10% INDIVIDUALS, CEMENTUM &
ENAMEL DO NOT MEET AT ALL.
■ THIS LEAVES A GAP AT THE CEJ
■ EXPOSES THE UNDERLYING ROOT
DENTIN
■ DEFICIENCY OF CEMENTUM
FORMATION
■ GAP TYPE CEJ

17. CLASSIFICATION OF
CEMENTUM
■ BASED ON 3 CRITERIA:
PRESENCE OR ABSENCE OF
CELLS
ORIGIN AND NATURE OF
COLLAGEN FIBERS
COMBINATION OF BOTH THE
ABOVE.

18. PRESENCE OR ABSENCE OF
CELLS
■ CEMENTUM IS FORMED BY
CEMENTOBLASTS
■ AS THEY GROW OLD, THEY GET
ENTRAPPED IN THEIR OWN MATRIX
BECOME INACTIVE AND FLAT
■ KNOWN AS CEMENTOCYTES.
■ THESE ARE FOUND IN THE STRUCTURE
OF CEMENTUM

19. PRESENCE OR ABSENCE OF
CELLS
■ THAT TYPE OF CEMENTUM WHERE
CEMENTOCYTES ARE SEEN 
CELLULAR CEMENTUM
■ THAT TYPE WHERE THERE ARE NO
CEMENTOCYTES 
ACELLULAR CEMENTUM
CELLS ARE INCORPORATED IN THE
LATER FORMED CEMENTUM.

20. PRESENCE OR ABSENCE OF
CELLS
ACELLULAR C
NO CEMENTOCYTES
FORMS FIRST 
PRIMARY CEMENTUM
MAINLY ON CERVICAL
2/3 OF ROOTS
MAJOR ROLE IN
ATTACHEMENT
SLOW RATE OF
DEVELOPMENT
CELLULAR C
CEMENTOCYTES SEEN
FORMS LATER 
SECONDARY C
MAINLY ON APICAL 1/3,
OVER THE ACELLULAR
TYPE
MINOR ROLE IN
ATTACHMENT
FASTER RATE OF
FORMATION.

24. CEMENTOCYTES
CELLS SEEN IN STRUCTURE OF CEMENTUM
MOSTLY INACTIVE
ROUND / OVOID
PLACED IN EMPTY SPACES IN CEMENTUM
 LACUNAE
LONG CYTOPLASMIC PROCESSES RADIATE
FROM CELL BODY
PROCESSES PLACED IN CANALS 
CANALICULI.

26. CEMENTOCYTES
■ CEMENTUM  AVASCULAR
■ NO NUTRITION FOR CELLS IN
CEMENTUM
■ CANALICULI DIRECTED TO
PERIODONTAL LIGAMENT (SURFACE)
■ NEAREST SOURCE OF NUTRITION 
PDL.

27. ORIGIN & NATURE OF
COLLAGEN FIBERS
■ COLLAGEN FIBERS (ORGANIC MATRIX)
IN CEMENTUM DERIVED FROM 2
SOURCES:
■ NATIVE FIBERS  BY CEMENTOBLASTS
MAJORITY OF COLLAGEN FIBERS –
INTRINSIC FIBERS
■ INSERTED FIBERS FROM PERIODONTAL
LIGAMENT  SMALL GROUP –
EXTRINSIC FIBERS.

28. ORIGIN & NATURE OF
COLLAGEN FIBERS
INTRINSIC FIBER C
COLLAGEN FIBERS
DERIVED FROM
NATIVE
CEMENTOBLASTS
MAJOR SOURCE OF
COLLAGEN FIBERS
PARALLEL TO ROOT
SURFACE
EXTRINSIC FIBER C
COLLAGEN FIBERS
ARE INSERTED
FROM PDL
SMALL GROUP OF
FIBERS
OBLIQUE /
PERPENDICULAR
TO ROOT SURFACE.

29. ORIGIN & NATURE OF
COLLAGEN FIBERS
IN CERTAIN AREAS OF THE ROOT, THE
INTRINSIC COLLAGEN FIBERS MIX WITH
THE INSERTING EXTRINSIC FIBERS.
THE CEMENTUM IN THESE AREAS IS
ALSO CALLED
“MIXED FIBER CEMENTUM”

30. COMBINATION OF BOTH THE
ABOVE CRITERIA
ACELLULAR EXTRINSIC FIBER
CEMENTUM (AEFC)
CELLULAR INTRINSIC FIBER
CEMENTUM (CIFC)

31. A E F C
❖ NO CEMENTOCYTES
❖ FORMS FIRST  PRIMARY CEMENTUM
❖ MAINLY ON CERVICAL 2/3 OF ROOTS
❖ COLLAGEN FIBERS ARE INSERTED
FROM PDL
❖ SMALL GROUP OF FIBERS
❖ OBLIQUE / PERPENDICULAR TO ROOT
SURFACE.

32. C I F C
✓ CEMENTOCYTES SEEN
✓ FORMS LATER  SECONDARY C
✓ MAINLY ON APICAL 1/3, OVER THE
ACELLULAR TYPE
✓ COLLAGEN FIBERS DERIVED FROM NATIVE
CEMENTOBLASTS
✓ MAJOR SOURCE OF COLLAGEN FIBERS
✓ PARALLEL TO ROOT SURFACE

33. ACELLULAR AFIBRILLAR
CEMENTUM
ACELLULAR – NO CEMENTOCYTES
AFIBRILLAR – NO MATURE COLLAGEN
FIBERS
ONLY DELICATE FIBRILS IN THE ORGANIC MATRIX.
LACK OF MATURE COLLAGEN FIBERS
 NO ROLE IN TOOTH ATTACHMENT.

34. INTERMEDIATE
CEMENTUM
???????

35. FUNCTIONS OF CEMENTUM
❑SUPPORTIVE (ATTACHMENT)
❑ANCHORAGE
❑ORTHODONTIC TOOTH
MOVEMENT
❑REPAIR

36. CLINICAL ASPECTS
■ HYPERCEMENTOSIS
■ EXCESS DEPOSITION OF CEMENTUM ON ROOT
SURFACE (GENERAL / LOCAL)
■ CEMENTICLES
■ CONCENTRIC MASSES OF CEMENTUM IN PDL
■ CEMENTAL TEARS
■ FRAGMENTS OF CEMENTUM IN PDL
■ ABSENCE OF CEMENTUM