1. PRESENTED BY:
SONAL GOYAL
1ST YR. P.G. STUDENT
DEPARTMENT OF
PERIODONTOLOGY
DENTAL CEMENTUM: THE
DYNAMIC TISSUE
COVERING OF THE ROOT

2. CONTENTS:
1. Introduction
2. Definition
3. History
4. Properties
- Physical properties
- Chemical properties
5. Composition
- Organic matrix
- Inorganic matrix
6. Cementogenesis
1.Cementoblasts
2.Cementocytes
3.Stages of development

3. 4. Cemento-dentinal junction
5. Mineralization
7.Classification
8. Cementoenamel Junction
9.Age changes
10.Resorption and Repair
11.Periodontal pathology
12.Diseases
13.Conclusion
14.References

4. INTRODUCTION
Cementum is an avascular mineralized tissue covering the entire root
surface. Due to its intermediary position, forming the interface between
root dentin and periodontal ligament, cementum is a component of the
tooth itself, but belongs functionally to the dental attachment apparatus,
that is, the periodontium.
Gonçalves PF, Sallum EA, Sallum AW et al. Dental cementum reviewed: Development,
structure, composition, regeneration and potential functions. Braz J Oral Sci. January/March
2005 ;4: 651-658

5. Dental cementum is unique in various aspects: it does not undergo
continuous remodeling like bone, but continues to grow in thickness
throughout life.
Gonçalves PF, Sallum EA, Sallum AW et al. Dental cementum reviewed: Development,
structure, composition, regeneration and potential functions. Braz J Oral Sci. January/March
2005 ;4: 651-658

6. Unlike dentin and enamel, where there are clear differences in the
proteins present in these tissues and the factors regulating their
functions when compared with bone, cementum has not demonstrated
to express specific proteins, appearing to contain factors in common
with bone and to be developmentally controlled by similar factors.
Gonçalves PF, Sallum EA, Sallum AW et al. Dental cementum reviewed: Development,
structure, composition, regeneration and potential functions. Braz J Oral Sci. January/March
2005 ;4: 651-658

7. DEFINITION
Cementum is the calcified, avascular mesenchymal tissue that forms
the outer covering of the anatomic root.

8. HISTORY
According to Denton, cementum was first demonstrated microscopically
by
Fraenkel and Raschkow (1835)
Retzius (1836)
Yamamoto T, Hasegawa T, Yamamoto T et al. Histology of human cementum: Its structure,
function, and development. Japanese Dental Science Review 2016 ;52: 63-74

9. PROPERTIES
Physical properties:-
• Pale yellow with dull surface.
• Softer than dentine.
• Permeability varies with age and the type of cementum, the cellular
varieties being more permeable.
• Readily removed by abrasion owing to relative softness and thinness
cervically.
Tencate R. Periodontium. In : Textbook of Oral Histology. 8. Elsevier; 2015: 205-232.

10. Chemical properties:-
• Wet weight basis- 65% inorganic material, 23% organic material, 12%
water.
• By volume- 45% inorganic material, 33% organic material, 22%
water.
• The degree of mineralization varies in different part of the tissues.
• The principal component is hydroxyapatite crystals, approx. 55 nm
wide and 8 nm thick..
• The collagen is virtually all Type-I collagen.
Tencate R. Periodontium. In : Textbook of Oral Histology. 8. Elsevier; 2015: 205-232.

11. COMPOSITION
Since cementum is not a uniform, mineralized
connective tissue, differences in the proportional
composition of the chemical constituents exist
between the various cementum varieties.
Biochemical studies have shown that “cementum” has
a chemical composition similar to bone.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

12. To about equal parts per volume, cementum is
composed of water, organic matrix and minerals.
About 50% of the dry mass is inorganic, and consists
of hydroxyapatite crystals.
The remaining organic matrix contains largely
collagens, glycoproteins, and proteoglycans.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

13. 1.ORGANIC MATRIX
 Collagens:
a) The organic matrix of cementum consists primarily of collagens.
b) The two typical fibril-forming collagens Type I (90%) and Type III
(5%) are found in cementum.
c) Type- XII, a fibril-associated collagen with interrupted triple helices,
binds to Type- I collagen and also to noncollagenous matrix proteins.
d) Trace amounts of Type V, VI, XIV, are also found.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

14. • Plays structural as well as morphogenic roles.
• Provides scaffolding for mineral crystals.
Type-I
collagen
• Coats type-I collagen fibrils.
• Less cross-linked collagen
• High concentration during development and
repair/ regeneration.
Type-III
collagen
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

15.  The procollagen molecules are secreted and aggregate extracellularly
to form cross-striated collagen fibrils with the typical 67 nm banding
pattern.
 This striking banding pattern stands out in electron micrographs and is
partly obscured when the collagenous matrix is mineralized.
 Frequently observed in membrane bound compartments within the
cementoblasts cytoplasm.
 These serve to position newly produced fibril segments to already
existing fibril bundles.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

16.  Non-collagenous proteins:
1.Cementum is rich in glycoconjugates :-
 glycolipids
 glycoproteins
 proteoglycans.
2. Non-collagenous proteins found in cementum are :-
 bone sialoprotein
 Dentin matrix protein-1
 Dentin sialoprotein
 fibronectin
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

17.  Osteocalcin
 Osteonectin
 Tenascin
 Proteolipids
 Growth factors- cementum growth factors
 Enamel proteins- amelogenins
 Cementum attachment protein.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

18. Tencate R. Periodontium. In : Textbook of Oral Histology. 8. Elsevier; 2015: 205-232.

19. Tencate R. Periodontium. In : Textbook of Oral Histology. 8. Elsevier; 2015: 205-232.

20. Tencate R. Periodontium. In : Textbook of Oral Histology. 8. Elsevier; 2015: 205-232.

21.  Bone Sialoprotein and Osteopontin :-
1. Phosphorylated and sulfated glycoprotein.
2. Binds tightly to the collagenous matrices and hydroxyapatite.
3. Participates in the mineralization process
4. Reveals cell attachment properties through the tripeptide sequence
(Arg-Gly-Asp)
5. Acellular afibrillar cementum and acellular extrinsic fiber cementum.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

22. 2. INORGANIC MATRIX
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75
 Cementum is less mineralized than root dentin.
 Acellular extrinsic fibre cementum appears more mineralized than
cellular intrinsic fibre cementum and cellular mixed stratified
cementum.
 Chemical and physio-chemical studies indicate that the mineral
component is the same as in the other calcified tissues, ie.
Hydroxyapatite (Ca10(PO4)6(OH)2) with small amounts of
amorphous calcium phosphates.

23.  Transmission electron microscopy and electron diffraction analyses
have confirmed that the mineral crystals are arranged with their
crystallographic c-axis parallel to the long axis of the collagen fibril
with which they are associated.
 Contains 0.5%-0.9% magnesium ions, and almost equal amount of
calcium ions.
 Up to 0.9% ash weight fluoride content.
 0.1-0.3% Sulphur.
 Trace elements- Cu, Zn, Na.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

24. CEMENTOGENESIS
1.Cementoblasts:-
• Studies have shown a possibility that acellular and cellular
cementum have different developmental origin.
• Derived from dental follicle which is of ectomesenchymal origin.
or
• Recent ultrastructural and immunohistochemical studies have shown
that the cementoblasts originate from the epithelial cells of HERS
when they undergo an epithelial-mesenchymal transformation.
• HERS is actively involved in the formation of both types of
cementum.

25. cementoblasts

26.  Gottlieb indicated that HERS was removed from the root surface prior
to cementum deposition.
 Insitu hybridization and immunolocalization data reveals amelogenin
mRNA and enamel proteins were restricted to the crown enamel and
were absent from root surface
 Western blot tests showed cementum protein extracts did not cross
react with amelogenin antibodies.
Cementum is a dental follicle derived connective tissue that forms
subsequent to HERS disintegration.
Gonçalves PF, Sallum EA, Sallum AW et al. Dental cementum reviewed: Development,
structure, composition, regeneration and potential functions. Braz J Oral Sci. January/March
2005 ;4: 651-658

27.  The differentiation of cementoblasts from cementoprogenitor cells and
the formation of the dentinocemental junction are temporally and
spatially closely related to dentin formation.
 The initiation of cementogenesis is, therefore, restricted to a narrow
band (200-300 µm) encircling the forming root at its most apical
portion.
 This circular band extends coronally from the advancing root edge
and shifts in the apical direction while the root elongates.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

28. 2.CEMENTOCYTES:-
 Cementocytes are similar in morphology
to osteocytes.
 Numerous cell processes radiate outward
from the central cell body. The cell body
resides in the lacuna, while the
cytoplasmic extensions reside in the
canaliculi.
 In living cementocytes, the canaliculi
containing the cell processes are oriented
towards the PDL, i.e., toward the source
of nutrition.

29.  Since all cementum is avascular, the buried (deeper) cementocytes of
cellular cementum are totally dependent upon the diffusion of
nutrients from the vessels within the PDL.
 Cementocytes in deeper layers are characterized by a reduction in
cytoplasmic organelles & by a concomitant increase in inactive
nuclear chromatin (heterochromatin), indicating degeneration/
marginal activity of cells.
 At a depth of 60µm/ more, cementocytes show definite signs of
degeneration such as cytoplasmic clumping & vesiculation.
 The lacunae in the deeper layers appear to be empty at the light
microscopic level, suggesting complete degeneration of cells.

30. 3.STAGES OF DEVELOPMENT
Prefunctional
stage Functional
stage
Tencate R. Periodontium. In : Textbook of Oral Histology. 8. Elsevier; 2015: 205-232.

31. Formed during root
development. Extends over a
period of 3.75-7.75 years(root
formation). Primary distribution
of the main cementum is
determined for each root.
Commences when the tooth is
about to reach the occlusal
level. Adaptive and reparative
processes carried out by
biological responsiveness of
cementum.
Pre-functional stage
Functional stage

32.  Diekwisch in 2001 described cementogenesis as :-
Deposition of dentin along the inner aspect of
HERS.
Hertwigs epithelial root sheath disintegrates
Dental follicle cells penetrate the epithelial
layer.
Invades the root surface.
Gonçalves PF, Sallum EA, Sallum AW et al. Dental cementum reviewed: Development,
structure, composition, regeneration and potential functions. Braz J Oral Sci. January/March
2005 ;4: 651-658

33. Newly formed dentin comes in contact with
the cells of the dental follicle.
Differentiation of cementoblasts along the
external surface of root
Protein secretion by cementoblasts
Mainly collagen and proteoglycans which
forms the organic matrix of cementum
Matrix maturation and mineralization.

34. Initial cementum formation. The
first increment of cementum forms
against the root dentin surface.
Epithelial cell rests of Malassez
(remnants of the root sheath) can be
seen within the follicular tissue.
Cell rests of Malassez
Periodontal ligament
dentin
cementum

36. • HERS disintegrates into small clusters or strands of epithelial
cells.
• Undergo epithelial/ mesenchymal transformation into
fibroblasts and cementoblasts, deposit acellular and cellular
cementum respectively.
• Becomes incorporated into cellular cementum.
• Trapped between cementum and dentin during formation of
the apical part of the root.
Gonçalves PF, Sallum EA, Sallum AW et al. Dental cementum reviewed: Development,
structure, composition, regeneration and potential functions. Braz J Oral Sci. January/March
2005 ;4: 651-658

37. • The only incontrovertible fact is, they retain
epithelial phenotype and survive in PDL as epithelial
rests of Malassez.
Gonçalves PF, Sallum EA, Sallum AW et al. Dental cementum reviewed: Development,
structure, composition, regeneration and potential functions. Braz J Oral Sci. January/March
2005 ;4: 651-658

38. 4.CEMENTO-DENTINAL JUNCTION
The terminal apical area of
cementum where it joins the
internal root dentin is called
cementodentinal junction or
CDJ.
Width of CDJ is 2 to 3µm and
remains relatively stable.
Scalloped in deciduous teeth &
smooth in the permanent teeth.

39. Cementoprogenitor cells differentiate along the newly deposited and
not yet mineralized matrix of the radicular mantle dentin into
cementoblasts.
At the beginning of their maturation on the root surface, they extend
numerous tiny cytoplasmic processes into the loosely arranged and
not yet mineralized dentinal matrix.
This enables the cementoblasts to position the initially secreted
collagen fibrils of the cementum matrix among those of the dentinal
matrix.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

40. This leads eventually to an intimate
interdigitation of the two different fibril
populations.
The mineralization of the outermost layer of
the dentin matrix, (mantle dentin) appears to
be delayed.
Mineralization front in dentin reach the future
dentinocemental junction, not before the
implantation of the cementum matrix is
established and the dentinal matrix is
completely covered with the collagen fibrils of
cementum.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

41. 5. MINERALIZATION
 Begins in the depth of the precementum.
 Fine hydroxyapatite crystals are deposited
1. Between the collagen fibrils.
2. Within the collagen fibrils.
 According to Zander and Hurzeler, the mean linear rate of cementum
deposition on single rooted tooth is about 3μm per year.
 The width of precementum layer is 3-5 μm.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

42.  Sharpey’s fibres
 Sharpey’s fibres are collagen fibres embedded into cementum on one
side and into the alveolar bone on another.
 Numerous but smaller at their attachment into cementum than bone.
 Mineralization is at right angle to the long axis of the fibres- in
function, the fibres are subjected to tensional forces.
 In primary acellular cementum- fully mineralized.
 In cellular cementum- mineralized partially at periphery.

45. CLASSIFICATION
1. Based on time of formation (B.Gottlieb JP, 1942)
Primary cementum Secondary cementum
• Formed before eruption and
prior to teeth reaching functional
occlusion.
• Devoid of cells
• Contains randomly oriented
collagen fibrils embedded in a
granular matrix.
• Subsequent to occlusal contact.
• Contains cells
• Coarse collagen fibrils oriented
parallel to root surface and
Sharpey’s fibers perpendicular
to root surface.
Tencate R. Periodontium. In : Textbook of Oral Histology. 8. Elsevier; 2015: 205-232.

46.  2.Based on presence or absence of cells (B.Gottlieb, 1942)

47. 3. Based on location of tooth :-
Coronal cementum Radicular cementum
4. Based on origin of fibers (Selvig,1965) :-
Intrinsic fibers Extrinsic fibres

48. 5. Based on location, structure, function, rate of formation,
biochemical composition and degree of mineralization
cementum can be classified as(Schroeder,1992):
 Acellular Afibrillar Cementum
 Acellular Extrinsic Fiber Cementum.
 Cellular Mixed Stratified Cementum.
 Cellular Intrinsic Fiber Cementum.
 Intermediate cementum

49. Consist of mineralized matrix.
This matrix appears similar to interfibrillar
matrix of acellular extrinsic fibre cementum.
Contains neither collagen fibrils nor
embedded cells.
It has no function in tooth attachment.( lack
of collagen fibrils).
1. Acellular Afibrillar Cementum

50. Light microscopy Electron microscopy
•Stands out by basophilia.
•More or less uniform appearance.
•Less homogeneous appearance.
•Multifarious appearance- a
variable number of layers with
varying electron density and
different texture, can either be
granular or reticular.

51.  Its formation commences at the end of enamel maturation and
continues for an unknown period of time.
 Found as isolated patches or as the most cervical part of AEFC on
enamel just coronal to CEJ.
 3 theories of formation have been proposed :-
1. Connective tissue cells produce AAC, if this is true connective tissue
cells must replace REE.
2. AAC is an epithelial product, deposited by inner enamel epithelial
cells which are about to become HERS.
3. AAC is a mere precipitate derived from tissue fluid or serum.
Yamamoto T, Hasegawa T, Yamamoto T et al. Histology of human cementum: Its structure,
function, and development. Japanese Dental Science Review 2016 ;52: 63-74

52. 2. ACELLULAR EXTRINSIC FIBRE
CEMENTUM

53.  Covers upto 60-90% of the root length in single rooted tooth and
cervical half to one-third in multirooted tooth.
 With age, thickness increases upto 50-200 µm.
 Its formation commences shortly after crown formation is completed
and always before cellular intrinsic fibre cementum starts to form on
more apical root portions.
 Produced by cementoblasts which commence their differentiation in
closest proximity to advancing root edge.
 Contains collagen fibres and noncollagenous proteins as organic
matrices, both fully mineralized.
Yamamoto T, Hasegawa T, Yamamoto T et al. Histology of human cementum: Its structure,
function, and development. Japanese Dental Science Review 2016 ;52: 63-74

54.  Collagen fibres :-
 Belong to extrinsic fibres group.
 Densely packed and arranged nearly perpendicular to root surfaces.
 Diameter- approx. 3-6 µm.
 Shows branching and anatomising.
 These fibres are implanted into the dentinal matrix.
 The extrinsic fibres remain short until the tooth is about to reach the
occlusal level.
 AEFC functions in anchorage to the surrounding bone.
Yamamoto T, Hasegawa T, Yamamoto T et al. Histology of human cementum: Its structure,
function, and development. Japanese Dental Science Review 2016 ;52: 63-74

55. INCREMENTAL LINES OF SALTER
•Also known as resting line, formed
during intermediate AEFC formation.
•Highly mineralized.
•These lines represent the periodic
deposition of the cementum layers in
frequent association with an abrupt
change in the direction of sharpey’s
fibres.
Yamamoto T, Hasegawa T, Yamamoto T et al. Histology of human cementum: Its structure,
function, and development. Japanese Dental Science Review 2016 ;52: 63-74

56. 3. CELLULAR MIXED STRATIFIED CEMENTUM
Yamamoto T, Hasegawa T, Yamamoto T et al. Histology of human cementum: Its structure,
function, and development. Japanese Dental Science Review 2016 ;52: 63-74
• CMSC covers interradicular and apical
portion regions of root.
•Thickness 400-600µm incisors, 500µm in
canines, between 300-1000µm in
premolars, 700-1500µm in molars.

57. The intrinsic fibre
predominant over
Sharpey’s fibres.
Harbours both
intrinsic and
extrinsic fibres
within calcified
matrix.
This matrix
consists of viable
cementocytes.
Increases in
thickness
throughout life.
Co-product of
fibroblasts and
cementoblasts.
Newmann, Takei, Klokkevold et al. Anatomy Of The Periodontium. In: Carranza’s Clinical
Periodontology. 11:Elsevier; 2011: 12-51

58. After the formation
of CIFC when the
periodontal ligament
becomes organized,
cementum may form
around some of the
periodontal ligament
fiber bundles.
These get
incorporated into
cementum(CIFC)
and become
partially
mineralized.
In human teeth,
incorporation of
periodontal ligament
fibers into CEFC
occurs only rarely,
essentially in the
AEFC component of
CMSC.
Newmann, Takei, Klokkevold et al. Anatomy Of The Periodontium. In: Carranza’s Clinical
Periodontology. 11:Elsevier; 2011: 12-51

59. Yamamoto T, Hasegawa T, Yamamoto T et al. Histology of human cementum: Its structure,
function, and development. Japanese Dental Science Review 2016 ;52: 63-74

60. CELLULAR INTRINSIC FIBRE CEMENTUM

61.  After atleast half the root formation, a more rapidly formed and less
mineralized cementum is deposited on the unmineralized dentin
surface near the advancing root edge.
 Doesn’t encase any Sharpey’s fibres, has organic matrix consisting of
intrinsic fibres which are synthesized by cementoblasts.
 Lacunae with cementocytes.
 Fastest growing cementum- may repair any resorptive defect in
reasonable time.
 Has no immediate role in tooth attachment Adaptive tissue
that brings and maintains tooth in proper position.
Newmann, Takei, Klokkevold et al. Anatomy Of The Periodontium. In: Carranza’s Clinical
Periodontology. 11:Elsevier; 2011: 12-51

62. INTERMEDIATE CEMENTUM
 Also known as Hyaline layer of Hopewell-Smith.
 Ill-defined zone extending from pre-CEJ to the apical third of the root.
 Appears to contain cellular remnants of HERS.
 Contains enamel like protein (amelogenin)- helps in attachment of
cementum to dentin.

63. CEMENTOENAMEL JUNCTION
 Cementoenamel junction is the anatomical boundary between enamel
on tooth crown and cementum which covers the root of the tooth-
Franchischone and Consolaro, 2008.
 It is the place where gingival fibres are attached to a tooth in a healthy
state- reference benchmark- to assess periodontal destruction-
Berendregt et al, 2009.
 Choquet, in 1899- 1st person to describe CEJ.
Roa I, Del Sol M, Cuevas J. Morphology of the cement-enamel junction (CEJ), clinical
correlations. Int. J. Morphol 2013; 31(3): 894-898

64. TYPES OF CEMENTOENAMEL JUNCTION
1.Cementum over
enamel
2.Butt joint 3.Gap junction 4.Enamel over
cementum
Roa I, Del Sol M, Cuevas J. Morphology of the cement-enamel junction (CEJ), clinical
correlations. Int. J. Morphol 2013; 31(3): 894-898

66. CLINICAL APPLICATION
In contact with the oral environment,
becomes susceptible to the
morphological changes induced by
physical agents
Esberard et al in 2007 Chemical agents such as bleaching agent
may induce detectable changes in CEJ.
Gasic et al in 2012 No changes in morphology of CEJ to
chemical agents.
Komabayashi et al in 2008 No difference between tooth surfaces,
bleaching agent will penetrate more or
less easily to the dentinal tubules and
hence affect dental pulp.
Fonseca & Fonseca in 1992 and
Satheesh et al in 2011
Type 1 & 3 are more susceptible to
caries, structural integrity causing more
adhesion of biofilms.
Roa I, Del Sol M, Cuevas J. Morphology of the cement-enamel junction (CEJ), clinical
correlations. Int. J. Morphol 2013; 31(3): 894-898

67. Palamara et al in 2006, Hur et
al in 2011
CEJ is the area where highest
number of non-carious cervical
lesions occur.
Cuniberti de Rossi & Rossi in
2009
Classes 2 & 4 are the most
susceptible to abfraction.
Roa I, Del Sol M, Cuevas J. Morphology of the cement-enamel junction (CEJ), clinical
correlations. Int. J. Morphol 2013; 31(3): 894-898

68. Continuous deposition of cementum throughout life
 At a linear rate.
 More at apical region than cervically.
 Non-functioning teeth have thicker cementum than functioning teeth.
 Increase in width of cementum by 5-10 times (Berglundh, 1991).
 There is tendency for cementum to reduce root surface concavities. Thus thicker
layers of cementum may form in root surface grooves and in the furcations of
multirooted teeth.
AGE CHANGES
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

69. RESORPTION AND REPAIR
Resorption
Pathological
Tumors
Infectious
diseases
Systemic
diseases
Nonpathological
Trauma
Mechanical
, chemical,
thermal
Over-compression
of PDL
Idiopathic
resorption
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

70. TYPES OF RESORPTION
Location
External
Internal
Degree of persistence
Transient
Progressive
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

71.  Cementum resorption is not necessarily continuous & may alternate
with periods of repair & deposition of new cementum. The newly
formed cementum is demarcated from the root by a deeply staining
irregular line, termed reversal line, which delineates the border of
previous resorption.
 Reversal lines contain a few collagen fibrils & highly accumulated
proteoglycans with mucopolysaccharides (GAGs). (Yamamoto et al,
2000).
 When the resorptive activity of the odontoclasts has ceased and the
stimulus for new odontoclasts recruitment disappears, repair occurs.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

72. REPAIR
 Morphological studies have shown that two different repair matrices
become attached to the resorbed root surface.
 Following the detachment of odontoclasts from the root surface,
cementogenic cells repopulate the Howship’s lacunae.
 Attach the initial repair matrix to a thin decalcified layer of residual
and exposed collagen fibrils.
 These cells and their respective repair tissues reveal remarkable
homologies to the initial genesis of the two major cementum varieties
(i.e., AEFC & CIFC) on growing roots.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

73.  The interdigitation of the newly formed collagen fibrils with the
residual dentinal matrix fibrils occurs before the new attachment site
becomes obscured by electron-dense material.
 Eventually, a basophilic and electron-dense reversal line forms at the
fibrillar junction.
 Subsequently deposited repair matrix usually resembles CIFC forms
on nonresorbed roots.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

74.  The strong resemblance of the initial formation of the two repair
matrices with the initiation of AEFC and CIFC on the forming root
indicates that repair cementogenesis recapitulates the events occurring
during root development,
 A notion that is in line with the views of Aukhil(1992) and MacNeil &
Somerman (1993) but in contrast with the concept hold by Pitaru et
al. (1994).
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

75. PERIODONTAL PATHOLOGY
Concrescence
 Form of fusion which occurs after root
formation.
 United by cementum
 Thought to arise as a result of traumatic injury
or crowding of teeth with resorption of
interdental bone.
 May occur before or after tooth eruption
 Diagnosed radiographically
 Extraction of one may result in the extraction
of the other.

76. CERVICAL ENAMEL PROJECTION
• Represent dipping of enamel from CEJ toward the bifurcation
• More in mandibular molars – buccal surface
• Correlated positively to localized loss of periodontal attachment
with furcation involvement

77. HYPERCEMENTOSIS
 Abnormal thickening of the cementum
 May effect all teeth of the dentition, be confined to a single tooth, or
even affect only parts of one tooth.
Cemental hypertrophy Cemental hyperplasia
If overgrowth improves functional
qualities of cementum.
if overgrowth occurs in non-
functional teeth.
Newmann, Takei, Klokkevold et al. Anatomy Of The Periodontium. In: Carranza’s Clinical
Periodontology. 11:Elsevier; 2011: 12-51

78. Types of hypercementosis :-
1. Generalized
e.g.. Paget’s disease.
2. Localized
e.g.. Low grade periapical irritation.
Newmann, Takei, Klokkevold et al. Anatomy Of The Periodontium. In: Carranza’s Clinical
Periodontology. 11:Elsevier; 2011: 12-51

79. CEMENTAL TEARS
 Detachment of a fragment of cementum from root surface, owing to
an acute injury or from intermittent episodes of sustained pressure.
 Tears have been observed within unexposed cementum as well as in
cementum exposed within the pocket.
 The cemental tears can remain partially attached or be completely
detached from the root surface.
 Caused due to excessive occlusal loading (parafunctional habits) or
due to trauma.

81. CEMENTICLES
 Cementicles are round ovoid bodies that are found on the surface of
the cementum or in the periodontal ligament.
 Cementicles may
 Lie free in the periodontal ligament adjacent to the cementum
surface - Free cementicles
 Attached to the cementum surface - Attached or sessile cementicles.
 Or incorporated into the cementum layer - Embedded cementicles.

82. They may develop from:-
 Calcified epithelial Cell Rest of Malassez.
 Small spicules of cementum or alveolar bone that are traumatically
placed in PDL.
 Calcified Sharpey’s fibers.
 Calcified thrombosed vessel in PDL.

83. DISEASES
 Neoplasms of cementum :-
-Benign cementoblastoma
-Periapical cemental dysplasia
-Gigantiform cementum
-Focal cementoosseous dysplasia
-Florid Cementoosseous Dysplasia

84. CONCLUSION
The periodontal
tissues form a
functional unit
designed to
maintain tooth
support and
protection.
In particular,
cementum, by
virtue of its
structural and
dynamic
qualities,
provides tooth
attachment and
maintainence of
occlusal
relationship.
The dynamic
features of
cementum are
particularly
highlighted by
its repair
potential.
Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue covering of the root.
Periodontol 2000, 1997; 13: 41-75

85. REFERENCE
 Bosshardt DD, Selvig KA. Dental cementum: The dynamic tissue
covering of the root. Periodontol 2000, 1997; 13: 41-75
 Gonçalves PF, Sallum EA, Sallum AW et al. Dental cementum
reviewed: Development, structure, composition, regeneration and
potential functions. Braz J Oral Sci. January/March 2005 ;4: 651-
658.

86.  Yamamoto T, Hasegawa T, Yamamoto T et al. Histology of human
cementum: Its structure, function, and development. Japanese Dental
Science Review 2016 ;52: 63-74
 Berkovitz BK, Holland GR, Moxham BJ. Cementum. In: Oral
anatomy, histology and embryology. 4. Mosby; 2009. 168-179
 Roa I, Del Sol M, Cuevas J. Morphology of the cement-enamel
junction (CEJ), clinical correlations. Int. J. Morphol 2013; 31(3): 894-
898.

87.  Tencate R. Periodontium. In : Textbook of Oral Histology. 8.
Elsevier; 2015: 205-232.
 Newmann, Takei, Klokkevold et al. Anatomy Of The Periodontium.
In: Carranza’s Clinical Periodontology. 11:Elsevier; 2011: 12-51