Periodontics

1. Dr.R.Dhivya.,MDS

2. INTRODUCTION
DEFINITION
CONNECTIVE TISSUE OF PERIODONTIUM
 Gingiva
 Periodontal ligament
 Cementum
 Alveolar bone
CONCLUSION
REFERENCES
In Health and Disease

3.  Most widespread and abundant type of tissue in the human body.
 Major constituent is extracellular matrix, composed of fibres, ground substance & tissue fluid.
 Structurally, connective tissue can be divided into 3 classes: cells, fibres & ground substance.
 Forms a vast and continuous compartment throughout the body and has the widest variety of
functions.

4.  A tissue of mesodermal origin that consists of various cells (as fibroblasts and
macrophages) and interlacing protein fibers (as of collagen) embedded in a chiefly
carbohydrate ground substance, that supports, ensheathes, and binds together other tissues,
and that includes loose and dense forms (as adipose tissue, tendons, ligaments and
aponeuroses) and specialized forms (as cartilage and bone).
Merriam-Webster's Learner's Dictionary
.

5. The Peridontium is defined as those tissues
supporting and investing the tooth that consists of
 Cementum
 Periodontal ligament
 Bone lining the alveolus
 Part of the gingiva facing the tooth

6. GINGIVAL CONNECTIVE TISSUE- LAMINA PROPRIA
It consists of 2 layers :
1.Papillary layer
2.Reticular layer

7. Extra cellular compartment
 Fibers -60%
 Ground substance -35%
Cellular compartment -5%
 Fibroblasts -65%
 Mast cells
 Macrophages
 Inflammatory cells
Gargiulo” et al. (1961) determined that the average mean measurements for –
 Sulcus depth 0.69 mm;
 The epithelial attachment, 0.97 mm
 Connective tissue attachment 1.07 mm.

8.  Fibroblasts are of mesenchymal origin and play a major role in the
development, maintenance and repair of gingival connective
tissues.
 As with connective tissue elsewhere in the body, fibroblasts
synthesize collagen and elastic fibers, as well as the glycoproteins
and glycosaminoglycans of the amorphous intercellular substance.

9.  Numerous and are responsible for the production of
certain component of matrix
 Produce vasoactive substances which can affect the
function of the microvascular system and control the
flow of blood through the tissue
 In human periodontal disease there is an increase in
the number of mast cells that may be participating
either in the destructive events or in the defense
mechanism of periodontal disease via secretion of
cytokines.

10.  Are present in the gingival connective tissue as
components of the mononuclear phagocyte system
(reticuloendothelial system)
Two main groups designated :
 M1 "killer" macrophages
 M2 "repair" macrophages
These histiocytes have two distinct functions:
 Phagocytosis
 Antigen presentation.

11.  Neutrophils can be seen in relatively high numbers in
both the gingival connective tissue and the sulcus
 Small foci of plasma cells and lymphocytes are found
in the connective tissue near the base of the sulcus
 These inflammatory cells usually are present in small
amounts in clinically normal gingiva.

12.  Fills the space between fibers and cells
 Has high content of water
 Produced by fibroblasts some components by mast cells and others derived from blood
 Main constituents are
PROTEOGLYCANS
GLYCOPROTEINS

13. Glycosaminoglycans :
Apart from hyaluronan, all glycosaminoglycans are sulfated to varying degrees.
 Chondroitin sulfate
 Dermatin sulphate
 Heparin and Heparin Sulphate
 Keratin Sulphate
 Hyaluronan
Oligosaccharides

14. MATRIX ORGANIZERS AND SPACE FILLERS :
Aggrecan
Versican Large extracellular proteoglycans
Perlecan
Leucine rich interstitial proteoglycans Small extracellular proteoglycans
Centoglycans
CELL SURFACE PROTEOGLYCANS
Glypicans Syndecans – 1,2,3,4
Thrombomodulin CD 44
Betaglycans
PROTEOGLYCANS OF HEMATOPOIETIC CELLS
Serglycin

15.  Regulate diffusion and fluid flow through the matrix
 Determinants for the fluid content of the tissue
 Maintenance of the osmotic pressure
 They exert resistance towards deformation, thereby serving as regulators of the consistency of the
connective tissue
The important proteoglycans that are present in gingival connective tissue matrix are
 Chondroitin sulfate
 Hyaluronic acid

16.  Any of a class of proteins which have carbohydrate groups attached to the polypeptide
chain.
 Glycoproteins provide many functions : they give structural support to cells, help to
form connective tissues.
 The important glycoproteins that are present in gingival connective tissue matrix are
Elastin
Fibronectin
Laminin

17. The fibers of connective tissue can be divided into-
Collagen
The collagen fibers predominate in the gingival connective tissue and constitute the most
essential components of the periodontium
Reticular
Present in epithelium connective tissue interface and endothelium connective tissue interface
Elastic
 Present in association with the blood vessels
 Are absent in the gingiva coronal to the mucogingival junction
Oxytalan
Elaunin

18.  The firmness is achieved by the gingival tissues that are composed of type I collagen
 Type III collagen is known as fetal collagen and is important in the early phases of wound
healing and remains unmineralized.
 Collagen type VI is distributed with the elastin fibers along the blood vessels which imparts
rigidity needed to maintain the elastic blood vessel wall from undergoing permanent
deformation.
 The other collagen types associated with ECM are type II, V, X, XVIII which are dispersed
along with type I collagen.
 The anchoring fibrils consisting of type VII collagen helps to reinforce epithelial attachment
to the underlying tissue.

19.  Densely packed collagen bundles that are
anchored into the acellular extrinsic fiber
cementum just below the terminal point of
the junctional epithelium form the
connective tissue attachment.
 The stability of this attachment is a key
factor in limiting the migration of
junctional epithelium. “Cho MI ,Garant
“PR 2000

20. The connective tissue of the marginal gingiva is densely
collagenous, containing a prominent system of collagen fiber
bundles
Classified into 3 groups :
Gingivodental
Circular
Transseptal
Page et al – 2 Groups
Semicircular
Transgingival

21. Periodontal ligament: The connective tissue that
surrounds and attaches roots of teeth to the alveolar
bone. (GTP 2001)
Cellular
element
Extra
cellular
substance
Fibers
Ground
substance

22. • Synthetic cells
• Resorptive cells
• Progenitor cells
• Cells rests of Malassez
• Defense cells
CELLS
• Fibers
• Ground substances
EXTRACELLULAR
SUBSTANCES

23. 1. Synthetic cells.
Fibroblasts
Osteoblasts
cementoblasts
2. Resorptive cells
Osteoclasts
cementoclasts
3. Progenitor cells
4. Epithelial rests of Malassez
5. Defense cells
Neutrophils
Lymphocytes
Mast cells
Macrophages
Eosinophils

24.  Periodontal ligament fibroblasts are large cells with an
extensive cytoplasm
 The remodeling of collagen in the ligament is not
confined to any intermediate zone, but occurs across
the entire width of the ligament.
 Because of exceptionally high rate of turnover of
collagen in the ligament, any interference in the
fibroblast function by disease rapidly produces a loss
of the tooth’s supporting tissue.

25. Functions
 Maintain the integrity of the lacunae and canaliculi.
 Open the channels for diffusion of nutrition through the
bone.
 Play a role in removal or deposition of matrix and of
calcium when required.
 Osteoblasts first migrate away from the bone surface into
the body of periodontal ligament before eventually taking
up their functional position.
 Osteoblasts form a cell layer over forming bone surface
and act as barrier that control ion flux into out bone.

26.  These are the cells responsible for secreting the organic matrix (mainly collagen) of cementum.
 As distinct layer of cells on the root surface, similar to osteoblastic layer but not regular in arrangement.

27.  At such locations the cells occupy pits called Resorption
bays or lacunae of howship.
 Osteoclasts are formed by fusion of mononuclear cells
arising from bone marrow.
 They do not cover the whole of resorbing surface at any
one time, rather they service a much larger area by
demonstrating considerable motility.

28.  These cells only occur in certain pathologic conditions, during
resorption of deciduous teeth and when regressive forces are
applied on a tooth such as orthodontic therapy.
 These Cementoclasts resembles Osteoclasts and are located in
depressions in cementum resembling Howship’s lacuna.
 These cells not only resorb cementum, they can destroy dentin
and enamel as well thus they are also called Odontoclasts.

29.  If they were not present there would be no cells available
to replace differentiated cells lying at the end of their life
span or as a result of trauma.
 These are undifferentiated mesenchymal cells.
 These cell populations within the ligament appear to be in
highest concentrations in locations adjacent to blood vessel
and exhibit some of the classical cytological features .

30.  At the time of cementum formation the continuous layer of
epithelium that covers the surface of newly formed dentin breaks
into lacelike stands .
 The epithelial rests persist as a network stands islands or tubelike
structures near and parallel to the surface of the root .
 Their function is not clear but they could be involved in
periodontal repair and generation .
 These cells rests can be distinguished from fibroblasts in pdl by the
close packing of their cuboidal cells and their nucleus stains more
deeply .

31. These cells may undergo calcification to become
CEMENTICLES
Loe and waerhaug (1960)
After reimplantation studies observed that
 Ankylosis and subsequent root resorption never
occurred when a periodontal ligament that
contained epithelial cell rest was retained.
 These authors suggest that epithelial cell rest
may be the factor in limiting the resorption and
play a role in maintenance of periodontal space.

32.  Neutrophils are the most abundant (40% to 75%) type of white blood
cells in mammals and form an essential part of the innate immune
system.
 Neutrophils are a type of phagocyte.
 Neutrophils are recruited at the site of injury within minutes
following trauma, and are the hallmark of acute inflammation.

33.  A lymphocyte is subtypes of white blood cell in
a human’s immune system.
 These are agranulocytes.
 The three major types of lymphocyte are T cells, B
cells and natural killer (NK) cells.
 Lymphocytes can be identified by their large nucleus.

34.  Found in the ligament and are predominantly
located adjacent to blood vessels.
 Are capable of phagocytosis.
 Derived from blood monocytes.
 It has a nucleus, horseshoe or kidney shaped with
peripheral chromatin.
.

35.  These are relatively small round or oval cell having a
diameter of about 12 to 15 um .
 These cells are characterized by numerous
cytoplasmic granules called Histamine.
 Mast cells histamine plays a role in the inflammatory
reaction and have been shown to degranulate in
response to antigen – antibody reaction on their
surface .

36.  Occasionally seen in the periodontal ligament.
 These are granulocytes.
 They possess granules that consist of one or more crystalloid
structures.
 The cells are capable of phagocytosis.
 Increases in case of parasitic infections.

37. Extracellular Substance
Fibers
collagen elastic reticular
Ground
Substances

38. The main types of collagen in the pdl are
 TYPE I and TYPE III.
 Type I is uniformly distributed in the ligament.
 Type IV and VII are associated with epithelial cell rests and
blood vessels.
 A collagen subtype collagen XII which is a unique feature of
periodontal ligament as it does not normally present in other soft
tissues.

39.  Collagen XII is thought to be involved in three
dimensional architecture of periodontal ligament fibers
 Type XIII collagen is believed to occur within the pdl
only when ligament is fully functional .
 Type XVIII collagen, which is a component of
hemidesmosomes is also present in periodontal ligament
along with the desmosomal complex of proteins.

40.  There are three types of elastic fibers which are
histochemically and ultrastructurally different.
 Mature Elastic fibers , Eulanin fibers and the Oxytalan
fibers .
 Eulanin fibers and Oxytalan fibers have been described as
immature elastic fibers.
 Mature elastic fibers consist of microfibrillar component
surrounding an amorphous core of elastin protein .

41.  These are immature collagen fibers with
argyrophilic staining properties and are related to
basement membrane of blood vessels and
epithelial cells which lie within the periodontal
ligament.

42. The collagen is gathered to form bundles approximately 5 um
in diameter. These bundles are termed as PRINCIPAL FIBERS.
Within each collagen bundle , subunits are present called
collagen fibrils.
 Transseptal group
 Alveolar crest group
 Horizontal group
 Oblique group
 Apical group
 Interadicular group

43.  The collagen bundles of the periodontal ligament are
embedded into cementum and alveolar bone – similar to
that of tendon inserting into bone. These fibers are called
as Sharpey’s fibers.
 Some sharpey’s fibers are completely calcified but most
contain an uncalcified central core within a calcified
outer layer.

44. Glycosaminoglycans
 Hyaluronic acid
 Chondroitin sulfide
 Dermatan sulfate
Proteoglycans
 Versican
 Decorin
 Fibromodulin and lumican
 Periostin
Glycoproteins
 Fibronectin and laminin;
 Nidogen
 Vitronectin
 Tenascin
 Thrombospondin

45. Calcified, Avascular mesenchymal tissue that
forms the outer covering of the anatomic root.
Carranza 11th edition
CLASSIFICATION
 ACELLULAR CEMENTUM
 CELLULAR CEMENTUM

46. SHROEDER & PAGE CLASSIFICATION -1986
 1.Acellular Afibrillar Cementum (AAC)
 2.Acellular Exrinsic Fiber Cementum (AEFC)
 3.Cellular Intrinsic Fiber Cementum (CIFC)
 4.Cellular Mixed Stratified Cementum (CMSC)
 5.Intermediate Cementum

47. Chemical Composition
45-50 % Inorganic
substances
50-55% Organic
substances
consists of calcium
phosphate in the form of
hydroxy-apatite crystals
collagen fibers
embedded in a
ground substance .
Protein
Polysaccharides

48. Three types of cells are functionally concerned with cementum :
 BONE FORMING CELLS
Cementoblasts
Cementocytes
 BONE RESORPING CELLS
Cementoclast

49.  Arise from the undifferentiated mesenchymal cells
 Synthesise collagen and protein polysaccharides-
organic matrix of cementum.
 Mitochondrea, golgi, RER
 Inner cells of dental follicle: CIFC
 HERS- AEFC

50.  These locate in spaces termed lacunae & have numerous
cytoplasmic processes coursing in canaliculi, that are
preferentially directed towards the periodontal ligament.
 This is how cementocytes derive their nutrition from
periodontal ligament & contribute to the vitality of this
mineralized tissue.
 While adjacent canaliculi of neighboring cells
communicate frequently, the processes remain
independent.
 Thus, the metabolites progress mostly by diffusion through
the canaliculi of cellular cementum.

51.  They are multinucleated giant cells, which are indistinguishable from osteoclasts.
 Responsible for root resorption that leads to primary teeth exfoliation & also in the permanent
dentition in mesial surfaces in compliance with mesial migration & may occur due to occlusal
trauma & orthodontic therapy.

52.  The organic matrix of cementum is composed primarily of collagen.
 Predominantly type I and type III (Birkedal and Hansen et al 1977)
 Type I collagen plays structural as well as morphogenic role and provides scaffolding for
mineral crystals
 It is the major component accounting for 90% of organic components in cellular cementum.

53.  The type III collagen, which coats type I collagen fibrils, accounts for only 5%. (Rao et al 1979,
Wang et al 1980)
 It is a less cross-linked collagen found in high concentrations during development, repair and
regeneration of mineralized tissues

54.  Type XII collagen- A fibril associated collagen with interrupted triple helices that binds to type
1 collagen and also to non collagenous proteins
 Trace amounts of Type XIV are also found in extracts of mature cementum, however these may
be contaminants from periodontal ligament.
 Based on immunostaining, the cementum does not appear to have either Type V or Type VI
collagen (Becker and Romanos et al 1991)

55.  Bone sialoprotein
 osteopontin
 Fibronectin
 Tenascin
 Osteonectin - SPARC(Specific Protein Acidic Rich in Cysteine)
Proteoglycan
 Versican,
 decorin,
 biglycan,
 syndecan

56.  Alveolar bone is defined as the parts of maxilla and mandible that form and support the socket of
teeth.
 Together with the root cementum and periodontal ligament, the alveolar bone constitutes the
attachment apparatus of the teeth

57. Alveolarbone
Acellular
component
Cellular
component

58.  Derived from multipotent UNDIFFERENTIATED
mesenchymal cells or alternatively from perivascular
cells (PERICYTES).
 Secretes both “collagenous (type 1 collagen) and non
collagenous” bone matrix – OSTEOID .
 Osteoblasts exhibit high level of alkaline phosphatase
on their outer plasma membrane - believed to
contribute - initiation of bone mineralization

59.  Most abundant bone cells .
 Communicate with each other and with other cells on
surface of the bone via dendritic process encapsulated
in canaliculi
 Play role in calcium homeostasis
 Exchange of metabolic and biochemical messages
occurs between blood stream and canaliculi

60.  Generally occur in clusters.
 They have prominent mitochondria, lysozomes,
vacuoles and few endoplasmic reticulum.
 Activity is controlled by PTH
 They are found against the bone surface, occupying
shallow depressions called Howship’s lacunae surfaces
or in deep resorption cavities called cutting cones.

61.  Similar to osteocytes – i.e., osteoblasts that do not get embedded
 in newly formed bone ,gets adhered to the outer surface of the bone
 …..when bone formation halts.

62. Bone
33% organic
28% collagen
5% non
collagenous
proteins
67% inorganic Hydroxyapatite

63.  Type I collagen makes up about 90% of the
organic matrix.
 Type I collagen forms fiber bundles that
provide basic structural integrity to bone.
 In addition to this type V, III & XII are also
present. Type III collagen is present in relation
to Sharpey’s fibers.
 Type I, V & XII are produced by osteoblasts
and type III is produced by fibroblasts.
 The remaining 10% consists of non-
collagenous components
80- 90% of organic
component
TYPE
III & XII
TYPE I
TYPE
V(5%)

64.  Bone sialoprotein
 Osteonectin - SPARC(Specific Protein Acidic Rich in Cysteine)
 osteopontin
 Glycosaminoglycans
 Versican
 Decorin and biglycan
 Osteocalcin
 Bone morphogenic proteins

65. CONNECTIVE TISSUE IN DISEASE

66.  Gingivitis – perivascular extracellular matrix – collagen within foci of inflammation
is degraded.
 Cause – MMPs produced by PMNs.
 Periodontitis – MMPs by PMNs , macrophages , fibroblasts and keratinocytes.
 Foci of inflammation may ,manifest as scarring and fibrosis.

67.  In gingiva – collagen becomes more soluble.
 Type I and III are lost at the foci of inflammation.
 Collagen ratios are altered.
 Type V increased and more than type III.
 New type Type I trimer are also found in inflammed gingiva.

68.  Destruction carried out by MMPs especially from PMNs and macrophages.
 Imbalance between activated MMPs and endogenous inhibitors.- Reynolds and Meikle 1997
 Proteoglycans are affected but the damage is less than that of collagen.
 Dermatan sulfate decreases
 Chondroitin sulfate increases.

69.  Degradation of proteoglycan core proteins and hyaluronic acids are characteristic feature of
inflammed gingival connective tissues. (Bartold and page 1986)
 PDL manifests changes in distribution of glycosaminoglycans
 Major change is increase in presence of chondroitin sulphate.
 Changes to the hard tissue matrix of bone and cementum differ significantly due to their
different anatomical location.

70.  Complication of medication
 Matrix elements are lost during gingivitis but accumulated in gingival overgrowth.
 Excessive accumulation of Connective tissues - especially collagen is affected.
 Types I , III , V and VI collagens and fibronectin are present.
 Collagen type I and type III ratio are altered.
 Collagen type III is increased.

71.  In healthy – noncollagenous matrix 7 %
 In phenytoin induced overgrowth - 20 % Ballard and Butler 1974
 Higher contents of hexosamine , uronic acid , glycosaminoglycans and proteoglycans , and also
glucocorticoid receptors.
Reason for accumulation in gingival overgrowth
 Decreased levels of matrix degrading enzymes in these lesions.
 Or induction of matrix production.

72.  Age related changes
 Change occurs in collagen synthesis
 Decreased collagen sollubility
 Increased cross linking
 However collagens of gingiva and pdl – high turnover with advancing age.
 Type I and type III usually increases with age.
 Anticollagenase tissue inhibitor appears in lesion.

73. Mechanisms of periodontal tissue destruction
 Enzyme mediated damage by host cells
 Tissue degrading enzymes from bacterial cells
 Phagocytosis of matrix components
 Free radicals in tissue destruction
 Effect of Soluble mediators on connective tissue cells

74.  MMPs – degrade interstitial or basement membrane collagens - laminin , fibronectin , core
proteins of proteoglycan.
 Produced by PMNs , macrophages , fibroblasts , keratinocytes and endothelium.
 Activated by plasmin

75. Cell type MMP type Inducers
Fibroblast MMP- 1 2 3 IL-A,B;TNF-A;PDGF
Keratinocytes MMP – 1 2 9 10 LPS;TGF-A
Monocytes,Endothel
ial cells
MMP – 1 2 3 9 LPS
PMN MMP 8 9 LPS

76.  Plasminogen – plasmin.
 Activated by u – PA ( Plasma membranes ) and t – PA ( fibrin surfaces ).
 At site of inflammation plasminogen activating system is high.
 Affects matrix macromolecules other than collagen . Also affects collagen by activating MMPs.

77.  Inhibitors
 Alpha 1 proteinase inhibitor
 Alpha 2 macroglobulin
 Alpha 2 antiplasmin
 PAI 1 and PAI 2.
 PAI 2 is an important inhibitor of tissue proteolysis in periodontal tissues. (Kinnby 1994)
 In periodontitis plasmin is formed at sites of inflammation, activates the proMMPs into
proteases which are specific for elastin and collagen, also responsible for the degradation of
fibrin and extracellular matrix (ECM) Buduneli N, 2005

78.  Microbial collagenases
 Enzymes with trypsin like activities.
 Regulates MMPs by activating them or degrades the inhibitors.
 Acts as antigens – cytokine production
 Inflammed gingiva – hydrolytic enzymes beta glucuronidase , aryl sulfatase , hyaluronidase ,
chondroitinase.
 The substrate for above enzymes are hyaluronan and proteoglycan.
 Breakdown of glycosaminoglycan chains.

79.  Fibroblasts and macrophages – degradative pathway for collagen.
 Requisite – proteolytic digestion prior to cell ingestion of collagen.
 Phagosome + lysosome (cathepsin L)
 Cells defective in phagocytic process may lead to tissue overgrowth.
 Mechanism still unclear.

80.  ROS high in cells undergoing respiratory bursts.
 Consequence of electron transport chain or metabolism.
 MPO and NADPH
 Arachidonic acid metabolism
 Tissue destruction when produced in excess.

81.  Superoxide radical – direct toxic action on cells.
 Pathogenesis of inflammation induced tissue destruction.
 Hydroxyl radical – short lived , hydrogen peroxide –long lived.
 HOCL – activation of collagenases and gellatinases.
 Potential to play role in matrix destruction in inflammed periodontitis.
 Eg oxygen derived free radial may depolymerize gingival proteoglycans and hyaluron , activate
neutrophil collagenase , and thus initiate matrix degradation. (sorsa 1989)

83. THANK YOU