The document provides an overview of the normal anatomy of the periodontium. It describes the four main components - gingiva, periodontal ligament, cementum, and alveolar bone. It then discusses the histology and clinical characteristics of each component, with a focus on the gingiva. Key points include that the gingiva is made up of epithelium and connective tissue, with the epithelium consisting of sulcular, junctional, and oral epithelium. The connective tissue contains collagen fibers and cells. Clinically, healthy gingiva is pale pink, resilient, and has a stippling surface texture.

1. An Introduction to Periodontology Course&
normal anatomy of periodontium
Prepared by
Dr. Hisham Abozaid
Lecturer of oral Medicine & periodontology

2.  Normal periodontium : (Clinical and Histological Characteristics):
Gingiva, Periodontal ligament, Cementum, alveolar bone.
 Pathogenesis of periodontal disease
 Etiology of Periodontal disease: local & systemic
 Classification of Periodontal diseases
 Gingival lesions
 Periodontal lesions
 Diagnosis, Prognosis and Treatment plan
 Treatment :
 Non-surgical Periodontal Therapy
 Surgical Periodontal Therapy

3. Anatomy of the Periodontium
Clinical and Histological Characteristics

4. Objectives
 What is meant by periodontium? What are its various
components?
 Describe criteria & functions of each component of
periodontium.
The term periodontium arises from the Greek word peri
meaning around & odont meaning tooth.

5.  The various diseases of the periodontium are
collectively termed as periodontal diseases.
 Their treatment is referred to as periodontal therapy.
 The clinical science that deals with the periodontium in
health & disease is called periodontology.
 The branch of dentistry concerned with prevention &
treatment of periodontal disease is termed
periodontics .

6.  Masticatory mucosa:
firmly attached to underlying bone. gingiva
& hard palate
 Specialized mucosa:
Covers the dorsal surface of the tongue.
 Lining mucosa:
Loosely attached to underlying structures &
lines remainder of the oral cavity as Lips,
cheeks, floor of the mouth.
Oral mucosa consist of 3 zones:

7.  Periodotium defined as the “tissues investing and
supporting the teeth”.
 Composed of :
 2 hard tissues:
alveolar bone,
cementum,
 2 soft tissues:
periodontal ligament (supporting tissues)
gingiva (investing tissue).
Periodontium

8.  Normal gingiva is that part of oral mucosa, which
covers the alveolar bone & tooth root to a level just
coronal to the cementoenamel junction.
 The main function of the gingiva is to protect the
surrounding tissues from the oral environment.
Gingiva

9. The gingiva divided into three parts:
1. Marginal gingiva
(free or unattached)
2. Attached gingiva
(firmly attached to
underlying tooth & bone)
3. Interdental papillae
( located between
adjacent teeth).
Gingiva

10. Surface characteristics of the clinically-normal gingiva

11. Clinically
1)Mucogingival junction.
2)Interdental gingiva.
3)Free gingival groove
4)Attached gingiva.
5)Alveolar mucosa
6) Marginal gingiva.

12. Marginal(free) gingiva
• The most coronal portion of gingiva.
• well-adapted to tooth surface but not
attached to it.
• creates soft tissue wall of the gingival
sulcus.
• In health, knife-edged in contour &
smooth in texture.

13. Marginal(free) gingiva
• extends apically to free gingival
groove, approximately 1 mm wide.
• It may be separated from
the tooth surface with
a periodontal probe.
• The most apical point of the marginal
gingival scallop is called the gingival
zenith.

14. Attached Gingiva
• firmly bound to the underlying tooth & alveolar bone.
• stippled in texture, and firm & resilient in consistency and
covered by keratinized epith.
• Bound coronally by free gingival
groove & apically by
mucogingival junction.
• can withstand
mechanical forces
of brushing & tension
applied on mucosa.

15. Width of Attached Gingiva
• important clinical parameter.
• the distance between
mucogingival junction &
the projection on the external surface
of the bottom of the gingival sulcus.
• should not be confused with the width of the keratinized gingiva
because the latter also includes marginal gingiva
• Greatest in incisor region (3.5-4.5 in maxilla, 3.3-3.9 in
mandible). & Least in premolar area (1.9 mm in maxilla, 1.8 in
mandible).

16. Interdental gingiva (papilla)
 portion of free gingiva located in inter-proximal space created by
contact between two adjacent teeth.
 pyramidal in anterior region & tent shape in posterior region.
 The shape of interdental papilla depends on :
 the presence or absence of a contact point between the adjacent
teeth,
 the distance between the contact point
& the osseous crest
 Presence or absence of some degree of
recession.

17.  Facial & lingual papillae are connected together by a valley-like
depression called “Col” made up from non keratinized epithelium
& represents the most frequent site for initiation of disease process.

18. • If a diastema is present,
the gingiva is firmly bound
over the interdental bone
& forms a smooth,
rounded surface without
interdental papillae

19. Gingival sulcus
* a -V- shaped shallow crevice
around the tooth, bounded by the
tooth surface in one side & the
epithelial lining the marginal gingiva
on the other side.
* Clinical normal gingival sulcus
depth = 0-3 mm measured with
periodontal probe & it is important
diagnostic parameter.

20.  There is a fluid secreted from gingival C.T into the sulcus
through the thin sulcular wall termed as gingival fluid.
 Its secretion increases with tissue inflammation and during
chewing.
 contains a vast array of biochemical factors, thereby offering its
potential use as a diagnostic or prognostic biomarker of the
biologic state of the periodontium in health & disease.
Gingival (Crevicular) Fluid

21. Components of sulcular fluid
1. Cellular elements : bacteria, desquamated epithelial cells, PMNs,
lymphocytes and monocytes.
2. Electrolytes: potassium, sodium and calcium,
3. Organic compounds: as carbohydrates, proteins and
immunoglobulin (IgA, IgM), complement C3 and C4, plasma proteins,
4. Metabolic & bacterial products: lactic acid, urea, hydrogen
sulfide, endotoxinns.
5.Enzymes: alkaline phosphatase, lysozomes, proteases, lactic
dehydrogenase.

22. Functions of Gingival (Crevicular) Fluid
 Its flow washes out irritants & prevent bacterial penetration.
 Its plasma proteins improve epithelial adhesion to the teeth.
 Has antibacterial effect upon many oral microorganisms.
 Has defense mechanism by its immunoglobulin contents.
 Essential growth factor for many microorganisms.

23. The understanding of clinical features
of periodontium is enhanced by a
knowledge of histological component of
tissue.

24. Microanatomy of the gingiva
Histological Features
 The gingiva consist of central core of connective tissue
covered by stratified squamous
epithelium.
 the epith. is predominantly
cellular in nature.
 C.T is less cellular & composed
primarily of collagen fibers &
ground substance

25. Gingival Epithelium
 Functions of gingival epith.
 provide a physical barrier to infection & the
underlying gingival attachment
 play an active role in innate & acquired host
defense.
 Composed of
1)Oral (outer) Epithelium: facing oral cavity
2) Sulcular Epithelium: facing tooth surface
3) Junctional Epithelium: forms
the junction between gingiva & tooth surface

26. Cells of the gingival epithelium
􀂆Keratinocytes(keratin producer cells): 90% of gingival
epithelial cells.
􀂆Non keratinocytes :
• Melanocytes: produce melanin, which is a pigment found
in the skin, eyes, hair, and gingiva
• Langerhans cells : important role in the immune
reaction as antigen-presenting cells for lymphocytes
• Merkel cells: harbor nerve endings& identified as tactile
perceptors

27. Oral Epithelium
covers the crest, outer surfaces of marginal & attached gingivae;
consists of keratinized stratified squamous epithelium arranged in 4
layers:
 Stratum basale, Basal cell layer (The deepest): possessing ability to
undergo mitotic division.
 Stratum Spinosum , prickle cell layer: cells are polyhedral and
attached by desmosomes.
 Stratum granulosum, granular cell layer: contains keratohyaline
bodies and glycogen granules.
 Stratum corneum, Keratinized cell layer (Keratinized, para, or
nonkeratinized) : cytoplasm is filled with keratin

28. Layers of Squamous epithelium

29.  lines the gingival sulcus facing the tooth extending from
coronal limit of junctional epith. to the crest of gingival
margin.
 acts as a semipermeable membrane through which bacterial
products can passes & tissue fluid can seeps.
 It is thin non-keratinized stratified squamous
epith. without rete pegs & lacks stratum
granuolosum and corneum
Sulcular Epithelium

30. Junctional Epithelium (Epithelial attachment)
 the tissue that joins the tooth on one side and to sulcular epith. & C.T
on the other. It forms the base of the sulcus.
 consists of collar-like band of thin non-keratinized stratified squamous
epith.
 The junctional epithelium is attached to the tooth
by internal basal lamina & to gingival C.T by
external basal lamina.

31. Junctional Epithelium (Epithelial attachment)
Exhibits several unique structural & functional features that contribute to
preventing pathogenic bacteria from colonizing subgingival tooth
surface:
 firmly attached to the tooth surface, forming an epithelial barrier
against plaque bacteria.
 allows access of gingival fluid, inflammatory cells, and components of
the immunologic host defense to the gingival margin.
 junctional epithelial cells exhibit rapid turnover, which contributes to
the host-parasite equilibrium & rapid repair of damaged tissue.

32. Junctional Epithelium (Epithelial attachment)
 Attachment of the junctional epith. to the tooth is reinforced by the
gingival fibers, which brace the marginal gingiva against the tooth
surface. For this, the junctional epith. and the gingival fibers are
considered a functional unit, referred to as the dentogingival unit.
 Three zones in junctional epith. have been described, apical, coronal
and middle. Apical is for germination, middle is for adhesion and
coronal is permeable.

33. Connective Tissue(lamina propria)
Divided into two layers:
(1) superficial papillary layer between epithelial retepegs,
(2) deep reticular layer, over the periosteium of the
alveolar bone.
 Lamina propria consist of:
 mainly Collagen fibers (60%)
 Cells mainly fibroblasts(5%)
 Intercellular ground substance
 Blood vessels, lymphatic,
Nerves

34. Gingival collagen fibers
 Functions:
 brace the free gingiva firmly against the tooth
 Provide rigidity to resist the force of mastication
 unite the free marginal gingiva with the cementum of the root &
adjacent attached gingiva.
 Composed mainly of collagen type I.
 Gingival collagen fibers may be:
Primary Fibers
Secondary Fibers

35. Primary gingival fibers
 Circular fibers: surround tooth in
ring like fashion & course through C.T of
marginal & attached gingiva
 Dentogingival fibers: from
cementum in a fan-like towards the crest
& outer surface of marginal gingiva.
 Alveologingival fibers: from
periosteum of alveolar crest coronally
into lamina propria.
 Dentoperiosteal fibers: from the
cementum near CEJ & insert into
periosteum of alveolar bone
 Transseptal fibers: interproximally
from cementum of one tooth to
cementum of the neighboring tooth

36. Secondary gingival Fibers
Semicircular fibers (SCF): from mesial
surface of a tooth to distal surface of
same tooth in a half circle
Transgingival fibers (TGF): these fibers
traversing from CEJ to free gingiva of
adjacent tooth
Intergingival fibers (IGF): extend along
facial and lingual marginal gingiva from
tooth to tooth.

37. Fibroblast: They are the predominant cells, they are
functioning to
1.Synthesize and secrete collagen fibers, elastin, non-collagenous
proteins, glycoprotein
2. Renewal of collagen fibers and other constituents.
3. Regulation of gingival wound healing.
Plasma cells
Mast cells
Lymphocytes
PMNs
Cellular Elements of Gingival Connective Tissue

38. • The extracellular matrix (ground substance) fill
the space between fibers and cells, and has high
content of water.
• It is composed of proteoglycans (mainly hyaluronic
acid) and glycoproteins (mainly fibronectin).

39. Vascular Supply
It’s derived from the branches of the superior and inferior
alveolar arteries:
 Supraperiosteal vessels: along facial and lingual surface of the
alveolar bone sending branches to the sulcular epithelium and
C.T. papillae between retepegs.
 Periodontal ligament vessels: extend into gingiva and
anastomose with the capillaries in the sulcular area.
 Terminal branches of intraseptal artery: extend parallel to the
crest of the bone and anastomose with supraperiosteal and
periodontal ligament vessels.

40. Blood supply of the gingiva: (1) inferior alveolar artery, (2) dental artery, (3) intraaseptal artery,
(4) periodontal ligament vessels, (5) terminal branches of intraseptal artery, (6) supraperiosteal
vessels, (7) subepithelial plexus, and (8) dentogingival plexus.

41. The lymphatic drainage usually
follows the blood supply, the major
portion of the lymph drainage from the
gingiva going to the submandibular
lymph nodes.

42. Nerve Supply
Innervations of the gingiva is derived from maxillary and
mandibular branches of trigeminal nerve. Thus, these
innervations are derived from fibers arising from nerves in
periodontal ligament and from the labial, buccal and palatal
nerves as following:
Surface Maxillary Gingiva Mandibular Gingiva
Anterior
Teeth
Posterior
Teeth
Anterior
Teeth
Posterior
Teeth
Buccal (facial) Iinfra-orbital
nerve (Labial
branch)
Superior
Alveolar
Nerve
Mental Nerve Long Buccal
Nerve
Lingual
(palatal)
Nasopalatine
Nerve
Anterior
Palatal
Nerve
Lingual Nerve Lingual Nerve

43. Clinical Descriptive Criteria of healthy gingiva
Gingival color
 It is pale pink depends on:
- amount of melanin
- thickness of epithelium
- vascularity
- degree of keratinization
 Melanin pigmentation is prominent in black
individuals occurs as a diffuse, deep-purplish
discoloration or as irregularly shaped, brown &
light-brown patches. (racial pigmentaation)

44. Gingival contour
-Free gingiva overlaps the teeth in a collar-
like fashion, ending as knife edge and follows
scalloped outline.
-Pointed interdental papillae
-Festooned appearance

45. Gingival Consistency
Usually resilient and firm because of the
dense collagenous nature of the gingival
connective tissue.
Gingival size
absence of swelling & edema. Changes
in gingival size indicate periodontal disease.

46. Gingival Surface Texture
• Orange peel or stippling, mainly in the attached gingiva
and the center of interdental papillae.
• It results from alternate elevations and depressions
produced by papillary connective tissue between epithelial
rete pegs .

47. Shape
the interdental papillae are pyramidal in anterior teeth & tent in
posterior teeth.
Position (refers to the level at which the gingival margin is attached to
the tooth):
Clinical crown (which not covered with gingiva) is approximately 2/3
of anatomical crown (tooth portion covered by enamel).
Gingival sulcus : normal (0-3mm)
Bleeding: No bleeding on probing

48. Periodontal ligament(PDL)
 a complex vascular & highly cellular C.T that surrounds the tooth root
& connects it to the inner wall of the alveolar
bone.
 In the coronal direction, PDL is continuous
with C.T of the gingiva & communicates with
the marrow spaces of the alveolar bone.
 Average width of PDL space is about 0.25mm.
 The periodontal space is diminished around teeth
that are not in function & in unerupted teeth, but is
increased in teeth subjected to hyperfunction.

49. Periodontal ligament components
 Periodontal fibers
-the principal fibers
-Secondary fibers
 Cellular elements
 Ground substance
-Proteoglycans
-Glycoproteins

50. Periodontal fibers
The most important elements of PDL are the principal fibers, which are collagenous
(mainly type I) & arranged in bundles in six groups that develop sequentially in the
developing root & follow a wavy course.
1)Transseptal group
2)Alveolar crest group
-to retain tooth in socket
-resist lateral tooth movement
3)Horizontal group
4)Oblique group(the largest group)
resist axially directed forces
5)Apical group
prevents tooth tipping;
resists luxation
6) Interradicular group
resists luxation &
tipping & torquing.

51. Periodontal fibers
 The ends of the principal fibers are embedded in cementum on the tooth side &
in the alveolar bone proper on the opposite side. The embedded calcified
portions of the principal fibers are the Sharpey’s fibers

52. Secondary fibers of periodontal ligament
 In addition to the principal fiber groups, PDL contains other
well-formed fiber bundles, that inter-digitate at right angles or
splay around & between the regular fiber bundles.
 These fibers are associated with blood vessels & nerves of the
PDL.

53. Cellular elements of PDL
Four types of cells have been identified in PDL:
 Connective tissue cells,
 Epithelial rest cells,
 Immune system cells,
 Cells associated with neurovascular elements.

54. Cellular elements of PDL
1) Connective tissue cells
 Fibroblasts
 (65% of total cell population) the most prominent cells in PDL.
 synthesize collagen & possess the capacity to phagocytose old collagen fibers &
degrade them by enzyme hydrolysis.
 The main function of fibroblasts is the production of various types of fibers(
Collagen , Reticulin ,Oxytalan ,Elastin fibers) & in the synthesis of connective
tissue matrix.
 Other cells:
Osteoblasts & Osteoclasts,Cementoblasts & odontoclasts: seen in
the cemental & osseous surfaces of PDL.

55. Cellular elements of PDL
2) The epithelial rests of Malassez
 considered remnants of the Hertwig root sheath, which disintegrates during root
development.
 Although their functional properties are still unclear, the epithelial rests are
reported to contain keratinocyte growth factors & In addition, epithelial rests
proliferate when stimulated & they participate in the formation of periapical cysts
& lateral root cysts.
3) immune system cells: neutrophils,lymphocytes, macrophages, mast cells &
eosinophils.
4) cells associated with neurovascular elements.

56. Functions of PDL
 Physical Functions
1. Provision of a soft-tissue “casing” to protect the vessels & nerves
from injury by mechanical forces
2. Transmission of occlusal forces to the bone
3. Attachment of the teeth to the bone
4. Maintenance of the gingival tissues in their proper relationship to the
teeth
5. Resistance to the impact of occlusal forces (shock absorption)

57. Functions of PDL
 Formative& remodelling : provide cells that has the ability to form
as well as resorb all the tissues that make up the attachment apparatus.
 Sensory: PDL is supplied by nerve fibers that can transmit sensation
of touch, pressure & pain to higher centers.
 Nutritive: supplies nutrients to cementum, bone& gingiva by way of
the blood vessels.

58. PDL clinical considerations
 PDL cells are capable of remodeling the ligament & adjacent bone
when functional forces are altered or the ligament is damaged as
in Orthodontic Tooth Movement
-Depends on resorption & formation of both bone & PDL. These
activities can be stimulated by properly regulated pressure & tension.
-If the movement of tooth is within physiological limits, the
compression of PDL on pressure side results in bone resorption,
where as on the tension side, bone apposition is seen.
-Application of large forces results in necrosis of PDL & alveolar
bone.

59.  PDL plays a key role in protecting the tooth from being resorbed
by the normal remodeling process that affects the adjacent
alveolar bone.
 Accidentally exfoliated teeth can be replanted.
 PDL is unique among the periodontal tissues, in that it contains
precursor cells for the production of the entire attachment
apparatus of the tooth, i.e. cementum, PDL & bone
PDL clinical considerations

60. Cementum
 Calcified avascular tissue that forms the outer covering of the
root of the teeth & provide attachment to the periodontal
ligament.
 Consist of collagen fibers in a ground substance consist
of 45-50% inorganic materials. 50-55% organic
materials.
 Has no vascular or nerve connection.
 Characterized by continous deposition throughout life.

61. Two types of cementum
Acellular (primary) & Cellular (secondary)
 Both consist of a calcified interfibrillar matrix & collagen fibrils.

62. Functions of cementum
a. Primary function of cementum is to provide anchorage to the
tooth in its alveolus. This is achieved through the collagen fiber
bundles of PDL, whose ends are embedded in cementum.
b. Cementum also plays an important role in maintaining occlusal
relationships, whenever the incisal & occlusal surfaces are abraded
due to attrition, the tooth supra erupts in order to compensate for the
loss & deposition of new cementum occurs at the apical root area.

63. Cemento Enamel Junction
 The area where cementum and enamel meet (cervical area).
 Three different relationships
• 60-65 %  cementum
overlaps enamel
• 30% edge to edge
• 5%-10% cementum
fail to meet enamel resulting
in exposed dentin &hypersensitivity.

64. Hypercementosis or cemental hyperplasia:
 a prominent thickening of cementum, localized or generalized. Exact etiology is
unknown.
 Hypercementosis of entire dentition may be hereditary & occurs in Paget’s disease.
 does not require treatment. It could pose a problem if an affected tooth requires
extraction. In a multirooted tooth, sectioning of the tooth may be required before
extraction
Cementicles:
 are globular calcified masses adherent to or detached from the root surface.
 They may be developed from calcified epithelial rests, calcified Sharpey’s fibers, &
calcified thrombosed vessels within PDL.
Cementomas:
 They are masses of cementum, situated apical to tooth & may or may not attach to
the apex.
Development & acquired abnormalities of cementum

65.  Cementum resorption may be due to local or systemic causes:
 Local: trauma from occlusion; orthodontic movement; cysts,
tumors, replanted and transplanted teeth, teeth without functional
antagonist, periapical disease & periodontal disease.
Systemic: calcium deficiency, hypothyroidism, Paget's disease
Idiopathic
 Cementum resorption is not continous, may alternate with periods
of repair.
Cementum Resorption & Repair

66.  Fusion of the cementum & alveolar bone with
obliteration of PDL.
 occurs in teeth with resorbed cementum which may represent a
form of abnormal repair , it may develop following chronic
periapical inflammation & occlusal trauma.
 Clinically, ankylosed teeth lack the physiologic
mobility of normal teeth, which is one diagnostic sign
for ankylotic resorption.
Ankylosis

67.  Ankylosis results in the resorption of the root &
its gradual replacement by bone tissue. For this reason,
reimplanted teeth that ankylose will lose their roots
after 4 to 5 years and will be exfoliated.
 Treatment modalities range from a conservative approach, such as
restorative intervention, to surgical, such as the extraction of the
affected tooth.
Ankylosis

68. Clinical considerations
 It provides a protective function to the tooth itself, as it is less susceptible to
resorption than bone. This allows movement of the tooth through bone, as in
orthodontics, while minimizing resorptive damage to the tooth.
 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 sensitivity.
 New cementum formation is a key process during therapeutic procedures aimed
at gaining new fibers of PDL.
 Cemental deposition in apical portion of the root compensates to some degree
for the slow tooth eruption that takes place throughout life to compensate for
occlusal attrition.

69. Alveolar bone
the portion of the maxilla & mandible that forms & supports the tooth socket (alveoli).

70. Alveolar bone
􀂆Consists of
• Alveolar bone proper (inner socket wall). cribriform plate or lamina
dura (x-ray term). thin compact bone arranged in layers parallel to
the root surface & contains Sharpey’s fibers of PDL.
• Outer layer of compact bone
• Supporting alveolar bone
cancellous (trabecular) bone, contains
marrow spaces between the two
compact layers.

71. Alveolar processes are divided anatomically into various
parts
depending on relationship to teeth they surround:
1. Interproximal bone (interdental septum): between
the adjacent teeth.
2. Radicular bone: located on
facial or lingual tooth surface.
3. Interadicular bone: located
between roots.

72. Bone components
1. Extracellular matrix
• 2/3 inorganic matter mainly calcium + phosphate in the form of
hydroxyapatite crystals.
• 1/3 organic matrix mainly collagen type I.
2. Bone cells:
 Osteoblast: deposits organic matrix that will be mineralized later
& form bone.
 Osteoclast: bone resorbing cell.
 Osteocytes

73. Periosteum & Endosteum
 The tissue covering the outer surface of bone is termed as
periosteum, where as the tissue lining the internal bone cavities is
called endosteum.
 The periosteum consists of two layers,
 the inner layer: next to the bone surface, consists of bone cells
that have the potential to differentiate into osteoblasts.
 an outer layer which is more fibrous containing blood vessels
& nerves.
 The endosteum is composed of a single layer of
osteoprogenitor cells & a small amount of C.T.

74. Alveolar bone processes & cementoenamel junction
The coronal margin of the alveolar bone shows a wavy
configuration that corresponds to the course of
cementoenamel junctions & it is situated 1 to 2 mm from
these junctions.

75. • Isolated areas in which the root is denuded of bone & the root surface is covered
only by periosteum & overlying gingiva are termed fenestrations. marginal bone
is intact.
• When the denuded areas extend through the marginal bone, the defect is called
dehiscences.
Fenestrations & Dehiscences
Variations in Normal Structure of Alveolar Bone

76. • Site : Such defects occur on approximately 20% of the teeth
more often on the facial bone than on the lingual & more
common in anterior teeth than on the posterior.
• The etiologies of these defects are not clear;
• predisposing factors : root prominence, malposition, and teeth in
labial version with thin bony plates.
• Importance: Fenestration & dehiscence are important, because
they may complicate the outcome of periodontal surgery.
Fenestrations & Dehiscences

77. Clinical Considerations
 Bone although one of the hardest tissue of human body, is
biologically a highly plastic tissue. Bone is resorbed on the side of
pressure & apposed on the side of tension.
 The most frequent & harmful change in alveolar process is that
which is associated with periodontal disease. The bone
resorption caused by this is usually symmetrical, occurs in episodic
manner, & is both of the horizontal and vertical type. Once lost, this
bone is very difficult to regenerate. Regeneration of just a few
millimeters of bone is the greatest challenge to the periodontists
across the world.

78. Defense mechanisms of the gingiva
1.The intact status of epithelium coverage.
2. Gingival crevicular fluid (GCF).
3. The saliva.
4. Initial stage of inflammatory response.

79. Gingival Epithelium
Gingiva has an intact surface, constitutes a continuous lining
of stratified squamous epithelium. Its main function is to
protect the deep structures & allowing selective interchanges
with the oral environment.

80. Gingival crevicular fluid
 contains a vast array of biochemical factors, offering potential use
as a diagnostic or prognostic biomarkers of the biologic state of the
periodontium in health and disease.
 In the healthy sulcus, the amount of gingival fluid is very small,
while during inflammation, the gingival fluid flow increases & its
composition start to resemble that of an inflammatory exudate.
 It seeps from the gingival C.T through the thin sulcular epitehlium
into the gingival sulcus.

81. The Saliva

82. Thank you