Anatomy of the PeriodontiumAnatomy of the Periodontium

PeriodontiumPeriodontium

The tissues that surround and The tissues that surround and support the teeth are known as support the teeth are known as the periodontium.the periodontium. It includes:It includes:

1. Gingiva1. Gingiva2. Periodontal ligament2. Periodontal ligament3. Alveolar bone3. Alveolar bone4. Cementum4. Cementum

Periodontium: peri = around . Periodontium: peri = around . odontous = toothodontous = toothPeriodontics: the art and science Periodontics: the art and science of studying the periodontium.of studying the periodontium.Periodontist: specialist in Periodontist: specialist in periodonticsperiodontics

1) Gingiva1) Gingiva

Gingiva:Gingiva:

The fibrous investing tissue The fibrous investing tissue covered by covered by keratinized epithelium. The keratinized epithelium. The gingiva is one of gingiva is one of the soft tissues that line the soft tissues that line the oral cavity.the oral cavity.

All the soft tissue in the mouth are All the soft tissue in the mouth are Known as the Known as the

the oral mucosa, it is the oral mucosa, it is

divided into three different types:divided into three different types:

Types of gingiva:Types of gingiva:

1.1. Marginal gingiva (free or Marginal gingiva (free or unattached)unattached)

2.2. Attached gingiva (firmly Attached gingiva (firmly attached to underlying attached to underlying tooth and bone)tooth and bone)

3.3. Inter-dental Inter-dental gingiva( located between gingiva( located between adjacent teeth.adjacent teeth.

4.4. Gingival sulcusGingival sulcus

Clinical featuresClinical features

Microscopic featuresMicroscopic features

ClinicalClinical

• 1)Mucogingival junction.1)Mucogingival junction.

• 2)2)Interdental gingiva.Interdental gingiva.

• 3)Free gingival groove3)Free gingival groove

• 4)4)Attached gingivaAttached gingiva..

• 5)Alveolar mucosa5)Alveolar mucosa

• 6) 6) Marginal gingiva.Marginal gingiva.

• 1:Enamel.1:Enamel.

• 2:gingival margin.2:gingival margin.

• 3:gingival sulcus.3:gingival sulcus.

• 4:free gingival groove.4:free gingival groove.

• 5:lveolar bone.5:lveolar bone.

• 6:CEJ6:CEJ

• 7Cementum7Cementum

• 8:PDL8:PDL

• Between 2 and 4 is free gingivaBetween 2 and 4 is free gingiva

Gingival sulcus:Gingival sulcus:

* * It is a shallow It is a shallow fissure between fissure between marginal gingival and the marginal gingival and the enamel or cementum.enamel or cementum.

* * Clinical normal Clinical normal gingival gingival sulcus depth = sulcus depth = 2-3 mm measured with 2-3 mm measured with periodontal periodontal probe.probe.

Interdental gingiva:Interdental gingiva:

• Its that part of the gingiva that occupy Its that part of the gingiva that occupy the inter-proximal space, created by adjacent the inter-proximal space, created by adjacent teeth in contact. Therefore, shape determined teeth in contact. Therefore, shape determined by contact relationship with teeth, and width of by contact relationship with teeth, and width of proximal surfaces.proximal surfaces.

• If the contours are flat, interproximal If the contours are flat, interproximal contacts, the gingiva will be narrow and contacts, the gingiva will be narrow and short. short. If the proximal contours are more If the proximal contours are more convex with convex with a small coronally positioned a small coronally positioned contact area, the contact area, the interdental gingiva will be interdental gingiva will be broad and high.broad and high.

The interdental gingiva can be The interdental gingiva can be pyramidal and have col shape.pyramidal and have col shape.

Buccolingual dimension the Buccolingual dimension the inter-dental gingival terminates inter-dental gingival terminates coronally with separate buccal coronally with separate buccal and lingual peaks of tissue as the and lingual peaks of tissue as the gingival col.gingival col.

Gingival Groove (4):Gingival Groove (4):

It is a shallow, v-shaped or It is a shallow, v-shaped or indentation that is closely indentation that is closely associated with apical extent of associated with apical extent of free gingiva.free gingiva.

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

Microscopic (Histological) Microscopic (Histological) FeaturesFeatures

• The gingiva consist of central core of The gingiva consist of central core of connective tissue covered by connective tissue covered by stratified squamous epithelium.stratified squamous epithelium.

Gingival Epithelium:Gingival Epithelium:

1) Oral (outer) 1) Oral (outer) Epithelium.Epithelium. 2) 2) Sulcular EpitheliumSulcular Epithelium

3) Junctional 3) Junctional EpitheliumEpithelium

Oral Epithelium:Oral Epithelium:

• Keratinized or parakeratinized consist ofKeratinized or parakeratinized consist of four layers:four layers:• 1) Stratum basale,Basal cell layer (The 1) Stratum basale,Basal cell layer (The

deepest cells)deepest cells)• 2) Spinosum cell layer2) Spinosum cell layer• 3) Stratum granulosum cell layer 3) Stratum granulosum cell layer • 4) Stratum corneum(Keratinized, para, or 4) Stratum corneum(Keratinized, para, or

nonkeratinized) cell layernonkeratinized) cell layer

Layers of Squamous Layers of Squamous epitheliumepithelium

Sulcular Epithelium:Sulcular Epithelium:

It lines the gingival sulcus It lines the gingival sulcus facing facing the tooth similar to oral the tooth similar to oral epithelium epithelium except the 2except the 2ndnd layer (it layer (it lacks granular cell layer)lacks granular cell layer)

It acts as semipermeable membrane It acts as semipermeable membrane from the bacteria and tissue fluid from the bacteria and tissue fluid from the gingiva seeps into the from the gingiva seeps into the sulcus.sulcus.

Junctional Epithelium:Junctional Epithelium:

Forms the core of epithelium. It Forms the core of epithelium. It is thickest in coronal part. Is single or is thickest in coronal part. Is single or multiple layer of non-keratinized cells multiple layer of non-keratinized cells adhering to tooth surface and face the adhering to tooth surface and face the gingiva by means of basal lamina.gingiva by means of basal lamina.

• Basal Lamina consist of:Basal Lamina consist of:Lamina lucidaLamina lucida

Lamina densalLamina densal

Details of the sulcular junctional epithelium areasDetails of the sulcular junctional epithelium areas

Connective Tissue:Connective Tissue:

Is known as the lamina propria. Is known as the lamina propria. Divided into two layers: (1) the Divided into two layers: (1) the papillary layer adjacent to papillary layer adjacent to epithelium, (2) reticular layer, epithelium, (2) reticular layer, contiguous with the periosteum.contiguous with the periosteum.– Lamina propria consist of:Lamina propria consist of:

• Collagen fibersCollagen fibers

• Intercellular ground substanceIntercellular ground substance

• CellsCells

• Blood vesselsBlood vessels

• NervesNerves

Gingival collagen fiber. Gingival collagen fiber.

• 1.circular fibers1.circular fibers

• 2.dentogingival 2.dentogingival fibers.fibers.

• 3.alveologingival 3.alveologingival fibers.fibers.

• 4.periostogingival 4.periostogingival fibers.fibers.

Histological charecterstics of the Histological charecterstics of the gingiva(Faciolingual section of the periodontium)gingiva(Faciolingual section of the periodontium)

The collagen fibers help to hold the The collagen fibers help to hold the marginal gingiva tightly against the tooth and marginal gingiva tightly against the tooth and provide a firm junction of the attached provide a firm junction of the attached gingiva to the underlying tooth root and gingiva to the underlying tooth root and alveolar bone. alveolar bone.

The fibers are grouped:The fibers are grouped:

1. Gingivodental1. Gingivodental2. Circular 2. Circular 3. Transeptal3. Transeptal4. Alveolo gingival4. Alveolo gingival5. Inter-radicular fibers5. Inter-radicular fibers6. Intra-papillary fibers6. Intra-papillary fibers

The most prominent cells found The most prominent cells found in the gingival connective tissue:in the gingival connective tissue:

1. Plasma cells1. Plasma cells

2. Fibroblasts2. Fibroblasts

3. Mast cells3. Mast cells

4. Lymphocytes4. Lymphocytes

Vascular Supply:Vascular Supply:

It’s derived from the branches of It’s derived from the branches of the superior and inferior alveolar the superior and inferior alveolar arteries:arteries:

1. Greater palatine artery1. Greater palatine artery

2. Buccal artery2. Buccal artery

3. Sublingual artery3. Sublingual artery

4. Mental artery4. Mental artery

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

Gingival Fluid:Gingival Fluid:

The gingival (crevicular) fluid is The gingival (crevicular) fluid is continually secreted from the continually secreted from the gingival connective tissues into the gingival connective tissues into the sulcus through the sulcular epithelial sulcus through the sulcular epithelial wall.wall.

This fluid helps to mechanically This fluid helps to mechanically clean the sulcus and in addition, clean the sulcus and in addition, possess anti-microbial properties and possess anti-microbial properties and antibodies that enhance the antibodies that enhance the resistance of the gingiva to gingivitis.resistance of the gingiva to gingivitis.

Clincal RelationshipClincal Relationship

Clinical Descriptive Clinical Descriptive CriteriaCriteria

Gingival color:Gingival color:

Its pink depends on:Its pink depends on:

- - amount of melaninamount of melanin

- thickness of - thickness of epitheliumepithelium

- degree of - degree of keratinizationkeratinization

- vascularity- vascularity

Gingival contour:Gingival contour:

The inter-dental gingiva is The inter-dental gingiva is generally generally pointed. However, the pointed. However, the contours of the contours of the gingiva vary gingiva vary depending upon the shape of depending upon the shape of the the teeth, the buccolingual position of teeth, the buccolingual position of the the teeth in the arch, and the size teeth in the arch, and the size of the inter-of the inter- proximal embrasure proximal embrasure space.space.

Gingival Consistency:Gingival Consistency:

Usually resilient and firm Usually resilient and firm because of the because of the dense dense collagenous nature of the gingival collagenous nature of the gingival connective tissue.connective tissue.

Gingival Surface Texture:Gingival Surface Texture:

Being stippled like an orange Being stippled like an orange peel or peel or smooth and shiny. Degree smooth and shiny. Degree of stippling of stippling varies considerably varies considerably among patients and in among patients and in different different parts of the same mouth.parts of the same mouth.

Nerve Supply:Nerve Supply:

Derived from maxillary and Derived from maxillary and mandibular mandibular branches of the branches of the trigeminal nerve.trigeminal nerve.

Periodontal LigamentPeriodontal Ligament

Periodontal ligamentPeriodontal ligament

• Connective tissue around and attach Connective tissue around and attach teeth to the alveolar bone.teeth to the alveolar bone.

• Consist of bundles of fibers, Consist of bundles of fibers, according to their directions:according to their directions:

1)Alveolar crest group1)Alveolar crest group2)Horizontal group2)Horizontal group3)Oblique group.3)Oblique group.4)Apical fibers.4)Apical fibers.

• The ends of the princible fibers are The ends of the princible fibers are embeded in cementum on the tooth embeded in cementum on the tooth side and in the alveolar bone proper side and in the alveolar bone proper on the opposite side. The embeded on the opposite side. The embeded portions of the princible fibers are portions of the princible fibers are the Sharpey’s fibersthe Sharpey’s fibers

FunctionsFunctions

• Physical (mechanical)Physical (mechanical)

• FormativeFormative

• NutritionalNutritional

• SensorySensory

The physical functions of pdlThe physical functions of pdl

• Transmission of occlusal forces to the Transmission of occlusal forces to the bone.bone.

• Attachment of the teeth to the bone.Attachment of the teeth to the bone.• Maintainance of the gingival tissues in Maintainance of the gingival tissues in

their relationship to the teeth.their relationship to the teeth.• Resistence to the impact of occlusal Resistence to the impact of occlusal

forces(shock obsorption).forces(shock obsorption).• Provision of a soft tissue casing(to protect Provision of a soft tissue casing(to protect

vessels and nerves from injury by vessels and nerves from injury by mechanical forces).mechanical forces).

Any question?Any question?

CementumCementum

Cementum:Cementum:

Calcified tissue covers the root Calcified tissue covers the root of the teeth of the teeth and provide and provide attachment to the periodontal attachment to the periodontal ligament.ligament.

Consist of collagen fibers in a Consist of collagen fibers in a ground ground substance consist of 45-substance consist of 45-50% inorganic 50% inorganic materials. 50-55% materials. 50-55% organic materialsorganic materials

Width vary from 60-68 microns in Width vary from 60-68 microns in coronal coronal third 150-200 microns in apical third 150-200 microns in apical third.third.

Width increase with age. 95 Width increase with age. 95 microns at age microns at age 20. 215 microns at 20. 215 microns at age 60age 60

Two types of cementum a cellular Two types of cementum a cellular (coronal (coronal portion of the root) Cellular portion of the root) Cellular apical portion apical portion of root and in furcation of root and in furcation areas of multi-rooted areas of multi-rooted teeth.teeth.

Cemento Enamel JunctionCemento Enamel Junction::

The area where cementum and The area where cementum and enamel meet (cervical area).enamel meet (cervical area).

Three different relationship:Three different relationship:

60-50% 60-50% cementum overlaps cementum overlaps enamelenamel

30%30% edge to edge edge to edge5%-10%5%-10% cementum fail to meet cementum fail to meet enamel resulting in exposed enamel resulting in exposed dentine dentine

• 11:dentine.2:acellular :dentine.2:acellular cementum.3:pdl with cementum.3:pdl with fibroblast.4:cementoblastfibroblast.4:cementoblast

• Cellular cementum. Cellular cementum. Cementocytes within the Cementocytes within the lacuna of cementumlacuna of cementum