Dentistry: The Normal Periodontium and Gingiva

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Questions and Answers

What is the function of the marginal gingiva?

To produce saliva

To cover the alveolar processes of the jaws

To form the soft tissue wall of the gingival sulcus (correct)

To support the teeth

What is the gingival sulcus?

A shallow crevice or space around the tooth neck (correct)

A deep crevice or space around the tooth pulp

A deep crevice or space around the tooth crown

A shallow crevice or space around the tooth root

What is the width of the marginal gingiva?

About 10 mm

About 0.5 mm

About 1 mm (correct)

About 5 mm

What is the attached gingiva?

A firm, resilient part of the gingiva Signup and view all the answers

What determines the shape of the interdental gingiva?

Both of the above Signup and view all the answers

What is the histological composition of the gingiva?

Stratified Squamous Epithelium (SSE) and connective tissue Signup and view all the answers

What is the normal depth of the gingival sulcus?

2-3 mm Signup and view all the answers

What happens to the width of the attached gingiva with age?

It increases Signup and view all the answers

What is the structureless layer between the epithelium and lamina propria?

Basement membrane Signup and view all the answers

What is the function of the basal lamina?

To act as a barrier to particulate matter Signup and view all the answers

What type of collagen is found in the lamina densa?

Type IV collagen Signup and view all the answers

What is the thickness of the oral epithelium?

0.2-0.3 mm Signup and view all the answers

What is characteristic of the sulcular epithelium?

It is non-keratinized and lacks rete pegs Signup and view all the answers

What is the thickness of the junctional epithelium?

3-4 layers Signup and view all the answers

What is expressed in the junctional epithelium?

K 19 Signup and view all the answers

What is the result of the irregularity of the basement membrane?

All of the above Signup and view all the answers

What is the normal color of the gingiva in adults?

Coral pink Signup and view all the answers

What is the shape of the gingival margin in adults?

Knife edge Signup and view all the answers

What is the consistency of the gingiva in adults?

Firm and resilient Signup and view all the answers

What is the surface texture of the gingiva in adults?

Stippled Signup and view all the answers

What is the normal depth of the gingival sulcus in newly erupted teeth?

2-3 mm Signup and view all the answers

At what age is stippling typically present in the gingiva?

By age 6 Signup and view all the answers

What percentage of connective tissue is formed by collagen fibers?

60% Signup and view all the answers

What is the main function of gingival fibers?

To brace the marginal gingiva firmly against the tooth Signup and view all the answers

What is the main component of the ground substance in connective tissue?

Proteoglycans Signup and view all the answers

What type of fibers provide tensile strength to the lamina propria?

Collagen fibers Signup and view all the answers

What is the origin of the dentogingival group of gingival fibers?

Cementum Signup and view all the answers

What is the main source of blood supply to the gingiva?

All of the above Signup and view all the answers

What is the main cell type responsible for forming collagen and elastic fibers in connective tissue?

Fibroblast Signup and view all the answers

What is the main function of the reticular layer of connective tissue?

To provide a framework for tissue growth Signup and view all the answers

What is the main cell type in the oral epithelium?

Keratinocyte Signup and view all the answers

Where does the proliferation of keratinocytes most frequently occur?

Basal layer Signup and view all the answers

Which type of cell found in the basal layer functions as tactile receptors?

Merkel cells Signup and view all the answers

Which process involves the progressive flattening of the cell and the disappearance of the nucleus?

Keratinization Signup and view all the answers

Which layers are Langerhans cells located in?

Suprabasal layers Signup and view all the answers

What is the turnover time for the gingiva in experimental animals?

10 to 12 days Signup and view all the answers

What is the primary function of gingival epithelium?

Provide a physical barrier to infection Signup and view all the answers

Which cells synthesize melanin?

Melanocytes Signup and view all the answers

Study Notes

Marginal Gingiva

Forms the free edge of the gingiva
Connects the attached gingiva to the tooth
Width: 1-2 mm

Gingival Sulcus

Space between the tooth and the free gingiva
Filled with crevicular fluid
Normal depth: 0-3 mm
Depth increases with inflammation

Attached Gingiva

Part of the gingiva that is firmly attached to the underlying bone
Width decreases with age due to gingival recession

Interdental Gingiva

Shape determined by the shape of the interproximal surfaces of adjacent teeth

Histological Composition of the Gingiva

Epithelium: Oral epithelium and junctional epithelium
Lamina propria: Connective tissue layer

Lamina Propria

Consists of collagen fibers and ground substance
Main cell type: Fibroblast
Composed of reticular and papillary layers

Oral Epithelium

Thickness: 0.2 - 0.5 mm
Four layers: stratum basale, stratum spinosum, stratum granulosum, and stratum corneum
Langerhans cells located in the stratum spinosum and stratum granulosum

Junctional Epithelium

Thickness: 15-30 μm
Epithelium attaches to the tooth via hemidesmosomes
Rich in basal lamina: Connects epithelium to underlying connective tissue
Expressed proteins include: Integrins, cadherins, and desmosomes
Irregularity of the basement membrane: Results in a greater surface area for attachment

Sulcular Epithelium

Characterized by its non-keratinized nature

Gingival Color

Normal color: Pink
Affected by vascularity, pigmentation, and thickness of the epithelium

Gingival Margin

Shape: Crescentic in adults

Gingival Consistency

Firm in adults

Gingival Texture

Orange-peel-like stippling in adults

Gingival Development

Stippling emerges around 6 years of age
Normal sulcus depth in newly erupted teeth: 0-1.5 mm

Collagen Fibers

90% of connective tissue
Main function: Provide support and stability to the gingiva

Ground Substance

Main component: Glycosaminoglycans

Dentogingival Fibers

Origin: Cemento-enamel junction
Insert into: Lamina propria of the gingiva

Blood Supply

Main source: Superior and inferior alveolar arteries

Fibroblasts

Main cell type responsible for collagen and elastic fibers in connective tissue

Reticular Layer of Connective Tissue

Located: Deepest layer of the lamina propria
Contains: Larger blood vessels, nerves, and collagen fibers

Keratinocytes

Main cell type in oral epithelium
Proliferate most frequently in the stratum basale

Merkel Cells

Tactile receptors located in the stratum basale

Keratinization

Process involves: Progressive flattening of the cell and disappearance of the nucleus

Gingival Turnover Time

2-3 weeks in experimental animals

Gingival Epithelium

Primary function: Barrier to infection and injury

Melanocytes

Synthesize melanin: Responsible for gingival pigmentation

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Description

Learn about the normal periodontium, gingiva, and its anatomical divisions, including marginal, attached, and interdental areas. Understand the gingival sulcus and its dimensions.