Dental Anatomy: The Periodontium and Gingiva

The Periodontium

• The periodontium is a functional unit of tissues.
• This unit surrounds and supports the tooth.
• It is made of two parts: the gingiva and the attachment apparatus.
• The gingiva protects the underlying tissues.
• The attachment apparatus consists of the periodontal ligament (PDL), cementum, and alveolar bone.

Clinical and Anatomical Crown and Root

• The Anatomical Crown is the part of the tooth covered by enamel.
• The Anatomical Root is the part of the tooth covered by cementum.
• The Clinical Crown is the part of the tooth that is above the attached periodontal tissue.
• The Clinical Root is the part of the tooth with attached periodontal tissues.

Free Gingiva

• It surrounds the tooth but is not attached to the tooth or alveolar bone.
• It connects with the attached gingiva at the free gingival groove.
• Injury to the periodontium and occlusal trauma can affect the free gingiva.

Gingival Sulcus

• The gingival sulcus is a crevice or space between the free gingiva and the tooth.
• The sulcus extends from the free gingival margin to the JE.

Col

• Col is the depression under the contact area between lingual or palatal and facial papilla.
• It conforms to the proximal contact area and connects the papillae.
• Most gingival diseases start in the col area.

Interdental Gingiva (Interdental Papilla)

• The Interdental gingiva occupies the interproximal area between two adjacent teeth.
• The tip and lateral borders are continuous with the free gingiva.
• Parts of the papilla are attached gingiva.
• The interproximal area is also called an embrasure.

Oral Mucosa

• The oral mucosa is a mucous membrane composed of connective tissue covered with stratified squamous epithelium.
• There are three divisions: Masticatory Mucosa, Lining Mucosa, and Specialized Mucosa.
• Masticatory Mucosa covers the gingiva and hard palate, the areas most used during the mastication of food.
• The normal epithelial covering is keratinized.
• Lining Mucosa covers the inner surfaces of the lips and cheeks, floor of the mouth, the underside of the tongue, soft palate, and alveolar mucosa.
• These tissues are not firmly attached to underlying tissues, and the epithelial covering is not keratinized.
• Specialized Mucosa covers the dorsum (upper surface) of the tongue, and is composed of many papillae; some contain taste buds.

Interdental Embrasure Classifications

• Class I - the interdental papilla is apical to the contact point of adjacent teeth.
• Class II - the interdental papilla is at or apical to the interproximal CEJ.
• Class III - complete loss of the interdental papilla.

Junctional Epithelium

• Cuff-like of stratified squamous epithelium completely encircles the tooth to form a tight seal.
• Provides a seal at the base of the pocket.

Tooth Eruption and the Gingiva

• Before eruption, the oral epithelium covers the tooth.
• As the tooth emerges, the reduced epithelium joins the oral epithelium as the gingival sulcus is formed.
• Partial eruption occurs with the junctional epithelium (JE) along the enamel.
• Eruption is complete with JE at the cementoenamel junction.
• Attachment migrates along the root surface from disease or other cause, exposing the cementum.

Periodontal Ligament

• The periodontal ligament is the fibrous connective tissue that surrounds and attaches the alveolar bone to the cementum.
• It includes the Gingival Fiber Groups, and the Principal Fiber Groups.

Gingival Fiber Groups

• Dentogingival fibers: extend from the cementum in the cervical region into the free gingiva.
• Alveologingival fibers: extend from the alveolar crest into the free and attached gingiva.
• Circumferential fibers: are continuous around the neck of the tooth.
• Dentoperiosteal fibers: extend from the cementum over the alveolar crest.
• Transseptal fibers: extend from the cervical area of one tooth across to an adjacent tooth (on the mesial or distal only).

Principal Fiber Groups

• Apical fibers: extend from the root apex to the adjacent surrounding bone to resist vertical forces.
• Oblique fibers: extend obliquely from the cementum to bone in a coronal direction. They are the majority of the principal fibers helping the tooth to resist vertical and unexpected strong forces.
• Horizontal fibers: extend from the cementum in the middle of each root to the adjacent alveolar bone to resist tipping of the tooth.
• Alveolar crest/Alveologingival fibers: extends from the alveolar crest to the cementum just below the CEJ to resist intrusive forces.
• Interradicular fibers: extend from cementum between the roots of multi-rooted teeth to the adjacent bone to resist vertical and lateral forces.

Cementum

• Cementum is a thin layer of calcified connective tissue.
• Cementum covers the tooth from the CEJ to, and around, the apical foramen.
• It supports the tooth and alveolar bone and serves as the attachment for periodontal fiber groups of the PDL.
• Cementum seals tubules on root dentin.

Alveolar Bone

• Alveolar bone is a specialized part of the mandibular and maxillary bones with a primary function to support the teeth.
• Alveolar bone undergoes rapid and continual remodeling.
• This remodeling is due to the demands of tooth eruption, orthodontic tooth movement, and occlusal forces.

Gingival Tissues

• Factors affecting the gingival tissues include vascular supply, thickness of the epithelium, and the Degree of keratinization.

The Gingival Description

• Signs of Health (pale pink)

The Gingival Description - Bleeding

• Signs of Health: bleeding on probing (NO BOP)
• Changes in Disease: bleeding on probing (BOP)

The Gingival Description - Exudate

• Signs of Health: exudate = no pus
• Changes in Disease: exudate = pus (when probed)

Clefts

• V-shaped Stillman's cleft is a severe form of gingival recession caused by occlusal trauma - it's a triangular indentation
• Slitlike Stillman's cleft is a narrow, slit-like defect in the gum tissue that can appear as a triangular fissure. It is a type of gingival recession that can affect the appearance and health of teeth.
• Floss cleft

Effect of Gingival Recession

• Recession is the exposure of the root surface that results from the apical migration of the JE, which exposes the CEJ.
• Measure the actual recession from the CEJ to the gingival margin.
• Exposed root surface is visible on clinical examination from the gingival margin to the CEJ.

Gingival Hyperplasia

• Gingival Hyperplasia is an abnormal increase of tissue caused by the formation and growth of new normal cells.
• Can be caused by Medicinal use of Phenytoin Cyclosporine Calcium channel blockers Oral contraceptives.

The Gingiva of Young Children

• Gingivitis occurs frequently in children but is usually reversible with improved oral self-care without leaving permanent damage.

Periodontal-Systemic Disease Connection

• Research on the association between periodontal infections and various systemic diseases and conditions.
• Periodontal infections are not shown to directly cause systemic disease.
• Early identification, treatment, and management of periodontal disease is critical.

Periodontal Disease Development

• Periodontitis is characterized by inflammation within the supporting tissues of the teeth.
• It involves progressive destruction of the periodontal ligament, and loss of supporting alveolar bone.
• A pocket is a diseased sulcus.
• Diffuse inflammation is spread out the gingival margin, attached gingiva, and interdental papillae, and may extend into alveolar mucosa.

Risk Assessment consists of Factors:

• Etiologic factor: actual cause
• Predisposing factor: renders a person susceptible
• Contributing factor: lends assistance to, supplements or adds to a condition
• Risk factor: increases the probability that disease will occur

Etiology of Periodontal Disease consists of:

• Microbiomes which are subgingival biofilms.
• These are primary etiologic agents of periodontal disease.
• Diversity and complexity increases in periodontitis.
• Types of organisms shifts to gram-negative anaerobic species.

Risk factors for Periodontal Diseases

• Modifiable - Tobacco Use, Diabetes Mellitus, Obesity, Alcohol Consumption, Diet, Psychological Factors, and Medications.

Nonmodifiable Risk Factors

• Genetic Predisposition, Host Response, Osteoporosis, and Age.

Local Factors

• Dental Factors, Tooth Surface Irregularities, Tooth Contour, Position, and Dental Appliances.
• Gingival Factors: Position, Size and contour, and Effect of Mouth Breathing.
• Other Factors: Person Oral Self Care and Diet/Eating Habits.

Pathogenesis of Periodontal Diseases

• Pathogenesis is the process by which a disease develops and progresses.
• The primary etiology of periodontal disease is bacteria that initiate an inflammatory process.

Development of Gingival and Periodontal Infection:

• Initial Lesion: No clinical evidence or change/Inflammation response to dental biofilm
• Early Lesion: Biofilm becomes older and thicker
• Established Lesion: Proliferation of the JE and sulcus continues
• Advanced Lesion: Diseased cementum contains a thin superficial layer of endotoxins from the bacterial breakdown/BOP

Types of Pockets:

• Have inner and outer walls
• Can contain substances such as microorganisms, gingival crevicular fluid, and desquamated epithelial cells
• Divided into gingival and periodontal types

Gingival and Periodontal Pockets are defined as:

• Gingival Pocket or Pseudopocket: A pocket formed by gingival enlargement without apical migration of the junctional epithelium

• Periodontal Pocket: A pocket formed as a result of disease or degeneration, causing apical migration of the junctional epithelium along the cementum.

Complications Resulting from Periodontal Disease Progression

• Furcation Involvement can be determined by clinical Observations and using a Nabers Probe.
• A mucogingival Involvement demonstrates significance is attached Gingiva that affects a pocket that extends to or beyond the mucogingival junction and into the alveolar mucosa.

Methods of Recognition of Gingival and Periodontal Infections are defined through

• Clinical Examination
• Gingival tissue changes
• Mucogingival involvement
• Probing depths
• Clinical attachment levels
• Bleeding on probing
• Exudate or suppuration
• Furcation involvement
• Dental biofilm and calculus distribution
• Tooth mobility
• Radiographic evaluation