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Periodontology - NEETMDS- courses
NEET MDS Lessons
Periodontology

Zones of Periodontal Disease

Listgarten described four distinct zones that can be observed in periodontal lesions. These zones may blend with each other and may not be present in every case.

Zones of Periodontal Disease

  1. Zone 1: Bacterial Zone

    • Description: This is the most superficial zone, consisting of a diverse array of bacteria.
    • Characteristics:
      • The bacterial zone is primarily composed of various microbial species, including both pathogenic and non-pathogenic bacteria.
      • This zone is critical in the initiation and progression of periodontal disease, as the presence of specific bacteria can trigger inflammatory responses in the host.
  2. Zone 2: Neutrophil Rich Zone

    • Description: This zone contains numerous leukocytes, predominantly neutrophils.
    • Characteristics:
      • The neutrophil-rich zone is indicative of the body’s immune response to the bacterial invasion.
      • Neutrophils are the first line of defense and play a crucial role in phagocytosing bacteria and releasing inflammatory mediators.
      • The presence of a high number of neutrophils suggests an acute inflammatory response, which is common in active periodontal disease.
  3. Zone 3: Necrotic Zone

    • Description: This zone consists of disintegrated tissue cells, fibrillar material, remnants of collagen fibers, and spirochetes.
    • Characteristics:
      • The necrotic zone reflects tissue destruction and is characterized by the presence of dead or dying cells.
      • Fibrillar material and remnants of collagen fibers indicate the breakdown of the extracellular matrix, which is essential for maintaining periodontal tissue integrity.
      • Spirochetes, which are associated with more aggressive forms of periodontal disease, can also be found in this zone, contributing to the necrotic process.
  4. Zone 4: Zone of Spirochetal Infiltration

    • Description: This zone consists of well-preserved tissue that is infiltrated with large and medium spirochetes.
    • Characteristics:
      • The zone of spirochetal infiltration indicates a more chronic phase of periodontal disease, where spirochetes invade the connective tissue.
      • The presence of well-preserved tissue suggests that while spirochetes are present, the tissue has not yet undergone extensive necrosis.
      • This zone is significant as it highlights the role of spirochetes in the pathogenesis of periodontal disease, particularly in cases of necrotizing periodontal diseases.

Classification of Periodontal Pockets

Periodontal pockets are an important aspect of periodontal disease, reflecting the health of the supporting structures of the teeth. Understanding the classification of these pockets is essential for diagnosis, treatment planning, and management of periodontal conditions.

Classification of Pockets

  1. Gingival Pocket:

    • Also Known As: Pseudo-pocket.
    • Formation:
      • Formed by gingival enlargement without destruction of the underlying periodontal tissues.
      • The sulcus is deepened due to the increased bulk of the gingiva.
    • Characteristics:
      • There is no destruction of the supporting periodontal tissues.
      • Typically associated with conditions such as gingival hyperplasia or inflammation.
  2. Periodontal Pocket:

    • Definition: A pocket that results in the destruction of the supporting periodontal tissues, leading to the loosening and potential exfoliation of teeth.
    • Classification Based on Location:
      • Suprabony Pocket:
        • The base of the pocket is coronal to the alveolar bone.
        • The pattern of bone destruction is horizontal.
        • The transseptal fibers are arranged horizontally in the space between the base of the pocket and the alveolar bone.
      • Infrabony Pocket:
        • The base of the pocket is apical to the alveolar bone, meaning the pocket wall lies between the bone and the tooth.
        • The pattern of bone destruction is vertical.
        • The transseptal fibers are oblique rather than horizontal.

Classification of Periodontal Pockets

  1. Suprabony Pocket (Supracrestal or Supraalveolar):

    • Location: Base of the pocket is coronal to the alveolar bone.
    • Bone Destruction: Horizontal pattern of bone loss.
    • Transseptal Fibers: Arranged horizontally.
  2. Infrabony Pocket (Intrabony, Subcrestal, or Intraalveolar):

    • Location: Base of the pocket is apical to the alveolar bone.
    • Bone Destruction: Vertical pattern of bone loss.
    • Transseptal Fibers: Arranged obliquely.

Classification of Pockets According to Involved Tooth Surfaces

  1. Simple Pocket:

    • Definition: Involves only one tooth surface.
    • Example: A pocket that is present only on the buccal surface of a tooth.
  2. Compound Pocket:

    • Definition: A pocket present on two or more surfaces of a tooth.
    • Example: A pocket that involves both the buccal and lingual surfaces.
  3. Spiral Pocket:

    • Definition: Originates on one tooth surface and twists around the tooth to involve one or more additional surfaces.
    • Example: A pocket that starts on the mesial surface and wraps around to the distal surface.

Classification of Cementum According to Schroeder

Cementum is a specialized calcified tissue that covers the roots of teeth and plays a crucial role in periodontal health. According to Schroeder, cementum can be classified into several distinct types based on its cellular composition and structural characteristics. Understanding these classifications is essential for dental professionals in diagnosing and treating periodontal conditions.

Classification of Cementum

  1. Acellular Afibrillar Cementum:

    • Characteristics:
      • Contains neither cells nor collagen fibers.
      • Present in the coronal region of the tooth.
      • Thickness ranges from 1 µm to 15 µm.
    • Function:
      • This type of cementum is thought to play a role in the attachment of the gingiva to the tooth surface.
  2. Acellular Extrinsic Fiber Cementum:

    • Characteristics:
      • Lacks cells but contains closely packed bundles of Sharpey’s fibers, which are collagen fibers that anchor the cementum to the periodontal ligament.
      • Typically found in the cervical third of the roots.
      • Thickness ranges from 30 µm to 230 µm.
    • Function:
      • Provides strong attachment of the periodontal ligament to the tooth, contributing to the stability of the tooth in its socket.
  3. Cellular Mixed Stratified Cementum:

    • Characteristics:
      • Contains both extrinsic and intrinsic fibers and may contain cells.
      • Found in the apical third of the roots, at the apices, and in furcation areas.
      • Thickness ranges from 100 µm to 1000 µm.
    • Function:
      • This type of cementum is involved in the repair and adaptation of the tooth root, especially in response to functional demands and periodontal disease.
  4. Cellular Intrinsic Fiber Cementum:

    • Characteristics:
      • Contains cells but no extrinsic collagen fibers.
      • Primarily fills resorption lacunae, which are areas where cementum has been resorbed.
    • Function:
      • Plays a role in the repair of cementum and may be involved in the response to periodontal disease.
  5. Intermediate Cementum:

    • Characteristics:
      • A poorly defined zone located near the cementoenamel junction (CEJ) of certain teeth.
      • Appears to contain cellular remnants of the Hertwig's epithelial root sheath (HERS) embedded in a calcified ground substance.
    • Function:
      • Its exact role is not fully understood, but it may be involved in the transition between enamel and cementum.

Clinical Significance

  • Importance of Cementum:

    • Understanding the different types of cementum is crucial for diagnosing periodontal diseases and planning treatment strategies.
    • The presence of various types of cementum can influence the response of periodontal tissues to disease and trauma.
  • Cementum in Periodontal Disease:

    • Changes in the thickness and composition of cementum can occur in response to periodontal disease, affecting tooth stability and attachment.

Pathogens Implicated in Periodontal Diseases

Periodontal diseases are associated with a variety of pathogenic microorganisms. Below is a list of key pathogens implicated in different forms of periodontal disease, along with their associations:

General Pathogens Associated with Periodontal Diseases

  • Actinobacillus actinomycetemcomitans:

    • Strongly associated with destructive periodontal disease.
  • Porphyromonas gingivalis:

    • A member of the "black pigmented Bacteroides group" and a significant contributor to periodontal disease.
  • Bacteroides forsythus:

    • Associated with chronic periodontitis.
  • Spirochetes (Treponema denticola):

    • Implicated in various periodontal conditions.
  • Prevotella intermedia/nigrescens:

    • Also belongs to the "black pigmented Bacteroides group" and is associated with several forms of periodontal disease.
  • Fusobacterium nucleatum:

    • Plays a role in the progression of periodontal disease.
  • Campylobacter rectus:

    • These organisms include members of the new genus Wolinella and are associated with periodontal disease.

Principal Bacteria Associated with Specific Periodontal Diseases

  1. Adult Periodontitis:

    • Porphyromonas gingivalis
    • Prevotella intermedia
    • Bacteroides forsythus
    • Campylobacter rectus
  2. Refractory Periodontitis:

    • Bacteroides forsythus
    • Porphyromonas gingivalis
    • Campylobacter rectus
    • Prevotella intermedia
  3. Localized Juvenile Periodontitis (LJP):

    • Actinobacillus actinomycetemcomitans
    • Capnocytophaga
  4. Periodontitis in Juvenile Diabetes:

    • Capnocytophaga
    • Actinobacillus actinomycetemcomitans
  5. Pregnancy Gingivitis:

    • Prevotella intermedia
  6. Acute Necrotizing Ulcerative Gingivitis (ANUG):

    • Prevotella intermedia
    • Intermediate-sized spirochetes

Classification of Embrasures

  1. Type I Embrasures:

    • Description: These are characterized by the presence of interdental papillae that completely fill the embrasure space, with no gingival recession.
    • Recommended Cleaning Device:
      • Dental Floss: Dental floss is most effective in cleaning Type I embrasures. It can effectively remove plaque and debris from the tight spaces between teeth.
  2. Type II Embrasures:

    • Description: These embrasures have larger spaces due to some loss of attachment, but the interdental papillae are still present.
    • Recommended Cleaning Device:
      • Interproximal Brush: For Type II embrasures, interproximal brushes are recommended. These brushes have bristles that can effectively clean around the exposed root surfaces and between teeth, providing better plaque removal than dental floss in these larger spaces.
  3. Type III Embrasures:

    • Description: These spaces occur when there is significant loss of attachment, resulting in the absence of interdental papillae.
    • Recommended Cleaning Device:
      • Single Tufted Brushes: Single tufted brushes (also known as end-tuft brushes) are ideal for cleaning Type III embrasures. They can reach areas that are difficult to access with traditional floss or brushes, effectively cleaning the exposed root surfaces and the surrounding areas.

Periodontal Medicaments

Periodontal diseases often require adjunctive therapies to traditional mechanical treatments such as scaling and root planing. Various medicaments have been developed to enhance the healing process and control infection in periodontal tissues. This lecture will discuss several periodontal medicaments, their compositions, and their clinical applications.

1. Elyzol

  • Composition:
    • Elyzol is an oil-based gel containing 25% metronidazole. It is formulated with glyceryl mono-oleate and sesame oil.
  • Clinical Use:
    • Elyzol has been found to be equivalent to scaling and root planing in terms of effectiveness for treating periodontal disease.
    • However, no adjunctive effects beyond those achieved with mechanical debridement have been demonstrated.

2. Actisite

  • Composition:

    • Actisite consists of tetracycline-containing fibers.
    • Each fiber has a diameter of 0.5 mm and contains 12.7 mg of tetracycline per 9 inches of fiber.
  • Clinical Use:

    • The fibers are placed directly into periodontal pockets, where they release tetracycline over time, helping to reduce bacterial load and promote healing.

3. Arestin

  • Composition:

    • Arestin contains minocycline, which is delivered as a biodegradable powder in a syringe.
  • Clinical Use:

    • Arestin is indicated for the treatment of periodontal disease and is applied directly into periodontal pockets, where it provides localized antibiotic therapy.

4. Atridox

  • Composition:

    • Atridox contains 10% doxycycline in a syringeable gel system that is biodegradable.
  • Clinical Use:

    • The gel is injected into periodontal pockets, where it solidifies and releases doxycycline over time, aiding in the management of periodontal disease.

5. Dentamycin and Periocline

  • Composition:

    • Both Dentamycin and Periocline contain 2% minocycline hydrochloride.
  • Clinical Use:

    • These products are used similarly to other local delivery systems, providing localized antibiotic therapy to reduce bacterial infection in periodontal pockets.

6. Periochip

  • Composition:

    • Periochip is a biodegradable chip that contains chlorhexidine.
  • Clinical Use:

    • The chip is placed in the gingival crevice, where it releases chlorhexidine over time, providing antimicrobial action and helping to control periodontal disease.

Transforming Growth Factor-Beta (TGF-β)

Transforming Growth Factor-Beta (TGF-β) is a multifunctional cytokine that plays a critical role in various biological processes, including development, tissue repair, immune regulation, and inflammation. Understanding its functions and mechanisms is essential for appreciating its significance in health and disease.

Overview of TGF-β

  1. Half-Life:

    • Active TGF-β has a very short half-life of approximately 2 minutes. This rapid turnover is crucial for its role in dynamic biological processes.
  2. Functions:

    • TGF-β is involved in several key physiological and pathological processes:
      • Development: Plays a vital role in embryonic development and organogenesis.
      • Tissue Repair: Promotes wound healing and tissue regeneration by stimulating the proliferation and differentiation of various cell types.
      • Immune Defense: Modulates immune responses, influencing the activity of immune cells.
      • Inflammation: Regulates inflammatory processes, contributing to both pro-inflammatory and anti-inflammatory responses.
      • Tumorigenesis: Involved in cancer progression, where it can have both tumor-suppressive and tumor-promoting effects depending on the context.
  3. Cellular Effects:

    • Stimulates:
      • Osteoblasts: Promotes the differentiation and activity of osteoblasts, which are responsible for bone formation.
      • Fibroblasts: Enhances the proliferation and activity of fibroblasts, contributing to extracellular matrix production and tissue repair.
    • Inhibits:
      • Osteoclasts: Suppresses the activity of osteoclasts, which are responsible for bone resorption.
      • Epithelial Cells: Inhibits the proliferation of epithelial cells, affecting tissue homeostasis.
      • Most Immune Cells: Generally inhibits the activation and proliferation of various immune cells, contributing to its immunosuppressive effects.
  4. Production and Activation:

    • TGF-β is produced as an inactive propeptide (latent form) and requires activation to become biologically active.
    • Activation Conditions: The activation of TGF-β typically requires acidic conditions, which can occur in various physiological and pathological contexts, such as during inflammation or tissue injury.

Clinical Implications

  1. Wound Healing:

    • TGF-β is crucial for effective wound healing and tissue repair, making it a target for therapeutic interventions in regenerative medicine.
  2. Bone Health:

    • Its role in stimulating osteoblasts makes TGF-β important in bone health and diseases such as osteoporosis.
  3. Cancer:

    • The dual role of TGF-β in tumorigenesis highlights its complexity; it can act as a tumor suppressor in early stages but may promote tumor progression in later stages.
  4. Autoimmune Diseases:

    • Due to its immunosuppressive properties, TGF-β is being studied for its potential in treating autoimmune diseases and in transplant medicine to prevent rejection.

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