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Periodontology

Influence of Host Response on Periodontal Disease

The host response plays a critical role in the progression and management of periodontal disease. Various host factors influence bacterial colonization, invasion, tissue destruction, and healing processes. Understanding these interactions is essential for developing effective treatment strategies.

Aspects of Periodontal Disease and Host Factors

  1. Bacterial Colonization:

    • Host Factor: Antibody C in crevicular fluid.
    • Mechanism:
      • Antibody C inhibits the adherence and coaggregation of bacteria in the subgingival environment.
      • This action potentially reduces bacterial numbers by promoting lysis (destruction of bacterial cells).
    • Implication: A robust antibody response can help control the initial colonization of pathogenic bacteria, thereby influencing the onset of periodontal disease.
  2. Bacterial Invasion:

    • Host Factor: Antibody C-mediated lysis and neutrophil activity.
    • Mechanism:
      • Antibody C-mediated lysis reduces bacterial counts in the periodontal tissues.
      • Neutrophils, through processes such as chemotaxis (movement towards chemical signals), phagocytosis (engulfing and digesting bacteria), and lysis, further reduce bacterial counts.
    • Implication: An effective neutrophil response is crucial for controlling bacterial invasion and preventing the progression of periodontal disease.
  3. Tissue Destruction:

    • Host Factors: Antibody-mediated hypersensitivity and cell-mediated immune responses.
    • Mechanism:
      • Activation of tissue factors, such as collagenase, leads to the breakdown of connective tissue and periodontal structures.
      • The immune response can inadvertently contribute to tissue destruction, as inflammatory mediators can damage host tissues.
    • Implication: While the immune response is essential for fighting infection, it can also lead to collateral damage in periodontal tissues, exacerbating disease progression.
  4. Healing and Fibrosis:

    • Host Factors: Lymphocytes and macrophage-produced chemotactic factors.
    • Mechanism:
      • Lymphocytes and macrophages release chemotactic factors that attract fibroblasts to the site of injury.
      • Fibroblasts are activated by specific factors, promoting tissue repair and fibrosis (the formation of excess connective tissue).
    • Implication: A balanced immune response is necessary for effective healing and regeneration of periodontal tissues following inflammation.

Stippling of the Gingiva

  • Stippling refers to the textured surface of the gingiva that resembles the skin of an orange. This characteristic is best observed when the gingiva is dried.

  • Characteristics:

    • Location:
      • The attached gingiva is typically stippled, while the marginal gingiva is not.
      • The central portion of the interdental gingiva may exhibit stippling, but its marginal borders are usually smooth.
    • Surface Variation:
      • Stippling is generally less prominent on the lingual surfaces compared to the facial surfaces and may be absent in some individuals.
    • Age-Related Changes:
      • Stippling is absent in infancy, begins to appear around 5 years of age, increases until adulthood, and may start to disappear in old age.

Attached Gingiva

  • Definition: The attached gingiva is the portion of the gingiva that is firmly bound to the underlying alveolar bone and extends from the free gingival groove to the mucogingival junction, where it meets the alveolar mucosa.

  • Characteristics:

    • Structure:
      • The attached gingiva is classified as a mucoperiosteum, tightly bound to the underlying alveolar bone.
    • Width:
      • The width of the attached gingiva is greatest in the incisor region, measuring approximately:
        • 3.5 � 4.5 mm in the maxilla
        • 3.3 � 3.9 mm in the mandible
      • It is narrower in the posterior segments, measuring about:
        • 1.9 mm in the maxillary first premolars
        • 1.8 mm in the mandibular first premolars.
    • Histological Features:
      • The attached gingiva is thick and keratinized (or parakeratinized) and is classified as masticatory mucosa.
      • Masticatory mucosa is characterized by a keratinized epithelium and a thick lamina propria, providing resistance to mechanical forces.

Masticatory vs. Lining Mucosa

  • Masticatory Mucosa:

    • Found in areas subject to high compression and friction, such as the gingiva and hard palate.
    • Characterized by keratinized epithelium and a thick lamina propria, making it resistant to masticatory forces.
  • Lining Mucosa:

    • Mobile, distensible, and non-keratinized.
    • Found in areas such as the lips, cheeks, alveolus, floor of the mouth, ventral surface of the tongue, and soft palate.
  • Specialized Mucosa:

    • Found on the dorsum of the tongue, adapted for specific functions such as taste.

Flossing Technique

Flossing is an essential part of oral hygiene that helps remove plaque and food particles from between the teeth and along the gumline, areas that toothbrushes may not effectively clean. Proper flossing technique is crucial for maintaining gum health and preventing cavities.

Flossing Technique

  1. Preparation:

    • Length of Floss: Take 12 to 18 inches of dental floss. This length allows for adequate maneuverability and ensures that you can use a clean section of floss for each tooth.
    • Grasping the Floss: Hold the floss taut between your hands, leaving a couple of inches of floss between your fingers. This tension helps control the floss as you maneuver it between your teeth.
  2. Inserting the Floss:

    • Slip Between Teeth: Gently slide the floss between your teeth. Be careful not to snap the floss, as this can cause trauma to the gums.
    • Positioning: Insert the floss into the area between your teeth and gums as far as it will comfortably go, ensuring that you reach the gumline.
  3. Flossing Motion:

    • Vertical Strokes: Use 8 to 10 vertical strokes with the floss to dislodge food particles and plaque. Move the floss up and down against the sides of each tooth, making sure to clean both the front and back surfaces.
    • C-Shaped Motion: For optimal cleaning, wrap the floss around the tooth in a C-shape and gently slide it beneath the gumline.
  4. Frequency:

    • Daily Flossing: Aim to floss at least once a day. Consistency is key to maintaining good oral hygiene.
    • Best Time to Floss: The most important time to floss is before going to bed, as this helps remove debris and plaque that can accumulate throughout the day.
  5. Flossing and Brushing:

    • Order of Operations: Flossing can be done either before or after brushing your teeth. Both methods are effective, so choose the one that fits best into your routine.

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

Dental Calculus

Dental calculus, also known as tartar, is a hard deposit that forms on teeth due to the mineralization of dental plaque. Understanding the composition and crystal forms of calculus is essential for dental professionals in diagnosing and managing periodontal disease.

Crystal Forms in Dental Calculus

  1. Common Crystal Forms:

    • Dental calculus typically contains two or more crystal forms. The most frequently detected forms include:
      • Hydroxyapatite:
        • This is the primary mineral component of both enamel and calculus, constituting a significant portion of the calculus sample.
        • Hydroxyapatite is a crystalline structure that provides strength and stability to the calculus.
      • Octacalcium Phosphate:
        • Detected in a high percentage of supragingival calculus samples (97% to 100%).
        • This form is also a significant contributor to the bulk of calculus.
  2. Other Crystal Forms:

    • Brushite:
      • More commonly found in the mandibular anterior region of the mouth.
      • Brushite is a less stable form of calcium phosphate and may indicate a younger calculus deposit.
    • Magnesium Whitlockite:
      • Typically found in the posterior areas of the mouth.
      • This form may be associated with older calculus deposits and can indicate changes in the mineral composition over time.
  3. Variation with Age:

    • The incidence and types of crystal forms present in calculus can vary with the age of the deposit.
    • Younger calculus deposits may have a higher proportion of brushite, while older deposits may show a predominance of hydroxyapatite and magnesium whitlockite.

Clinical Significance

  1. Understanding Calculus Formation:

    • Knowledge of the crystal forms in calculus can help dental professionals understand the mineralization process and the conditions under which calculus forms.
  2. Implications for Treatment:

    • The composition of calculus can influence treatment strategies. For example, older calculus deposits may be more difficult to remove due to their hardness and mineral content.
  3. Assessment of Periodontal Health:

    • The presence and type of calculus can provide insights into a patient�s oral hygiene practices and periodontal health. Regular monitoring and removal of calculus are essential for preventing periodontal disease.
  4. Research and Development:

    • Understanding the mineral composition of calculus can aid in the development of new dental materials and treatments aimed at preventing calculus formation and promoting oral health.

Epithelial Turnover Rates in Oral Tissues

Epithelial turnover is a critical process in maintaining the health and integrity of oral tissues. Understanding the turnover rates of different epithelial types in the oral cavity can provide insights into their regenerative capabilities and responses to injury or disease.

Turnover Rates of Oral Epithelial Tissues

  1. Junctional Epithelium:

    • Turnover Rate1-6 days
    • Description:
      • The junctional epithelium is a specialized epithelial tissue that forms the attachment between the gingiva and the tooth surface.
      • Its rapid turnover rate is essential for maintaining a healthy seal around the tooth and for responding quickly to inflammatory changes or injury.
  2. Palate, Tongue, and Cheeks:

    • Turnover Rate5-6 days
    • Description:
      • The epithelial tissues of the hard palate, tongue, and buccal mucosa (cheeks) have a moderate turnover rate.
      • This relatively quick turnover helps maintain the integrity of these surfaces, which are subject to mechanical stress and potential injury from food and other environmental factors.
  3. Gingiva:

    • Turnover Rate10-12 days
    • Description:
      • The gingival epithelium has a slower turnover rate compared to the junctional epithelium and the epithelium of the palate, tongue, and cheeks.
      • This slower rate reflects the need for stability in the gingival tissue, which plays a crucial role in supporting the teeth and maintaining periodontal health.

Clinical Significance

  • Wound Healing:

    • The rapid turnover of the junctional epithelium is particularly important in the context of periodontal health, as it allows for quick healing of any disruptions caused by inflammation or mechanical trauma.
  • Response to Disease:

    • Understanding the turnover rates can help clinicians anticipate how quickly tissues may respond to treatment or how they may regenerate after surgical procedures.
  • Oral Health Maintenance:

    • The varying turnover rates highlight the importance of maintaining good oral hygiene practices to support the health of these tissues, especially in areas with slower turnover rates like the gingiva.

Periodontal Bone Grafts

Bone grafting is a critical procedure in periodontal surgery, aimed at restoring lost bone and supporting the regeneration of periodontal tissues.

1. Bone Blend

 Bone blend is a mixture of cortical or cancellous bone that is procured using a trephine or rongeurs, placed in an amalgam capsule, and triturated to achieve a slushy osseous mass. This technique allows for the creation of smaller particle sizes, which enhances resorption and replacement with host bone.

Particle Size: The ideal particle size for bone blend is approximately 210 x 105 micrometers.

Rationale: Smaller particle sizes improve the chances of resorption and integration with the host bone, making the graft more effective.

2. Types of Periodontal Bone Grafts

A. Autogenous Grafts

Autogenous grafts are harvested from the patient�s own body, providing the best compatibility and healing potential.

  1. Cortical Bone Chips

    • History: First used by Nabers and O'Leary in 1965.
    • Characteristics: Composed of shavings of cortical bone removed during osteoplasty and ostectomy from intraoral sites.
    • Challenges: Larger particle sizes can complicate placement and handling, and there is a potential for sequestration. This method has largely been replaced by autogenous osseous coagulum and bone blend.
  2. Osseous Coagulum and Bone Blend

    • Technique: Intraoral bone is obtained using high- or low-speed round burs and mixed with blood to form an osseous coagulum (Robinson, 1969).
    • Advantages: Overcomes disadvantages of cortical bone chips, such as inability to aspirate during collection and variability in quality and quantity of collected bone.
    • Applications: Used in various periodontal procedures to enhance healing and regeneration.
  3. Intraoral Cancellous Bone and Marrow

    • Sources: Healing bony wounds, extraction sockets, edentulous ridges, mandibular retromolar areas, and maxillary tuberosity.
    • Applications: Provides a rich source of osteogenic cells and growth factors for bone regeneration.
  4. Extraoral Cancellous Bone and Marrow

    • Sources: Obtained from the anterior or posterior iliac crest.
    • Advantages: Generally offers the greatest potential for new bone growth due to the abundance of cancellous bone and marrow.

B. Bone Allografts

Bone allografts are harvested from donors and can be classified into three main types:

  1. Undermineralized Freeze-Dried Bone Allograft (FDBA)

    • Introduction: Introduced in 1976 by Mellonig et al.
    • Process: Freeze drying removes approximately 95% of the water from bone, preserving morphology, solubility, and chemical integrity while reducing antigenicity.
    • Efficacy: FDBA combined with autogenous bone is more effective than FDBA alone, particularly in treating furcation involvements.
  2. Demineralized (Decalcified) FDBA

    • Mechanism: Demineralization enhances osteogenic potential by exposing bone morphogenetic proteins (BMPs) in the bone matrix.
    • Osteoinduction vs. Osteoconduction: Demineralized grafts induce new bone formation (osteoinduction), while undermineralized allografts facilitate bone growth by providing a scaffold (osteoconduction).
  3. Frozen Iliac Cancellous Bone and Marrow

    • Usage: Used sparingly due to variability in outcomes and potential complications.

Comparison of Allografts and Alloplasts

  • Clinical Outcomes: Both FDBA and DFDBA have been compared to porous particulate hydroxyapatite, showing little difference in post-treatment clinical parameters.
  • Histological Healing: Grafts of DFDBA typically heal with regeneration of the periodontium, while synthetic bone grafts (alloplasts) heal by repair, which may not restore the original periodontal architecture.

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