Localized Aggressive Periodontitis and Necrotizing Ulcerative Gingivitis

Localized Aggressive Periodontitis (LAP)

Localized aggressive periodontitis, previously known as localized juvenile periodontitis, is characterized by specific microbial profiles and clinical features.

• Microbiota Composition:
  • The microbiota associated with LAP is predominantly composed of:
    • Gram-Negative, Capnophilic, and Anaerobic Rods.
  • Key Organisms:
    • Actinobacillus actinomycetemcomitans: The main organism involved in LAP.
    • Other significant organisms include:
      • Porphyromonas gingivalis
      • Eikenella corrodens
      • Campylobacter rectus
      • Bacteroides capillus
      • Spirochetes (various species).
  • Viral Associations:
    • Herpes viruses, including Epstein-Barr Virus-1 (EBV-1) and Human Cytomegalovirus (HCMV), have also been associated with LAP.

Necrotizing Ulcerative Gingivitis (NUG)

• Microbial Profile:
  • NUG is characterized by high levels of:
    • Prevotella intermedia
    • Spirochetes (various species).
• Clinical Features:
  • NUG presents with necrosis of the gingival tissue, pain, and ulceration, often accompanied by systemic symptoms.

Microbial Shifts in Periodontal Disease

When comparing the microbiota across different states of periodontal health, a distinct microbial shift can be identified as the disease progresses from health to gingivitis to periodontitis:

1. From Gram-Positive to Gram-Negative:

   • Healthy gingival sites are predominantly colonized by gram-positive bacteria, while diseased sites show an increase in gram-negative bacteria.

2. From Cocci to Rods (and Later to Spirochetes):

   • In health, cocci (spherical bacteria) are prevalent. As the disease progresses, there is a shift towards rod-shaped bacteria, and in advanced stages, spirochetes become more prominent.

3. From Non-Motile to Motile Organisms:

   • Healthy sites are often dominated by non-motile bacteria, while motile organisms increase in number as periodontal disease develops.

4. From Facultative Anaerobes to Obligate Anaerobes:

   • In health, facultative anaerobes (which can survive with or without oxygen) are common. In contrast, obligate anaerobes (which thrive in the absence of oxygen) become more prevalent in periodontal disease.

5. From Fermenting to Proteolytic Species:

   • The microbial community shifts from fermentative bacteria, which primarily metabolize carbohydrates, to proteolytic species that break down proteins, contributing to tissue destruction and inflammation.

Components of Gingival Crevicular Fluid (GCF) and Matrix Metalloproteinases (MMPs)

Gingival crevicular fluid (GCF) is a serum-like fluid found in the gingival sulcus that plays a significant role in periodontal health and disease. Understanding its composition, particularly glucose and protein content, as well as the role of matrix metalloproteinases (MMPs) in tissue remodeling, is essential for dental professionals.

Composition of Gingival Crevicular Fluid (GCF)

1. Glucose and Hexosamines:

   • GCF contains compounds such as glucose, hexosamines, and hexuronic acid.
   • Glucose Levels:
     • Blood glucose levels do not correlate with GCF glucose levels; in fact, glucose concentration in GCF is three to four times greater than that in serum.
     • This elevated glucose level is interpreted as a result of the metabolic activity of adjacent tissues and the influence of local microbial flora.

2. Protein Content:

   • The total protein content of GCF is significantly less than that of serum.
   • This difference in protein concentration reflects the unique environment of the gingival sulcus and the specific functions of GCF in periodontal health.

Matrix Metalloproteinases (MMPs)

1. Definition and Function:

   • MMPs are a family of proteolytic enzymes that degrade extracellular matrix molecules, including collagen, gelatin, and elastin.
   • They are produced by various cell types, including:
     • Neutrophils
     • Macrophages
     • Fibroblasts
     • Epithelial cells
     • Osteoblasts and osteoclasts

2. Classification:

   • MMPs are classified based on their substrate specificity, although it is now recognized that many MMPs can degrade multiple substrates. The classification includes:
     • Collagenases: e.g., MMP-1 and MMP-8 (break down collagen)
     • Gelatinases: Type IV collagenases
     • Stromelysins
     • Matrilysins
     • Membrane-type metalloproteinases
     • Others

3. Activation and Inhibition:

   • MMPs are secreted in an inactive form (latent) and require proteolytic cleavage for activation. This activation is facilitated by proteases such as cathepsin G produced by neutrophils.
   • Inhibitors: MMPs are regulated by proteinase inhibitors, which possess anti-inflammatory properties. Key inhibitors include:
     • Serum Inhibitors:
       • α1-antitrypsin
       • α2-macroglobulin (produced by the liver, inactivates various proteinases)
     • Tissue Inhibitors:
       • Tissue inhibitors of metalloproteinases (TIMPs), with TIMP-1 being particularly important in periodontal disease.
   • Antibiotic Inhibition: MMPs can also be inhibited by tetracycline antibiotics, leading to the development of sub-antimicrobial formulations of doxycycline as a systemic adjunctive treatment for periodontitis, exploiting its anti-MMP properties.

Merkel Cells

1. Location and Function:
   • Merkel cells are located in the deeper layers of the epithelium and are associated with nerve endings.
   • They are connected to adjacent cells by desmosomes and are identified as tactile receptors.
   • These cells play a role in the sensation of touch and pressure, contributing to the sensory functions of the oral mucosa.

Clinical Implications

1. GCF Analysis:

   • The composition of GCF, including glucose and protein levels, can provide insights into the inflammatory status of the periodontal tissues and the presence of periodontal disease.

2. Role of MMPs in Periodontal Disease:

   • MMPs are involved in the remodeling of periodontal tissues during inflammation and disease progression. Understanding their regulation and activity is crucial for developing therapeutic strategies.

3. Therapeutic Applications:

   • The use of sub-antimicrobial doxycycline as an adjunctive treatment for periodontitis highlights the importance of MMP inhibition in managing periodontal disease.

4. Sensory Function:

   • The presence of Merkel cells in the gingival epithelium underscores the importance of sensory feedback in maintaining oral health and function.

Some important points about the periodontal pocket :
·Soft tissue of pocket wall shows both proliferative & degenerative changes
·Most severe degenerative changes are seen on the lateral wall of pocket
·Plasma cells are the predominant infiltrate (80%). Others include lymphocytes & a scattering of PMNs
·Height of junctional epithelium shortened to only 50-100µm
·Severity of degenerative changes is not linked to pocket depth
·Junctional epithelium starts to lose attachment to tooth when PMN infiltration in junctional epithelium increases above 60%.

Acquired Pellicle in the Oral Cavity

The acquired pellicle is a crucial component of oral health, serving as the first line of defense in the oral cavity and playing a significant role in the initial stages of biofilm formation on tooth surfaces. Understanding the composition, formation, and function of the acquired pellicle is essential for dental professionals in managing oral health.

Composition of the Acquired Pellicle

1. Definition:

   • The acquired pellicle is a thin, organic layer that coats all surfaces in the oral cavity, including both hard (tooth enamel) and soft tissues (gingiva, mucosa).

2. Components:

   • The pellicle consists of more than 180 peptides, proteins, and glycoproteins, which include:
     • Keratins: Structural proteins that provide strength.
     • Mucins: Glycoproteins that contribute to the viscosity and protective properties of saliva.
     • Proline-rich proteins: Involved in the binding of calcium and phosphate.
     • Phosphoproteins: Such as statherin, which helps in maintaining calcium levels and preventing mineral loss.
     • Histidine-rich proteins: May play a role in buffering and mineralization.
   • These components function as adhesion sites (receptors) for bacteria, facilitating the initial colonization of tooth surfaces.

Formation and Maturation of the Acquired Pellicle

1. Rapid Formation:

   • The salivary pellicle can be detected on clean enamel surfaces within 1 minute after exposure to saliva. This rapid formation is crucial for protecting the enamel and providing a substrate for bacterial adhesion.

2. Equilibrium State:

   • By 2 hours, the pellicle reaches a state of equilibrium between adsorption (the process of molecules adhering to the surface) and detachment. This dynamic balance allows for the continuous exchange of molecules within the pellicle.

3. Maturation:

   • Although the initial pellicle formation occurs quickly, further maturation can be observed over several hours. This maturation process involves the incorporation of additional salivary components and the establishment of a more complex structure.

Interaction with Bacteria

1. Bacterial Adhesion:

   • Bacteria that adhere to tooth surfaces do not contact the enamel directly; instead, they interact with the acquired enamel pellicle. This interaction is critical for the formation of dental biofilms (plaque).

2. Active Role of the Pellicle:

   • The acquired pellicle is not merely a passive adhesion matrix. Many proteins within the pellicle retain enzymatic activity when incorporated. Some of these enzymes include:
     • Peroxidases: Enzymes that can break down hydrogen peroxide and may have antimicrobial properties.
     • Lysozyme: An enzyme that can lyse bacterial cell walls, contributing to the antibacterial defense.
     • α-Amylase: An enzyme that breaks down starches and may influence the metabolism of adhering bacteria.

Clinical Significance

1. Role in Oral Health:

   • The acquired pellicle plays a protective role by providing a barrier against acids and bacteria, helping to maintain the integrity of tooth enamel and soft tissues.

2. Biofilm Formation:

   • Understanding the role of the pellicle in bacterial adhesion is essential for managing plaque-related diseases, such as dental caries and periodontal disease.

3. Preventive Strategies:

   • Dental professionals can use knowledge of the acquired pellicle to develop preventive strategies, such as promoting saliva flow and maintaining good oral hygiene practices to minimize plaque accumulation.

4. Therapeutic Applications:

   • The enzymatic activities of pellicle proteins can be targeted in the development of therapeutic agents aimed at enhancing oral health and preventing bacterial colonization.

Automated Probing Systems

Automated probing systems have become increasingly important in periodontal assessments, providing enhanced accuracy and efficiency in measuring pocket depths and clinical attachment levels. This lecture will focus on the Florida Probe System, the Foster-Miller Probe, and the Toronto Automated Probe, discussing their features, advantages, and limitations.

1. Florida Probe System

• Overview: The Florida Probe System is an automated probing system designed to facilitate accurate periodontal assessments. It consists of several components:

  • Probe Handpiece: The instrument used to measure pocket depths.
  • Digital Readout: Displays measurements in real-time.
  • Foot Switch: Allows for hands-free operation.
  • Computer Interface: Connects the probe to a computer for data management.

• Specifications:

  • Probe Diameter: The end of the probe is 0.4 mm in diameter, allowing for precise measurements in periodontal pockets.

• Advantages:

  • Constant Probing Force: The system applies a consistent force during probing, reducing variability in measurements.
  • Precise Electronic Measurement: Provides accurate and reproducible measurements of pocket depths.
  • Computer Storage of Data: Enables easy storage, retrieval, and analysis of patient data, facilitating better record-keeping and tracking of periodontal health over time.

• Disadvantages:

  • Lack of Tactile Sensitivity: The automated nature of the probe means that clinicians do not receive tactile feedback, which can be important for assessing tissue health.
  • Fixed Force Setting: The use of a fixed force setting throughout the mouth may not account for variations in tissue condition, potentially leading to inaccurate measurements or patient discomfort.

2. Foster-Miller Probe

• Overview: The Foster-Miller Probe is another automated probing system that offers unique features for periodontal assessment.

• Capabilities:

  • Pocket Depth Measurement: This probe can measure pocket depths effectively.
  • Detection of the Cemento-Enamel Junction (CEJ): It is capable of coupling pocket depth measurements with the detection of the CEJ, providing valuable information about clinical attachment levels.

3. Toronto Automated Probe

• Overview: The Toronto Automated Probe is designed to enhance the accuracy of probing in periodontal assessments.

• Specifications:

  • Probing Mechanism: The sulcus is probed with a 0.5 mm nickel titanium wire that is extended under air pressure, allowing for gentle probing.
  • Angular Control: The system controls angular discrepancies using a mercury tilt sensor, which limits angulation within ±30 degrees. This feature helps maintain consistent probing angles.

• Limitations:

  • Reproducible Positioning: The probe requires reproducible positioning of the patient’s head, which can be challenging in some clinical settings.
  • Limited Access: The design may not easily accommodate measurements of second or third molars, potentially limiting its use in comprehensive periodontal assessments.

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.