Assessing New Attachment in Periodontal Therapy

Assessing new attachment following periodontal therapy is crucial for evaluating treatment outcomes and understanding the healing process. However, various methods of assessment have limitations that must be considered. This lecture will discuss the reliability of different assessment methods for new attachment, including periodontal probing, radiographic analysis, and histologic methods.

1. Periodontal Probing

• Assessment Method: Periodontal probing is commonly used to measure probing depth and attachment levels before and after therapy.

• Limitations:

  • Coronal Positioning of Probe Tip: After therapy, when the inflammatory lesion is resolved, the probe tip may stop coronal to the apical termination of the epithelium. This can lead to misleading interpretations of attachment gain.
  • Infrabony Defects: Following treatment of infrabony defects, new bone may form so close to the tooth surface that the probe cannot penetrate. This can result in a false impression of improved attachment levels.
  • Interpretation of Results: A gain in probing attachment level does not necessarily indicate a true gain of connective tissue attachment. Instead, it may reflect improved health of the surrounding tissues, which increases resistance to probe penetration.

2. Radiographic Analysis and Reentry Operations

• Assessment Method: Radiographic analysis involves comparing radiographs taken before and after therapy to evaluate changes in bone levels. Reentry operations allow for direct inspection of the treated area.

• Limitations:

  • Bone Fill vs. New Attachment: While radiographs can provide evidence of new bone formation (bone fill), they do not document the formation of new root cementum or a new periodontal ligament. Therefore, radiographic evidence alone cannot confirm the establishment of new attachment.

3. Histologic Methods

• Assessment Method: Histologic analysis involves examining tissue samples under a microscope to assess the formation of new attachment, including new cementum and periodontal ligament.

• Advantages:

  • Validity: Histologic methods are considered the only valid approach to assess the formation of new attachment accurately.

• Limitations:

  • Pre-Therapy Assessment: Accurate assessment of the attachment level prior to therapy is essential for histologic analysis. If the initial attachment level cannot be determined with certainty, it may compromise the validity of the findings.

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.

Keratinized Gingiva and Attached Gingiva

The gingiva is an essential component of the periodontal tissues, providing support and protection for the teeth. Understanding the characteristics of keratinized gingiva, particularly attached gingiva, is crucial for assessing periodontal health.

Keratinized Gingiva

1. Definition:

   • Keratinized gingiva refers to the gingival tissue that is covered by a layer of keratinized epithelium, providing a protective barrier against mechanical and microbial insults.

2. Areas of Keratinized Gingiva:

   • Attached Gingiva:
     • Extends from the gingival groove to the mucogingival junction.
   • Marginal Gingiva:
     • The free gingival margin that surrounds the teeth.
   • Hard Palate:
     • The roof of the mouth, which is also covered by keratinized tissue.

Attached Gingiva

1. Location:

   • The attached gingiva is the portion of the gingiva that is firmly bound to the underlying alveolar bone.

2. Width of Attached Gingiva:

   • The width of attached gingiva varies based on location and can increase with age and in cases of supraerupted teeth.

3. Measurements:

   • Greatest Width:
     • Found in the incisor region:
       • Maxilla: 3.5 mm - 4.5 mm
       • Mandible: 3.3 mm - 3.9 mm
   • Narrowest Width:
     • Found in the posterior region:
       • Maxillary First Premolar: 1.9 mm
       • Mandibular First Premolar: 1.8 mm

Clinical Significance

• Importance of Attached Gingiva:

  • The width of attached gingiva is important for periodontal health, as it provides a buffer zone against mechanical forces and helps maintain the integrity of the periodontal attachment.
  • Insufficient attached gingiva may lead to increased susceptibility to periodontal disease and gingival recession.

• Assessment:

  • Regular assessment of the width of attached gingiva is essential during periodontal examinations to identify potential areas of concern and to plan appropriate treatment strategies.

Aggressive periodontitis (AP) is a multifactorial, severe, and rapidly progressive form of periodontitis that primarily affects younger patients. It is characterized by a unique set of clinical and microbiological features that distinguish it from other forms of periodontal disease.

Key Characteristics

• Rapid Progression: AP is marked by a swift deterioration of periodontal tissues.
• Age Group: Primarily affects adolescents and young adults, but can occur at any age.
• Multifactorial Etiology: Involves a combination of microbiological, immunological, genetic, and environmental factors.

Other Findings

• Presence of Aggregatibacter actinomycetemcomitans (A.a.) in diseased sites.
• Abnormal host responses, including impaired phagocytosis and chemotaxis.
• Hyperresponsive macrophages leading to exaggerated inflammatory responses.
• The disease may exhibit self-arresting tendencies in some cases.

Classification

Aggressive periodontitis can be classified into two main types:

1. Localized Aggressive Periodontitis (LAP): Typically affects the permanent molars and incisors, often with localized attachment loss.
2. Generalized Aggressive Periodontitis (GAP): Involves more widespread periodontal tissue destruction.

Risk Factors

Microbiological Factors

• Aggregatibacter actinomycetemcomitans: A primary pathogen associated with LAP, producing a potent leukotoxin that kills neutrophils.
• Different strains of A.a. produce varying levels of leukotoxin, with highly toxic strains more prevalent in affected individuals.

Immunological Factors

• Human Leukocyte Antigens (HLAs): HLA-A9 and B-15 are candidate markers for aggressive periodontitis.
• Defective neutrophil function leads to impaired chemotaxis and phagocytosis.
• Hyper-responsive macrophage phenotype, characterized by elevated levels of PGE2 and IL-1β, may contribute to connective tissue breakdown and bone loss.

Genetic Factors

• Familial clustering of neutrophil abnormalities suggests a genetic predisposition.
• Genetic control of antibody responses to A.a., with variations in the ability to produce protective IgG2 antibodies.

Environmental Factors

• Smoking is a significant risk factor, with smokers experiencing more severe periodontal destruction compared to non-smokers.

Treatment Approaches

General Considerations

• Treatment strategies depend on the type and extent of periodontal destruction.
• GAP typically has a poorer prognosis compared to LAP, as it is less likely to enter spontaneous remission.

Conventional Periodontal Therapy

• Patient Education: Informing patients about the disease and its implications.
• Oral Hygiene Instructions: Reinforcing proper oral hygiene practices.
• Scaling and Root Planing: Removal of plaque and calculus to control local factors.

Surgical Resection Therapy

• Aimed at reducing or eliminating pocket depth.
• Contraindicated in cases of severe horizontal bone loss due to the risk of increased tooth mobility.

Regenerative Therapy

• Potential for regeneration is promising in AP cases.
• Techniques include open flap surgical debridement, root surface conditioning with tetracycline, and the use of allogenic bone grafts.
• Recent advances involve the use of enamel matrix proteins to promote cementum regeneration and new attachment.

Antimicrobial Therapy

• Often required as adjunctive treatment to eliminate A.a. from periodontal tissues.
• Tetracycline: Administered in various regimens to concentrate in periodontal tissues and inhibit A.a. growth.
• Combination Therapy: Metronidazole combined with amoxicillin has shown efficacy alongside periodontal therapy.
• Doxycycline: Used at a dose of 100 mg/day.
• Chlorhexidine (CHX): Irrigation and home rinsing to control bacterial load.

Host Modulation

• Involves the use of sub-antimicrobial dose doxycycline (SDD) to prevent periodontal attachment loss by modulating the activity of matrix metalloproteinases (MMPs), particularly collagenase and gelatinase.

Dark Field Microscopy in Periodontal Microbiology

Dark field microscopy and phase contrast microscopy are valuable techniques in microbiological studies, particularly in the field of periodontal research. These methods allow for the direct observation of bacteria in plaque samples, providing insights into their morphology and motility. This lecture will discuss the principles of dark field microscopy, its applications in periodontal disease assessment, and its limitations.

Dark Field Microscopy

• Definition: Dark field microscopy is a technique that enhances the contrast of unstained, transparent specimens, allowing for the visualization of live microorganisms in their natural state.
• Principle: The method uses a special condenser that directs light at an angle, creating a dark background against which the specimen appears bright. This allows for the observation of motility and morphology without the need for staining.

Applications in Periodontal Microbiology

1. Alternative to Culture Methods:

   • Dark field microscopy has been suggested as a rapid alternative to traditional culture methods for assessing bacterial populations in periodontal plaque samples. It allows for immediate observation of bacteria without the time-consuming process of culturing.

2. Assessment of Morphology and Motility:

   • The technique enables direct and rapid assessment of the morphology (shape and structure) and motility (movement) of bacteria present in plaque samples. This information can be crucial for understanding the dynamics of periodontal disease.

3. Indication of Periodontal Disease Status:

   • Dark field microscopy has been used to indicate the status of periodontal disease and the effectiveness of maintenance programs. By observing the presence and activity of specific bacteria, clinicians can gain insights into the health of periodontal tissues.

Limitations of Dark Field Microscopy

1. Analysis of Major Periodontal Pathogens:

   • While dark field microscopy can visualize motile bacteria, it is important to note that many major periodontal pathogens, such as Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides forsythus, Eikenella corrodens, and Eubacterium species, are motile. However, the technique may not provide detailed information about their specific characteristics or pathogenic potential.

2. Differentiation of Treponema Species:

   • Dark field microscopy cannot differentiate between species of Treponema, which is a limitation when identifying specific pathogens associated with periodontal disease. This lack of specificity can hinder the ability to tailor treatment based on the exact microbial profile.

3. Limited Quantitative Analysis:

   • While dark field microscopy allows for qualitative observations, it may not provide quantitative data on bacterial populations, which can be important for assessing disease severity and treatment outcomes.

Ecological Succession of Biofilm in Dental Plaque

Overview of Biofilm Formation

Biofilm formation on tooth surfaces is a dynamic process characterized by ecological succession, where microbial communities evolve over time. This process transitions from an early aerobic environment dominated by gram-positive facultative species to a later stage characterized by a highly oxygen-deprived environment where gram-negative anaerobic microorganisms predominate.

Stages of Biofilm Development

1. Initial Colonization:

   • Environment: The initial phase occurs in an aerobic environment.
   • Primary Colonizers:
     • The first bacteria to colonize the pellicle-coated tooth surface are predominantly gram-positive facultative microorganisms.
     • Key Species:
       • Actinomyces viscosus
       • Streptococcus sanguis
   • Characteristics:
     • These bacteria can thrive in the presence of oxygen and play a crucial role in the establishment of the biofilm.

2. Secondary Colonization:

   • Environment: As the biofilm matures, the environment becomes increasingly anaerobic due to the metabolic activities of the initial colonizers.
   • Secondary Colonizers:
     • These microorganisms do not initially colonize clean tooth surfaces but adhere to the existing bacterial cells in the plaque mass.
     • Key Species:
       • Prevotella intermedia
       • Prevotella loescheii
       • Capnocytophaga spp.
       • Fusobacterium nucleatum
       • Porphyromonas gingivalis
   • Coaggregation:
     • Secondary colonizers adhere to primary colonizers through a process known as coaggregation, which involves specific interactions between bacterial cells.

3. Coaggregation Examples:

   • Coaggregation is a critical mechanism that facilitates the establishment of complex microbial communities within the biofilm.
   • Well-Known Examples:
     • Fusobacterium nucleatum with Streptococcus sanguis
     • Prevotella loescheii with Actinomyces viscosus
     • Capnocytophaga ochracea with Actinomyces viscosus

Implications of Ecological Succession

• Microbial Diversity: The transition from gram-positive to gram-negative organisms reflects an increase in microbial diversity and complexity within the biofilm.
• Pathogenic Potential: The accumulation of anaerobic gram-negative bacteria is associated with the development of periodontal diseases, as these organisms can produce virulence factors that contribute to tissue destruction and inflammation.
• Biofilm Stability: The interactions between different bacterial species through coaggregation enhance the stability and resilience of the biofilm, making it more challenging to remove through mechanical cleaning.

----------------------------------------------- 

Subgingival and Supragingival Calculus

Overview of Calculus Formation

Calculus, or tartar, is a hardened form of dental plaque that can form on both supragingival (above the gum line) and subgingival (below the gum line) surfaces. Understanding the differences between these two types of calculus is essential for effective periodontal disease management.

Subgingival Calculus

1. Color and Composition:

   • Appearance: Subgingival calculus is typically dark green or dark brown in color.
   • Causes of Color:
     • The dark color is likely due to the presence of matrix components that differ from those found in supragingival calculus.
     • It is influenced by iron heme pigments that are associated with the bleeding of inflamed gingiva, reflecting the inflammatory state of the periodontal tissues.

2. Formation Factors:

   • Matrix Components: The subgingival calculus matrix contains blood products, which contribute to its darker coloration.
   • Bacterial Environment: The subgingival environment is typically more anaerobic and harbors different bacterial species compared to supragingival calculus.

Supragingival Calculus

1. Formation Factors:

   • Dependence on Plaque and Saliva:
     • The degree of supragingival calculus formation is primarily influenced by the amount of bacterial plaque present and the secretion of salivary glands.
     • Increased plaque accumulation leads to greater calculus formation.

2. Inorganic Components:

   • Source: The inorganic components of supragingival calculus are mainly derived from saliva.
   • Composition: These components include minerals such as calcium and phosphate, which contribute to the calcification process of plaque.

Comparison of Inorganic Components

• Supragingival Calculus:

  • Inorganic components are primarily sourced from saliva, which contains minerals that facilitate the formation of calculus on the tooth surface.

• Subgingival Calculus:

  • In contrast, the inorganic components of subgingival calculus are derived mainly from crevicular fluid (serum transudate), which seeps into the gingival sulcus and contains various proteins and minerals from the bloodstream.