• Mineral Sources:
  • Supragingival: Saliva
  • Subgingival: GCF
• Crystal Composition:

  Crystal Type	Percentage
  Hydroxyapatite	58%
  Magnesium whitlockite	21%
  Octacalcium phosphate	12%
  Brushite	8%

• Color:
  • Supragingival: White/yellow
  • Subgingival: Dark brown/green-black
• Stains:
  • Green: Chromogenic bacteria
  • Yellow-brown: Chlorhexidine

Treatment Phases

1. Phase 1: Non – surgical
2. Phase 2: Surgical
3. Phase 3: Restorative
4. Phase 4: Maintenance Must progress through Phase 1 → 4 before Phase 2 or 3

Merin's Classification

• Class A: 6 months – 1 year recall
• Class B: 3 – 4 months recall
• Class C: 1 – 3 months recall

Epithelium Types

• Parakeratinized: Retains pyknotic nuclei in stratum corneum
• Orthokeratinized: No nuclei in stratum corneum
• Keratinization order: Palate > Gingiva > Tongue > Cheek (most to least)

Keratin Distribution

• K 1, 2, 10, 12: Orthokeratinized areas
• K 6, 16: Highly proliferative areas
• K 5, 14: Stratification specific
• K 19: Parakeratinized areas

Structural Components

• Stratum spinosum: Contains keratinosomes/Odland bodies (modified lysosomes)
• Basal lamina: 300 – 400 Å thick, joins epithelium to connective tissue
  • Lamina lucida (rich in laminin)
  • Lamina densa (rich in collagen type IV)
• Junctional epithelium: 0.25 – 1.35 mm long, formed by oral + reduced enamel epithelium

Clinical Probing

• Normal probing depth: 2 – 3 mm (requires apical penetration)
• Stippling: Orange peel appearance, restricted to attached gingiva
• Loss of stippling: Early sign of gingivitis

Morphological Classification

Three-Wall Defect (Intrabony Defect)

• Description: Defect contained by three bony walls
• Prognosis: Best regenerative potential
• Treatment: Ideal candidate for GTR procedures

Two-Wall Defect (Crater)

• Description: Defect between two adjacent teeth
• Characteristics: Interdental bone loss
• Prevalence: Most common osseous defect in chronic periodontitis

One-Wall Defect (Hemiseptum)

• Description: Defect with only one remaining bony wall
• Prognosis: Poorest regenerative potential
• Treatment: Often requires resective therapy

Bone Loss Patterns

Horizontal Bone Loss

• Associated Pocket Type: Suprabony pocket
• Pattern: Uniform reduction in alveolar bone height
• Radiographic Appearance: Horizontal radiolucency

Vertical/Angular Bone Loss

• Associated Pocket Type: Infrabony pocket
• Pattern: Uneven bone destruction
• Clinical Significance: More complex treatment requirements

• Plaque & Bacteria:
  • Plaque: Mainly extracellular polysaccharides.
  • Pellicle: Thin film post-cleaning.
  • Bacteria in 1g plaque: 2 × 10¹¹.
  • Early plaque: Gram-positive.
  • Saliva: Streptococci dominate.
  • First oral colonizer: S. sanguis.
  • Secondary colonizer: S. mutans.
  • Red Complex: Most associated with periodontal disease.
  • Green Complex: A. actinomycetemcomitans, E. corrodens, Capnocytophaga.
• Tests & Toxins:
  • BANA test: Detects P. gingivalis, T. denticola, B. forsythia.
  • Leukotoxin (116-kDa): Secreted by A. actinomycetemcomitans.
  • Myeloperoxidase: Prevents A. viscosus attachment.
• Immunoglobulins:
  • Saliva: IgA.
  • GCF: IgG.
• GCF Lymphocyte Ratio: T:B = 1:3.
• TLRs: Absent on bacterial cells.

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.