Oral Deposits

Oral Deposits

Lecture Overview

  • Discussed by: Jacey L. Mitchell, EdD, RDH

Introduction to Oral Biofilm

  • Definition of Biofilm: A biofilm is defined as a complex, highly organized, three-dimensional communal arrangement of microorganisms that adhere to a surface where moisture and nutrients are available (Darby & Walsh, 2015, p. 283).
  • Oral Biofilm Definition: A dense, transparent, non-mineralized mass of bacterial colonies in a gel-like matrix that adheres to one another, tooth surfaces, dental appliances, restorations, and oral mucosa (Darby & Walsh, 2015, p. 283).

Microorganisms in Oral Biofilm

  • Simplest Organisms: Involved in oral biofilm; thousands of species exist and can quickly replicate.
    • Over 600 species identified within oral biofilm.
  • Types of Bacteria:
    • Gram Positive: Characterized by a thick peptidoglycan cell wall.
    • Gram Negative: Possesses an outer membrane, thinner peptidoglycan layer, and greater variety of shapes.
  • Bacterial Shapes:
    • Bacilli: Rod-shaped bacteria (can be single or in chains).
    • Cocci: Spherical bacteria (includes diplococci in pairs, staphylococci in clusters, streptococci in chains).
    • Vibrio: Comma-shaped bacteria.

Biofilm Formation Process

Stages of Oral Biofilm Formation

  1. Pellicle Formation: Glycoproteins form an acquired pellicle immediately after teeth are cleaned. This pellicle acts defensively by protecting against demineralization.
  2. Colonization: Free-floating bacteria, such as Streptococcus mutans and Streptococcus sanguis, attach to the pellicle, initiating the development of biofilm.
  3. Bacterial Growth and Maturation: Initial colonizers (cocci) are replaced by filamentous forms and other mixed flora over Days 2-4.
  4. Dispersion: Mature biofilm may release cells to colonize new environments.

Attachment and Growth

  • Attachment Process: Underlying sugars facilitate the attachment of bacteria to enamel via the pellicle.
  • Growth of Biofilm: Once established, bacteria communicate and form a community, enhancing the survival of the biofilm.

Composition and Structure of Biofilm

  • Biofilm Composition:
    • Comprises approximately 80% water, with 20% solid matter (including organic and inorganic compounds).
    • Key components are microbial cells, extracellular polysaccharides (EPS), RNA, DNA, ions, lipids, and proteins.
  • Structure: Biofilms exhibit a heterogeneous structure with dense bacterial accumulation and channels for nutrient and waste transport.

Types of Plaque Biofilm

  • Supragingival Plaque Biofilm:
    • Exists above the gingival margin; associated with conditions such as marginal plaque and gingivitis.
  • Subgingival Plaque Biofilm:
    • Found below the gingival margin; associated with periodontal conditions like periodontitis.
  • Tissue-Associated Plaque Biofilm:
    • Loosely attached to pocket wall epithelium, allowing bacteria to invade gingival connective tissues, contributing to periodontal disease.
  • Unattached Bacteria: Free-floating, unorganized gram-negative rods and spirochetes found at the bottom of the sulcus.

Calculus Formation

  • Definition of Calculus: A calcified mass of bacterial plaque that is classified based on its location (supragingival or subgingival).
  • Formation Process:
    1. Pellicle formation begins.
    2. Biofilm matures and bacterial colonization occurs.
    3. Mineralization begins within 24-72 hours with foci of mineralization forming and uniting.
    4. Calcium and phosphate ions from saliva (supragingival) and gingival crevicular fluid (subgingival) contribute to calculus formation.
  • Timeline for Maturation: Initial soft deposits can begin transforming into calculus within 24-28 hours; complete maturation typically occurs within 10-20 days, averaging around 12 days.
  • Factors Affecting Calculus Formation::
    • The presence of deeper pockets leads to more organisms, increasing the risk of inflammation and subsequent mineralization due to enhanced sulcus fluid production.

Implications of Oral Biofilm and Calculus for Oral Health

  • Microbial Homeostasis: Refers to a balance of bacteria that supports oral health. Dysbiosis can lead to conditions like gingivitis and periodontitis.
  • Symbiosis and Dysbiosis:
    • Symbiosis: Relationship where commensal bacteria lead to health.
    • Dysbiosis: Imbalance within biofilm composition can result in disease.
  • Oral-Systemic Link: Emerging research indicating that oral health significantly affects overall health status.

Biofilm Management Strategies

  • Management Tools: Various methods mentioned for effective biofilm management and control in clinical practice.
  • Control Mechanism: Utilization of disclosing solutions to identify areas affected by biofilm for effective cleaning and patient education on oral hygiene practices.
  • Group Activity: An assignment to develop a script for patient education, focusing on biofilm formation, maturation, management, and its disease significance.

Conclusion

  • Encouragement of kindness and proactive engagement in patient care as fundamental values in practice. This includes the focus on educating patients regarding their oral health and the implications of biofilm.