Aetiology of perio diseases part 1 Flashcards
What is dental biofilm?
A complex microbial community (predominantly bacteria) found at on tooth and oral surfaces in a matrix of bacterial and salivary origin, firmly adherent to the tooth surface.
How does dental biofilm contribute to periodontal disease?
Biofilm allows pathogenic bacteria to interact within a matrix-enclosed environment, leading to inflammationof gingival and periodontal tissues.
What are the two types of periodontal disease?
Gingivitis (inflammation of the gingiva) and periodontitis (inflammation of supporting tissues leading to bone and ligament loss).
What is the role of saliva in dental plaque?
Saliva contains proteins and peptides with antimicrobial activity and forms a pellicle that influences bacterial attachment.
What are the two main types of dental plaque?
Supragingival and subgingival plaque.
What is the composition of dental plaque?
Cells (bacteria, epithelial cells, leukocytes), extracellular matrix (proteins, polysaccharides, lipids), and inorganic components (calcium, phosphorus).
How does calculus form?
By mineralization of dental plaque, primarily with calcium and phosphorus from saliva.
What is the acquired pellicle?
A conditioning film formed from salivary proteins and glycoproteins on the tooth surface, which aids bacterial attachment.
Which bacteria are primary colonizers of dental plaque?
Gram-positive bacteria such as Streptococcus sanguis and Actinomyces viscosus.
What is co-aggregation in biofilm formation?
The process by which genetically identical bacteria adhere to one another, promoting further bacterial attachment.
What is the function of the intermicrobial matrix in plaque?
It retains bacterial products for interactions and provides an environment for nutrient exchange and waste removal.
What role does dextran play in dental plaque?
Dextran, a polysaccharide, acts as a sticky adhesive material aiding bacterial colonization.
What is the significance of F. nucleatum in biofilm?
It is an important bridging microorganism that connects primary and secondary colonizers in the biofilm.
How do secondary colonizers attach in plaque?
They adhere to primary colonizers or the extracellular matrix of the biofilm, enhancing its pathogenicity.
Why is subgingival plaque more resistant to removal?
It resides in a protected location, not subjected to intraoral abrasion or salivary defense components.
What bacterial species dominate supragingival plaque?
Gram-positive cocci (e.g., Streptococcus) and rods (e.g., Actinomyces species).
What are the main bacteria in tissue-associated subgingival plaque?
Porphyromonas gingivalis, Prevotella intermedia, Aggregatibacter actinomycetemcomitans.
What are the key inorganic components of dental plaque?
Calcium and phosphorus, primarily from saliva.
What is the significance of dental plaque in periodontal disease?
Plaque biofilm’s structure protects bacteria from host defenses and antimicrobial agents, allowing long-term survival and disease progression.
How does bacterial colonization change plaque over time?
Plaque matures from primarily aerobic to anaerobic with secondary and tertiary colonizers increasing its pathogenicity.
How do early colonizers affect the biofilm environment?
Early colonizers like streptococci utilize oxygen, creating a low-oxygen environment that favors anaerobic bacterial growth.
What is the role of lactate and formate in bacterial interactions?
These byproducts from streptococci and actinomyces are used by other bacteria like Veillonella for metabolism.
How does Porphyromonas gingivalis benefit from other bacteria?
It uses metabolic products like succinate, produced by organisms like Capnocytophaga, to enhance its growth.
What is the specific plaque hypothesis?
It suggests that periodontal disease results from the presence or increase of specific pathogenic microorganisms in dental plaque.
What is the nonspecific plaque hypothesis?
It proposes that periodontal disease results from the accumulation of plaque and the collective effect of its microbial products.
What are the main antimicrobial agents in saliva?
IgA, lactoferrin, lysozyme, and peroxidases.
What is a biofilm?
A structured community of microorganisms enclosed in a self-produced matrix that adheres to surfaces.
How does smoking affect plaque formation?
Smoking promotes plaque accumulation by reducing salivary flow and impairing immune response.
What is the role of mechanical cleaning in plaque control?
It disrupts the biofilm structure, reducing bacterial colonization and preventing plaque maturation.
What happens during plaque maturation?
Bacteria multiply, forming a thick biofilm with reduced oxygen levels, favoring the growth of anaerobic pathogens.
What is the ecological plaque hypothesis?
It suggests that periodontal disease results from shifts in the balance of microbial species in the biofilm, influenced by environmental changes.
How does the acquired pellicle protect the tooth surface?
It forms a barrier that influences bacterial attachment and can reduce enamel colonization by exogenous microorganisms.
What is the significance of Campylobacter rectus in plaque biofilm?
It is a secondary colonizer that contributes to the pathogenicity of plaque and periodontal disease.
How does plaque biofilm resist antibacterial agents?
The biofilm structure retains bacterial products and shields bacteria from external agents.
What factors influence plaque formation?
Mechanical cleaning, smoking, diet, physical space, and the host’s innate defense system.
