Perio - Video 4

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Questions and Answers

What is the primary source of inorganic constituents in supragingival dental plaque?

Saliva (correct)

Gingival crevicular fluid

Food particles

Blood plasma

What is the function of glycoproteins and proline-rich proteins in the pellicle?

To destroy bacteria

To harden the tooth surface

To serve as attachment sites for bacteria (correct)

To provide nutrients to bacteria

What is the difference between adhesion and attachment of bacteria in dental plaque formation?

Adhesion occurs in hours, while attachment occurs in days

Adhesion is weak and reversible, while attachment is strong and irreversible (correct)

Adhesion occurs in minutes, while attachment occurs in hours

Adhesion is strong and irreversible, while attachment is weak and reversible

What is the purpose of co-adhesion in dental plaque formation?

To allow firmly attached primary colonizers to provide new receptors for attachment of other bacteria Signup and view all the answers

What is the trend observed in the shift from facultative gram-positive to anaerobic gram-negative bacteria during dental plaque maturation?

From facultative gram-positive to anaerobic gram-negative Signup and view all the answers

What is the primary source of organic constituents in dental plaque?

Saliva Signup and view all the answers

How long does it take for colonization and plaque maturation to occur?

Within 24 to 48 hours Signup and view all the answers

What is the function of the pellicle in dental plaque formation?

To provide attachment sites for bacteria Signup and view all the answers

What type of forces are involved in the initial adhesion of bacteria to the pellicle?

Weak reversible Vander Waals and electrostatic forces Signup and view all the answers

What is the primary source of inorganic constituents in subgingival dental plaque?

Gingival crevicular fluid Signup and view all the answers

What type of plaque is located above the gingival margin?

Super gingival plaque Signup and view all the answers

What type of bacteria are generally found in super gingival plaque?

Aerobic bacteria Signup and view all the answers

What is the trend observed in the layers of plaque as it grows out from the tooth surface?

Gram positive to gram negative Signup and view all the answers

What is unique about the sub gingival plaque compared to super gingival plaque?

Gram negative bacteria tend to accumulate both in the early and later layers Signup and view all the answers

What is the difference between super gingival and sub gingival plaque?

Super gingival plaque is located above the gingival margin and sub gingival plaque is below Signup and view all the answers

What type of bacteria thrive in the sub gingival region?

Anaerobic bacteria Signup and view all the answers

What is the direction of plaque growth from the tooth surface?

From left to right Signup and view all the answers

What is the characteristic of the early layers of plaque that are directly attached to the tooth?

Gram positive Signup and view all the answers

What primarily consists of glycoproteins, purine-rich proteins, and inorganic molecules?

Pellicle Signup and view all the answers

What type of bacteria are the primary early colonizers?

Streptococcus Signup and view all the answers

What do secondary late colonizers tend to feed on?

Amino acids Signup and view all the answers

What is the function of Fusobacterium?

Bridge between primary and secondary colonizers Signup and view all the answers

What is the term for the communication among bacteria in the biofilm?

Quorum sensing Signup and view all the answers

What is the benefit of quorum sensing in the biofilm?

Encourage the growth of beneficial species and discourage the growth of competing species Signup and view all the answers

What is the characteristic of biofilm bacteria that makes them more resistant to antimicrobial agents?

Their ability to form a giant wall Signup and view all the answers

What is the term for the fluid channels that run through the plaque mass?

Fluid channels Signup and view all the answers

What is the term for the group of living microorganisms that includes the pellicle, primary colonizers, and secondary colonizers?

Biofaon Signup and view all the answers

What is the characteristic of planktonic bacteria compared to biofilm bacteria?

They are less resistant to antimicrobial agents Signup and view all the answers

What is the arrangement of microbe complexes in the image similar to?

The actual arrangement of bacterial species in the plaque Signup and view all the answers

Which complexes are considered high priority for the board exam?

Red complex and its three bacteria Signup and view all the answers

What is the red complex associated with?

Bleeding on probing and deep pocket depths Signup and view all the answers

What is the purpose of the orange complex?

To support the sequential nature of plaque maturation Signup and view all the answers

What is the name of the bacteria that causes gingivitis?

P Gingivalis Signup and view all the answers

What is the ecological plaque hypothesis?

A theory that the mouth is an ecosystem, and bacteria and host factors influence the environment Signup and view all the answers

What is the significance of the tooth surface in the image?

It is located on the left side of the image Signup and view all the answers

Which of the following bacteria is NOT part of the red complex?

Fusobacterium nucleatum Signup and view all the answers

What is the purpose of remembering the 'peas' and 'T's' in the red complex bacteria?

To remember the names of the bacteria in the red complex Signup and view all the answers

What is the correct order of the plaque hypotheses?

Nonspecific, specific, ecological Signup and view all the answers

Which bacterium causes aggressive periodontitis?

A. actinomycetemcomitans Signup and view all the answers

Which bacterium is associated with healthy gingiva but can also cause root caries?

Actinomyces Signup and view all the answers

Which of the following bacteria is a bridge microorganism?

F. nucleatum Signup and view all the answers

Which bacterium is known to cause chronic periodontitis?

P. gingivalis Signup and view all the answers

Which bacterium is associated with pregnancy gingivitis?

P. intermedia Signup and view all the answers

Which bacterium is most commonly known to cause acute necrotizing form of either gingivitis or periodontitis?

T. denticola Signup and view all the answers

Which bacterium is notorious for causing coronal caries?

S. mutans Signup and view all the answers

Which bacterium is one of the most common oral bacteria and resides mostly on the tongue?

S. salivarius Signup and view all the answers

Study Notes

Plaque Composition

Two main types of plaque regions: Supragingival (above the gingival margin) and Subgingival (below the gingival margin)
Supragingival plaque:
- Bacteria are generally aerobic
- Early layers of plaque tend to be Gram-positive
- Outer layers tend to be Gram-negative
Subgingival plaque:
- Bacteria are generally anaerobic
- Gram-negative bacteria tend to accumulate in both early and later layers
- Gram-positive bacteria are present in early layers, but decrease in later layers

Plaque Formation

Initial step: Formation of pellicle within seconds of tooth cleaning
- Consists of glycoproteins, proline-rich proteins, and other molecules that serve as attachment sites for bacteria
- Not harmful by itself, but provides attachment sites for bacteria
Second step: Adhesion and attachment of bacteria within minutes
- Initial adhesion is weak and reversible, due to Vander Waals and electrostatic forces
- Firm attachment is strong and irreversible, due to specific bacterial adhesion molecules and receptors provided by pellicle
Third step: Colonization and plaque maturation within 24-48 hours
- Firmly attached primary colonizers provide new receptors for attachment of other bacteria
- Shift from Gram-positive to Gram-negative bacteria as plaque grows and matures

Plaque Maturity

Mature plaque is a biofilm, consisting of fluid channels that permit passage of nutrients and waste products
Quorum sensing: communication among bacteria in biofilm to encourage growth of beneficial species and discourage growth of competing species
Biofilm bacteria are more resistant to antimicrobials than planktonic bacteria

Microbial Complexes

Different colors and names are associated with different microbial complexes (e.g. blue complex, yellow complex, orange complex, red complex)
Red complex bacteria (P. gingivalis, T. denticola, and T. forsythia) are associated with periodontal disease and are important to know for the board exam
Orange complex bacteria (F. nucleatum, P. intermedia, and S. rectus) precede the presence of red complex bacteria and support the sequential nature of plaque maturation

Major Bacteria to Know

Aggregatibacter actinomycetemcomitans (Aa): causes aggressive periodontitis
P. gingivalis: causes chronic periodontitis
T. denticola: causes acute necrotizing gingivitis or periodontitis
T. forsythia: associated with periodontal disease
P. intermedia: influences pregnancy gingivitis
F. nucleatum: orange complex bacteria, bridge microorganism
Actinomyces: associated with healthy gingiva, can cause root caries
S. mutans: notorious for causing coronal caries
S. salivarius: one of the most common oral bacteria, resides mostly on the tongue

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Description

Learn about the composition of dental plaque, including the two main types of plaque regions, supragingival and subgingival, and the characteristics of bacteria in each region.