Plaque related Dental Diseases

Question 1

Why do teeth specifically get plaque?

Answer 1

Normally, tissues are renewed constantly by shedding preventing accumulation of large masses of microorganisms. However, teeth provide a hard, non-shedding surface for development of extensive bacterial deposits.

There is an open junction between teeth and soft tissues

Fissures, grooves, and pits provide closed environments for bacterial growth

Question 2

How dense is dental plaque?

Answer 2

1 mm3 of dental plaque weighs approximately 1mg and has more than 100000000 bacteria.

In these deposites there are over 300 - 700 species.

Question 3

Does a specific type of bacteria cause periodontal disease/caries?

Answer 3

There are microorganisms communities resident in the mouth, the presence of which are beneficial and normal to the host.

A dynamic balance exists between the host and the resident microbiota in health

If this delicate relationship is broken down then disease (dysbiosis) occurs.

Question 4

What is the microorganisms community found on the tooth surface?

Answer 4

Dental plaque is the community of microorganisms found on a tooth surface as a biofilm embedded in a matrix of polymers of host and bacterial origin.

Question 5

How does dental plaque form?

Answer 5

Dental plaque forms via an ordered sequence of events

Dental plaque is structurally and functionally organised. It is a species rich microbial community.

Phase 1: Molecular adsorption to condition the biofilm formation

Phase 2: Bacterial adhesion by single organsims

Phase 3: Growth of extracellular matrix production and multiplication of adhering bacteria

Phase 4: Sequential adsorption of further bacteria to form a more complex and mature biofilm

Question 6

What kind of bacteria colonize the biofilm early?

Answer 6

Gram positive cocci

Question 7

What species are secondary colonizers of the biofilm?

Answer 7

Gram positive and negative rods

Question 8

What species are late colonizers of the biofilm?

Answer 8

Gram negative rods that are also anaerobic.

Question 9

What is the significance of microbial communities in biofilms?

Answer 9

Communication (Quorum sensing)

Trade (Nutrients, pH, redox, etc)

Costruction (Outer organisms protect)

Teamwork (Strength in numbers)

Question 10

What is material alba?

Answer 10

Soft accumulations of bacteria and tissue cells; lack organised structure of dental plaque; easily displaced by water spray.

Question 11

What is plaque made up of?

Answer 11

Microorganisms and intercellular matrix

Question 12

What microorganisms can cause plaque formation besides bacteria?

Answer 12

Mycoplasma

Yeast

Protozoa

Viruses

Question 13

What percentage of plaque mass is accounted for by intercellular matrix?

Answer 13

20 to 30%

Question 14

What is the source of supragingival plaque and subgingival plaque organic and inorganic components of intercellular matrix?

Answer 14

Supragingival plaque is saliva

Subgingival plaque GCF and blood

Calculus is frequently found in areas of the dentition adjacent to salivary glands

Question 15

What is the intercellular matrix composed of?

Answer 15

Calcium and phosphorus (Most)

Trace amounts: Sodium, potassium, and fluoride

Question 16

What are the organic components of intercellular matrix?

Answer 16

Polysaccharides produced by bacteria-dextran: Predominant form

Albumin: Originating from the crevicular fluid

Lipid material: Debris from the membranes of disrupted bacterial and host cells and possibly food debris

Question 17

Where does plaque generally accumulate?

Answer 17

Supragingival and hard surfaces: Teeth, implant, and restorations

Periodontal pocket

Buccal, palatal, and floor of the mouth epithelium

Dorsum of the tongue

Tonsils

Question 18

How can plaque be detected?

Answer 18

Visual

Periodontal probe or explorer

Disclosing agents

Question 19

What is the O’Leary Plaque index?

Answer 19

Method of recording presence of plaque on individual tooth surfaces

All teeth are disclosed using a disclosing solution

The operator (using an explorer or a tip of a probe) examines each stained surface for soft accumulations at the dentinogingival junction

Question 20

What is the gingival bleeding index?

Answer 20

Similar to the O’Leary index but you probe the gingival sulcus and record bleeding as present or absent. Bleeding % is calculated based on sites probed vs sites exhibited bleeding.