Student RDH micro+immunology part 2

Approx. 2 weeks

However long after plaque accumulation does gingivitis become visible?

4 days

Gram-negative bacteria starts to appear in dental biofilm about how many days after plaque accumulation?

Not harmful

What does innocuous mean?

Pathogenic (virulent)

———————— bacteria are capable of causing disease. Gram-negative, motile, anaerobic bacteria are more harmful than gram-positive, non-motile, and aerobic bacteria in the oral cavity.

Gram positive bacteria

This type of bacteria is stained with purple crystal violet dye. ( has a thicker peptidoglycan wall that retains the stain). They have thick, single-cell walls and are capable of releasing exotoxin.

Gram-negative bacteria

This type of bacteria stains red, not purple with crystal violet. (They have thinner peptidoglycan calls). Have double-cell walls. Capable of releasing endotoxin and exotoxin, which are harmful substances.

Endotoxin

Toxin that is bound to the bacterial cell wall and released when the bacteria rupture (lysis). Highly heat stable (can withstand 100°C for an hour).

Exotoxin

Toxin bound to protein of the bacteria and releases by filtration of bacterial cultures. Less heat stable (destroyed mostly at 60°C).

Gram-positive

Bacteria that has a 1. Plasma membrane and 2. Cell wall

Gram-negative

Bacteria that has a 1. Plasma membrane, 2. Cell wall, and 3. Another plasma membrane.

Aerobic bacteria

Bacteria that requires oxygen to survive. Less harmful.

Anaerobic bacteria

Bacteria that cannot survive in the presence of oxygen.

Anaerobic

Subgingival biofilm includes more of this type and motile bacteria compared to supragingival calculus.

Facultative anaerobic bacteria

Bacteria that can survive with or without oxygen.

Diplo

This prefix means pairs. Ex. —————cocci, —————bacilli.

Strepto

This prefix means a chain of. Ex. —————-cocci, —————-bacilli.

Genus

The name that is capitalized and italicized referees to a specific ————— of bacteria.

Spirillum

Bacterium that has a spiral shape

Spirochetes

Very thin, elongated, flexible spiral bacteria that are motile via endoflagella (appendage protruding from the cell body).

Bacillus

A bacterium that has a rod shape.

Primary factors

Dental biofilm and bacteria are the ——————— factors in the initiation and progression of caries and periodontal disease. Bacteria are transmissible, therefore, caries and periodontal diseases are transmissible.

Cavitation

The process of a cavity formation

Carious lesions

These can be cavitated (with a hole) or non-cavitated (without a hole). A non-cavitated ————— ————— can be different colour and is usually whiter.

Demineralization

Minerals (calcium and phosphorus) are removed from the tooth structure by acid

Secondary caries (recurrent)

Caries underneath an existing restoration.

Arrested caries

Areas where demineralization has stopped. Usually darker in colour than the original structure.

White leasions

Subsurface demineralization under the outer layer of the tooth. Smooth in texture. Do not use ultrasonic or sharp instruments on these areas.

Fermentable carbohydrate, bacteria, and tooth structure

These are the 3 components needed for the formation of caries:

Monosaccharides and disaccharides

Nearly all carbohydrates can be broken down and metabolized by organisms. These 2 type of sugars are the most cariogenic. Bacteria synthesize sucrose and other fermentable carbohydrates and produce acids.

Streptococcus mutans

This bacteria is the main species involved in the caries process. Another contributing species is Streptococcus sobrinus.

Gram positive

Lactobacillus: gram what? Rod shaped.

Bifidobacteria

This is a bacteria that is associated with childhood caries. Often found in breast fed babies.

Mutans streptococci and Bifidobacteria

These 2 bacteria are most active in the initial stage of caries formation.

Lactobaccili

This bacteria is more active during the progression of the cavity.

Critical pH

This is the pH at which hydroxyapatites in dental structure start to dissolve.

6.7-7

Normal pH of the mouth is around

5.5

Critical pH for enamel demineralization is on average:

6.2-6.7

Critical pH for root demineralization is around:

Roots demineralize easier than enamel.

9

Toothpaste is considered to have a pH of around —

Frequency

This determines how often bacterial plaque feeds on carbohydrates.