Cariology Exam One [Plaque Development Part 1 & 2: Banas]

Sterile

We used to teach that the womb is a ____ environment and that we begin to acquire a microflora the moment we are born

Placenta

New evidence supports that some bacteria may cross the ______

in the oral cavity (most similar to tongue and tonsil) of the mother

The microorganisms that cross the placenta appear to have originated

Latest thinking is that antigens of the microbiome, rather than viable organisms, cross over to train the immune system of the fetus

Latest think on microbiome and placenta

birth delivery

Most studies have found that bacterial diversity in the oral cavity is affected by mode of

vaginally compared to those delived by C-section

Greatest diversity of microbiome in infants that were delivered

- Environment

- Baby's put things in their mouth

- Salivary droplets (kisses etc)

- Food (not sterile)

- Caretakers, relatives

- Skin microflora

- Bacteria in milk

How do we get these bacteria (Other than birth)

The bacteria most likely to stay long term would be from the mouth of other people.

- Other mouth bacteria is already equipped for that way of live dawg

What bacteria is most likely to take resident in the babies mouth

vertical transmission of bacteria

Conventional wisdom is that the mother is the primary source of

Recovery of identical clonal types of cariogenic species (strep mutans) from mother and child more often than from the child and other family members

At the time of the study the mother was typically a stay at home mom. Meaning mothers were spending the most time with child.

- Pretty much when they tested mom and child they had similar bad bacteria (mutans)

Vertical transmission of bacteria primarily from the mother is based on

colonize

- Mouth bacteria is more likely to take up resident and push out the bacteria less equipped for the oral cavity.

Some bacteria species will transiently ______ but will eventually be replaced

colonize

- She just not equipped to live in the mouth homie

Some bacteria will never _____ and will be swallowed

The oral cavity will become home to those species that can utilize, and effectively compete for, the nutritional sources available, and withstand host defense mechanism

Why do only some species colonize

fissures of teeth

Adhesion is almost alway a prerequisite for colonization, though retentive site such as ___________ may obviate that need

enamel

Bacteria don't adhere directly to the

adhesins

Many bacteria have multiple specific ______ to promote efficient adhesion and/or adhesion to multiple receptors

Salivary proteins, glycoproteins, and other constituents

The enamel gets coated by _______ forming the pellicle

pellicle

Bacteria actually adhere to the ______ (not the tooth surface directly)

Electrostatic interactions (charged amino acids to a opposite charged surface)

Hydrophobic attractions

Hydrophilic attractions

Van der waals forces

Cationic bridging

Nonspecific weak-force mechanisms

adhesion

Nonspecific weak force interaction can initiate

Adhesins and receptor interaction

Weak force interactions can initiate stronger forces of

salivary pellicle, epithelial cells, matrix proteins (fibronectin or collagen), and platelets (important in endocarditis)

Oral bacteria will bind to

carbohydrates such as sialic acid, galactose, and fucose that are part of oligosaccharide chain on glycoproteins

The chemical composition of the receptors are often

other bacteria that have bound host receptors

In addition to binding host receptors, oral bacteria sometimes adhere to

coaggregation

Bacteria-to-bacteria adherence is called

- Fimbriae (also called pili or fibrils)

Bacterial adhesins

helically assembled proteins called fimbrillin or pilin.

Fimbriae are composed of

contains the particular adhesin

Often the tip of the fimbriae structure

Forces similar to those discussed for receptor ligand interactions

Adhesion by fimbriae is mediated by

proteins or lipoproteins that are anchored to the cell wall

- even some cell wall components have had adhesion properties attributed to them (teichoic acids)

Some adhesins are

Oral Streptococci

A lot of the primary plaque colonizers are

Is the quintessential bridging organism of early dental plaque to late dental plaque.

Fusobacterium nucleatum...

Heavily Gram +

Early dental plaque

Shifted to Gram -

Late dental plaque

the pellicle, or other host receptors on oral soft tissue

Some oral species are more proficient than others in adhering to the ____ or other _____

primary plaque colonizers or early colonizers

When referring to teeth, the species which are more proficient than others at adhering to the pellicle and other host receptors on oral soft tissue are called

more efficient at adhering to the early colonizers

Secondary or late colonizers

Fluorescent in situ hybridization

Various groups have found they can do "FISH". Whats this stand for

Fluorescent labels that admit ad different wavelengths. Can construct a map of plaque organism development

FISH allows for

more anaerobic the plaque gets

The older the plaque gets the

- Early on you can see that strep and Gemella are found in all children

- As you go on the number of genera in every child increases dramatically

- Gemella and Step are the ones that you have a good exposure to and establish well

- Later you find a vast diversity

- Prevotella is significant

- Mainly facultative or aerobic species

- After eruption get more anaerobic species

Interpret the graph

Don't have a lot of anaerobic species until the teeth erupt (except in this case)

- She an outlier

Why is Prevotella significant in the previous graph

Streptococcus, Veillonella, Gimella

Species of the genera ____,____,___ were found in 100% of infants at three months

Prevotella

_____ was a highly represented anaerobic genus at 3 months but in general the diversity of anaerobes increases with age, likely as teeth erupt creating subgingival niche

diversity

Species ____ increases with age

lactobacilli

- He did not mention lactobacilli but its on the slide

- We know this from micro though because we are geniuses

The microbiome composition at 3 months did not with future caries, with the exception of

Interpret this graph

- This figure is for Illustrative purpose only - Dr. Banas

- We see at 18 month more stability of the distribution of the different types of organisms

END OF PART ONE

END OF PART ONE

START OF PART TWO

START OF PART TWO

18

Generally around ____ months you start to see a more stable biofilm

biofilm

A ____ is a collection of bacterial microcolonies on a surface

Polysaccharide matrix, and are metabolically heterogeneous

The bacteria within the microcolonies of a biofilm are structured within a _____ and are ________

antimicrobials, quorum sensing

The bacteria within the microcolonies of a biofilm have increased resistance to ______ and often elaborate a chemical or peptide signals in a process called ___

diffuse

Antibiotics don't _____ very well through the matrix of a biofilm

- Streptococcus (coccus)

- Granulicatella (coccobacillus)

- Gemella (coccobacillus)

- Rothia (coccobacillus)

- Actinomyces (Filamentous rod)

- Corynebacterium (rod)

- Abiotrophia (coccus)

Recognize these common names of genera found commonly in dental plaque [Gram +]

- Veillonella (coccus)

- Neissseria (coccus)

- Haemophilus (coccobacillus)

- Bergeyella (rod)

- Aggregatibacter (rod)

- Capnocytophaga (rod)

- Fusobacterium (anaerobic rod)

- Porphyromonas (anaerobic rod)

- Prevotella (anaerobic rod)

- Alloprevotella (anaerobic rod)

- Leptotrichia (anaerobic rod)

Recognize these common names of genera found commonly in dental plaque [Gram -]

Hemolysis

_____ on blood agar was used to identify Beta-hemolytic strep

alpha-hemolytic strep, nonpathogenic commensal

The _______ or viridans streptococci, were collectively though of as ______ species

Lyse

Beta hemolytic is the ability of organisms to ____ red blood cells

turned the agar (gel shit) a greenish color

Alpha hemolytic means

Fancy for nothing is happening (does nothing)

Gamma hemelytic

This is true

- This is just an adjective describing alpha hemolytic species

There is no specific species named Streptococcus Viridans

4

- We are not born with a genetically determined microbiome however genetics do influence the composition

QUESTION: Each of the following statements is true except?

1. Adhesins and receptors may sometimes be of the same molecular composition, for example both may be proteins

2. Some bacterial species, such as Gram-negative obligate anaerobes, become more abundant as an infant ages

3. The colonization of the tooth surface is aided by bacteria adhering to one another in a process known as coaggregation

4. we are born with a genetically determined oral microbiome; as the infant grows the only change is in an increase in total number of bacteria

5. Saliva coats teeth, forming a pellicle to which bacteria adhere

Ya this is true

Host receptors differ from one site to another in the oral cavity

Erupt

Certain bacterial species in the oral cavity are only acquire once the teeth

niches, or microenvironments, that are shaped by host anatomy and physiology

Overall, the oral cavity is comprised of several distinct

- Gingival crevice (subgingival plaque)

- Coronal plaque (supragingival plaque)

- Tongue

- Buccal mucosa

- The saliva will mostly contain representatives from each of these niches

In the oral cavity we generally consider distinct niches to be

NO, there are distinct differences but there are also distinct commonalities

Is your oral microbiome the same as your neighbor

Lesser Diversity

- Similar sites; same tooth

- Same tooth; Buccal vs Lingual, Mandibular vs Maxillary

- Similar sites; Different teeth

- Same tooth; Supragingival vs subgingival

- Similar teeth, similar sites; different individuals

Big take away is that different niche's have greater diversity as well as from person to person

Location: Rank microorganisms in terms of Lesser diversity ---> Greater diversity

State of knowledge and culturing techniques sometimes made it difficult to compare studies. Many distinct species were at one time classified as a single species

Pre-1960s: In vitro culture of oral samples:

Greater precision in taxonomy. Begin to realize the extent to which a substantial portion of the oral microbiota cannot be cultivated

1980s: Dawn of the age of molecular Biology/Genetics:

Examine the oral microbiota in health and disease. these are largely based on DNA hybridization or sequencing

2000's: New non-culture based taxonomic studies:

800

Some believe that the number of species is considerably higher

Non-cultured based studies have determined that there are in excess of ___ species in the oral cavity

30-70, 20-30

Any given individual will have about __-____ predominant species in the oral cavity, or about __-___ per site

the microbiome will almost certainly be more similar from site to site (within a niche) in a given individual than between identical sites in two different individuals

Some species and relative proportions will be similar from individual to individual BUT

sites of most common dental pathologies- caries and periodontal disease

Of all the niches in the oral cavity the greatest focus is on supra and sub- gingival plaque. That is because these are the sites of the most ___________

- Microbiota of the tongue may be associated with halitosis (bad breath)

- Saliva and plaque organisms are probably the source of endodontic infections

- Any site in the oral cavity, but most likely dental plaque, can be a source of systemic infection such as endocarditis

Other oral microbiome disease association

- Heavily Gram +

- Predominance of cocci

- Mostly facultative anaerobes

Early plaque

- Increasing representation of Gram -

- Many morphological types

- Facultative anaerobes and obligate anaerobes

Mature plaque

- Mix of Gram + and -

- Mix of cocci and rods

- Mix of facultative and anaerobes

- More carbohydrate fermenters

- Firmly adherent

Supragingival plaque

- Higher proportion of Gram -

- More Gram - rods and spirochetes

- More obligate anaerobes

- More proteolytic species

- less adherent, more motile (less host defenses)

Subgingival plaque

beneficial and antagonistic

While the physical properties of the environment will shape microbial ecology, so will __________ and _______ interactions between bacterial species

- Enzyme complementation

- Coaggregation

- Inactivation of inhibitors

- Subversion of host defenses

Beneficial (Cooperation) interactions within Plaque

- Bacteriocins

- Organic acids

- Low pH

- Nutrient competition

Antagonistic (competitive) interaction within Plaque

Food webs

Beneficial and antagonist interactions means the plaque can be described in terms of

good microbiome than it is to correct a bad dysbiosis

It is a lot easier to maintain a _____

It can't be changed

Once your microbiome is stabilized after 18 months doesn't mean

dietary

______ choices and smoking can bring about substantial changes

This is a fact

There are also changes that accompany maturation

environment has a influence on the microbiome

Twin studies show increasing divergence with age, indicating that

3

QUESTION: Each of the following statement is TRUE except

1. Dental plaque is considered a biofilm with a composition that is strongly influenced by ordered colonization, host differences, and behavioral choices such as diet

2. Hundreds of bacterial species may be found in the oral cavity but the number of predominant species in any given individual is in the range of 30-70

3. The composition of supragingival plaque is predominantly Gram - whereas subgingival plaque is predominantly Gram +

4. Generalities regarding the composition of the microflora within different oral niches can be made even though individual differences can be significant

reproduce

The goal of bacteria, like any biological entity, is to

Give and take

Bacterial interaction with the host is an evolution-driven ______

normal microbiota stays under control

The bacteria evolve to take advantage of an environment, which in this case is in the host. The host evolves, to ensure that its

- Flow of saliva; swallowing

- Slough off cells

- Chewing

- Movement of the tongue

Physical host plaque control

adhesion

Bacteria use ____ mechanisms to counter mechanical removal

This is true

All microbes need iron

Clumps up bacteria and makes it difficult for them to adhere

Agglutinin

- Saliva harbors anti-microbial factors

- Lysozyme

- Histatins (histidine-rich proteins)

- Peroxidase and thyiocyanate

- Lactoferrin

- Salivary mucins and parotid agglutinnin

- Several other salivary factors

Biochemical or enzymatic host plaque control

- Break bond in peptidoglycan

- Kill via amphipathic sequences

- Induce bacteria to kill themselves

- Agglutinate bacteria

Lysozyme