Week 2

Question 1

Global burden of Caries

• _________ people worldwide are affected by oral disease
• Nearly _____ of the global population
• Dental caries of the permanent teeth is the most _______ of all health conditions assessed
  
  • Incidence and prevalence persists in younger children _____ years of age since 1990

Answer 1

3.58 billion

half

prevalent

<10

Question 2

Average saliva production in Adults and Kids

Answer 2

Child: 0.5-2L

Adult: 0.5-1.5L

Question 3

Antimicrobial components of saliva (5)

Answer 3

lysozyme

lactoferrin

histatins

peroxidase

secretory IgA

Question 4

lysozyme function to inhibit bacteria

Answer 4

Lysozyme digests the cell walls of Gram-positive bacteria by breaking the β(1-4) bond between N-acetylmuramic acid and N-acetylglucosamine (NAM-NAG) in peptidoglycan

Question 5

lactoferrin funcction to inhibit bacteria

Answer 5

Lactoferrin inhibits bacterial growth by binding and sequestering Fe2+ ions, and in the apo (iron free) state can be toxic to bacteria and interfere with bacterial adhesion

Question 6

histatins function to inhibit bacteria

Answer 6

cationic histidine rich proteins that kill Candida albicans and some bacteria.

can bind and infiltrate yeast which results in arrest of the cell cycle and the cells lose ATP by efflux

Question 7

peroxidase function to inhibit bacteria

Answer 7

catalyzes the oxidation of thiocyanate (SCN−) to hypothiocyanite (OSCN−) by hydrogen peroxide.

Hypothiocyanite oxidizes SH groups in bacterial enzymes and inhibits bacterial metabolism.

Question 8

secretory IgA function to inhibit bacteria

Answer 8

agglutination

Question 9

2 major salivary agglutinins

Answer 9

Secretory IgA

Salivary Mucins

Question 10

characteristics of secretory IgA

Answer 10

dimeric IgA

joining J chain

secretory component (facilitates trans-cellular transportation)

Question 11

characteristics of salivary mucins

Answer 11

polypeptide backbone

serine, threonine, proline rich domains

oligosaccharide chains (glucose, galactose, fructose, mannose) w

Question 12

what is agglutination?

Answer 12

the clumping of particles (antigens/antibody, mucin/surface protein)

Agglutinins are a major component of saliva and play an important role in mucosal immunity

Majority of agglutinated cells are swallowed and cleared from the oral cavity

Immobilized S-IgA/ mucins embedded in the acquired pellicle result in “fixed” agglutination on the tooth surface

Question 13

difference between the salivary pellicle and aquired pellicle

Answer 13

when the salivary pellicle coats a hard surface (teeth), it is the aquired pellicle

Question 14

what are the 3 virulence factors of Strep Mutans

Answer 14

Adhesion

Acidogenicity (makes acid)

Aciduricity (can survive in an acidic environment)

Question 15

Major components of Adhesion:

________transferase (GTF)/ ________transferase (FTF)

1. Convert ______ into _____ and _____ respectivel
2. Facilitate _______ of Sm and other bacteria (Co-adhesion)
3. Forms an _______________ that serves as energy storage
4. _______ binding proteins (GBP)

Answer 15

Glucosyl, Fructosyl

sucrose, glucans, fructans

adhesion

external polysaccharide (EPS) matrix

glucan

Question 16

Major components of acidogenicity (making acid)

S mutans uses ________ fermentation

1. Converts _______ or _______ into ______ via glycolysis
2. _________ can be shuttled in to various metabolic pathways in which organic acids are generated and ______ is produced for the cell

Answer 16

glycolytic

glucose, sucrose, pyruvate

pyruvate

ATP

Question 17

Major components of S mutans Aciduricity (can survive in acidic environment)

1. how does it survive with external ph?
2. how does it survive with internal pH?

Answer 17

external pH: modifies membrane composition which will decrease proton permeability

internal pH:

a. pump out the protons
b. F1F0 ATPase –> costs energy!

Question 18

Know the critical pH for Hydroxyapatite and Fluorapatite and the role of each in enamel equilibrium in the presence of acids and saliva

Answer 18

Hydroxyapetite is the building block for enamel (critical pH = 5.5)

Fluorapetite protects tooth from demineralization (critical pH = 4.5)

The ”Critical pH” for enamel remineralization/ demineralization is pH 5.5

Question 19

major target of fluoride

Answer 19

inhibits glycolysis

inhibits ATR mechanisms

a. arginine deiminase system (ADS)
b. ammonia synthesis

c. F0F1 ATPase (makes it non functional –> protons enter cell and destroy it)

Question 20

Silver can

• disrupt __________ cell walls
• _____ cell membranes
• denature _______
• bind ______

what is the zombie effect?

Answer 20

peptidoglycan

lyse

ribosomes

DNA

• Bacteria that are killed by SDF further act as a carrier for silver ions
• This can kill other living bacteria nearby in a process known as the “zombie effect.”

Question 21

Target of Xylitol and mechanism in Streptococcus mutans

Answer 21

xylitol directly inhibits DexA(enzyme that breaks down dextran, which is a class of branched glucans, plays a role in normal activity of glucosyltraansferases and glycosyltransferase efficieny)

inhbition of DexA c–> poor biofilm formation by S mutans

Reduced acid production

Question 22

Target of Epigallocatechin gallate (EGCG) and mechanism in Streptococcus mutans

Answer 22

• Competes for binding on the salivary pellicle
• Inhibit normal function of glucosyltransferases (gtf B,C,D)
• Alter bacterial cell walls and/or cell membrane

Question 23

What are the four modes of transmission highlighted in the lecture recording? Provide an example of each

Answer 23

1. Direct contact (blood or body fluids)
2. Indirect contact (contaminated instrument or surface)
3. Droplets or splatter (mucosa of the eyes, nose or mouth)
4. Inhalation (airborne microorganisms)

Question 24

What is the chain of infection starting with the source?

Answer 24

Pathogenic organism –> reservoir of source –> mode of transmission –> portal of entry –> susceptible host

Question 25

What are the four blood-borne viruses highlighted in the lecture recording? What has the highest risk of infection resulting from a needle stick from an infected patient?

Answer 25

Hepatitis B (HBV) \* highest risk of infection after needle stick Hepatitis C (HCV) Hepatitis D associated with hepatitis B HIV

Question 26

Is saliva considered to be potentially infectious?

Answer 26

Yes, saliva has always been considered potentially infectious (viruses can travel through salivary droplets)

Question 27

What is the most common mode of pathogen transmission in a healthcare setting?

Answer 27

hands/poor hand hygeine

Question 28

At what concentration of alcohol does an alcohol-based hand rub need to be in order to be considered an effective disinfectant?

Answer 28

60-95%

Question 29

What are the three reasons that gloves are warn? Do you have to wash your hands if you wear gloves? Why or Why not?

Answer 29

1. Minimize the risk of acquiring infections from patients 2. Prevent microbial flora from being transmitted from health care personnel to patients 3. Reduce contamination from one patient to another \*\*\*\*NOT A SUBSTITUTE FOR HANDWSHING, gloves can have small holes or tears that allow hands to be contaminated, or when taking off gloves hands can become contaminated

Question 30

define disinfection

Answer 30

kills of removes pathogenic organisms in a material or an object excluding bacterial spores so that they pose no threat of infection

Question 31

define szterilization

Answer 31

kills or removes all organisms and their spores in a material or an object

Question 32

what are 3 modes of sterilization?

Answer 32

heat (single strand breaks in DNA, protein denaturation and dissociate of membrane lipids) radiation (break chemical bonds and ionize molecules) chemicals (protein denaturation)

Question 33

2 types of disinfection

Answer 33

physical (filtration, UV, laser, ultrasound and sound ultrasonic) chemical (alcohols, aldehydes, biguanides, phenol based compounds, halogen based, surfactant, oxidizing agents, heavy metals)

Question 34

What are the three classes of dental instruments? Provide an example of each

Answer 34

1. **Critical**: used to penetrate soft tissue or bone, or enter into or contact the bloodstream or other normally sterile tissue (forceps, scalpels, bone chisels, scalers, and surgical burs), sterilized after each use (steam under pressure, dry heat or chemical vapor 2. **Semi-critical:** contact mucous membranes of non intact skin (mirrors, reusable impression trays and amalgam condensers), sterilized after each use (sterilization or high level disinfection) 3. **Non-critical**: contact only with intact skin (external components of x-ray heads, blood pressure cuffs and pulse ox), reprocessed between patients (intermediate or low level disinfection)

Question 35

What is the risk of having a biofilm established in water lines used for dental treatment? Where do these bacteria often originate from? (2) How might a dental office prevent biofilms in dental water lines?

Answer 35

Biofilms can serve as a reservoir, amplifying the numbers of free floating microorganisms in the water and released in aerosols **Originate from**: _water source_ (environmental organisms – harmless in immunocompetent people), _back flow_ (from dental apparatus “suck back”, opportunistic respiratory pathogens and oral bacteria) **Prevention**: independent reservoirs, chemical treatment, filtration, anti retraction valves, sterile water delivery systems, water testing, in office testing

Question 36

Why might a mouth rinse, such as chlorhexidine, be used prior to dental treatment?

Answer 36

1. Reduces number of microorganisms in aerosols/splatter 2. Decrease the number of microorganisms introduced into the blood stream