Plaque

Question 1

what are the properties of a biofilm?

Answer 1

spatially organized in a 3D structure
bacterial cells enclosed in an extra cellular matrix
increases habitat range of individual bateria

Question 2

what is the organic matrix of plaque?

Answer 2

30%
host and bacterial products
gingival area proteins from exudate

Question 3

what does the composition and behavior of organisms in the matrix depend on?

Answer 3

site
time
individuals

Question 4

what is the acquired pellicle?

Answer 4

layer of material acquired by a clean tooth
mucins/salivary glycoproteins/minerals/immunoglobulins
occurs in seconds
reaches a peak - composition/form can still change
removed by positive friction

Question 5

where do bacteria attach to?

Answer 5

attach to pellicle not enamel

Question 6

composition of pellicle?

Answer 6

mucins
PRP's
statherin
amylase
lysozyme
albumin 
immunoglobulins
GTF's
glucans

Question 7

what is initial attachment?

Answer 7

reversible/non specific interaction
long range - van der waals
short range - hydrogen bonding

Question 8

how does bacteria adhere to the pellicle?

Answer 8

ordered accumulation - pioneer to climax community

Question 9

what are glucans?

Answer 9

glucose polysaccharides with glucose molecules linked by 1-3 a or 1-6a bonds

Question 10

what are dextrans?

Answer 10

water sol glucans with 1-6a links

Question 11

what are mutans?

Answer 11

water insol glucans with 1-3 and 1-6 a links

Question 12

what are fructans?

Answer 12

fructose polysaccharides of fructose molecules joined by 2,6 B or 2,1 B links

Question 13

what are levans?

Answer 13

fructans with many 2-6 links

Question 14

what are adhesins?

Answer 14

specific molecules on bacterial surface
recognize specific ligands or receptors on tooth surface
often associated with fimbrae

Question 15

what are lectins?

Answer 15

sugar binding proteins
recognize carbohydrate groups and bind them
often associated with fimbrae

Question 16

what are fimbrae?

Answer 16

hair like proteinaceous appendages
adhesion to enamel/pellicle
adhesion to other bacteria

Question 17

stages of plaque development?

Answer 17

clean enamel surface
2 seconds - pellicle formation
1 min - pioneer bacteria
2 hours - micro colonies and extra cellular polysachh.
2 hours on - biofilm development
48 hours - mature plaque

Question 18

what bacteria appear in 24 hours?

Answer 18

gram positive and negative cocci
negative - oralis group
positive - neisseria

Question 19

after 24 hours what bacteria predominate?

Answer 19

strep - 95%

S.sanguinis most common

Question 20

what is stage 1 of succession?

Answer 20

strep attach to acquired pellicle

Question 21

what changes are seen in the biofilm in the first week?

Answer 21

increased diversity of gram positive bacteria
pioneer species reduce
actinomyces and anaerobes increase/strep decrease

Question 22

what is the second stage of succession?

Answer 22

strep is joined or replaced by actinomyces

Question 23

what is stage 3 of succession?

Answer 23

gram negative species fusobacterium joins

Question 24

what are the three types of adhesion seen in plaque?

Answer 24

cell substratum adhesion
homotypic
heterotypic

Question 25

types of heterotypic adhesion?

Answer 25

corn cob complex

test tube brush