caries aetiology

Question 1

what is aetiology?

Answer 1

study of the cause of a disease

Question 2

what is needed for caries development?

Answer 2

• tooth surface
• plaque biofilm
• time
• sugar

Question 3

what causes demineralisation?

Answer 3

when plaque uses dietary sugar to produce acids

Question 4

where are the most common surfaces affected by caries?

Answer 4

• pits and fissures
• approximal surfaces (at or below contact points)

Question 5

what would smooth surface caries indicate?

Answer 5

high caries rate

Question 6

what does the plaque need to be before producing acids?

Answer 6

dysbiotic plaque

Question 7

what sugars are needed to cause caries?

Answer 7

fermentable carbohydrates
- frequent
- amount

Question 8

what bacterial acid is produced by plaque?

Answer 8

lactic acid

Question 9

how can caries progression be modified?

Answer 9

• biofilm disruption- fluoride and tb
• environment of biofilm- diet

Question 10

what is the specific plaque hypothesis?

Answer 10

small number of specific organisms cause disease
- if absent- no disease
- specific tx targets- vaccine, antibacterials.

Question 11

what is a key species associated with caries (is it specific plaque hypothesis??) ? likely??

Answer 11

streptococcus mutans
- however, people with caries sometimes don’t have s.mutans
- and can be found in biofilm of caries free patients

Question 12

what is the non-specific plaque hypothesis ? likely???

Answer 12

all microorganisms in the biofilm contribute to disease- not specific

• not likely as all bacteria would need to be removed and most people would have caries as its hard to remove all plaque

Question 13

what is marsh’s ecological plaque hypothesis ?

Answer 13

cariogenic bacteria are ubiquitous (always there) in plaque- but at too low concentrations to cause disease. Requires a shift in the balance driven by local environmental change (so there is more)

Question 14

what is the local environmental changes highlighted in marsh’s ecological plaque hypothesis?

Answer 14

availability of sugars

Question 15

what is the ecological shift of plaque bacteria?

Answer 15

shift in bacteria to withstand acids (adaptation) and produce acids (selects)- dysbiosis

Question 16

what is the Stephan curve?

Answer 16

it shows what happens to the pH with sugar consumption- and how it favours demineralisation when the pH drops below the critical level.

Question 17

what is the critical pH level?

Answer 17

5.5

Question 18

what does falling above or below the critical pH mean?

Answer 18

above- potential remineralisation

below- demineralisation

Question 19

name each part of enamel caries

Answer 19

Question 20

what zone of enamel caries is the most demineralised?

Answer 20

body of the lesion zone

Question 21

what are early signs of demineralisation?

Answer 21

WSL’s

Question 22

what is needed for detection of caries?

Answer 22

• dry teeth
• remove plaque (clean)
• well illuminated

Question 23

do enamel white spots always mean caries?

Answer 23

NO

• developmental issues

Question 24

how does dentine respond to early enamel lesions?

Answer 24

• fill tubules with more mineral- prevent acid from passing through
• produce secondary/tertiary dentine to protect the pulp

Question 25

when dentine is infected why does it keep its structure?

Answer 25

because of the matrix- the dentine is demineralised so it loses its strength but it holds its shape due to the Matrix. Necrotic dentine has lost its matrix- but zone of bacterial invasion still has the matrix and is not yet broken down.

Question 26

name each part of dentine caries

Answer 26

Question 27

what is the advancing front zone of the dentine?

Answer 27

the demineralised zone (matrix remains and shape is maintained but loses its strength)

Question 28

what part of the dentine caries is contaminated?

Answer 28

- necrotic zone (matrix broken down) - contaminated zone (matrix remains but bacteria present)

Question 29

what is the translucent zone?

Answer 29

the hard/sound dentine

Question 30

where does caries spread rapidly?

Answer 30

along the ADJ

Question 31

what is the purpose of saliva with caries?

Answer 31

- it is alkaline- so acts as a neutraliser - acts as buffer- returns pH to neutral before it can go below the critical pH - antibacterial components

Question 32

why is saliva good for remineralisation?

Answer 32

because it contains calcium and phosphate and fluoride- needed for remineralisation

Question 33

what does fluoride do to enamel?

Answer 33

- changes OH ions of hydroxappetite with fluoride ions- to form flourappetite-

Question 34

what happens to the critical pH when forming fluorappetitie ?

Answer 34

critical pH is lowered - demin needs lower pH - resin can happen at lower pH -reduces demin and increases remin and increases speed of remin

Question 35

what is the most important etiological factor when it comes to controlling caries?

Answer 35

diet and availability of sugars

Question 36

what drives dysbiosis of plaque biofilm?

Answer 36

diet and oral sugar availability

Question 37

what are methods for detecting caries?

Answer 37

- radiographs - direct vision - transillumination - orthodontic separators

Question 38

at what age can bitewings be used?

Answer 38

age 4 and above as part of examination unless dentition is spaced/low caries risk

Question 39

when should bitewings be taken for high risk children?

Answer 39

6-12 months

Question 40

when should bitewings be taken for low risk children?

Answer 40

12-18 months for primary teeth and 2 years for permanent teeth

Question 41

what do arrest enamel WS lesions look like?

Answer 41

smooth/shiny

Question 42

what do active enamel WS lesions look like?

Answer 42

rough and frosty

Question 43

what eventually happens to carious dentine which keeps its shape due to collagen matrix?

Answer 43

-proteolytic bacteria eventually breaks down to matrix- overlying enamel loses its support and fractures= cavitation

Question 44

how can dentine caries become arrested?

Answer 44

- if cavitated, the dentine will be exposed to oral environment and if diet modifications work/ability to Clean well with tb- plaque biofilm will not have substrate to progress

Question 45

in a child, what considerations should be taken when considering wether to restore caries?

Answer 45

assess risk of lesion causing pain: - exfoliation time - ability to cleanse cavity with tb - activity of lesion - proximity to pulp - cooperation of parent/child

Question 46

describe the international caries detection and assessment system

Answer 46

Question 47

what is the difference between sensitivity and specificity of diagnostic tests?

Answer 47

sensitivity- ability of a test to detect disease specificity- ability of a test to not falsely detect disease

Question 48

what factors show increased risk of dental caries in children?

Answer 48

- previous caries - socioeconomic status - s.mutans levels - lactobacilli levels - siblings/parents caries levels - salivary flow rates - DMFT - DMFS