Microbiology for dentists theme 2b

Question 1

What is the DMFT index ?

Answer 1

Measure of the decayed, missing and filled tooth surfaces

cumulative caries and treatment experience

Question 2

How do we measure the DMFT index ?

Answer 2

if a tooth is decayed, missing or filled it gets a score of 1
otherwise 0
score out of 32 if 8s present

Question 3

What does the DMFT index exclude ?

Answer 3

teeth that are congenitally missing
teeth extracted for ortho/perio reasons
trauma
supernumerary teeth

Question 4

If a tooth is decayed and filled which score would you give it ?

Answer 4

1

Question 5

What are limitations of the DMFT index ?

Answer 5

gives equal weighting to missing, untreated and well restored teeth
only takes into account caries
fissure sealants given same weighting as restored teeth
rate not assessed nor risk

Question 6

Which plaque index is most used ?

Answer 6

Plaque coverage index

Question 7

What are some examples of plaque indices ?

Answer 7

Silness and Loe index

plaque coverage index

Question 8

What does the plaque index measure ?

Answer 8

the number of surfaces with plaque as a percentage of total tooth surfaces

Question 9

How do we carry out the plaque coverage index ?

Answer 9

divide tooth into 6
say yes or no
cross out missing teeth
dont measure occlusal surfaces

Question 10

Which 6 surfaces would a mandibular tooth be divided into ?

Answer 10

MB
Mid buccal 
DB
ML
Mid lingual 
DL

Question 11

In what order should you measure the plaque ?

Answer 11

UB
UP
LB
LL

Question 12

How would you calculate the plaque coverage index ?

Answer 12

total number of surfaces = number of teeth x 6
count all plaque surfaces
number of plaque surfaces/ total number of tooth surfaces x 100

Question 13

What are disclosing tablets ?

Answer 13

veegtable dye used to stain plaque deposits
older tablets stain all plaque pink
new tablets stain new plaque pink and old plaque blue

Question 14

What does the Silness and Loe index measure ?

Answer 14

the amount of plaque on surfaces

Question 15

Which scores are used in the SL index ?

Answer 15

0- no plaque
1- film of plaque visibe only by removal
2- moderate accumulation visible by naked eye
3- Heavy accumulation

Question 16

How would you calculate the SL index ?

Answer 16

Add up all scores
total number of surfaces
Total S and L score/ total surfaces x 100

Question 17

What is epidemiology ?

Answer 17

the scientific method of studying diseases in populations

Question 18

What are the 3 components of epidemiology ?

Answer 18

distribution
frequency
determinants

Question 19

What is the process of finding a relationship ?

Answer 19

suspicion 
hypothesis 
tested with comparison group
analyse data 
assess validity

Question 20

What is the gold standard for measuring disease ?

Answer 20

is the method of measuring valid, simple, reliable and reproducible ?

Question 21

What is the difference between DMFT and dmft ?

Answer 21

permanent and primary dentition

Question 22

What do indices allow ?

Answer 22

standardisation universally

Question 23

What does reliable mean ?

Answer 23

get the same result each time

Question 24

What does reproducible mean ?

Answer 24

calibrated

Question 25

What does sensitive mean ?

Answer 25

detect minute changes

Question 26

Why do methods of maesuring disease have to be acceptable ?

Answer 26

they need to be done correctly to reduce chances of iatrogenic damage

Question 27

What are case studies for ?

Answer 27

highlighting interesting cases in recognition of a new disease there is no control- so no comaprsion which can effect validity of the relationship

Question 28

What is a case series ?

Answer 28

a report on a single patient or series of patients with an interest no control group is required

Question 29

What are the limitations of case studies ?

Answer 29

they might be standalone cases | cant compare and make links and prove

Question 30

What is a cross sectional study ?

Answer 30

used for prevalence of disease can find out potential risk factors can establish an association and not a causality observation of a population in a single point in time

Question 31

What are cohort studies ?

Answer 31

``` 2 groups side by side one with exposure and one without assess the results in time later use for common diseases blinding is difficult not good for rare diseases ```

Question 32

What are randomised controlled trials ?

Answer 32

evaluate the effectiveness of something like a drug 2 groups- one receives treatment the other a placebo (current best) very expensive randomisation used for selection bias high cost and ethical issues

Question 33

What are systematic reviews ?

Answer 33

``` pool all studies and give an average result - uses exclusion and inclusion criteria asses the strength of the evidence end confusion highlight when not eniugh evidence save money by saying research is done ```

Question 34

Epidemiology in dentistry operates in which 3 broad fields ?

Answer 34

1. measurement of dental disease among groups to understand distribution 2. identification of factors that cause conditions 2. evaluation of effectiveness of new materials

Question 35

What does reliable mean ?

Answer 35

measurements are taken on different occassions the same answer is obtained

Question 36

What are descriptive studies ?

Answer 36

describe the pattern of disease risk factors dterminants

Question 37

What are analytical observational studies ?

Answer 37

go back in time or forwards- retrospective or prospective

Question 38

What are case control studies ?

Answer 38

people with the interest identified matched with controls questioned about what risk factors could have led to condition

Question 39

What are analytical experinental studies ?

Answer 39

randomised clinical trials

Question 40

What is prevalence ?

Answer 40

proportion of individuals in a population who have a disease at a specific instant

Question 41

How do you work out prevalence ?

Answer 41

number of existing cases of disease/ total population

Question 42

What does prevalence provide ?

Answer 42

an estimate of probability an individual will be ill at any time

Question 43

What is incidence ?

Answer 43

number of new cases of disease during a given time period

Question 44

What is cumulative incidence ?

Answer 44

number of new cases of a disease during a given time period/ total population at risk

Question 45

How do you work out incident rate ?

Answer 45

number of new cases of disease during a given time period/total person time observation

Question 46

How can you work out person time ?

Answer 46

addition of all the hours that everyone contributes

Question 47

What is an index ?

Answer 47

measures the relative disease status of a population on a graudutsed scale with definite upper and lower limits

Question 48

What do indices allow ?

Answer 48

allow comparison with other populations- universal evaluate success of a treatment compare health status

Question 49

What are the characterisitics of an ideal index ?

Answer 49

equally sensitive simple to apply valid reliable

Question 50

What does valid mean ?

Answer 50

it measures what it says it measures

Question 51

What is bias ?

Answer 51

a systematic error relating to the measurement of a variable were the groups similar at the start, were they balanced and effectively masked ?

Question 52

What is confounding ?

Answer 52

an error in the interpretation of a measurement | eg. saying things are linked when they are not

Question 53

How can we manage confounding ?

Answer 53

randomisation stratifying matching using statistical analysis

Question 54

What is the dmft index ?

Answer 54

for the primary dentition

Question 55

What is the DMFT index ?

Answer 55

for the permanent dentition

Question 56

What is the IOTN ?

Answer 56

index of orthodontic treatment need

Question 57

What is RCI ?

Answer 57

root caries index

Question 58

What are problems with the DMFT ?

Answer 58

missing teeth could have been perio, developmental or trauma filled teeth might be for prevention and not caries score is irreversible- cant be used to show improvement