Post on 26-Dec-2015
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Preventive dentistry
6 1 4
4 1
6
Ramfjord index teeth
( 2 ) Turesky Modification of the Quigley Hein Index
Preventive dentistry
0=No plaque
1=Slight flecks at the cervical margin
2=thin continuous band (≤1 mm) at cervical margin
( 2 ) Turesky Modification of the Quigley Hein Index
Preventive dentistry
3 = A band of plaque >1 mm but < 1/3 of the area
4 = covering 1/3 - 2/3 of the area
5 = covering ≥ 2/3 of the area
( 2 ) Turesky Modification of the Quigley Hein Index
Preventive dentistry
( 3 ) GI ( Löe and Silness )
0 No inflammation. Normal gingivae
1Mild inflammation – slight change in colour, slight edema. No bleeding on probing.
2Moderate inflammation – redness, edema and glazing. Bleeding on probing.
3Severe inflammation – marked redness, edema. Ulceration. Tendency to spontaneous bleeding
Preventive dentistry
( 4 ) CPI
17 16 11 26 27
47 46 31 36 37
16 11 26
46 31 36
≥20 years old 15 ~ 20 years old
Preventive dentistry
0 = Healthy1 = Bleeding observed2 = Calculus detected, all the black band
visible3 = Pocket 4-5 mm
( 4 ) CPI
Preventive dentistry
4 = Pocket ≥6 mm (black band not visible)X = Excluded sextant ( <two teeth )9 = not recorded
( 4 ) CPI
Preventive dentistry
15 years old
Feature of distribition
Sextant Grade
0.0 ~ 1.5
1.6 ~ 2.5
2.6 ~ 3.5
3.6 ~ 4.5
4.6 ~ 6.0
Very low
Low
Middle
High
Very high
Preventive dentistry
Feature of distribition
1 Area
Developing Vs Developed countriesRural Vs Urban
2 time
Preventive dentistry
oral hygiene smoking ( duration 、 frequency 、 typ
e )nutrition systemic diseases
Related factors
Preventive dentistry
Other oral diseases epidemiology
Oral cancerDental fluorosisCleft lip and palateDentofacial anomaliesOral mucosal diseases
Preventive dentistry
Oral cancer
China 0.7 , Thailand 4.6 , India 12.6 /100,000
District: one of the most common tumor in east south Asia
Time, ageGender: male > femaleRace
Preventive dentistry
Oral cancer
DistrictTime, ageGender: male > femaleRace
口腔癌
Preventive dentistry
Dental fluorosis
Dean’s index
Based on the 2 most severely affected teeth (record the status if they are the same and record the less severe if they are not)
Preventive dentistry
Dental fluorosis
0 Normal
0.5 Questionable (few flecks, occasional spots)
1 Very mild (opacities<1/4 of surface)
2 Mild (opacities<1/2 of surface)
3 Moderate (may have brown stain)
4Severe (pitting, hypoplasis and brown stain)
Preventive dentistry
Dental fluorosis
Fci = ( n×W ) / N
Fci= 〔 (0.5× Questionable)+(1× Very mild )+…+(4× Severe )×100 %〕 / N
Preventive dentistry
Dental fluorosis
Public health significance
0-0.4 Negative
0.4-0.6 Borderline
0.6-1.0 Slight
1-2 Medium
2-3 Marked
3-4 Very marked
Preventive dentistry
Cleft lip and palate
One Cleft lip or palate case per 500 ~ 700 infants
factors
Preventive dentistry
The survey and evaluation of oral health
Purpose Item IndexMethodSample sizeError and prevention
Preventive dentistry
Questionnaire data collection
Collect information that cannot be observed.
knowledge
attitude practice
belief
Preventive dentistry
Methods
Census (普查) ----a complete enumeration of the umits to be studied (mass examination)
: no sampling error
: not practical, time consuming
Preventive dentistry
Sampling
--measurements on part of the population
--less resource demanding
--quicker to complete
--more cost-efficient
--detail examination possible
Preventive dentistry
Sampling Methods
Most important issue is whether the sample can adequately represent the bigger population
Simple random sampling 单纯随机抽样 Systematic sampling 系统抽样 Stratified sampling 分层抽样 Cluster sampling 整群抽样
Preventive dentistry
Simple random sampling
sample
population
Draw lots, throw a die Random number table Computer generated random number
Preventive dentistry
Systematic sampling
In a list select every u unit in a list starting from a random number ( from 1 to uth)
U+k U+2kU
N1
Preventive dentistry
Stratified sampling
Subdivide the population into strata and draw sample from each stratum independently
Common strata: age, gender, districts, etc
sample sample
population
Preventive dentistry
Cluster sampling
Subdivide the population into several clusters (blocks of units)
All elements in these selected cluster are studied
population
cluster cluster cluster
sample
Preventive dentistry
Multi-stage sampling
Sampling can take place in stages by repeating or combining the above sampling
More efficient for large scale surveys
Preventive dentistry
Pilot survey
Include only one or two age groups to collect the minimum amount of data
12 years +one other age group
Preventive dentistry
OH survey ----pathfinder
to include the most important population subgroups
A stratified cluster sampling techniqueVariations in level, severity and need
Preventive dentistry
Index age groups
5 yrs children ( primary teeth)12 yrs children ( permanent ) 15 yrs adolescents35-44 yrs adults65-74 yrs elders
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Sample size
N=K×Q/PN subjects, p proporationQ=1 - P
KType II error
400 10%
178 15%
100 20%
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Error and bias
Selection bias (选择性偏倚)
Unresponse bias (无应答偏倚)
Information bias (信息偏倚)
Preventive dentistry
Information bias
K (Kappa)
reliability
< 0.4 poor
0.41~0.60 medium
0.61~0.80 good
0.81~1.0 excellence
Calibration ( 标准一致性试验)