Survey Lecture
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Transcript of Survey Lecture
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Survey in dentistry
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INTRODUCTION
The first step in modern public health procedure
parallels that used by the dental clinician, only here
it is th
e community th
at must be examined. It iscalled a survey instead of an examination.
Whatever the specific problem, the initial approach
to its solution should involve an examination to
determine its dimensions and particularcharacteristics.
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Survey
Definition: "Survey is defined as "The method of
collection of facts or information about the status-
quo of large number of cases in the community".
Dental survey means "Collection of facts and
analyzing and evaluating them and comparing that
data to previous data collected with that of
different place".
or
Basic oral health surveys are defined as "Surveys to
collect the basic information about oral disease
status and treatment needs that is needed for
planning or monitoring oral health care
Programmes".
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SURVEY:
A survey is an investigation in which information
is systematically collected, but in which
experimental method is not used. There is no
active intervention. Surveys are methods for
collection of data, analyzing and evaluating them
.in order to determine the amount of disease
problems in a community and also to identify
cases that have not been identified.
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Aims of the Survey
1. To provide systematic approach to the
collection and reporting of data on oral
diseases and conditions.
2. To ensure that data collected in a wide rangeof environments are comparable.
3. To encourage oral health administrators in all
countries to make standard measurements of
oral diseases and conditions as a basis forplanning and evaluation oral health
programmes.
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Uses of Survey
1. Community diagnosis of problems of health
and disease.
2. Collection of data to describe in normalbiological factor.
3. Understanding the natural history of the
disease.
4. Testing of hypothesis for the prevention ofdiseases (dental).
5. Planning and evaluating health care services.
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Advantages:
1. Provide information on some aspects of oralhealth about which information may not be
available from any source,
2. Rates and indices can be calculated.
3. Associations and correlations can be identifiedand studied.
4. Reasons' for utilization as well as non-utilization
of oral health services can be studied.
5. Information from a well-planned6. complete and accurate compared to information
collected routinely.
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Types of Surveys
Descriptive: It sets out to describe a situation
Cross-sectional
Longitudinal
Analytic (explanatory): Tries to explain the
situation, that is to study the determinative
process
Cross-sectional
Longitudinal
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Pathfinder SurveyIt is a practical, economic survey sampling
methodology. The method used is a stratified
cluster sampling technique, which aims to
include th
e most important populationsubgroups likely to have differing disease levels,
and to cover a standard number of subjects in
specific index age groups in any one location.
In this way, statistically significant and clinically
relevant information for planning is obtained at
minimum expense.
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This methodology is suitable for obtaining the
following information:
1. Prevalence of the various oral diseases affecting
the population.
2. Important variations in disease level, severity andneed for treatment in subgroups of the population.
3. A picture of the age profiles of oral diseases in the
population to provide information about severity and
progression of disease, and to give an indication as lowhether the levels are increasing or decreasing.
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Pathfinder Survey is classified! as either pilot or national.
Pilot Survey is one that includes only the most importantsubgroups in the population and only 1 or 2 index ages, usually
12 years and one other age group. Such a survey provides the
minimum amount of data needed to commence planning.
Additional data should then be collected in order to provide a
reliable baseline for the implementation and monitoring of
services.
National Pathfinder Survey incorporates sufficient examination
sites to cover all-important subgroups that may have differingdisease levels or treatment needs and at least three of index
ages. This type of survey design is suitable for the collection of
data for the planning & monitoring of services in all countries.
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Number of subjects
The number of subjects in each index age
group to be examined ranges from a minimum
of 25 to 50 for each cluster or sampling site,
depending on the expected prevalence and
severity of disease.
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An example of a sample design for a national
pathfinder survey for each index age or age group is as
follows:
Urban: 4 sites in capital city (4 x 25) = 100 2 sites in
each of 2 large towns (2x2x25) = 100
Rural: 1 site in each of-1 villages in different regions
(4 x 25) = 100
Total: 12 sites x 25 subjects = 300
Applying this cluster distribution to the entire
population (index ages like 12, 15,35 to 44, 65 to 74
years), the total sample is 4 x 300 = 1200.
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Index Age and Age Groups
Those recommended are 5 years for primary teeth,
12, 15, 35-44, 65-74 years for permanent teeth. In
each age group minimum of 25-50 subjects is to be
considered.3
5 years: This age is of interest in relation to levels of
caries in the primary dentition which may exhibit
changes over a shorter time span than thepermanent dentition at other index ages.
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12 years: This is the age at which children leaveprimary school, and is also the last age at which
reliable sample may be obtained easily through
the school system. At this age all permanent
molars would have erupted except the thirdmolars. This age is also chosen as the global
monitoring age for caries for international
comparisons and monitoring of disease trends.
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15 years: At this age the permanent teeth have
been exposed to th
e oral environment for 3 to 9years. The assessment of caries prevalence is
therefore often more meaningful than at 12 years
of age. This age is also important for the
assessment of periodontal disease indicators inadolescents.
35 to 44 years: This age group is the standard
monitoring group for health conditions of adults.
The full effect of dental caries, the level of severeperiodontal involvement and the general effects
of care provided can be monitored in this age
group.
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65 to 74 years: This age group has becomemore important with the changes in age
distribution and increases in life span. Data for
this group are needed both for planning
appropriate care for the elderly and formonitoring overall effects of oral care services.
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Scientific Method In Dental Epidemiology
1. Establishing the objective.
2. Designing the investigation.
3. Selecting the sample.4. Conducting the examinations.
5. Analyzing the data.
6. Drawing the conclusions.
7. Publishing the reports.
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Establishing the Objective
The surveyor must be absolutely clear about the
objective of the survey before considering its design.
Design is entirely dependent upon the objective of
th
e survey.In most of the survey, the objective can be stated in
the form of hypothesis which is to be tested. The
hypothesis can be the difference in external of the
dental disease between two different groups or in acase of clinical trials, that one method is then
another in preventing or treating a disease. The
object of the survey is then to test this hypothesis.
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Designing the Survey
This can be taken through different studies. They are:
Prevalence study also called as cross-sectional study:
It is the proportion of population suffering from a
particular disease in a given time in a given population.
It is useful to compare the diseases in population at
different time.
B. Incidence or longitudinal study: Where the amount
of new disease is a population is measured over a
period of time. This is usually expressed as the
proportion of that population which becomes affected
per unit time.
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Clinical trials:When a new treatment has been developed it is
important to provide the answer to two questions
before making decision.
Does it work?
Is it better than existing treatment?
To answer these questions, the clinical trial survey is
carried' out.
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Conducting the Examination
For scientific epidemiological study of dental
diseases and conditions, three aspects are of great
importance. They are ,
examination methods,
diagnostic aids and
diagnostic criteria.
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a.Ex
amination method:
The basic requirement is a chair preferably with
a headrest and source of illumination. The time for
examination may range from 30 seconds to one andhalf an hour depending upon the study.
Test and retest procedures are conducted to
minimize intra-examiner variability. Tests and
retests are examina-tion of patient two times andcomparing monthly. The intra-examiner variability is
minimized by training calibration session.
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b. Diagnostic aids:
According to WHO report on dental health
procedure, the diagnostic aids are plane mouth
mirror, sh
arp probe and sufficient day ligh
t.D
unning(1971) classifies the studies into 4 groups depending
upon the type of use of diagnostic aids.
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TYPE I: Complete examination with plane mouth
mirror and explorer under sufficient illumination
with full mouth radiographs. Additional diagnostic
aids are study cast, pulp testing and other
laboratory investigation.
Type II: Limited examination of patient with plane
mouth mirror and explorer under sufficient
illumination with bitewing X-rays and IOPA X-rays.
Type III: Examination of patient with plane mouth
mirror and explorer under good illumination. It is
commonly practiced.
Type IV: It is screening procedure, with the help of
a tongue depressor and available illumination.
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c. Diagnostic criteria:
These are the indices used for dental diseases.The indices should have the following properties:
Clarity
Simplicity
ObjectivityValidity
Reliability
Quantifiability
AcceptabilitySensitivity.
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Analysing the Data
This is done with the help of statistical
measurements, like range, mean deviation,standard deviation, mean, mode, median, bar
diagram, histogram.
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Drawing the Conclusion and Publishing the Report
This is taken under following headings:
a. Introduction: This tells about the diseases to be
studied.
b. Review of literature: Past literatures about the diseases
taken for survey are mentioned.
c. Materials and methods: This includes selection
and description of samples and methods used in
survey together with its criteria.
d.R
esults:Th
ese sh
ould be tabulated and illustrated asappropriate, with amplifications in the text.
e. Discussion and conclusion: The survey, its findings and
its conclusion are discussed at the discretion of the
survey.
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Thanks