Survey Procedures In Public Health Dentistry Question And Answers

Survey Procedures In Dentistry

Question 1. Define survey. Give its aim and objectives. Describe the scientific methods of dental survey procedure.
Or
Define oral health survey. Write in detail the scientific methodology for survey procedure.
Or
Define survey. Explain various steps conducting of survey.
Or
Write short note on steps in conducting an oral health survey.
Or
What is a survey in dental public health. Discuss in detail about various steps in conducting an oral health survey.
Or
Define and classify survey. Describe the procedural steps in survey.
Answer.

Definition of Survey

Survey is defined as the method of collection of data, analyzing and evaluating the data in order to determine the amount of disease problems and also identify cases that have not been identified.

Definition of Dental Survey/Oral Health Survey

“It is defined as survey to collect the basic information about oral diseases status and treatment needs that is needed for planning or monitoring oral healthcare programs”. —WHO

Aim of Survey

• To provide systemic approach to the collection and reporting of data on oral disease and condition.
• To ensure that data collected in a wide range of environment are comparable.
• To encourage oral health administration in all countries to make standard measurement of oral disease and condition as a basis for planning and evaluation of oral health programs.

Objectives of Survey

• The objectives of survey are initially to provide a full picture of the oral health status and needs of population.
• Subsequently, to monitor changes in disease level or patterns.

Scientific Method in Dental Survey Procedure or Dental Epidemiology

• Establishing the objective
• Designing the investigation
• Selecting the sample
• Conducting the examination
• Analyzing the data
• Drawing the conclusion
• Publishing the report.

Read And Learn More: Public Health Dentistry Question And Answers

Establishing the Objective

• The investigator must be absolutely clear about the objective of the investigation before considering its design.
• Design is entirely depend upon the objective of the survey.
• In most of the survey, the objective can be stated in the form of hypothesis which is to be tested.
• Starting point of the study is frequently an expression of a null hypothesis which explains that there is no difference between the groups.

Designing the Survey/Investigation

• A written protocol for the survey is prepared which consists of:
  • Objective and purpose of survey.
  • Description of information which is collected and methods which are used.
  • Personnel and physical arrangements
  • Use of statistical methods for analyzing the data.
  • Budget required
  • Time required for the activities
  • Staff concerned with activities
• For examining the population group, permission should be taken from the concerned authority.
• Budget should be prepared which consists of all resources for performing the survey.
• Survey teams should be equipped and ready to provide emergency care.

Selecting the Sample

• While designing a study it is usually impossible to investigate each and every individual in population.
• So to save time, money and manpower sample is used for investigation.
• In sampling the selection of sample of appropriate characteristic and adequate size is taken.
• Sample is a group of individuals who are actually available for the investigation.
• Errors are induced in data due to the factors which can be controlled. Three types of errors are—observer, instrumental and sampling error.

Conducting the Examination

Following are the steps which are to be taken while conducting the examination:

Scheduling

• Schedule should be prepared for collection of data for preventing the waste of valuable time.
• Schedule should allow for some flexibility so that unexpected delays can not lead to major problems in survey timetable.
• Time taken for examining each subject depends on the extent and detail of examination, habits and inclination of examiner.
• Two principles are considered here, i.e.
  • Examination should be automatic for obviatingexcessive intrusion of subjective thought. Examination is performed quickly.
  • In epidemiological surveys examination is done in large numbers. No extra time should be spent on individuals.

Instrument and Supply

• Plane mouth mirrors-30 in nos. for an examiner
• Periodontal probes-30 in nos. for an examiner
• Tweezers
• Containers as well as concentrated sterilizing solution
• Wash basin
• Gauze
• Cloth or paper towels.

Infection Control

Current criteria and recommendations are used for infection control and waste disposal.

Examination Method

• The basic requirement is chair with a headrest and source of illumination.
• The time for examination may ranges from few seconds to half an hour.
• The test and retest procedure are conducted to minimize intraexaminer variability.
• The inter examination variability is minimized by training calibration session.

Diagnostic aids

• According to WHO report on dental health procedure, the diagnostic aids are plane mouth mirror, sharp probe and sufficient day light.
• Classification of study depend upon diagnostic aids.

Types of examination (Dunning classification)

• Type 1: 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 lab investigation. It is very less used in public health work.
• Type 2: Limited examination with plane mouth mirror and explorer under sufficient illumination with IOPA X-ray. It is used in public health programs which provide combined service to individuals with population survey work and provide good results for pure survey work where money and time permits.
• Type 3: Inspection, examination of patient with plane mouth mirror and explorer under good illumination. Used in public health surveying.
• Type 4: Screening is done with the help of tongue depressor and available illumination. Used for the individuals which are in urgent need of treatment.

Diagnostic Criteria

These are the indices used for dental disease.

Analyzing the Data

• As the examination procedure is completed work of assembling the material as well as interpretation begins.
• Analysis consists of two components, i.e. data processing and interpretation of results.

Drawing the Conclusion

Care must be taken that the conclusion is specifically related to the investigation.

Publishing the Report

• Final step in the survey procedure is construction of report. It should be either with or without set of recommendation.
• The report must contain:
  • Statement and purpose of the survey
  • Material and methods
  • Result
  • Discussion and conclusions
  • Summary.

Question 2. What is meant by survey? What are its different types? State the advantages of survey and describe step by step the scientific pattern that should be followed in an epidemiological investigation.
Answer.

Types/Classification of Survey

There are two types of surveys i.e.

1. Descriptive or analytic
2. Cross-sectional or longitudinal.

• Descriptive survey describes a situation e.g. distribution of cancer in a population in relation to sex and age.
• Analytic survey explains the situation. It is done by formulating as well as testing the hypothesis.
• A cross sectional survey provides information related to situation which exit in a single time.
• A longitudinal survey provides data about the events or changes during a period of time.

Advantages of Survey

• It plans and evaluate health care services.
• It provides collection and reporting of data on oral diseases and conditions.
• It provides the clue for natural history of the disease.
• It helps in testing the hypothesis for prevention of disease.

Step by Step the Scientific Pattern that Should be Followed in an Epidemiological Investigation

Following is the step by step description of scientific pattern of an epidemiological investigation:

• Verification of diagnosis
  • Verification of diagnosis is the first step in an epidemiological investigation.
  • It may happen sometimes that the report can arise from misinterpretation of signs and symptoms by the lay public.
  • It is therefore necessary to have the verification of diagnosis on the spot, as quickly as possible.
  • A clinical examination of a sample of cases is carried out.
  • Laboratory investigations wherever applicable, are most useful to confirm the diagnosis but the epidemiological investigations should not be delayed until the laboratory results are available.
• Confirmation of the existence of an epidemic
  • Next step is to confirm if epidemic exists.
  • This is done by comparing the disease frequencies during the same period of previous years.
  • An epidemic is said to exist when the number of cases is in excess of the expected frequency for that population, based on past experience.
  • An arbitrary limit of two standard errors from the endemic occurrence is used to define the epidemic threshold for common diseases.
  • Often the existence of an epidemic is obvious needing no such comparison, as in the case of common source epidemics, e.g. cholera. These epidemics are easily recognized.
  • In contrast the existence of modern epidemics is not easily recognized unless comparison is made with previous experience.
• Defining the population at-risk
  • Obtaining a map of the area:
    • Before beginning the investigation, it is necessary to have a detailed and current map of the area.
    • If map is not available, it may be necessary to prepare such a map.
    • Map should contain information concerningnatural landmarks, roads and the location of all houses along each road or in isolated areas.
    • Area may be divided into segments, using natural landmarks as boundaries. This may again be divided into smaller sections. Within each section, the dwelling units, i.e. houses may be designated by numbers.
  • Counting the population:
    • Denominator may be related to the entire population or sub-groups of a population.
    • It may also be related to total events.
    • For example, if the denominator is the entirepopulation a complete census of the population by age and sex should be carried out in the defined area by house-to-house visits.
    • For these visits, health workers in sufficient numbers may be employed.
    • By this technique, it is possible to establish the size of the population.
    • Population census will help in computing the much—needed attack rates in various groups and subgroups of the population later on. Without an appropriate denominator of “population at risk” attack rates cannot be calculated.
• Rapid search for all cases and their characteristics
  • Medical survey:
    • A medical survey should be done in the defined area to identify all cases including those who have not got medical care, and those possibly exposed to risk.
    • Ideally, the complete survey will pick up all affected individuals with symptoms or signs of the disorder.
    • Employed health workers may be trained to administer the “epidemiological case sheet” or questionnaire to collect relevant data.
  • Epidemiological case sheet:
    • Epidemiologist should be armed with an “epidemiological case sheet” for collecting data from cases and from persons apparently exposed but unaffected.
    • The epidemiological case sheet or “case interview form” should be carefully designed to collect relevant information.
    • It includes: name, age, sex, occupation, social class, travel, history of previous exposure, time of onset of disease, signs and symptoms of illness, personal contacts at home, work, school and other places; special events, such as parties attended, foods eaten and exposure to common vehicles, such as water, food and milk; visits out of the community, history of receiving injections or blood products, attendance at large gathering, etc.
    • Information collected should be relevant to the disease under study. For example, if the disease is food—borne, detailed food histories are necessary.
    • A case review form will ensure completeness and consistency of data collection.
    • If the epidemic is large, it may not be possible to interview all the cases. In such cases, a random sample should be examined and data is collected.
  • Searching for more cases:
    • Patient may be asked if he knew of other cases in the home, family, neighborhood, school, work place having an onset within the incubation of the index case.
    • Cases admitted to the local hospitals should also be taken into consideration. This may reveal not only additional cases but also person-to-person spread.
    • The search for new cases (secondary cases) should be carried out every day, till the area is declared free of epidemic.
    • This period is usually taken as twice the incubation period of the disease since the occurrence of last case.
• Data analysis
  • Data collected should be analyzed on ongoing basis, using the classical epidemiological parameters, i.e. time, place and person.
  • If the disease agent is known, the characteristics of time, place and person may be rearranged into agent host–environment model.
    • Time : Prepare a chronological distribution of dates of onset and construct an “epidemic curve”. Look for time clustering of cases. An epidemic curve may suggest:
      • Time relationship with exposure to a suspected source.
      • Whether it is a common source or propagated epidemic.
      • Whether it is a seasonal or cyclic pattern suggestive of a particular infection.
    • Place: Prepare a “spot map” of cases, and if possible, their relation to possible sources of infection, e.g., water supply, air pollution, etc. Clustering of cases may indicate a common source of infection. Analysis of geographic distribution may provide evidence of the source of disease and its mode of spread.
    • Person: Analyze the data by age, sex, occupation and other possible risk factors. Determine the attack rates/case fatality rates, for those exposed and those not exposed and according to host factors. For example, in most food-borne outbreaks, food—specific attack rates must be calculated for each food eaten to determine the source of infection. Purpose of data analysis is to identify common event or experience, and to delineate the group involved in the common experience.
• Formulation of hypotheses
  • On the basis of time, place and person distribution or the agent–host–environment model, formulate hypotheses to explain the epidemic in terms of (a) possible source (b) causative agent (c) possible modes of spread, and (d) the environmental factors which enabled it to occur. These hypotheses should be placed in order of relative likelihood. Formulation of a tentative hypothesis should guide further investigation.
• Testing of hypotheses
  • All reasonable hypotheses need to be considered and weighed by comparing the attack rates in various groups for those exposed and those not exposed to each suspected factor.
  • This will lead the epidemiologist to ascertain which hypothesis is consistent with all the known facts.
  • When divergent theories are presented, it is not easy to distinguish immediately between those which are sound and those which are merely plausible.
  • Therefore, it is instructive to turn back to arguments which have been tested by the subsequent course of events.
• Evaluation of ecological factors
  • An investigation of the circumstances involved should be carried out to undertake appropriate measures to prevent further transmission of the disease.
  • Ecological factors which have made the epidemic possible should be investigated, such as sanitary status of eating establishments, water and milk supply; breakdown in the water supply system; movements of the human population, atmospheric changes, such as temperature, humidity and air pollution, population dynamics of insects and animal reservoirs.
  • The outbreak can be studied in a case control fashion.
  • One of the primary concerns of the epidemiologist is to relate the disease to environmental factors to know the source of infection, reservoirs and modes of transmission.
• Further investigation of population at risk
  • A study of the population at risk or a sample of it may be needed to obtain additional information.
  • This can involve medical examination, screening tests, examination of suspected food, feces or blood samples, biochemical studies, assessment of immunity status, etc.
  • The approach may be retrospective or prospective.
  • Healthy individuals from the same universe may be studied in a case control fashion.
  • This will permit classification of all members as to:
    • Exposure to specific potential vehicles.
    • Whether ill or not.
• Writing the report
  • The report should be complete and convincing.
  • Information to be included in the final report on an epidemic is given.

Question 3. Write shot note on pilot survey.
Answer. Pilot survey is a type of pathfinder survey.

A pilot survey is one that includes only the most important subgroups in the population and only 1 or 2 index ages, usually 12 years or one another age groups. 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.

Question 4. Write short note on screening.
Answer. Screening is defined as “the use of presumptive methods to identify unrecognized health risk factors or asymptomatic disease in persons determined by prior studies to be potentially at elevated risk and able to benefit from interventions performed before overt symptoms develop”. —WHO (1994).

Uses of Screening

• Case detection (prescriptive screening): The presumptive identification of unrecognized disease which does not arise from a patient’s request, i.e. people are screened for their own good.
• Control of disease (prospective screening): People are examined for the benefit of others.
• Research purposes: For many chronic diseases whose natural history is not fully known. Participants should be informed that no follow-up therapy will be available.
• Educational opportunities: Opportunity for creating public awareness and for educating health professionals.

Types of Screening

• Mass screening: It is the screening of a whole population or a subgroup. There is no reference to risk and usually no follow-up. It is performed in a community setting.
• High risk or selective screening: It is done to detect a specific disease or predisposing condition in people who are known to be at high risk of having or developing the condition.
• Multiphasic screening: It is the application of two or more screening tests in combination to a large number of people at one time.
• Opportunistic screening: It is done only when the opportunity arises, it is usually done in a clinical setting.
• Two-stage screening: It is conducted on those who screen positive the first time and are recalled for further testing. This process is less expensive as the less invasive and less uncomfortable test is done first.

Criteria for Screening

• The condition should be an important health problem.
• There should be an acceptable treatment for patients with recognized disease.
• Facilities for the diagnosis and treatment should beavailable.
• There should be a recognizable latent or early symptomatic stage so that individuals benefit by early detection.
• There should be a suitable test or examination.
• The natural history of the condition, including development from latent to declared disease, should be adequately understood.
• There should be an agreed policy concerning who to treat as patients.
• The cost of case finding should be economically balanced in relation to possible expenditure on medical care as a whole.
• The test should be acceptable to the population.
• Case finding should be a continuous process and not a “one off” procedure.
• There is a substantial burden of the disease in the community.

Question 5. Write short note on pathfinder survey.
Or
Write short answer on pathfinder survey.
Answer. Pathfinder survey incorporates sufficient examination sites to cover all important subgroups of population which can have different disease levels or treatment needs and at least three of age groups or index ages.

Pathfinder surveys can be classified as either pilot or national depending on the number of sample sites, age groups or index ages included.

A pilot survey is one which includes most important subgroups in the population and only one or two index ages usually 12 years and one another age group. Such survey provides minimum amount of data which is needed to commence the planning.

National pathfinder survey is suitable for collection of data for planning as well as monitoring the services in all countries whatsoever be the level of disease, availability of resources or complexity of services.

Pathfinder survey is suitable for obtaining following information:

• Overall prevalence of common oral diseases and condition affecting population.
• Variation in disease level, severity and need of treatment in subgroups of population. This enable group in special need of services to be identified.
• Age profile of oral diseases in population to enable careneeds for different age group to be determined, to provide information about severity and progression of disease, and to give an indication as to whether the levels are increasing or decreasing.

Question 6. Write short answer on descriptive survey.
Answer. Descriptive survey describes a situation e.g. distribution of cancer in a population in relation to sex and age.

• Analytic survey explains the situation. It is done by formulating as well as testing the hypothesis.
• Distinction between a descriptive and analytic survey is not always clear and a single survey can combine both purposes. Example is a broad descriptive survey may be so planned, that it also provides information for the testing of a specific hypothesis.

Uses

• Monitoring trends in oral health and disease: When the national surveys get repeated periodically under the similar conditions, broad oral health trends over time can be estimated, provided the sampling design permits. Usually, a single survey can reveal how the oral health varies by geographic region, social class or via race or ethnic group.
• Development policy: The survey data is used to establish the oral health strategies.
• Program evaluation: Survey data is used to evaluate program but the principle that association does not show cause and effect always need to be remembered. Success of particular programs can only be inferred from the survey data, more localized the survey and programme, more plausible is the inference.
• Assessment of dental needs: Surveys can be used for assessment of needs, there is clear gap between criteria used in surveys and those applied for individual patient care.
• Provide visibility to dental issues: Visibility which acquires through mere existence of data from national survey can be most important of all uses of survey data.