Depending upon the time period covered by the observations they can be Longitudinal Cross section
BASIC ORAL HEALTH SURVEYS:- Are defined as survey to collect the basic information about oral disease status & treatment needs that is needed for planning or monitoring oral health care programmes. note
Surveys are not designed to collect information about clinical effectiveness of different preventive or care procedures or etiological factors affecting disease distribution or severity.
However the information obtained can be used for monitoring the effectiveness of oral care services.
OBJECTIVES OF ORAL HEALTH SURVEYS:- Initially to provide a full picture of the oral health status & needs of a population. Subsequently to monitor changes in disease levels or patterns.
PATHFINDER SURVEY:- Special factors associated with the most common oral diseases & the extensive experience gained in oral epidemiology over the past 25 years have enabled a practical, economic survey sampling methodology to be defined – “PATHFINDER” method.
Method used is “stratified cluster sampling technique” which aims to include the most important population subgroups likely to have different disease levels. It also proposes appropriate number of subjects in specific index age groups in any one location.
In this way reliable & clinically relevant information for planning is obtained at minimum expense.
It is suitable for obtaining the following information:- The overall prevalence of the common oral diseases & conditions affecting the population. Variations in disease in the population enable case needs for different age groups to be determined, to provide information about severity & progression of disease & to give an indication as to whether the levels are increasing or decreasing. PREVALENCE Refers to all current cases(old & new) existing at a given point in time or over a period of time in a given population.
PATHFINDER SURVEYS CAN BE EITHER PILOT SURVEY NATIONAL PATHFINDER SURVEY PILOT SURVEY:- Is one that includes only the most important subgroups in the population &only 1 or 2 index ages usually 12 yrs or one another age gr. This survey provide minimum amount of data needed to commence planning . Additional data has to be collected in order to provide a baseline for the implementation & monitoring of services. NATIONAL PATHFINDER SURVEY:- Incorporates sufficient examination sets to cover all important subgroups of the population that may have differing disease levels or treatment needs & at least 3 of the age groups or index ages. This type of survey is suitable for the collection of data for the planning & monitoring of services.
INDEX AGE & AGE GROUPS:- Recommended ages are- 5 year for primary dentition 12,15 ,35-44 & 65-74 for permanent dentition 5th year- in relation to levels of caries in the primary dentition which may exhibit over a shorter time span. 12th year–age at which children leave primary school therefore it is last age at which reliable sample may be obtained easily through the school system. All perm. Teeth have erupted except 3rd molars- for this reason it has been chosen as “Global Monitoring Age” for caries for international comparisons & monitoring of disease trends.
15th year-at this age the permanent teeth have been exposed to the oral environment for 3-9 years. 35-44 years-standard monitoring group for health conditions of adults. Full effect of caries , periodontal disease involvement & general effects of the care provided can be monitored using data for this age group. 65-74 years-data for this group is necessary for planning appropriate care for the alderly & for monitoring the overall effects of oral care services in a population.
SURVEY PROCEDURES ESTABLISHING THE OBJECTIVES DESIGNING THE INVESTIGATION SELECTING THE SAMPLE CONDUCTING THE EXAMINATION ANALYSING THE DATA DRAWING THE CONCLUSIONS PUBLISHING THE RESULT
ESTABLISHING THE OBJECTIVES Hypothesis ,an assumption is the basis according to which objectives has to be established. B. DESIGNING THE INVESTIGATION Types of study – a. Descriptive b. Analytical There are two main subdivisions of both:- Prevalence Study / Cross sectional- Where the occurrence of a disease or condition in a population is expressed at a given point in time. Used for making comparisons b/w two or more population or b/w the same population of different time.
Incidence (Longitudinal) Study- Where the amount of new disease in a population is measured over a period of time. Usually expressed as the proportion of the population which become affected per unit of time. It is concerned with events which happen during the investigations. By this study we can measure the extent of the new disease ,often refer to as the increment. Prevalence- condition existing at a particular point in time. Incidence – change in a condition over a period in time. Controls:- A parallel group not exposed must also be studied in the same way called group. Importance- in order to avoid argument & implies a cause & effect relationship without further substantiation.
METHODS OF STUDY:- Can be of two types:- a. Case control study b.Cohort study CASE CONTROL(RETROSPECTIVE) COHORT STUDY(PROSPECTIVE ) Starting point is a group with disease investigation. Assessment is made of the factors which have influenced these subjects in the past& which might be associated with disease & findings are compared with those from a suitable control. Starts with a population of individuals classified according to the various factors of interest. During a follow up period assessment is made of the influence that these factors may have on the occurrence of the disease.
C.SELECTING THE SAMPLE It is impossible to examine every individual in the population.(manpower ,money, time ,are considered) TYPES:- SELECTED SAMPLE RANDOM SAMPLE CLUSTER SAMPLE STRATIFIED RANDOM SAMPLE SAMPLING BY STAGES
SELECTED SAMPLE A criteria is set if a person fulfills the criteria he is selected for the sample Selection may be done either by Self selected- which is haphazard or systematic Research workers RANDOM SAMPLE Where each individual have an equal chance of being included in the sample. CLUSTER SAMPLE Done for administrative & economic reasons Clusters may be villages , buildings ,classes of schoolchildren or family.
STRATIFIED RANDOM SAMPLE If the conditions under investigation is known to be related to various factors such as age sex or area of residence the population is first divided into these groups or strata & a random sample taken within each stration. SAMPLING BY STAGES Ex:- in the two stage sampling the population is divided into a set of 1 st stage sampling units(Primary Sampling Units) & a sample of these units is selected by simple ,random, stratified or systematic sampling. Individuals are then chosen from each of these primary units any method of samplings. Size of sample is dependent on the statistical characteristics of the data to be collected. Larger the sample less the sampling variation i.e. less chance of misleading result.
D.CODUCTING EXAMINATIONS Obtaining approval from the authorities Budgeting Scheduling Emergency cases & referrals Validity & reliability of data Personnel & organization Instruments & supplies Examination area Method of examination, criteria for diagnosis ,indices. Type I-complete examination using mouth mirror & explorer, illumination ,full mouth radiographs & additional diagnostic method such as study model pulp testing , transillumination,lab investigation.
Type II- mouth mirror, explorer , illumination, bitewing radiographs & periapical radiographs. Type III- only mouth mirror explorer , illumination Type IV- this is a screening procedure only using a tongue depressor & available illumination. Note – Type II is used in clinical trials Type III is used in epidemiological surveys Type IV in inspection of school children & to discover the children who need treatment.
E.ANALYSING THE DATA F.DRAWING THE CONCLUSION G.PUBLISHING THE REPORTS should include following information