Comprehensive Guide to Oral Health Research Methods and Indices

Research

The systematic, organized, and objective process of identifying a problem, collecting and analyzing data, and interpreting findings to expand knowledge.

Purposes of Oral Health Research

Identify and solve oral health problems. Develop and evaluate preventive and therapeutic interventions. Assess community programs and outcomes. Strengthen dental hygiene as a profession and science. Promote evidence-based decision-making.

Inductive Reasoning

Begins with specific observations and develops general conclusions or theories.

Deductive Reasoning

Begins with a general principle or theory and applies it to specific cases.

Steps of the Scientific Method

Identify the problem/question, Review the literature, Develop a hypothesis, Design the study, Collect data, Analyze data, Interpret results, Report and disseminate.

Hypothesis

A tentative, testable statement of a relationship between variables.

Research Problem

A clearly defined question or area of concern guiding the study.

Theory

A tested, widely accepted explanation supported by evidence.

Fact

An observation repeatedly confirmed as true.

Replication

Repeating a study to confirm findings.

Experimental Group

Group receiving the intervention or variable being tested.

Control Group

Group not receiving the intervention, used for comparison.

Target Population

Entire group of interest for a study.

Sample

Representative subset of the target population.

Pilot Study

Small preliminary test of methods before the main study.

Control

Procedures to limit or eliminate extraneous effects.

Independent Variable

The factor manipulated by the researcher.

Dependent Variable

The factor measured to see the effect of the manipulation.

Cross-sectional Study

Data collected at one point in time.

Longitudinal Study

Data collected from the same subjects over time.

Clinical Trial

Experiment using human participants to test treatments.

Incidence

Number of new cases in a given time period.

Prevalence

Total number of existing cases in a population.

Placebo

Inactive substitute used to control psychological effects.

Epidemiology

Study of distribution and determinants of disease.

Extraneous Variable

A factor other than the independent variable that may affect results.

Research Process

A cyclical process that includes problem identification, literature review, hypothesis formation, research design, data collection, data analysis, interpretation, and dissemination of findings.

Fundamental Research

Expands scientific knowledge without direct application, such as the study of saliva's molecular role in remineralization.

Applied Research

Solves immediate clinical or community problems, for example, evaluating a new sealant material in children.

Exploratory Research

Identifies new ideas or relationships, such as investigating patient attitudes toward fluoride.

Historical Research

Uses past records to interpret trends, for example, reviewing early oral health education programs.

Epidemiological Research

Studies disease frequency and determinants, such as caries prevalence by socioeconomic status.

Descriptive Research

Observes without intervention, for example, surveying toothbrushing frequency.

Correlational Research

Examines relationships between variables, such as the correlation between smoking and periodontitis.

Experimental Research

Tests cause and effect by manipulation, for example, comparing fluoride toothpaste brands.

Ex Post Facto Research

Studies existing data after events occur, such as reviewing charts for outcomes post-implant.

Quasi-Experimental Research

Similar to experimental but lacks randomization/control, such as implementing a school oral hygiene program in one district.

Primary Sources

Original, firsthand records like research reports, lab logs, and clinical notes.

Secondary Sources

Summaries or analyses of primary data, such as textbooks, reviews, and meta-analyses.

External Criticism

Verifies the authenticity of a document, such as checking publication origin and authorship.

Internal Criticism

Evaluates credibility and accuracy of content, such as assessing bias or misinterpretation in historical conclusions.

Purpose of Sampling

To select a manageable, representative portion of the population that accurately reflects its characteristics, used for efficiency, cost control, and generalization of results.

Random Sampling

Method where all participants have an equal chance, reducing bias, such as drawing names randomly.

Stratified Sampling

Divides population into subgroups to ensure representation of subgroups, such as sampling equal males and females.

Systematic Sampling

Every nᵗʰ subject is chosen, making it easy to implement, such as selecting every 5th record.

Convenience Sampling

Uses available subjects, which is quick but biased, such as patients in a clinic that day.

Large Sample Size Advantages

Reduces sampling error, improves reliability and representativeness, enhances generalizability, and strengthens statistical conclusions.

Objective of Data Collection

To obtain accurate, valid, and objective data to test hypotheses and answer research questions.

Measurement in Research

Assigning numbers to variables according to rules to quantify observations for analysis, such as converting 'plaque severity' into numerical plaque index scores.

Nominal Scale

Categories with no order, such as caries present/absent.

Ordinal Scale

Ordered scale with unequal intervals, such as gingivitis classified as mild, moderate, or severe.

Interval Scale

Equal intervals with no true zero, such as temperature in °C.

Ratio Scale

Equal intervals with a true zero, such as plaque score or number of missing teeth.

Continuous

Infinite values within range

Discrete

Countable categories

Validity

Measures what it's supposed to measure. Accuracy

Reliability

Produces consistent results. Consistency

Standardize procedures

Improves validity and reliability

Calibrate examiners

Improves validity and reliability

Pilot test methods

Improves validity and reliability

Test-Retest

Stability over time

Equivalent Form

Consistency between versions

Split-Half

Internal consistency

Interexaminer

Agreement among examiners

Intraexaminer

Consistency by one examiner

Questionnaire

Attitudes, beliefs

Interview

Personal data

Clinical Exam

Objective assessment

Records/Charts

Existing data

Dental Index

Quantifies the degree or presence of oral conditions using standardized criteria for scoring and comparison.

Purpose of Dental Indices

Quantify disease levels, evaluate treatment or prevention programs, provide baseline data for populations, track trends in oral health, motivate patient self-care.

Criteria for a Good Index

Simple and inexpensive, valid and reliable, sensitive to small changes, objective and reproducible, statistically usable.

Reversible Indices

Measures conditions that can be reversed

Irreversible Indices

Measures cumulative, non-reversible changes

DMF (Teeth)

Counts decayed, missing, filled teeth.

Simplified Oral Hygiene Index (OHI-S)

Six surfaces scored: Maxillary right & left first molars (buccal), Maxillary right central incisor (labial), Mandibular left & right first molars (lingual), Mandibular left central incisor (labial).