NBDHE Scientific Basis of Practice Questions and Answers — Questions and Answers
Question 1: A dental hygienist is developing a research question to investigate the effectiveness of a new power toothbrush in reducing gingivitis compared to a manual toothbrush. Using the PICO format, which component does the manual toothbrush represent?
- Patient/Problem
- Intervention
- Comparison (Correct answer)
- Outcome
Correct answer: Comparison
In the PICO format, 'C' stands for Comparison or Control. It represents the alternative to the main intervention being studied. In this scenario, the new power toothbrush is the 'Intervention,' and the manual toothbrush is the standard practice it is being compared against.
Question 2: A research study concludes that a new mouthrinse leads to a statistically significant reduction in plaque scores (p < 0.05). However, the average reduction was only 0.1 on a 5-point plaque index scale. This finding is BEST described as having:
- High clinical significance but low statistical significance.
- High clinical significance and high statistical significance.
- Low clinical significance despite being statistically significant. (Correct answer)
- Neither clinical nor statistical significance.
Correct answer: Low clinical significance despite being statistically significant.
Statistical significance (indicated by a low p-value) means the result is unlikely due to chance. Clinical significance refers to whether the result has a meaningful, practical impact on patient health. A very small reduction in plaque, even if statistically significant, may not be clinically meaningful for improving the patient's oral health.
Question 3: Which of the following study designs is considered the highest level of evidence for determining the effectiveness of a therapeutic intervention in evidence-based dental hygiene practice?
- Case-control study
- Cohort study
- Systematic review of randomized controlled trials (Correct answer)
- Expert opinion
Correct answer: Systematic review of randomized controlled trials
Systematic reviews of randomized controlled trials (RCTs) are at the top of the evidence hierarchy. They synthesize the results of multiple high-quality RCTs, providing a more comprehensive and reliable conclusion than any single study.
Question 4: A dental hygienist is critically appraising a research article about a new diagnostic test for periodontal disease. The hygienist is evaluating if the researchers were blinded to the results of the 'gold standard' diagnostic method when interpreting the new test's results. This action is primarily aimed at assessing which type of bias?
- Selection bias
- Performance bias
- Detection bias (Correct answer)
- Attrition bias
Correct answer: Detection bias
Detection bias (or ascertainment bias) occurs when the assessment of outcomes is influenced by knowledge of which group a participant is in. Blinding the outcome assessors to the 'gold standard' results helps prevent their interpretation of the new test from being biased.
Question 5: In the field of dental epidemiology, which of the following BEST describes the primary goal of a cross-sectional study?
- To follow a group of individuals over time to determine the incidence of a disease.
- To compare individuals with a disease to those without to identify past exposures.
- To determine the prevalence of a disease and its related factors at a single point in time. (Correct answer)
- To test the effectiveness of a new public health intervention within a community.
Correct answer: To determine the prevalence of a disease and its related factors at a single point in time.
A cross-sectional study provides a 'snapshot' of a population at a specific moment. It is used to measure the prevalence of a disease (how widespread it is) and to identify characteristics or risk factors associated with it at that one point in time.
Question 6: A dental public health program aims to assess the oral hygiene status of an elementary school population by measuring the amount of plaque and calculus present. Which type of index would be most appropriate for this assessment?
- Gingival Index (GI)
- Simplified Oral Hygiene Index (OHI-S) (Correct answer)
- Community Periodontal Index (CPI)
- Dean's Fluorosis Index
Correct answer: Simplified Oral Hygiene Index (OHI-S)
The Simplified Oral Hygiene Index (OHI-S) is designed to assess both debris (plaque) and calculus on six specific tooth surfaces. It is a commonly used index in epidemiological surveys to quickly and efficiently evaluate the oral hygiene status of a population.
NBDHE Scientific Basis of Practice Questions and Answers
A dental hygienist is developing a research question to investigate the effectiveness of a new power toothbrush in reducing gingivitis compared to a manual toothbrush.
Using the PICO format, which component does the manual toothbrush represent?