1. Start with a relevant research question for your practice
A well-formulated research question typically follows the PICO framework: Population, Intervention, Comparison, and Outcome. For example, a study might investigate whether fluoride varnish (intervention) reduces caries (outcome) in children (population) compared to no treatment (comparison). If the question aligns with your clinical interests, the study is worth exploring further.Reading the abstract will give you a quick overview of the study’s purpose, methods, results, and conclusions. However, don’t rely solely on the abstract—dig deeper to assess the study’s quality and relevance.
2. Prioritise study designs that minimise bias
The design of a study determines the strength of its evidence. Randomised controlled trials (RCTs) are considered the gold standard for evaluating interventions, but other designs such as cohort studies or systematic reviews can also provide valuable insights. For oral health professionals, studies with robust design help minimise bias. Here’s a cheat sheet of evidence hierarchy to help you navigate. The most robust designs start at the top.
- Systematic reviews
- Meta-analyses
- Randomised controlled trials
- Observational studies
- Expert opinions
3. Pay close attention to the transparency of the methodology
A study’s methodology determines its validity. Look for details on how participants were selected, how interventions were administered, and how outcomes were measured. For example, in a study on periodontal disease, was the sample size sufficient to detect meaningful differences? Were the diagnostic criteria for periodontal disease clearly defined?
Pay close attention to potential sources of bias, such as selection bias, measurement bias, or confounding factors. A well-conducted study will address these issues transparently. Also, ask: Was the study ethical? Ensure that the study followed ethical guidelines, such as obtaining informed consent and minimising harm to participants.
4. Interpret the clinical relevance of the results
When reviewing the results, focus on both statistical and clinical significance. A statistically significant finding (e.g., p < 0.05) may not always translate to clinical relevance. For instance, a study might show that a new toothpaste reduces plaque by 5%, but is this difference meaningful for your patients? Consider the effect size and confidence intervals.
Those provide a range of plausible values for the true effect. Additionally, look for subgroup analyses that might reveal which patients benefit most from the intervention. It’s also important to understand the difference between relative risk and absolute risk reduction. For example, a treatment that reduces the risk of caries from 4% to 2% has a 50% relative risk reduction but only a 2% absolute risk reduction. Relative risk reduction tells you the percentage drop in risk for one group compared to another, but it can make things sound way more impressive than they actually are.
5. Consider the applicability to your practice
Even a well-conducted study may not be applicable to your patients. Ask yourself: Are the study participants similar to my patients? For example, a study conducted in a hospital setting may not generalise to a community dental practice. Consider local factors, such as patient preferences and resource availability, which play a critical role in translating research into practice. Another useful tool is the needed to treat number (NNT), which tells you how many patients need to receive an intervention for one patient to benefit. A lower NNT indicates a more effective treatment, which can help you prioritise interventions in your practice.
6. Evaluate the credibility of the journal that published the study
Journals with higher impact factors are generally considered more reputable, as they publish research that has been widely cited and influential in the field. However, impact factor alone should not be the sole determinant of a study’s quality. Some niche journals in oral health may have lower impact factors but still publish high-quality, relevant research. Always consider the journal’s reputation, peer-review process, and relevance to your field.
7. Look for conflicts of interest and positive outcome bias
Consider the funding source and potential conflicts of interest. Studies sponsored by industry may be biased toward positive outcomes. Scrutinise the authors’ affiliations and the study’s funding statement to assess potential biases. Transparency about conflicts of interest is a hallmark of trustworthy research.
8. Check for quality peer reviews
Peer-reviewed studies undergo rigorous evaluation by experts in the field, helping to ensure their quality and validity. While peer review is not foolproof, it is a key indicator of a study’s credibility. Be cautious of pre-print studies or those published in non-peer-reviewed journals, as they may not have undergone the same level of scrutiny.
9. Consider the study’s scientific limitations
No study is perfect. Look for a discussion of limitations in the paper, such as small sample sizes, short follow-up periods, or potential biases. A well-written study will acknowledge its weaknesses and discuss how they might affect the results. This transparency is a sign of scientific rigor. Also, ask: Are the conclusions supported by the data? Be wary of studies that overstate their findings or make claims that go beyond the evidence.
10. Reflect on the practical integration of new findings
Finally, ask yourself: How can I apply these findings to my practice? Consider whether the intervention is feasible, cost-effective, and aligned with your patients’ needs and preferences. Evidence-based practice is not just about reading studies—it’s about integrating the best available evidence with clinical expertise and patient values.