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Sample size estimation: an overview with applications to orthodontic clinical trial designs
Nikolaos Pandis1, Argy Polychronopoulou, Theodore Eliades
1Department of Orthodontics and Dentofacial Orthopedics, Dental School/Medical Faculty, University of Bern, Bern, Switzerland. npandis@yahoo.com
Summary
Accurate sample size calculation is crucial for credible clinical trials, ensuring reliable results and ethical patient enrollment. This guide emphasizes sample size importance for orthodontic randomized controlled trials to improve study design and quality assessment.
Area of Science:
- Clinical Trials Methodology
- Orthodontic Research
Background:
- Sample size estimation directly impacts clinical trial precision and statistical power.
- Inadequate sample sizes undermine scientific validity, ethical justification, and clinical impact.
- Orthodontic clinical trials often receive insufficient emphasis on sample size calculations.
Purpose of the Study:
- To highlight the critical importance of sample size calculations in orthodontic randomized controlled trials.
- To provide orthodontic clinicians with fundamental principles for sample size determination.
- To serve as a guide for designing robust trials and assessing published research quality.
Main Methods:
- Introduction to general principles of sample size calculation.
- Presentation of calculation examples for two-arm parallel orthodontic trials.
- Analysis of working examples and discussion of design complexities.
Main Results:
- Demonstration of sample size calculation methods applicable to orthodontics.
- Analysis of how design choices and complexities influence sample size requirements.
- Emphasis on the link between sample size and trial credibility.
Conclusions:
- Proper sample size calculation is essential for scientifically sound and ethically responsible orthodontic research.
- This article equips clinicians with knowledge to improve study design and critically evaluate existing trials.
- Implementing rigorous sample size estimation enhances the reliability and impact of orthodontic clinical evidence.
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