Crossover Study Design
A clinical trial design in which each participant receives two or more treatments in sequence, serving as their own control, commonly used in dental intervention studies to reduce inter-subject variability.
Full Definition
In a crossover study design, the same participant is exposed to each treatment condition during separate, pre-defined periods, separated by a washout interval to prevent carry-over effects. This design is frequently employed in dental research when studying desensitising agents, oral rinses, or analgesics, as it maximises statistical power with smaller sample sizes. Editors reviewing manuscripts using this design should verify that washout periods, sequence randomisation, and carry-over effect analyses are clearly described. The crossover design is distinct from the split-mouth design, in which different treatments are applied simultaneously to different quadrants of the same patient. Proper reporting requires reference to established guidelines such as CENT (Crossover Trials extension of CONSORT).
Usage
Usage note: Editors should confirm that a washout period is reported and that carry-over effects have been tested or discussed; their omission is a common manuscript deficiency.
In Context
- "A two-period crossover study design was employed, with a four-week washout interval between treatment arms." — Study design section of a clinical trial protocol
- "The crossover design was selected to control for individual variation in salivary flow rates." — Rationale section of a dental research grant application