Study methodology
A cross‐over study design was selected to avoid a more extensive than necessary study sample of a vulnerable patient group. Different data would likely have emerged if the study had been planned as a parallel RCT, where the children in one study arm would have been denied the possibility of meeting the therapy dog. A parallel RCT design would likely have required a large sample size based on a power calculation to account for potential confounding variables, including but not limited to variance in cognitive abilities, temperament, earlier experience of dental treatment, and extent of parental support. There is little guidance from systematic reviews on whether parallel or cross‐over RCTs are preferred for studying the effects of animal‐assisted therapy (Feng et al., A potential shortcoming of this trial in terms of the possible risk of confounding is a relatively short “washout period” between the two clinical examinations. The mean interval between the first and second visit was 2 days, which was intentionally selected not to be too long. The rationale was that we wanted to enable the children to start their treatment in the specialist clinic as soon as possible, considering a possible delay in the remittance process.