There is a lack of evidence for the effective management of dental caries in children's primary teeth. The trial entitled 'Filling Children's Teeth: Indicated Or Not?' (FiCTION) was designed to examine the clinical and cost effectiveness, in primary dental care, of three different approaches to the management of caries in primary teeth. However, before the FiCTION main trial commenced, a pilot trial was designed. Service provider (dentists and other members of the team including dental nurses and practice managers) and participant (child participants and their parents) involvement was incorporated into the pilot trial. The aim of this study is to describe service providers' and users' perspectives on the pilot trial to identify improvements to the conduct and design of the FiCTION main trial.