Plans to expand public child dental services to include preschoolchildren and the recently established training of dental hygienists in Denmark form the background for the present study. The study was performed in a rural municipality located 35 km north of Aarhus. Public child dental services for schoolchildren (6-16 years of age) had been established for several years and were being planned to include preschoolchildren. In cooperation with the personnel in the Child Dental Service a full-time employed dental hygienist developed a communication network with different categories of key-persons (health nurses, private daycare mothers and nursery school teachers). Close records and diaries were kept during the entire 3-year study period. The paper summarises the experience gained from co-operation with a large number of key-persons and illustrates some of the conditions necessary for a successful process. The effect of the program on dental caries is discussed.