The objective of this thesis was to study if dental fear of children and their parents and changes in it are associated, if children and parents can evaluate each other’s fear, and if children’s oral health-related quality of life is associated with their fear.

Two different data from questionnaire surveys were used: (1) Child and parental dental fear was evaluated at three time points and studied as parent/child dyads and at individual level when the children were 11–12, 13–14, and 15–16 years old. The number of participants included in the analyses varied according to the study design from 817 to 2,124. (2) 11–14-year-old children’s oral health-related quality of life and dental fear were evaluated (n=133).

Children of fearful parents were more often fearful in early adolescence, but only girls displayed dental fear also in their mid-adolescence. Neither the parents nor the children were able to correctly evaluate each other’s fear. Dental fear of the children and parents was no longer statistically significantly associated when adjusted to the children’s evaluation of their parents’ dental fear. Dental fear did not change similarly between the parents and their children. Dental fear seems to be more stable among adults than among children. The females were more likely to be fearful than the males. Fearful children had poorer oral health-related quality of life, especially in terms of their social and emotional wellbeing, than non-fearful children.

In addition to oral health, dental fear can affect a child's life in general. Fear should be enquired from the children themselves when studying the fear of 11–16-year-olds. Furthermore, it would be worthwhile to address fear already during the childhood and to acknowledge girls’ higher risk of developing fear.